Demonstration of a Microbiologically Enhanced Vertical Ground Water Circulation Well Technology at a Superfund Site

Abstract

A full‐scale ground water circulation well (GCW) system was installed and operated to demonstrate in situ remediation of soil and ground water impacted with a mixture of chlorinated and nonchlorinated organic compounds at a Superfund site in upstate New York. System performance and applicability under site‐specific conditions were evaluated based on the system's ability to meet the New York State Department of Environmental Conservation (NYSDEC) cleanup goals for target compounds in ground water and soil. Contaminants from the unsaturated zone were mobilized (volatilized) by one‐way vacuum extraction, and treated via enhanced biodegradation (bioventing). In the saturated zone, contaminants were mobilized by soil flushing (solubilized) and treated by a combination of air stripping and biodegradation. An in situ aqueous phase bioreactor, and an ex situ gas phase bioreactor, were integrated into the system to enhance treatment via bioremediation. After 15 months of operation, the mass of target contaminants in soil and ground water combined had been reduced by 75%. Removal by biological mechanisms ranged from 35% to 56% of the total observed mass reduction. The in situ and the ex situ bioreactors mineralized 79% and 76%, respectively, of their target biodegradable contaminant loads. Results indicate that some mass reduction in target contaminants may have been from aerobic and aerobic processes within the circulation cell. Nonchlorinated compounds were relatively easy to mobilize (volatilize, solubilize, and/or transport) and treat when compared to chlorinated compounds. The data collected during the 15‐month study indicate that remediation could be accomplished at the Sweden‐3 Chapman site using the technology tested.

Optimization Strategies for in Situ Groundwater Remediation by a Vertical Circulation Well Based on Particle‐Tracking and Node‐Dependent Finite Difference Methods

“…The applicability and limitation of this simplified conceptual model for dealing with realistic field case problems are elaborated as follows. First, the operational scale of the VCW is in the range of a few meters to tens of meters, as stated in many previous investigations (e. g., Elmore & Deangelis, 2004;Johnson & Simon, 2007;Lakhwala et al, 1998;Miller & Elmore, 2005;US EPA, 1998). With such a small scale, the variations of hydraulic parameters are usually quite limited, unless one is dealing with a strongly heterogeneous system.…”

Efficacy of forming biofilms by Pseudomonas migulae AN-1 toward in situ bioremediation of aniline-contaminated aquifer by groundwater circulation wells

“…In view of great potentials for in situ remediation of aquifer, many researchers focus on the innovation of GCWs configuration and promotion of remediation efficiency. Lakhwala et al (1998) operated a GCW system to in situ remediate soil and groundwater simultaneously impacted with a mixture of chlorinated and non-chlorinated organic compounds at a Superfund site in upstate New York and the reduction for them was with an average of 52 and 88 %, respectively. Blanford et al (2001) used hydroxypropyl-betacyclodextrin as a surfactant to enhance the removal of lowsolubility organic contaminants by GCWs at a Superfund site in Tucson, Arizona and the removal efficiency of trichloroethene concentration was 94 %.…”

Groundwater flow numerical model to evaluate the water mass balance and flow patterns in Groundwater Circulation Wells (GCW) with varying aquifer parameters

“…The circulation induced by GCW may generate water oxygenation due to the induced turbulence, stimulating the in-situ aerobic biodegradation (Lakhwala et al 1998) with the simultaneous advantage of accelerating the remediation times in aquifers that have unfavorable geochemical properties to microbial activity (Semprini et al 1990).…”