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The United Nations Sustainable Development Goals (SDGs) describe a course of action to address poverty, protect the planet and ensure prosperity for all (https://sdgs.un.org/goals). More specifically, SDG 6 clarifies how water quality, quantity and access are crucial to human well-being, and yet human activities are compromising water resources through over-exploitation, pollution, as well as contributing to the spread of disease. Globally aquatic ecosystems are highly threatened and concerted efforts by governments and civil society to ‘turn the situation around’ are simply not working. Human-created problems require human-centred solutions and these require different ways of thinking and acting to those behaviour patterns that are contributing to the challenges. In this paper, we first consider causal approaches to attitude change and behaviour modification that are simply not working as intended. We then explore enabling responses such as citizen science and co-engaged action learning as more tenable alternatives. SDG 6 has a focus on clean water and sanitation for all. The SDGs further clarify how the extent to which this goal can be realized depends, to a large extent, on stakeholder engagements and education. Through stakeholder engagements and educational processes, people can contribute towards SDG 6 and the specific indicator and target in SDG 6.b – Stakeholder participation. Following a three-year research process, that investigated a wide range of participatory tools, this paper explores how the Stream Assessment Scoring System (miniSASS; www.minisass.org) can enable members of the public to engage in water quality monitoring at a local level. The paper continues to demonstrate how miniSASS can contribute to the monitoring of progress towards Sustainable Development Goal Target 6.3, by providing a mechanism for data collection indicator 6.3.2. miniSASS is proving popular in southern Africa as a methodology for engaging stakeholder participation in water quality monitoring and management. The technique costs very little to implement and can be applied by children and scientists alike. As a biomonitoring approach, it is based on families of macroinvertebrates that are present in most perennial rivers of the world. The paper concludes by describing how useful the miniSASS technique can be for addressing data gaps for SDG 6.3.2 reporting, and that it can be applied in most regions of the world.

Motivation: COVID-19 has revived focus on improving equitable access to water, sanitation and hygiene (WASH) and health services in developing countries. Most public programming tends to rely on economic indicators to identify and target vulnerable groups. Can expanded targeting criteria that include social status help to improve not only targeting, but also equity in access to WASH and health services? Purpose: This paper assesses the role of social identity in mediating access to WASH and health services, controlling for economic disadvantages such as household wealth, income sources and assets. Methods and approach: We use regression analysis applied to the 2016 Nepal Demographic and Health Survey (DHS) to estimate the relationships between social identity and access to WASH and health services, controlling for wealth (using wealth index quantiles), and remittances (using indicator variables for domestic and international remittances). Findings: We find that differences in access are mediated in large part by caste, and religious and ethnic identity, especially in rural areas; suggesting that the supply of such services is lower for historically disadvantaged communities. In addition, communities with lowest access are not necessarily the most economically disadvantaged, indicating that relying solely on traditional economic indicators to target programs and interventions may not be sufficient to improve equity in access to public health services. Policy implications: The results make a case for broadening indicators beyond the economic criteria for improving targeting of public funds for more inclusive development.

In 2014, Oxford Nanopore Technologies (ONT) introduced an affordable and portable sequencer called MinION. We reviewed emerging applications in water research and assessed progress made with this platform towards ubiquitous genetics. With gt;99% savings in upfront costs as compared to conventional platforms, the MinION put sequencing capacity into the hands of many researchers and enabled novel applications with diverse remits, including in countries without universal access to safe water and sanitation. However, to realize the MinION’s fabled portability, all the auxiliary equipment items for biomass concentration, genetic material extraction, cleanup, quantification, and sequencing library preparation also need to be lightweight and affordable. Only a few studies demonstrated fully portable workflows by using the MinION onboard a diving vessel, an oceanographic research ship, and at sewage treatment works. Lower nanopore sequencing read accuracy as compared to alternative platforms currently hinders MinION applications beyond research, and inclusion of positive and negative controls should become standard practice. ONT’s EPI2ME platform is a major step towards user-friendly bioinformatics. However, no consensus has yet emerged regarding the most appropriate bioinformatic pipeline, which hinders intercomparison of study results. Processing, storing, and interpreting large data sets remains a major challenge for ubiquitous genetics and democratizing sequencing applications.

In Dhaka city and its fringe peri-urban sprawls water for domestic use is an increasingly contested commodity. The location of our research, Gazipur district, bordering the growing city of Dhaka, is the heartland of Bangladesh’s Ready Made Garments (RMG) industry, which has spread unplanned in former wetlands and agrarian belts. However, unlike Dhaka, the almost fully industrialized peri-urban areas bordering the city, like many other such areas globally, function in an institutional vacuum. There are no formal institutional arrangements for water supply or sanitation. In the absence of regulations for mining groundwater for industrial use and weakly enforced norms for effluent discharge, the expansion of the RMG industry and other industries has had a disproportionate environmental impact. In this complex and challenging context, we apply a political economy lens to draw attention to the paradoxical situation of the increasingly “public” lives of poor Bangladeshi women working in large numbers in the RMG industry in situations of increasingly “private” and appropriated water sources in this institutionally liminal peri-urban space. Our findings show that poorly paid work for women in Bangladesh’s RMG industry does not translate to women’s empowerment because, among others, a persisting masculinity and the lack of reliable, appropriate and affordable WASH services make women’s domestic water work responsibilities obligatory and onerous.

Pumped hydro energy storage (PHES) has for years been touted as a suitable alternative for balancing the mismatch between demand and supply of electricity. As the world transits from a fossil fuel-based electricity sector to a renewable energy-based one, PHES is also continuously being used to resolve challenges regarding variable or intermittent sources of energy. This chapter presents lessons from countless literature and studies on the global development and market environment of PHES. The study reveals that critical factors such as investing in public-private research, development and deployment, instituting regulatory frameworks that stimulate innovative operation of PHES, increasing digital operation of PHES systems, and retrofitting PHES facilities could foster the uptake and revolutionize the development of PHES.

Globally, collection of tipping fees is being promoted as a solution to sustain the operation of fecal sludge treatment plants (FSTPs). Currently, there are six large-scale FSTPs in Ghana, of which five were in operation in June 2017. In Kumasi, Sekondi-Takoradi and Tamale, fecal sludge (FS) is co-treated with landfill leachate using waste stabilization ponds (WSPs). In Tema and Accra, FS is treated using WSPs and a mechanical dewatering system coupled with an upflow anaerobic sludge blanket (UASB). The focus of this study is FSTPs and to assess how, and if, the tipping fees set by the municipalities could enable cost recovery to sustain their long-term operation. Using a questionnaire survey to interview plant managers from the public and private sectors, and directors of waste management departments, we found that the overall average operation, maintenance and management (OMamp;M) costs per 1000 m3 of treated waste (FS or FS + leachate) in 2017 were USD89 in Kumasi, USD150 in Tamale, USD179 in Tema, USD244 in Sekondi-Takoradi and USD1,743 in Accra. There were important disparities between FSTPs due to their scale, age, and level of treatment and monitoring. Currently, most FSTPs charge tipping fees that range between USD310 and USD530/1000 m3 of FS, averaging USD421 98/1000 m3 of FS discharged at FSTPs. Our study also showed that the OMamp;M costs of large-scale intensive FSTPs cannot be sustained by relying solely on tipping fees. However, there could be potential to cover the routine expenditures associated with operating smaller FSTPs that relying on WSP technologies.

This chapter provides a survey of pumped hydroelectric energy storage (PHES) in terms of the factors considered in the site selection process: geographic, social, economic, and environmental. Due to the number and complexity of factors considered for this purpose, a multicriteria decision-making model is often used during the selection process. From our study, it is observed that the implementation of a PHES project may come with several environmental concerns, that is land and water requirements, impacts on the fishery industry, aquatic habitat, cultural, historical as well as natural. However, we also observed that many of these concerns are being addressed with improvement in PHES technology.

Urban and peri-urban agriculture (UPA) is widely distributed throughout the Global South. Despite urban population growth and diversifying food habits, UPA delivers an important part of urban food supply, as well as other types of services to cities, such as employment and waste reuse. Nevertheless, the extent and importance of UPA varies between different urban areas, while challenges like limited recognition, land conversion, and water pollution and competition threaten the potential of UPA to contribute to urban resilience. Key investment priorities for research and innovation for overcoming current challenges include incentivized peri-urban zoning, urban allocation of productive lands, and increasing capacities for controlled environment agriculture (CEA). Innovative repositioning of food marketing can help to strengthen supply of healthy food from UPA production, increase decent employment, and turn food markets into nutrition hubs. Priority innovations for contributing to the circular bioeconomy of cities include scaling the safe use of wastewater for irrigation through investments in the adoption of multiple risk-barrier approaches and scaling UPA-based ecosystem services for valorising solid waste and environmental management. Innovations in urban governance are required to support these processes by bringing food systems into urban planning through food mapping and the multisectoral platforms for dialogue and policy formulation across city regions and with vertical levels of government.

Kolkata being a metropolitan city in India has its main municipal solid waste dumpsite situated at Dhapa just adjacent to the East Kolkata Wetlands (Ramsar site). The current prevalent situation at Dhapa is open dumping leading to various contaminations and hazards putting forth the need to look for alternative sites where the landfiilling operation can be shifted to using scientific methods. A user interface (UI)–based analytical hierarchy process (AHP) tool has been developed within the Google Earth Engine (GEE) cloud platform to find out the alternative dumping sites using geospatial layers. AHP function is not available as a native algorithm or developed by any researcher in GEE. The tool has three major functionalities, of which the first one handles the UI elements. The AHP procedure is within another function, and the last function integrates the AHP coefficients to the layers generating the final suitability layer. Users can also upload comparison matrix as GEE asset in the form of CSV file which gets automatically integrated into the AHP to calculate the coefficients and consistency ratio to generate the spatial suitability layers. This approach showcases a generalized AHP function within the GEE environment, which has been done for the first time. The tool is designed in the cloud platform which is dynamic, robust and suitable for use in various AHP-based suitability analysis in environmental monitoring and assessment.

Ensuring the long-term functionality of community-managed rural water supply systems has been a persistent development challenge. It is well established that the technicalities of keeping the systems going are impacted by complex political, social, financial, and institutional challenges. While the shift to federal, three-tiered governance allocates concurrent responsibility for drinking water management to the local government with federal and provincial governments, water and sanitation user groups continue to shoulder the management of local supply systems voluntarily. All three levels have jurisdiction over water-related services resulting in confusion of roles. This study focuses on the local level, where community management of water and sanitation decentralisation is the key approach in this complex tangle of diverse institutions with different actors managing and governing water. User Groups and their Committees in the Guras Rural Municipality of Dailekh district, Karnali province, in West Nepal, provided the case study, which was analysed using Ostromapos;s well-recognised Eight Principles for Sustainable Governance of Common-Pool Resources. The community-based model, established formally through the Water Resource Act 1992 (2049 BS), is critically analysed in light of the changing socioeconomic context through the intervening years. The results highlight the need for stronger collaboration between the rural municipality and users to achieve good water supplies and the risks of losing access and voice in water management for women and marginalised people when inactive user groups are replaced by private or group interests taking control of the water access.

Water scarcity and pollution are major threats for human development in the Middle East and North Africa (MENA) region, and Lebanon is no exception. Wastewater treatment and reuse in agriculture can contribute to addressing the increasing water crisis in the MENA region. However, what is the actual potential of water reuse as a solution for agriculture in Lebanon? This report addresses this question and provides the most comprehensive assessment of water reuse potential up to now. Using geographic information system (GIS) modelling and the best and most recent data available in the country, the report develops a detailed technical assessment of the quantities of treated water available for safe reuse in irrigation, and identifies the wastewater treatment plants that have the highest potential for that purpose. The report also examines the governance barriers that need to be overcome for the water reuse potential to materialize in practice. These barriers include structural shortcomings in the wastewater sector combined with challenges of governance and the lack of a regulatory framework for reuse management. Once the current economic, financial and political crisis in Lebanon eases, addressing these barriers will be key to achieving more and safer water reuse in the country.

Solar-powered irrigation pumps are a vital tool for both climate change adaptation and mitigation. Since most developing countries cannot fully utilize large-scale global funds for climate finance due to limited institutional capacities, small-scale solar irrigation pumps (SIPs) can provide a climate-resilient technological solution. We study the case of a subsidized SIP program in Nepal to understand who likely benefits from a small-scale climate finance program in a developing country setting. We analyze government data on profiles of farmers applying for SIPs and in-depth interviews with different actors along the SIP service chain. We find that vulnerable farmers (women, ethnic minorities, and poor farmers) were less likely than wealthier and non-minority farmers to have access to climate finance subsidies. Even though the government agency gave preference to women and ethnic minority farmers during beneficiary selection, an unrepresentative pool of applicants resulting from social and institutional barriers that prevented them from applying to the program led to an inequitable distribution of subsidized SIPs. The lack of a clear policy framework for allocating climate finance subsidies was a significant constraint. Lack of periodic updating of SIP prices and poor provision of after-sale services were also responsible for the inequitable distribution of subsidized SIPs. We recommend the involvement of local governments in soliciting applications from a wider pool of farmers, periodic revision of SIP prices to reflect market price, replacement of the current fixed subsidy scheme with a variable subsidy scheme, and mandatory provisions of after-sales services.

As urbanization increases, meeting the challenges of urban food supply and food security requires coherent and holistic strategies. Attention too often focuses solely on best practices without addressing the required behavior change. This policy brief highlights the importance of minimizing food loss and waste, which accounts for some 30% of current global production, in order to link and achieve SDGs 2, 11 and 12. The strategy comprises four interrelated elements, namely adopting holistic and circular planning perspectives; facilitating urban and peri-urban farming; integrating innovative behavioral interventions; and providing enabling environments. The G20 has the capacity to act rapidly, without the need for major capital investment, thereby also providing leadership to the entire international community.

Living customary water tenure is the most accepted socio-legal system among the large majority of rural people in sub-Saharan Africa. Based on literature, this report seeks to develop a grounded understanding of the ways in which rural people meet their domestic and productive water needs on homesteads, distant fields or other sites of use, largely outside the ambits of the state. Taking the rural farming or pastoralist community as the unit of analysis, three components are distinguished. The first component deals with the fundamental perceptions of the links between humankind and naturally available water resources as a commons to be shared by all, partially linked to communities’ collective land rights. The second component deals with the sharing of these finite and contested naturally available water resources, especially during dry seasons and droughts. Customary arrangements shape both the ‘sharing in’ of water resources within communities and the ‘sharing out’ with other customary communities or powerful third parties. Since colonial times, communities have been vulnerable to those third parties grabbing water resources and overriding customary uses and governance. The third component deals with infrastructure to store and convey water resources. Since time immemorial, communities have invested in infrastructure for self supply, ranging from micro-scale soil moisture retention techniques to large-scale collective deep wells. As increasingly recognized in both the water, sanitation and hygiene (WASH) and irrigation sectors, this component of self supply is rapidly expanding. In all three components, local diversity is high, with gender, class and other social hierarchies intertwining with social safety nets, neighborliness and moral economies. The study derives two sets of implications for state and non-state policies, laws and interventions. First, state legislation about the sharing of water resources should recognize and protect living customary water tenure, especially through due process in ‘sharing out’ water with powerful third parties. Remarkably, water law, which is dominated by permit systems in sub-Saharan Africa, lags behind other legislation in recognizing customary water tenure (see IWMI Research Report 182). Second, by taking communities’ self supply for multiple uses as a starting point for further water infrastructure development, the WASH, irrigation and other sectors can follow the priorities of communities, including the most vulnerable; identify cost-effective multi-purpose infrastructure; develop local skills; and, hence, contribute more sustainably to achieving more United Nations Sustainable Development Goals (SDGs), in particular SDGs 1, 2, 3, 5, 6 and 13. Further historical and interdisciplinary research to achieve these benefits is recommended.

Solar energy forecasting is considered an essential scientific aspect in supporting efforts to integrate solar energy into power grids. Moreover, solar energy forecasting plays an essential role in mitigating greenhouse gas emissions and conserving energy for future use. This study conducted a bibliometric analysis to assess solar energy forecasting research studies evolution at the continental (Africa) and southern Africa levels. Key aspects of analysis included (i) scientific research trends, (ii) nature of collaboration networks, (iii) co-occurrence of keywords and (iv) emerging themes in solar energy forecasting over the last two decades, between the years 2000–2021. The results indicate that solar energy forecasting research has, on average, expanded by 6.4% and 3.3% in Africa and southern Africa, respectively. Based on the study context, solar energy forecasting research only gained momentum in 2015, peaking in 2019, but it is generally still subtle. The scientific mapping illustrated that only South Africa ranks among the leading countries that have produced high numbers of published documents and also leads in contributions to the research area in both Africa and southern Africa. Three emerging topics were identified from the thematic map analysis— namely, “solar irradiance”, “artificial intelligence” and “clear sky”, which implies that researchers are paying attention to solar irradiance, using modelling techniques that incorporate machine learning techniques. Overall, this study contributes to scientific information on the potential bankability of renewable energy projects that could assist power utilities, governments and policymakers in Africa to enforce the green economy through accelerated decarbonisation of the energy systems and building relationships with developed countries for support and better transitioning to solar energy. From a Water–Energy–Food nexus perspective, the results of this work could assist the scientific community in Africa to take advantage of the inherent interconnectedness of water, energy and food resources, whilst also advancing the use of integrated solutions to shape the focus of solar energy research into a more systems thinking and transdisciplinary approach involving the interconnected primary resources and stakeholders pursuit of the Sustainable Development Goals.

