Let’s talk shit – multiple returns from sanitation solutions targeting resource recovery in South Africa

The Sustainable Development Goals (SDGs), adopted by all United Nations Member states in 2015, took a stand compared to the previous goals, not just aiming for increased sanitation coverage but for 2030 to ‘ensure availability and sustainable management of water and sanitation for all’ (SDG 6). Sanitation is vital for health and dignity, particularly for menstruating girls’ school attendance. Toilets provide sanitary conditions for the user, whereas the safe management of excreta aims to prevent ”downstream” contamination and disease transmission. Despite progress, 3.5 billion (43% of the global population) lacks safely managed sanitation services.  A role of sanitation stressed in SDG 6, but often neglected, is providing nutrients to agriculture. Since the nutrients in the consumed food end up in the excreta in a constant flow, sustainable nutrient management of food production needs to consider this untapped resource.

In South Africa, a large proportion of the population (81%) uses improved (i.e. for the user judged safe) sanitation facilities. 57% of these are solutions based on flushing and connected to a sewer system, whereas 34% have on-site sanitation solutions such as ventilated pit latrines and traditional, non-ventilated pit latrines. Being a water-scarce country, the South African 2016 National Sanitation policy emphasizes the importance of responsible use of water resources both in terms of water use and protection of the water environment. For this reason, on-site sanitation is recognised as an acceptable long-term and decent sanitation service that may help fill the sanitation gap for the more than 5 million South Africans who do not have safe sanitation solutions.

Faecal sludge management in South Africa

Increasing the sanitation coverage with on-site solutions is, however, challenged by on-site management and faecal sludge management services being limited and severely challenged, and poor servicing of on-site sanitation options has led to facilities perceived as unhygienic. In contrast to water-born sanitation systems, the on-site sanitation management chain has many broken links with unclear responsabilities and mandates. To overcome these challenges, a National Fecal sludge management (FSM) strategy was released in 2023. The 10-year FSM strategy for South Africa aims for clear regulatory and financing frameworks across the service chain; the development of a variety of appropriate and affordable on-site sanitation technologies; increased capacity along the service chain and the ingration of private sector service providers.

Fertiliser potential in excreta and soil health

Agriculture in South Africa is challenged by water scarcity, drought, land degradation and soil erosion. To maintain agricultural yield, it is vital to replace nutrients removed with the harvest so that the soil is not mined on its nutrients. However, soil degradation is a vicious problem since the response to plant nutrients is limited for degraded soils, especially with mineral fertilisers supplying most often only a few macronutrients and no organic matter. Compounds that conventional waterborne sanitation sees as problems/pollutants (i.e. the nutrients and organic material) can serve as valuable input to agriculture, and the 2016 South African National Sanitation Policy encourages the reuse of the products of sanitation services. Apart from containing all the nutrients we have consumed, from macronutrients such as nitrogen, phosphorus and potassium to trace elements, the excreta also contains recalcitrant organic carbon that can improve water holding capacity and and provide soil nutrient supply over several seasons. Nitrogen has been estimated as the main constraint for South African smallholder maize production. By applying human urine at a rate of 4 kg N/ha, in addition to ordinary practice, maize yield could increase with an average of 12 % across South Africa (Andersson et al. 2013).

Safely managed excreta and the role of container based sanitation

The core objective for sanitation is the protection of human health, mainly based on keeping excreta away from people, which is not necessarily sound/sane management from environmental and resource perspectives. This means that long marine outfalls, using the ocean as a dumping ground, are by Unicef/WHO counted as safely managed sanitation solutions. Faecal sludge generated on-site is usually dealt with infrequently or not at all, and locations or configurations of pit latrines can make manual emptying the only option. Neither the waterborne sanitation nor many of the pits have been designed from a resource perspective but as a disposal strategy.

There is a dire need for on-sanitation systems capable of meeting stringent discharge or reuse criteria, simple to operate and maintain, reliable, and resilient to unreliable electrical service.  Sanitation systems designed for resource recovery, such as non-sewered and container-based sanitation (CBS) systems, can optimise recovery. These systems can operate without connection to any sewer network or drainage system and do not depend on water to transport waste.  They also offer additional benefits such as being less dependent on infrastructure and thus more resilient. Resource recovery is an incentive for pathogen inactivation and a safe management of excreta, where various treatments, including ammonia sanitisation, can be used to achieve this.