水污染处理文献英文

1、Application of multi-soil-layer system (MSL in rural wastewater treatmentAbstract:with the continuous improvement of living in rural farmers, the waterconsumption of residents is increasing, rural sewage emissions will continue toincrease, if not treat effectively, the water environment in rural are

2、as will be seriousdeteriorated, and influence the life quality of rural residents. In this case this paperpresents a decentralized sewage treatment system, multi-soil-layer system technology(MSL application in the rural sewage treatment, this paper summarizes the newtechnology, youcan better underst

3、and and practice, especially in the developingcountrieswhereis in need of this technology. In the foreseeable future, it can protectpublic health and the sustainable development of theenvironment, and it alsoprovidesa new way for rural sewage treatment.Key words: rural sewage; multi-soil-layering sy

4、stem;distributed1. IntroductionIn recent years, with the continuous development of economy, people'sliving standards continue to improve, rural economic development is alsoveryrapid, but the rural economic development and environmentaldevelopmentis not synchronized, serious rural water pollution

5、.Whilehigh technicalsewage treatment plants, such as centralizedsewagetreatment plantsare involved in large investment costs, high operating costs,Because of economic constraints, such systems are less suitable for livestock farms and small communities in rural areas. Whilethe multi-media-soillayer

6、system(MSL sewage treatment system, this decentralizedsewage treatment system, it has less investment, low operatingcosts, high handling load. Besides, the utility model overcomes the defects of the prior soilpercolationwhich is easy to be blocked from the space structure.The sewage treatment system

7、 is one kind of the purification technology of sewerage treatment soil developed in Japan in twentieth Century, the soil system will be modularized, and the module is set up around the water in the soil layer to avoid clogging, and adding natural organic materials to soil modules can improve the pur

8、ification ability of the system.The MSL system consists of a Permeable layer (PL and a soil mixing layer block (SMB,The Permeable layer is usually composed oflarger particles fillers such as gravel, pumice, perlite and zeolite.Higher porosity can effectively prevent clogging of the soil water layer.

9、At the same time, the formation of aerobic environment is conducive to organic degradation.The mixed layer soil is mainly packing soil mixed with other 20%-30% other materials such as activated carbon, wood, iron and other material or soil with local resources.The organic material added in the soil

10、mixed layer can improve the biological decomposition and adsorption capacity of the system, and can also improve the supply of hydrogen in the process of nitrogen removal and promote the removal of nitrogen.There are many researches on MSL system treating urban sewage, livestock wastewater and river

11、 water at home and abroad.Researchers in China, Ye Hai etal1 studied the effect of surface load on polluted river water treated by multi-soil-layer system.Song Ying 2had studied the treatment effect of multi medium soil infiltration system for turtle breeding wastewater.Zou Jun 3also pointed out tha

12、t multi-soil-layer material selection will have a certain impact on the domestic sewage treatment efficiency.In foreign countries, especially in Japan, Thailand and Indonesia, MSL systems have been used to handle various types of wastewater, but the domestic of this technology in sewage treatment in

13、 rural areas there is no comprehensive study,This article through to the MSL system technology processing rural domestic sewage research, inorder to provide some technical support for the MSL system in the practical application of rural sewage treatment.2.1characteristics of rural sewageFor a long t

14、ime,China's pollution control on rural attention and investment far less than the city,96% of the villages without drainage pipe network and sewage treatment system,The random discharge of domestic sewage has become one of the main reasons for the deterioration of water quality in the basin, and

15、 is also an important factor causing the rural water environment pollution and lake eutrophication.At the same time, it seriously affects the safety of production and living in the rural areas, and seriously affects the economic development.The main features of rural sewage in China are:(1The amount

16、 is huge and increases year by year.Statistics show that in 2002.There are 3.205 million tons ofnational rural domestic sewage daily emissions.The total nitrogen emission is about 283.1t, total phosphorus daily emission is about 56.6t, basically without any treatment directly discharged.(2Water qual

17、ity and water quantity fluctuation arehuge.Rural sewage water is not stable, different periods have different water quality,generally do not contain heavy metals and toxic and harmful substances, but contains more synthetic detergent and bacteria, viruses.(3More sources.In addition to human feces, k

18、itchen generated sewage, thereare household cleaning, domestic waste landfill leachate generated sewage, which will then enter the river part of the sewage, will cause greater pollution.(4Low treatment rate.Part of the system cannot run low temperature, rural sewage daily variation coefficient and s

19、easonal variation coefficient, the system a few time high load operation, if there is little sewage, it will stop running 4.(5Wide and scattered.Scattered geographical distribution of villages caused sewage dispersion and it is difficult to collect.2.2 the main source of rural sewageRural sewage ref

20、ers to the formation of sewage of the rural areas in the life and production process, including rural production wastewater and rural domestic sewage two aspects.Rural domestic sewage refers to the residents living in the process of toilet discharge of sewage, bath, laundry and kitchen sewage, etc.R

21、ural production sewage refers to livestock and poultry breeding, aquaculture, agricultural products processing and other high concentration of organic wastewater.Because China's rural living is scattered, rural domestic sewage showed a small amount and wide dispersion.Lack of appropriate sewage

22、collection, treatment facilities, domestic sewage without treatment will be free to discharge, the health of rural residents to bring greater harm.At the sametime, rural sewage production also poses a greater threat to the rural ecological environment. 2.3main technologies of decentralized domestic

23、sewage treatment Beginning in 1970s, Japan, the United States, Europe and other developed countries on the use of decentralized sewage treatment of rural sewage treatment, has accumulated a lot of experience, achieved good results.The United States since the mid-20th century began the construction o

24、f rural sewage treatment facilities, in 1972 promulgated the first complete clean water, then according to the distributed processing technology in 2002 promulgated the decentralized sewage treatment system application manual 5 .1987, In Denmark promulgated a 6 decentralizedsewage treatment guidelin

25、es .Germany from 2003 to implement the decentralized needle infrastructure system project research, use membrane bioreactor purification to treat remote rural sewage 7 .Australia proposed a sewage treatment land use system 8 .While research and application of rural sewage decentralized treatment in

26、Chinabegan in late 1980s,Compared with developed countries and regions, there are still many gaps in laws and regulations system, technical standard system and management and service system.In recent years, domestic scholars have done a lot of research on rural domestic sewage,and puts forward some

27、mature processing technology, including aerobic biological treatment, anaerobic biological treatment technology, is in need of such technology, sustainable development can protect the public health and the environment. 4.Reference 1 Ye Hai Ye et al. Effect of surface load on polluted river water tre

28、ated by multi-soillayer systemJ. China water supply and drainage, 2012,28 (19: 74-77 2Ying Song et al.Treatment of turtle aquaculture effluent by an multi-soil-layer systemJ.Journal ofZhejiang University Science B.2015,16(2:145-154 3Zou Jun, Chen Xin et al. Effect of material selection of multi-soil

29、-layer system on domestic wastewater treatment efficiencyJ. Journal of ecology and rural environment, 2010,26 (1: 14-18 4Zhang Keqiang etal. Rural sewage treatment technologyMBeijing: China Agricultural Science and Technology Press, 2006.10 5 Chen Jinmingetal.Policy and experience of managing decent

30、ralized wastewater treatment systems in the United States J. China water supply and drainage, 2004,20 (6: 104-106 6 Hans B.Danish guidelines for small-scale constructed wetland systems for onsite treatmentof domestic sewageC.Proceedingsof the 9th International Conference on Wetland Systemsfor Water Pollution Control,Avignon,France, 2004:1-8