The Fudemental Study Of Nitrogen Removal Via Nitrite By Real Time Control Using SBR Reactor

Biological nitrogen removal via nitrite is a new biological nitrogen removal process. Compared with traditional biological nitrogen removal technology, this new process can save aeration energy and denitrification carbon source, and it can also yield less waste biomass during treatment process, so it attracts more and more attentions all around the world. But the achievement of the new nitrogen removal process is very difficult, and it is more difficult to maintain high nitrite accumulation rate during ambient conditions for a long time. According to these features, the research focused on the achievement, maintenance, real time control and the feasibility of nitrite accumulation under real time control conditions. SBR reactor was used to treat real domestic wastewater during the research progress.Online parameters of pH and COD concentration were relevant during the process of organics removal by SBR reactor. We could adjust aeration in time according to the changing features of pH curve and optimize the aeration time. The relevance between pH and COD concentration was stable and not affected by aeration rate. But the changing temperature could weak the relevance, because temperature could affect pH value directly. By establishing a simpled kinetics model of organics removal we could know that the initial period of COD removal obeyed the first-order reaction and the later period of COD removal obeyed the second-order reaction. The interval between them was indistinct depending on conditions.By controlling the temperature (28±0.5℃) and maintaining the MLSS concentration (about 3100 mg/L), the bending-points of online parameters pH, DO and ORP were used to control the aerobic/anoxic alternation. The SBR reactor run for about 67 days and its nitrite accumulation rate (NO2--N/NOx--N) increased from 33.7% to 93.63%. The running model was changed from real time control to fixed time control, the nitrite accumulation rate in SBR decreased to 36.9% 7days later, and the main reasons was that the exact time of nitrification could not be controlled in time and the system was often in conditions of over aeration. The SBR reactor was operated under realtime control and normal...