Wastewater - Turning Problem to Solution

Wastewater

Turning Problem to Solution

A Rapid Response Assessment

© 2023 United Nations Environment Programme

ISBN: 978-92-807-4061-5 Job number: DEP/2559/NA DOI: https://doi.org/10.59117/20.500.11822/43142

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Suggested citation: United Nations Environment Programme (2023). Wastewater – Turning Problem to Solution . A UNEP Rapid Response Assessment. Nairobi. DOI: https://doi.org/10.59117/20.500.11822/43142

Production: Nairobi, Kenya URL: https://wedocs.unep.org/20.500.11822/43142

This is a flagship product of the Global Wastewater Initiative

Acknowledgements

Supervision and coordination: Leticia Carvalho, Tessa Goverse, Heidi Savelli-Soderberg, Alex Pires, Riccardo Zennaro, and Avantika Singh and Josephine Nduguti (United Nations Environment Programme [UNEP])

Project management: Kristina Thygesen (GRID-Arendal)

Editors: Emily Corcoran, Elaine Baker, Kristina Thygesen (GRID-Arendal)

Contributing authors: Aviad Avraham (Ben-Gurion University of the Negev, Israel) Elaine Baker (GRID-Arendal) Roy Bernstein (Ben-Gurion University of the Negev, Israel) Christopher Corbin (UNEP/Cartagena Convention Secretariat) Emily Corcoran (GRID-Arendal, Consultant) Daniel Ddiba (Stockholm Environment Institute) Linus Dagerskog (Stockholm Environment Institute)

Tim Fettback (HafenCity University, Hamburg) Lüder Garleff (Hamburg Wasser, Hamburg)

Amit Gross (Ben-Gurion University of the Negev, Israel) Hadeel Hosney (IHE Delft Institute for Water Education) Edward Jones (Faculty of Geosciences, Utrecht University) Olfa Mahjoub (National Research Institute for Rural Engineering, Water and Forests, Tunisia) Bistra Mihaylova (Women Engage for a Common Future) Pedro Moreo (Caribbean Regional Fund for Wastewater Management (Phase 2) Project Coordinator) Charles Muhamba (Bremen Overseas Research & Development Association Tanzania) Alex Pires (UNEP) Manzoor Qadir (United Nations University Institute for Water, Environment and Health) Pierre van Rensburg (City of Windhoek) Arnold Schäfer (Hamburg Wasser, Hamburg) Hendrik Schurig (Hamburg Wasser, Hamburg) Prithvi Simha (Swedish University of Agricultural Sciences) Avantika Singh (UNEP) Florian Thevenon (United Nations Human Settlements Programme) Kristina Thygesen (GRID-Arendal) Sarantuyaa Zandaryaa (United Nations Educational, Scientific and Cultural Organization) Riccardo Zennaro (UNEP)

Layout: GRID-Arendal

Cartographers: Studio Atlantis, Kristina Thygesen

Reviewers: Tessa Goverse, Helene van Rossum, Nina Raasakka, Naomi Montenegro Navarro, Claire Thiebault, Lis Bernhardt (UNEP); Tatjana Hema (UNEP Barcelona Convention); Mahesh Pradhan (UNEP Coordinating Body on the Seas of East Asia); Una Harcinovic (World Business Council for Sustainable Development); Aslıhan Kerç (Turkish Water Institute – SUEN); Cecilia Tortajada (National University of Singapore); Rodrigo Riquelme, Pedro Moreo (Inter-American Development Bank).

Project support: Carina Thomassen (GRID-Arendal), Claire Rumsey (GRID-Arendal, Consultant)

Cover photos: ©istock/narvikk, ©iStock/Riccardo Lennart Niels Mayer, ©iStock/jonathanfilskov-photography (back)

