Study On The Small Town Sewage By The Combination Of Biofilm And Artificial Floating Island

With the current situation of domestic sewage treatment in small town that numerous, sites are scattered, wide distribution and the lack of relevant standards and norms, which makes the integration technology of decentralized wastewater treatment possible. The method of biological contact oxidation has the advantage of strong capability of resistance to shock loading, the little yield of sludge, easy to solid- liquid separation and no sludge bulking. The degradation of the pollutants in wastewater that are rich in nitrogen and phosphorus occurs by using the ecology principle in the technology of artificial floating island, which can make the living room for the bird, fish and beauty the environment at the same time. The device combine the method of biofilm and artificial floating island together and can provide parameter for design and run through the moderate pilot test.The results of this study are as follows:(1)The best gas water ratio of the combination device is 3.5mg/L, the best feed water flow is 0.24m3/h, in this time the gas water ratio in suspension module and gas module are respectively 10 and 17.1, the removal rate of NH3-N, TN, COD, SS can reach respectively 82.25%, 48.49%, 79.29%, 96.22%. The above indexes reach the City of mixed water quality standards, meet the needs of urban reclaimed water reuse; the combination device replace the traditional secondary sedimentation tank of gas module, the removal rate of SS for effluent water can reach 96.22%, and the effect is stable; the combination device has strong impact resistant capability, the unit can run stably for a rapid recovery in response to water impact cases. New packing film speedily, which have high efficiency. Less sludge in the combination device is produced lead to no sludge bulking, which save the cost of sludge collecting and sludge discharge. The plant in the system grow well, its root developed which provide better growth environment for the microbial, the plant has the landscape value at the same time.(2)As to the problem of high phosphorus concentration in effluent of the device, we adopt the method of the chemical phosphorus removal, we choose the FeSO4 as phosphorus removal agent that is put into the system in the front of the device. The result of the study shows that with the help of auxiliary chemical phosphorus removal, the phosphorus removal capability of the device is greatly increased, The molar ratio of Fe/TP is 2; the phosphorus concentration in the effluent has reach the level one A standard of urban sewage treatment plant pollutant discharge standard, which improve the function of the device.(3)The combination device has better effect of sludge reduction, the average sludge production rate is 0.01kgMLSS/kgCOD that is about 1/10 to the conditional activated sludge process, save the cost of sludge dispose, reduce the running cost.(4)The total investment of the moderate pilot test project is ￥126300, the water treatment cost is ￥11.63 per ton, if we remove the staff’s’ salary, the water treatment cost is ￥3.1. We should take more positive steps to raise money for the small town sewage wastewater treatment project, the government should provide more support for small town wastewater treatment project in policy and legal aspects.