This study investigated the potential of using locally available municipal solid wastes (MSW) (such as food wastes from restaurants, charcoal dust, coconut husk and shell, and sawdust) as feedstock to produce noncarbonized fuel briquettes. A low-cost briquetting machine sourced from Alfaster Industries in Kenya served to demonstrate the concept. Using decomposed food waste resulted in briquettes with higher bulk density (+4%), greater net calorific value (+18%) and lower burning rate (-24%), compared to the use of regular food waste. There was no significant difference in ash content from the two briquette types. The results also indicate that decomposing food waste and mixing it with tree-based raw materials such as coconut waste, charcoal waste or sawdust improves the quality of briquettes, and enhances the temperatures achieved during combustion. This recycling solution has the potential to serve multiple benefits in MSW management for sustainable cities while reducing rural land degradation and deforestation.

The United Nations Food Systems Summit aimed to chart a path toward transforming food systems toward achieving the Sustainable Development Goals. Despite the essentiality of water for food systems, however, the Summit has not sufficiently considered the role of water for food systems transformation. This focus is even more important due to rapidly worsening climate change and its pervasive impacts on food systems that are mediated through water. To avoid that water “breaks” food systems, key food systems actors should 1) Strengthen efforts to retain water-dependent ecosystems, their functions and services; 2) Improve agricultural water management; 3) Reduce water and food losses beyond the farmgate; 4) Coordinate water with nutrition and health interventions; 5) Increase the environmental sustainability of food systems; 6) Explicitly address social inequities; and 7) Improve data quality and monitoring for water-food system linkages.

Fish inhabiting freshwater environments are susceptible to the ingestion of microplastics (MPs). Knowledge regarding MPs in freshwater fish in South Africa is very limited. In this study, the uptake of MPs by common carp (Cyprinus carpio) in the Vaal River in South Africa was assessed. MPs were detected in all of the twenty-six fish examined, 682 particles of MPs were recovered from the gastrointestinal tracts of the fish with an average of 26.23 12.57 particles/fish, and an average abundance of 41.18 52.81 particles/kg. The examination of the physical properties of MPs revealed a predominance on fibers (69%), small-sized particles of less than 0.5 mm (48%), as well as prevelance of coloured MPs (94%), mostly green, blue, and black. Using Raman Spectroscopy, the following plastic polymers were identified: high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), polyethylene terephthalate (PET), and polytetrafluoroethylene (PTFE). To the best of our knowledge, this study, is the first to report MPs uptake by freshwater biota in the Vaal River using common carp as a target organism. It provided evidence of MP contamination in the Vaal.

The use of polluted water to irrigate is an increasing problem in the developing world. Lebanon is a case in point, with heavily polluted irrigation waters, particularly in the Litani River Basin. This study evaluated the potential health risks of irrigating vegetables (radishes, parsley, onions, and lettuce) using three water sources (groundwater, river water, and treated wastewater) and three irrigation methods (drip, sprinkler, and surface) over two growing seasons in 2019 and 2020. Water, crop, and soil samples were analyzed for physicochemical parameters, pathogens, and metals (Cu, Cd, Ni, Cr, and Zn). In addition, the bioaccumulation factor, estimated dietary intakes, health risk index, and target hazard quotients were calculated to assess the health risk associated with metal contamination. The study showed that, for water with less than 2 log E. coli CFU/100 mL, no pathogens (Escherichia coli, salmonella, parasite eggs) were detected in irrigated vegetables, irrespective of the irrigation method. With over 2 log E. coli CFU/100 mL in the water, 8.33% of the sprinkler-and surface-irrigated vegetables, and 2.78% of the drip-irrigated root crops (radishes and onions), showed some degree of parasitic contamination. E. coli appeared only on root crops when irrigated with water having over 3 log CFU/100 mL. The concentrations of most metals were significantly lower than the safe limits of the FAO/WHO of the Food Standards Programme Codex, except for zinc and chromium. The trends in the bioaccumulation factor and the estimated dietary intakes of metals were in the order of Cu lt; Cd lt; Ni lt; Cr lt; Zn. The target hazard quotient values for all metals were lower than 1.0. Under trial conditions, the adoption of drip irrigation with water with less than 3 log E. coli CFU/100 mL proved to be safe, even for vegetables consumed raw, except for root crops such as onions and radishes that should not be irrigated with water having over 2 log E. coli CFU/100 mL. Treated wastewater had no adverse effect on vegetable quality compared to vegetables irrigated with other water sources. These results support efforts to update the Lebanese standards for water reuse in agriculture; standards proposed in 2011 by the FAO, and currently being reviewed by the Lebanese Institution of Standards. This research will inform a sustainable water management policy aimed at protecting the Litani River watershed by monitoring water quality.

In Addis Ababa and its environs, most urban wastewater is discharged into rivers without treatment. This study related urban wastewater characteristics to the prevalence of faecal, antibiotic resistant, and potentially pathogenic bacteria in rivers of the Akaki catchment across six locations, for the dry and wet season. Spatiotemporal variation in bacterial hazards across the catchment was up to 6 log10 units. Cooccurrence of sewage pollution marker gene HF183 in all river samples testing positive for the Vibrio cholerae marker gene ompW, and high levels of these two genes in untreated wastewater, identified human sewage as the likely source of Vibrio cholerae hazards in the catchment. Levels of the marker genes rodA for E. coli, HF183 for human host associated Bacteroides, ciaB for Arcobacter, and ompW for Vibrio cholerae were all higher in the dry season than in the wet season. Marker gene gyrB for Pseudomonas aeruginosa was not detected in the samples. From the sequencing data, notable bacterial genera in the dry season included wastewater pollution indicators Arcobacter and Aeromonas, whereas soil erosion may explain the greater prominence of Legionella, Vicinamibacter, and Sphingomonas during the wet season. Except for the most upstream location, all faecal coliform (FC) counts exceeded WHO standards of 1000 CFU/100 mL for unrestricted irrigation. Concerningly, 0.6–20% of FC had ESBL producing antimicrobial resistance traits. In conclusion, multiple bacterial hazards were of concern for river water users in the Akaki catchment, and elevated in the dry season, when the river water is being used for irrigation of vegetable fields that supply the markets of Addis Ababa. This reflects inadequate treatment and limited dilution of urban wastewater by the natural river flows during periods of low rainfall.

The COVID-19 pandemic has underlined the importance of safe access to sufficient clean water in vulnerable communities, renewing interest in water, sanitation and hygiene (WASH) programs and related targets under Sustainable Development Goal 6 (SDG 6). The purpose of this study was to better understand the obstacles to water access in vulnerable communities and identify ways they might be addressed in five countries in the Mekong Region (Cambodia, Laos, Myanmar, Thailand, Vietnam). To this end, qualitative interviews with 50 government officials and development or health experts were complimented with a quantitative survey of the experiences and views of individuals in 15 vulnerable communities. There were several key findings. First, difficulties in accessing sufficient clean water for drinking and hygiene persist in certain vulnerable communities, including informal urban settlements, remote minority villages, and migrant worker camps. Second, limited rights, high prices, and remote locations were common obstacles to household access to improved water sources. Third, seasonal differences in the availability of clean water, alongside other disruptions to supply such as restrictions on movement in COVID-19 responses, drove households towards lower quality sources. Fourth, there are multiple threats to water quality from source to consumption that should be addressed by monitoring, treatment, and watershed protection. Fifth, stakeholder groups differ from each other and residents of vulnerable communities regarding the significance of water access, supply and quality difficulties, and how they should be addressed. The paper ends with a set of program suggestions addressing these water-related difficulties.

Globally, the use of untreated, often diluted, or partly treated wastewater in agriculture covers about 30 million ha, far exceeding the area under the planned use of well-treated (reclaimed) wastewater which has been estimated in this paper at around 1.0 million ha. This gap has likely increased over the last decade despite significant investments in treatment capacities, due to the even larger increases in population, water consumption, and wastewater generation. To minimize the human health risks from unsafe wastewater irrigation, the WHO’s related 2006 guidelines suggest a broader concept than the previous (1989) edition by emphasizing, especially for low-income countries, the importance of risk-reducing practices from ‘farm to fork’. This shift from relying on technical solutions to facilitating and monitoring human behaviour change is, however, challenging. Another challenge concerns local capacities for quantitative risk assessment and the determination of a risk reduction target. Being aware of these challenges, the WHO has invested in a sanitation safety planning manual which has helped to operationalize the rather academic 2006 guidelines, but without addressing key questions, e.g., on how to trigger, support, and sustain the expected behaviour change, as training alone is unlikely to increase the adoption of health-related practices. This review summarizes the perceived challenges and suggests several considerations for further editions or national adaptations of the WHO guidelines.

The COVID-19 pandemic brought unprecedented socio-economic changes, ushering in a “new (ab)normal” way of living and human interaction. The water sector was not spared from the effects of the pandemic, a period in which the sector had to adapt rapidly and continue providing innovative water and sanitation solutions. This study unpacks and interrogates approaches, products, and services adopted by the water sector in response to the unprecedented lockdowns, heralding novel terrains, and fundamental paradigm shifts, both at the community and the workplace. The study highlights the wider societal perspective regarding the water and sanitation challenges that grappled society before, during, after, and beyond the pandemic. The premise is to provide plausible transitional pathways towards a new (ab)normal in adopting new models, as evidenced by the dismantling of the normal way of conducting business at the workplace and human interaction in an era inundated with social media, virtual communication, and disruptive technologies, which have transitioned absolutely everything into a virtual way of life. As such, the novel approaches have fast-tracked a transition into the 4th Industrial Revolution (4IR), with significant trade-offs to traditional business models and human interactions.

Access to sufficient clean water is important for reducing the risks from COVID-19. It is unclear, however, what influence COVID-19 has had on water insecurities. The objective of this study was to assess the associations between COVID-19 control measures and household water insecurities. A survey of 1559 individuals living in vulnerable communities in five countries (Cambodia, Laos, Myanmar, Thailand, Vietnam) showed that increased needs for clean water to wash hands or facemasks made it more likely a person was water insecure along those dimensions. Water insecurities with respect to handwashing and drinking, in turn, made adoption of the corresponding good practices less likely, whereas in the case of washing facemasks there was no association. Water system infrastructure, environmental conditions such as foods and droughts, as well as gender norms and knowledge, were also important for water insecurities and the adoption of good practices. As domestic water insecurities and COVID-19 control measures are associated with each other, efforts should therefore be directed at identifying and assisting the water insecure at high risk when COVID-19 reaches their communities.

Environmental exposure to active pharmaceutical ingredients (APIs) can have negative effects on the health of ecosystems and humans. While numerous studies have monitored APIs in rivers, these employ different analytical methods, measure different APIs, and have ignored many of the countries of the world. This makes it difficult to quantify the scale of the problem from a global perspective. Furthermore, comparison of the existing data, generated for different studies/regions/continents, is challenging due to the vast differences between the analytical methodologies employed. Here, we present a global-scale study of API pollution in 258 of the world’s rivers, representing the environmental influence of 471.4 million people across 137 geographic regions. Samples were obtained from 1,052 locations in 104 countries (representing all continents and 36 countries not previously studied for API contamination) and analyzed for 61 APIs. Highest cumulative API concentrations were observed in sub-Saharan Africa, south Asia, and South America. The most contaminated sites were in low- to middle-income countries and were associated with areas with poor wastewater and waste management infrastructure and pharmaceutical manufacturing. The most frequently detected APIs were carbamazepine, metformin, and caffeine (a compound also arising from lifestyle use), which were detected at over half of the sites monitored. Concentrations of at least one API at 25.7% of the sampling sites were greater than concentrations considered safe for aquatic organisms, or which are of concern in terms of selection for antimicrobial resistance. Therefore, pharmaceutical pollution poses a global threat to environmental and human health, as well as to delivery of the United Nations Sustainable Development Goals.

Eighty percent of wastewater is left untreated or not reused, exacerbating the water quality challenge, especially in vulnerable communities. This Voices asks: how can we improve wastewater management and convert wastewater into a resource?

The impact of climate change on the availability of water affects all types of land use and sectors. This complexity calls for integrated water resources management and negotiations between sectors on the most important, cost-effective, and productive allocation of water where it is a limited resource. This reflection paper shows examples of adaptation efforts to water scarcity at a scale where gains in water productivity can be derived from intersectoral water reuse and wastewater–freshwater swaps, complementing other water scarcity coping strategies (water savings, long-distance transfer, and desalination). Wastewater treatment for reuse offers opportunities across scales as it allows, for example, donor regions to be compensated with reclaimed water for the release of freshwater for higher-value use, increasing overall economic water productivity in this way. In such water swaps, farmers are compensated with higher water volumes in exchange for higher quality. The reuse of water between sectors offers opportunities to (i) expand the traditional (agricultural) water productivity concept and (ii) significantly increase water productivity at the system level. While rural–urban water reallocation can help mitigate the impacts of climate change, compensating farmers with reclaimed water remains limited for the reasons discussed in the paper.

The Constitution of Nepal 2015 enshrines everyone’s right of access to clean water for drinking and the right to food. The common operationalization of the right to water for drinking is providing access to infrastructure that brings water for drinking and other basic domestic uses near and at homesteads. Challenges to achieving this goal in rural areas include: low functionality of water systems; expansion of informal self supply for multiple uses; widespread de facto productive uses of water systems designed for domestic uses; growing competition for finite water resources; and male elite capture in polycentric decision-making. This paper traces how the Nepali government and nongovernmental organizations in the water, sanitation and hygiene (WASH), irrigation and other sectors have joined forces since the early 2000s to address these challenges by innovating community-led multiple use water services (MUS). The present literature review of these processes complemented by field research supported by the Water for Women Fund focuses on women in vulnerable households. Overcoming sectoral silos, these organizations support what is often seen as the sole responsibility of the WASH sector: targeting infrastructure development to bring sufficient water near and at homesteads of those left behind. Women’s priorities for using this water are respected and supported, which often includes productive uses, also at basic volumes. In line with decentralized federalism, inclusive community-led MUS planning processes build on vulnerable households’ self supply, commonly for multiple uses, and follow their priorities for local incremental infrastructure improvements. Further, community-led MUS builds on community-based arrangements for ‘sharing in’ and ‘sharing out’ the finite water resources in and under communities’ social territories. This realizes the constitutional right to food in line with the Nepal Water Resources Act, 1992, which prioritizes core minimum volumes of water for everyone’s domestic uses and many households’ irrigation. Evidence shows how the alleviation of domestic chores, women’s stronger control over food production for nutrition and income, and more sustainable infrastructure mutually reinforce each other in virtuous circles out of gendered poverty. However, the main challenge remains the inclusion of women and vulnerable households in participatory processes.

Plastic usage increases year by year, and the growing trend is projected to continue. However as of 2017, only 9% of the 9 billion tons of plastic ever produced had been recycled leaving large amounts of plastics to contaminate the environment, resulting in important negative health and economic impacts. Curbing this trend is a major challenge that requires urgent and multifaceted action. Based on scientific and gray literature mainly published during the last 10 years, this review summarizes key solutions currently in use globally that have the potential to address at scale the plastic and microplastic contaminations from source to sea. They include technologies to control plastics in solid wastes (i.e. mechanical and chemical plastic recycling or incineration), in-stream (i.e. booms and clean-up boats, trash racks, and sea bins), and microplastics (i.e. stormwater, municipal wastewater and drinking water treatment), as well as general policy measures (i.e. measures to support the informal sector, bans, enforcement of levies, voluntary measures, extended producer responsibility, measures to enhance recycling and guidelines, standards and protocols to guide activities and interventions) to reduce use, reuse, and recycle plastics and microplastics in support of the technological options. The review discusses the effectiveness, capital expenditure, and operation and maintenance costs of the different technologies, the cost of implementation of policy measures, and the suitability of each solution under various conditions. This guidance is expected to help policymakers and practitioners address, in a sustainable and cost-efficient way, the plastic and microplastic management problem using technologies and policy instruments suitable in their local context.

The benefit of biochar as a soil fertility enhancer is well known and has been broadly investigated. Equally, many tropical and subtropical countries use wastewater for irrigation in urban agriculture. To assess the related health risks, we determined pathogen and heavy metal fate associated with biochar application and wastewater irrigation in the urban agriculture of northern Ghana. Rice (Oryza L.) husk biochar (20 t ha-1), N–P–K 15–15–15 fertilizer (212.5 kg ha-1), and their combinations were evaluated in a field-based experiment. Untreated wastewater and tap water served as irrigation water. Red amaranth (Amaranthus cruentus L.) was used as a test crop and was grown in wet (WS) and dry (DS) cropping seasons. Irrigation water, soil, and vegetables were analyzed for heavy metals, Escherichia coli, fecal coliform, helminth eggs, and Salmonella spp. Unlike the pathogens, analyzed heavy metals from irrigation water and soil were below the FAO/WHO permissible standard for agricultural activities. Wastewater irrigation caused E. coli concentrations ranging from 0.5 to 0.6 (WS) and from 0.7 to 0.8 (DS) log10 colony forming units per gram fresh weight (CFU gFW-1) on vegetables and from 1.7 to 2.1 (WS) and from 0.6 to 1.0 (DS) log10CFU per gram dry weight (gDW-1) in soil. Average log10CFU gFW-1 rates of 6.19 and 3.44 fecal coliform were found on vegetables, whereas in soil, 4.26 and 4.58 log10CFU gDW-1 were observed in WS and DS, respectively. Helminth egg populations were high in wastewater and were transferred to the crops and soil. Biochar did not affect bacteria contamination. Pathogen contamination on vegetables and in soil were directly linked to the irrigation water, with minimal or no difference observed from biochar application.

