Design and Performance Evaluation of DEWATS for Sustainable Fecal Sludge Treatment

Abstract

Fecal Sludge Management (FSM) is a critical aspect of sanitation in developing countries like Pakistan, where on-site sanitation systems are prevalent due to limited sewer networks. This study investigated the effectiveness of a Densified Effluent Treatment System (DEWATS) for treating fecal sludge. The DEWATS unit comprised an Anaerobic Baffled Reactor (ABR) followed by Anaerobic Filters (AF). The DEWATS unit was constructed with six chambers, with the first two functioning as ABR and the remaining four as AF. Synthetic fecal sludge was prepared to mimic real fecal sludge characteristics. Real fecal sludge samples were also collected from various sources. The study found that the DEWATS process was successful in removing organic matter and solids from both synthetic and real fecal sludge. Treatment efficiencies were high for COD (73%), BOD (74%), TSS (71%), and VSS (65.5%). However, lower to moderate removal efficiencies were observed for TKN and TP. The composition of fecal sludge also influenced treatment performance, with a mixed sample (household and commercial) achieving the highest removal efficiency. In conclusion, DEWATS appears as a promising technology for fecal sludge treatment in Pakistan. Further research is needed to optimize nitrogen and phosphorus removal and account for variations in real-world fecal sludge characteristics.