ARTICLE | doi:10.20944/preprints201810.0007.v1
Subject: Engineering, Other Keywords: benzotriazole; biofilter; bioretention; green infrastructure; phytoremediation; sorption; stormwater
Online: 1 October 2018 (11:55:42 CEST)
Urban stormwater runoff is a significant source of pollutants into surface water bodies. One such pollutant, 1H-benzotriazole, is a persistent, recalcitrant trace organic contaminant commonly used as a corrosion inhibitor in airplane deicing processes, automobile liquids, and engine coolants. This study explored the removal of 1H-benzotriazole from stormwater using bench-scale biofilter mesocosms planted with California native sedge, Carex praegracilis, over a series of three storm events and monitoring period. Benzotriazole metabolites glycosylated benzotriazole and benzotriazole alanine were detected and benzotriazole and glycosylated benzotriazole partitioning in the system were quantified. With a treatment length of seven days, 97.1% of benzotriazole was removed from stormwater effluent from vegetated biofilter mesocosms. Significant concentrations of benzotriazole and glycosylated benzotriazole were observed in the C. praegracilis leaf and root tissue. Additionally, a significant missing sink of benzotriazole developed in the vegetated biofilter mesocosms. This study suggests that vegetation may increase the operating lifespan of bioretention basins by enhancing degradation of dissolved trace organic contaminants, thus increasing the sorption capacity of the geomedia.
ARTICLE | doi:10.20944/preprints201803.0181.v1
Subject: Engineering, Other Keywords: stormwater; biofilter; de-icing chemicals; nutrients; filtration performance
Online: 20 March 2018 (16:28:04 CET)
Biofilter application for treatment of stormwater containing de-icing chemicals commonly applied in airports, propylene glycol and potassium formate, was investigated. Lab-scale adsorption tests using filter media made of crushed clay (Filtralite) and granular activated carbon showed that adsorption was unsuitable for removal of propylene glycol and potassium formate. Column filtration experiment testing two different crushed clay size ranges was conducted. The results showed that DOC removal was dependent on a number of factors. This study investigated the impact of filter depth, nutrients addition, and filtration rate. DOC removal suggested that DOC degradation occurred on the top filter layer. It was shown that the most active separation occurred in the first ~20 cm of filter depth. This was confirmed by results from water quality analysis (i.e. DOC removal and ATP measurement) and calculations based on a filtration performance analysis (Iwasaki model) and filter hydraulic evaluation (Lindquist diagram). It was shown that for the highest C:N:P ratio tested (molar ratio of 24:7:1), 50-60% DOC removal was achieved. Addition of nutrients was found important and determining the biofilter performance.