Access to sufficient and clean freshwater is essential for all life. Water is also essential for food system functioning: as a key input into food production, but also in processing and preparation, and as a food itself. Water scarcity and pollution are growing, affecting poorer populations, particularly food producers. Malnutrition levels are also on the rise, and this is closely linked to water scarcity. The achievement of Sustainable Development Goal (SDG) 2 and SDG 6 are co-dependent. Solutions to jointly improve food systems and water security outcomes that the United Nations Food Security Summit (UNFSS) should consider include: 1) strengthening efforts to retain water-based ecosystems and their functions; 2) improving agricultural water management for better diets for all; 3) reducing water and food losses beyond the farmgate; 4) coordinating water with nutrition and health interventions; 5) increasing the environmental sustainability of food systems; 6) explicitly addressing social inequities in water-nutrition linkages; and 7) improving data quality and monitoring for water-food system linkages, drawing on innovations in information and communications technology (ICT).

The role of hydropower in the renewable energy mix for Africaapos;s green development is widely recognised and underpinned by respective government and development partner funded initiatives. However, the growing demand for energy must be balanced with considerations for resource protection and benefit sharing of water resource developments with vulnerable human communities. An international conference on water stewardship for sustainable hydropower brought together key stakeholders in Nairobi, Kenya. This paper aims to synthesise the key messages of experts who attended the conference, presents the emerging body of good practice policies, plans and action in developing sustainable hydropower in Sub-Saharan Africa, and provides recommendations for the way forward. Outcomes of the conference include considerations, planning for sustainable resource development, resource protection considerations, sharing of resource development benefits, and putting the promise into practice. This discussion describes the nature of our planning and management mistakes in the past, presents good practice options and how to implement sustainable hydropower in the future.

Wastewater-fed aquaculture has a long history, especially in Asia. This report examines three empirical cases of integrated wastewater treatment and aquaculture production. From an aquaculture entrepreneur’s perspective, the combination of fish farming and wastewater treatment in common waste stabilization ponds allows significant savings on capital (pond infrastructure) and running costs (wastewater supporting fish feed). On the other hand, the treatment plant owner will have the benefit of a partner taking over plant maintenance. Given the importance of food safety and related perceptions, the report is focusing on innovative business models where the marketed fish is not in direct contact with the treated wastewater, but only the brood stock or fish feed. The financial analysis of the presented systems shows profitable options for the fish farmer, operational and in part capital cost recovery for the treatment plant, and as the treatment plant operators can stop charging households a sanitation fee, eventually a triple-win situation for both partners and the served community.

Enhancing accountability has become an important objective of the governance reforms over the past two decades. Yet, only a few studies have explored the use of social accountability tools in the water sector in particular. This report aims to fill this gap, based on a case study of a donor-funded water, sanitation and hygiene (WASH) program in Nepal. We document and analyze the effects of two types of social accountability tools implemented by the program: public hearings and social audits. We examined how these tools have contributed to increased transparency, participation, voice and accountability, and in turn discuss their potential to reduce corruption. We relied on qualitative methods to collect data in two case study water supply schemes in two districts of Nepal. The study found that the social accountability tools provided a platform for water users to participate and deliberate on issues related to the execution of WASH schemes. However, the scope of accountability narrowly focused on the integrity of the water user committees but did not provide the political resources and means for communities to hold funding and implementing agencies accountable. Furthermore, attention to budget management has not provided space to address environmental and social justice issues related to payment of wages, access to water and decision-making processes in the design of the water scheme and water allocation. Findings from the study also indicate that the concept of deliberation and downward accountability, as envisioned in international development discourses, does not necessarily match with local power relationships and local cultural norms.

This report assesses the potential of solar photovoltaic (PV) irrigation for smallholder agriculture in Ghana, using elements of business planning and business models with a suitability mapping approach. These approaches take into account the economic as well as environmental sustainability of expanding such technology. Using data from existing solar PV irrigation systems and interviews with key industry actors, the report discusses the regulatory and institutional context for investment in solar PV technology and outlines the technology supply chain, mapping the key actors and their roles. The financial viability of two empirical business cases – directly funding an agribusiness and subsidizing a cooperative model – is analyzed to assess the feasibility of expanding access to the technology. Furthermore, three solar PV irrigation business model scenarios are presented based on insights gained from the two empirical cases as well as from analyzing the existing policy and regulatory framework, the technology supply chain and environmental suitability. The potential for solar PV irrigation pumps is substantial, especially in northern Ghana, although care must be taken to avoid overpumping some aquifers. Achieving this potential will require strengthening the policy framework and making finance available at a reasonable cost. The report identifies alternative financing mechanisms and business models that have been tried elsewhere and can be adapted to Ghana, and makes recommendations to enhance the sustainable uptake of solar PV irrigation.

Wastewater reuse is identified as strategic to help ameliorate scarcity in water-stressed regions around the world. However, to develop it, there is a need to better understand the social, institutional and technological contexts in which it takes place. This article develops a novel socio-technical framework to inform such an analysis and applies it to current wastewater reuse in Egypt. Our analysis highlights the different actors, management activities and practices that shape wastewater collection, transfer, treatment, discharge and/or reuse in different social, technological and environmental contexts in Egypt. It points out bottlenecks of current wastewater reuse policies and programmes.

Fecal sludge (FS)-derived fertilizer material, Fortifer was used in farmers’ field to cultivate different crops under varying soil and agro-climatic conditions in Ghana. The aim was to (1) create awareness among smallholder farmers for widespread use of Fortifer (2) observe the response of crops to Fortifer application by farmers in different agro-ecological zones (3) obtain farmers feedback on the FS-derived product to enhance further dissemination across the country. In total 95 farmers in six locations participated in the farmer-led pilots. Fortifer containing up to 3.0% nitrogen, 3.6% phosphorus, 1.3% potassium and 44.3% organic matter was applied to tomato, rice, maize and pepper in comparison to inorganic fertilizers at recommended rates. Subsequently, farmers’ perception of, and willingness to use the product were studied. Crop yield was significantly higher (p = 0.05) in the Fortifer plots compared to the inorganic fertilizer plots for all the selected crops. Yield was 12% higher for tomato, 27% for rice and maize and 30% for pepper under the Fortifer plots. Farmers indicated that, nutrient content was the most important factor they consider when making fertilizer purchasing decision.

A necessary extension of the concept of Resource Recovery and Reuse with an even higher priority is the prevention and reduction of waste. One concern, in particular, is food waste, which constitutes the largest share of human waste. Target 12.3 of the United Nations Sustainable Development Goals (SDGs) is to ‘halve per capita global food waste at the retail and consumer levels and reduce food losses along production and supply chains, including post-harvest losses, by 2030’. For this report, over 400 businesses were analyzed to identify common approaches and business models to address the food waste challenge. The business models are presented under seven categories – measurement, redistribution, resell, value addition, responsible waste collection, resource recovery, and recycling – with a special focus on their application potential to the Global South.

Implementing a circular economy approach to sanitation requires knowledge of the costs to construct, operate and maintain resource-oriented systems. Yet the dearth of data on costs of urban sanitation in general, and resource-oriented systems in particular, limit opportunities to progress sustainable sanitation in low- and middle-income countries. This paper contributes empirical data on the life-cycle costs of a resource-oriented sanitation system in urban Sri Lanka, addressing a gap in evidence about how much it costs, and who pays, for a system that integrates fecal sludge management with nutrient capture and reuse. Costs across the system life-cycle were analyzed according to: (i) cost type; (ii) phases of the sanitation chain; and (iii) distribution between actors. Over a 25-year lifespan, the system had an annualized cost of USD 2.8/person or USD 11/m3 of septage treated. Revenue from co-compost sales covered reuse-related costs plus 8% of present value costs for other phases of the sanitation chain. Findings affirm both the potential for resource-oriented sanitation to generate revenue, and the need for substantial complementary investment in the overall system. The system was found to be reliant on household investment, yet financially viable from the service provider perspective with revenue from desludging services (89%) and co-compost sales (11%) that exceeded costs over the system lifespan and in most years. The analysis of total costs, financial perspectives, and reuse specifics contributes critical evidence to inform policy and planning that supports a purposeful and equitable transition towards circular economy approaches to sanitation.

Access to sufficient and clean freshwater is essential for all life. Water is also essential for food system functioning: as a key input into food production, but also in processing and preparation, and as a food itself. Water scarcity and pollution are growing, affecting poorer populations, particularly food producers. Malnutrition levels are also on the rise, and this is closely linked to water scarcity. Achievement of Sustainable Development Goal 2 (SDG 2) and Sustainable Development Goal 6 (SDG 6) are co-dependent. Solutions to jointly improve food systems and water security outcomes that the United Nations Food Security Summit (UNFSS) should consider include: 1) Strengthening efforts to retain water-based ecosystems and their functions; 2) Improving agricultural water management for better diets for all; 3) Reducing water and food losses beyond the farmgate; 4) Coordinating water with nutrition and health interventions; 5) Increasing the environmental sustainability of food systems; 6) Explicitly addressing social inequities in water-nutrition linkages; and 7) Improving data quality and monitoring for water-food system linkages, drawing on innovations in information and communications technology (ICT).

Safely managed waste reuse may be a sustainable way to protect human health and livelihoods in agrarian-based countries without adequate sewerage. The safe recovery and reuse of fecal sludge-derived fertilizer (FSF) has become an important policy discussion in low-income economies as a way to manage urban sanitation to benefit peri-urban agriculture. But what drives the user acceptance of composted fecal sludge? We develop a preference-ranking model to understand the attributes of FSF that contribute to its acceptance in Karnataka, India. We use this traditionally economic modeling method to uncover cultural practices and power disparities underlying the waste economy. We model farmowners and farmworkers separately, as the choice to use FSF as an employer versus as an employee is fundamentally different. We find that farmers who are willing to use FSF prefer to conceal its origins from their workers and from their own caste group. This is particularly the case for caste-adhering, vegetarian farmowners. We find that workers are open to using FSF if its attributes resemble cow manure, which they are comfortable handling. The waste economy in rural India remains shaped by caste hierarchies and practices, but these remain unacknowledged in policies promoting sustainable ‘business’ models for safe reuse. Current efforts under consideration toward formalizing the reuse sector should explicitly acknowledge caste practices in the waste economy, or they may perpetuate the size and scope of the caste-based informal sector.

Recycling of wastewater provides a substantial solution to the global issue of water scarcity and high water use in aquaculture. However, this sustainable way of wastewater use has not been given much attention and exploration. This study focused on the consumer preference for fish grown in treated wastewater as well as the effect of aeration on the growth performance and economic benefit of African catfish (Clarias gariepinus) grown in treated wastewater. Two hundred (200) respondents from two communities (Chirapatre and Gyinyase) near the wastewater treatment plant in Kumasi were interviewed to determine their willingness to accept and pay for African catfish grown in treated wastewater. For the growth trial, a total of 600 fish (of average initial weight 39.12g) were stocked in two maturation ponds with 4 h (3:00am–7:00am) of aeration daily. The trial lasted for 12 weeks and variables monitored included the survival, growth performance (weight gain, specific growth rate, and yield) and water quality. Fish cultured in non-aerated wastewater ponds (NWFPs) under similar conditions as in aerated wastewater-fed ponds (AWFPs) served as control. The results indicated most important considerations for consumers in their choice of fish to consume were in order of importance; food safety, freshness of fish, taste and packaging. The proximity of consumers to the treatment plant, the price of fish, religion, and age and whether or not they were fish consumers affected their willingness to pay for African catfish grown in the treated wastewater significantly. For the growth trial, dissolved oxygen concentrations in the aerated ponds were significantly higher than in the NWFPs and this led to more than a doubling of the growth rates in the African catfish grown in the AWFPs (189.10g 11.32) as compared to the NWFPs (90.70g 11.59). The pond aeration improved fish growth significantly (p lt; 0.0098). On economic benefit, the aerated system yielded profits of 618.83 (103.13) as compared to a loss of 104.99 (17.50), which was incurred in the non-aerated ponds. Education of the consumers on the process of wastewater treatment and establishment of food safety guidelines will therefore be recommended to increase consumer interest in consuming fish from the treated wastewater.

Arid areas in East Africa are characterized by physical water scarcity. The physical water scarcity is further exacerbated by poor water quality (mainly salinity and fluoride) of mainly groundwater sources. Combined physical water scarcity and poor water quality makes the region a hydrogeologically difficult environment. Nevertheless, some viable high-yielding aquifers exist in East Africa. Difficult hydrogeology means that the best practices of reaching rural dwellers, towns, and urban centers require specialized financial, technical, and engineering approaches. The chapter describes the hydrogeology difficulty and the ongoing management strategies and its implications for the Water, Sanitation and Hygiene sector in East Africa arid regions.

Large cities in developing countries are facing the challenge of rapid urban population growth, which results in increasing waste generation. In Nairobi, the solid waste situation is characterized by low coverage of collection, pollution from uncontrolled dumping, inefficient public services, unregulated and uncoordinated private sector operators and lack of key solid waste management infrastructure. About 3,121 tons of municipal solid waste (MSW) is generated daily, of which about 850 tons are collected and the remaining is burnt or dumped in unauthorized sites or landfilled in the Dandora dumpsite causing health and environmental problems. The recovery of nutrients from the organic content of MSW for reuse in agriculture has the potential to address the dual challenge of waste management and soil nutrient depletion. This study assessed the economic and environmental impact of decentralized composting business model in Nairobi based on a comparison with the baseline scenario using an indicator expressed in tons CO2 equivalent. The cost–benefit analysis was based on data collected from existing compost plants in Kenya. To assess the sensitivity of the results to variation in input variables, a simulation model was developed using the Monte Carlo method. The decentralized composting business model resulted in a net GHG emission saving of 1.21 tons CO2-eq/ton of compost, being both financially and economically feasible with more than 70% chance of economic success. Assessing the economic and environmental impact is an important tool for decision making and to ensure that the business model results in desired benefits to society.

Sustainable management of municipal solid waste (MSW) is a critical issue around the world, especially in South Asia where waste generation is expected to double by 2050. Closing the food-nutrient cycle through composting biodegradable MSW has the potential to meet human needs, including sanitation and food security, while protecting the environment. We use an interdisciplinary case study approach including systems thinking to assess Sri Lanka’s national MSW composting system, which primarily receives residential and commercial food waste. We embed quantitative compost quality analysis and interviews at 20 composting facilities within a broader qualitative assessment informed by ~60 stakeholders in total. This approach yields insights on how institutional, economic, social, and biophysical aspects of the system are interrelated, and how challenges and solutions can create undesirable and desirable cascading effects, respectively. Such dynamics can create risks of composting facility failure and unintended consequences, diminishing the chances of achieving a sustainable circular food–nutrient system. Compost quality, which was variable, plays a pivotal role within the system—a function of program design and implementation, as well as a determinant of value capture in a circular economy. We make several recommendations to inform future efforts to sustainably manage biodegradable MSW using composting, drawing on our case study of Sri Lanka and prior case studies from other nations. Key among these is the need for increased emphasis on compost product quality and markets in policy and program design and implementation. Targeted measures are needed to improve waste separation, boost compost quality, effectively use compost standards, encourage compost market development, ringfence the revenues generated at municipal compost plants, and identify efficient modes of compost distribution. Such measures require adequate space and infrastructure for composting, resource investment, local expertise to guide effective system management, strong links with the agriculture sector, and continued political support.

The use of food waste (FW) from food services as animal feed through informal agreements has been in practice for many years in Sri Lanka. However, data to show the scale of this practice are inadequate. This paper aims to study the extent of FW diverted to piggeries and the opportunities and challenges in reusing FW as animal feed. The data were collected via telephonic survey from 24 piggery farmers in the Western Province in May 2020. Results revealed that 50% of farmers were rearing 100-300 pigs. Farmers used FW as a major feed source to satisfy 82% of total feed requirement on an average. About 40% of the farmers collected the FW from multiple sources such as hotels, restaurants and canteens. Given that the piggery farms are located in peri-urban areas, the average distance traveled by the farmers is 38 km up and down which indicated the value of FW for them. FW was supplied mostly free of charge; however, 26% of the farmers pay LKR 2 to 40/kg when supplied by intermediaries. FW was collected daily, and the amount collected by the farmers varies 50 to 10000 kg/day depending on demand and supply, with 75% of farmers collected less than 1000 kg/day.

