Application of halophilic microorganisms in osmotic membrane bioreactor (OMBR) for reduction of volume and organic load of produced water

Abstract

The purpose of this study was to use halophilic microorganisms and forward osmosis (FO) membrane to reduce volume and organic pollutants from synthetic saline produced water (PW) in an osmotic membrane bioreactor (OMBR). The enriched bacterial community was initially cultivated in synthetic PW using a sequential batch bioreactor. A suitable mixed liquor suspended solids (MLSS) was prepared with organic loading rates of 0.16–1.2 (kg COD m–3d–1). The MLSS concentration increased to 1000 mg L–1, and a reduction in chemical oxygen demand (COD) greater than 90 % was obtained after 65 days. The OMBR was then inoculated with the acclimated halophilic microorganisms for an influent of 1500 mg L–1 COD and 10,000 mg L–1 total dissolved solids (TDS). The results showed more than a 98 % COD reduction in the permeated water to the draw solution, resulting from a high rejection of the FO membrane. The FO membrane reduced the PW volume by almost 30 % and the operation of OMBR decreased two-thirds and 88 % of the influent COD and oil and grease, respectively due to the suitable biological degradation. These findings demonstrate the potential use of OMBR for pretreatment of PW.