Soil attenuation of As(III, V) and Se(IV, VI) seepage potential at ash disposal facilities

Seunghun Hyun, Linda S. Lee

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Leachate from ash landfills is frequently enriched with As and Se but their off-site movement is not well understood. The attenuation potential of As and Se by soils surrounding selected landfills during leachate seepage was investigated in laboratory column studies using simulated ash leachate. As(III, V) and Se(IV, VI) concentrations as well as pH, flow rate, and a tracer were monitored in influent and effluent for up to 800 pore volumes followed by sequential desorption, extraction, and digestion of column segments. Column breakthrough curves (BTCs) were compared to predictions based on previously measured sorption isotherms. Early As(V) breakthrough and retarded As(III) breakthrough relative to predicted BTCs are indicative of oxidative transformation during seepage. For Se(VI), which exhibits linear sorption and the lowest sorption propensity, measured BTCs were predicted fairly well by equilibrium sorption isotherms, except for the early arrival of Se(IV) in one site soil, which in part, may be due to higher column pH values compared to batch isotherms. Most of the As and Se retained by soils during leaching was found to be strongly sorbed (60-90%) or irreversibly bound (10-40%) with <5% readily desorbable. Redox potential favoring transformation to the more sorptive valence states of As(V) and Se(IV) will invoke additional attenuation beyond equilibrium sorption-based predictions. With the exception of Se(IV) on one site soil, results indicate that attenuation by down-gradient soils of As and Se in ash landfill seepage will often be no less than what is predicted by equilibrium sorption capacity with further attenuation expected due to favorable redox transformation processes, thus mitigating contaminant plumes and associated risks.

Original languageEnglish
Pages (from-to)2132-2139
Number of pages8
JournalChemosphere
Volume93
Issue number9
DOIs
Publication statusPublished - 2013 Nov 1

Fingerprint

Ashes
Seepage
Waste disposal
seepage
Sorption
ash
sorption
Soils
breakthrough curve
Land fill
Isotherms
isotherm
soil
leachate
landfill
redox potential
prediction
Leaching
digestion
Effluents

Keywords

  • Ash landfill
  • Attenuation
  • Seepage
  • Sorption

ASJC Scopus subject areas

  • Environmental Chemistry
  • Chemistry(all)

Cite this

Soil attenuation of As(III, V) and Se(IV, VI) seepage potential at ash disposal facilities. / Hyun, Seunghun; Lee, Linda S.

In: Chemosphere, Vol. 93, No. 9, 01.11.2013, p. 2132-2139.

Research output: Contribution to journalArticle

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