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Research On Nitrogen And Phosphorus Removal Characteristics And Microbial Action Mechanism Of Step-Feedmultistage A/O Process

Posted on:2018-08-30Degree:MasterType:Thesis
Country:ChinaCandidate:X D QianFull Text:PDF
GTID:2321330515480946Subject:Municipal engineering
Abstract/Summary:PDF Full Text Request
The removal efficiency of nitrogen and phosphorus and the release of N20 in greenhouse gas during the sewage treatment process are two important problems in the sewage treatment process. Therefore, it is the main way to solve the above two problems by modifying the existing process or developing the new process. Multi-stage AO process through the intermittent aeration not only save aeration energy consumption also improved the efficiency of nitrogen removal, sub-water multi-stage AO process to avoid the organic carbon in the aerobic oxidation of the drawbacks, improve the efficiency of carbon use, to further improve The nitrogen removal efficiency, so sub-water multi-stage AO process in sewage treatment has obvious advantages. In this paper, the multi-stage AO process was used as the object of study and the different influent methods were used as the means of comparison. The effects of nitrogen and phosphorus removal and the release characteristics of N2O in the multi-stage AO process were studied. On the basis of this, the ecology principle of segmented influent and single-point influent nitrogen and phosphorus removal efficiency and N2O emission difference was analyzed from the ecological point of view,and the dynamic transformation of microbial community structure in the two reactors was micro Analysis.Using multi-stage AO and sub-water AO process, running two sets of 6L SBR, regularly monitor the reactor water quality. The reactor is 4 cycles per day and one cycle is 6 hours. Control sludge age is 15 d. (COD) of 200 mg/L with low C/N wastewater, ammonia nitrogen (NH4+-N) of 40 mg/L phosphorus(PO4-P) concentration of 10 mg/L. After the reactor has been stabilized, the operating conditions of the two reactors in a typical SBR cycle are studied.According to the long and periodic operation monitoring results, the pollutant removal effect and removal characteristics of the two reactors are compared.The concentrations of ammonia nitrogen, phosphate and nitrite in the effluent of the multi-point influent and single-point influent reactor were all lower, the nitrate concentration was higher, and the nitrate nitrogen in the multi-point influent reactor was significantly lower than that of the single point Water reactor. The total nitrogen removal rates of single point influent and multi -point influent reactor were 88.38% and 75.80 respectively, and the multi - point -influent reactor was 14.24% lower than that of single - point influent reactor.Under the two influent modes, the phosphate removal rate was over 97%.Under the same conditions, the multi - stage AO system was realized by changing the influent mode, and the TN removal rate was 18.7% higher than that of the AO system. The nitrification and denitrification of nitrification and simultaneous nitrification and denitrification occurred in the system, and the denitrification was mainly carried out by using endogenous carbon source. The denitrification activity of the activated carbon was higher than that of the activated carbon low.The multi - stage AO process can improve the denitrification efficiency of the system and reduce the generation and release of N2O. The NOB activity of activated sludge was significantly inhibited under the condition of sub-heading water, and the denitrification activity was higher than that of activated sludge with single point influent. The N2O production and release in the nitrification and denitrification processes are low and the simultaneous nitrification and denitrification processes are higher. The release and release rate of N2O released from activated sludge under the condition of multi - point influent is slightly higher than that of domesticated activated sludge. The addition of nitrite resulted in an increase in the amount of N2O produced and the release rate, and nitrite had the greatest effect on the denitrification process of endogenous carbon. Independent of the N2O emission characteristics of long-term domesticated activated sludge, the multi-point influent operation mode can effectively achieve N2O reduction in the short term.Analysis of flora strtructure shows that the microbes in activated sludge are mainly Proteobacteria, Bacteroidetes and Planctomycetes. Which is the most abundant door in the activated sludge, Nielson et al. (2010) research also reached the same conclusion. Nitrospira and Nitrospira are the major nitrifying bacteria; Azonexus and Dechloromonas are the main denitrifying fungi;Acinetobacter and Dechloromonas are the most important phosphorus-removing functional isolates.
Keywords/Search Tags:multiple AO, step-feed, nitrogen and phosphorus removal, N2O release, microbial population
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