The Optimization Experiment Study On Disposing High Ammonia-nitrogen Wastewater By Dynamic Biological Membrance Method And Sequencing Batch Reactor

Aiming at high ammonia-nitrogen wastewater which has large emissions, complex compositions, high toxicity and great harm to the environment at present, SDMBR reactor(Sequencing Dynamic membrane bio-reactor) and SBR reactor( Sequencing Batch Reactor) are adopted. starting and operating them under the same condition, to observe and analyze the treatment effect of two reactors on high ammonia-nitrogen wastewater.Firstly,the preponderant fungus processing high ammonia-nitrogen was cultured by increasing concentration of influent ammonia-nitrogen gradually and domesticating sludge in SDMBR reactor and SBR reactor respectively.It takes 30 days for the SDMBR reactor’s successful start and 48 days for another. And when the concentration of NH4+-N was increased to about 130mg/L, its removal rate can reach to above 90%.Secondly, the operating conditions of these two reactors should be controlled as follows:the aerobic dissolved oxygen concentration of 2~4 mg/L, the anaerobic dissolved oxygen concentration of 0.2 ~0.5 mg/L, the water temperature of 20~23℃,the influent pH of 7~8 and the activated sludge concentration of 2.8~5 g/L. In this condition, when the influent COD and NH4+-N concentrations changed respectively between 508.7~672.3mg/L and116.3~142.5mg/L, the average removal rates of COD, NH4+-N and TN by using SDMBR reactor were 94.64%, 95.31% and 77.62%, and 90.09%、87.59%、72.48% for SBR reactor.Therefore,Compared to SBR reactor, the SDMBR removal rate of COD, NH4+-N and TN are relatively high.Thirdly, the suitable conditions in processing high ammonia-nitrogen wastewater were obtained through the single-factor experiment of SDMBR reactor, namely MLSS of4000~6000mg/L, DO of 2~4mg/L, HRT of 12h~18h and pH of 7~9.Finally, through orthogonal test and range analysis to HRT, MLSS, DO and pH, the experiment obtained that, according to influence degree, the 4 above-mentioned factors influencing on COD removal rate were sorted by HRT, MLSS, DO and pH in descending order, and the operating parameters of HRT, MLSS, DO and pH were 18 h, 5g/L, 4mg/L and 8respectively. While the descending order of those 4 factors influencing on NH4+-N removal rate was followed by pH, DO, HRT and MLSS, and the operating parameters of pH,DO,HRT and MLSS were 8, 4mg/L, 15 h and 5g/L. Thinking about the range analysis of the removal rate of COD and NH4+-N comprehensively, the optimal operating parameters of dynamic membrane bioreactor were pH of 8, DO of 4mg/L, MLSS of 5g/L and HRT of 15 h in processing high ammonia-nitrogen wastewater.