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Glossary Biosolids – Sewage sludge, adequately treated, processed and applied as fertilizer to improve and maintain productive soils and stimulate plant growth (World Water Assessment Programme [WWAP] 2017). Blended finance – Blended finance is the strategic use of development finance for the mobilization of additional finance towards sustainable development in developing countries. Blended finance attracts commercial capital towards projects that contribute to sustainable development, while providing financial returns to investors (Organisation for Economic Co-operation and Development [OECD] n.d.). Circular economy – A circular economy offers an alternative economic model, whereby natural resources, including water sources, are kept at their highest value, for as long as possible. Circularity thinking provides a framework to develop comprehensive strategies for water management within a circular economy (United Nations Environment Programme 2019). De facto reuse – Where both treated and untreated wastewater can be used unintentionally where wastewater is incidentally present in a water supply (Jones et al. 2021). Direct potable reuse (DPR) – The injection of high-quality reclaimed water directly into the potable water supply distribution system, either upstream or downstream of the water treatment plant (i.e. without the use of an environmental buffer) (International Organization for Standardization [ISO] 2018). Domestic wastewater – Composed of black water, grey water and potentially other types of wastewater deriving from household activities in residential settlements (WWAP 2017). Emerging pollutants – Also referred to as contaminants of emerging concern, emerging pollutants are defined as “any synthetic or naturally-occurring chemical or any microorganism that is not commonly monitored or regulated in the environment with potentially known or suspected adverse ecological and health effects” (United Nations Educational, Scientific and Cultural Organization [UNESCO] 2015). Indirect potable reuse (IPR) – Augmentation of natural sources of drinking water (such as rivers, lakes, aquifers) with reclaimed water, followed by an environmental buffer that precedes drinking water treatment (ISO 2018). Industrial reuse – The reuse of industrial wastewater or the reuse of municipal wastewater to satisfy industrial water requirements (ISO 2018).

example energy production, mining, textiles, steel works, etc.) (WWAP 2017).

Municipal wastewater – Wastewater that comes from urban domestic and commercial sources, and any parts of industry or urban agriculture that are connected to the municipal sewers networks. Nature-based solutions – Actions to protect, conserve, restore, sustainably use and manage natural or modified terrestrial, freshwater, coastal and marine ecosystems, which address social, economic and environmental challenges effectively and adaptively, while simultaneously providing human well-being, ecosystem services, resilience and biodiversity benefits (UNEP/EA.5/Res.5).

Non-potable reuse – Use of reclaimed water not meeting drinking water standards for non- potable purposes (ISO 2018).

Non-potable water – Water that has not been treated to drinking water standards, but that may be considered safe for other uses. Non-potable uses include toilet flushing, irrigation, industrial uses or other non-drinking water purposes. Implementing a non-potable water-use system would require separate water distribution and plumbing systems (Metropolitan Council n.d.).

Planned reuse – Where treated or untreated wastewater is intentionally used (Jones et al. 2021).

Potable reuse – Use of high-quality reclaimed water as a water source for drinking water treatment and supply (ISO 2018).

Potable water – Water that has been treated sufficiently to meet or exceed drinking water standards and is considered safe for human consumption. Potable water uses include drinking, bathing/showering, food preparation, dishwashing and clothes washing (Metropolitan Council n.d.). Preliminary treatment – Removal of wastewater constituents such as rags, sticks, floatables, grit and grease that may cause maintenance or operational problems during the treatment operations and processes (WWAP 2017). Primary treatment – Removal of a portion of the suspended solids and organic matter from the wastewater, which can or cannot include a chemical step or filtration (WWAP 2017). Reclaimed water/recycled water/water reuse – Wastewater that has been treated to meet a specific water quality standard (fit for purpose) corresponding to its intended use (ISO 2018). Secondary treatment – Removal of biodegradable organic matter (in solution or suspension), suspended solids, and nutrients (nitrogen, phosphorus or both) (WWAP 2017).

Industrial wastewater – Water discharged after being used in or produced by industrial production processes (including, for

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Sludge – Residual nutrient-rich organic material, whether treated or untreated, from urban wastewater treatment plants (WWAP 2017).

from commercial establishments and institutions, including hospitals; industrial effluent, stormwater and other urban run-off; agricultural, horticultural and aquaculture effluent or run-off (adapted from Raschid-Sally and Jayakody 2008). Wastewater reuse – The practice of using untreated, partially treated or treated wastewater for resources including potable and non-potable water, irrigation water, nutrients, energy and heat value. Safe wastewater reuse is when the wastewater has been subjected to the appropriate level of treatment required to reach the quality standard for the intended purpose. Wastewater treatment – A process, or sequence of processes, that removes contaminants from wastewater so that it can be either safely used again (fit-for-purpose treatment) or returned to the water cycle with minimal environmental impacts. There are several levels of water treatment, the choice of which is dependent on the type of contaminants, the pollution load and the anticipated end use of the effluent (WWAP 2017).

