Bio-fouling reducers for improving the performance of an aerobic submerged membrane bioreactor treating palm oil mill effluent

A bench scale aerobic submerged membrane bioreactor (ASMBR) was used to treat diluted palm oil mill effluent (POME). For further improving the effluent quality and reduction of bio-fouling, powdered activated carbon (PAC) and zeolite were used as bio-fouling reducers (BFR). We compared the performances of ASMBR without BFR (called BFR0) with ASMBR using BFR, namely 2 g/L PAC (BFR1), 4 g/L PAC (BFR2) and 2 g/L zeolite (BFR3) for a period of about 70 days. Each system with BFR showed distinct performances by producing higher effluent quality as compared with BFR0. On average, the systems with and without BFR removed COD by 97.5–98.5% and 95.2%, respectively. The ASMBR with BFR also produced permeate with average residual color between 16 and 26 Pt-Co, as compared to 80 Pt-Co by BFR0. The addition of BFR increased the critical flux from 20 LMH (BFR0) to 36, 42 and 30 LMH (BFR1, BFR2, and BFR3). Furthermore, the ASMBR systems with BFR formed lower operational trans-membrane pressure (TMP), lowered the concentration of soluble microbial products (SMP) and increased the concentration of EPS.

► PAC and zeolite were added as bio-fouling reducer (BFR).
► The addition of BFR in ASMBR increases effluent qualities.
► The addition of BFR in ASMBR decreases bio-fouling propensity.
► PAC shows better performance than zeolite in the enhancement of ASMBR system.