Changing times for urban non-sewered sanitation

Internal view of the Lubigi Faecal Sludge and Wastewater Treatment Plant, Kampala, Uganda. © L Strande

Current professional interest in non-sewered sanitation builds on efforts over recent decades. Linda Strande reflects on the transformation of the agenda for urban areas.

In the 1980s and 1990s, water and sanitation development projects in low-income countries were mainly focused on drinking water provision. It was not until 2002 that access to basic sanitation was incorporated in the Millennium Development Goals (MDGs) target 7c, after the World Summit on Sustainable Development in Johannesburg. Meanwhile, in the United States, even with one quarter of the population being served by onsite sanitation, the US Environmental Protection Agency (EPA) did not acknowledge that such approaches could be a sustainable option until 2003 (with publication of its Voluntary National Guidelines For Management Of Onsite And Clustered (Decentralized) Wastewater Treatment Systems).

Furthermore, although these acknowledgements were made almost 20 years ago, non-sewered sanitation was, until quite recently, still widely considered globally to be a temporary solution, bridging a gap until sewers could be built. This is despite the fact that, in 2017, more than one third of the world’s population was served by non-sewered sanitation, and in low-income countries less than 10% of urban areas were served by sewers.

There were, however, some pioneers in various institutions who started in the 1980s and 1990s to think about alternatives to sewered sanitation for urban and peri-urban areas. They played a key role in setting a path. Through knowledge-sharing, education, and mentoring, they helped to galvanise the field and build a critical mass of engineers, practitioners, and scientists working on sanitation.

My own experience, starting graduate school in the late 1990s at the University of Washington in Seattle, was of having a passion to study possibilities for globally relevant, non-sewered sanitation. However, onsite sanitation was viewed as being temporary holes in the ground not worthy of attention, or research, or management. Engineers focused their work on sewer-based systems, and there were only a handful of universities that even had onsite sanitation included in their curriculum. Many people at the university really thought I was crazy to give a shit about such a topic! With little in the way of opportunities and funding to study non-sewered sanitation, my thesis projects were on the use of biosolids sludge in forestry and the fate of oestrogens in centralised, sewer-based treatment facilities.

But today, I am proud to be continuing the work of Sandec at Eawag, the Swiss Federal Institute of Aquatic Science and Technology, which has been addressing sanitation needs in low- and middle-income countries since the early 1980s, and faecal sludge management (FSM) since the 1990s.

The non-sewered landscape today

Since the wider recognition of the importance of sanitation, marked by the UN declaring 2008 as the ‘Year of Sanitation’, there has been a steady increase in commitment, uptake, implementation, and knowledge generation in non-sewered sanitation. Although it is never fast enough, views and attitudes are changing quite quickly, and the necessity to consider non-grid, small-grid and hybrid sanitation systems alongside sewerage systems is gaining recognition globally. One important driver has been the general increase in public awareness, which can lead to change through political pressure. This can be seen in popular press coverage of World Toilet Day, books such as Pipe Dreams: The Urgent Global Quest to Transform the Toilet, and even the Indian film Toilet: A Love Story.

There has been a rapid increase in evidence-based research and journal publications, and we are now able to obtain funding from national science foundations for our research. I can’t stress enough the importance of continuing to fill the knowledge gap and for practitioners and scientists to get information out there in a transparent fashion. Experience is worth nothing to others if it is not shared, and the knowledge of today will become outdated. This knowledge sharing has been greatly improved with networks such as SuSanA and the FSM Alliance.

Technology alone is not the solution, but through solution-oriented research, there are rapidly evolving technology developments along the entire service chain. Some even have the potential to alter the existing service chain, such as container-based sanitation, decentralised options, and innovations developed through the Bill & Melinda Gates Foundation ‘Reinvent the Toilet Challenge’. Off-grid solutions for Switzerland are now being researched in the Water Hub at Nest at Eawag, and our research experience in low-income countries is informing our work on blackwater.

In terms of resource recovery, we have greatly expanded the possibilities. These include energy as fuel and heat, food products such as animal fodder from plants, and protein production from black soldier flies, in addition to soil conditioners, fertiliser and water reclamation.

