| 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 water pollution treatment. So it is a definite trend to develop high-efficient municipal wastewater treatment technology with economic feasibility and sustainability for small and medium-sized towns. The municipal wastewater intensified primary treatment can reduce bigger pollution load, slows down the water environment pollution. Environmental pollution aggravation and the economy level of development have decided that in quite a long time, the intensified primary treatment will be an important way for wastewater treatment in small and medium-sized towns.Experiment on the bio-flocculation and adsorption intensified primary treatment / bio-contact oxidation for municipal water with the designed device was studied in this paper. Six operating conditions are studied in eight months'experiment: Hydraulic Retention Time (HRT) single factor experiment, Dissolved Oxygen (DO) of recycling basin single factor experiment, sludge loading of flocculation basin single factor experiment, Sludge Retention Time of intensified primary treatment single factor experiment, air-water ratio of bio-oxidation basin single factor experiment, water temperature single fator experiment.The results showed that the removal effect of the combined technics was better under the condition of Q=1.5m3/d, DO of recycling basin 2.0mg/L, the mix intensity of flocculation and adsorption basin 60 revolution per minute, sludge loading 3.6kgCOD/ (kgMLSS·d), sludge return ratio to 60%, the air-water ratio 5:1, sludge age 15 days, water temperature 30℃, The average ratio of SS, COD, NH3-N, TN and TP were 88.7%, 89.3%, 87.9%, 73.4% and 58.8% respectively, all indexes could reach the level B of first standard of《The concentration of available discharged effluent from wastewater treatment plant in town》(GB18918-2002) excepted phosphorus. Its intensified primary treatment, the average removal ratio of COD and SS could be as high as 72% and 76%, and the removal effect of nitrogen was remarkable, thus reduced the load of the follow-up treatment greatly.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 :It showed that through experiment of bio-flocculation and adsorption intensified primary treatment / bio-contact oxidation integrative reactor to municipal wastewater, this technology has a high ability of removal of organisms,suspended substances and nitrogen. The advantages of the reactor is requiring a smaller land area,low investment,saving energy and convenient management. So it is an integrative reactor with high efficiency and low consumption that can be widely used in small and medium-sized towns. |
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