Proliferation of biomass and its impact on the operation of a submerged membrane bioreactor

Abstract

The aim of this work was to investigate the biomass proliferation and its impact on the operation of a submerged membrane bioreactor (sMBR). A programmable logic controller (PLC) was used to control the process of the sMBR with no discharge of sludge. When MLSS was 9670 mg/L and the solid retention times (SRT) ranged from 20 to 40 days, the optimal removal efficiencies of COD, NH3-N, TP were 93.89%, 93.02%, 80.57%, respectively. Accompanying with the decreasing of the sludge loading, the substrate and nutrition were insufficient in the sMBR, leading to endogenous respiration of the activated sludge, which decreased the activity of sludge and resulted in the death of more microorganisms.