A Comparative Study On Microbical Energy Metabolism Between Reversed A~2/O Process And Conventional A~2/O Process

Water pollution and eutrophication in China are extremely serious, which have becomemuch-watched global issues in recent years. Causing eutrophication fundamental reason isthat high content of nitrogen, phosphorus and other nutritive substances are in water,especially with wastewater discharged into water, so the fundamental way to solveeutrophication is the effective control emissions of urban sewage nitrogen, phosphorus andother nutrients. The wastewater treatment technology of municipal wastewater biologicalnutrient and phosphorus removal has gradually become a hotspot research in the field ofsewage treatment.Reversed A~2/O process has been proven by practice mature technology of nitrogen andphosphorus removal efficiency efficiently. Previous research had shown that nitrogen andphosphorus removal and operation energy consumption of the reversed A~2/O process wassignificantly better than conventional A~2/O process, but the two processes in microbialmetabolic activity and energy metabolism have not been clear on the difference, especiallymicrobial metabolic activity and energy metabolism studies have not been carried out indifferent C/N/P influent of the two processes. Therefore, this thesis explored differences ofmetabolic activity and energy metabolism of microbial communities in reversed/conventionalA~2/O process systems under different C/N/P influent, in order to provide the basis for thecause of the difference between two processes nitrogen and phosphorus removal throughmaking micro-mechanism clearly in the reaction.The main results showed that:(1) The pilot scale experiment showed that: In the removal effect of organic pollutantsand nitrogen respect, whether C/N/P influent, the reversed A~2/O process system was slightlybetter than conventional A~2/O process, and reversed A~2/O system compared with conventionalA~2/O system had better denitrification capacity; In phosphorus removal effect respect,whether C/N/P influent, the reversed A~2/O process system was superior to conventional A~2/Oprocess, especially in an insufficient number of low carbon C/N/P influent conditions, theadvantage of phosphorus removal in reversed A~2/O was more significant. Therefore, thenitrogen and phosphorus removal performance in reversed A~2/O process exhibit broaderapplicability under carbon C/N/P influent conditions, and reversed A~2/O process systemshowed more prominent advantage than conventional A~2/O process in low ratio of influentC/N/P.(2) Nitrogen and phosphorus removal mechanism of static process test results showed that: In the nitrogen removal mechanism respect, the test results showed that no matter whatC/N/P influent, the average specific nitrification rate and denitrification capability of reversedA~2/O process system are superior to that of conventional A~2/O process system, then got abetter effect of nitrogen; In the phosphorus removal mechanism respect, the test resultsshowed that no matter what C/N/P influent, phosphorus removal efficiency of reversed A~2/Oprocess system is superior to that of conventional A~2/O process system. PAOs in reversed A~2/Oprocess released phosphorus in anaerobic zone, then directly access to high biochemicalefficiency of the aerobic environment. Phosphorus-uptake motivation that formed underanaerobic conditions avoided inefficient consumption in anoxic zone and phosphorus-uptakepower was more fully utilized, thereby improving the phosphorus removal efficiency, and thisadvantage was more prominent in a low carbon influent C/N/P.(3) The microbial metabolic activity under aerobic condition and the overall level ofenergy metabolism during the operation of the static test procedure could be seen: no matterwhat kinds of C/N/P influent condition, metabolic activity (TTC-DHA activity, INT-ETSactivity and PPK activity) and energy metabolism of microorganism in reversed A~2/O processsystem are better than that in conventional A~2/O process system, which affected bytemperature less than the latter. Microorganisms in reversed A~2/O process system producedemergy and metabolism inefficiently under anaerobic conditions, then directly accessed tohigh biochemical effect and production efficiency of the aerobic environment: On the onehand, the total energy metabolism of microorganism was at higher level, on the other hand itenhanced the microbial metabolic activity as well as the ability of carbon sources utilization,and then got the removal capacity of organic pollutants and nitrogen and phosphorusincreased significantly.