生物滞留系统设置内部淹没区对径流污染物去除的影响

生物滞留系统是一种能有效控制雨水径流污染的低影响开发技术。在基质中添加铝污泥能保证系统对磷的高效稳定去除,设置内部淹没区可以提高除氮能力,但有研究表明设置淹没区却降低了对磷的滞留效果。为了明确设置淹没区对铝污泥改良基质生物滞留系统去除污染物的影响,采用按一定质量比例配制的砂土铝污泥(15%铝污泥+85%砂土)作为滞留系统填料,并设置不同淹没高度和滞留时间的淹没区,对比污染物在无淹没区及不同淹没高度和滞留时间下的去除率。结果显示,在铝污泥改良基质生物滞留系统中,淹没区的设置对NH+4-N、TP、重金属的去除影响甚微,但能提高对COD和NO-3-N的去除。600 mm淹没高度下NO-3-N的去除效果较200 mm淹没高度下去除效果更加稳定且高效,滞留时间对COD、NO-3-N的去除影响较小。

IMPACT OF A SUBMERGED ZONE ON POLLUTANTS REMOVAL IN WTR-MODIFIED BIORETENTION

Bioretention is an effective treatment option for the pollutants loads in urban stormwater.The introduction of a submerged zone (SZ) and aluminum-based water treatment residuals (AWTRs) as media amendment have been shown to enhance nitrogen and phosphorus removal respectively.However,some research found the phosphorus removal with the introduction of SZ was deteriorated.Aiming to examine the impact of a submerged zone on pollutants removal in bioretention modified with AWTR,a laboratory study using bioretention with different heights of SZ and with AWTRs as media amendment was conducted to compare the removal of pollutants at different levels of SZ and hydraulic retention times (HRT).The results showed that SZ has a slight impact on NH4+-N 、TP and heavy metal removal,but the SZ has a beneficial improvement on COD and NO3--N removal.The height of SZ significantly influences the control of COD and NO3--N than HRTs.