High-efficiency nitrogen removal and dephosphorization device and process method using multi-stage AO composite IFAS technology

Abstract

The invention provides a high-efficiency nitrogen removal and dephosphorization device and process method using a multi-stage AO composite IFAS technology. The device includes an AI anaerobic tank, anAII anoxic tank, an OI aerobic tank, an OII aerobic tank, an AIII anoxic tank, an OIII aerobic tank and a secondary settling tank. The device and method can improve the efficiency of nitrogen removaland dephosphorization, correspond to existing sewage plant treatment process, get rid of the limitation of use of land, facilitate the implementation of standard upgrade speed up the process of standard upgrade of the sewage plant and greatly improve the technical level of sewage treatment.

Description

technical field [0001] The invention relates to the technical field of sewage treatment, in particular to a high-efficiency denitrification and dephosphorization device and process method of multi-stage AO composite IFAS technology. Background technique [0002] In recent years, the Ministry of Environmental Protection recently announced the national "Pollutant Discharge Standards for Urban Sewage Treatment Plants" (Draft for Comment), which has added relevant indicators for special discharge limits. The main indicators refer to "Surface Water Environmental Quality Standards (3838-2002 )”, Beijing, Tianjin, Guangdong, Jiangsu, Zhejiang and other regions have successively issued local standards, and have successively carried out related work to raise the standard for Class IV water. The discharge index of quasi-IV water standard has stricter requirements than the "Pollutant Discharge Standard for Urban Sewage Treatment Plants" (GB18918-2002), in which the special discharge li...

AI Technical Summary

Problems solved by technology

The main disadvantage is: the treatment efficiency is low, and the treated effluent comes from the nitrification tank, so the effluent contains a certain concentration of nitrates. If the sedimentation tank is not operated properly, denitrification will also occur in the sedimentation tank, causing the sludge to float. Afterwards, the quality of the effluent deteriorates. In addition, if the denitrification rate needs to be increased, the reflux ratio of the mixed solution must be increased, which will inevitably increase the operating cost. At the same time, the reflux of the mixed solution comes from the aerated nitrification tank, and the sewage contains a certain amount of dissolved oxygen. It makes it difficult for the denitrification tank to maintain an ideal anoxic state, which affects the denitrification reaction, and it is difficult to further improve the denitrification effect. The general denitrification rate is 70% to 80%. Within a certain limit, the phosphorus removal effect is not easy to improve, especially when the BOD / P value is low

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