Research On Simulation Of Contamination Features And Load In Important Buffer Zones Of Provincial Boundary In Lalin River Basin

Water is important resource of human beings. It is an important topic that how to develop, utilize and protect limited water resource scientifically to adapt the development of economy and society. With rapid increase of population and development of economy, the demand of water resource by human beings is also increasing rapidly. During the process of developing and using water resources, the activities of human beings also affect water environment deeply. Regional water environment quality has been damaged, strongly restricting further development of economy and society. The calculation model of contamination load in Lalin River basin is established, the contamination load is calculated quantitatively, and the space-time heterogeneity of basin contamination is analyzed, providing scientific basis for making measures of total quantity control, pollution reduction and the prevention and control of water pollution.Lalin River is a primary tributary of Songhua River at right bank, which is also the boundary river of Heilongjiang Province and Jilin Province. The river flows through Wuchang City, Shuangcheng City, Shangzhi City of Heilongjiang Province, and Shulan City, Yushu City, Fuyu City of Jilin Province. Lalin River basin is an important commodity grain base of China. The grain yield of Yushu City at left bank is the top of China for 8 consecutive years. The Wuchang City at right bank is the township of high quality rice in China, which is famous at home and aboard. In recent years, with the rapid development of urban economy of both banks, Lalin River accepts a large number of industry waste water and irrigation return water, becoming a pollutant discharge channel of the cities along the river, which brings unprecedented pressure to protection of water resources and environment in Lalin River. The trend is existed that the river environment quality is going worse, becoming a serious bottle neck for further development of economy and society in Lalin River basin.In this article, the research areas are the important buffer zones of provincial boundary in Lalin River. Guided by regional actual problems of water environment, grasping the evaluation of regional contamination, using the methods of field investigation and lab analysis, through building the calculation model, the contamination load of point source and non-point source pollution is calculated, and the space-time heterogeneity of basin contamination is analyzed. The research findings can provide strategy basis and scientific instruction for prevention and control of water pollution of important buffer zones of provincial boundary in Lalin River basin. 1. Contamination investigation of Lalin River basinources and non-point sources of pollution are investigated in field. The point sources of pollution investigation include the location, discharge quantity and discharge concentration of important industrial and municipal sewage outlets in 4 important buffer zones of provincial boundary. The non-point sources of pollution investigation include the location, discharge time, discharge quantity and discharge concentration of main outlets of irrigation area. The quantity, distribution and size of uncollected garbage and sandpits along the river are also investigated. 2. Simulation and calculation of contamination load in buffer zones of provincial boundary(1) Calculation of point source contamination loadThrough field monitoring of discharge water quantity and concentration of typical outlets, the contamination load of point sources in the Lalin River buffer zone 2 of Jilin-Heilongjiang is calculated. There exist 14 sewage outlets, discharging COD 6989.62 t and NH3-N 1313.82 t into the Lalin River buffer zone 2 of Jilin-Heilongjiang every year. The COD discharge quantities of Lalin beer factory, Yushu sewage plant, Xinzhan sewage outlet, No.3 drainage canal of Shuangcheng and No.1 outlet of Wuchang Town are relatively large, taking up 70.98% of total quantity. The NH3-N discharge quantities of Lanling outlet in Caijiagou, No.3 drainage canal of Shuangcheng, No.1 outlet of Wuchang Town and Xinzhan sewage outlet are relatively large, taking up 79.69 of total quantity.(2) Calculation of non-point source contamination loadThe output coefficient method is combined with Arcgis. Based on dividing sub water basin, the non-point contamination loads by irrigation sewage are calculated. The total quantity of irrigation sewage is 285.36 million m3/a,the COD load is 11414.49t/a, the TN load is 111.29t/a, and the NH3-N load is 228.29t/a. 3. Up-to-standard evaluation of water quality and analysis of variation trend(1) Up-to-standard evaluation of 4 important buffer zones of provincial boundaryUsing single factor method, the up-to standard situation of water quality in 4 important buffer zones of provincial boundary is evaluated. The water quality of the Lalin River buffer zone 2 of Jilin-Heilongjiang is relatively poor, the water quality of the Lalin River buffer zone 1 of Jilin-Heilongjiang, Xilin River buffer zone of Jilin-Heilongjiang and Mangniu River buffer zone of Jilin-Heilongjiang are relatively good. The exceeding standard factors of Lalin River buffer zone 2 of Jilin-Heilongjiang are NH3-N, COD and TP.(2) Analysis of variation trend of water quality in Lalin River buffer zone 2 of Jilin-Heilongjiang.Based on up-to-standard evaluation, using water quality data from 2007 to 2015, the variation of water quality in flood period, normal period and dry period in Lalin River buffer zone 2 of Jilin-Heilongjiang is analyzed. The contamination of NH3-N in dry period and COD in flood period is serious. 4. Counter measures and suggestionsBased on above research findings, against the contamination properties of point and non-point sources in Lalin River basin, the treatment measures and management counter measures are proposed separately from engineering and non-engineering level.