Sustainable agriculture – To be sustainable, agriculture must meet the needs of present and future generations while ensuring profitability, environmental health and social and economic equity. Sustainable food and agriculture contribute to all four pillars of food security – availability, access, utilization and stability – and the dimensions of sustainability (environmental, social and economic) (Food and Agriculture Organization of the United Nations [FAO] n.d.). Tertiary treatment – Removal of residual suspended solids (after secondary treatment), further nutrient removal and disinfection (WWAP 2017). Wastewater – A combination of one or more of: domestic effluent consisting of black water (excreta, urine and faecal sludge) and grey water (kitchen and bathing wastewater); water

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Acronyms and abbreviations

AMR ARB ARG(s)

Antimicrobial resistance Antibiotic resistant bacteria Antibiotic resistance gene(s) Convention on Biological Diversity Conference of the Parties United Nations, Department of Economic and Social Affairs Decentralized wastewater treatment system Direct potable reuse European Investment Bank European Union Food and Agriculture Organization of the United Nations Gram The Global Environment Facility Caribbean Regional Fund for Wastewater Management (Phase 2) Greenhouse gas(es) Gigawatt hour Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services Intergovernmental Panel on Climate Change Indirect potable reuse International Centre for Water Security and Sustainable Management International Water Association International Water Management Institute Integrated water and wastewater management Potassium kilogram Kilowatt hours Cubic metres Millennium Development Goal(s) Milligram Million joules Nitrogen Nature-based solutions The Organization for Economic Cooperation and Development Phosphorus Sustainable Development Goal(s) United Nations Human Settlements Programme Coordination mechanism comprising United Nations entities (Members) and international organizations (Partners)

CBD COP DESA DEWATS DPR EIB EU FAO g GEF CReW+ GHG(s) GWh IPBES IPCC IPR i-WSSM IWA IWMI IWWM K kg kWh m 3 MDG(s) Mg MJ N NBS OECD P SDG(s) UN-Habitat UN-Water

working on water and sanitation issues United Nations Environment Programme United Nations Educational, Scientific and Cultural Organization World Business Council for Sustainable Development

UNEP UNESCO WBCSD

WHO WTO WWAP

World Health Organization World Trade Organization World Water Assessment Programme

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Contents Acknowledgements .............................................................................................................................................................................................. iii Glossary ................................................................................................................................................................................................................ iv Acronyms and abbreviations................................................................................................................................................................................ vi List of figures ...................................................................................................................................................................................................... viii List of tables ......................................................................................................................................................................................................... ix List of boxes ........................................................................................................................................................................................................... x List of case studies .............................................................................................................................................................................................. xi Foreword .............................................................................................................................................................................................................. xii Executive summary ............................................................................................................................................................................................ xiv Part 1: Background and purpose 1 A decade on from Sick Water?............................................................................................................................................................................... 1 Why addressing wastewater is still urgent .......................................................................................................................................................... 8 Why focus on wastewater resource recovery and reuse?.................................................................................................................................. 13 Part 2: The potential for wastewater resource recovery and reuse 19 Wastewater in numbers ...................................................................................................................................................................................... 19 Wastewater in the circular economy................................................................................................................................................................... 23 What are the resources that can be recovered from wastewater?.................................................................................................................... 26 Safe reusable water....................................................................................................................................................................................... 29 Nutrient recovery ................................................................................................................................................................................................. 35 Energy recovery ................................................................................................................................................................................................... 41 Other potential products from wastewater and their applications................................................................................................................... 44 Persistent barriers and concerns to wastewater reuse and recovery............................................................................................................... 46 Inadequate political support or lack of priority setting in the political arena ............................................................................................. 48 Governance, institutional and regulatory barriers ....................................................................................................................................... 49 Insufficient data and information ................................................................................................................................................................. 49 Inadequate financing ..................................................................................................................................................................................... 51 Low social and cultural acceptance, including religious reasons .............................................................................................................. 51 Limited human and institutional capacity.................................................................................................................................................... 54 Environmental and human health concerns................................................................................................................................................. 55 Contaminants of concern ............................................................................................................................................................................. 59 Part 3: The solution – Optimizing wastewater resource recovery and preventing pollution 61 Action areas.......................................................................................................................................................................................................... 63 Action area 1: Reduce the volume of wastewater produced ...................................................................................................................... 63 Action area 2: Prevent and reduce contamination in wastewater flows ................................................................................................... 66 Action area 3: Sustainably managing wastewater for resource recovery and reuse ................................................................................ 69 The building blocks for systems change ........................................................................................................................................................... 81 Effective and coherent legislation and governance .................................................................................................................................... 82 Mobilize adequate and sustained investment ............................................................................................................................................. 86 Enhancing human, technical and institutional capacity at all levels (local to global) .............................................................................. 90 Technical and social innovation ................................................................................................................................................................... 91 Stronger data and information ..................................................................................................................................................................... 92 Increase communications, awareness and accountability......................................................................................................................... 93 Part 4: Conclusions 97

References ........................................................................................................................................................................................................... 99

