This year, the theme of WTD is 'sustainable sanitation and climate change', to call attention to the self-reinforcing relationship that exists between climate change (CC) and the sanitation service chain (SSC): as the SSC is vulnerable to CC, yet is also a significant contributor of pollution and greenhouse gases.
Naafs (2020) provides a great synthesis of the 4 key interactions between CC and the SSC, and the threats these pose to safe sanitation service provision, illustrated in figure 1.
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| Figure 1. Illustration of sanitation service chain and interaction with climate change (Naafs, 2020) |
The CC impacts addressed in points 1 & 2, are particularly threatening to the SSCs of urban slums in SSA:
The impacts of (1) water stress, drought and increased aridity, are creating a wave of rural-to-urban environmental refugees: increasing pressure on already overburdened urban sanitation services, and preventing increasingly vulnerable people from accessing safe, and dignified sanitation. So, whilst Naafs highlights these impacts in relation to the 'capture' stage of the SSC, I would argue the entirety of the SSC is affected in the context of urban SSA.
The impacts of (2) increased rainfall and flooding, disproportionately impact the urban poor because slums tend to sprawl into high-risk areas, such as wetlands, and low-elevation coastal zones, this is compounded by the high-density of insecure sanitation infrastructure, leading to a proliferation of faecal-environmental-oral contamination routes, and subsequent health risks.
I believe the solution may lie in Ecological Sanitation (EcoSan): a low-cost, community-based, sustainable sanitation alternative, which provides a promising ‘resource recovery’ solution to the sanitation issue in SSA, by harnessing the nutrient-rich resources of hygenised faeces and urine, as fertilisers in agricultural production, through a circular economy framework (Simha & Ganesapillai, 2017). Thus, creating a closed-loop, ecological cycle of nutrients and organic matter.
Some examples of EcoSan systems include:
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| Figure 2. (A) composting toilet - this demands a level of active waste treatment to effectively produce fertiliser; (B) biogas reactor - produces cooking gas that provides a more eco-friendly alternative to firewood; (C) fossa alterna or alternating pit - similar to a traditional pit latrine, however, waste is left to compost without active treatment, and can later be used as a fertiliser; (D) arborloo - waste is not extracted, rather, a tree (often carrying fruit) can be planted after composting period. (Andersson & Minoia, 2017) |
EcoSan produced human excreta-derived fertiliser (HEDF), provides a potential solution to the nutrients depletion of soils in SSA (Moya, 2019). HEDFs; improve soil structure; increase soil water holding capacity; reduce soil erosion; reduce pests and diseases; and neutralise soil toxins, resulting in greater crop yields (Nikiema et al., 2013). A study in Burkina Faso, found that HEDF crop yields were 30% higher, and the harvest period doubled, compared to chemical fertilisers. Moreover, vegetables produced using HEDFs were larger and ‘more beautiful’ which increased sales (Dagerskog et al., 2018). This increased agricultural productivity, and associated (economic) community development, would also decrease rural-to-urban migration: reducing pressure on urban sanitation infrastructures. The use of HEDFs also helps to mitigate public health risks, by reducing the pollution of surface and groundwater’s by untreated sewage. EcoSan, therefore, provides an attractive solution to both the sanitation, and agricultural production, crises in SSA.
Furthermore, the EcoSan framework mitigates the third interaction highlighted by Naafs: ‘sources of greenhouse gas’, as it's estimated EcoSan technologies emit up to 92% less greenhouse gases, than traditional waste management systems. Furthermore, HEDFs are more ecologically sustainable than chemical fertilisers, which are potent sources of nitrogen pollution. Therefore, EcoSan can provide a means towards sustainable development, and contribute to the mitigation of CC.
Whilst, the positive effects of EcoSan are clear, generally, studies show evidence of limited acceptance across SSA, due to faecophobic local, cultural perceptions associated with the process of using HEDFs for food production (Andersson & Minoia, 2017). Moreover, if we look back to my post on Cape Town, we can see how politically-driven desires for flushing toilets could also pose a barrier. Ultimately, cultural resistance poses the greatest barrier to the success of EcoSan systems, as users are the decisive determinants of the extent of change the EcoSan paradigm can effect.
However, the fact that EcoSan has been successfully adopted in various areas proves that the positive associations between sanitation, agricultural production and income generation, can ‘promote quite significant changes in attitudes toward (and practices surrounding) human excreta’ (Jewitt, 2011). And some prospects for encouraging the use of HEDFs include;
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| Figure 3. Whitened, dried pellets created by the LaDePa. Source: downtoearth.org |
- The use of ‘LaDePa’ machines to produce HEDF in the form of whitened, dried pellets, shown in figure 3. This was found to promote social acceptance in Durban’s eThekwini municipality.
- Chemical fertiliser subsidy programmes, currently available across SSA could be piloted for HEDFs, to encourage use.
Clearly, if implemented within an efficient logistics systems, and in a context of cultural acceptance, the EcoSan effectively adapts to, and mitigates CC. However, it should not be considered as a ‘silver bullet’ to sanitation issues, notably, gendered issues, which I will be exploring in my next post.
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