The Effects of MCRT and Temperature on Enhanced Biological Phosphorus Removal

Abstract

Temperature and low mean cell residence time (MCRT) effects on enhanced biological phosphorus removal (EBPR) were investigated in continuous flow bench-scale activated sludge systems treating settled domestic wastewater supplemented with 50 mg/l acetate over ranges of MCRT and temperature of 2-4 days and 13.5-20° C respectively. Temperature effects (10-37°C) on anaerobic soluble COD (CODsol) uptake and soluble P release (Psol) and aerobic Psol uptake rates were studied in batch. For the temperature range studied, EBPR functioned efficiently at MCRT ≥ 2.9 day; below 2.9 day MCRT EBPR is lost at an MCRT value that depends on temperature. Temperature effects on MCRT for EBPR (13.5-20°C), anaerobic CODsol uptake and Psol release rates and aerobic Psol uptake rates (10-30°C) are described by similar Arrhenius plots indicating a similar temperature dependency for all biological processes involved in EBPR.