Dynamic membrane bioreactor performance for treatment of municipal wastewaters at different sludge concentrations

In this study, the effect of sludge concentration on the performance of an aerobic dynamic membrane bioreactor (DMBR) was investigated. Low-cost polyester hollow fiber support material was used for the formation of dynamic membrane (DM). Treatment and filtration performances of the DMBR were investigated at two different sludge concentrations (5 g/L; 10 g/L). Both DMBRs were operated at a flux of 18 L/m² h The DM could be operated at steady conditions for 51 and 24 days at sludge concentrations of 5 and 10 g/L, respectively. High treatment performance and permeate quality were achieved at each sludge concentration. High chemical oxygen demand (COD) removal (>88%), low total suspended solids (TSS) concentrations (<10 mg/L), and low turbidity values (<1.15 NTU) were achieved by both DMs. However, a shift to a relatively larger range in particle size distribution of permeate were observed at high sludge concentration. Furthermore, higher transmembrane pressure was observed at the sludge concentration of 10 g/L, resulting in a rapid clogging. At the tested conditions, overall results indicated that selection of the optimum sludge concentration played a significant role in achieving homogeneous and stable DM layer in DMBRs.