| With the rapid development of economy, gradually increased the proportion of sewage pollution of the environment, speeding up the process of urbanization, rural population distribution was more and more concentrated to the cities and towns,making smaller and the relative concentration of the sewage discharged to become one of the villages and towns sewage discharge mode. Sequencing batch reactor activated sludge process(SBR) has the advantages of simple process flow, low cost,good effluent quality, suitable for small and medium-sized sewage treatment plants, so SBR technology has become the first choice of small and medium sized sewage treatment plant. This study was mainly to explore the SBR treatment of domestic sewage in the process of operating conditions on the effect of nitrogen and phosphorus removal and microbial diversity change, to provide theoretical support for the application of SBR treatment of domestic sewage.This article discussed the different operating conditions, various stages of SBR system combination optimal operation mode; studied at different temperatures,TOC/N and carbon source conditions, changes in SBR wastewater treatment system effects; SBR system by changing the operating mode, explored microbial diversity changes under different operating conditions with high throughput technology. The experimental results as follow:The best combined operation mode of SBR system is instantaneous water-anaerobic(2h)-aerobic(5h)-hypoxia(2h)-precipitation(1h).Influent TOC/N of sewage treatment process has different effects on the removal of pollutants. When the influent TOC/N was more than 4:1, the system significantly reduced the dissolved oxygen content of the aerobic phase, leading to reduced nitrification rate of ammonia, nitrogen and affected the entire process. When TOC/N was 2:1 and 4:1, the removal rate of ammonia nitrogen was higher, reaching 62.7%.Temperature is an important influence factor of activated sludge process, when the temperature was 25 ?, 20 ? and 15 ?, the COD removal rate was 91.5% and90.1% and 80.4%, total nitrogen removal rate were 64%, 28.9% and 8.9%., theremoval rate of TP was 54%, 40% and 10%.Denitrification with methanol, ethanol, glucose, sodium citrate and soluble starch as organic carbon source, the results showed that microbial using different carbon sources for denitrification, and denitrification rate has obvious differences.The diversity of microbial population structure was not different in different operation mode, but the difference of microbial abundance was great. Different operation mode of Proteobacteria has been the dominant population, Bacteroidetes as a secondary dominant population. In all activated sludge samples in addition to Proteobacteria and Bacteroidetes Chloroflexi, Planctomycetes(floating mold) is also a relatively large dominance of the two bacteria.Under different operating conditions, the microbial abundance of nitrogen removal was significantly changed, and the diversity also produced a certain degree of change. SBR process in the process of nitrogen removal in Central Asia, bacteria and anaerobic ammonium oxidizing bacteria, anaerobic denitrification bacteria and aerobic denitrification bacteria exist at the same time. However, due to the harsh growth conditions, the content of anaerobic ammonium oxidizing bacteria was lower,and the content was highest, which accounted for 2.4% of the total amount of the total bacteria. The SBR system of aerobic denitrifying bacteria content is very high, in 8, 9,10 samples of aerobic denitrifying bacteria was significantly more than the anaerobic denitrifying bacteria in aerobic denitrifying bacteria and anaerobic denitrifying bacteria ratio were 1.5:1, 2.1:1 and 2.3:1, changes in different operation mode of aerobic denitrification nitrifying bacteria and anaerobic denitrifying bacteria proportion provides support for the realization of the process of simultaneous nitrification and denitrification under aerobic conditions, the SBR technology can effectively improve the nitrogen removal efficiency, shorten the reaction process more easily; in the process of nitrogen removal in first, 4 and 6 operating modes of aerobic time is only 3H low average 12.2mg/L nitrate accumulation, while denitrifying bacteria were obviously different, but the total nitrogen removal rate was low, the total nitrogen removal rate was 29%; second, 3, 5, 8, 9 and 10 modes of operation, becauseof nitrosobacteria And nitrifying bacteria content differences, resulting in nitrate nitrogen accumulation had bigger difference and the influence on the removal effect of nitrogen, which the 3, 5 and 10 under the mode of removal effect of nitrogen is relatively good, the removal rate of total nitrogen respectively 54.9%, 49.1% and60.2%, the 10 model under anaerobic denitrifying bacteria accounted for the proportion of denitrifying bacteria total at least, only 42%, but denitrification efficiency was the highest, which indicated that aerobic anti nitrifying bacteria in the large extent involved in nitrogen removal process. |
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