Study On The Effectiveness Evaluation Of Rural Sewage Treatment Systems And Its Adaptive Management In The Suburbs Of Shanghai

The small towns and rural sewage pollution is becoming more prominent, as urban sewage treatment rate rising. Study on the decentralized wastewater treatment under the social and economic development in rural areas has become the research focus in the field of rural water environment conservation and management. Moreover, study on the decentralized rural wastewater treatment of Shanghai suburban has important theoretical and practical significance to the large-scale rural sewage treatment project during the period of Shanghai Twelfth Five Years. From an integrated perspective of environmental engineering, environmental management and environmental planning, based on the investigation of sewage characteristics and emission behavior, the effectiveness of the typical rural sewage treatment systems was assessed and compared, combined with the current sewage treatment in rural of Shanghai suburban. And then, the key problems existing in the process was analysed and discussed. Finally, adaptive management strategies for rural wastewater treatment were put forward in thesis.The main results are as follows.(1) The household water using and sewage emission in rural was investigated to analysed sewage characteristics and emission behavior based on the household servey. Moreover, the factors that affect the sewage emission were futher analysed and compared. Research findings showed that:â‘ The pollutant concentration of rural sewage is lower, but more volatile. There is a significant difference between districts on pollutant concentrations, which is the highest in Fengxian District, and lowest in Chongming County.And then, the major pollutant concentration of CODCr, BOD5, NH3-N and TP shows a similar variation during different months, and the concentration of February, May and October is significantly higher than that of other months.â‘¡In general, the household water consumption is small, and the water peak periods are distributed in three phases on a day, which is earlier morning, midday and later evening, therefor, the characteristics of wastewater from household are intermittent discharge and unstable. Meanwhile, the sewage discharge will be also affected by sources of income, the immigrant population, seasonal changes and water charges.â‘¢Because of residents'living and habits and the immigrant population, the collection and treatment of various types of wastewater is different, which the flushing water and bathing water can be collected by the pipeline to the sewage treatment system, the majority of laundry wastewater is fugitive discharged due to the difficulties in collecting, and the treatment rate of kitchen wastewater is also low.(2) Based on the pilot project the effectiveness of the typical rural sewage treatment systems was assessed and compared. And then, the influencing factors were analysed and discussed. What is more, the classified technical guidance system of rural sewage treatment in Shanghai suburban was proposed as to the currently.diversiform treatment technologies and blind and random selection. Research findings showed that:â‘ Firstly, the selection technologies are technically applicable, but the removal efficiency of NH3-N and TP is relatively poor. Secondly, the cost is mucu higher due to the lack of uniform standards, which still needs to reduce to be better used in rural areas. Thirdly, the effectiveness of sewage treatment system is difficult to be guaranteed because of the lack of long-term management mechanism for sewage treatment facilities.â‘¡The effectiveness of sewage treatment system are both influenced by objective and subjective factors. The former includes rainfall and temperature, and the latter includes the not standard operation of feasibility demonstration of treatment systems, construction quality and operation and maintenance.(3) Adaptive management strategies for rural waste water treatment were put forward according to the complexity, based on the identification of the key issues and initial judgement of rural sewage treatment of Shanghai suburb in future. Research findings showed that:â‘ Fund input and source, technology applicability and normative, and maintenance management for sewage treatment facilities are the three key issues of rural sewage treatment.â‘¡It is thought that the decentralized and classified treatment is the main mode for the rural sewage that can not collected to the sewage treatment plant within a short time in the future, according to the rural development.â‘¢It is advised to construct organization of rural sewage treatment to clear government management system and responsibility distribution of all parties, encourage participation of social capital but the construction and operation mode by government is still leading. Then, establish the long-term management mechanism for sewage treatment facilities that evaluated by government, constructed and specialized enterprises, used and supervised by household. And then, real-time monitor the operation of sewage treatment system combined with the terminal water quality monitoring and procedure water quantity control. Last but not the least, the classified technical guidance system of rural sewage treatment in Shanghai suburban is preliminarily constructed from the six aspects of application conditions, site conditions, treatment scale, technical parameters, investment costs and management requirements to screen more appropriate technology for different districts.