The Study Of Two-Sludge Biological Denitrifying Phosphorus And Nitrogen Removal System

Because of aggravating water pollution, the design of municipal wastewater treatment processes must consider not only phosphorus removal, but also nitrogen removal. Current metabolisms deemes biological phosphorus removal and biological nitrogen removal are two different processs, which are independent and competitive.According to current metabolisms, biological phosphorus removal and nitrogen removal processes will have to face many difficult problems: the sludge age competition between phosphorus removing bacteria and nitrifier, the substrate competition between denitrification and dephosphatation, and so on. After study of literatures about denitrifying dephosphatation over recent years , author deems:1) Biological phosphorus removal and nitrogen removal processes are relative- independent and intersectant; 2)It is possible to combine biological phosphorus removal and denitrification processes to form a process.So, in this dissertation, the followings were studied:1)The effect of nitrate on phosphorus removal and rapid endogenous denitrification;2)How to make the denitrifying phosphorus uptake more than the anaerobic phosphate release. Relation between consumed-HAc,removed-TP and consumed-NO3－；3)Two-sludge biological denitrifying phosphorus and nitrogen removal system；4)Microorganism groups of Two-sludge system and bacterial metabolism；5)Metabolism of the biological denitrifying phosphorus and nitrogen removal process；6)Kinetic model of the biological denitrifying phosphorus and nitrogen removal process.The whole researchs of the dissertation were divided into five parts:1) The phenomenon of denitrifying dephosphatation was found in anoxic phase of the sequencing batch reactor(A/O/A/O), which operated by synthetic waste water in laboratory. It means there is denitrifying phosphorus removing bacteria(DPB) in the actived sludge of (A/O/A/O)SBR, which can provide constant sludge for the next study of denitrifying dephosphatation in laboratory;2) By experimenting with the sludge provided by(A/O/A/O)SBR, study the metabolism of denitrifying dephosphatation.3) According to references and the study results of the first two parts, author designed and operated a new sequencing batch reactor by synthetic wastewater. The new reactor is called biological denitrifying dephosphatation two-sludge system, which canremedy some shortcomings in current single-sludge systems.4) Microbiological experiments with the actived sludge which provided by two-sludge system were done;5) According to the study results of the forward four parts, author made a summary about the metabolism of denitrifying dephosphatation and theorized kinetic mode.According to the above study results, especially the steady operation of two-sludge system(2A/O+N 2SBR), it can be proved that denitrification and excess phosphorus uptake are relatively independent and intersectant biological processes. The overlap is that denitrifying phosphorus removing bacteria(DPB)which possesses the two bacterial metabolisms, could utilize nitrate as an electron acceptor for phosphorus uptake. The two-sludge system can not only combined biological phosphorus removal and denitrification processes to form a process in practical wastwater treatment , but also solved the main difficulties of current single-sludge systems:①the sludge age competition between phosphorus removing bacteria and nitrifier; ② the substrate competition between denitrification and dephosphatation. The effluent quality of two-sludge system is up to par with the first class of discharge standard of pollutants for municipal wastewater treatment plant(GB8978-1996).The study of this dissertation belongs to the scientific research (2001BA604A01) of Tenth Five-Year plan in China. Most of the researchs were done for the first time in China.The results of the reserchs have showed great prospect in treated water quality improvement , have laid the foundation for advanced study of metabolism of the biological denitrifying dephosphatation in china. The...