Remediation Status: In active remediation

Why the technology was selected:
An initial biostimulation treatability study was conducted in the shallow zone hot spot. A larger scale biostimulation injection project in the deeper groundwater zone was selected due to the success of the shallow zone treatability study.

Date implemented:
June 2010 Biostimulation Pilot Test in shallow zone. June-July 2012 Biostimulation in deep zone.

Final remediation design:
Shallow Zone - Enhanced In-situ Bioremediation (EIB) treatability study conducted in June 2010. The EHC® (1% EHC by soil mass) was injected into the upper groundwater zone (at 11-22 feet bls) in the most contaminated part of the plume. A total of 1,570 gallons of slurry (4,400 lbs EHC® ) was injected at eight locations using direct push technology. GW samples collected 7 weeks after the injection indicated significant decreases in the COC concentrations in MW-4A. Deeper Zone EIB in zone B - EHC injection in June 2012 EHC® injections into deeper groundwater zone. There were twenty three injection point into the deeper gw zone. (25 - 38 ft BGS). A total of approximately 17,350 lbs of EHC was injected into twenty three injection points over a 70 ft x 30 ft area.

Results to date:
Shallow Zone A: Two groundwater sampling events have been conducted since the June 2010 injection of EHC. The post-injection results indicated significant changes in cVOC concentrations in the shallow groundwater zone in the immediate vicinity of the injection area (MW-4A), conducted in June 2010. There has been significantly reduced the COC concentrations in source area shallow zone wells. However, significant increases in COC concentrations were noted in nearby deeper zone wells. The oxidation reduction potential (ORP), pH, nitrate, dissolved oxygen (DO),dissolved iron and manganese, and total organic carbon (TOC) were in the favorable range for the growth of anaerobic bacteria that utilize cVOC as electron acceptors. Total eubacteria counts indicated that microbial growth is not inhibited. However, because the concentration of sulfate in groundwater remains high, it is anticipated that a microbial acclimation period of several additional months will be required before conditions are favorable for the complete reductive dechlorination of cVOCs. Deeper GW Zone: No post injections groundwater sampling result are available at this time. Initial result expected in Aug-Sept 2010.

Next Steps:
Currently waiting on results of push probe investigation and deeper zone biostimulation injection event. Need for additional assessment and remediation will be evaluated at that time.

Cost to Design and Implement:
Biostimulation: $81k Deeper Gw Zone Biostimulation: $125k

Date implemented:
June 2004 soil excavation and treatment

Final remediation design:
Soil removal Response Action was conducted in June 2004. Approximately 540 cubic yards of soil were excavated from the area located directly adjacent to the rear of the former Celebrity Dry Cleaners facility. The depth of the excavation was up to 10 feet bls. A storm water sewer inlet and associated line was removed within the excavated area and replace upon completion of the project. Excavated soils were treated onsite with chemical oxidant (0.5 percent solution of potassium permanganate) and were returned to excavation. Physical constraint (e.g. building location, equipment limitations, and monitor well locations) prevent the complete excavation of the source area soils to the target PCE level of 0.050 mg/kg. An SVE piping gallery was installed at the base of the excavation - but this has not been used to date.

Results to date:
Soil: The 2004 excavation removed the majority of the source area soils but due to physical constraints, there were affected soils (exceeding cleanup goals) which were left in place. No soil cleanup level excedences where found during confirmatory soils sampling conducted in October 2010 .

Next Steps:
Currently waiting on results of push probe investigation and deeper zone biostimulation injection event. Need for additional assessment and remediation will be evaluated at that time.

Cost to Design and Implement:
Soil Excavation: Cost data not available

Why the technology was selected:
Soil excavation was selected as the most effective means of source area removal.

Date implemented:
June 2004 soil excavation and treatment

Final remediation design:
Soil removal Response Action was conducted in June 2004. Approximately 540 cubic yards of soil were excavated from the area located directly adjacent to the rear of the former Celebrity Dry Cleaners facility. The depth of the excavation was up to 10 feet bls. A storm water sewer inlet and associated line was removed within the excavated area and replace upon completion of the project. Excavated soils were treated onsite with chemical oxidant (0.5 percent solution of potassium permanganate) and were returned to excavation. Physical constraint (e.g. building location, equipment limitations, and monitor well locations) prevent the complete excavation of the source area soils to the target PCE level of 0.050 mg/kg. An SVE piping gallery was installed at the base of the excavation - but this has not been used to date.

Results to date:
Soil: The 2004 excavation removed the majority of the source area soils but due to physical constraints, there were affected soils (exceeding cleanup goals) which were left in place. No soil cleanup level excedences where found during confirmatory soils sampling conducted in October 2010 .

Next Steps:
Currently waiting on results of push probe investigation and deeper zone biostimulation injection event. Need for additional assessment and remediation will be evaluated at that time.

Cost to Design and Implement:
Soil Excavation: Cost data not available