| The rural population of our country is multitudinous, domestic sewage has large quantity of emissions, but the treatment rate is very low, which caused serious pollution to the environment. How to improve rural living environment under the premise of economic permission has become a problem urgently to be solved in China’s environmental protection department and the relevant workers.According to the characteristics of rural domestic sewage quality, we constructed the test device of stabilization pond system. We studied the contaminants changes, the mud properties and the biological phase changes during the start-up period of the system; In the stable operation period of the system, we studied the aeration time of aerated pond, the water plant species of aerobic pond and the packing type of strengthen anaerobic pond on the treatment effect of the system, we focused on the study of hydraulic retention time (HRT), carbon and nitrogen ratio (C/N) and temperature (T), we got the best operation parameters under laboratory conditions, investigated the pollutants removal efficiency of stabilization pond at all levels.In the start-up period, when the system run to the 11th day, COD removal rate has reached to 81.12%, with the increasing of operation time, the removal rate of COD stabilize between 94.07%～96.37%, the changes of NH3-N and TP concentration is similar, NH3-N and TP removal rate up to 68.97% and 77.38% at last, start-up period of the system is over.In stable operation period, we examined the pollutants removal effect of the system on aeration time of aeration pond is 3h,4h and 5h, respectively. The results showed that the average removal rate of COD in system were 88.8%,90.3% and 91.9%in turn, the average removal rate of NH3-N were 51.5%,64.7% and 68.9% in turn, the average removal rate of TP were 63.0%,72.9% and 83.8% in turn, combining the pollutants removal efficiency and running cost, it is advisable to use 4h aeration time; The results of the test on aerobic duckweed pond and aerobic water hyacinth pond showed that the water hyacinth’s removal efficiency especially to NH3-N and TP is better and more stable to duckweed. The average removal rate of CODx NH3-N and TP were 88.96%,52.48% and 64.06% in duckweed pond, in water hyacinth pond, the average removal rate of COD、NH3-N and TP were 92.13%, 73.94% and 84.17% respectively; In the contrast experiment of strengthen anaerobic pond respectively adding fly ash+red mud filler and modified organisms suspended filler, the average COD removal rate were 92.24% and 90.34%, respectively, the average removal rate of NH3-N were 69.50% and 65.90%, respectively, the average removal rate of TP were 84.17% and 64.06%, respectively, considering reuse of the wastes and depurative effect for contamination removal, the fly ash+red mud packing is better.In the condition of the aeration time in aerated pond is 4h, the aerobic pond planting water hyacinth and the strengthen anaerobic pond adding fly ash+red mud filler, we studied the pollutants changes in HRT of 11d,14d,17d,20d and 23d, respectively. The results showed that with the increasing of HRT, the removal rates of COD, NH3-N and TP were increasing, considering the removal efficiency of each pollutant, water stability and running cost, the HRT of the system is set to 17d. the average removal rate of COD, NH3-N and TP were 94.23%,74.39% and 94.23%, respectively; We compared the pollutants changes of C/N were 9,10,11 and 12, respectively, with the increasing of C/N, the removal efficiency of COD increased slightly, the removal efficiency of NH3-N increased more obviously, the TP removal effect had little change, when the C/N in system were 11 and 12, respectively, the pollutant removal ability has little difference, so we selected C/N of 11 in stabilization pond system. Removal efficiency of pollutants in stabilization pond was investigated under the temperature of 15℃,20℃ and 25℃, the results showed that the system had obvious removal effect on COD, NH3-N and TP under every temperature, considering the treatment effects on TP in temperature of 25℃ is slightly different to 20℃, we set the temperature of the system as 20℃.In the optimal parameters of HRT is 17 d, C/N is 11 and T is 20℃, we studied the pollutant removal efficiency in system. The results showed that the effluent of the system was stable and COD meets the first level of A criteria specified in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 19818-2002), NH3-N and TP meet the secondary level, in the degradation of COD, NH3-N and TP, stabilization pond at all levels give full play to their advantages in the implementation of effective removal of pollutants. |
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