Little is known about the occurrence of emerging pollutants (EPs) in waters in the Middle East and North Africa (MENA) region despite the extensive use of low-quality water there. Available data dealing with the sources, occurrence and removal of EPs within the MENA region in different categories of water is collected, presented and analyzed in this literature review. According to the collected database, the occurrence and removal efficiency of EPs in the water matrix in the MENA region is available, respectively, for 13 and six countries of the 18 in total; no available data is registered for the rest. Altogether, 290 EPs have been observed in different water matrices across the MENA countries, stemming mainly from industrial effluents, agricultural practices, and discharge or reuse of treated wastewater (TWW). Pharmaceutical compounds figure among the most frequently reported compounds in wastewater, TWW, surface water, and drinking water. Nevertheless, pesticides are the most frequently detected pollutants in groundwater. Worryingly, 57 cases of EPs have been reported in different fresh and drinking waters, exceeding World Health Organization (WHO) and European Commission (EC) thresholds. Overall, pharmaceuticals, organic compounds, and pesticides are the most concerning EP groups. The review revealed the ineffectiveness of treatment processes used in the region to remove EPs. Negative removals of some EPs such as carbamazepine, erythromycin, and sulfamethoxazole were recorded, suggesting their possible accumulation or release during treatment. This underlines the need to set in place and strengthen control measures, treatment procedures, standards, and policies for such pollutants in the region.

This report examines social equality aspects related to resource recovery through solid waste composting and wastewater irrigation. The report shows that women are represented in greatest numbers at the base of the recycling chain, most often as informal waste pickers and as sorters of recyclables with limited access to resources and upward mobility. Despite a wide gender gap in the solid waste and sanitation sectors, women play a key role in both municipal waste reduction and food safety where irrigation water is unsafe. Analyzing the gender dimension is important for understanding household responses to recycling programs, differences between the formal and informal sectors as well as along the waste-to-resource value chain from collection to treatment and reuse. The report stresses the important role of women in household waste management, including waste segregation, and the power of women-dominated waste picker associations, where the informal sector plays an essential role alongside the formal sector.

In 2019, Sri Lanka introduced two policies that referred to food waste and the need to reduce it. To understand key stakeholders’ readiness in this context, this study analyzed the food waste perceptions of private and public sectors in Colombo (open markets, supermarkets, hotels, restaurants, canteens, food caterers and key authorities). Interviews were carried out with operational managers and public officials, as well as other stakeholders who have roles in food waste redistribution and reuse, such as NGOs and the livestock sector. So far, the food-waste-related policy recommendations lack an operational inter-institutional home which can build on measures, like standards, regulations and incentives. Thus, most food waste reduction initiatives are initiated by NGOs or by the private sector, e.g., by larger hotels and supermarket chains. These entities were ready to lead by example, based on the understanding that urban food waste is an internal (financial) management challenge. Among smaller local entities, food waste was perceived more as an external issue to be handled by the city’s waste collection services. Although perceptions varied between entities generating smaller or larger quantities of food waste, there was general agreement that suboptimal capacities and mechanisms to quantify, monitor and cost food waste generation appeared to be obstacles for in-depth awareness creation and action. There was significant interest in communication platforms for cross-sectoral learning, win/win collaborations with reliable collection (reuse) services that are currently operational, such as those provided by piggeries, as well as surplus redistribution initiatives if food safety and related liabilities can be addressed effectively.

This chapter documents and assesses available best practices and technologies that can be employed to mitigate the release of microplastics from textiles and tyres into the environment. The chapter follows a life-cycle approach, discussing options implementable at the design and manufacturing, use and end-of-life phases, as well as options for the end-of-pipe capture of microplastics.

With adverse impacts of climate change growing in number and intensity, there is an urgent need to reduce emissions from food systems to net zero. This can only be achieved if rural areas in low- and middle-income countries gain access to clean energy. A review of the research and capacity building contributions of the CGIAR Research Program on Water, Land and Ecosystems (WLE) over the last 10 years suggests important contributions in the areas of energy policy and energy investment planning, cost and feasibility frameworks, and business models for clean energy technology uptake. WLE has also conducted successful pilot projects on solar irrigation to provide an evidence base for scaling up innovative energy initiatives. Finally, the program also considered non-agricultural uses of energy where relevant to food systems, and implemented capacity building activities. Going forward, CGIAR has a key role to play in providing information, supporting access and piloting innovative, scalable clean energy interventions to support the achievement of multiple impacts for the poorest and most food-insecure women and men farmers and entrepreneurs.

In many parts of the world, wastewater irrigation has become a common practice because of freshwater scarcity and to increase resource reuse efficiency. Wastewater irrigation has positive impacts on livelihoods and at the same time, it has adverse impacts related to environmental pollution. Hydrochemical processes and groundwater behaviour need to be analyzed for a thorough understanding of the geochemical evolution in the wastewater irrigated systems. The current study focuses on a micro-watershed in the peri-urban Hyderabad of India, where farmers practice intensive wastewater irrigation. To evaluate the major factors that control groundwater geochemical processes, we analyzed the chemical composition of the wastewater used for irrigation and groundwater samples on a monthly basis for one hydrological year. The groundwater samples were collected in three settings of the watershed: wastewater irrigated area, groundwater irrigated area and upstream peri-urban area. The collected groundwater and wastewater samples were analyzed for major anions, cations and nutrients. We systematically investigated the anthropogenic influences and hydrogeochemical processes such as cation exchange, precipitation and dissolution of minerals using saturated indices, and freshwater-wastewater mixtures at the aquifer interface. Saturation indices of halite, gypsum and fluorite are exhibiting mineral dissolution and calcite and dolomite display mineral precipitation. Overall, the results suggest that the groundwater geochemistry of the watershed is largely controlled by long-term wastewater irrigation, local rainfall patterns and water-rock interactions. The study results can provide the basis for local decision-makers to develop sustainable groundwater management strategies and to control the aquifer pollution influenced by wastewater irrigation.

Globally, 50% of the population relies on on-site sanitation systems (OSS) such as septic tanks and pit latrines and is, hence, in need of Fecal Sludge Management (FSM) solutions. India is a classic example, given that its government built more than 100 million toilets with the majority relying on OSS. With 400 fecal sludge treatment plants (FSTPs) in various stages of planning, procurement and construction, this report comes at an opportune time to present findings on FSM business models already implemented across India. Interviews were conducted with a total of 105 Emptying and Transport (Eamp;T) operators in 72 towns and cities across 16 states in India, 22 representatives from municipalities that own emptying vehicles, 18 FSTP operators and more than 30 institutions. In addition, procurement tenders for Eamp;T and FSTPs in 13 states were analyzed. In total, 18 business models were identified, several with energy or nutrient recovery components. The analysis of Eamp;T operators revealed clear differences that steer a business towards success or failure. The majority of operators still dispose fecal sludge in an unsafe manner, due to the lack of official disposal or treatment sites. In comparison to sewer networks, the capital and operating costs (per capita) of FSTPs were significantly lower. The report provides evidence-based discussions on policies and recommendations for scaling and sustaining FSM.

We describe the technical feasibility of metagenomic water quality analysis using only portable equipment, for example mini-vacuum pumps and filtration units, mini-centrifuges, mini-PCR machines and the memory-stick sized MinION of Oxford Nanopore Technologies, for the library preparation and sequencing of 16S rRNA gene amplicons. Using this portable toolbox on site, we successfully characterized the microbiome of water samples collected from Birtley Sewage Treatment Plant, UK, and its environs. We also demonstrated the applicability of the portable metagenomics toolbox in a low-income country by surveying water samples from the Akaki River around Addis Ababa, Ethiopia. The 16S rRNA gene sequencing workflow, including DNA extraction, PCR amplification, sequencing library preparation, and sequencing was accomplished within one working day. The metagenomic data became available within 24e72 h, depending on internet speed. Metagenomic analysis clearly distinguished the microbiome of pristine samples from sewage influenced water samples. Metagenomic analysis identified the potential role of two bacterial genera not conventionally monitored, Arcobacter and Aeromonas, as predominant faecal pollution indicators/waterborne hazards. Subsequent quantitative PCR analysis validated the high Arcobacter butzleri abundances observed in the urban influenced Akaki River water samples by portable next generation sequencing with the MinION device. Overall, our field deployable metagenomics toolbox advances the capability of scientists to comprehensively monitor microbiomes anywhere in the world, including in the water, food and drinks industries, the health services, agriculture and beyond.

This study fills a knowledge gap about low-income rural communities’ holistic management of multiple water resources to meet their multiple needs through multiple or single-use infrastructure. Six low-income rural villages in Limpopo Province were selected with a diversity in: service levels, surface and groundwater resources, public infrastructure (designed for either domestic uses or irrigation but multiple use in reality) and self-supply (people’s individual or communal investments in infrastructure). Focusing on water-dependent livelihoods and water provision to homesteads, distant fields and other sites of use, three policy-relevant patterns were identified. First, most households have two or more sources of water to their homesteads as a vital buffer to irregular supplies and droughts. Second, infrastructure to homesteads is normally for domestic uses, livestock and, for many households, irrigation for consumption and sale. Public infrastructure to irrigate distant fields is multiple use. Exceptionally, self-supply point sources to distant fields are single use. Water bodies to other sites of use are normally multiple use. As for large-scale infrastructure, multiple-use infrastructure is cost-effective and water-efficient. Third, in four of the six villages people’s self-supply is a more important water source to homesteads than public infrastructure. In all villages, water provided through self-supply is shared. Self-supply improves access to water faster, more cost-effectively and more sustainably than public services do. In line with international debates, self-supply is there to stay and can be supported as a cost-effective and sustainable complementary mode of service delivery. A last potential policy implication regards community-driven planning, design and construction of water infrastructure according to people’s priorities. This may sustainably harness the above-mentioned advantages and, moreover, communities’ ability to manage complex multiple sources, uses and multiple-use infrastructure, whether public or self-supply, as a matter of daily life.

Peri-urban areas are characterized by multifunctional land-use patterns forming a mosaic of built-up and agricultural areas. They are critical for providing food and other agricultural products, livelihood opportunities and multiple ecosystem services, which makes them transformative where urban and rural spaces blend. We analyzed land use changes in a peri-urban micro-watershed in Southern India by using Google Earth data to understand the micro-level spatio-temporal dynamics. This study aims at understanding the peri-urban agriculture and landscape changes as related to the change in use of wastewater and groundwater for irrigation. The temporal dynamics of peri-urban system including the changes in built-up, paragrass, paddy rice and vegetable cultivation, groundwater and wastewater irrigated areas in the watershed were evaluated. The detected changes indicate that, as a consequence of urban pressures, agricultural landscapes are being converted into built-up areas and, at the same time, former barren land is converted to agricultural plots. The mapped land use data are used in landscape change modelling for predicting the peri-urban agricultural dynamics and the driving factors in the watershed. Combined with the mapping and modelling approaches for land use change analysis, our results form the basis for integrated resources management in the wastewater influenced peri-urban systems.

Based on primary data from fecal sludge (FS) treatment plants in three West African urban regions (Ouagadougou in Burkina Faso, Greater Accra in Ghana, and Grand Nokou in Benin), FS collection and treatment patterns were analyzed to identify possible scenarios for resource recovery (RR) through FS co-composting. FS collection was analyzed for up to 7 years, in part per day, month and season, as well as FS characteristics to understand peak flows, FS qualities and related variations to plan for appropriate RR technology and capacities. Overall, the FS volumes collected by vacuum trucks were not significantly affected by the calendar days, months or seasons. Commonly assumed increases during rainy months were, for example, only recorded in Ouagadougou. FS composition appeared highly variable with a pronounced difference in total solids between FS collected from households versus institutional sources, likely indicating that institutions are served more frequently. The analyzed treatment plants appear to be exploited beyond their capacity. RR for reuse can turn sludge disposal from a cost into a source of revenue with co-benefits for farmers and the environment, thereby reducing the pressure on tipping fees. The probability of the added co-compost production being financially viable on its own was estimated for all the study sites, indicating an earliest breakeven point after 5 to 8 years.

Climatic variability and change result in unreliable and uncertain water availability and contribute to water insecurity in Africa, particularly in arid and semi-arid areas and where water storage infrastructure is limited. Managed aquifer recharge (MAR), which comprises purposeful recharge and storage of surface runoff and treated wastewater in aquifers, serves various purposes, of which a prominent one is to provide a means to mitigate adverse impact of climate variability. Despite clear scope for this technology in Africa, the prevalence and range of MAR experiences in Africa have not been extensively examined. The objective of this article is provide an overview of MAR progress in Africa and to inform the potential for future use of this approach in the continent. Information on MAR from 52 cases in Africa listed in the Global MAR Portal and collated from relevant literature was analyzed. Cases were classified according to 13 key characteristics including objective of the MAR project, technology applied, biophysical conditions, and technical and management challenges. Results of the review indicate that: (i) the extent of MAR practice in Africa is relatively limited, (ii) the main objective of MAR in Africa is to secure and augment water supply and balance variability in supply and demand, (iii) the surface spreading/infiltration method is the most common MAR method, (iv) surface water is the main water source for MAR, and (v) the total annual recharge volume is about 158 Mm3 /year. MAR schemes exist in both urban and rural Africa, which exemplify the advancement of MAR implementation as well as its out scaling potential. Further, MAR schemes are most commonly found in areas of high inter-annual variability in water availability. If properly planned, implemented, managed, maintained and adapted to local conditions, MAR has large potential in securing water and increasing resilience in Africa. Ultimately, realizing the full potential of MAR in Africa will require undertaking hydrogeological and hydrological studies to determine feasibility of MAR, especially in geographic regions of high inter-annual climate variability and growing water demand. This, supported by increased research to gauge success of existing MAR projects and to address challenges, would help with future siting, design and implementation of MAR in Africa.

This article reviews the negative impact of anthropogenic changes on groundwater. The main changes in physical and geographical conditions that occur under the impact of anthropogenic pressures and that have the most significant influence on the state of groundwater, as well as a negative impaction the conditions of the formation of groundwater are: changes in the landscape caused by agricultural works, mining, construction of settlements, etc.; changes in the hydrographic network caused the construction of hydroelectric power facilities; changes in the composition of the atmospheric air; changes in the groundwater level regime, climatic conditions. The most significant factor of change in groundwater formation conditions is the progressive anthropogenic pollution of groundwater. It negatively influences the number of resources and their quality.

Investments in irrigation contribute to poverty reduction and enhance food security. This paper considers irrigation investments more broadly in the context of rural–urban linkages and thus examines rural irrigation schemes and peri-urban and urban agriculture using freshwater, groundwater and wastewater. We present case studies from East, West and Southern Africa, while focusing on the imperative of smallholders and of food security and nutrition. Evidence from Big Data and telecoupling show that, amid global change and sustainability issues, irrigation development strengthens connections between humans and nature with notable benefits to food security. Transforming investments to feed the future generation require priority investments in irrigation, solar energy for groundwater pumping, groundwater development policy, and integration of peri-urban and urban agriculture into food systems. Equally important will be no-regret interventions in wastewater reuse, water storage and groundwater buffer, micro-irrigation, and wholesale reconfiguration of farming systems, through anticipatory investments, to safeguard food security and sustainability into the distant future.

Water security is a key in achieving sustainable development goals (SDGs); however, it is gradually becoming a scarce resource due to pressure from both climatic and non-climatic factors. Understanding sources and extend of vulnerability of the water resources is the very frst step to design appropriate strategies aimed at securing water for various uses. This study therefore assessed vulnerability of water resources and its spatial distribution across the Palikas (new local governments) with Gulmi district in Province-5 as the case study. Vulnerability was assessed using an indicator-based framework comprising of two components and six sub-indices. Results showed that Musikot is the highly vulnerable Palika among the 12 Palikas, and Resunga is the least vulnerable. The results are useful for prioritizing the Palikas for allocating resources aimed at targeting new programs for reducing poverty and conserving natural resources.

Urbanisation will be one of the 21st centuryapos;s most transformative trends. By 2050, it will increase from 55% to 68%, more than doubling the urban population in South Asia and Sub-Saharan Africa. Urbanisation has multifarious (positive as well as negative) impacts on the wellbeing of humans and the environment. The 17 UN Sustainable Development Goals (SDGs) form the blueprint to achieve a sustainable future for all. Clean Water and Sanitation is a specific goal (SDG 6) within the suite of 17 interconnected goals. Here we provide an overview of some of the challenges that urbanisation poses in relation to SDG 6, especially in developing economies. Worldwide, several cities are on the verge of water crisis. Water distribution to informal settlements or slums in megacities (e.g. N50% population in the megacities of India) is essentially non-existent and limits access to adequate safe water supply. Besides due to poor sewer connectivity in the emerging economies, there is a heavy reliance on septic tanks, and other on-site sanitation (OSS) system and by 2030, 4.9 billion people are expected to rely on OSS. About 62–93% of the urban population in Vietnam, Sri Lanka, the Philippines and Indonesia rely on septic tanks, where septage treatment is rare. Globally, over 80% of wastewater is released to the environment without adequate treatment. About 11% of all irrigated croplands is irrigated with such untreated or poorly treated wastewater. In addition to acute and chronic health effects, this also results in significant pollution of often-limited surface and groundwater resources in Sub-Saharan Africa and Asia. Direct and indirect water reuse plays a key role in global water and food security. Here we offer several suggestions to mitigate water and food insecurity in emerging economies.