And, very importantly, curriculums have been, and are continuing to be, developed and implemented. Initiatives include the Global Sanitation Graduate School, and freely available online courses, such as the Sandec MOOC series, which has had more than 150,000 online learners. The result is an emerging new generation of students, practitioners and scientists who will be the future champions in developing and implementing sanitation solutions.

However, when you compare our scientific knowledge with the 100-plus years of research on activated sludge, non-sewered sanitation is still in its infancy. One important driver of research has been the acknowledgement that faecal sludge is different to wastewater and cannot simply be co-treated. We have learned a lot about characteristics, treatment technologies and dewatering mechanisms, but we still need improved knowledge of flow behaviour, redox conditions, nutrients, ions, stabilisation, particle size, extra-cellular polymeric substances, undigested plant fibres, and microbial community composition. The new book Methods of Faecal Sludge Analysis (Velkushanova et al 2021; IWA Publishing) will lead to more comparable results, and understanding the fundamentals of treatment mechanisms will be the basis to develop new and improved treatment technologies, and continue to adapt existing ones

We see also that many faecal sludge treatment facilities still operate without adequate operational or laboratory capacity. There is a need to develop monitoring possibilities, and to address the dynamic operation of treatment plants to account for fluctuating loadings, with simple, easy-to-measure parameters.

One future possibility could be to predict dewaterability based on a smartphone app that is built through a global database of pictures. In the future, we also need to focus more on dealing with all faecal sludge streams, and not to forget about liquid streams, supernatant and greywater.

Also, the World Health Organization (WHO) guidelines on sanitation and health published in 2018 propose technology levels in terms of established, transferring and emerging technologies, to support risk-based implementation and so get the fastest possible uptake of emerging knowledge. This was pioneered by the WASH R&D Centre and the eThekwini municipality in Durban, South Africa. So, we continue to need large-scale pilot research, with research institutions working together with government to scale up solutions.

Aiming for integration and inclusivity

Recognition of non-sewered sanitation has brought us a long way, with its incorporation in development agendas, national regulations and government agendas, and to more widespread implementation.

Under the MDGs, sanitation was defined as household-level access to a safe toilet. The growth in recognition of non-sewered sanitation has led to a paradigm shift in thinking in which just building and counting toilets is not enough. This is reflected in the Sustainable Development Goals (SDGs), which incorporate thinking of sanitation as more than access to toilets. Universal access to sanitation is not an urban-rural or rich-poor question. We see that citywide inclusive sanitation includes institutionalising a service delivery approach along the entire service chain, rather than just infrastructure provision. Also, public health has been brought into the conversation, considering entire neighbourhoods, and there are clear links between faecal contamination along with population density on long-term effects such as stunting, infant mortality, academic performance and economic impacts.

A number of initiatives have led us here, including those covering public health aspects of safely and unsafely managed excreta. These include the concept of the shit flow diagram that was developed in 2012 as part of the World Bank-funded 12-city study, sanitation safety planning developed by the WHO, and tools such as SaniPath developed at Emory University, as well as initiatives with business models and service provision.

But we still have far to go, and we should dream big. We should shoot for governments talking about planning for combined solutions for water, sanitation and solid waste, which are intrinsically linked, with all of the services being essential for the protection of public and environmental health and economic development. This requires a further paradigm shift – one entailing more sophisticated planning, increased inter-agency cooperation, and government leadership and commitment. But by breaking these silos, we can help overcome the institutional barriers necessary to recognise the co-benefits of integrated approaches. •

More information:

A Sanitation Journey – Principles, Approaches & Tools for Urban Sanitation, R Schertenleib et al, 2021.

Estimating safely managed sanitation in urban areas; lessons learned from a global implementation of excreta-flow diagrams, A Peal et al, Frontiers in Environmental Science, 31 January 2020.

Advancements in and Integration of Water, Sanitation and Solid Waste in Low and Middle Income Countries, AS Narayan et al, Annual Review of Environment and Resources 2021.

Predictive models using “cheap and easy” field measurements: Can they fill a gap in planning, monitoring, and implementing fecal sludge management solutions? BJ Ward et al, Water Research, 15 May 2021.

Dr Linda Strande is Senior Research Scientist at the Department Sanitation, Water and Solid Waste for Development at Eawag – Swiss Federal Institute of Aquatic Science and Technology