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List of figures

Figure 0.1 Figure 0.2 Figure 1.1 Figure 1.2 Figure 1.3 Figure 1.4 Figure 2.1 Figure 2.2 Figure 2.3 Figure 2.4 Figure 2.5 Figure 2.6 Figure 2.7 Figure 2.8 Figure 2.9 Figure 2.10 Figure 2.11 Figure 2.12

The potential wastewater available for resource recovery and reuse ....................................................................................... xv Environmental implications and intervention points ................................................................................................................ xvii Progress since 2010 against the key messages from Sick Water?.............................................................................................. 3 Key areas of progress against the (a) short-term actions and (b) long-term actions recommended in the 2010 Sick Water? report .................................................................................................................................................................................. 4 Global water stress by country in 2020 and 2040 ...................................................................................................................... 11 Wastewater, SDG 6 and interdependencies across the SDGs ................................................................................................... 12 Municipal wastewater production across regions in 2015 and predicted until 2050 .............................................................. 19 Estimates of country level (a) domestic and manufacturing wastewater production (m 3 /year per capita), (b) collection (%), (c) treatment (%), and (d) reuse (%) at the country scale, based on 2015 data and reproduced from Jones et al. (2021)................................................................................................................................................................ 21 Circularity in wastewater management ...................................................................................................................................... 24 Schematic of the Billund Biorefinery ............................................................................................................................................ 25 Potential resources that can be recovered from wastewater..................................................................................................... 27 Increasing value propositions related to wastewater treatment based on increasing investments and cost recovery potential .................................................................................................................................................................. 28 Illustration of terms for wastewater and its reuse ..................................................................................................................... 30 The process for recovering wastewater as NEWater in Singapore ........................................................................................... 31 Changes in Windhoek water supply to increase the reuse of treated wastewater as a result of a period with drought .......... 32 Reuse of nutrient-rich treated water for food self-sufficiency in the Middle East and North Africa region ............................. 34 The potential for human urine-derived nutrients to meet global nitrogen and phosphorus demand in agriculture .............. 36 Global potential of nutrients embedded in wastewater at the global level in 2015, and their potential to offset the global fertilizer demand in agriculture, as well as to generate revenue..................................................................................... 37 Application of plant nutrients from chemical fertilizers compared to nutrients from human excreta .................................... 38 Potential for energy production from wastewater based on the 2015 wastewater production data and scenarios over coming decades for the years 2030, 2040 and 2050, based on the expected increase in wastewater volume and assuming full energy recovery from the wastewater........................................................................................................... 39 The barriers and concerns relating to wastewater resource recovery and its safe reuse ....................................................... 42 Availability of data across the wastewater chain including the number of countries for which wastewater data were available; and the percentage of population coverage (i.e. the proportion of the global population for which wastewater data were available).................................................................................................................................................. 47 Sanitation and waterborne antimicrobial resistance exposure risk........................................................................................... 50 Level of effectiveness and relative cost of various treatment methods for the removal of antibiotics .................................. 57 Trends in per capita water consumption in Singapore .............................................................................................................. 65 Trends in urbanization, annual water use and the annual quantity of wastewater discharged in China. Despite urbanization increasing, water use has decreased (top) and total wastewater discharge has, between 2014 and 2016, also now started to decrease (bottom) ............................................................................................................................. 65 Laufen’s Save! toilet has an EOOS “Urine Trap” to separately collect human urine at source ................................................ 68 Water collection, treatment and reuse by region......................................................................................................................... 69 A generalised schematic of typical wastewater treatment stages and opportunities for resource recovery......................... 70 Expansion in wastewater treatment capacity required by 2030 to achieve SDG 6.3 for the top 30 wastewater producing countries ..................................................................................................................................................................... 72 Finding the optimal solution to treating wastewater for resource recovery.............................................................................. 73 Dissolved organic carbon content and total suspended solids concentrations before and after treatment in the wastewater treatment plant, as compared with the Israeli Government guidelines for unlimited irrigation ........................... 76 Nature-based solutions systems for wastewater treatment ..................................................................................................... 78 Six building blocks to support wastewater resource recovery and reuse ................................................................................. 81 The three types of voluntary commitments under the United Nations Water Action Agenda ................................................. 84 The action framework and commitment mechanism of the Wastewater Zero Commitment Initiative ................................... 85 A timeline of the development of regulation, criteria and guidelines from 1918 to 2020......................................................... 94 Timeline of significant events and initiatives relevant to development of wastewater resource recovery and reuse since 2010 ........................................................................................................................................................................... 97

