Sanitation access in urban areas of low-income countries is provided through unstandardized onsite technologies containing accumulated faecal sludge. The demand for infrastructure to manage faecal sludge is increasing, however, no reliable method exists to estimate total accumulated quantities and qualities (Q&Q) This proposed approach averages out complexities to estimate conditions at a centralized to semi-centralized scale required for management and treatment technology solutions, as opposed to previous approaches evaluating what happens in individual containments. Empirical data, demographic data, and questionnaires were used in Kampala, Uganda to estimate total faecal sludge accumulation in the city, resulting in 270 L/cap∙year for pit latrines and 280 L/cap∙year for septic tanks. Septic tank sludge was more dilute than pit latrine sludge, however, public toilet was not a distinguishing factor. Non-household sources of sludge represent a significant fraction of the total and have different characteristics than household-level sludge. Income level, water connection, black water only, solid waste, number of users, containment volume, emptying frequency, and truck size were predictors of sludge quality. Empirical relationships such as a COD:TS of 1.09 ± 0.56 could be used for more resource efficient sampling campaigns. Based on this approach, spatially available demographic, technical and environmental (SPA-DET) data and statistical relationships between parameters could be used to predict Q&Q of faecal sludge.

Abstract:The majority of residents in low-and middle-income countries are served by onsite sanitation. Equitable access to sanitation, including emptying, collection, and transport services for the accumulation of faecal sludge remains a major challenge. Comprehensive information on service coverage by mechanical faecal sludge emptying service providers is lacking. The purpose of this study is to analyse the spatial distribution of service coverage and identify areas without faecal sludge emptying services in Kampala, Uganda. The study uses GIS (geographic information systems) as a tool to analyse real-time data of service providers based on GPS (global positioning system) units that were installed in a representative number of trucks. Of the total recorded 5653 emptying events, 27% were located outside Kampala city boundaries. Of those within Kampala city boundaries, 37% were classified as non-household customers. Areas without service provision accounted for 13% of the total area. Service provision normalised by population density revealed much greater service provision in medium-and high-income areas than low-and very low-income areas. The employed method provides a powerful tool to optimise faecal sludge management on a city-wide scale by increasing sustainability of the planning and decision-making process, increasing access to service provision and reducing faecal sludge transport times and costs.

The urban population will rise to 6.7 billion by 2050. The United Nations has committed to provide everyone with safely managed sanitation, but there is limited understanding of the scale of the challenge. This paper describes a methodology for rapid assessment of sanitation in cities including a graphical representation (a shit-flow diagram or SFD) and reports on findings from implementation in 39 cities. The SFD provides high level information for planning purposes covering the entire sanitation system in a city. More than half of the human excreta produced in these cities is not safely managed. The most significant portions of the unsafely managed excreta are: (i) contents of pits and tanks which are not emptied and are overflowing, leaking, or discharging to the surrounding environment (14%); (ii) contents of pits and tanks which are emptied but not delivered to treatment (18%); (iii) fecal sludge and supernatant delivered to treatment but not treated (3%); (iv) wastewater in sewers not delivered to treatment (14%); and (v) wastewater delivered to treatment but not treated (6%). Many cities currently relying on onsite sanitation for safe storage, particularly in Africa, will need new strategies as populations grow. Containment systems that discharge to open drains are common in some Asian cities; these pose a public health risk. Dumping of excreta is widespread and there is a lack of realistic performance data on which estimates of the extent and effectiveness of treatment can be made. The SFD production process can be challenging due to a lack of data and low technical capacity in cities. There is often uncertainty over terminology and over the status of infrastructure. Formalizing definitions for the SFD preparation process was found to be useful in overcoming capacity constraints in cities. The SFD produces a credible snapshot of the sanitation situation in a city. The paper provides evidence of the urgent need for improved management and monitoring of urban sanitation in cities around the world and highlights the role of the SFD as a planning tool.

Background: There is an unmet demand for community-scale fecal sludge treatment units (FSTUs) that serve communities of between 1,000 and 50,000 people and are able to operate in non-sewered and off-grid environments. An emerging industry standard for FSTUs includes as a key criteria energy independence in steady-state. Theoretically, there is sufficient thermal energy available in fecal sludge to provide the electrical power needed to run the FSTU. However, such a system had never been implemented. Methods: Biomass Controls has previously demonstrated the thermal treatment of fecal sludge using the Biogenic Refinery, a thermal FSTU deployed in three sites in India. In this article we describe testing where a Biogenic Refinery was paired with a thermal fluid heat exchanger and organic Rankine cycle generator to generate electrical power. Results: This Biogenic Refinery combined heat and power system generated sufficient electrical power to offset electrical parasitic loads in steady-state operation and produce a surplus of 1.2 kWe. Conclusions: The results of the study demonstrate that there is an excess of energy available and reliable mechanisms to generate electrical energy using an FSTU. Additional steps are necessary to transition to a true off-grid FSTU.

Safely managed sanitation services, monitored by the United Nations 2030 Agenda for Sustainable Development, require data on treatment of excreta from sanitation systems. This data is not readily available for the majority of United Nations member states and has led to estimates being established mostly for those countries where conventional sewer-based sanitation systems are prevalent. Presented in this article is a decentralized portable treatment unit for the safe treatment of excreta and sludges from non-sewered sanitation systems. Data from daily operations is generated from a variety of sensors, each collecting approximately ten data points per minute. Innovative cloudbased methods and data science tools are implemented to collect, store and analyze data. A software platform was developed that offers real-time reporting and alerts to operators and supervisors, allows for remote operation and control, and provides a multi tier architecture that enables user interaction through a mobile or web interface. Key Performance Indicators and results from long-term analytics are presented to quantify the effectiveness of the treatment process and provide relevant information to improve daily operations.Engineering