Aerobic PCE Cometabolism

Pilot Study Confirms Aerobic Cometabolism of PCE at Kentucky Site

A CL-Out bioremediation pilot study confirmed the PCE could be removed from ground water by aerobic cometabolism.  The pilot study was at the former location of a dry cleaners where PCE wasfound in ground water at 27 parts per billion (ppb).  CL-Out micorbes and dextrose as the metabolic substrate were injected into the ground water upgradient from the sentinal monitoring well.  After 30 days the PCE concentration decreased to 20 ppb.  After 6 months the PCE concentration decreased to 16 ppb.

As the PCE was decreasing the site conditions stayed aerobic.  The dissolved oxygen level in ground water decreased 1.07 mg/L to 0.71 mg/l and the ORP decreased from 99 to 45 mv.

CL-Out cometabolism used a dioxygenase enzyme that is produced constituatively as the metabolic substrate is consumed.  The dioxygenase enzyme destabilizes the carbon bond in the PCE to convert the molecule to an organic acid that leads to complete mineralization.



Compatible Technologies to Improve In-Situ Remediation of Chlorinated Solvents: A Case Study

A chlorinated solvent plume (perchloroethylene or PCE) was discovered
in the shallow ground water as a result of historical operating practices surrounding a
Houston area dry cleaning facility. Permeable shallow soil at the site allowed rapid
vertical migration at the source and lateral migration in the shallow ground water. This
migration resulted in an off-site migration of the plume beneath an apartment complex
causing concern for potential vapor intrusion hazards; as well as, a decrease in property
value. A ground-water extraction and treatment system was installed to address the
dissolved phase concentrations. The system reduced the total volatile organic compound
(VOC) concentration in the source area from 115,400 to 36,500 µg/l. However, over
time, operating maintenance and cost escalations were exceeding the ongoing remedial
benefit. The system was shut down after nine years of operation. A review of available
remedial technologies that could be implemented within the physical constraints of the
site was conducted. In-situ enhanced aerobic bioremediation was selected to address the
remaining ground-water concentrations because of the permeability of the formation, the
relatively aerobic conditions, and the benefit of reducing the risk of VC accumulation.

Click here for a link to the full report from the 2007 Battelle Conference on Bioremediation


CL-Out Bioremediation Meets Aggressive Brownfield Redevelopment Plan

Cl-Out bioremediation reduced high concentrations of TCE and daughter compounds in ground water at an industrial site near Newark, New Jersey to meet an aggressive redevelopment schedule. Using a dynamic remediation plan, three applications of CL-Out microbes followed remediation progress sampling during the site preparation for construction. After reducing the maximum CVOC concentrations from over 8,000 ug/L to less than 20 ug/L, the site met the remediation goals and received a No Further Action Letter from NJDEP. For more information and a detailed case study, click here.

Aerobic Cometabolism of Chlorinated Solvents, Central New Jersey Case Study

CL-Out® was successfully used to remediate solvents in ground water at an operating industrial site in central New Jersey.  The the facility was a manufacturing and plating company with historical petroleum and solvent releases.

Chlorinated solvents were found in the ground water in two plumes covering a combined area of about one half acre.  The contaminants were a mix of chlorinated solvents including 1,1,1-TCA, 1,1-DCE and PCE in low concentrations.    The remediation goal was to reduce the mass of contamination in the ground water plume to prevent mitigate off-site risks.

After the CL-Out application, ground water concentrations in all monitoring wells decreased by more than 80%, which was sufficient to meet the remediation standards.  Click here to download a complete case study.

In-Situ Aerobic Soil and Ground Water Bioremediation of PCE and TCE

CL-Out bioremediation of chlorinated solvents like PCE and TCE is an aerobic cometabolic process.  As these compounds are not directly metabolized under aerobic conditions, the competitive advantage goes to the CL-Out organisms that cometabolize them.  While utilizing a sugar substrate, the CL-Out organisms produce enzymes mono- and dioxygenase that bridge the carbon bond to destabilize the compound.  The solvent is converted to an organic acid that the organism can metabolize.  The benefit is that CL-Out bioremediation can be applied to soils both in situ and ex situ.  Click here for to download a case study.  For further explanation call CL Solutions at 513-284-9540.