Figure 2.13 Figure 2.14

Figure 2.15 Figure 2.16

Figure 2.17 Figure 2.18 Figure 3.1 Figure 3.2

Figure 3.3 Figure 3.4 Figure 3.5 Figure 3.6

Figure 3.7 Figure 3.8

Figure 3.9 Figure 3.10 Figure 3.11 Figure 3.12 Figure 3.13 Figure 4.1

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List of tables

Table 1.1

The connection between sustainable wastewater management, resource recovery and reuse, with key societal concerns ................................................................................................................................................................................ 14 Composition of different fractions of household wastewater produced per person and year ................................................... 37 Annual quantity of nutrients in human excreta in Burkina Faso with the corresponding quantity of urea and NPK (15:15:15) (the most common fertilizers in Burkina Faso) ................................................................................................... 39 Overview of other resources that can be recovered from wastewater, with examples of locations where implementation has been done at full scale .................................................................................................................................. 45 Different processes for black wastewater treatment and associated products ......................................................................... 74 Possible actions to develop effective and coherent legislation and governance ....................................................................... 83 Possible actions to mobilize adequate and sustained investment . ............................................................................................. 87 Possible actions to enhance human, technical and institutional capacity ................................................................................. 90 Possible actions to encourage technical and social innovation .................................................................................................. 91 Possible actions to deliver stronger data and information ........................................................................................................... 92

Table 2.1 Table 2.2

Table 2.3

Table 3.1 Table 3.2 Table 3.3 Table 3.4 Table 3.5 Table 3.6

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List of boxes

Box 1 Box 2 Box 3 Box 4 Box 5 Box 6 Box 7 Box 8 Box 9 Box 10

What is wastewater? .............................................................................................................................................................................. 8 The Sustainable Development Goals and wastewater ........................................................................................................................ 12 Wastewater reuse and climate change................................................................................................................................................ 16 Wastewater data and statistics............................................................................................................................................................ 22 Overview of the potential for resource recovery from wastewater.................................................................................................... 26 Health implication for children exposed to the use of untreated wastewater ................................................................................... 56 Wastewater undermining the resilience of coral reefs – an ecosystem on the brink ....................................................................... 58 The EU Green Deal and wastewater management for reuse ............................................................................................................. 62 Note on wastewater treatment statistics ........................................................................................................................................... 70 The United Nations Water Action Agenda .......................................................................................................................................... 84

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List of case studies

Case study 1 Case study 2 Case study 3 Case study 4 Case study 5 Case study 6 Case study 7 Case study 8 Case study 9 Case study 10 Case study 11 Case study 12 Case study 13 Case study 14 Case study 15 Case study 16 Case study 17 Case study 18

An innovative circular wastewater treatment plant conversion – Billund Biorefinery, Billund, Denmark

25 32 34 39

Direct potable reclamation in Windhoek, Namibia

Reuse of nutrient-rich agricultural drainage water for food self-sufficiency in Fayoum, Egypt

Sustainable productive sanitation solutions in rural Burkina Faso Producing urine-based fertilizer on the island of Gotland, Sweden 40 Resource-efficient decentralized wastewater treatment systems in Dar es Salaam, United Republic of Tanzania 43 Large-scale centralized wastewater treatment as an energy source in Hamburg, Germany 44 Social barriers to urine recycling in decentralized sanitation systems 52 When farmers’ acceptance is challenged by consumers’ buy-in and the quantity and quality of the effluents, Ouardanine, Tunisia 53 Reuse of treated municipal wastewater for industry and ecosystem health in Lingyuan City, China 58 Urine separation – Alkaline dehydration in practice in Malmö, Sweden 68 The challenges of keeping up with the demands of a growing city – expanding wastewater treatment capacity in Delhi, India 75 The London Super Sewer – Improving collection of wastewater 75 Advanced wastewater treatment for reuse in small off-grid settlements in the Israeli Negev desert 76 Nature-based solutions to treat wastewater for resource recovery and reuse – the Solomon Islands Urban Water Supply and Sanitation Sector Project 79 Sustainable wastewater and nutrient management in rural Georgia to address pollution in the Black Sea 80 The Wastewater Zero Commitment Initiative, Global 85 Financing wastewater treatment and reuse in Latin America and the Caribbean 2019–2024. Part of the Global Environment Facility Caribbean Regional Fund for Wastewater Management (GEF CReW+) Project 88 Tariff reform to support wastewater treatment and reuse in Colombia, 2020–2023. Part of the GEF CReW+ Project 89 NEWBrew – Raising awareness with a beer from 100% recycled wastewater, Singapore 95

