NUTRIENT REMOVAL USING THE SIMPLE DUAL SLUDGE SYSTEM WITH AN UMBR (UPFLOW MULTI-LAYER BIOREACTOR) AND AEROBIC BIOFILM REACTOR FOR SMALL SEWAGE TREATMENT

In this study, a simple process using dual sludge was developed for the small and decentralized sewage treatment. It is a hybrid system that consists of upflow multilayer bioreactor (UMBR) as anaerobic and anoxic reactor with suspended growth microorganisms and post aerobic biofilm reactor with inclined plates. The HRT in the UMBR and the aerobic biofilm reactor were about 5.8 h and 6.4 h, respectively. The temperature in the reactor during this study varied from 12.5°C to 28.3°C The results obtained from this study show that effluent concentrations of TCOD, TBOD, SS, TN, and TP were 29.7 mg/L, 6.0 mg/L, 10.3 mg/L, 12.0 mg/L, and 1.8 mg/L, which corresponded to a removal efficiency of 92.7%, 96.4%, 96.4%, 74.9%, and 76.5%, respectively. The sludge biomass index (SBI) of the excess sludge in the UMBR was about 0.55, which means that the sludge in the UMBR was sufficiently stabilized and may not requires further treatment prior to disposal.