عنوان مقاله [English]
The objective of this study was to evaluate the feasibility of treating refinery wastewater to meet the applicable discharge limits and agriculture use standard consistently using membrane bioreactor (MBR) technology to reduce either the environmental impacts of refinery waste water discharge or operational problems of common activated sludge process (ASP). A pilot scale submerged membrane bioreactor with a membrane module that consists of 56 flat sheet poly (ether sulfone) (PES) ultra filter membranes was used in this study. The effluent of the dissolved air floatation (DAF) unit from wastewater treatment plant of Tehran refinery was used as a feed. Trials on different membrane fluxes and hydraulic retention time (HRT) were conducted. The results have shown that the hydraulic retention time of 15.87 (hr) was more applicable. The percentage removal of COD, BOD5, TOC, Oil and grease, TSS, and color was 97.32, 92.58, 96.36, 99.18, 99.99, and 95.58 respectively. The results showed that the quality of the product consistently met the requirement for agriculture use and discharge to the surface water. Due to an increase in mixed liquor suspended solids concentration from 6000 mg/l to 9900 mg/l at the end of experiments, the removal rate was increased from 86.00% at the first stage to 97.32% and 95.22% at the second and third stage respectively. It was concluded that it was feasible to treat the wastewater using SMBR technology.