PCE Aerobic Bioremediation by Key-hole Source Removal

CL-Out aerobic PCE bioremediation in a keyhole treatmentreduced the mass of contamination near the source and down gradient concentrations in the plume.  At a former manufacturing facility in Ohio the concentration of PCE near the source was over 100,000 ug/L.  Down gradient of the source the PCE concentrations were less than 10% of the source concentration.  Aggressive treatment in the source area reduced the source concentration and in the down gradient plume.

Source area concentrations decreased as follows after one treatment with CL-Out bioremediation:

  • PCE decreased from 120,000 to 12 ug/L.
  • TCE decreased from 2,000 to 12 ug/L
  • Cis 1,2-DCE decreased from 9,500 to 8,100 ug/L.
  • Vinyl chloride, however, increased from 1,200 to 22,000 ug/L.

The vinyl chloride increased as the aggressive cometabolic treatment stimulated  incomplete reductive dechlorination by other naturally occuring organisms.

Down gradient from the source, the concentrations decreased with slight to no increase in daughter products.  The  down gradient plume had the following results:

  • PCE decreased from 5,000 to 1,600 ug/L.
  • TCE decreased from 43 ug/L to BDL.
  • Cis 1,2-DCE decreased from 140 to 23 ug/L.
  • Vinyl chloride  was not detected before or after treatment.

Keyhole treatment was a cost effective approach to reducing the mass of contamination in a ground water plume by focusing aggressive treatment on the source area.  Concentrations in the rest of the plume decreased as the microbes and treated water dispersed through the plume.

Aerobic PCE Bioremediation By Cometabolism

CL-Out is a consortium selected for aerobic PCE bioremediation.  CL-Out cometabolizes PCE by growing on a simple sugar and producing a metabolic enzyme to degrade PCE.  The microbes produce a dioxygenase enzyme that breaks the carbon bond in PCE.  This reaction eliminates the biproducts of reductive dechlorination.  Also, the synergistic effect of the CL-Out consortium cometabolizes the full suite of chloroethenes and chloroethanes.

Click here to learn more about CL-Out bioremediation.

Aerobic Cometabolism of TCE and 1,4-Dioxane

Field Demonstration of  CL-Out Bioremediation

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.

 

 

1,1,1-TCA Bioremediation at an Industrial Site in Dayton, Ohio

Fast, Economical Site Cleanup

CL-Out bioremediation reduced the concentration of 1,1,1-TCA in ground water at a steel manufacturing facility in Dayton, Ohio. Following implementation of ozone treatment and high vacuum extraction for more than 2 years, the contaminant concentrations remained high.  Bioaugmentation followed up on these treatments and reduced the 1,1,1-TCA concentration very quickly.  Within 30 days of bioaugmentation, the source area contaminant concentration decreased by 80%.  After a second application, the concentration decreased from the pre-treatment concentration of 1,100 ug/L to 1.4 ug/L.  The bioaugmentation effect was observed as far as 250 feet downgradient where the concentrations decreased by more than 50%.  Click here for the full case study.

 

 

TCE and 1,1,1-TCA Bioremediation at Indiana Industrial Site

Fast and Economical Site Remediation

TCE and 1,1,1-TCA bioremediation by CL-Out organisms reduced contaminant concentrations  in ground water under a drum storage area at a central Indiana industrial site.  After  three  monthly applications  of CL-Out microbes, the in situ treatment reduced total maximum CVOC concentrations from 102 mg/L to 3 mg/L in less than 6 months. Click here to view the complete case study.

Bioremediation of a Dry Cleaners

Cost-effective Bioremediation of a Dry Cleaners Quickly Removed Contamination

Historical operations at a Houston area dry cleaners resulted in a chlorinated solvent plume (perchloroethylene or PCE) in the shallow ground water. 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 on-going 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 to view the aerobic cometabolic degradation pathway.

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