Use of a coupled SBR–MBR for treatment of produced water enriched by halophilic bacteria

The performance of a sequencing batch bioreactor (SBR) coupled with a membrane bioreactor (MBR) for treatment of hypersaline produced water by insertion of a halophilic bacterial consortium was tested at three different organic loading rates (OLRs): 1, 2 and 4 (kg chemical oxygen (O₂) demand (COD)/m³)/d. Four total dissolved solids (TDS) concentrations (20, 50, 80 and 120 g/l) were investigated in this study. At different TDS concentrations and OLRs, COD removal was found to be efficient at 91·3–99·5% and the amount of mixed liquor suspended solids (MLSS) varied from 4·61 to 9·88 g/l. The amounts of COD removal and MLSS increased with increased OLRs and decreased in hypersaline concentrations. Increases in TDS had a negative effect on membrane flux and fouling rates, but, in this hybrid system, the reduction in flux with increase in TDS was minor, while high-quality treated water was produced from the immersed membrane.