CL-Out bioremediation continued to show outstanding results in bioremediation of PCE, TCE and other chlorinated solvents at three recent applications. Results show more than 90% PCE removal with a single application of CL-Out for in situ soil or ground water treatment. The PCE remediation did not cause an increase in vinyl chloride showing that the breakdown pathway was by dioxygenase cometabolism and not by reductive dechlorination.

A site in Massachusetts showed the following ground water results:
PCE 1,100 ug/L reduced to 30 ug/L
TCE 39 ug/L reduced to 5.6 ug/L
No other daughter products were detected.

Ground water remediation in Florida showed these results:
PCE 182 ug/L reduced to 16.1 ug/L
TCE 9.823 ug/L reduced to 2.77 ug/L
cis DCE 3.26 ug/L reduced to 0.282 ug/L
vinyl chloride was not detected before or after bioremediation.

Soil contamination at a site in New Jersey followed the same trend:
PCE 690 ug/L reduced to less than 5 ug/L
TCE 7,980 ug/L reduced to less than 810 ug/L
No breakdown products were detected.

These sites join the hundreds of sites remediated by CL-Out aerobic cometabolism.

Case Study: Industrial Site, Houston, Texas

Site Summary
CL-Out® bioaugmentation was implemented in combination with dual phase extraction at an industrial site near Houston, Texas to remove trichloroethylene (TCE) from ground water. The overlying contaminated soil was excavated, but perched ground water and a deeper aquifer had TCE concentrations greater than 10,000 µg/L. A dual-phase vacuum extraction system was installed to control the ground water gradient and increase distribution of the CL-Out® organisms in the aquifer. The TCE concentrations were reduced by 99.9% in one year.

Geology and Hydrogeology
The site is located on coastal plain sediments characteristically interbedded sands, silts and clays. The first impacted ground water was a thin perched layer 16 to 18 feet below ground surface. A more transmissive, water bearing zone was at 25 to 30 feet deep. Both water-bearing layers and the interbedded fine-grained layers had TCE concentrations above regulatory standards.

Contamination
High concentrations of TCE were present in perched and deeper ground water. Prior to treatment, a small area of soil less than 500 square feet had TCE concentrations greater than 20,000 µg/L. The underlying impacted perched ground water area was the same size and had TCE concentrations up to 30,000 µg/L. The TCE migrated laterally in the underlying deeper ground water where the TCE concentrations were greater than 10,000 µg/L. The area of the deeper ground water plume was approximately 30,000 square feet.

Remediation
The contaminated unsaturated soil was excavated for treatment to the perched ground water. The perched ground water was treated by a combination of potassium permanganate and vapor extraction. The deeper aquifer was treated by a combination of dual-phase extraction and CL-Out® bioremediation.

CL-Out® was applied eight times between January, 2010 and February, 2011. During each application 55 to 110 gallons of CL-Out® was injected into the ground water. The dual-phase extraction system was used to control the ground water gradient and induce greater distribution of the CL-Out® microbes. Periodic plate count analysis of the microbial population in the treated aquifer was completed to guide where and when the CL-Out® population should be supplemented. The repeat applications were on approximately 4 to 6 week intervals.

Results
Following one year of bioaugmentation, the contaminant concentrations were reduced by more than 99%. The daughter products caused by incomplete natural breakdown were removed as well as the TCE. The following table shows the contaminant concentration trends in the treatment area.

A 30 acre bulk fuel facility is ready for reuse after remediation of nearly 100,000 tons of petroleum-contaminated soil in an urban setting near Los Angeles. Bulldog Green Remediation of Walnut Creek, California used a proprietary ex situ treatment process combining Petrox organisms in a custom blend to remediate the soils. All soil was treated and reused on site. This closed-loop process eliminated 8,000 truck loads of soil from the roads and landfills in southern California.

The treatment process reduced contaminant concentrations from typical levels of 1,000 to 10,000 mg/kg to less than 100 mg/kg in less than 30 days. This rapid treatment rate made possible continuous cycling from excavation, through treatment, and back filling.

The site is now ready for reuse as a park and other development.