南太湖地区农村小流域非点源污染调控研究

Non-point Pollution Control of Rural Watersheds in South Taihu Lake Basin

随着农村非点源污染问题的日益突出,将总量控制体系纳入到非点源污染的防治中已具有重要的作用和意义。许多研究都对减少农村非点源污染提出了一些政策性建议和工程性措施,但对于农村非点源污染物排放量的具体调控研究较少,没有按照"公平、效率、可行"的原则进行污染物总量的分配。基于对南太湖地区农村小流域典型污染物输出特征的研究,本文利用排污系数法对农村非点源污染物排放量进行了快速估算,采用最大纳污量优化程序计算了农村小流域内水体纳污量与环境容量,并提出相应的污染物削减对策。研究结果表明:南太湖地区农村小流域污染物输出主要超标因子为总磷,农村生活污染为主要污染源。流域污染物输出浓度受季节变化影响较大,提高水体自净能力能够有效缓解夏季污染物对水质的影响。此外,依据BAT体系建立的最大排污量优化计算方法可以快速有效的制定出农村小流域非点源污染控制方案。

Agricultural non-point source pollution has become increasingly serious due to the development of agriculture during recent years.A multitude of investigations have revealed that non-point source pollution from agriculture and rural regions is the leading source of water pollution in the Taihu Lake basin.In order to control agricultural non-point source pollution and improve water quality,many policies and measures have been formulated and developed.Previous studies stated that the total emission control appears to be effective in abating agricultural non-point source pollution.However,specific measures of effective control of pollutants of the non-point source pollution over rural areas seem to be inadequate,without adhering to the principles of equity,efficiency,and feasibility to reasonably allocate the quotient of the total pollution control to each stakeholder within a rural watershed.The authors investigated the non-point source pollution in the Taihu Lake Basin ranging in elevation between 1.86 m and 2.02 m above the sea level.Rainy season for the basin is generally during the months from April to September,with showing a mean annual rainfall of roughly 1275 mm.An experiment was carried out in April,July,and December in 2007,collecting water samples from the surface runoff in three lakes.The water samples were stored in a cold room and were then equilibrated at the room temperature before analysis.Based on typical output pollutant characteristics of rural watersheds in the Southern Taihu Lake areas,we used the optimized maximum quantity of a pollutant program to calculate the maximum capacity of the water in the rural watershed to retain pollutants and the environmental capacity,and proposed appropriate measures aimed at reducing pollutants.Results showed that the total phosphorus was the major component exceeding its permitted level in pollutants of rural watersheds in South Taihu Lake.The main sources of pollution were rural domestic pollution.Concentrations of agricultural non-point source pollutants were affected by seasonal changes in watershed and environmental factors.Improved water self-purification capacity could effectively mitigate the impact of pollutants on water quality in summer.In addition,the maximum emission calculation method could efficiently optimize the formulation of a rural watershed non-point source pollution control program,which was established by the BAT system.