An Impact Stduy On Substanc And Energy Metabolism Between Reversed And Conventional A~2/O Process Under Different VFAs Proportion

With the explosion of the world’s population and the rapid increase of human activities,water shortage has become a global issue. As a result of the rapid development of theeconomy, more and more water reused without self-purification. With the excessiveexploitation of clean water and excessive emissions of sewage water, the water shortageproblem is increasingly serious. Because of the restriction of the geographical environment,the quantity-induced water shortage problem cannot be completely solved. Therefore, themain direction of solving the water shortage problem is to solve the quality-induced watershortage problem, and efficient sewage treatment is the basic way to solve the problem.Eutrophication pollution is one of the main harmful problems of the water pollution.Nitrogen and phosphorus need to be removed from the disposaled sewage to solve theeutrophication problem, and the common wastewater biological denitrification andphosphorus removal process is conventional A2/O process. But because of the specialarrangement form of the conventional A2/O process, synchronous biological denitrificationand phosphorus removal existes some insurmountable contradiction problems.According to the study of anaerobic, anoxic environment inversion effect and theanalysis of the experimental phenomenon of biological denitrification and phosphorusremoval, professor Zhangbo puts forward the reversed A2/O process. On the study basis of thereversed A2/O process, this paper researched the microbial substance metabolism and energymetabolism by changing the proportion of VFAs in the influent, in order to explore themicrocosmic basis of reversed A2/O process.The main results showed that:1)The denitrification and phosphorus removal performance results showed that:①Thepilot scale experiment results showed that: Different VFAs proportion in the influent had littleeffects to the ammonia nitrogen removal of the two processes; under the same VFAsproportion, the two processes had similar ammonia nitrogen removal efficiency, reversedA2/O process of ammonia nitrogen removal ability was slightly better. VFAs proportion in theinfluent had effects on denitrification ability of the two processes, the lower VFAs proportion, the more obvious advantage reversed A2/O process behaved on the denitrification ability.Under the conditions of100%or60%of the VFAs proportion, the phosphorus removal abilityof reversed A2/O process was superior to conventional A2/O process, especially under the60%VFAs proportion.②The static test results showed that: Under60%VFAs proportioncondition, the maximum specific nitrification rate and average specific nitrification rate ofreversed A2/O process increased by13.96%and16.87%compared with conventional A2/Oprocess;Under30%VFAs proportion condition, the two processes had similar specificnitrification rate. Under100%,60%and30%VFAs proportion condition, the specificdenitrification rate of reversed A2/O process increased by96.6%、83.2%and36.8%. Under100%and60%VFAs proportion condition, the aerobic phosphorus absorption rate of reversedA2/O process was lager than conventional A2/O process, while under30%VFAs proportioncondition, the aerobic phosphorus absorption rate of reversed A2/O process was lower thanconventional A2/O process.2）The microbial substance metabolism research results showed that: Under sufficient ormoderate VFAs proportion condition, the substance metabolism efficiency of the twoprocesses was very high, reversed A2/O process was slightly better than conventional A2/Oprocess, especially under the60%VFAs proportion. Under the60%VFAs proportioncondition, compared with conventional A2/O process, the utilization efficiency of PHAs, theutilization efficiency of the intracellular phosphorus metabolism and the utilization efficiencyof theintracellular glycogen of reversed A2/O process was respectively increased by11.1%,10.52%and10.44%.3) The microbial energy metabolism research results showed that: The comparative studyresults on DHA and ETS activity between the two processes under different VFAsproportion condition showed that:①Under100%and30%VFAs proportion condition, theDHA and ETS activity of the two processes was similar. Under60%VFAs proportioncondition, the maximum ETS activity and average ETS activity of reversed A2/O process wasrespectively increased by58.5%and39.0%compared with conventional A2/O process.②Under100%and60%VFAs proportion condition, the average and maximum ATP level under aerobic condition of reversed A2/O process was increased by10.2%and18.83%comparedwith conventional A2/O process.③Under100%and60%VFAs proportion condition, theaverage NAD+level under aerobic condition of reversed A2/O process was increased by6.35%and15.31%, and the NADH level was decreased by4.00%and13.61%compared withconventional A2/O process.