Physico-chemical characteristics of fish ponds fed with septage

Abstract

Pilot-scale experiments were conducted under ambient, tropical conditions to investigate the physico-chemical characteristics of fish pond water fed with septic-tank sludge (septage). Four concrete ponds were loaded daily with septage at 75, 150, 300 and 450 kg COD/ha-d, and tilapia (a herbivorous fish) were stocked at 5 fish/m² in each pond. The septage loadings between 75 and 150 kg COD/ha-d resulted in pond water characteristics suitable for tilapia growth, and the maximum extrapolated yield of 7530 kg/ha-y was obtained in the 150 kg COD/ha-d loaded pond. The phenomena of septage sedimentation and solubilization to the pond water are discussed.