In Situ Lifetimes and Kinetics of a Reductive Whey Barrier and an Oxidative ORC Barrier in the Subsurface

Abstract

Permeable reactive barriers (PRB) are being used to engineer favorable field conditions for in-situ remediation efforts. Two redox adjustment barriers were installed to facilitate a 10-month research effort on the fate and transport of MTBE (methyl tert-butyl ether) at a site called the Michigan Integrated Remediation Technology Laboratory (MIRTL). Thirty kilograms of whey were injected as a slurry into an unconfined aquifer to establish an upgradient reductive zone to reduce O2 concentration in the vicinity of a contaminant injection source. To minimize the impact of contaminant release, 363 kg of oxygen release compound (ORC) were placed in the aquifer as a downgradient oxidative barrier. Dissolved oxygen and other chemical species were monitored in the field to evaluate the effectiveness of this technology. A transient one-dimensional advective-dispersive-reaction (ADR) model was proposed to simulate the dissolved oxygen transport. The equations were solved with commonly encountered PRB initial and constant/variable boundary conditions. No similar previous solution was found in the literature. The in-situ lifetimes, based on variable source loading, were estimated to be 1,661 and 514 days for the whey barrier and ORC barrier, respectively. Estimates based on either maximum O2 consumption/production or measured O2 curves were found to under- or overestimate the lifetime of the barriers. The pseudo-first-order rate constant of whey depletion was estimated to be 0.303/d with a dissolution rate of 0.04/d. The oxygen release rate constant in the ORC barrier was estimated to be 0.03/d. This paper provides a means to design and predict the performance of reactive redox barriers, especially when only limited field data are available.

Non-aqueous phase liquid-contaminated soil remediation by ex situ dielectric barrier discharge plasma

“…Soil remediation is commonly performed by technologies (e.g., thermal treatment, soil vapor extraction and bioremediation) based on the injection of steam, oxygen or remedial solutions, including permanganate, dithionate or nutrient amendments for bioremediation (Devlin and Barker 1994;Schnarr et al 1998;Istok et al 1999;Triplett Kingston et al 2010). Aqueous solutions may be injected for the purposes of flushing or to promote the in situ degradation of contaminants (Barcelona and Xie 2001;Devlin et al 2004). Most of the soil remediation technologies have a limited NAPL removal efficiency due to the retention of pollutants in low-permeability zones (e.g., soil vapor extraction) (Brusseau et al 2010;Carroll et al 2012) applicable to source zones composed of volatile organic contaminants (e.g., air sparging, supersaturated water injection) (Nelson et al 2009;Adams et al 2011).…”

Field Study of Enhanced TCE Reductive Dechlorination by a Full‐Scale Whey PRB

“…Within the plume, the thickness of the layer of glacial deposits ranged from 2.0 to 19.5 m. The water table elevation on site varied from 3.0 to 4.5 m below ground surface (bgs). Beneath comprehensive study of donor material efficiencies, loading frequencies, and application design (Barcelona and Xie 2001;Barcelona 2005).…”

“…A wide variety of complex electron‐donor materials are also being used to enhance the rates of contaminant biodegradation (Nyer 2003). Complex carbon substrates including emulsified vegetable oil, Hydrogen Release Compound (HRC) ® , lactate syrup, mulch, molasses, and dairy whey have been employed to develop reducing conditions (Barcelona and Xie 2001) and, as sources of electron donor, to stimulate microbially‐mediated, anaerobic reductive dechlorination of CEs (Yang and McCarty 2000a; Lendvay et al 2003; Rodriguez et al 2004; ITRC 2005; Borden 2007; Hirschorn et al 2007; Katsenovich et al 2007; Lu et al 2008). Performance and cost evaluations of carbon substrate biobarriers await the comprehensive study of donor material efficiencies, loading frequencies, and application design (Barcelona and Xie 2001; Barcelona 2005).…”

Chlorobenzene biodegradation under consecutive aerobic–anaerobic conditions

“…Oxygen, as the terminal electron acceptor, can be provided via the gas phase (in situ air sparging, in-well aeration), via the liquid phase (hydrogen peroxide amendments), or via the solid phase (oxygen release compounds) [1][2][3][4]. Oxygen, as the terminal electron acceptor, can be provided via the gas phase (in situ air sparging, in-well aeration), via the liquid phase (hydrogen peroxide amendments), or via the solid phase (oxygen release compounds) [1][2][3][4].…”

“…Groundwater aeration strategies make use of the capability of indigenous bacteria to degrade organic pollutants aerobically. Oxygen, as the terminal electron acceptor, can be provided via the gas phase (in situ air sparging, in-well aeration), via the liquid phase (hydrogen peroxide amendments), or via the solid phase (oxygen release compounds) [1][2][3][4].…”