～(15)N-identified Experimental Research On Biological Denitrification In The Wastewater And Analysis Of Biological Denitrification Process

With the rapid development of industry and agriculture, water body has beenincreasing polluted. Strengthening sewage disposal, controlling nitrogen, phosphorusnutrition material enter water body to prevent main way of water pollution from. Thebiological N and P removal technology has been used successfully to treat a variety ofpollutants, particularly effective in nitrogen removal from wastewater. In China, mostof the municipal wastewater is still treated with traditional methods, which can onlyremove organics (COD). In addition, most of the municipal wastewater plant runsunstably, and the level of automatic control is still lower. This dissertation studies themechanisms and processes of biological nitrogen removal from municipal wastewater.And presents the plant experiment technique reference and theory in the stagedplanning and reconstruct. Laboratory experiment used N isotope identification technology to study the 15process of microbial denitrificatio. The result showed that the δ15N of residual nitrateand the bacterial body increased in manual configurating nitrate culture which 15Nisotope when the denitrification acted. And gas, which had 15N isotope, had beenincreasing during the process of denitrification. The research proved that the δ15Nvalue was very effective to determine the qualitative and quantitative relationship,which affords practice experiment technique and theoretic method to the research onthe wastewater denitrification. Two wastewater processing plants in Beijing were selected to do producingexperiment and denitrificate application analysis. The result showed that the TKNremoval efficiency was different between two plants, although they have the sameA/O nitrogen removal process. They have different return sludge system and structureof the oxidation bank. The dissolved oxygen and organic loading have moresignificant effects on nitrogen removal efficiency. The TKN removal efficiency canincrease by increasing sludge return ration and decreasing sludge loading. Only BODloading is too slow, occurrence apt sludge expands. To protect good effluent, it is - II -ABSTRACTimportant to adjust operation according to change of influent. Furthermore, the dissertation discussed practice denitrification technique, andexplained simply, and prospected the future development.