金泽水源地径流污染源头控制技术应用

Application of Surface Runoff Pollution Control in Jinze Water Source

通过小试与现场应用试验研究适合高地下水位地区需求的不透型径流源头控制技术,包括强化除磷与蒸发的渗透铺装与强化脱氮与除磷的干植草沟技术。前者通过在不透型渗透铺装的碎石基层中设置吸水毛细柱,强化对基层饱水区中水分的蒸发,达到削减不透型设施的径流水量以及缓解城市热岛效应的效果。通过现场试验,证明新型渗透铺装的径流总量削减率超过90%,午后阳光下设施表面的温度最高可降低15.3℃;新型渗透铺装对径流中TP的年污染负荷控制率达到84.7%。干植草沟基质层添加3%~5%(w/w)的发酵木屑后,进水期基质中有机质降解耗氧形成了缺氧环境,在基质层厚度为30 cm、服务面积比为10%的设计条件下,现场试验实现了进水期反硝化脱氮;在植草沟基质中添加10%(w/w)给水厂污泥强化了设施的除磷效果,监测期内设施对径流TP、TN的浓度去除率分别达84.8%和40.9%,2019年汛期设施对TSS、COD、TP、TN、NH4+-N的质量负荷削减率分别为95.4%、83.1%、90.0%、57.7%、78.3%。研究成果为高地下水位、高污染控制目标的金泽水源地的径流源头控制提供了工程技术支撑。

To meet the requirement of surface runoff control in high ground water table area,two kinds of impermeable runoff source control techniques were studies through bench&pilot scale experiments:namely innovative permeable pavement enhancing evaporation and phosphorus removal,and dry grass swale enhancing removal of nitrogen and phosphorus.The former technique improving evaporation of a bottom lined permeable pavement with capillary columns which was vertically inserted in gravel of the base course,and then the device’s annual runoff control rate was dramatically improved and surface temperature of the pavement in summer was lowered,which is beneficial to relieve heat island of a city.In situ experiment showed that the annual runoff control rate of the innovative permeable pavement exceeded 90%and highest surface temperature reduction in summer noon reached 15.3℃.Annual pollution load removal rate of phosphorus of the device arrived 84.7%.While three to five percent(w/w)of fermented wood chips were added in the substrate of the dry grass swale,anoxic atmosphere was formed during the influent period and denitrification happened for organics biodegradation exhausted DO in inflow water,in the condition of the depth of substrate was 30cm,and area ratio of device to catchment was 10%,the in situ device performed well under real rainfall events,and influent TN concentration removal of the monitoring period(from April 1 to August 31,2019)in average was 40.9%.Residuals of drinking water treatment plant was used as amendment of the substrate(10%w/w)of the swale to enhancing TP removal,then influent TP concentration removal in average reached 84.8%.During the rain-season of 2019,pollutant mass load removal of the swale for TSS、COD、TP、TN、NH+4-N reached 95.4%、83.1%、90.0%、57.7%、78.3%,respectively.The results provide support for runoff source pollution control for the area where groundwater table is high and nonpoint source pollution control is important.