基于城镇排污视角的水功能区纳污能力模型及其应用

Permissible pollution bearing capacity model of water function zone based on the perspective of municipal wastewater discharge and its application

水功能区纳污能力是区域水功能区限制纳污和责任考核管理的重要依据.为了适应目前以县为主体的水功能区水环境管理方式,本研究从水功能区城镇污染物允许排放量的视角研究水功能区纳污能力,建立水功能区城镇排污模型,并应用于泾河入渭段主要城镇礼泉县和泾阳县.结果表明:礼泉县和泾阳县月允许排污量与河道流量密切相关,丰水期允许排污量高于枯水期.泾河礼泉段当年11月至来年3月水体COD浓度劣于该水功能区水质目标,应削减该时间段礼泉县排污口排污量.排污口排污流量的取值会影响河道水功能区纳污能力的计算结果,城镇排污模型利用相对稳定的排污口排污浓度计算排污口允许排污流量,得到的水功能区纳污能力更为合理.研究结果可为严格的水资源管理提供科学依据.

Permissible pollution bearing capacity was an important basis for the prohibiting pollution discharge and assessing responsibility in the regional water function zone. In order to adapt to the current ‘county-based＇ water environmental management mode in water function zone, we examined the permissible pollution bearing capacity from the perspective of municipal permissible pollution discharge. A municipal pollution discharge model was established to predict the permissible pollution bearing capacity, which was then applied to Liquan and Jingyang counties in the downstream of Jinghe River. The results showed that the permissible pollution discharge in Liquan and Jingyang counties were closely related to the river discharge, with the permissible pollution discharge in the flood season being higher than that in the dry season. The COD concentration in the water function zone of Liquan County exceeded water quality target from November to next March. Therefore, the pollution discharge in this period of Liquan County should be reduced. The value of the pollution discharge would affect the results for the calculation of permissible pollution bearing capacity. The municipal wastewater discharge model could obtain more reasonable results of permissible pollution bearing capacity by using relatively stable pollution concentration data. Overall, our results could provide the scientific basis for the strict system of water resource management.