Natural attenuation of BTEX compounds: Model development and field-scale application

Journal Article · Fri Oct 01 04:00:00 EDT 1999 · Ground Water

DOI:https://doi.org/10.1111/j.1745-6584.1999.tb01163.x· OSTI ID:20000259

Lu, G; Clement, T P; Zheng, C; Wiedemeier, T H

Benzene, toluene, ethyl benzene and xylene (BTEX) dissolved into ground water and migrated from a light nonaqueous phase liquid (LNAPL) source in a sandy aquifer near a petroleum, oil, and lubricants (POL) facility at Hill Air Force Base (AFB), Utah. Field observations indicated that microbially mediated BTEX degradation using multiple terminal electron-accepting processes including aerobic respiration, denitrification, Fe(III) reduction, sulfate reduction, and methanogenesis has occurred in the aquifer. To study the transport and transformation of dissolved BTEX compounds under natural conditions, a reactive flow and transport model incorporating biochemical multispecies interactions and BTEX was developed. The BTEX, oxygen, nitrate, Fe(II), sulfate, and methane plumes calculated by the model agree reasonably well with field observations. The first-order biodegradation rate constants, estimated based on model calibration are 0.051, 0.031, 0.005, 0.004, and 0.002 day{sup {minus}1} for aerobic respiration, denitrification, Fe(III), sulfate reduction, and methanogenesis, respectively. The results of a sensitivity analysis show that the saturated aquifer thickness, hydraulic conductivity, and reaction rate constants are the most critical parameters controlling the natural attenuation of BTEX at this site. The hydraulic conductivity and aquifer thickness were found to be the key factors affecting the restoration of oxygen, nitrate, and sulfate after their interaction with the BTEX plume. The multispecies reactive transport modeling effort, describing BTEX degradation mediated by multiple electron-accepting processes, represents one of the few attempts to date to quantify a complete sequence of natural attenuation processes with a detailed field data set. Because the case study is representative of many petroleum-product contaminated sites, the results and insights obtained from this study are of general interest and relevance to other fuel-hydrocarbon natural attenuation sites.

• Research Organization: Univ. of Alabama, Tuscaloosa, AL (US)
• OSTI ID: 20000259
• Journal Information: Ground Water, Journal Name: Ground Water Journal Issue: 5 Vol. 37; ISSN GRWAAP; ISSN 0017-467X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ALKYLATED AROMATICS
BENZENE
BIODEGRADATION
FIELD TESTS
GROUND WATER
HYDRAULIC CONDUCTIVITY
MATHEMATICAL MODELS
REMEDIAL ACTION
WATER POLLUTION