The world is not on track to achieve Sustainable Development Goal 6 on clean water and sanitation by 2030. We urge a rapid change of the economics, engineering and management frameworks that guided water policy and investments in the past in order to address the water challenges of our time.

Monitoring the qualitative status of freshwaters is an important goal of the international community, as stated in the Sustainable Development Goal (SDGs) indicator 6.3.2 on good ambient water quality. Monitoring data are, however, lacking in many countries, allegedly because of capacity challenges of less-developed countries. So far, however, the relationship between human development and capacity challenges for water quality monitoring have not been analysed systematically. This hinders the implementation of fine-tuned capacity development programmes for water quality monitoring. Against this background, this study takes a global perspective in analysing the link between human development and the capacity challenges countries face in their national water quality monitoring programmes. The analysis is based on the latest data on the human development index and an international online survey amongst experts from science and practice. Results provide evidence of a negative relationship between human development and the capacity challenges to meet SDG 6.3.2 monitoring requirements. This negative relationship increases along the course of the monitoring process, from defining the enabling environment, choosing parameters for the collection of field data, to the analytics and analysis of five commonly used parameters (DO, EC, pH, TP and TN). Our assessment can be used to help practitioners improve technical capacity development activities and to identify and target investment in capacity development for monitoring.

Water-efficient agriculture has implied a large increase in energy consumption for irrigation in recent decades. In many irrigation systems, energy costs are now threatening their sustainability. However, new opportunities have arisen for the use of renewable energies in the irrigation sector. These are some of the aspects of the multifaceted multiple-actor ‘water–food–energy’ nexus. Technical, economic and environmental issues are linked in many ways, involving farmers, water users’ associations, energy suppliers, engineers and other stakeholders. The ICID session ‘Irrigation and energy’ triggered discussions on these multiple dimensions. This paper presents a synthesis of the presentations, discussions and conclusions. Four main questions are addressed: How do irrigation productivity and sustainability of water resources exploitation change when farmers have access to energy? What do we know about energy efficiency in irrigation systems, at farm and collective network levels? How can this efficiency be optimized by using advanced technologies, modelling tools, improved management? Is energy production an opportunity for irrigation systems? These questions have been posed based on multiple case studies from different parts of the world. The BRL network, in southern France, illustrates advanced strategies and opportunities to reduce energy consumption and develop energy production at a network level. General conclusions are drawn from this synthesis, illustrating trade-offs and synergies that can be identified in the irrigation sector at different scales, while opportunities for future research are proposed.

This chapter addresses the current state of water and climate finance, the costs of inaction versus the benefits of action, and several ways to access climate finance flows to improve water management as well as water supply and sanitation services, while synergistically mitigating and/or adapting to climate change.

This chapter focuses on the human health impacts associated with changes in water quality and quantity due to climate change. Trends in morbidity and mortality are examined in the context of health risks associated with climate change, and response options related to water supply and sanitation are presented.

This chapter establishes linkages between climate change and various aspects of water management. Adaptation and resilience-building options are presented with respect to water storage – including groundwater – and water supply and sanitation infrastructure, and unconventional water supply options are described. Mitigation options for water management systems are also presented.

Over the last decade, the International Water Management Institute (IWMI) has explored the use of fecal sludge (FS) in combination with other organic waste sources to optimize FS treatment and composting for the production of a safe organic fertilizer, which can – depending on demand – be enriched with crop nutrients or pelletized for volume reduction, delayed decomposition or easier application. Based on IWMI’s experience, this training manual has been compiled for plant managers and trainers to help ensure that staff involved in FS treatment and production, and application of an FS-based co-compost adopt best practices in all processes involved. The manual can be adapted to local needs as required. It also includes information on compost registration and certification, as well as guidelines for co-compost application in the field.

As we rapidly modify the environment around us, researchers have a critical role to play in raising our understanding of the interactions between people and the world in which they live. Knowledge and understanding of these interactions are essential for evidence based decision-making on resource use and risk management. In this paper, we explore three research case studies that illustrate co-evolution between people and water systems. In each case study, we highlight how different knowledge and understanding, stemming from different disciplines, can be integrated by complementing narratives with a quantitative modelling approach. We identify several important research practices that must be taken into account when modelling people-water systems: transparency, grounding the model in sound theory, supporting it with the most robust data possible, communicating uncertainty, recognising that there is no ‘one true model’ and diversity in the modelling team. To support interdisciplinary research endeavours, we propose a three-point plan: (1) demonstrating and emphasising that interdisciplinary collaboration can both address existing research questions and identify new, previously unknown questions at the interface between the disciplines; (2) supporting individual interdisciplinary learning at all career stages and (3) developing group practices and a culture of interdisciplinary collaboration.

There is a proactive interest in recovering water, nutrients and energy from waste streams with the increase in municipal wastewater volumes and innovations in resource recovery. Based on the synthesis of wastewater data, this study provides insights into the global and regional “potential” of wastewater as water, nutrient and energy sources while acknowledging the limitations of current resource recovery opportunities and promoting efforts to fast-track highefficiency returns. The study estimates suggest that, currently, 380 billion m3 (m3 = 1,000 L) of wastewater are produced annually across the world which is a volume fivefold the volume of water passing through Niagara Falls annually. Wastewater production globally is expected to increase by 24% by 2030 and 51% by 2050 over the current level. Among major nutrients, 16.6 Tg (Tg = million metric ton) of nitrogen are embedded in wastewater produced worldwide annually; phosphorus stands at 3.0 Tg and potassium at 6.3 Tg. The full nutrient recovery from wastewater would offset 13.4% of the global demand for these nutrients in agriculture. Beyond nutrient recovery and economic gains, there are critical environmental benefits, such as minimizing eutrophication. At the energy front, the energy embedded in wastewater would be enough to provide electricity to 158 million households. These estimates and projections are based on the maximum theoretical amounts of water, nutrients and energy that exist in the reported municipal wastewater produced worldwide annually. Supporting resource recovery from wastewater will need a step-wise approach to address a range of constraints to deliver a high rate of return in direct support of Sustainable Development Goals (SDG) 6, 7 and 12, but also other Goals, including adaptation to climate change and efforts in advancing “netzero” energy processes towards a green economy.

A water and soil quality baseline study was carried out across the ~ 4500 km2 Vientiane Plain in Lao PDR. Eight water quality and nine soil parameters were analysed using field kits at 95 sites in March 2015. Elevated electrical conductivity and chloride were apparent at two sites due to geogenic leaching from the marine rock-salt present in some areas. Groundwater was acidic in most locations. Nitrate and faecal contamination were also observed from nitrogenous fertilizers (diffuse) and from leaky sewage pits (localised) respectively. Soil quality is neither nutrient deficient nor does it pose a threat to plant growth. Where groundwater is used for drinking, removal of bacterial contamination by simple filtration or boiling is sufficient. In the absence of a functional monitoring network in the Vientiane Plain, periodic surveys of this kind should be performed. The results should be made widely available to the relevant government departments and other stakeholders for better management of the land and water resources.

Recent studies have examined the urban metabolism of cities using urban consumption as a proxy for food inflows but very few studies have aimed at quantifying the role of cities as trade hubs and nutrient sinks of their hinterlands. We therefore examined the linkages between food and animal feed supply, their places of production and nutrient flows through the urban system in the two West African cities of Tamale (Ghana) and Ouagadougou (Burkina Faso). Using primary data on food and feed flows, and secondary data to assess the transformation of these flows into nutrient terms, we show that, besides urban consumption, the function of the two study sites as trade hubs significantly determines nutrient flows. In Tamale, gt; 50% of the nutrient inflows was neither consumed nor was lost in situ but left that city again for other destinations. At least 30% of the incoming cereals was stored in the city for later consumption or export. Ouagadougou relied more on imported goods with 40% of N imported from foreign countries compared to Tamale where only 10% of the N was imported, thus contributing to heavier nutrient extraction in remote production areas.

In low- and middle-income countries, the management of fecal sludge from on-site sanitation systems has received little attention over many decades, resulting in insufficient or missing regulations to guide investments and management options. To address this gap, this report examines existing and emerging guidelines and regulations for fecal sludge management (FSM) along the sanitation service chain (user interface, containment, emptying, transport, treatment, valorization, reuse or disposal). It also draws empirical examples from guidelines across the globe to support policy-makers, planners, and sanitation and health officers, as well as consultants in low- and middle-income countries in the development and design of local and national FSM guidelines and regulations.

Fecal sludge (FS) contains a significant amount of plant nutrients. FS (treated/untreated) has been used as soil ameliorant in several countries. Use of FS-based compost on lettuce may meet reservations due to possible microbiological contamination. The objectives of this research are: (1) To determine the fertilizer value of different formulations of sawdust and fecal sludge compost (SDFS) pellets, and (2) to compare the effect of these SDFS formulations with poultry manure, commercial compost, mineral fertilizer, and non-fertilization on lettuce cultivation. The SDFS products were made by enriching, and pelletized with ammonium sulphate, mineral-NPK, or ammonium sulphate + muriate of potash + triple superphosphate. Lettuce was cultivated in a greenhouse and an open field. The result showed that the saleable fresh weight lettuce yield obtained from all SDFS pellets with/without enrichments were higher than those obtained from commercial compost, poultry manure, mineral fertilizer, or no fertilizer. Cultivation in the open field gave higher yields than those in the greenhouse. No helminth eggs were detected in composts or lettuces. Some fecal coliforms were detected in lettuces fertilized with almost all fertilizers tested, including NPK and non-fertilized control. A properly treated fecal sludge-based fertilizer can be a sustainable solution for lettuce production, which helps urban and peri-urban agriculture.

The Arab region needs a new generation of policies and investments in agricultural water. Agricultural water management has always posed challenges and opportunities in the Arab world. However, unprecedented and accelerating drivers such as climate change, population growth, and land degradation make agricultural water management a more urgent priority than ever before. In addition, as part of the 2030 UN Agenda for Sustainable Development, Arab countries have committed to work towards an ambitious set of development targets, the Sustainable Development Goals (SDGs). Unless the right policies and investments are put in place, it will be difficult to achieve the SDGs, including ending hunger and providing clean water and sanitation for all. This paper is part of an ongoing collaboration between the Food and Agriculture Organization of the United Nations (FAO) and the International Water Management Institute to foster dialogue on agricultural water policies and investments in the context of the FAO led Regional Water Scarcity initiative. The purpose of the paper is to frame the key challenges and opportunities in the sector – including emerging innovations in digital agriculture, water accounting, water supply and wastewater reuse – and to lay out broad strategic directions for action.

Water–Sanitation–Hygiene (WASH) remains vital for the 2030 Agenda for Sustainable Development, yet many countries have not localised the 17 Sustainable Development Goals (SDGs), including SDG 6, which focuses on ensuring the availability and sustainable management of water and sanitation for all. Even in leading African economies such as South Africa, many communities still use the bucket system for sanitation. Using a Composite Index drawn from three indicators whose data were available for 53 of the 54 African countries, it emerged that these states are at various stages of fulfilling the targets set out in SDG 6. The fact that some countries showed declining trends in WASH between 2000 and 2015, is an indication that it will be difficult for Africa to reach the 2030 targets. We recommend that Africa aggressively mobilise resources if it is to attain universal WASH services by 2030, along with other SDG 6-related targets.

Water availability for agriculture will become a growing constraint in areas already under environmental and social stress due to population growth, development, and climatic variability. This limits the potential for expanding irrigated areas and for sustainable intensification, and compromises the ability of smallholder farmers to cater to the increased demand for food. This chapter assesses the key global challenges to water availability and how increasing scarcity and competition for water resources are affecting agricultural productivity, especially that of smallholder producers in Asia and Africa. It further analyzes emerging water management practices that can be sustainably adapted to the needs of smallholder farmers. We provide evidence of the economic viability and potential to improve farmers’ income from such solutions. The opportunity for scaling up high-impact solutions is also assessed against available empirical evidence.

The Indus River Basin faces severe water quality degradation because of nutrient enrichment from human activities. Excessive nutrients in tributaries are transported to the river mouth, causing coastal eutrophication. This situation may worsen in the future because of population growth, economic development, and climate change. This study aims at a better understanding of the magnitude and sources of current (2010) and future (2050) river export of total dissolved nitrogen (TDN) by the Indus River at the sub-basin scale. To do this, we implemented the MARINA 1.0 model (Model to Assess River Inputs of Nutrients to seAs). The model inputs for human activities (e.g., agriculture, land use) were mainly from the GLOBIOM (Global Biosphere Management Model) and EPIC (Environmental Policy Integrated Model) models. Model inputs for hydrology were from the Community WATer Model (CWATM). For 2050, three scenarios combining Shared Socio-economic Pathways (SSPs 1, 2 and 3) and Representative Concentration Pathways (RCPs 2.6 and 6.0) were selected. A novelty of this study is the sub-basin analysis of future N export by the Indus River for SSPs and RCPs. Result shows that river export of TDN by the Indus River will increase by a factor of 1.6–2 between 2010 and 2050 under the three scenarios. N90% of the dissolved N exported by the Indus River is from midstream sub-basins. Human waste is expected to be the major source, and contributes by 66–70% to river export of TDN in 2050 depending on the scenarios. Another important source is agriculture, which contributes by 21–29% to dissolved inorganic N export in 2050. Thus a combined reduction in both diffuse and point sources in the midstream sub-basins can be effective to reduce coastal water pollution by nutrients at the river mouth of Indus.

This study applied a combined analytical hierarchy process (AHP) and goal programming (GP) model to assist decision makers in identifying and prioritizing key investment climate (IC) indicators for waste recycling and reuse enterprises in developing countries. Taking a sector based perspective, key IC criteria and indicators were identified and ranked through country stakeholder workshops in Ghana and Kenya. Three different key decision maker groups namely government agencies, private waste reuse enterprises and non-governmental organizations (NGOs) were involved in identifying and ranking of IC criteria and indicators. The IC criteria identified were policy and infrastructure, finance, business support and markets. A number of indicators across each of the criteria were also identified. By incorporating qualitative and quantitative assessments, criteria and indicator rankings are determined using the AHP and GP model. Model results for Ghana revealed that both the private sector and NGO group ranked finance as the most important criterion while markets was the most important criterion for the government organization group. In contrast, none of the stakeholder groups in Kenya ranked finance as the most important criterion. This indicates that reform priorities of waste reuse sector vary across countries depending on the country’s current situation. The approach adopted in this study enables the criteria and indicators for assessing sector specific investment climate to be clearly identified and the decision making problem to be structured systematically. The exercise can be extended to other countries to elicit priority ranking of IC criteria and indicators for waste reuse enterprises.

This report builds on prior work to provide a new, comprehensive, and balanced view of water security in Pakistan, stressing the importance of the diverse social, environmental, and economic outcomes from water. The report highlights the complex water issues that Pakistan must tackle to improve water security and sheds new light on conventional assumptions around water. It seeks to elevate water security as an issue critical for national development. The report assesses current water security and identifies important water-related challenges that may hinder progress in economic and human development. It identifies unmitigated water-related risks, as well as opportunities where water can contribute to economic growth and poverty reduction. The report analyzes how the performance and architecture of the water sector are related to broader economic, social, and environmental outcomes. It models alternative economic trajectories to identify where intervention can lead to a more water-secure future. A consideration of water sector architecture and performance and how these determine outcome leads to recommendations for improving aspects of sector performance and adjusting sector architecture for better outcomes. The sector performance analysis considers (a) management of the water resource, (b) delivery of water services, and (c) mitigation of water-related risks. The description of sector architecture considers water governance, infrastructure, and financing.

This study assesses the microbial and heavy metal distribution in African catfish (Clarias gariepinus) cultured in waste stabilization pond, and their subsequent suitability for human consumption. Treated wastewater-fed pond (WFP) was used in the culture of the fish with a non-wastewater fed pond (NWFP), fed with ground and rain water as control. Pond water, sediments and fish tissue (gill, liver, gut and skin) samples from both sources were analyzed for pathogens and heavy metal levels. Escherichia coli populations in the sediments and water from the WFP exceeded the maximum permissible limit by 2–3 log units as expected. Significantly higher levels of pathogen contamination were detected in the gut and skin of fish from the WFP than the NWFP. Heavy metal concentrations in all samples fell within the Food and Agricultural Organization (FAO)/World Health Organization (WHO) and National Oceanic and Atmospheric Administration (NOAA) permissible limits except for iron and cadmium. There were significantly higher heavy metal concentrations in gill and liver than the muscle. Even though iron recorded the highest concentrations in fish tissue, the concentrations (0.1–2.0 mg kg-1) were below the expected daily nutritional requirement (1–2 mg) for humans and pose no toxicological risk. However, catfish from WFP would require precautionary measures such as cooking/grilling prior to consumption to avoid pathogen infection.

