天津滨海临港工业园区径流污染特征及其控制策略

控制工业园区面源污染是解决天津滨海新区日益突出的水环境问题和维持周边海域水生态安全的关键。为缓解该区域日益突出的生态环境恶化与经济可持续发展的矛盾，以天津滨海新区临港工业园区1期建设产业园区丰水期的5场典型降雨径流为研究对象，通过多次降雨事件的平均浓度(EMCs)分析了工业园区不同下垫面的径流污染中氨氮(NH₃-N)、总氮(TN)、活性磷(SRP)、总磷(TP)、化学需氧量(COD)、总悬浮物(TSS)及6种溶解性重金属铜(Cu)、铅(Pb)、锌(Zn)、铬(Cr)、镉(Cd)、镍(Ni)污染程度。结果表明，天津临港工业园区径流污染中COD、NH₃-N、TN在屋面径流雨水中较为突出，COD(EMCs=170.68 mg·L⁻¹)、氨氮(EMCs=14.49 mg·L⁻¹)和TN(EMCs=29.66 mg·L⁻¹)含量分别是地面径流雨水中EMCs含量的1.4、3.33和1.64倍；地面径流雨水中SRP(EMCs=1.87 mg·L⁻¹)和TSS(EMCs=163.18 mg·L⁻¹)含量分别为屋面径流雨水的2.26倍和2.87倍，TP含量(EMCs=1.43 mg·L⁻¹)在屋面径流雨水和地面径流雨水中含量相当；6种毒性重金属污染程度相对较轻，与天津主城区相当，比较突出的Cr、Zn、Cu 3种元素含量在临港工业园区径流污染中依然具有潜在的生态环境风险。以径流污染输出负荷同径流量关系的M(V)曲线为基础，通过污染物初始冲刷比率(M_FFRn)及冲刷强度系数b对不同下垫面径流污染物输移过程进行量化分析。结果表明，总体上，累积径流量的前20%能发生较为显著的初始冲刷效应(M_FFR20比M_FFR30高出10%)，且出现初始冲刷现象(b<1.025)的概率约为75%，降雨强度及下垫面累积污染负荷会对次降雨径流污染输移曲线产生较大影响。结合污染物来源解析可知，源头控制、过程清洁及初期雨水截流是缓解当前工业园区径流污染的有效策略。

Pollution characteristics and control strategies of runoff in Tianjin Binhai Lingang industrial park

Controlling non-point source pollution in industrial parks is the key to solve the increasingly prominent water environment problems in Tianjin Binhai New Area and to maintain the water ecological security in the surrounding sea areas. In order to alleviate the increasingly prominent contradiction between the deterioration of ecological environment and sustainable economic development in the region, five typical rainfall runoffs during the flood season of Lingang Industrial Park Phase 1 construction in Tianjin Binhai New Area were taken as the research object in this study. The average concentrations of multiple rainfall events (EMCs) were used to analyze the pollution levels of Ammonia Nitrogen (NH3-N), Total Nitrogen (TN), Soluble Reactive Phosphorus (SRP), Total Phosphorus (TP), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS) and six soluble heavy metals Cu, Pb, Zn, Cr, Cd, Ni in the runoff pollution of different underlying surfaces in the industrial park. The results showed that COD, NH3-N and TN in runoff pollution in Tianjin Lingang Industrial Park were more prominent in roof runoff rainwater, and the contents of COD (EMCs=170.68 mg·L−1), ammonia nitrogen (EMCs=14.49 mg·L−1) and TN (EMCs=29.66 mg·L−1) were 1.4, 3.33 and 1.64 times of those in surface runoff rainwater, respectively. The contents of SRP (EMCs=1.87 mg·L−1) and TSS (EMCs=163.18 mg·L−1) in surface runoff rainwater were 2.26 and 2.87 times of those in roof runoff rainwater, respectively, and the TP content (EMCs=1.43 mg·L−1) was equivalent between roof runoff rainwater and surface runoff rainwater. The pollution degree of six toxic heavy metals was relatively light, which was equivalent to the main urban area of Tianjin. The prominent contents of Cr, Zn and Cu still had potential ecological and environmental risks in runoff pollution in Lingang Industrial Park. Based on the M(V) curve of the relationship between runoff pollution output load and runoff, the pollutant transport process of runoff on different underlying surfaces was quantitatively analyzed through the pollutant first scour ratio (MFFRn) and scour intensity coefficient b. The results showed that, in general, the first 20% of accumulated runoff was more prone to the first scouring effect (MFFR20 is 10% higher than MFFR30) than the first 30% of accumulated runoff, and the probability of the first scouring phenomenon (b<1.025) was about 75%. Rainfall intensity and the accumulated pollution load on the underlying surface had a great impact on the pollution transport curve of the secondary rainfall runoff. Combined with the analysis of pollutant sources, source control, process cleaning and initial rainwater interception will be effective strategies to alleviate runoff pollution in the current industrial park.