The Application Study Of Submerged Anaerobic Membrane Bioreactor Treating Dairy Wastewater

Recently anaerobic biological technology was largely applied in treatment of organic wastewater because its benefits of stable process,saving energy,and running simply.But conventional anaerobic reactor had the faults of low mass transfer rate,low microbe activity to treat wastewater.Therefore the high-efficient anaerobic reactors have to research.Anaerobic membrane bioreactor technology in the retention of low investment, low energy consumption, recyclable use of biogas energy, load a high capacity,sludge less,resistant to shock loading, and so on for anaerobic biological treatment technology.On the basis of a number of advantages, due to the efficient membrane modules retain the role of separation so that the biomass does not drain from the reactor to achieve an effective separation of SRT and HRT.This paper studied while the submerged anaerobic membrane bioreactor (SAMBR) application to treat the dairy wastewater,. Research the treatment effect and the reasons for membrane fouling while SAMBR in dealing with diary wastewater,and membrane cleaning of the reasons for the recovery effect on membrane flux. Therefore, to study the treatment effect and slow the membrane fouling by powdered activated carbon (PAC) addition. Through research, access to the following main conclusions and results:(1) SAMBR system showed good removal of organic matter and long-term operation stability, the removal of organic matter was common effects of biological degradation and membrane cut-off. After the stable operation of the reactor, HRT for the 2d, the concentration of COD_cr and BOD₅ of influent was no more than 2500mg/L and 1500mg/L, when, COD_cr and BOD₅ removal rate basically stable at more than 80.2% and 96.6% by SAMBR system, and in which microorganisms removal rate was 38.5% and 79.2%, and membrane retention efficiency stable at 35.2% and 9.1%.(2) The VFA concentrations were stable at no more than 292.1 mg/L and 43.8mg/L before and after membrane filtration, and both was increased with the influent COD_cr concentration increases; the pH was stabilized at 6.90～7.20 and 7.20～7.50 before and after membrane filtration, and both was decreased with the VFA concentration increases. And SAMBR was running without acidification.(3)The quality of effluent was almostly not affecte by membrane fouling,membrane fouling was mainly affect membrane flux.(4) The methane production of process of anaerobic biodegradation was relation with the part of the COD_cr which was removed,and there was a good linear relationship between them,the formula y = 0.3819x +0.031, the correlation coefficient was 0.99, about 96% of the removed part of the COD_cr have been converted to methane.(5) During the SAMBR running, the inorganic sediment was the main pollutants that caused membrane fouling at the early time, running late,colloid was the main pollutants that caused membrane fouling, dissolved organic matter on membrane fouling was not very significant.(6) The fouled membrane was cleaned by use 5% NaClO solution immersion 24h, and then 5% NaOH solution immersion 2h,this cleaning methods was available to a good cleaning effect, the membrane flux recovery rate was about 88%.(7) The COD_cr removal rate by SAMBR system was increased by PAC addition, but not increased with increased the PAC dosage, when PAC dosage was 1000mg/L, the COD_cr removal rate was the highest rate by SAMBR system.(8) PAC addited can effectively decrease the membrane filtration resistance, thus reducing membrane fouling,the main part of membrane resistance was the cake layer resistance and membrane fouling resistance without PAC addition,and the main part membrane resistance was instrinc membrane resistance after PAC addited,when the PAC dosage was 1000mg/L, the total membrane resistance was the least.