Experimental Research On Reactor Of Intermittent Aeration Complete Mix Activated Sludge Process

Completely mixed activated sludge process was characterized for strong impulsion load resistance, good treatment effect, simple process and convenient operation. Through the extension of sludge age, can achieve extended aeration, with less residual sludge, good stability, no longer need to carry out anaerobic nitrification treatment, also the initial sedimentation tanks can be omitted. However, as the requirements of effluent quality enhancing, removal of organic pollutants and denitrification are required. So the completely mixed activated sludge process can not meet the requirements, and its application subject to certain restrictions.Assimilating the advantages of completely mixed activated sludge process and anaerobic-aerobic process, we devised the integrated intemiittently aerated activated sludge reactor. By changing the reactor's flow cycle and operating mode, the process can achieve effective nitrification/denitrification and organic matter removal without sludge expansion.In this paper, the reactors performance of urban sewage treatment were studied, mainly inspected some factor's effects on removal of organic pollutants and denitrification concluding HRT , the ratio of aeration-unaeration and the time of aeration-unaeration. And then ascertain the optimum operation conditions. The experimental results showed that: HRT = 15h ,the ratio of aeration-unaeration= 3:1, the time of aeration-unaeration=60min, is the optimum operation condition; When the influent COD_Cr 96.38～337mg/L, TN 34.2～65 mg/L, SS 99～241mg/L, the concentration of effluent sewage can meet the first level standard of "Discharge standard of pollutants for municipal wastewater treatment plant" (GB18918-2002).Furthermore, to the optimum operation condition, the reactor disposed the UASB effluent of pretreatment by MAP. The reactor of effluent sewage COD_cr, NH⁺₄-N, TN can meet the first level of B standard about "Discharge standard of pollutants for municipal wastewater treatment plant" (GB18918-2002).At last, through research on Principle of biological treatment, the paper established expression of dynamic equations about organic matter removal and nitrogen removal.The integrated intermittently aerated activated sludge reactor has a high ability of organisms and nitrogen removal. In addition, the process still possesses the advanta ges of high effluent quality, low energy consumption, concise process, operation conveniency and so on, and it will be widely used in municipal sewage treatment.