Analysis Of The Current Situation Of River Pollution In Arid And Semi Arid Region Countermeasures

Since twentieth Century,it has been an important period for the rapid and comprehensive development of human society.The influence of human production and living activities on the rivers in the natural environment is more obvious[1].Especially in the last half century,the frequency of environmental pollution induced by water pollution,soil pollution and so on is rising in a straight line,which makes it urgent to realize its management and ecological restoration.The current situation of water pollution control at home and abroad is very severe.The state,society,government and related researchers have invested a large amount of funds,technology and manpower and material resources to control the river.The Niugu River in Dingxi is located in arid and semi-arid area of Northwest China.The drought is less than the rainfall,the annual average precipitation is less than evaporation.The population of Tongwei county is mostly concentrated on the river coast.The influence of production and living activities aggravates the pollution of the river river and becomes the inferior V water,which is a serious pollution state.Through the analysis of the pollution status and spatial and temporal distribution characteristics of the Niugu River Basin in Tongwei County,the pollution index analysis of the river sediment,the calculation of the pollution sources in the river and the cause of pollution,the following conclusions are drawn.(1)The water pollution level gradually increased in the cattle valley river from 2012 to 2016,and the main pollution indexes in the water body were total nitrogen,ammonia nitrogen and organic matter.Pollution level county section>downstream>upstream.The pollution levels were less than 1,2 and 4 in the third quarter of the year.(2)The main sources of pollution in the Niugu river basin are industrial,urban residents' domestic sewage,rural residents' domestic sewage,residents' domestic waste,livestock and poultry pollution,farmland source and soil erosion.The amount of pollution load produced in the river basin in 2016 was COD 12210.38t/a,TN 1355.82t/a,TP 138.03t/a,and ammonia nitrogen 742.73t/a,and the emission of pollution load was COD 4008.37t/a,TN 857.59t/a,TP,ammonia and nitrogen.The main sources of pollutants in the basin are urban domestic sewage,livestock and poultry farming and rural domestic sewage,accounting for more than 80%.Among the sources of COD pollution,the proportion is 47%,23%and 16%respectively.The proportion of TN pollution sources is 40%,25%and 15%respectively.Among the sources of TP pollution,the proportion is 44%,14%and 15%respectively.The proportion of ammonia nitrogen pollution sources is 59%,19%and 18%respectively.From the perspective of the types of pollution sources in the river,the sources of pollutants in the river valley are mainly urban domestic sewage,livestock and poultry farming and rural domestic sewage,accounting for more than 80%.Among the sources of COD pollution,the proportion is 48%,27%and 14%respectively.The proportion of TN pollution sources is 42%,30%and 14%respectively.Among the sources of TP pollution,the proportion is 50%,17%and 15%respectively.The proportion of ammonia nitrogen pollution sources is 60%,20%and 15%respectively.(3)Governance proposals should adhere to the principle of zoning and take water quality restoration as the fundamental purpose.Based on the pollution source control of county and township,water quality purification and ecological restoration are the core,water conservation and water supply are the foundation,management monitoring is the guarantee measure,and the overall management of river basin is the general idea.