Hydropower production is altering the Mekong River basin’s riverine ecosystems, which contain the world’s largest inland fishery and provide food security and livelihoods to millions of people. The basin’s hydropower reservoir storage, which may rise from ~2% of its mean annual flow in 2008 to ~20% in 2025, is attenuating seasonal flow variability downstream of many dams with integral powerhouses and large storage reservoirs. In addition, tributary diversions for off-stream energy production are reducing downstream flows and augmenting them in recipient tributaries. To help manage tradeoffs between dam benefits (hydropower, irrigation, flood control, domestic water supply, and navigation) and their consequences for livelihoods and ecosystems, we review observed and projected impacts on river flows along both the Mekong mainstream and its tributaries. We include the effects of diversions and inter-basin transfers, which prior reviews of flow alteration in the Mekong basin have largely neglected. We also discuss the extent to which concurrent changes in climate, water demand, and land use, may offset or exacerbate hydropower-induced flow alteration. Our major recommendations for assessing hydrological impacts in the Mekong and other basins undergoing rapid hydropower development include synchronizing and integrating observational and modeling studies, improving the accuracy of reservoir water balances, evaluating multi-objective reservoir operating rules, examining hydropeaking-induced flow alteration, conducting multi-dam safety assessments, evaluating flow indicators relevant to local ecosystems and livelihoods, and considering alternative energy sources and reservoir sedimentation in long-term projections. Finally, we strongly recommend that dam impact studies consider hydrological alteration in conjunction with fish passage barriers, geomorphic changes and other contemporaneous stressors.

Black soldier fly colonies can produce about 100 times more protein per year than chicken or soybeans, not to mention cattle, on the same area of land. The flies can directly feed on different types of organic wastes, leapfrogging closed loop processes within a circular food economy. Also, where no protein is needed, for example, to feed fish or pigs, the larvae can be processed into high-quality biodiesel. However, can this be done at scale? The answer is ‘Yes’. The report showcases some of the leading global businesses in Black Soldier Fly production.

Billions of people currently lack clean water and sanitation. By 2050 the global population will have grown to nearly 10 billion, over two-thirds of whom will live in urban areas. This Voices asks: what are the research and water-management priorities to ensure clean water and sanitation in the world’s cities?

Natural wetlands are green infrastructure systems that are energy-efficient for wastewater treatment and can be found in diverse geo-environmental settings around the world. Their structure and functions, which defines the treatment efficiencies are highly varied. Wetlands over shallow bedrock and geological lineaments (weak zones) have been known to contribute to groundwater contamination. However, not many studies have been performed to understand the structure in different geological settings to identify the efficiency determining factors. Therefore, it is important to investigate the geological suitability of the natural wetlands. We examined wastewater fed natural wetlands in diverse geological settings aiming at studying the depth, geo-stability, bio-chemical interactions, and hydrogeological attributes that improve the wastewater quality, within the Musi River basin, India. The integrated geophysical scans encompassing electrical resistivity tomography (ERT), hydrogeological test, bathymetric study and hydro-chemical analysis were carried out to explore the physical structure and hydro-dynamic processes in the wetlands. ERT investigations showed that, the depth to bedrock up to 20–25 m devoid of geo-fractures (lineaments) indicated the effective depth of saturated zone as a passable scope for potential bio-chemical interactions, implying the proportionality of the deep seated (deep bedrock) wetland to the pollutant removal efficiency. The lower order of electrical resistivity range 10–35 Om and hydraulic conductivity 2.938 md-1 acquired for saturated weathered zone were found catalyzing the bioremediation, sedimentation, adsorption, redox reactions and ion exchange processes. It caused the deep seated wetland removing nitrate 194.34 kgd-1 (97.18%); sulphate 333.75 kgd-1 (77.70%); phosphate 9.66 kgd-1 (82.53%); microbes 99.99%, BOD 80%, and COD 80% load with discharge 1408 m3d-1 of treated wastewater. Further, the strategies for designating the natural wetlands as wastewater treatment systems are also discussed in this paper.

Globally, many populations face structural and environmental barriers to access safe water, sanitation and hygiene (WASH) services. Among these populations are many of the 200 million pastoralists whose livelihood patterns and extreme environmental settings challenge conventional WASH programming approaches. In this paper, we studied the Afar pastoralists in Ethiopia to identify WASH interventions that can mostly alleviate public health risks, within the populationapos;s structural and environmental living constraints. Surveys were carried out with 148 individuals and observational assessments made in 12 households as part of a Pastoralist Community WASH Risk Assessment. The results show that low levels of access to infrastructure are further compounded by risky behaviours related to water containment, storage and transportation. Additional behavioural risk factors were identified related to sanitation, hygiene and animal husbandry. The Pastoralist Community WASH Risk Assessment visually interprets the seriousness of the risks against the difficulty of addressing the problem. The assessment recommends interventions on household behaviours, environmental cleanliness, water storage, treatment and hand hygiene via small-scale educational interventions. The framework provides an approach for assessing risks in other marginal populations that are poorly understood and served through conventional approaches.

This study reports and analyzes nutrient balances in experimental vegetable production systems of the two West African cities of Tamale (Ghana) and Ouagadougou (Burkina Faso) over a twoyear period comprising thirteen and eleven crops, respectively. Nutrient-use efficiency was also calculated. In Tamale and Ouagadougou, up to 2% (8 and 80 kg N ha–1) of annually applied fertilizer nitrogen were leached. While biochar application or wastewater irrigation on fertilized plots did not influence N leaching in both cities, P and K leaching, as determined with ion-absorbing resin cartridges, were reduced on biochar-amended plots in Tamale. Annual nutrient balances amounted to +362 kg N ha–1, +217 kg P ha–1, and –125 kg K ha–1 in Tamale, while Ouagadougou had balances of up to +692 kg N ha–1, +166 kg P ha–1, and –175 kg K ha–1 y–1. Under farmers’ practice of fertilization, agronomic nutrient-use efficiencies were generally higher in Tamale than in Ouagadougou, but declined in both cities during the last season. This was the result of the higher nutrient inputs in Ouagadougou compared to Tamale and relatively lower outputs. The high N and P surpluses and K deficits call for adjustments in local fertilization practices to enhance nutrient-use efficiency and prevent risks of eutrophication.

Groundwater quantity and quality may be affected by climate change through intricate direct and indirect mechanisms. At the same time, population growth and rapid urbanization have made groundwater an increasingly important source of water for multiple uses around the world, including southern Africa. The present study investigates the coupled human and natural system (CHANS) linking climate, sanitation, and groundwater quality in Ramotswa, a rapidly growing peri-urban area in the semi-arid southeastern Botswana, which relies on the transboundary Ramotswa aquifer for water supply. Analysis of long-term rainfall records indicated that droughts like the one in 2013–2016 are increasing in likelihood in the area due to climate change. Key informant interviews showed that due to the drought, people increasingly used pit latrines rather than flush toilets. Nitrate, fecal coliforms, and caffeine analyses of Ramotswa groundwater revealed that human waste leaching from pit latrines is the likely source of nitrate pollution. The results in conjunction indicate critical indirect linkages between climate change, sanitation, groundwater quality, and water security in the area. Improved sanitation, groundwater protection and remediation, and local water treatment would enhance reliable access to water, de-couple the community from reliance on surface water and associated water shortage risks, and help prevent transboundary tension over the shared aquifer.

Current patterns of agricultural expansion and intensification are bringing unprecedented environmental externalities, including impacts on water quality. While water pollution is slowly starting to receive the attention it deserves, the contribution of agriculture to this problem has not yet received sufficient consideration. We need a much better understanding of the causes and effects of agricultural water pollution as well as effective means to prevent and remedy the problem. In the existing literature, information on water pollution from agriculture is highly dispersed. This repost is a comprehensive review and covers different agricultural sectors (including crops, livestock and aquaculture), and examines the drivers of water pollution in these sectors as well as the resulting pressures and changes in water bodies, the associated impacts on human health and the environment, and the responses needed to prevent pollution and mitigate its risks.

The study is being carried out to investigate the potential for applying SAT in Xaysetha district, Lao PDR and investigation the most suitable site for SAT in Xaysetha district. The methodology was used MCDA, GIS, RRA and semistructured interview to rank SAT site and investigate the physical, social and economic factor at the most suitable site (Nonvay site). The results of SAT ranking indicated that Xaysetha district has a potential to construct up to 3 high suitable site, 8 moderate suitable sites, and 6 low suitable sites. On the other hand, the results of physical, social and economic assessment at Nonvay site represented that DO was exceeded the Lao National Environmental Standard, and the soil infiltration rate is about 24 mm/hour (0.58 m/day). The households around Nonvay site have their own land and they access to water use and have a relationship with 9 organizations. They product wastewater was estimate 150 liter/person/day. And the land available for SAT is worth to US$ 39 million.

Wastewater irrigation is a common livelihood practice in many parts of the developing world. With the continuous irrigation supply, groundwater systems in these regions perceive adverse impacts due to inadequate infrastructure to treat the wastewater. The current study area, Musi River irrigation system, is one such case study located in the peri-urban Hyderabad of South India. The Musi River water, which is used for irrigation, is composed of untreated and secondary treated wastewater from Hyderabad city. Kachiwani Singaram micro-watershed in the peri-urban Hyderabad is practicing wastewater irrigation for the last 40 years. The current quality of (untreated) wastewater used for irrigation is expected to have adverse impacts on the local aquifers, but detailed investigations are lacking. To elucidate the groundwater quality dynamics and seasonality of the wastewater irrigation impacts on the peri-urban agricultural system, we analyzed the groundwater quality on a monthly basis for one hydrological year in the wastewater and groundwater irrigated areas, which exist next to each other. The spatio-temporal variability of groundwater quality in the watershed was analyzed with respect to wastewater irrigation and seasonality using multivariate statistical analysis, multi-way modeling and self-organizing maps. This study indicates the significance of combining various statistical techniques for detailed evaluation of the groundwater processes in a wastewater irrigated agricultural system. The results suggest that concentrations of the major ionic substances increase after the monsoon season, especially in wastewater irrigated areas. Multi-way modeling identified the major polluted groundwaters to come from the wastewater irrigated parts of the watershed. Clusters of chemical variables identified by using self-organizing maps indicate that groundwater pollution is highly impacted by mineral interactions and long-term wastewater irrigation. The study recommends regular monitoring of water resources and development of sustainable management strategies to mitigate the aquifer pollution in wastewater irrigation systems.

This report outlines a business model approach to assessing the feasibility and for encouraging investment in smallholder solar pump irrigation. It also proposes a new methodology for mapping the suitability of solar energy-based irrigation pumps. The proposed business model framework and the methodology for suitability mapping are applied to Ethiopia as a case study, based on data from existing case studies and reports. A brief analysis outlines the regulatory and institutional context for investment in solar pump irrigation, and the ways in which it both constrains and attempts to support investment. The report identifies and outlines three business model scenarios that present opportunities for investing in smallholder solar pump-based irrigation, which would contribute towards sustainable intensification for food and nutrition security. The business model scenarios are based on the value proposition of supplying water to smallholder farmers for irrigated agricultural production. Analysis of potential gains and benefits suggests that direct purchase of solar pumps by farmers is feasible, and that out-grower schemes and pump supplier options with bundled financing offer promising solutions. The potential constraints that different investors may face in up-scaling the business models are also discussed, particularly within institutional, regulatory and financial contexts. The report provides development actors and investors with evidence-based information on the suitability and sustainability of solar pump irrigation in Ethiopia, as well as suggestions for helping to enable smallholders to invest in individually-owned, smallholder photovoltaic (PV) solar pumps.

The Nile Delta and its 2.27 million ha of irrigated land makes up two thirds of Egypt’s agricultural land. It is also the terminal part of a river basin that spans and feeds 11 countries. Increases in dam and irrigation development in upstream parts of the basin is poised to conflict with agricultural expansion and population growth in Egypt. Understanding where and how waters comes into and leaves the delta is therefore a crucial question for the future of the country. This paper revisits the surface and groundwater balances of the delta, emphasizes the additional relevance of drainage water reuse and of the salt balance, and evidences a relative stability of the outflow to the sea over the past 30 years. Various reasons for such a phenomenon and the scope for saving water are explored and discussed. The confusion between plot-level and delta-level efficiency and the relatively limited gains possible are emphasized. Beyond the overall water balance and quantitative issues, water management in the delta remains a complex task of spatially distributing the resource over a complex ramified network. Finally, limitations in the analysis related to data availability and accuracy are emphasized.

Resource recovery and reuse (RRR) of domestic and agro-industrial waste has the potential to contribute to a number of financial, socioeconomic and environmental benefits. However, despite these benefits and an increasing political will, there remain significant barriers to build the required up-front capital which is discouraging private sector engagement. A systematic analysis and understanding of the enabling environment, public and private funding sources, risk-sharing mechanisms and pathways for cost recovery can help to identify opportunities to improve the viability of RRR solutions. This report looks at regulations and policies that remove disincentives for RRR, public and private funding sources for capital and operational costs, risk mitigation options through blending and structuring finance, and options for operational cost recovery.

The safe recovery of nutrients from our waste streams allows us to address the challenges of waste management and soil nutrient depletion conjointly. Commercialization of waste-based organic fertilizers such as FortiferTM (fecal sludge-based co-compost) has the potential to generate significant benefits for developing economies via cost recovery for the sanitation sector and the provision of an alternative agricultural input for smallholder farmers. To guide future FortiferTM businesses, this report presents examples of detailed market assessments, based on farmers’ perceptions, attitudes and willingness-to-pay (WTP) for a pelletized and non-pelletized FortiferTM co-compost. The research was conducted in the Greater Accra and Western regions in Ghana, and in and around Kampala (Uganda), Bangalore (India), Hanoi (Vietnam), and Kurunegala (Sri Lanka). Cross-country analyses helped to understand the effects of market drivers and, where possible, capture lessons learned for knowledge sharing.

This Atlas summarizes recent advances in interdisciplinary approaches and research to address the different components of West African urban food systems, including urban and peri-urban agriculture. It thereby draws on the results of several major collaborative research projects and stakeholder consultations conducted in West Africa over the past two decades, and in particular on the UrbanFoodPlus project in Ghana and Burkina Faso (www.urbanfoodplus.org). The publication targets with its innovative design a broad range of stakeholders.

The use of wastewater to produce food crops particularly vegetables is very prevalent in Addis Ababa, Ethiopia. This practice may pose health risks to farm workers and consumers. Hence, the study was designed to evaluate farmers’ perceptions on irrigation water quality, health risks and health risk mitigation measures in four wastewater-irrigated urban vegetable farming sites in Addis Ababa. Data were collected on farm through 263 individual interviews and 12 focus group discussions. The findings showed that despite differences in levels of knowledge and awareness on health risks, farmers appear informed about the contamination of their irrigation water. The difference in perception to quality consideration of Akaki River/irrigation water is highlighted by the result of Kruskal–Wallis H test analysis which shows significant mean value (1.33) of positive perception toward the water quality by male than female farmers. Interestingly, significant difference (p lt; 0.05) in mean values of awareness toward problems of eating unwashed vegetables is also found between male and female farmers where females seemed to be more aware. Conversely, no significant difference was found in mean value of perception and awareness toward vegetables quality. Among the perceived health risks, skin problems were top-rated health risk while eye burn, sore feet and abdominal pains were rated low across the four farming sites. Although statistically not significant, perception toward consumption-related health risk differed with gender: females assigned relatively high mean score. Irrespective of the farming site and gender differences, the most accepted health risk reduction measures were health promotion programs and cessation of irrigation before harvesting. In view of crop restriction measures, females assigned significantly (p = 0.044) low mean score to planting non-food produce. Akaki-Addis farmers suitability perceptions of planting non-food produce and non-raw eaten crops were significantly (p lt; 0.001) higher than the other farming sites. Therefore, effective site and gender-specific educational programs have the potential for clarifying farmers and consumers’ risks and risk management perceptions and improving practical knowledge, which in turn may help identify adoption barriers, opportunities and incentives.

There is a strong link between gender and energy in view of food preparation and the acquisition of fuel, especially in rural areas. This is demonstrated in a range of case studies from East and West Africa, where biochar, human waste and other waste resources have been used to produce briquettes or biogas as additional high-quality fuel sources. The synthesis of the cases concludes that resource recovery and reuse for energy offers an alternative to conventional centralized grid projects which, while attractive to investors and large-scale enterprises, do not necessarily provide job opportunities for marginalized communities. Reusing locally available waste materials for energy production and as soil ameliorant (in the case of biochar) in small enterprises allows women and youth who lack business capital to begin modest, locally viable businesses. The case studies offer concrete examples of small-scale solutions to energy poverty that can make a significant difference to the lives of women and their communities.

Water and nutrition are linked in multiple ways, but few of these interlinkages are well understood. What is, for example, the exact relationship between water pollution and health or between water resource management and nutrition? Even less is known about the interactions across these various linkages. The importance of better understanding these connections has been highlighted as we pursue the United Nations Sustainable Development Goals (SDGs), which challenge mankind to meet both water security as well as food and nutrition security goals, while also improving water-based ecosystems. It has become increasingly clear that progress toward these goals can only be achieved if measures in the food and nutrition space (SDG 2) do not constrain progress on water (SDG 6) and if measures undertaken to support targets under one of these SGDs also support the outcomes of the other. This paper provides an overview of water–nutrition linkages as reflected in the SDGs, and it identifies key gaps in these linkages and suggests a way forward to support the achievement of both water and nutrition goals and targets.

