CL-Out Bioremediation of Groundwater in Clay Soils

CL-Out bioremediation of groundwater in clay soils reduced concentrations of PCE and TCE at a former dry cleaners in Illinois.  In just over 2 weeks after injection, CL-Out microbes cut the contaminant concentrations in half.

  • PCE from 62.2 to 25.6 mg/L
  • TCE from 11.2 to 6.0 mg/L
  • Cis 1,2-DCE from 3.8 to 1.2 mg/L
  • Vinyl chloride less than 0.001 mg/L before and after treatment

The remediation continues as the microbes grow and cometabolize the residual contamination.  Even in tight clay soils the aerobic cometabolism remediates dry cleaning solvents without producing vinyl chloride or other dangerous by products.

Aerobic Cometabolism of TCE and 1,4-Dioxane – Field Demonstration

In a pilot study to compare aerobic cometabolism with anaerobic reductive dechlorination  to remediation TCE and 1,4-dioxane at a former industrial facility in New Jersey, aerobic cometabolism reduced the concentrations of both compounds while anaerobic reductive dechlorination was unsuccessful.  For aerobic cometabolism, CL-Out microbes were injected into the aquifer to a depth of 60 to 90 feet below ground.  The pilot treatment area was 500 square feet.  Monitoring wells were placed upgradient, sidegradient and downgradient of the injection point.  Ground water samples were taken on a monthly basis for 9 months.

The results showed that complete TCE mineralization, without the production of daughter products, was measured within the first month.  CL-Out bioremediation removed 80% of the TCE at 40 feet downgradient in less than three months.  CL-Out bioremediation reduced the 1,4-dioxane concentration to below detection limits at 20 and 40 feet downgradient in the first month.

Click here to view a summary case study.



Brownfield Plan Included CL-Out Bioremediation

A brownfield plan included Cl-Out bioremediation to reduce high concentrations of TCE and other contaminants in ground water at an industrial site near Newark, New Jersey. 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.

CL-Out Bioaugmentation Following ISCO to Remediate TCE

CL-Out bioremediation was used to remediate ground water at an active manufacturing plant in eastern Massachusetts after ISCO treatment of TCE in groundwater reached a limit.  CL-Out was selected because the aquifer was naturally aerobic.  CL-Out cometabolizes TCE and other chlorinated solvents under aerobic conditions by producing an oxygenase enzyme that breaks the carbon to carbon bond.  Under aerobic conditions daughter products such as DCE and vinyl chloride are not formed.  30 days after one application of CL-Out the TCE concentration was reduced by 97% and the site remediation goals were achieved. Click here to download the case study.

TCE Bioremediation Rates

The following chart is a compilation of TCE bioremediation rates by CL-Out microbes.  This data is from eleven different sites where ground water was contaminated by trichloroethylene (TCE) and remediatedby CL-Out microbes.  The sites represent all kinds of geological conditions with the full range of TCE concentrations in ground water.

Overall, the results show an average removal rate of 97% .  However, the final TCE concentration reached below detection limits on two sites, and an additional three had greater than 99% removal.