| In recent years, as China's urbanization process accelerated, small towns develop very quickly, wastewater and effluent discharge is increasing dramatically, but the relatively weak economic level has been a limit for the great amount of devices for wastewater treatment. The bio-flocculation and adsorption intensified primary treatment is a definite trend to develop high-efficient municipal wastewater treatment technology with economic feasibility and sustainability for small and medium-sized towns.The effect of AOA / bio-contact oxidation for municipal wastewater was studied in this paper based on bio-flocculation and adsorption intensified primary treatment. During 6 months, the HRT and F/M of flocculation and adsorption basin have been chose as experimental parameters. For each parameter, three levels have been chose and 9 different operational conditions have been studied.Results showed that the removal effect of the AOA was stable and reliable as a whole under the flux is 1～2m3/d, the dissolved oxygen of recycling basin is 2mg/L, dissolved oxygen of flocculation and adsorption basin is 0.5mg/L, dissolved oxygen of anaerobic tank is 0.2mg/L, sludge age is 8 days,circumfluence ratio is 100%, the air-water ratio is 5:1,F/M of the flocculation and adsorption basin is 2.8 kgCOD/(kgMLSS·d)and the HRT is 1.0h. The average removal ratio of TN and TP could be as high as 36.26% and 43.80%. The system could be reach 45.24% and 50.68%.The effect of part B upon denitrification was complement to AOA's. the particle P removal effect of the part B was remarkable.Dephosphorization in AOA was supported by traditional dephosphorize mechanism and denitrification dephosphorized mechanism. Denitrification took place in both AOA and part B. Two phenomenons occurred in phase.Different HRT of flocculation and adsorption basin and quantity of circumfluence made different quantity of contamination which sludge adsorbed. There were peak values of dephosphorization and denitrification in certain range. When the HRT of flocculation and adsorption basin is certain, along with accretion of F/M the peak value moved forewards.According to the model of Echenfelder under low level of organic matter concentration-response relationship, the dynamics model of degradation organisms of bio-flocculation and adsorption intensified primary treatment was deduced, empirical evidence showed that the established model can be used to predict the concentration of COD.The model was : The removel of dissolved phosphate follow the equation In 5th condition TP removel is best. Results showd that Regressive equation of AOA is y=1.01774x-0.9536,R2=0.8003; Regressive equation of anaerobic tank and recycling basin is y=1.2897x -1.2583,R2 is 0.8067.The experimental results showed that AOA compared with bio-flocculation and adsorption intensified primary treatment to purify municipal wastewater has a higher ability of removal of organisms and suspended substances,better removel of nitrogen and TP.
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