Department of Civil and Environmental Engineering, The University of California, Los Angeles, CA, USA.
Department of Civil and Environmental Engineering, The University of California, Los Angeles, CA, USA.
Water Res. 2021 Feb 15;190:116781. doi: 10.1016/j.watres.2020.116781. Epub 2020 Dec 24.
Eutrophication is caused by excess nitrate and other nutrient exported via stormwater runoff to surface waters, which is projected to increase as a result of climate change. Despite recent increases in the implementation of stormwater control measures (SCM), nutrient export has not abated, indicating poor or inconsistent removal capacities of SCM for nitrate. However, the cause of the variability is unclear. We show that both design and local climate can explain nitrate removal variability by critically analyzing data reported on the international BMP database for nitrate removal by four common types of SCM: bioretention cells, grass swales, media filters, and retention ponds. The relative importance of climate or design on nitrate removal depends on the SCM type. Nitrate removal in grass swales and bioretention systems is more sensitive to local climate than design specifications, whereas nitrate removal in the retention ponds is less sensitive to climate and more sensitive to design features such as vegetation and pond volume. Media filters without amendment have the least capacity compared to other SCM types surveyed, and their removal capacity was independent of the local climate. Adding amendments made up of carbon biomass, iron-based media, or a mixture of these amendments can significantly improve nitrate removal. The type of carbon biomass is also a factor since biochar does not appear to affect nitrate removal. This analysis can help inform the selection of SCM and modification of their design based on local and projected climate to maximize nitrate removal and minimize eutrophication.
富营养化是由通过雨水径流输出的过量硝酸盐和其他营养物质引起的，预计随着气候变化，这种情况将会增加。尽管最近增加了雨水控制措施（SCM）的实施，但营养物质的输出并没有减少，这表明 SCM 对硝酸盐的去除能力较差或不一致。然而，造成这种可变性的原因尚不清楚。我们通过对国际 BMP 数据库中报告的四种常见类型的 SCM（生物滞留池、草沟、介质过滤器和滞留池）去除硝酸盐的数据进行批判性分析，表明设计和当地气候都可以解释硝酸盐去除的可变性。气候或设计对硝酸盐去除的相对重要性取决于 SCM 类型。草沟和生物滞留系统中的硝酸盐去除对当地气候比设计规范更敏感，而滞留池中的硝酸盐去除对气候的敏感性较低，对植被和池塘体积等设计特征的敏感性较高。没有添加改良剂的介质过滤器与调查的其他 SCM 类型相比，去除能力最低，其去除能力与当地气候无关。添加由碳生物质、基于铁的介质或这些改良剂的混合物组成的改良剂可以显著提高硝酸盐的去除率。碳生物质的类型也是一个因素，因为生物炭似乎不会影响硝酸盐的去除。这种分析可以帮助根据当地和预计的气候选择 SCM 并修改其设计，以最大限度地去除硝酸盐并最小化富营养化。
