In Situ Bioremediation Using Hydrogen Release Compound® Or Other Amendments At Four Drycleaner Sites, Various Locations

Site Name:

Multiple (4) Dry Cleaner Sites - In Situ Bioremediation

Location:

- Asian Cleaners, Sanford, FL
- Cypress Village Shopping Center, Bridgeton, MO
- Dry Clean USA #11204, Fort Lauderdale, FL
- Tiger Cleaners, Memphis, TN

Period of
Operation:

- Asian Cleaners - January 11, 2002 - date unspecified
- Cypress Village Shopping Center - technology not yet approved
- Dry Clean USA - December, 2002 - January, 2003 (demonstration only)
- Tiger Cleaners - Expected to begin remediation in April, 2002

Cleanup
Type:

Full-scale remediations and field demonstrations

Technology:
In Situ Bioremediation
- At Asian Cleaners, enhanced bioremediation using triethylphosphate and nitrous oxide was implemented. The system consisted of four biosparging wells screened at 33 to 35 ft bgs - one slant well (installed beneath the drycleaning facility) and three vertical wells. The radius of influence was 31 to 33 ft, and the injection rate was 1 scfm per well, sparging from two wells at a time in one-hour intervals twice per day. Injection concentrations by volume in air were 0.07% to 0.1% for nitrous oxide and 0.007% for triethylphosphate. Propane was scheduled to be added at the end of the treatment regimen to improve microbial concentrations. SVE was used to remove vadose zone contaminants at this site.
- At Cypress Village Shopping Center, use of Hydrogen Release Compound® (HRC®) in the bioremediation process has been evaluated but has not yet been approved.
- At Dry Clean USA, bioremediation using CL Solutions’ Cl-Out was used in a demonstration. The solution was introduced into the subsurface in two events. Three injection wells screened between 5 to 10 bgs were used, and approximately 20 gallons of solution were injected in each well per event, at a rate of 1 gallon - At Tiger Cleaners, HRC® will be injected within and outside the source area, as well as in the contaminant plume. Within the source area, seven horizontal injection points will be drilled under the slab of the building, injecting a total amount of approximately 4,000 lbs of HRC®. per minute.

Cleanup Authority:
State

Contacts:
Varied by site

Contaminants:
Chlorinated Solvents
- All of the sites were contaminated with PCE, TCE, cis- and trans-1,2-DCE, and vinyl chloride.
- Concentrations varied by site ranging from 5.2 to 87,200 µg/L for PCE, 4.5 to 28,500 µg/L for TCE, 546 to 23,200 µg/L for cis-1,2-DCE, 1,780 to 26,300 µg/L for trans-1,2-DCE, and 1,100 to 2,800 µg/L for vinyl chloride.
- One site (Asian Cleaners) also reported the presence of nonhalogenated volatiles including toluene, p-isopropyltoluene, xylenes, and MTBE.

Waste Source:
Waste and wastewater from drycleaning operations

Type/Quantity of Media Treated:
Groundwater
- Groundwater conditions varied by site
- Plume sizes ranged from 4,375 to 20,000 square feet

Purpose/Significance of Application:
Use of in situ bioremediation to treat chlorinated solvents in groundwater at drycleaner facilities

Regulatory Requirements/Cleanup Goals:
- At all four sites, cleanup goals were based on state regulatory goals or EPA MCLs.
- Specified cleanup goals for groundwater included 3 µg/L for PCE, 3 µg/L for TCE, 70 µg/L for cis-1,2-DCE, 100 µg/L for trans-1,2-DCE, and 1 µg/L for vinyl chloride.

Results:
- No information was provided for Asian Cleaners, Cypress Village Shopping Center, or Tiger Cleaners.
- At Dry Clean USA, sampling of the source area one month after the second and final injection revealed a decrease in PCE and TCE concentrations from 48,300 to 96 µg/L and from 6,110 to 100 µg/L, respectively. Concentrations of cis-1,2-DCE and vinyl chloride increased from 2,950 to 94,500 µg/L and from 890 to 2,810 µg/L, respectively.

Cost Factors:
- Reported design and implementation cost ranged from approximately $51,000 to $150,000
- O&M costs were provided for one site (Asian Cleaners) - $150,000 estimated for 12 months.

Description:
In situ bioremediation was conducted at four drycleaner sites contaminated with chlorinated solvents from drycleaning operations with TCE and PCE as the primary contaminants in groundwater. The concentrations of TCE and PCE contamination varied by site with levels of PCE in groundwater as high as 87,200 µg/L and TCE in groundwater as high as 28,500 µg/L. The remediations, including full-scale and demonstration-scale projects, involved the subsurface injection of substances to promote bioremediation.

In situ bioremediation was performed using triethylphosphate/nitrous oxide at one site and CL Solutions’ Cl-Out at another site. HRC® was evaluated for use at the third site, but has not been approved yet. At the fourth site, bioremediation using HRC® was expected to begin in April, 2002. Results from a sampling event in the source area one month after injection of the Cl-Out solution at Dry Clean USA showed a decrease in PCE and TCE concentrations, and an increase in cis-1,2-DCE and vinyl chloride concentrations.