Case study 19 Case study 20

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Foreword

In 2010, the United Nations Environment Programme (UNEP), the United Nations Human Settlements Programme (UN-Habitat) and GRID-Arendal published a report entitled Sick water? The central role of wastewater management in sustainable development – A rapid response assessment. The report called for a greater focus on the intelligent management of wastewater, which recognizes its potential in contributing to sustainable development. This approach involves recovering and safely reusing the valuable ingredients that make up wastewater, such as nutrients, energy and water. Recovering these resources can deliver multiple co-benefits, such as reduced dependence on synthetic fertilizers, which constitute up to 25 per cent of the global nitrogen and phosphorus demand in agriculture; diversified energy production, which can provide electricity for around half a billion people per year; and increased water security, carrying the potential to irrigate around 40 million hectares. More than a decade later, UNEP has recognized that we are facing a triple planetary crisis of climate change, biodiversity loss and rampant pollution. This crisis is undermining nature’s ability to provide the ecosystems services that in turn support human and non-human well-being. Population growth and urbanization are also placing a huge strain on finite water sources, with a third of the global population already living in water scarce regions with demand set to intensify. Therefore, it is an absolute priority to accelerate action to beat wastewater pollution while harnessing its underutilized potential. There has been some progress: We invite you to take a close look at the 20 case studies presented in this report. You will find amazing examples of solutions from every corner of our world, from the Caribbean to China, from Solomon Islands to Tunisia, from Singapore to Colombia, from India to Namibia, from London to Burkina Faso, from Black Sea to Sweden, from

Denmark to Egypt, and so on. These case studies give real world examples of solutions that are already bringing about the changes we need. But these changes are not happening at the speed or scale needed, creating serious risks for ecosystems and human health, as well as the resilience of societies. In many parts of the world, even the basic treatment and utilization of wastewater remains a significant challenge. In France, for example, only 0.1 per cent of treated wastewater produced is reused. The “Wastewater – Turning Problem to Solution” report challenges the view that wastewater is an end-of-pipe problem to be disposed of and, instead, repositions it as a circular economy opportunity: a renewable and valuable resource to be conserved and sustainably managed with the potential to drive new jobs and revenue streams. We are very pleased to publish this report, whose authors have defined three key areas for action and six necessary building blocks to help policy and decision makers lead transformational change in sustainable wastewater management. The three actions call for reducing how much wastewater we produce, being more careful about what goes into the water we use, and considering how to better collect and treat wastewater so that we can recover and safely use its valuable resources. The building blocks focus on the social, cultural and behavioural changes that will need to happen in order for actions to succeed: ensuring an enabling, coherent governance and legislative framework; mobilizing investment in infrastructure and the human and institutional capacity that is needed; encouraging technical and social innovation; improving data feedback for iterative adaptation; and strengthening communication and awareness to build understanding and trust to help change our behaviours and attitudes to water usage.

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It is our hope that this publication will help set in motion a shared global vision that recognizes the inherent value of wastewater as a resource. Action is needed in a whole-of society approach recognising that the most appropriate solution, or combination of solutions for recovering resources from wastewater will depend upon economic, environmental, social and cultural contexts. We invite you to use this publication to elevate to the political agenda the urgent need for the safe recovery of resources from wastewater. For us, it is clear that the transition will involve incremental actions, learning, adapting and innovating. We are confident that you will find this report very valuable in putting us on a pathway to success.

Leticia Carvalho Head of Marine and Freshwater Branch, United Nations Environment Programme

Peter T. Harris Managing Director, GRID-Arendal

The “Wastewater – Turning Problem to Solution” report challenges the view that wastewater is an end-of-pipe problem to be disposed of and, instead, repositions it as a circular economy opportunity.

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Executive summary

processes so that we can safely recover the valuable embodied products. But negative public perceptions and concerns – about environmental and health risks – still surround wastewater resource recovery and reuse. There is a need for inspired critical thinking to transform the perception of wastewater from being an end-of pipe pollution problem to a flourishing resource. To change how water is used, collected, treated and valued will require policies and actions that are inclusive and equitable. It will also need appropriate financing and capacity-building. tackling the triple planetary crisis of climate, nature and pollution. Wastewater reuse needs to be a key component of the United Nations Water Action Agenda. Promoting wastewater as a resource requires raising awareness of the potential benefits of reuse. Leaving this issue behind will seriously undermine progress towards achieving the Sustainable Development Goals (SDGs), as the reuse of water and other resources from wastewater can make an important contribution to food and water security, with the potential to provide alternative water resources, valuable nutrients, create new jobs, develop new energy streams and ensure a clean, healthy and sustainable environment. The issues Water is central to life, biodiversity, ecosystem integrity, food and energy production, yet decades of mismanaging our water resources through overconsumption, pollution and insufficient recycling have led to a global water crisis. This is exacerbated by climate change impacts, population growth and urbanization. Sustainable water management is critical and must include how water is managed once it has been used. Wastewater volumes are continually increasing, and despite some progress in treatment and reuse over the past decade, untreated wastewater remains a significant global challenge – around half of the world’s wastewater still enters the environment without adequate treatment. In 2013, it was estimated that the annual production of wastewater, primarily from municipal sources, to be 330 billion m 3 . Subsequent estimates suggest this had risen to 360–380 billion m 3 /year by 2015. This is five times the volume of water passing over Niagara Falls annually. Elevating the reuse of resources from wastewater in the international policy agenda is critical to

