Study On Domestic Sewage Treatment By Sequencing Batch Reactor With Assembled Type Packing Media

In this study, peltate packing and resilient packing were added into SBR system. The domestic sewage was treated by using the assembled type packing SBR and a comparison with traditional SBR was made. The study focused on the organic pollutants removal and nitrogen removal performance. The study is divided into four parts. In the start-up phase, the treatment performance of reactors was investigated and compared. Secondly, the optimal operating mode was defined. Thirdly, the effect of DO,initial pH,C/N on the domestic sewage treatment was researched. Fourthly, composite bacterial strains were added into three SBR reactors, the important studied point in this paper is effect of bacterial strains addition on the removal rate of organic pollutants and nitrogen of high concentration domestic sewage.The conclusions of this study were summarized as follows.(1) In the start-up phase, the NH4+ and TN removal rates of the reactor with peltate packing, the reactor with resilient packing and the reactor without packing are all escalating. After about one mouth time, respectively, the NH4+ removal rates are about 85%,81%,72%; the TN removal rates are about 85.2%,81.9% and 79.2%.(2) The optimal operating mode is determined as 1 h anaerobic stirring, 6 h aeration, following by 3 h anaerobic stirring, and then 2 h sedimentation and drawing. Under the optimal operation mode, the organic pollutants removal rates of the reactor with peltate packing, the reactor with resilient packing and the reactor without packing are about 96.7%,93.9%,90.6%; the NH4+ removal rates are about 95.8%,92.7%å'Œ90.4%; the TN removal rates are about 85.2%,81.9%å'Œ79.2%.(3) As increasing DO from 0.5 mg/L to 5.0 mg/L, the organic pollutants and NH4+ removal rates are all increasing. At DO value of 2.5mg/L, the average TN removal efficiencies of the three reactors are all best, which are 78.2% of the reactor with peltate packing , 74.0% of the reactor with resilient packing, 70.5% of the reactor without packing。(4) At the range of pH 6.0~9.0, the organic pollutants and nitrogen removal rates all increases firstly and decreases afterwards with increasing pH value. At pH value of 7.0, the organic pollutants and nitrogen removal efficiencies of the three reactors are all best, Moreover, the removal performance of assembled type packing SBR is better than the traditional SBR, and the reactor with peltate packing is best.(5) Adjusting C/N ratio from 4.0 to 12.0, the organic pollutants and NH4+ removal rates are decreasing as the C/N ratio is increasing, while the TN removal rate are increasing. At C/N ratio of 12, the TN removal rates of the reactor with peltate packing, the reactor with resilient packing and the reactor without packing are respectively 85.7%,83.5%,78.6%.(6) Adding composite bacterial strains into three SBR reactors can improve the effluent quality of high concentration domestic sewage. The treatment effects of different bacterial strains additions are researched. At the ratio of bacterial strains and sewage of 2/1000, the organic pollutants removal efficiencies are the best, which are 99.10% of the reactor with peltate packing, 96.62% of the reactor with resilient packing, 89.71% of the reactor without packing; at the ratio of bacterial strains and sewage of 5/1000, the NH4+ and TN removal efficiencies are the best. The NH4+ removal rates are respectively 99.22%,98.66%,93.98%, while the TN removal rates are 88.04%,84.64%,74.63%.