Aiming to work on the development of concrete projects regarding access to drinking water and sanitation, “Initiative Dakar 2021” was launched on the 16th of January 2020 in Diamniadio, a city close to Dakar. The results will be presented at the 9th World Water Forum in 2021 and “serve as a catalyst for the achievement” (Sène, 2020) of the SDG 6.2. This operation emphasises the challenges that remain due to the lack of safe and sustainable sanitation, including in Senegal and its capital.
According to the WHO, 2.5 billion people (a third of the world’s population) still lack access to improved sanitation (CDC, 2016) with 673 million who practice open defecation, while 1.8 billion drink faecally contaminated water.
In Sub-Saharan Africa, sanitation access in urban areas is mostly provided through onsite sanitation technologie which result in faecal sludge (FS) accumulation when no proper management system is in place. In Dakar, “39% [of households] have on-site or semi-collective systems and only 25% are connected to the sewer network” (Scott, 2013). The most common onsite systems are typically pit latrines and septic tanks which often lead to unsustainable and inadequate services. Half the pits are emptied manually in Dakar, while waste is often dumped in the environment impacting on health of the vulnerable poor.
Sewerage systems, in which FS is piped away for disposal elsewhere, are often viewed as too costly at both financial and environmental levels and too difficult to maintain in African contexts.
Like most African cities, Dakar hence lacks sewerage networks which are often “dysfunctional” or “serve only wealthy” districts (Norman, 2011).
The UN, World Bank and WHO considered sewerage and onsite technologies to be “equivalent improved sanitation systems” (Dodane, 2012), meeting the MDGs for sanitation. However, the management of FS from onsite technologies were not included in their definitions, leading to projects that often did not address FS-related issues.
The management of FS from onsite sanitation systems therefore appears as a priority in cities like Dakar, especially in poor areas. FS needs be collected, treated and disposed of through the “sanitation service chain” (Medland, 2016), collectively know as Faecal Sludge Management (FSM).
FSM system is much more relevant than sewerage systems in places like Dakar. It is more robust because not reliant on electricity which is highly valuable in Dakar where power blackouts frequently occur. It is also more adaptable to the dense and growing urban infrastructure, while the failure of one component has little impact on the overall system.
Funded by the World Bank and designed by the ONAS, the PAQPUD project was “the first large-scale implementation of low-cost sewerage in sub-Saharan Africa” (Norman, 2011) that ran from 2001 to 2009. Focused on low-income areas of Dakar, the project installed settled sewerage systems which basically involve “the sewering of septic tanks, such that solids settle and remain on-site, and only the liquid fraction is piped away” (Norman, 2011). Despite improvements, this ‘pro-poor’ project yet excluded many of the poorest households, while others were not able to participate because they could not afford the fee, had no toilet or did not even know about the project.
One ONAS’ success so far is “the implementation of a call centre for faecal waste trucks” (IWA) that enables competition among the truck companies, reduces the service price and increases the efficiency of waste collection.
Nonetheless, sanitation still places a high economic burden on households due to the lack of financially viable management of the sanitation service chain. One way to generate additional cash flow is at the back-end of the chain through waste recovery that could reduce the amount paid by households and increase their ability to cover for service which in turn improves the overall access to sanitation.
In Dakar, 15% of the wastewater is treated, while the rest is discharged untreated into the ocean. Only 1500 m3 of faecal sludge is collected daily and delivered to the treatment plants, while the remaining 4500 m3 is disposed of directly into the environment (Diener, 2014) and thus lost, whereas it could be a valuable resource (fuel for combustion, biogas, protein for animals, building material, soil conditioner, organic fertiliser). The only faecal recycling observed in Dakar “is very limited agricultural use of sludge as a soil conditioner and fertilizer” (Diener, 2014).
Designed to be flexible and self-sustaining, the Janicki Omni Processor aims to produce electricity, safe water and ash (used as fertiliser or building material) from faecal sludge (Gates, 2015).
Funded by the Gates Foundation, the pilot project (Cashman, 2020) in Dakar was set up in 2015 and has taught several lessons for the larger commercial version that is currently being planned. However, this technology has a high initial cost and hence rely on the big banks and investors’ interest.