More than 10 years have passed since the release of the report Sick Water? The Central Role of Wastewater Management in Sustainable Development – A Rapid Response Assessment report (“the Sick Water? report”), and despite some progress, significant amounts of wastewater are still being released untreated into the environment. Untreated wastewater is one of the key drivers of biodiversity loss and a major threat to human health, particularly affecting the most vulnerable people and ecosystems. But when adequately treated, wastewater can become a valuable resource. This new report “Wastewater – Turning Problem to Solution” examines solutions to the challenges in realising sustainable wastewater management and capitalising on the opportunities for resource recovery and reuse. The report considers how to develop and extend these solutions to locations where improved wastewater management is desperately needed. Key messages people produce every day, no matter who or where they are. It is produced in large quantities and then forgotten about. Ignoring this important resource would be a mistake that undermines our reliance on finite water supplies. It is time to transform how we see wastewater, from a smelly and dangerous source of pollution, improperly managed, having severe negative impacts on environmental and human health, to a well-managed and valued resource carrying huge potential as a source of clean water, energy, nutrients and other materials. This resource could help provide sustainable solutions to address the worsening environmental and societal crises, many rooted in water shortages, that contribute to food insecurity and undermine ecosystems. Only 11 per cent of the estimated total of domestic and industrial wastewater produced is currently being reused. Out of sight cannot be out of mind when it comes to wastewater. Wastewater is used water, something Given the world’s worsening water and food and energy security crises, we cannot afford to waste a drop. The untapped potential for wastewater reuse is around 320 billion cubic metres (m 3 ) per year, with the potential to supply more than 10 times the current global desalination capacity. Unlocking the potential of wastewater requires rigorous collection and treatment

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Population growth is a major driver in increasing wastewater volumes – with the world’s population estimated to increase by another 2 billion to almost 10 billion by 2050. This growth is projected to occur mostly in urban agglomerations in developing countries – populations that are already underserved by adequate water supply and wastewater treatment systems. The volume of wastewater from domestic and municipal sources is estimated to rise to 470–497 billion m 3 /year by 2030, representing a 24–38 per cent increase in the volume of wastewater produced by the time the SDGs expire. Realizing human rights and global political ambitions with regards to water requires fundamental and systemic changes to see wastewater as a resource. Improper handling of wastewater disproportionately affects vulnerable groups, especially children and women. Due to gendered labour division, women are often most affected by the lack of wastewater treatment and consequent poor water quality. They are the most likely to be in contact with faeces and food as primary carers, increasing health risks to themselves and their families.

Safe and appropriate wastewater management for resource recovery and reuse goes beyond achieving water security, with potential co-benefits including improved environmental health, human health and well being, protecting biodiversity, reducing dependence on synthetic fertilizers, and diversifying energy production and economic opportunity. Additionally, an inclusive approach to water and wastewater management results in societal benefits, especially among women, ensuring they can easily access safe water and have more time to earn income. Despite several successful wastewater reuse applications in many countries, persistent barriers and concerns linger, continuing to limit the widespread implementation of water reuse at scale. These barriers and concerns include: • Inadequate political support or lack of priority setting in the political arena – wastewater resource recovery and reuse is not sufficiently prioritized in the political discourse. • Governance, institutional and regulatory barriers – where there are policies for resource recovery and reuse from wastewater streams, there are often inconsistent or competing policy objectives and low levels of implementation, with weak compliance and enforcement. • Insufficient data and information – current deficits in data availability and accessibility relating to wastewater resource recovery and reuse, and lack of gender disaggregated data make it difficult to assess impacts, target actions and track progress in implementation. • Inadequate financing – there is a practical need to close the water loop, but sustainable investment will only occur if it is economically viable to treat and reuse wastewater. Innovative approaches to financing such as blended finance approaches, cost recovery and other incentives need to be implemented to fund improved collection and treatment, immediately and at scale. • Low social and cultural acceptance, including for religious reasons – familiarity, awareness and trust are required to tackle the negative perceptions of wastewater and bring about the required behaviour changes, recognizing there are different implications for different stakeholder groups. • Limited human and institutional capacity – in many cases, lack of capacity is hindering wastewater management, resource recovery and reuse, including for monitoring and data management.

