Study On MABR Treatment Of Simulated Oilfield Wastewater

Oilfiled wastewater is a typically refractory wastewater, with characteristics of high concentration of COD, BOD, large toxicity and poor biodegradability. Membrane-aerated biofilm reactor(MABR) is a new type of sewage treatment technology which combines the gas sepration membrane technology with biofilm wastewater treatment technology, so MABR is feasible for refractory wastewater treatment inheriting the advantages of both membrane and biofilm technologies.In this paper, ADB350M, including efficient complex strains which was used for petroleum hydrocabons degradation was combined with MABR for simulated oilfiled wastewater treatment. A type of flow through polyolefin hollow fiber curtain membrane module of industrial application scale had been designed; The cultivation of ADB350M complex strains, biofilm growth on membrane and biofilm acclimation was explored; The feasbility of MABR treatment of simulated oilfiled wastewater was studied,ang the results showed MABR was feasbile for oil degradation with removal rate during 72～87%; The process and mechanisms of MABR in the degradation of oil compounds and nitrogen removal were studied; The effect of operating conditions on oil degradation process and its efficiency of MABR system was systematically investigated, and the optimum operating conditions were aeration pressure at 0.28MPa, mass ratio of surfactant and oil 1:10, pH 8.3, cycle velocity 18L/min, HRT 24h, temperature between 27～30℃; The performance of MABR system under different poor conditions was investigated, and the results showed MABR system was severely affected when under the conditions of low temperature, high surfactant content, cycle and aeration ceased, but MABR showed good adaptability when over acid and alkali, high and low load happened; The threshold of MABR system treatment of simulation oilfield wastewater.was studied, usually during 12～14%; The removal rate of saturated chain hydrocarbons, unsaturated chain hydrocarbons, aromatic hydrocarbon in MABR system was during 80～90%, 70～90%, 70～98% respectively, which showed good removal rate on various types of organic matter in wastewater. The GC/MS analysis revealed the main refractory organics were halogenated hydrocarbon, long-chain alkanes, polycyclic aromatic hydrocarbons and branched-chain hydrocarbons. The long term experimental results showed that the removal rate of oil content and COD was stable, during 75～90% and 70～86% respectively. In effluent, the NH_4-⁺N concentration was generally less than 2mg/L, NO-3-N during 1～3mg/L, NO-2-N less than 0.1mg/L, turbidity less than 50NTU, which showed the effluent was of high quality. MABR could realize stable remove of COD, oil content in simulated oilfield wastewater, so MABR had good application prospects in the treatment of oilfield wastewater.