Pilot-scale experimental study demonstrates multi-stage ecological treatment of domestic septage, highlighting high contaminant removal despite remaining disinfection needs.
Key Points
To characterize domestic faecal sludge and septage and evaluate the performance of an eco-friendly, pilot-scale treatment plant designed to mitigate water pollution from human waste.
Constructed a 60 L/day pilot plant in Sonarpur, Kolkata, India, comprising a bar screen chamber, anaerobic pond, sludge drying beds, aerobic pond, constructed wetland, polishing pond, and stand-alone filter in series.
Conducted nine complete treatment cycles across four climatic seasons between September 2024 and August 2025.
Assessed performance across individual units and the total system by measuring nine water quality parameters against CPCB and EPA discharge standards.
The combined anaerobic pond and sludge drying beds achieved average removal efficiencies of 94.53% for TSS, 89.14% for COD, 89.48% for BOD3, 72.88% for total phosphorus, 53.61% for total nitrogen, 96.10% for faecal coliform, and 92.62% for total coliform.
The entire plant achieved cumulative average removal efficiencies of 98.44% for TSS, 94.78% for COD, 96.00% for BOD3, 95.12% for total phosphorus, 83.44% for total nitrogen, 99.69% for faecal coliform, and 98.84% for total coliform.
Treated effluent satisfied regulatory standards for pH, TSS, COD, and faecal coliform, though additional treatment and disinfection remain necessary to meet standards for BOD3, total phosphorus, total nitrogen, and total coliform.