Compaction conditions affect the capacity of biochar-amended sand filters to treat road runoff.

Autor: Ghavanloughajar M; Department of Civil and Environmental Engineering, University of California, Los Angeles, USA., Valenca R; Department of Civil and Environmental Engineering, University of California, Los Angeles, USA., Le H; Department of Civil and Environmental Engineering, University of California, Los Angeles, USA., Rahman M; Department of Civil and Environmental Engineering, University of California, Los Angeles, USA., Borthakur A; Department of Civil and Environmental Engineering, University of California, Los Angeles, USA., Ravi S; Department of Earth and Environmental Science, Temple University, Philadelphia, USA., Stenstrom MK; Department of Civil and Environmental Engineering, University of California, Los Angeles, USA., Mohanty SK; Department of Civil and Environmental Engineering, University of California, Los Angeles, USA. Electronic address: mohanty@ucla.edu.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2020 Sep 15; Vol. 735, pp. 139180. Date of Electronic Publication: 2020 May 20.
DOI: 10.1016/j.scitotenv.2020.139180
Abstrakt: Amending roadside soil with adsorbents such as biochar can help remove pollutants from road runoff. To maintain soil stability, the roadside soil requires compaction. However, it is unknown how compaction conditions affect the capacity of biochar-augmented roadside biofilters to infiltrate stormwater and remove pollutants. This work examines the effect of compaction conditions on the release of biochar particles disintegrated during compaction, and the change in their capacity to infiltrate stormwater and remove E. coli. The net loss of biochar particles by mobilization with stormwater was insignificant compared to the biochar remained in the filters. The initial release of biochar particles in wet-compacted biochar columns was greater than that in dry-compacted biochar. The results revealed that compaction can affect the release of biochar particles in a series of three-step processes: generation of particles by disintegration of large biochar under compaction, diffusion of particles deposited near grain walls to bulk pore water, and transport and retention of particles in constricted pore paths based on pore water connectivity. Under similar conditions, compost columns released more particles than biochar columns, suggesting biochar is more stable than compost under compaction. E. coli removal in wet-compacted columns was greater than removal in dry-compacted columns, owing to greater pore path connectivity in wet-compacted columns. These results indicate that addition of moisture during compaction can increase contaminant removal, initial particle release, and infiltration capacity of biochar-augmented sand filters for road runoff treatment. The results would help develop design guidelines for roadside stormwater treatment systems that require compaction of filter media.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2020 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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