Controlling Stormwater Quality with Filter Soil—Event and Dry Weather Testing

Abstract

Abstract:The use of filter soil is increasing for control of quality of stormwater runoff prior to infiltration or discharge. This study aimed to gain knowledge about treatment efficacy of filter soils at field scale. Percolate samples from swale-trench systems with filter soil based on agricultural till with/without limestone were monitored for 15 and 9 rain events respectively. Further, two curb extensions with filter soil based on landfill soil were monitored for 10 and 8 events. Pollutant concentrations in percolate were compared to influent samples from the catchment area. Additionally one of the curb extensions was tested twice by adding high-dose synthetic influent containing runoff pollutants of concern. Despite generally low influent pollutant levels, phosphorus, copper, zinc, lead and some polyaromatic hydrocarbons exceeded guiding criteria for protection of groundwater and freshwater. Concentrations in the percolate were in most cases reduced, but phosphorus increased and despite reduced concentrations copper, lead and benzo(a)pyrene still exceeded guiding criteria. Pollutants from the synthetic influent were efficiently retained, except the pesticide MCPA. Filter soil based on landfill soil tended to perform better than agricultural till. No impact of limestone was observed. Overall the filter soils performed well in retaining pollutants, despite simultaneous processes of mobilization and immobilization.

Selective removal of heavy metal ions by disulfide linked polymer networks

“…Among the sources of heavy metal contamination in surface water, stormwater runoff is of increasing interest to environmental engineers and regulators, since other sources have become better managed whereas stormwater runoff treatment is still treated to a limited extent, even though it is considered as wastewater in the EU legislation [6]. The limited extent of stormwater treatment is because runoff mostly occurs from a non-point source, unlike other sources of heavy metals [7].…”

“…However, when AC is applied in water treatment it adsorbs a large variety of mostly non-ionic pollutants and nontoxic solutes, including major cations which compete for the sorption capacity of the material and cause it to become saturated quickly [17] [27]. To overcome this hurdle, various minerals have been studied in passive geo-filters and these have been gradually employed for road runoff in Europe and North America [28] although these filters are only effective for selected pollutants such as lead, zinc, and organic pollutants [6]. Krishnan et al [29] and Young et al [30] previously evaluated the feasibility of a sulfur-crosslinked sorbent for the removal of soft acid metals.…”

Removal of Heavy Metals from Urban Stormwater Runoff Using Bioretention Media Mix

“…The accumulation of suspended solids, heavy metals, hydrocarbons, and other pollutants on these surfaces has also increased [2,3]. Atmospheric pollutants and pollutants dispersed in catchments are accumulated during no-rainfall dry periods, are flushed by rainfall and runoff, and eventually enter the receiving waterbodies, causing serious pollution of the urban water environment [4][5][6][7][8]. At present, China is in a critical period of urbanization, and stormwater runoff pollution has become the second largest source of non-point pollution, second only to agricultural pollution [9].…”

Green Infrastructures in Stormwater Control and Treatment Strategies

“…Furthermore, researchers in Australia [50] investigated stormwater runoff in infiltration trenches and concluded that it's reduction ranged from 5 to 44%, with an average of 18%; moreover, experts in Denmark [51] studied percolate samples from filter soils and established that concentrations in the percolate were in most cases reduced, but phosphorus increased and, despite reduced concentrations, Cu, Pb and benzo(a)pyrene still exceeded guiding criteria for protection of groundwater and freshwater. Scientists in Korea [52] stated that an infiltration trench incorporating physical processes of sedimentation and filtration proved to be efficient in removing dissolved heavy metals from runoff, which attained above 90% for Pb and Zn removal.…”