The Study Of Simultaneous Nitrifiction And Denitrification Via Nitrite By RBC

While plenty of wastewater has been drained into waters, ammonium contamination of water environment which is responsible for eutrophication is been fully aware of the gravity of the question. Removal nitrogen is the emphasis and one of the points of issues in the studies of water pollution. Among the nitrogen removal methods, such as physical methods, chemical methods and biological methods, biological denitrification is considered as a kind of the best treatments. At present, because it is the most efficient, lower investment, simple, no secondary pollution. How to remove nitrogen efficiently and reasonably is central issue wastewater treatment realm worldwide. There are two developmental stages for biological treatment. Before the 70's of the last century, the effluent contains a large amount of nitrogen, phosphorus with the conventional activated sludge method which mainly remove the organic pollutants of carbon BOD. After 20Th century 70's, some improved activated sludge methods which focus on nitrogen and phosphorus removing has been developed.According to the traditional denitrification theory, biological denitrification is made up of two pieces of process. One is nitrify by nitrifier under aerobic condition, the other is denitrify by denitrifier under anaerobic condition instead. But in recent years, some reseacher have found a lot of phenomena beyond the traditional realization in biological denitrification, such as nitrify process not only can be participated by autotrophic microorganism but also by heterotrophic microorganism. The denitrification process not merely go on under anaerobic, but also in aerobic condition by some bacteria. Inmicrobiologic studies, aerobic denitrifier, also as heterotrophic nitrifier , can oxidize ammonium to nitrate, then react directly. Such new ideas break down barriers of nitrifiers and denitrifies, thinking that NO2--N can be utilize by aerobic autotrophic bacterium as electronic receptor under oxygen limiting conditions. Those discoveries and experiment facts suggested some new theories and ideas for the workers of wastewater treament. Simultaneous nitrification and denitrification-SND is a kind of new concept and technique with challenge. SND means that nitrification and denitrification can take place concurrently in one vessel at the same operation conditions. As SND combine with nitrify and denitrify together in the same reactor, thus technological process may simplify and reduce cost. Because the product of nitrification can react directly by nitrifier, thus it may avoid inhibition of nitrite accumulation for nitrification and increasing nitrifying amount. Therefor SND as a kind of economical, reasonable, efficient technique has a well-developing prospect. Once this kind of low energy consumption, high efficiency method come into operation, the eutrophication of the water body will be controlled more effectively.The domestic and international researchers have obtained many experimental results about SND. But the understanding is still not very clear about SND concept, mechanism, occurrence path, affecting factors, application method. As a new standpoint, we must do a flood of research work to verify its theory's accuracy and actual applied possibility, make further study and developing research. This contributes to apply the nitrogen removal technology to actual treatment. Solve this problem help SND technologyapplication to the actual project.Based on the latest research foundation of domestic and abroad, SND have been studied by single stage rotation biological contactor (RBC) and carried out the reactor start-up, running and sludge domestication of the investigation successfully. The experiment goes forward into the steady circulating stage and has got SND via nitrite successfully. The experiment has been entered steady operation stage basically and realized SND via nitrite successively. In this thesis, the effects of ammonium load and CODc/NtV-N ratio of SND have been studied. In SND process, the author found the factors effecting nitrite accumula...