| Project Detail |
Globally, it is estimated that three billion people are served by onsite sanitation, and in low-income countries entire urban areas are not served by sewers. Methods for the safe management of faecal sludge from onsite sanitation are desperately needed, as it is mostly discharged untreated in the urban environment, placing a huge burden on public and environmental health. Onsite sanitation is only recently acknowledged as a viable long-term solution, and knowledge cannot be directly transferred from municipal wastewater treatment due to different characteristics, variability, and fundamental properties. Consequently, research lags substantially behind knowledge of wastewater treatment processes, and as awareness of the need for faecal sludge management is increasing, people are implementing untested treatment solutions in situations where we cannot risk failure.From a technical perspective, the greatest obstacle to overcome in developing safely managed solutions are an understanding of faecal sludge that accumulates with microbial degradation and stabilization during storage in containment, in order to develop reliable and safe management of faecal sludge arriving at treatment. In situ knowledge of biological processes occurring within onsite containment of faecal sludge is scarce. The current conceptual model that time is a predictor of characteristics of faecal sludge during storage in containment does not hold up to scientific investigation. The objective of this research is to understand underlying mechanisms and interactions of biological processes occurring during storage of faecal sludge in onsite containments, in order to develop necessary scientific knowledge for the implementation of robust, reliable, and low-footprint solutions for dense urban areas. This research specifically addresses the following questions:•What role do different spatial zones of microbial activity play in the stabilization processes occurring during storage within onsite containment? We expect that faecal sludge in containment is not mixed and has very heterogeneous regions of microbial activity. This will be evaluated through in situ sampling of faecal sludge in containment to investigate redox conditions, organic fractions and microbial communities, followed by replication in laboratory reactors.•How do properties of faecal sludge that arrives at treatment plants control dewatering performance and downstream biological treatment? We expect that dewatering performance will vary based on dewatering technology, as will the resulting fractions of organic matter in supernatant. This will be evaluated with sampling of faecal sludge at treatment plants to investigate properties of aggregates, bulk solutions, dewatering, level of stabilization and resulting fractions in supernatant, followed by exploring treatment configurations with laboratory reactors. To address these questions, we will integrate the experience at Eawag in monitoring and implementing improved faecal sludge treatment technologies in low-income countries, together with existing expertise in wastewater treatment, reactor design, microbiological community analysis, and sampling methods. For uptake, we will link and field-test results with our ongoing research in Zambia, and Uganda. As faecal sludge research is a relatively unexplored field, the knowledge gained of fundamental mechanisms has the possibility to have a significant and direct impact on improving global sanitation, and progress towards meeting Sustainable Development Goal (SDG) 6. |
