The effectiveness of proper hygiene practices in managing the spread of the Covid-19 virus has highlighted the critical importance of appropriate sanitation and good hygiene practise in managing disease transmission.
Considering the role that a simple behaviour, such as the washing of hands, has played in separating many people from the virus, there has been a notable interest in and greater motivation to pay greater attention to WASH projects. This is evidenced by, for example, the focus by governments on ensuring that there are adequate hand-washing facilities at schools to help contain the spread of the virus and by the consistent handwashing messaging in the media.
“Governments and policymakers have realised that improving WASH, including safe water, adequate sanitation and hygiene education, has a profound positive impact on public health. As far back as 2011, a World Health Organisation study, Water, sanitation and hygiene interventions and the prevention of diarrhoea, notes that water supply interventions can reduce incidence of diarrhoea, for example, by 5%, water quality interventions by 19% (after 12 months), sanitation interventions by 36% and handwashing interventions, alone, by a staggering 47% for hand washing with soap,” Robyn Tompkins, an Executive Associate of JG Afrika and the firm’s WASH Specialist, says.
Tompkins continues to lead many WASH projects on behalf of JG Afrika, a leading firm of engineers and environmental scientists. Geared at changing behaviours to ensure the greatest sustainable impact, these projects rely on a multi-skilled team of professionals and are long-term in nature.
The focus of these projects includes preventing human contact with pathogens. This, according to a definition of WASH in CSE India’s Introducing City Sanitation Plan: Practitioner’s Manual, is fundamental to the safe management of human excreta including its safe confinement, collection, treatment, disposal and associated hygiene-related practices.
According to the United Nations Joint Monitoring Program report of 2019, Progress on household drinking water, sanitation and hygiene I 2000-2017, only 40% of the global population have access to safely managed sanitation facilities and 3-billion people do not have adequate handwashing facilities at home. Even last year, almost 10% of the world’s population practised open defecation, while, according to Organisation for Economic Co-operation and Development’s report in 2019, Access to Water and Sanitation in Sub-Saharan Africa, 72% of people living in sub-Saharan Africa do not have access to sanitation.
There is a high reliance on on-site sanitation technologies, such as septic tanks or pit latrines. This is especially the case in peri-urban and rural areas of southern Africa where it may not always be feasible, or there is insufficient technical capacity or financing available to implement and operate waterborne sewage systems.
The safe management of faecal sludge, comprising human excreta, water, and solid waste, across the sanitation service chain from the user interface (basically the toilet) to the point of end-use or disposal is therefore of critical importance in national planning.
There is a real risk that humans will be exposed to human excreta at any point in the process. At origin, for example, the handling of faecal sludge varies from one system to the next, while its transportation to treatment plants may involve different organisations and methods of collection and conveyance.
In some instances, treatment plants do not have sufficient capacity to adequately process the faecal sludge before releasing it into the environment. Often, treatment plants are designed for wastewater processing rather than faecal sludge processing, and management systems are set up for sewage rather than faecal sludge. People are at risk across the sanitation service chain, from exposure to excreta or the pathogens associated with it.
However, new sanitation technologies, which can be implemented quicker and more cost-effectively than large, centralised sanitation systems, are becoming increasingly available to developing economies to help overcome these challenges. They have, therefore, become a significant focus point for WASH professionals, such as Tompkins.
For example, innovative apps now allow community members to locate and book the services of the nearest private drainage operators to drive up the uptake of these services among low-income residents, as has been the case in Dakar, Senegal.
Collection services were previously unaffordable for many residents of the city and they would, therefore, rather manually remove the waste themselves or pay someone to do this on their behalf, with the contents often illegally emptied in the open environment.
Working on the same premise as Uber, residents use text messages to order the services of private drainage operators who have registered on the system and compete on auction to claim a desludging request.
Based on Global Positioning Satellite technology, the system has also enabled the Senegalese government to collect valuable information to improve evaluation and monitoring for sanitation planning.
“For example, they now know how often the septic tanks are being emptied; how many trips are being undertaken by the operators; and exactly where the faecal sludge is being disposed. This information has also facilitated the regulation of the many operators, while the platform has provided an entry point for more private sector participants in the desludging industry, creating employment opportunities and further potential to drive down the costs of drainage,” Tompkins says. In addition, the city government in Dakar have created an enabling environment for private operators to manage and operate these decentralised wastewater treatment systems – or DEWATs, improving both livelihoods opportunities for citizens and self-regulation of the faecal sludge service delivery chain.
In India, among the world leaders in new sanitation technologies, decentralised sanitation systems are having a profound positive impact on the living conditions of low-income communities.
A case in point is a system that is treating about 50KLD of the total wastewater from Kuchhpura slum in Agra, India. This cost-effective solution that is also simple to maintain has reduced biological-oxygen demand by 61%, chemical-oxygen demand by 64% and total-dissolved solids by 94%, and there is immense potential to also adapt it for areas in Africa.
