The Study of Simultaneous Nitrifiction and Denitrification Via Nitrite by RBC
|Keywords||Rotating biological contactors Simultaneous nitrification and denitrification The accumulation of nitrite Sync nitrite nitrogen|
A large number of domestic sewage, industrial effluents and agricultural application of nitrogen fertilizer with runoff into the rivers, lakes and reservoirs, environmental pollution is worsening, it is because nitrogen is caused by eutrophication of the main factors. Removal of nitrogen pollution control industry is the focus of research and hot spots. Denitrification methods include physical chemical and biological methods, including biological treatment due to lower cost, simple process, low investment and operating costs, and no secondary pollution is considered to be one of the best approach. So how to cost-effective use of biological methods to remove nitrogen in water bodies at home and abroad the direction of research in the field of water resources control. Biological treatment of sewage have been two important stages: before the 1970s, the conventional activated sludge process and the subsequent development of the activated sludge process improvements. Conventional activated sludge wastewater degradation is mainly dominated by BOD organic, so there are still large amounts of nitrogen and phosphorus into the water; improve the activated sludge denitrification and phosphorus removal as a development focus. Traditional theory holds that denitrification, biological nitrogen removal process is composed of two components: the nitration reaction by nitrifying bacteria under aerobic conditions completed; denitrification by denitrifying bacteria under anaerobic conditions, complete. However in recent years, people in the study of biological denitrification found many beyond the traditional understanding of the phenomenon, such as nitrification process is not only completed by the autotrophic bacteria, heterotrophic bacteria can also participate in nitrification; denitrification under anaerobic conditions only, a These bacteria can also be carried out under aerobic conditions denitrification; research in microbiology that many aerobic denitrifying bacteria also heterotrophic nitrification bacteria (eg Thiosphaera pantotropha), and will make NH 4 sup>-N oxidized to NO 3 - sup>-N directly after denitrification. These new ideas to break the traditional theory of nitrifying bacteria and denitrifying bacteria strict boundaries that rigorous aerobic autotrophic nitrifying bacteria in oxygen-limited conditions can utilize NO 2 - sup >-N as an electron acceptor and for denitrification. The discovery of these phenomena and experimental facts water treatment workers with new theories and research ideas. Simultaneous nitrification and denitrification (simultaneous nitrification and denitrification-SND) is a challenging new concepts, new technologies, SND refers Journal of Guizhou Normal University - the same operating conditions, nitrification and denitrification in the same reaction vessel simultaneously. As SND will nitrification and denitrification combined in the same reactor, while achieving, making it possible to simplify the process, save processing costs. The nitration reaction product can be directly into the substrate for denitrification, to avoid the fly during the culture NOZ N accumulation inhibition of nitrification, accelerate the process of nitration. Therefore, as a fly economically rational energy efficient wastewater treatment technology, SND technology sustainable and broad, good prospects for development. Once this low energy consumption, low investment, high processing efficiency technology in use, will be more effective in controlling eutrophication. Domestic and foreign researchers SND research has made extensive laboratory research, but SND concept, mechanism, occurring pathway, influencing factors, to achieve the conditions as well as in other aspects of knowledge engineering applications is not very clear. SND as a new point of view or theory, a lot of research work remains to be done to verify its correctness or theoretical feasibility of practical application. The technology will help solve these problems in practical engineering applications. This topic based on biological nitrogen removal technology at home and abroad on the basis of a single-stage rotating biological contactor (RBC) bioreactor for biological treatment SND small laboratory tests. Currently the reactor has been completed start (ie SND reaction microbial culture), sludge acclimation work, testing into the stable operation stage, and successfully achieve the synchronization nitrite nitrogen. The experiment studied the ammonia loading, carbon, etc. on simultaneous nitrification and denitrification; analyzes NOZ a sup> reasons for the formation; using a series of chemical reactions in the theoretical derivation nitrification kinetics differential equations; degradation of organic matter derived kinetic model. The results showed that: in the biological turntable to achieve steady accumulation of nitrite and nitrite nitrogen sync and sync nitrite nitrogen through nitrogen removal around 19% of total nitrogen, which for high concentration, Low N Ratio Wastewater has significant advantages; SND process △ CODe secretin △ IN at 7 8 sup>, which a Master ten Guizhou Normal people Dissertation - denitrification theory method with conventional carbon sources considerable demand. Thus said, just from the △ CODC Ah △, IN view, SND is not a low-carbon source consumed in the process. SND suitable carbon source range may occur at 240 a 80mgcoDc few. Therefore proposed a one-time dosing nitrogen, carbon was added portionwise runs. Ammonia loading and hydraulic retention time affect ammonia removal. The higher ammonia loading, hydraulic retention time is shorter, the higher the effluent ammonia, ammonia removal efficiency is lower. Not only affects the carbon denitrification, but also affect aerobic denitrification. And CODC tie a state of biological nitrification than the type of product does not exist a significant impact. In this study, practice and theoretical innovations are: to achieve a long-term nitrite and stable accumulation, proposed the formation of bio-accumulation of nitrite nitrogen turntable system conditions; breaking the traditional understanding of the theory of biological nitrogen removal, carried out simultaneous nitrification and denitrification (SND) new biological nitrogen removal technology research; achieved by nitrite is synchronized simultaneous nitrification and denitrification via nitrite nitrogen.