Study On Key Enzyme Activities In MBR Nitrogen And Phosphorus Removal Process

Membrane bioreactor?MBR?is an organic combination of biological treatment technology and membrane technology,which has the advantages of efficient removal of pollutants,less residual sludge production,and high quality and stable effluent water quality.Become a new type of sewage treatment and reuse technology,and become a research hotspot of domestic and foreign sewage treatment technology.The research aims to conduct in-depth research on the changes of key enzymes?polyphosphate hydrolase,alkaline phosphatase and acid phosphatase?in the process of nitrogen and phosphorus removal.The operating conditions of MBR process was used to operate in anaerobic-aerobic?A/O?mode to examine different operations.Of MBR process on the removal rate of major pollutants and the change of key enzyme activities under the conditions.Of chemical removal rate and key enzyme activity changes.In addition,high-throughput sequencing of metagenomics was performed on activated sludge at various stages,and the microbial community characteristics and population differences in the MBR system were examined to detect and provide theoretical basis and technical guidance for the development and promotion of MBR nitrogen and phosphorus removal processes.The results show:The PPX enzyme play a role during the anaerobic phase.The optimum temperature is between 15?20?,and the removal rate of TP and NH₄⁺-N decreases by29.46%and 23.27%with increasing temperature;the optimum p H value is From 7.5to 8.0,the removal rate of TP and NH₄⁺-N increased by 24.01%and 23.16%with the increase of p H.Acid phosphatase play a role during the aerobic phase.When the temperature increased from 15?to 30?,the enzyme activity gradually decreased,and the removal rates of TP and NH₄⁺-N also decreased by 34.76%and 23.41%,respectively;when the p H increased from 6.5 to 8.0,the activity gradually When the p H was 6.5,the removal rates of TP and NH₄⁺-N decreased by 16.72%and 17.97%,respectively.Alkaline phosphatase play a role during the aerobic phase.The optimum temperature was 20?25?,and the removal rate of TP and NH₄⁺-N,which had the worst nitrogen and phosphorus removal capacity at 30?,decreased by 36.26 and21.70%respectively;the optimum p H was 7.5 With the increase of p H 8.0,the removal rate of TP and NH₄⁺-N increased by 22.98%and 36.97%,respectively.When the dissolved oxygen concentration was 0.3mg/L for a long time,the activities of all three enzymes were inhibited,and the system's ability to remove nitrogen and phosphorus was poor.There were no obvious changes in the three C/P enzymes.When C/N was 100/12,the activities of all three enzymes were inhibited.The phylum level is mainly based on microorganisms of Proteobacteria,Candidatus Saccharibacteria,Bacteroidetes,and Chloroflexi.The richness of the four accounts for 87.61%and 89.09%of the total bacteria.The major?-proteobacteria and?-proteobacteria are two larger floras in the phylum Proteus,and these two floras play an important role in the systematic removal of nitrogen and phosphorus.