An article published on the Centre for Science and Environment’s (CSE), a public interest research and advocacy organisation based in New Delhi, website (https://www.cseindia.org/ ) explains the process as follows:
The wastewater is received from five clusters via a common drain. Separated from solid waste via a screen chamber, wastewater enters three chambered septic tanks where it undergoes primary treatment. Secondary treatment is undertaken in nine chambered baffled anaerobic reactors which are filled with gravels. The wastewater is then sent to a filter bed that is filled with white river pebbles, red stones, and gravels, and planted with Canna indica for root zone treatment. Notably, the treated wastewater is used by the community for horticulture and irrigation and, in so doing, also creating many open green spaces in this area.
However, this new thinking around sanitation goes further by also focusing on producing many end products from faecal sludge as part of the circular economy.
Tompkins says that studies undertaken in Dakar, Senegal; Accra, Ghana; and Kampala, Uganda; have demonstrated that there are five groups of end products that can be derived from processing faecal sludge, as well as there being a viable market for them that varies from one city to the next. These products include dry sludge as fuel for combustion; biogas from anaerobic digestion of sludge; protein derived from sludge processing for use as animal feed; dried sludge as a component in building materials; and treated sludge as a soil conditioner or organic fertilizer.
In South Africa, faecal sludge from VIP toilets is being extruded to produce pallets using Latrine Dehydration Pasteurization, or “LaDePa”, technology that was developed by eThekwini Water and Sanitation and Particle System Separation.
According to Septein et al in their 2018 paper on the LaDePa process, the pellets are dried using infrared radiation to destroy pathogens, including E. Coli, Salmonella, Shigella and Vibrio Cholerae. Notably, this unique method of drying faecal sludge also reduces the mass and volume of the material and, in so doing, lowering the costs associated with its transportation, handling and storage.
As part of a pilot phase, these dried and pasteurized pellets will be sold as an agricultural product. According to Septein et al, “this can be considered one of the most natural routes of reuse as the use of human excreta in agriculture closes the loop of the nutrient cycle”, while the dried faecal sludge can also be used as a biofuel in line with the circular economy.
At the same time, an innovative means of treating faecal sludge was recently commissioned in Durban. It involves harvesting Black Soldier Fly larvae, which eat human faecal waste to reduce its volume, after composting with a combination of food and faecal origin for further processing into a branded nutrient product for the agricultural market.
Based upon Agriprotein’s Black Soldier Fly larvae technology, the system was developed by Khanyisa Projects via a grant from the Bill & Melinda Gates Foundation.
Notably, this new thinking around sanitation has also created immense opportunity for increased private sector participation, not to mention local livelihoods.
As the nucleus of the new circular economy, experts, such as Dhesigen Naidoo, Chief Executive Officer of the Water Research Commission, believe that sanitation could possibly produce the world’s next ‘Unicorn’, a privately held start-up company with a market of over US$ 1-billion. This revenue would be generated from the removal of microconstituents; the engineering of microbial pathways and technologies; water quality and reuse; biorefining for chemical recovery; energy recovery; and greenhouse gas management for the cities of the future.
Another sound example of the extent of ongoing innovation by companies in the field of new sanitation technology is a community-scale faecal sludge-treatment unit that is being developed by a partnership between Tide Technocrats, Biomass Controls and the Bill & Melinda Gates Foundation.
According to Biomass Controls’ website (https://biomasscontrols.com/), the company manufactures a biorefinery that cleanly processes high moisture biogenic resources to produce thermal and electrical energy, water and biochar, while also generating revenue from tipping fees and service contracts. It recently included human faecal sludge as a resource to produce thermal energy and biochar (a charcoal-like fuel product).
The technology is integrated into a transportable shipping container and can be established on site in a few days to service communities of between 10 000 and 50 000 people.
Notably, these are also among some of the technologies that Tompkins and her team will be assessing for their suitability for end-use processing in a faecal sludge management pilot project in Polokwane, Limpopo. It is being undertaken in collaboration with the South African Department of Water & Sanitation as part of the United States Agency for International Development Resilient Waters Program.
The project is an extensive undertaking that entails using tools, such as a Faecal Flow Diagram (SFD) and a City Service Delivery Assessment, as well as the World Health Organisation’s Sanitation Safety Plan.
“This project will entail creating a platform, through improving sanitation management, to develop a broader urban resilience toolkit in the context of the circular economy in Polokwane. We will use the evidence generated by this and other projects to develop a Faecal Sludge Management Strategy for South Africa. There is a growing realisation that we cannot use resources as we have done in the past. The problem cannot just be flushed away. We need new and innovative thinking to deal with a growing challenge, especially in southern Africa where we are caught between inadequate sanitation facilities and a high risk of climate change, which will impact the resources we do have,” Tompkins concludes.
 Septein S, Singh A, Mirara SW, Teba L, Velkushanova K, Buckley CA. 2018. ‘LaDePa’ process for the drying and pasteurization of faecal sludge from VIP latrines using infrared radiation [Online]. South African Journal of Chemical Engineering. Volume 25, June 2018, Pages 147-158. Available at: https://www.sciencedirect.com/science/article/pii/S1026918517300938