基于地表水环境容量的湖南工业废水铊污染物排放控制研究

Research on Discharge Control of Thallium Pollutants from Hunan Industrial Wastewater Based on the Environmental Capacity of Surface Water

根据水环境功能区划中流域水控制单元的划分和相应的水质保护目标,调查了湖南省湘、资、沅、澧四大流域工业用水功能区各控制单元相应集水区内的典型涉铊污染源,统计各控制单元含铊工业废水入河量。选择模型计算各控制单元铊污染物水环境容量。按照容量总量管理兼顾目标总量管理的模式,提出各控制单元铊污染物排放的总量控制方案,计算该总量控制方案下工业废水铊污染物的最大允许排放量。湖南省四大水系中,铊污染物最大允许排放量的最低值出现在湘江长沙段,代码为湘长-033至湘长-038的控制单元,铊污染物最大允许排放量为0.0002 mg·L^−1;最高值出现在湘潭的湘江涓水,代码为湘湘118的控制单元,铊污染物最大允许排放量为0.98 mg·L^−1。按照“功能分区、污染物分类、标准分级、生产分期”的原则,在经济、技术合理并确保90%以上的控制单元满足地表水环境容量的前提下,通过水质模型建立水环境容量和废水排放量之间的换算关系,反向推算到工业企业铊污染物的排放控制要求。综合考虑人体健康、生态安全、水质达标等多个方面,厘定0.005 mg·L^−1为工业废水铊污染物排放标准,对工业废水铊污染物的直接排放和间接排放实行控制,从而实现水环境的目标管理。通过与国内外同类标准的比较与分析,评估了该标准约束下,当地的环境与经济效益。可判断,这种基于地表水环境容量且兼顾目标总量管理的铊污染物排放标准的厘定方法是科学的、合理的。

According to the division of the basin water control units in the water environment function zoning and the corresponding water quality protection goals,the typical thallium-related pollution sources in the corresponding catchment areas of each control unit of the industrial water functional zones in the four major river basins of Hunan Province,Xiang,Zi,Yuan,and Li were investigated,and the amount of industrial wastewater containing thallium in each control unit was counted.A model to calculate the water environmental capacity of thallium pollutants in each control unit was selected.According to a model of total capacity management,in combination of target capacity,a total control plan for thallium pollutant discharge from each control unit is proposed,and the maximum allowable discharge of thallium pollutants from industrial wastewater under the total control plan is calculated.Among the four major water systems,the lowest value of the maximum allowable discharge of thallium pollutant is 0.0002 mg·L^−1,appearing in the control units of the Changsha section of Xiangjiang River,coded from Xiang-Chang-033 to Xiang-Chang-038.The highest permissible discharge amount is 0.98 mg·L^−1,appearing in the control unit of the Xiangtan section of Juanshui in Xiangjiang River coded by Xiang-Xiang-118.According to the principle of“functional zoning,pollutant classification,standard classification,and production staging”,under the premise of economic and technological rationality and ensuring that more than 90%of the control units meet the surface water environmental capacity,the conversion relationship between water environmental capacity and wastewater discharge volume is established through the water quality model.The discharge control requirements of thallium pollutants of industrial enterprises can be calculated.Taking human health,ecological safety,water quality standard and other aspects into consideration,0.005 mg·L^−1 is proposed as the discharge standard of thallium pollutants in industrial wastewater and control the direct and indirect discharge of thallium pollutants in industrial wastewater to achieve the target management of water environment.Through comparison and analysis with similar standards domestically and abroad,the local environmental and economic benefits under the constraints of this standard are evaluated.It can be judged that this method is scientific and reasonable by determining the discharge standard of thallium pollutants based on the environmental capacity of the surface water and consideration of the management of the target total amount.