Wastewater production, collection, treatment and reuse Billions of cubic metres Unlocking the potential of wastewater

2030 projection and potential to reach SDG 6.3

470

2015

360

357

225

188

Potential for substantial increase in recycling and safe reuse globally

40

The untapped potential for wastewater reuse is around 320 billion cubic metres per year, with the potential to supply more than 10 times the current global desalination capacity

Proportion to be treated to achieve the SDG target for halving the amount of untreated wastewater

Collected and treated Collected, treated, and reused

Production

Collected but not treated

Source: Qadir et al . 2020; Jones et al . 2021

Figure 0.1: The potential of wastewater as a resource.

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• Environmental and human health concerns, and potential risks from pollutants, pathogens, antimicrobial resistance (AMR) and contaminants of concern – including emerging and persistent pollutants and microplastics that may still be present in reclaimed resources and recycled water. The solution As an integral part of sustainable water management, wastewater resource recovery and safe reuse can be a consistent and effective way to address a range of sustainable development issues: from water scarcity to pollution, climate change adaptation and resilience, energy security, sustaining food systems, and human and ecosystem health. This central role of wastewater in securing our common future was recognized in target 6.3 of the SDGs, calling for improved water quality, including reducing the proportion of untreated wastewater, and increasing recycling and safe reuse. The transformation needed to move away from seeing wastewater as a waste management issue to a valued resource is increasingly urgent. This can only be delivered by combining technical solutions with capacity development, mobilizing adequate resources, and a clear, shared strategy to create the social, cultural, regulatory and institutional shifts that can develop new values and norms in society. It is possible to recover valuable resources, such as nutrients, energy and water, when appropriate wastewater collection, treatment and management are in place. A key requirement for any sustainable resource recovery and reuse from waste streams is to ensure that it is safe for people and the environment. When fit for purpose, these resources can deliver multiple co-benefits, such as: reduced dependence on synthetic fertilizers (i.e. up to 25 per cent of the global nitrogen and phosphorus demand in agriculture could be met by recycling human urine-derived nutrients); diversification of energy production (i.e. providing electricity for around half a billion people per year, based on potential methane production); and increased water security (i.e. the untapped potential for wastewater reuse is around 320 billion m 3 /year, with the potential to irrigate around 40 million hectares. Noting the continued relevance of the recommendations made in the 2010 Sick Water? report, this new report examines the challenges to realizing the benefits and opportunities of wastewater resource recovery and reuse.

It draws on case studies to explore potential interventions and approaches to overcome these challenges. It defines three key action areas and identifies six building blocks to maximize the opportunities of wastewater resource recovery and safe reuse. The aim is to inspire policymakers and decision makers to be proactive in leading transformational change in sustainable wastewater management, providing options for solutions. The right solution, or combination of solutions, will depend on the local or regional circumstance, and must fit the economic, environmental, social and cultural contexts. There are many excellent experiences to learn from, to realize the opportunities of wastewater reuse, some of which are provided as case studies in this report. 1. Reduce the volume of wastewater produced Freshwater resources must be used more responsibly. Reducing water consumption will lower the wastewater volumes produced, making the task of recovering and reusing wastewater more achievable, by reducing energy requirements and the cost of collection and treatment. It will also reduce pollution risks to people and nature. 2. Prevent and reduce contamination What goes in = what comes out. More attention must be paid to what is put into water when it is used, and where feasible, separating and eliminating compounds at source before they enter the wastewater flow. By reducing and restricting the contaminants of concern in our water (e.g. pharmaceutical compounds, chemical and synthetic compounds, microplastics or nanoparticles), it is easier and cheaper to treat, and safer to reuse the resources in wastewater or to release treated water back to the environment. Collection is a prerequisite to treatment. There are many solutions for the collection and treatment of wastewater to recover resources of appropriate quality standards, depending on its application. Investments are needed to expand the capacity for wastewater collection and treatment that includes the recovery of resources for reuse. Investment is also needed to address the neglect or insufficiency of existing wastewater management facilities to ensure they are fit for purpose. These action areas must be addressed in conjunction with each other and at multiple levels. As with the three action areas, successfully expanding the reuse of wastewater will require urgent progress on the following The three key action areas: 3. Sustainably manage wastewater for resource recovery and reuse

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