Climate change is a complex and cross-cutting problem that needs an integrated and transformative systems approach to respond to the challenge. Current sectoral approaches to climate change adaptation initiatives often create imbalances and retard sustainable development. Regional and international literature on climate change adaptation opportunities and challenges applicable to southern Africa from a water-energy-food (WEF) nexus perspective was reviewed. Specifically, this review highlights climate change impacts on water, energy, and food resources in southern Africa, while exploring mitigation and adaptation opportunities. The review further recommends strategies to develop cross-sectoral sustainable measures aimed at building resilient communities. Regional WEF nexus related institutions and legal frameworks were also reviewed to relate the WEF nexus to policy. Southern Africa is witnessing an increased frequency and intensity in climate change-associated extreme weather events, causing water, food, and energy insecurity. A projected reduction of 20% in annual rainfall by 2080 in southern Africa will only increase the regional socio-economic challenges. This is exacerbating regional resource scarcities and vulnerabilities. It will also have direct and indirect impacts on nutrition, human well-being, and health. Reduced agricultural production, lack of access to clean water, sanitation, and clean, sustainable energy are the major areas of concern. The region is already experiencing an upsurge of vector borne diseases (malaria and dengue fever), and water and food-borne diseases (cholera and diarrhoea). What is clear is that climate change impacts are cross-sectoral and multidimensional, and therefore require cross-sectoral mitigation and adaptation approaches. In this regard, a wellcoordinated and integrated WEF nexus approach offers opportunities to build resilient systems, harmonise interventions, and mitigate trade-offs and hence improve sustainability. This would be achieved through greater resource mobilisation and coordination, policy convergence across sectors, and targeting nexus points in the landscape. The WEF nexus approach has potential to increase the resilience of marginalised communities in southern Africa by contributing towards attaining the Sustainable Development Goals (SDGs 1, 2, 3, 6, 7, and 13).

To understand the full value of Resource Recovery and Reuse (RRR), a systematic assessment approach that balances complexity with practicality is required. This report highlights the methods available for quantifying and valuing social, environmental and economic costs and benefits of RRR, focusing on Cost-Benefit Analysis (CBA) as the primary framework. Rather than prescribing a standardized technique for conducting CBA for RRR, this report presents broad frameworks and several examples that can be catered to individual contexts. This results in a suggested eight-step process accompanied with suggested assessment techniques which have to be tailored to the type of question the assessment is meant to answer and related system boundaries.

Globally, more than 60% of the human population live without safely managed sanitation services or even lack access to basic sanitation facilities. In addition, most of the wastewater produced in the world is discharged without proper treatment. Integrated approaches are needed to address these issues and curb the resulting adverse impacts on public health and the environment, and associated societal economic losses. The UN 2030 SDG Agenda provides an important framework towards more sustainable sanitation development, in terms of both safe sanitation access and wastewater management. Innovative solutions that treat and enable productive safe use of water, and recovery of nutrients and organic matter from wastes resources are booming. Some examples of trends are decentralized solutions, separation of waste flows, low/or no-flushing toilets, and converting faecal sludge to energy. These alternative technologies show huge potential to address many development challenges, contributing to multiple SDGs, but achieving upscaling has proved to be a major challenge. A paradigm shift to ‘treatment for reuse’ instead of ‘treatment for disposal’ is already taking place in the wastewater sector. Nevertheless, a better understanding of driving forces and enabling environment, new organizational models based on more service-oriented sanitation provision, and highlighting potential multiple societal benefits to attract investments from new sectors, are identified areas that need further attention.

This chapter reviews the main pollutants from agriculture, its associated impacts, and offers some key pollution mitigation options. The chapter also discusses how agriculture can be a beneficial user of wastewater, and how the practice can become safe.

There is a great potential to close the nutrient recycling loop, support a ‘circular economy’ and improve cost recovery within the waste sector and to create viable businesses via the conversion of waste to organic fertilizers. Successful commercialization of waste-based organic fertilizer businesses however largely depends on a sound market. We used a choice experiment to estimate farmers’ willingness-to-pay (WTP) for faecal sludge and municipal solid waste-based (FSM) compost in Kampala, Uganda and considered three attributes—fortification, pelletization and certification. Our results reveal that farmers are willing to pay for FSM compost and place a higher value on a ‘certified’ compost product. They are willing to pay US $0.4 per kg above the current market price for a similar certified product, which is 67 times higher than the cost of providing the attribute. Farmers are willing to pay US $0.127 per kg for ‘pelletized’ FSM compost, which is lower (0.57 times) than the cost of providing the attribute. On the other hand, farmers require US $0.089 per kg as a compensation to use ‘fortified’ FSM compost. We suggest that future FSM compost businesses focus on a ‘certified and pelletized’ FSM product as this product type has the highest production cost–WTP differential and for which future businesses can capture the highest percentage of the consumer surplus. The demand for FSM compost indicates the benefits that can accrue to farmers, businesses and the environment from the recycling of organic waste for agriculture.

A choice experiment was used to assess households’ willingness-to-pay (WTP) for informational attributes (sources of water used to rear sh, and certi cation) of sh products in Hanoi, Vietnam. The study showed that households’ purchasing decisions are in uenced by their access to information of food product attributes and ascribe an economic value to it. The results indicated that households are willing to pay 51% (USD 1.11 per kg) above the prevailing market price of sh for information to know if wastewater is used to rear the sh they consume. Similarly, they are willing to pay 20% above the prevailing market price of sh (USD 0.43 per kg) to know if freshwater is used as a rearing medium. It is important to note that the increased marginal WTP is for information on whether the sh they consume is raised in wastewater over freshwater. This supports the notion of households’ concern over the safety of consuming wastewater-raised sh. Households are also willing to pay 65% (USD 1.42 per kg) above the prevailing market price for certi ed sh. Based on the cost of sh certi cation and WTP estimates, we found a total economic bene t of USD 172 million for the implementation of a wastewater-raised sh business model in Hanoi. The demand for wastewater-raised sh is likely to be affected by households’ perception of certi cation by a trusted government agency, source of water used to raise the sh, age, income and household size.

Healthy soils are essential for productive and resilient agricultural systems. They are also increasingly recognized as a means to mitigate climate change risks. While solutions for restoring degraded soils and landscapes do exist, improved knowledge and tools are needed to enhance their impacts over time and at scale. WLE has assessed the impacts of various land restoration initiatives and developed a range of tools to better tailor and target investments and interventions to local contexts.

When urban areas expand without concomitant increases in wastewater treatment capacity, vast quantities of wastewater are released to surface waters with little or no treatment. Downstream of many urban areas are large areas of irrigated croplands reliant on these same surface water sources. Case studies document the widespread use of untreated wastewater in irrigated agriculture, but due to the practical and political challenges of conducting a true census of this practice, its global extent is not well known except where reuse has been planned. This study used GIS-based modeling methods to develop the first spatially-explicit estimate of the global extent of irrigated croplands influenced by urban wastewater flows, including indirect wastewater use. These croplands were further classified by their likelihood of using poor quality water based on the spatial proximity of croplands to urban areas, urban wastewater return flow ratios, and proportion of wastewater treated. This study found that 65% (35.9 Mha) of downstream irrigated croplands were located in catchments with high levels of dependence on urban wastewater flows. These same catchments were home to 1.37 billion urban residents. Of these croplands, 29.3 Mha were located in countries with low levels of wastewater treatment and home to 885 million urban residents. These figures provide insight into the key role that water reuse plays in meeting the water and food needs of people around the world, and the need to invest in wastewater treatment to protect public health.

Co-composted dewatered faecal sludge (FS) with organic fractions of municipal solid waste (MSW) has a high potential to be used as an agricultural resource in Sri Lanka. In addition to options for cost recovery in waste management, closing the nutrient and carbon cycles between urban and rural areas, substitution of mineral fertilizers, reduced pollution. and the restoration of degraded arable land are possible with important benefits. Up to now little is known about the usage of FS-MSW as fertilizer and it needs to be studied in order to achieve a better understanding and generate application recommendations. The aim of these experiments has been to evaluate the possibility of substituting mineral fertilization. Two field experiments were conducted on sandy loam to assess the effects of MSW compost and FS-MSW co-compost, its pelletized forms, and mineral-enriched FS-MSW on crop growth. As a short-term crop Raphanus sativus “Beeralu rabu” (radish) was studied for 50 days in a randomized complete block design (RCDB). Results show that, under drought conditions, FS-MSW co-compost increased the yield significantly, while MSW and FS-MSW compost enabled the highest survival rate of the plants. Similarly, the second field trial with a long-term crop, Capsicum anuum “CA-8” (capsicum), was planted as RCBD, using the same treatments, for a cultivation period of 120 days. Results display that during a drought followed by water saturated soil conditions co-compost treatments achieved comparable yields and increased the survival rate significantly compared to the control, fertilized with urea, triple super phosphate, and muriate of potash. Cost-benefit analysis (CBA) revealed that pelletizing decreased the monetary benefits if only fertilizer value is considered. It can be concluded that, under drought and water stress, co-compost ensures comparable yields and enables more resistance, but might not be economical viable as a one-crop fertilizer. These findings need to be validated with further trials under different climate regimes and soils.

Nutrients and water found in domestic treated wastewater are valuable and can be reutilized in urban agriculture as a potential strategy to provide communities with access to fresh produce. In this paper, this proposition is examined by conducting a field study in the rapidly developing city of Hyderabad, India. Urban agriculture trade-offs in water use, energy use and GHG emissions, nutrient uptake, and crop pathogen quality are evaluated, and irrigation waters of varying qualities (treated wastewater, versus untreated water and groundwater) are compared. The results are counter-intuitive, and illustrate potential synergies and key constraints relating to the food–energy–water–health (FEW–health) nexus in developing cities. First, when the impact of GHG emissions from untreated wastewater diluted in surface streams is compared with the life cycle assessment of wastewater treatment with reuse in agriculture, the treatment-plus-reuse case yields a 33% reduction in life cycle system-wide GHG emissions. Second, despite water cycling benefits in urban agriculture, only lt;1% of the nutrients are able to be captured in urban agriculture, limited by the small proportion of effluent divertible to urban agriculture due to land constraints. Thus, water treatment plus reuse in urban farms can enhance GHG mitigation and also directly save groundwater; however, very large amounts of land are needed to extract nutrients from dilute effluents. Third, although energy use for wastewater treatment results in pathogen indicator organism concentrations in irrigation water to be reduced by 99.9% (three orders of magnitude) compared to the untreated case, crop pathogen content was reduced by much less, largely due to environmental contamination and farmer behavior and harvesting practices. The study uncovers key physical, environmental, and behavioral factors that constrain benefits achievable at the FEW-health nexus in urban areas.

Recovering nutrients, water and energy from domestic waste streams, including wastewater and faecal sludge, is slowly gaining momentum in low-income countries. Resource recovery and reuse (RRR) offers value beyond environmental benefits through cost recovery. An expected game changer in sanitation service provision is a business model where benefits accrued via RRR can support upstream sanitation services despite the multitude of private and public stakeholders involved from waste collection to treatment. This paper shows options of how resource recovery and reuse can be an incentive for the sustainable sanitation service chain, by recovering costs where revenue can feed back internally or using generated revenues from reuse to fill financial gaps across the service chain to complement other supporting mechanisms for making waste management more attractive.

The International Water Management Institute (IWMI) is a non-pro t, scienti c research organization focusing on the sustainable use of water and land resources in developing countries. IWMI works in partnership with governments, civil society and the private sector to develop scalable agricultural water management solutions that have a real impact on poverty reduction, food security and ecosystem health. IWMI is a member of CGIAR, a global research partnership for a food-secure future.

Background: Wastewater irrigation for vegetable production is a highly prevalent practice in Addis Ababa and a number of articles have been published on wastewater-irrigated soils and vegetables contaminated with heavy metals. However, to the best of our knowledge, an insight into assessment of human health risks associated with the consumption of vegetable crops grown on wastewater-irrigated soils is non-existent in the city. Long-term effect of wastewater irrigation on the build-up of heavy metals in soils and selected vegetable crops in Addis Ababa urban vegetable farming sites (10) was evaluated. By calculating estimated daily intakes (EDIs) and target hazard quotients (THQs) of metals, health risk associated with the consumption of the analyzed vegetables was also evaluated.; Results: The heavy metal concentrations in irrigation water and soils did not exceed the recommended maximum limits (RMLs). Moreover, Cd, Co, Cr, Cu, Ni and Zn concentrations in all analyzed vegetables were lower than the RML standards. In contrast, Pb concentrations were 1.4–3.9 times higher. Results of two way ANOVA test showed that variation in metals concentrations were significant (p lt; 0.001) across farming site, vegetable type and site x vegetable interaction. The EDI and THQ values showed that there would be no potential health risk to local inhabitants due to intake of individual metal if one or more of the analyzed vegetables are consumed. Furthermore, total target hazard quotients (TTHQs) for the combined metals due to all analyzed vegetables were lower than 1, suggesting no potential health risk even to highly exposed local inhabitants.; Conclusions: There is a great respite that toxic metals like Pb and Cd have not posed potential health risk even after long term (more than 50 years) use of this water for irrigation. However, intermittent monitoring of the metals from irrigation water, in soil and crops may be required to follow/prevent their build-up in the food chain.

The study was to assess the: (i) effect of human urine and other organic inputs on cabbage growth, yield, nutrient uptake, N-use efficiency, and soil chemical characteristics; (ii) economic returns of the use of urine and/or other organic inputs as a source of fertiliser for cabbage production. To meet these objectives, participatory field trials were conducted at Dzorwulu, Accra. Four different treatments (Urine alone, Urine + dewatered faecal sludge (DFS), Urine + poultry droppings (PD), NPK (15-15-15) + PD) were applied in a Randomised Complete Block Design (RCBD) with soil alone as control. Each treatment was applied at a rate of 121 kgNha-1 corresponding to the Nitrogen requirement of cabbage in Ghana. Growth and yield parameters, plant nutrient uptake, and soil chemical characteristics were determined using standard protocols. There were no significant differences between treatments for cabbage head weight, or total and marketable yields. However, unmarketable yield from NPK + PD was 1 to 2 times higher (p lt; 0.05) than those from Urine + PD, Urine + DFS, and Urine alone. Seasonal effect on yields was also pronounced with higher (p lt; 0.001) cabbage head weight (0.95 kg) and marketable yields (12.7 kgha-1) in the dry season than the rainy season (0.42 kg and 6.27 kgha-1). There was higher (p lt; 0.005) phosphorous uptake in cabbage from Urine + PD treated soil than those from other treatments. Nitrogen (N), phosphorous (P), and potassium (K) uptake in the dry season was significantly higher than the rainy season. Soils treated with Urine + DFS and Urine + PD were high in total N content. Urine + PD and Urine + DFS treated soils gave fairly high yield than PD + NPK with a net gain of US$1452.0 and US$1663.5, respectively. The application of urine in combination with poultry droppings has the potential to improve cabbage yields, nutrient uptake, and soil nitrogen and phosphorous content.

The chapter discusses how adopting a holistic methodology that acknowledges socio-logical factors, including community participation, public involvement, social perception, attitudes, gender roles and public acceptance, would lead to improvements in wastewater management practice. It highlights the social dimension as a tool, a lens through which wastewater management and reuse can take on new dimensions. In this way, this chapter aims to shift the focus from perceiving wastewater as a nuisance that needs disposal, toward a resource not to be wasted, which can contribute to food security, human and environmental health, access to energy as well as water security.

The study analyses dis-adoption of biogas technologies in Central Uganda. Biogas technology makes use of livestock waste, crop material and food waste to produce a flammable gas that can be used for cooking and lighting. Use of biogas technology has multiple benefits for the households since it reduces the need for fuelwood for cooking and also produces bio-slurry which is a valuable fertilizer. Despite efforts by Government and Non-Governmental Organizations to promote the biogas technology, the rate of its adoption of biogas technology was found to be low, estimated at 25.8% of its potential. A review of literature showed that the households that dis-adopted biogas technology, did so within a period of 4 years after its installation, yet the lifespan of using it is estimated at 25 years. There was need to examine the factors contributing to dis-adoption. Using cross sectional data collected from Luwero and Mpigi districts found in Central Uganda, a probit model was estimated. The findings showed that an increase in the family size, the number of cattle, number of pigs and the age of the household head reduced the likelihood of biogas technology dis-adoption. Other factors that contributed to dis-adoption included the failure to sustain cattle and pig production that are necessary for feedstock supply, reduced availability of family labor the and inability of the households to repair biogas digesters after malfunctioning. Based on the findings, it was concluded that long term use of biogas technology required improved management practices on the farm so as to sustain livestock production. It is also recommended that quality standards and socio-cultural factors be considered in the design of biogas digesters and end use devices.

The government of Bangladesh is increasingly paying attention to the safe collection and disposal of fecal sludge from pit latrines in rural areas. In this paper, we report on current sludge disposal practices from single-pit latrines, by conducting a survey of 1,091 households with pit latrines in a rural subdistrict of Bangladesh. Almost all households were using their pits, and 90% reported that hiring pit emptiers to empty the pit for reuse was the dominant pit management practice. However, 90% of households also reported that the sludge from these pits would be disposed of in the vicinity of their homes, by digging wide and shallow troughs in the soil to absorb the sludge. These results indicate an urgent need to design an organized service that safely transports fecal sludge away for treatment. The National Committee for Fecal Sludge Management, constituted by the government of Bangladesh, is using these results to design policy for sludge management.

Motivation: Proper management of fecal sludge has significant positive health and environmental externalities. Most research on managing onsite sanitation so far either simulates the costs of, or the welfare effects from, managing sludge in situ in pit latrines. Thus, designing management strategies for onsite rural sanitation is challenging, because the actual costs of transporting sludge for treatment, and sources for financing these transport costs, are not well understood.; Methods: In this paper we calculate the actual cost of sludge management from onsite latrines, and identify the contributions that latrine owners are willing to make to finance the costs. A spreadsheet-based model is used to identify a cost-effective transport option, and to calculate the cost per household. Then a double-bound contingent valuation method is used to elicit from pit-latrine owners their willingness-to-pay to have sludge transported away. This methodology is employed for the case of a rural subdistrict in Bangladesh called Bhaluka, a unit of administration at which sludge management services are being piloted by the Government of Bangladesh.; Results: The typical sludge accumulation rate in Bhaluka is calculated at 0.11 liters/person/day and a typical latrine will need to be emptied approximately once every 3 to 4 years. The costs of emptying and transport are high; approximately USD 13 per emptying event (circa 14% of average monthly income); household contributions could cover around 47% of this cost. However, if costs were spread over time, the service would cost USD 4 per year per household, or USD 0.31 per month per household—comparable to current expenditures of rural households on telecommunications.; Conclusion: This is one of few research papers that brings the costs of waste management together with financing of that cost, to provide evidence for an implementable solution. This framework can be used to identify cost effective sludge management options and private contributions towards that cost in other (context-specific) administrative areas where onsite sanitation is widespread.

Purpose: Faecal sludge (FS) has been co-composted with many organic solid wastes globally. Agricultural wastes, such as oil palm empty fruit bunches (EFB) and cocoa pod husks (CPH), have received very little research attention as far as combining with FS is concerned. This study aimed at co-composting these wastes at different ratios to produce safe compost for use as soilless medium for raising tomato transplants.; Methods: Dewatered FS (DFS) was mixed with shredded EFB and CPH at five different ratios: 1DFS:1EFB, 1DFS:1CPH, and DFS:EFB:CPH in ratios of 1:1:1, 2:1:1, and 2:2:1 and composted for 3 months. Select physicochemical parameters and pathogens were monitored every fortnightly and 3 weeks, respectively.; Results: Maximum temperatures obtained ranged 46.8–54.5 C. Though these temperatures were lower than sanitizing temperatures prescribed by USEPA, no E. coli was found in any of the piles at the end of composting. The ratio 2DFS:2EFB:1CPH was found to be the safest formulation and hence was used to grow tomato under greenhouse conditions. Tomato seeds were sown in three different growing media: 100% FS-based compost, 100% rice husk biochar, and 50% FS-based compost–50% rice husk biochar mix.; Conclusion: Results showed that FS-based compost was a suitable growing medium for tomato. Further studies into the optimal rate and frequency of application of compost teas on tomato are recommended.

Biogas (anaerobic digestion) technology is one of the most viable renewable energy technologies today. However, its economic efficiency depends on the investment costs, costs of operating the biogas plant and optimum methane production. Likewise the profit level also rests on its use directly for cooking or conversion into electricity. The present study assessed the economic potential for a 9000 m3 biogas plant, as an alternative to addressing energy and environmental challenges currently in Ghana. A cost-benefit analysis of the installation of biogas plant at University of Ghana (Legon Sewerage Treatment Plant) yielded positive net present values (NPV) at the prevailing discount rate of 23%. Further the results demonstrate that installation of the plant is capital intensive. Biogas used for cooking was by far the most viable option with a payback period (PBP) of 5 years. Sensitivity analysis also revealed cost of capital, plant and machinery as the most effective factors impacting on NPV and internal rate of return (IRR).

In recent years, interest in fuel briquetting increased because of the opportunity to utilise agricultural residues and the organic fractions of municipal solid waste for energy, with a potential reduction in environmental pollution levels, and where modern heating and cooking fuels for domestic, institutional, commercial and industrial use are not readily available or affordable.

Urban and rural households in low income countries rely on traditional biomass fuels such as charcoal and firewood for cooking and heating purposes, which has an adverse effect on forest resources and on people’s health. A major reason for people to continue these as main sources of fuel for cooking is lack of affordable and reliable alternative sources of energy. Briquettes present a great opportunity to replace traditional biomass fuels for domestic and institutional cooking and industrial heating processes. Through designing and implementing a viable briquette business model, we emphasise that there is a commercial case for the briquette business in Ghana.

Recovering energy, nutrients and water from domestic and agro-waste streams is gaining momentum as a new agenda for promoting sustainable development in developing countries as waste management strategies shift focus from a disposal-oriented approach to a business-oriented approach. The latter approach emphasises value creation and revenue generation (Murray and Buckley, 2010). As most cities in developing countries struggle with the challenge of energy security, recovering energy from different waste streams offers dual benefits – improved waste management and provision of reliable energy to households, institutions and commercial entities.

Most cities in developing countries fail to treat their wastewater comprehensively. Consequently, farmers downstream use poor-quality water for irrigation. This practice implies risks for farmers, consumers and the environment. Conversely, this water supply supports the livelihood of these farmers and other stakeholders along the value chains. Linking safer options for wastewater management with irrigation could therefore be a win–win solution: removing the risks for society and maintaining the bene ts for farmers. However, in developing countries, the high investment costs for the required treatment are problematic and the willingness of farmers to pay for the water (cost recovery) is often questionable. Using a choice experiment, this paper gives insight into farmers’ preferences for wastewater use scenarios, quantifying their willingness to pay. The case study is Hyderabad, India. Farmers there prefer water treatment and are prepared to pay a surplus for this. Considering the costrecovery challenge, this information could be valuable for planning small on site wastewater treatment systems.

The main purpose of this paper is to estimate farmers’ preferences and their willingness to pay (WTP) for ecosystem services derived from four agricultural water management (AWM) and resource recovery and reuse (RRR) intervention options in Burkina Faso, using a choice experiment (CE). These include; small water infrastructure, drip irrigation, recovery of organic matter from waste, and treated wastewater. The design decisions relating to attribute selection, the level of attributes, alternatives and choice tasks were guided by literature, field visits, focus group discussions, expert input and an iterative process of the STATA software to generate an orthogonal main-effects CE design. The data used was generated from a random sample of 300 farm households in the Dano and Ouagadougou municipalities in Burkina Faso. Results from conditional logit, latent class logit and mixt logit models show that farmers have positive and significant preferences for drip irrigation, treated wastewater, and organic matter. However, they are WTP on average more for drip irrigation and organic matter for agricultural sustainability. In line with economic theory, the cost of an intervention reduces demand for a given intervention. These findings can provide policy makers with evidence for agricultural policy design to build farmers’ resilience in the Sahel.

Energy efficient wastewater treatment systems are the current environmental concerns which prompted for the applications of natural wetlands as efficient systems at urban areas. However, a detailed investigation is highly desired to determine the efficiency determining factors relevant to structure and functions of natural wetlands for enhanced wastewater treatment. In view of this the wastewater fed natural wetland is examined by hydro-geophysical means, to decipher i) the effective depth of physico-chemical and microbial reactions, ii) the saturated zone thickness, and iii) hydrogeological attributes enhancing the wastewater quality at Hyderabad city, India. The wetland has been scanned using electrical resistivity tomography (ERT) to decipher its physical structure, and hydrogeological and biogeochemical investigations are performed to understand the dynamics. The low electrical resistivity ( =10.5-34.0 O-m) and moderate hydraulic conductivity (K=2.938 m/d) acquired for saturated zone (10–15 m depth), are found the wastewater enhancing parameters in the wetlands. Geophysically derived laterally constrained inversion (LCI) models explore the maximum saturated zone of wetland up to 25 m as an effective depth for pollutant removal mechanisms. It implies the proportionality between depth to bed rock (confining layer) and wetland efficiency. Further, the bio-geochemical scanning determines the bioremediation, sedimentation, adsorption, redox reactions and ion exchange processes as wetland functions for removing nutrients (77-97%), BOD (78%), COD (76%), and microbes (99.5-99.9%) load with the discharge Q=1812 m3d-1 of treated wastewater. Further, the wetland efficiency integrated with engineered interventions help develop various NTS models with different application scenarios, that are i) constructed wetlands, ii) minimized community wetlands, and iii) single outlet system, suitable for urban, peri-urban and rural areas, respectively. The socio-economic assessment, and farmer-consumers and stakeholders survey suggest that to test and use of wetland systems implementation as a policy guideline under sustainable water management.

Background: In Addis Ababa, where irrigation water for vegetable production is commonly derived from the highly polluted Akaki river, information on microbial contamination of water and irrigated vegetable is scanty. An assessment was done to determine the microbiological quality of irrigation water and lettuce harvested from 10 urban farming sites of Addis Ababa. The efficacy of 5 lettuce washing methods were also assessed. A total of 210 lettuce and 90 irrigation water samples were analyzed for faecal coliform and helminth eggs population levels.; Results: The mean faecal coliform levels of irrigation water ranged from 4.29-5.61 log10 MPN 100 ml-1, while on lettuce, the concentrations ranged from 3.46-5.03 log10 MPN 100 g-1. Helminth eggs and larvae were detected in 80% of irrigation water and 61% of lettuce samples. Numbers ranged from 0.9-3.1 eggs 1000 ml-1 and 0.8-3.7 eggs 100 g-1 wet weight for irrigation water and lettuce, respectively. The helminth eggs identified included those of Ascaris lumbricoides, Hookworm, Enterobius vermicularis, Trichuris trichiura, Taenia and Strongloyides larvae. Ascaris lumbricoides and Hookworm were most prevalent in both irrigation water and lettuce samples. Compared with the WHO recommendations and international standards, the faecal coliform and helminth eggs levels in irrigation water and lettuce samples exceeded the recommended levels. Irrespective of the tested washing methods, faecal coliform and helminth eggs levels were somehow reduced. Among the washing methods, potable tap water washing - rinsing (2 min) followed by dipping in 15 000 ppm vinegar solution for a minute supported the highest faecal coliorm reduction of 1.7 log10 units, whereas lowest reduction of 0.8 log10 units was achieved for the same procedure without vinegar.; Conclusion: Compared with international standards, both faecal coliform and helminth eggs levels exceeded recommended thresholds in water and lettuce, but still in a potential risk range which can be easily mitigated if farmers and households are aware of the potential risk. Aside preventing occupational exposure, potential risk reduction programs should target households which have so far no guidance on how best to wash vegetables. The result of the present study suggest that the vinegar based washing methods are able to reduce faecal coliform towards low level while the physical washing with running water may help to substantially decrease potential risk of helminth parasitic infections.

Background: Faecal matter biochar offers an interesting value proposition where the pyrolysis process guaranties a 100% pathogen elimination, as well as significant reduction in transport and storage weight and volume. Therefore, to evaluate the effect of (1) biochar produced from dried faecal matter from household based septic tanks, and (2) N fertilizer, as well as their interaction on yield and nutrient status of lettuce (Lactuca sativa), lettuce was grown over two growing cycles under glasshouse on two contrasting soils amended once at the start with factorial combination of faecal matter biochar at four rates (0, 10, 20 and 30 t ha-1) with 0, 25 and 50 kg N ha-1 in randomized complete block design.; Results: For both soils, maximum fresh yields were recorded with biochar and combined application of biochar with N treatments. However, the greatest biochar addition effects (with or without N) with regard to relative yield were seen in less fertile sandy loam soil. We have also observed that faecal matter biochar application resulted in noticeable positive residual effects on lettuce yield and tissue nutrient concentrations in the 2nd growing cycle. For both soils, most nutrients analyzed (N, P, K, Mg, Cu and Zn) were within or marginally above optimum ranges for lettuce under biochar amendment.; Conclusions: The application of faecal matter biochar enhances yield and tissue nutrient concentrations of lettuce in two contrasting soils, suggesting that faecal matter biochar could be used as an effective fertilizer for lettuce production at least for two growing cycles. Moreover, the conversion of the faecal matter feedstock into charred product may offer additional waste management benefit as it offers an additional (microbiologically safe) product compared to the more common co-composting.

Agricultural productivity and farm household welfare in areas of severe land degradation can be improved through ecosystem-based interventions. Decisions on the possible types of practices and investments can be informed using evidence of potential benefits. Using farm household data together with a farm level stochastic simulation model provides an initial quantification of farm income and nutrition outcomes that can be generated over a five year period from manure and compost based organic amendment of crop lands. Simulated results show positive income and nutrition impacts. Mean farm income increases by 13% over the planning period, from US$32,833 under the business as usual situation (application of 50 kg DAP and 25 kg urea ha- 1 yr- 1) to US$37,172 under application of 10 t ha- 1 yr- 1 farm yard manure during the first three years and 5 t ha- 1 yr- 1 during the last two years. As a result of organic soil amendment, there is an associated increase in the available calorie, protein, fat, calcium, and iron per adult equivalent, giving the improvement in farm household nutrition. The evidence is substantive enough to suggest the promotion and adoption at scale, in degraded ecosystems, of low cost organic soil amendment practices to improve agricultural productivity and subsequent changes in farm household welfare.

The water, energy, and food resources share a lot in common; they have strong interdependencies and are inadvertently affected by action in any one of them. Therefore, the nexus approach (integrated policies related to water, energy, and food) is required in the face of growing concerns over the future availability and sustainability of these resources. The nexus approach can help achieve at least some of the “Sustainable Development Goals (SDGs)” (e.g., SDG 2, 6, 7, 12, 13, 15). This chapter discusses trends in availability and consumption of the three key resources (i.e., water, energy, and food) and interactions between them, and finally provides some reasons why the nexus approach can help achieve social and economic development goals.

Although the Ganges River Basin (GRB) has abundant water resources, the seasonal monsoon causes a mismatch in water supply and demand, which creates severe water-related challenges for the people living in the basin, the rapidly growing economy and the environment. Addressing these increasing challenges will depend on how people manage the basin’s groundwater resources, on which the reliance will increase further due to limited prospects for additional surface storage development. This report assesses the potential of the Ganges Water Machine (GWM), a concept proposed 40 years ago, to meet the increasing water demand through groundwater, and mitigate the impacts of floods and droughts. The GWM provides additional subsurface storage (SSS) through the accelerated use of groundwater prior to the onset of the monsoon season, and subsequent recharging of this SSS through monsoon surface runoff. It was identified that there is potential to enhance SSS through managed aquifer recharge during the monsoon season, and to use solar energy for groundwater pumping, which is financially more viable than using diesel as practiced in many areas at present. The report further explores the limitations associated with water quality issues for pumping and recharge in the GRB, and discusses other related challenges, including availability of land for recharge structures and people’s willingness to increase the cropping intensity beyond the present level.

Groundwater quality is gaining more importance in groundwater management due to rapid growth in population, agriculture and industrial sectors worldwide. The goal of the present study is to evaluate the groundwater chemistry and to identify the geochemical processes governing the water chemistry in the shallow uncon ned and deeper con ned aquifers in the Eastern Ganges Basin using geochemical methods. Groundwater samples were analysed for major ions and metals (Fe, Mn, Zn, Cu, Pb and As). Shallow wells are found to have high pH, EC, TDS, Ca, Mg, Cl and SO4, and low HCO3/Cl ratio compared to the deep wells. However, the average concentration of Na, HCO3, NO 3, PO 4, F and Mn is not signi cantly varied with depth which indicates that the variation in the water chemistry between uncon ned and con ned aquifers is not only due to the natural processes but also indicates that surface contamination sources could have affected the water chemistry in the uncon ned aquifer. In the uncon ned aquifer, processes like wastewater in ltration, denitri cation, reverse ion exchange and mineral weathering govern the water chemistry. The water chemistry in the con ned aquifer is regulated by weathering of silicate and carbonate minerals and regional ow.

Recovering energy from waste offers dual benefits – a) improved waste management, and b) provision of reliable energy to households, institutions and commercial entities. In this report, we present a socioeconomic assessment of three energy business models (briquette manufacturing, on-site (public toilet) energy generation, and agro-waste electricity generation) based on feasibility studies carried out in the city of Kampala, Uganda. We assess the potential economic, environmental and social impacts of waste-to-energy business models taking into consideration a life cycle of emissions to provide decision makers with the overall costs and benefits of the models to society versus a business-as-usual scenario.

Phosphorus (P) is a critical, geographically concentrated, nonrenewable resource necessary to support global food production. In excess (e.g., due to runoff or wastewater discharges), P is also a primary cause of eutrophication. To reconcile the simultaneous shortage and overabundance of P, lost P flows must be recovered and reused, alongside improvements in P-use efficiency. While this motivation is increasingly being recognized, little P recovery is practiced today, as recovered P generally cannot compete with the relatively low cost of mined P. Therefore, P is often captured to prevent its release into the environment without beneficial recovery and reuse. However, additional incentives for P recovery emerge when accounting for the total value of P recovery. This article provides a comprehensive overview of the range of benefits of recovering P from waste streams, i.e., the total value of recovering P. This approach accounts for P products, as well as other assets that are associated with P and can be recovered in parallel, such as energy, nitrogen, metals and minerals, and water. Additionally, P recovery provides valuable services to society and the environment by protecting and improving environmental quality, enhancing efficiency of waste treatment facilities, and improving food security and social equity. The needs to make P recovery a reality are also discussed, including business models, bottlenecks, and policy and education strategies.