Study On The Treatment Of Domestic Wastewater By The MBR Process Of Suspension Carrier

Membrane Bioreactor(MBR)is a combined biological treatment with membrane separation technology of water treatment technology,a highly efficient and stable technology.The compound MBR process is to add suspension carrier to bioreactor,in order to improve the ability of handling system,is developing rapidly in recent years.However,the membrane fouling problem in MBR process limits the wide application of MBR process,resulting in increased operating cost.Therefore,it is the direction of MBR process research to study the problem of membrane fouling.In this study,a columnar suspension carrier was selected to form a compound MBR process in bioreactor.After the activation and domestication of the activated sludge in 30d,and the suspension of the suspended membrane of 18d,the compound MBR process was started,and the optimization of operating conditions was studied.The results show that the optimal operating conditions are:HRT is 12h,the aeration volume is 9L/min,and the withdrawal time ratio is 9min:3min.Compared with the MBR process of compound MBR and the process of non-dropping suspension carrier,the treatment effect of COD and ammonia nitrogen was shown.The removal rate of COD was increased by 3.4%and ammonia nitrogen removal rate increased by 4.3%.The optimum dosage and the applicable activated sludge concentration conditions were studied The results show that the suspension carrier has a slow effect on the membrane fouling of MBR mud cake,and the high sludge concentration conditions are more suitable for the suspension carrier,and 20%of the suspension carrier has the best effect.Under the condition of low sludge concentration,20%of the injected amount slows the membrane fouling effect,and TMP can decrease by 9.3 kPa.Under the condition of high sludge concentration,the TMP drop can reach 14.9 kPa.The suspension carrier has a significant effect on the improvement of MBR wastewater treatment.Removal rate of COD removal rate up to 95.1%,and ammonia nitrogen removal rate up to 97.3%,removal rate and high sludge concentration under the condition of treatment effect is better than that of low sludge condition.The increase of TN removal rate was not significant,and the TP removal rate increased by nearly 10%.The mechanism and optimization of membrane fouling were studied.Using bioreactor to stop the water out of the water to maintain air aeration,reduce sludge concentration in the bioreactor and prolong bioreactor stopped smoking three methods can make under the condition of low pressure filtration membrane fouling is a certain degree of recovery,the first method of contaminated membrane filtration ability recoveiy rate was the fastest,the pHase of the TMF decline rate is 1.3 kPa/d.The chemical cleaning method can reduce membrane fouling and effectively restore the flux of membrane.Water rinsing includes high velocity tap water flushing and low velocity hot water flushing-Two kinds of pickling agents were compared to choose oxalic acid for pickling and maintenance.After oxalic acid cleaining,the membrane flux was restored to 70%,and the effect was obvious.Finally,with sodium hypochlorite solution,the membrane flux was restored to about 96%,and the membrane fouling was obviously cleaned and mainained.