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Optimizing Post Remediation Groundwater Performance with Enhanced Microbiological Analyses

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Joshua Orris

Results of geophysics and pneumatic injection pilot tests during 2003 2007 yielded significant positive results for injection delivery design and contaminant mass treatment, resulting in permanent shut-down of an existing groundwater Pump & Treat system. Accessible source areas were subsequently removed (2011) by soil excavation and treated with the placement of Emulsified Vegetable Oil EVO and zero-valent iron ZVI to accelerate treatment of impacted groundwater in overburden and weathered fractured bedrock. Post pilot test and post remediation groundwater monitoring has included analyses of CVOCs, organic fatty acids, dissolved gases and QuantArray速 -Chlor to quantify key microorganisms (e.g., Dehalococcoides, Dehalobacter, etc.) and functional genes (e.g., vinyl chloride reductase, methane monooxygenase, etc.) to assess potential for reductive dechlorination and aerobic cometabolism of CVOCs. In 2022, the first commercial application of MetaArray was performed at the site. MetaArray utilizes statistical analysis, such as principal component analysis and multivariate analysis to provide evidence that reductive dechlorination is active or even that it is slowing. This creates actionable data allowing users to save money by making important site management decisions earlier. The results of the MetaArray analysis support vector machine (SVM) identified groundwater monitoring wells with a 80% confidence that were characterized as either Limited for Reductive Decholorination or had a High Reductive Reduction Dechlorination potential. The results of MetaArray will be used to further optimize the sites post remediation monitoring program for monitored natural attenuation.

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Optimizing Post Remediation Groundwater Performance with Enhanced Microbiological Analysis Authors: Joshua Orris, Antea Group USA and Jack Sheldon, Antea Group USA Session: G2 Group: #1 INTRODUCTION APPROACH RESULTS AND CONCLUSIONS Case Study: Former specialty chemical manufacturing facility located New Jersey was actively undergoing investigations and remediation since the late 1990s. Chlorinated volatile organic compounds (CVOCs); 1,1,1 trichloroethane (TCA), trichloroethylene (TCE) and their respective degradation products were identified as primary Chemicals of Concern (COCs) An Interim Remedial Measure (IRM), groundwater recovery and treatment system was operational from 2001 to 2006 designed for hydraulic control A unique strain of dehalococcoides were identified during bench scale testing that were naturally degrading CVOCs at a low pH range of 5.8-6.0 Significant concentrations of both Biotic and Abiotic degradation products had been detected in groundwater samples August 2002, a microbiological bench scale study was completed to evaluate the potential for anaerobic biodegradation, specifically reductive dechlorination to occur August 2002 Bench Scale Results Confirmed anaerobic conditions along with elevated Chloride concentrations were detected at select monitoring wells suggesting prior CVOC reduction had occurred Low concentrations of chloroethane and a lack of preferable organic acids indicated that the microbial degradation of TCA was limited by a lack of nutrients Abiotic breakdown product pathways of TCA to Vinyl Chloride were detected Hypothesis: if sufficient nutrients were provided it was likely that the abiotic degradation of TCA would decrease and the anaerobic biodegradation of TCA would increase Elevated concentrations of 1,1-DCE, the abiotic breakdown product, were detected; but with lower concentrations of Vinyl Chloride, which is the biotic byproduct of 1,1-DCE. This conditions suggested that the microbial degradation system was nutrient limited HRSCMiHPT Enhanced Pilot Tests & Full Scale Design: Borehole geophysics completed in bedrock open borehole injection wells and existing groundwater monitoring well network Leveraged data visualization with development of a 3D-Conceptual Site Model (3DCSM) Co-Injection application of Emulsified Vegetable Oil (EVO) and zero-valent iron (ZVI) delivery for enhanced dechlorination biodegradation Enhanced targeted injection well design for pneumatic fracturing and injection that yielded increased Radius of Influence for contaminant treatment Successful pilot testing resulted in a broader pneumatic injection full scale application of EVO/ ZVI Due to the efficiently targeted injection design, the groundwater Pump and Treatment system was permanently shut-down and decommissioned resulting in a cost savings of $180,000 per year Accessible source areas were removed during facility renovations and expansions in 2007 and a supplemental source area that was delineated with High Resolution Site Characterization (HRSC), MiHPT was removed and treated with EVO/ZVI prior to backfilling to accelerate treatment of contaminated groundwater present within the perched and intermediate upper bedrock Excavated contaminated materials were treated onsite with a patented process called Mobile Steam Distillation by EVO Corporation 3D-Conceptual Site Model Excavation of Source Material Pneumatic Injection Manifold Mobile Steam Distillation treatment Post Remediation Monitoring: Optimized Monitoring Well Network Sampling & Analysis Plan included: CVOCs, organic fatty acids, dissolved gases and QuantArray速 - Chlor by Microbial Insights to quantify key microorganisms (e.g. Dehalococcoides, Dehalobacter) and functional genes (e.g. vinyl chloride reductase, methane monooxygenase etc..) to assess potential for reductive dechlorination and aerobic co-metabolism of CVOCs QuantArray速- Chlor Microbial Population Summary Enhanced Post Remediation Monitoring: The sites remedial strategy remains aligned with Monitored Natural Attenuation in association with dechlorination In 2022, the FIRST commercial application of MetaArray by Microbial Insights was performed at the site MetaArray utilizes statistical analysis, such as principal component analysis and multivariate analysis to provide evidence that reductive dechlorination is active or even that is slowing The results of MetaArray analysis identified groundwater monitoring wells with a 80% confidence that were characterized as either Limited for Reductive Dechlorination or had a High Reductive Dechlorination potential The results of MetaArray will be used to further optimize the sites post remediation monitoring program for natural attenuation Connect with Josh Orris: Connect with Jack Sheldon:

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Optimizing Post Remediation Groundwater Performance with Enhanced Microbiological Analyses

  • 1. Optimizing Post Remediation Groundwater Performance with Enhanced Microbiological Analysis Authors: Joshua Orris, Antea Group USA and Jack Sheldon, Antea Group USA Session: G2 Group: #1 INTRODUCTION APPROACH RESULTS AND CONCLUSIONS Case Study: Former specialty chemical manufacturing facility located New Jersey was actively undergoing investigations and remediation since the late 1990s. Chlorinated volatile organic compounds (CVOCs); 1,1,1 trichloroethane (TCA), trichloroethylene (TCE) and their respective degradation products were identified as primary Chemicals of Concern (COCs) An Interim Remedial Measure (IRM), groundwater recovery and treatment system was operational from 2001 to 2006 designed for hydraulic control A unique strain of dehalococcoides were identified during bench scale testing that were naturally degrading CVOCs at a low pH range of 5.8-6.0 Significant concentrations of both Biotic and Abiotic degradation products had been detected in groundwater samples August 2002, a microbiological bench scale study was completed to evaluate the potential for anaerobic biodegradation, specifically reductive dechlorination to occur August 2002 Bench Scale Results Confirmed anaerobic conditions along with elevated Chloride concentrations were detected at select monitoring wells suggesting prior CVOC reduction had occurred Low concentrations of chloroethane and a lack of preferable organic acids indicated that the microbial degradation of TCA was limited by a lack of nutrients Abiotic breakdown product pathways of TCA to Vinyl Chloride were detected Hypothesis: if sufficient nutrients were provided it was likely that the abiotic degradation of TCA would decrease and the anaerobic biodegradation of TCA would increase Elevated concentrations of 1,1-DCE, the abiotic breakdown product, were detected; but with lower concentrations of Vinyl Chloride, which is the biotic byproduct of 1,1-DCE. This conditions suggested that the microbial degradation system was nutrient limited HRSCMiHPT Enhanced Pilot Tests & Full Scale Design: Borehole geophysics completed in bedrock open borehole injection wells and existing groundwater monitoring well network Leveraged data visualization with development of a 3D-Conceptual Site Model (3DCSM) Co-Injection application of Emulsified Vegetable Oil (EVO) and zero-valent iron (ZVI) delivery for enhanced dechlorination biodegradation Enhanced targeted injection well design for pneumatic fracturing and injection that yielded increased Radius of Influence for contaminant treatment Successful pilot testing resulted in a broader pneumatic injection full scale application of EVO/ ZVI Due to the efficiently targeted injection design, the groundwater Pump and Treatment system was permanently shut-down and decommissioned resulting in a cost savings of $180,000 per year Accessible source areas were removed during facility renovations and expansions in 2007 and a supplemental source area that was delineated with High Resolution Site Characterization (HRSC), MiHPT was removed and treated with EVO/ZVI prior to backfilling to accelerate treatment of contaminated groundwater present within the perched and intermediate upper bedrock Excavated contaminated materials were treated onsite with a patented process called Mobile Steam Distillation by EVO Corporation 3D-Conceptual Site Model Excavation of Source Material Pneumatic Injection Manifold Mobile Steam Distillation treatment Post Remediation Monitoring: Optimized Monitoring Well Network Sampling & Analysis Plan included: CVOCs, organic fatty acids, dissolved gases and QuantArray速 - Chlor by Microbial Insights to quantify key microorganisms (e.g. Dehalococcoides, Dehalobacter) and functional genes (e.g. vinyl chloride reductase, methane monooxygenase etc..) to assess potential for reductive dechlorination and aerobic co-metabolism of CVOCs QuantArray速- Chlor Microbial Population Summary Enhanced Post Remediation Monitoring: The sites remedial strategy remains aligned with Monitored Natural Attenuation in association with dechlorination In 2022, the FIRST commercial application of MetaArray by Microbial Insights was performed at the site MetaArray utilizes statistical analysis, such as principal component analysis and multivariate analysis to provide evidence that reductive dechlorination is active or even that is slowing The results of MetaArray analysis identified groundwater monitoring wells with a 80% confidence that were characterized as either Limited for Reductive Dechlorination or had a High Reductive Dechlorination potential The results of MetaArray will be used to further optimize the sites post remediation monitoring program for natural attenuation Connect with Josh Orris: Connect with Jack Sheldon: