Modelling, Simulation Of Autotrophic Nitrogen Removal Processes

Because of intensification of nitrogen pollution, the waste water biological nitrogen removal technology has aroused the universal interest of the many countries. The waste water biological nitrogen removal already became one important research direction in the water pollution control field .autotrophic nitrogen removal technology is a novel promising biological nitrogen removal process and has the very high research value. If the model of autotrophic nitrogen removal can be constructed and corresponding simulating system can be developed, inevitably can enhance the design quality and operating efficiency of the waste water processing system.Based on a partial nitritation process mathematical model in the articles, the thesis established autotrophic nitrogen removal process mathematical model, which include partial nitritation process and anaerobic ammonia oxidation process, and implenent the mathematical model in Aquasim software. An anaerobic ammonia oxidation lab examination was simulated. By comparing the lab examination results and computer simulation results, proved that simulation models are effective to simulate ammonia oxidation process. Based on the analysis for major factors of operation of autotrophic nitrogen removal technology, the dynamic analysis of autotrophic nitrogen removal was done from several aspects: aeration intensity, hydraulic conditions, the influnent conditions, and the competition between heterotrphs and Anammox were studied.The hydrodynamic conditions influenced Anammox biofilm system little;on the contrary, they influenced CANON biofilm system large. Because the transfer of oxygen mass in CANON system is important factor, therefore the control on aeration intensity to the CANON system is very important. Dynamic influent conditions also lead to lower Anammox activity, these results from mainly the oxygen and inhabitation of nitrite. Anammox and other bacteria competes electrons donator and the acceptor also can lower its activity. First reactor of reactors systems play the buffer role, therefore the dynamic influent conditions do little harm to two reactors systems. In application, the two reactors system has advantage. Meantime, the study of dynamic analysis of autotrophic nitrogenremoval process can help to decide and conect the policy of automation.