Improved contaminant removal in vegetated stormwater biofilters amended with biochar. Issue 4 (17th May 2017)

• Record Type: Journal Article
• Authors: Ulrich, Bridget A.; Loehnert, Megan; Higgins, Christopher P.
• Is Part Of: Environmental science. Volume 3:Issue 4(2017)
• Page Start: 726
• Page End: 734
• Publication Date: 2017-05-17
• Subjects: Water-supply -- Periodicals; Water security -- Periodicals; Water resources development -- Periodicals; Water chemistry -- Periodicals; 553.705
• DOI: 10.1039/c7ew00070g
• Languages: English
• ISSNs: 2053-1400

Abstract

Abstract : The potential for carbonaceous sorbents to improve contaminant removal (particularly for trace organic contaminants, TOrCs) in stormwater biofilters was evaluated in intermittently dosed, vegetated columns simulating scaled-down treatment systems. Abstract : The potential for carbonaceous sorbents to improve contaminant removal (particularly for trace organic contaminants, TOrCs) in stormwater biofilters was evaluated in intermittently dosed, vegetated columns simulating scaled-down treatment systems. Columns amended with biochar or granular activated carbon (GAC) were evaluated relative to performance benchmarks set by columns representing unamended treatment systems ( i.e., sand filters and vegetated biofilters). Biochar amendment (6.7 wt%, 33 vol%) strongly improved TOrC removal, despite potential fouling due to the presence of an upper compost-amended layer. Biochar-amended biofilter columns maintained greater than 99% TOrC removal throughout five months of dosing with TOrC-spiked creek water (equivalent to approximately 1.3 years of runoff volume), relative to less than 50% removal of most TOrCs by unamended biofilter columns. GAC amendment (6.7 wt%, 12.5 vol%) also improved TOrC removal, though less effectively than biochar (>70% removal), because the biochar's lower density ( i.e., higher volume composition) and smaller particles improved performance. These results indicate that full-scale biochar-amended biofilters could potentially remove TOrCs effectively for several years, as treatment depths up to five times greater than the 10 cm experimental depth may be feasible for full-scale systems. Further, contaminant removal survey experiments conducted after 6 months of operation revealed that biochar amendment improved removal of total organic carbon, total nitrogen, nitrate, and total dissolved phosphorus in biofilters by greater than 60%. The findings of this study demonstrate the potential of biochar amendment to broadly improve contaminant removal in biofilters, motivating and informing the application of full-scale biochar-amended biofilters for improved water quality.