Iron amendments minimize the first-flush release of pathogens from stormwater biofilters.

Autor: Ghavanloughajar M; Civil and Environmental Engineering, The University of California at Los Angeles, Los Angeles, CA, USA., Borthakur A; Civil and Environmental Engineering, The University of California at Los Angeles, Los Angeles, CA, USA., Valenca R; Civil and Environmental Engineering, The University of California at Los Angeles, Los Angeles, CA, USA., McAdam M; Civil and Environmental Engineering, The University of California at Los Angeles, Los Angeles, CA, USA., Khor CM; Civil and Environmental Engineering, The University of California at Los Angeles, Los Angeles, CA, USA., Dittrich TM; Civil and Environmental Engineering, Wayne State University, Detroit, MI, USA., Stenstrom MK; Civil and Environmental Engineering, The University of California at Los Angeles, Los Angeles, CA, USA., Mohanty SK; Civil and Environmental Engineering, The University of California at Los Angeles, Los Angeles, CA, USA. Electronic address: mohanty@ucla.edu.
Jazyk: angličtina
Zdroj: Environmental pollution (Barking, Essex : 1987) [Environ Pollut] 2021 Jul 15; Vol. 281, pp. 116989. Date of Electronic Publication: 2021 Mar 22.
DOI: 10.1016/j.envpol.2021.116989
Abstrakt: First flush or the first pore volume of effluent eluted from biofilters at the start of rainfall contributes to most pollution downstream because it typically contains a high concentration of bacterial pathogens. Thus, it is critical to evaluate designs that could minimize the release of bacteria during a period of high risk. In this study, we test the hypothesis of whether an addition of iron-based media to biofilter could limit the leaching of Escherichia coli (E. coli), a pathogen indicator, during the first flush. We applied E. coli-contaminated stormwater intermittently in columns packed with a mixture of sand and compost (70:30 by volume, respectively) and iron filings at three concentrations: 0% (control), 3%, and 10% by weight. Columns packed with a mixture of sand and iron (3% or 10%) without compost were used to examine the maximum capacity of iron to remove E. coli. In columns with iron, particularly 10% by weight, the leaching of E. coli during the first flush was 32% lower than the leaching from compost columns, indicating that the addition of iron amendments could decrease first-flush leaching of E. coli. We attribute this result to the ability of iron to increase adsorption and decrease growth during antecedent drying periods. Although the addition of iron filings increased E. coli removal, the presence of compost decreased the adsorption capacity: exposure of 1 g of iron filings to 1 mg of DOC reduces E. coli removal by 8%. The result was attributed to the alteration of the surface charge of iron and blocking of adsorption sites shared by E. coli and DOC. Collectively, these results indicate that the addition of sufficient amounts of iron media could decrease pathogen leaching in the first flush effluent and increase the overall biofilter performance and protect downstream water quality.
(Copyright © 2021 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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