An integrated assessment of fecal sludge management (FSM) in Islamabad, Pakistan: challenges and treatment solutions

Considering differences between sewered and onsite sanitation facilities, tools for holistic sanitation diagnostics are required to plan management solutions for city-wide inclusive sanitation. This study presents an integrated assessment of fecal sludge management with combined use of excreta flow diagrams and quantitative and qualitative analysis to evaluate fecal sludge volumes and composition accumulated in the onsite sanitation. The excreta flow diagram revealed that only 9% of the wastewater gets treated whereas 25% of the fecal sludge is buried underground while the remaining 66% are dumped directly into the environment openly without any treatment due to no designated disposal site. The study also highlights the variability in fecal sludge characteristics, with pit latrine sludge exhibiting 10–100 times higher concentrations of total solids, volatile solids, and chemical oxygen demand compared to septic tank sludge. The findings reveal that the indicators correlating fecal sludge characteristics are containment type, income level, and emptying. The presence of helminth eggs, particularly Ascaris Fertile Lumbricoids, within the sludge poses a risk to human health. In conclusion, this study highlights the immediate need for improved planning and implementation of fecal sludge management in low-middle income countries like Pakistan. The study's recommendations for treatment solutions aim to address the concentration and pathogen risks associated with fecal sludge, ultimately contributing to improved sanitation and public health outcomes.