Study On Verification Technology Of Emission Limits Based On Water Quality Target

It has become an important measures to improve the improvement of water quality in the river basin to strengthen the management of pollutant discharge and implement stricter limit of pollutant discharge permit.During the 14th Five-Year Plan period,the management of pollutant discharge permit in China will gradually transition to the management stage of focusing on water quality target management stage.In order to adapt to the new management requirements of pollutant discharge permit in China,The research on the calculation method of emission limits based on water quality was carried out,and an case study was carried out in Zhengzhou section of Jialu River Basin.The main conclusions are as follows:(1)Aiming at the problem that the current method of setting the limit of emission has little relation with water quality,through the applicability analysis of the existing accounting methods,this paper puts forward a method of pollutant discharge permit quantity calculation based on multi-level response relationship and a method of pollutant discharge permit concentration verification based on water quality inversion,which takes the discharge outlet on the rivers as the core.On the basis of improving the calculation method of pollutant discharge permit limit,formulate the technical process of emission limits verification based on water quality,including identification of factors exceeding watershed standards,analysis of pollution emission structure,multi-level response relation construction,emission permit limit verification.(2)In this paper,the construction method of multi-level response relation of"pollution source-discharge outlet-water body section" is studied,and the multi-level response relation is constituted of the water quality response relation between the discharge outlet and section,and the source-sink relation between pollution source-discharge outlet and river section.The applicability of the construction method of water quality response relationship was analyzed,and a mechanism model was proposed to determine the response relationship between the discharge outlet and the receiving water body section,and the distribution coefficient method considering the distance and discharge level was proposed to quantify the source-sink relationship between the pollution source and the discharge outlet.(3)An empirical study was carried out in Zhengzhou section of Jialu River Basin.and it was determined that the over-standard factor in Zhengzhou section of Jialu River Basin was COD,and point source pollution was the main source of pollution.Calculate emission limits based on water quality,in terms of the total amount of pollutant discharge permits,the total amount of pollutant discharge permits of fixed pollution sources based on water quality is 6897.31 t/a,which is 2033.28 t/a less than the current emission,and 7770.6 t/a less than the total amount of pollutant discharge permits based on technology.Contrast tradable permits concentration limit,based on the water quality pollution permits concentration limit is lower than the river discharge standard concentration,compared concentration limit based on technology,based on the water quality of tradable permits concentration limit in guarantee meet emission standards in at the same time,considering the reduction ability of different units,and based on the concentration limit of technology,is determined according to the river discharge standards,lack of respect for differences between units.By comprehensively comparing the total amount of pollutant discharge permits and the concentration of pollutant discharge permits,the limit of emission permits based on water quality is more restrictive to the pollutant discharge behavior than the limit of emission permits based on technology,which is more conducive to improving the quality of water environment.