title: Two-stage SBR for treatment of oil refinery wastewater.
abstract: A two-stage sequencing batch reactor (SBR) system was used for treatment of oily wastewater with COD and oil and grease (O&G) concentrations ranging from 1,722-7,826 mg/L and 5,365-13,350 mg/L, respectively. A suitable start-up protocol was developed using gradual increase in oily wastewater composition with methanol as the co-substrate. This strategy enabled a short acclimation period of 12 days for the sludge in the two-stage SBR to adapt to the oily wastewater. After acclimation, the 1st stage and 2nd stage SBRs were able to achieve COD removals of 47.0+/-2.4% and 95.3+/-0.5%, respectively. The 1st stage SBR was able to achieve 99.8+/-0.1% of O&G removal and effluent O&G from the 1st stage SBR was only 6+/-2 mg/L. The 2nd stage SBR was used to further remove COD in the effluent from the 1st stage SBR. The final effluent from the 2nd stage SBR had a COD concentration of 97+/-16 mg/L with no detectable O&G content. Thus, a two-stage SBR system was shown to be feasible for treating high strength oily wastewater to meet the local discharge standards.
authors.affiliation: Centre for Water Research, Environmental Science and Engineering Programme, National University of Singapore, Singapore 117576.
authors.forename: L Y
authors.initials: LY
authors.lastname: Lee
authors.forename: J Y
authors.initials: JY
authors.lastname: Hu
authors.forename: S L
authors.initials: SL
authors.lastname: Ong
authors.forename: W J
authors.initials: WJ
authors.lastname: Ng
authors.forename: J H
authors.initials: JH
authors.lastname: Ren
authors.forename: S H
authors.initials: SH
authors.lastname: Wong
mesh_terms: D019149:Bioreactors; D007220:Industrial Waste / Q000517:prevention & control*; D000432:Methanol / Q000737:chemistry; D010100:Oxygen / Q000302:isolation & purification / Q000378:metabolism; D010578:Petroleum; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D012989:Soil Pollutants / Q000378:metabolism; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D007220:Industrial Waste; D010578:Petroleum; D012722:Sewage; D012989:Soil Pollutants; D010100:Oxygen; D000432:Methanol