Study On Technology And Mechanism Of Denitrification With Deodorization Process Of Decentralized Domestic Wastewater

In consideration of the pollution problems caused by domestic sewage In rural areas It's important to find the optimum solution of domestic sewage treatment,decentralized treatment technology with energy-saving,good efficiency and low investment.The research group of Southeast University proposed a bio-ecological combined process, anaerobic baffled reactor-anoxic deodorization tank-aerobic biological rotating disc(waterwheel driving)-constructed wetland. Through strengthening the aeration effect of waterfall aeration contact oxidation and refluxing nitrification liquid to the anoxic reactor to oxidate odor pollutant with nitrate, denitrification and deodorizing in Anaerobic reactor achieved Nitrate pollution and odor pollution in the process of sewage treatment. The process has the characteristics of low energy consumption and operating cost.The main conclusions are as followed:(1) In summer, the optimal reflux ratio of anoxic tank was 100%, the COD removal rate reached 49.3%, the total nitrogen removal rate reached 35.7%, the TON removal rate reached above 86%, the sulfide removal rate was 93.7%. When nitrate load was 18g/(m3·d) and dissolved oxygen was 2.7mg/L, the best denitification and deodorization effect can be obtained. The most optimal hydraulic residence time of contact oxidation pool in aerobic treatment was 4h,the dissolved oxygen in water was 5.14mg/L, the COD removal rate reached 42.3%, the ammonia nitrogen removal was 94.7%,the total nitrogen removal rate reached 33.5%,The removal rate of TP was37.3%, the sulfide removal rate was 58.9%.(2) In spring-autumn, low temperature inhibited the microbial metabolism. Increasing the reflux ratio can increase performance quality.The optimal reflux ratio of anoxic tank was 150%, the COD removal rate reached 50.3%, the total nitrogen removal rate reached 30.4%, the TON removal rate reached above 81.5%, the sulfide removal rate was 90.1%. When nitrate load was 25g/(m3·d) and dissolved oxygen was 3.2mg/L, the best denitification and deodorization effect can be obtained. The most optimal hydraulic residence time of contact oxidation pool in aerobic treatment was 6h,the dissolved oxygen in water was 5.12mg/L, the COD removal rate reached 41.6%,the ammonia nitrogen removal was 91.2%,the total nitrogen removal rate reached 32.4%,The removal rate of TP was32.6%, the sulfide removal rate was 59.1%.(3) In winter, affected by low temperature,the optimal reflux ratio of anoxic tankincreased to 200%, the COD removal rate reached 49.3%, the total nitrogen removal rate reached 35.7%, the TON removal rate reached above 86%, the sulfide removal rate was 93.7%. When nitrate load was 18g/(m3·d) and dissolved oxygen was 2.7mg/L, the best denitification and deodorization effect can be obtained. The most optimal hydraulic residence time of contact oxidation pool in aerobic treatment was 4h,the dissolved oxygen in water was 5.14mg/L, the COD removal rate reached 41.3%,the ammonia nitrogen removal was 92.3%,the total nitrogen removal rate reached 32.6%,The removal rate of TP was 36.7%, the sulfide removal rate was 56.5%.(4) The whole biological and ecoogical combined system can well treat pollutants, with the COD, ammonia, TN and TP concentration of effluent were 15.4-35.6mg/L mg/L, 1.3-4.8mg/L,4.8-12.1 mg/L,0.5-4.6mg/L,0.19-0.78mg/L respectively. The output quality can reach the effluent standard of A in First grade of GB18918-2002.(5) Microbiological characteristic of sludge in anaerobic baffled reactor (ABR) by high-throughput sequencing have been studied. The results showed that, under the following conditions of dosing seed sludge, continuous operation by improving the load by steps after 60 days, the biofilm could be successfully formed. In the process of start-up, the COD (chemical oxygen demand) removing rate was about 75%,and the pH value was about 6.35-7.05. The dominant community in granule sludge was closely related to proteobacteria, bacteroidetes. In summer, chloroflexi. euryarchaeota?caldiserica?spirobacteria appeared in the sludge.The temperature play a significant role in the change of the primary sludge's microbial species.