The Emission Characteristics Of Domestic Sewage From Urban Residents In The Shiwuli River Basin

With the increasing number of urban population and towns,the discharge of domestic sewage is also increased.By 2015,the urban domestic sewage has reached 72.8%of the total amount of waste water discharged from the country and the amount of chemical oxygen demand and ammonia nitrogen in domestic wastewater is also much higher than that of industrial emissions.Domestic sewage contains large amounts of nitrogen,phosphorus and other nutrients,are the main factors causing eutrophication of water bodies,especially for urban lakes which are affected by human activities.It leads to the frequent occurrence of cyanobacteria and water bloom,and even endangers the safety of drinking water and the social and economic development.Therefore,the key control of municipal sewage can effectively improve the surface water and water environment.In this study,the research object is the living source of urban residential district in the Shiwuli River basin.On the basis of on-site sampling and monitoring,the pollution load of living sources of urban residents in the Shiwuli River Basin in 2016 was calculated,and the temporal and spatial characteristics of sewage discharge from urban residents were analyzed.The results were shown as follows:(1)In 2016,the Shiwuli River basin domestic sewage emissions in urban area was 19.73 million tons.In terms of time features,from the perspective of seasonal change,wastewater emissions present law of summer>autumn>spring>winter.From the perspective of monthly change,sewage emissions have risen slowly from January to the highest in August,up to 1.93 million tons,and then gradually declined.From the angle of daily change,the sewage discharge of Urban Residential District reached its peak in September 9th to 65000 tons.In terms of spatial characteristics,most of the sewage discharged in the watershed is mainly distributed in the Zhengwu District and the Shushan District,and the distribution of the drainage households is similar to the distribution of the high-grade residential areas,which is more concentrated in the Zhengwu District.From the discharge of sewage District perspective,wastewater emissions present law of Baohe District>Zhengwu District>Shushan district>Gaoxin district>Jingkai district>Binhu district.(2)In 2016,the emission of COD,NH4+-N,TP and TN in the urban residential areas of the Shiwuli River Basin were 4184.4 tons,834.1 tons,79.6 tons and 1027.6 tons.In terms of time features,the changes of the four kinds of pollutants were similar,showing the rules of autumn>winter>spring>summer,and the highest pollutant load in September.In terms of spatial characteristics,urban residents sewage emissions of each pollutant load is similar,but it is contrary to the distribution of sewage discharge.The large amount of pollutant emissions are mostly mid-range residential,and mainly concentrated in the Baohe district and Shushan district.From the emission of pollutants in each area,the emission of COD,NH4+-N,TP and TN show Baohe District>Shushan district>Zhengwu District>Gaoxin district>Jingkai district>Binhu district.From the perspective of pollution sources,four kinds of pollutant source strength distribution present law of Shushan district>Jingkai district>Zhengwu District>Gaoxin district>Baohe District>Binhu district.(3)Life style,Income level,age structure,family size,educational level snd environmental consciousness has higher correlation to the average pollutant emission amount of residents.Among them,the lifestyle and income are the main factors affecting the emission of pollutants.Compared with the emission of pollutants at the middle level,the less pollutants produced in the lifestyle of residents,the higher awareness of environmental protection,the smaller family size,the higher cultural degree,while the average pollutant emissions is low.The more pollutants produced in the lifestyle,the lower educational level,the more elderly in the family,the income level is more than 10 thousand yuan are more likely to have a high level of pollutant discharge.Based on the above analysis,this study put forward the following suggestions from the angle of emission reduction and pollution control:(1)implementing ladder water price,restricting the water consumption of residents by price mechanism,advocating water conservation,encouraging residents to make rational use of water resources,and actively protecting water resources.(2)Strengthening the collection and disposal of domestic sewage and to strengthening the verification and rectification of sewage pipe network focused on the area of the key areas of Baohe district and Shushan district.(3)Establishing and improving the information sharing platform for the basin data,and strengthening the communication and information sharing of the public.(4)Establishing and improving the emergency mechanism for emergency accidents,improving the rapid response and emergency handling capacity of the relevant government departments,and prevent the emergency of river water pollution.