Pollutant removal performance of field scale dual-mode biofilters for stormwater, greywater, and groundwater treatment

• DOI: 10.1016/j.ecoleng.2021.106192
• Publication Date: 2021-03-06T02:07:00Z
• Authors: Kefeng Zhang; Natalie J. Barron; Yaron Zinger; Belinda Hatt; Veljko Prodanovic; Ana Deletic
• Keywords: Greywater; Biofilter; Bioretention

Abstract To extend the application of stormwater biofilters (known also as bioretention systems or raingarden) under varied climate conditions, the concept of dual-mode biofilters (i.e., a biofilter that treats two sources of water) has recently emerged. However, studies of these systems have been limited to the laboratory-scale, and validation of the new concept at the field-scale is paramount. This paper presents results from the first field study on two full-scale dual-mode biofilters that operate under different climate conditions and operational regimes. The first, a dual-mode stormwater-greywater biofilter located in Jurong, China, received stormwater and greywater in various combinations. The second, a dual-mode stormwater-groundwater biofilter in Kfar-Sava, Israel, treats stormwater in the wet season and contaminated groundwater in the dry season. It was observed that the stormwater-greywater (Jurong) biofilter was able to provide effective treatment for the majority of pollutants regardless of time of the year, water source, or operational mode (stormwater-only, greywater-only or mixed). Higher levels of greywater nitrogen (total nitrogen ~5.5 mg/L, about two times that in local stormwater) and carbon (e.g., BOD5 110 mg/L about ten times that in stormwater) were also found to positively impact nitrogen removal. The stormwater-groundwater (Kfar-Sava) biofilter was able to effectively treat stormwater, with up to 73% removal of total nitrogen, however, when groundwater containing high levels of nitrate (up to 150 mg/L, compared to