摘要
为考察降雨过程对径流发生的影响及其对多塘湿地进出水水质、水量的影响,基于2017年8月25日和9月6日两次降雨过程中湿地进出水水质水量长时间的变化特征,探究降雨过程中湿地水质水量变化及污染物净化特征.结果表明:(1)多塘湿地进水量峰值出现的时间滞后于降雨雨强峰值及累计雨量峰值.降雨雨强对湿地进水量影响不显著,而累计雨量影响径流的产生量,进而影响湿地进水量,造成湿地水力负荷急剧上升,最高达2.45 m^(3)/(m^(2)·d).降雨过程中多塘湿地水位上升,水深加深,有效容积增大,水力停留时间延长.(2)进水水质变化随降雨过程无显著规律,但进水污染物负荷量始终大于非降雨期,说明降雨期间径流污染仅采用污染物浓度洪峰控制是不充分的,特别是雨季降雨频繁的地区,应重视污染负荷对多塘湿地净化效能的影响.(3)降雨期间多塘湿地对径流污染有良好的截留作用,TN、TP去除率分别为33.6%~88.7%和25.2%~78.0%.研究显示,进水水力负荷的增加增强了湿地的扰动,导致部分单元污染物出口浓度高于进水,但由于调蓄塘-表流湿地-塘-生态浮床-稳定塘耦合工艺的梯级单元有助于湿地系统对污染物消纳截留,增强了湿地对降雨径流的截留稳定性.
In order to investigate the impact of rainfall events on the occurrence of runoff and the water quality and quantity of the influent and effluent in the multi-pond constructed wetland,the characteristics of water quality and quantity during the two rainfall events on August 25th and September 6th in 2017 were analyzed to explore the changes of water quality,water quantity and the purification performance.The results showed that:(1)The peak time of water inflow in the multi-pond constructed wetland lagged behind the peak of the rainfall and the turning point of the cumulative rainfall.The rain intensity had no significant effect on the water quantity of influent water of the multi-pond constructed wetland,while the cumulative rainfall affected the amount of runoff,and then significantly affected the amount of water inflow,resulting in a sharp increase in the hydraulic load rate with a maximum value of 2.45 m^(3)/(m^(2)·d).During the rain events,the rising water level in the multi-pond constructed wetland increased water depth and effective volume,the hydraulic residence time were approximately prolonged.(2)The characteristics of water quality of the influent water of the multi-pond constructed wetland had no regularity with the rainfall,but the pollutant mass loads of the influent were always greater than those during the non-rainfall period.This indicated that only using the peak control of concentration for the treatment of runoff pollution during the rainfall period was not sufficient,especially in areas with frequent rainfall during the rainy season.More attention should be paid to the impact of pollution load on the purification performance. (3) During the rainfall period, the multi-pond constructed wetland had a good interception performance on runoff pollution, and the removal efficiencies of TN and TP were in the range of 33.6%-88.7% and 25.2%-78.0%, respectively. The increase of hydraulic load rate in the influent increased the disturbance, resulting in higher pollutant concentrations of the effluent than influent pollutant concentrations in some units. However, the subsequent cascade units in the multi-pond constructed wetland composed of storage ponds, surface flow wetlands, ponds, ecological floating bed and stabilization pond contributed to the interception of pollutants and enhanced the impact resistance to rainfall runoff and the stability of purification performance of multi-pond constructed wetland.
作者
李丹
郑丙辉
储昭升
侯泽英
袁静
LI Dan;ZHENG Binghui;CHU Zhaosheng;HOU Zeying;YUAN Jing(National Engineering Laboratory for Lake Pollution Control and Ecological Restoration,Chinese Research Academy of Environmental Sciences,Beijing 100012,China;State Environmental Protection Key Laboratory of Lake Pollution Control,Chinese Research Academy of Environmental Sciences,Beijing 100012,China;College of Urban Construction,Nanjing Tech University,Nanjing,211816,China)
出处
《环境科学研究》
CAS
CSCD
北大核心
2022年第7期1605-1614,共10页
Research of Environmental Sciences
基金
云南省科技厅科技计划项目(No.2018BC001)
国家水体污染控制与治理科技重大专项(No.2017ZX07401003)。
关键词
多塘湿地
降雨径流
污染物截留
水力负荷
水力停留时间
梯级单元
multi-pond constructed wetland
storm runoff
pollutant interception
hydraulic load rate
hydraulic residence time
cascade units
