Drycleaner Site Profiles

Former Base Laundry & Drycleaning Facility, Orlando, Florida

Description
Historical activity that resulted in contamination.

This is a Department of Defense facility (Orlando Naval Training Center) where laundering and drycleaning were performed using PCE and petroleum solvents from the late 1950s until 1994. As many as five drycleaning machines were utilized in the operations. Solvents were stored in ASTs located outside the facility. Solvent was delivered in drums to a loading dock. Several solvent spills, estimated at from 5 - 55 gallons, were reported to have occurred at the loading dock, at the ASTs and inside the facility. Fuel oil was stored in ASTs and USTs and was used as a boiler fluid. A water well, located 75 feet south of the facility was completed in the Floridan aquifer and supplied water for the boiler and laundry operations. Wastewater from laundry operations was discharged to a surge tank located immediately west of the facility and then to a sanitary sewer. The facility is located approximately 375 feet east of a small lake and groundwater flow is westward from the facility to the lake. PCE and its daughter products have been detected in both water and sediment samples collected from the lake. The contaminant source areas at the facility include the soils beneath the building floor slab in the vicinity of the drycleaning machines, the former solvent delivery and storage areas and the surge tank.

Remediation Status: In active remediation


Contaminants
Contaminants present and the highest amount detected in both soil and groundwater.


Contaminant Media Concentration (ppb) Nondetect
cis-1,2-Dichloroethene groundwater 2,000 ppb
Tetrachloroethene (PCE) groundwater 34,000 ppb
Tetrachloroethene (PCE) soil 430 ppb
Trichloroethene (TCE) groundwater 15,000 ppb
Trichloroethene (TCE) soil 27 ppb

Site Hydrology

Deepest Significant Groundwater Contamination:   60ft bgs
Plume Size:   Plume Length: 350ft
Plume Width: 700ft
Average Depth to Groundwater:   6.7ft

Lithology and Subsurface Geology

Upper surficial aquifer
  Fine-grained sand
Depth: 0-17ft bgs
17ft thick
Conductivity: 10ft/day
Gradient: 0.008ft/ft
Lower surficial aquifer
  moderately to well indurated silty, fine-grained sand
Depth: 17-20ft bgs
3ft thick
Conductivity: 40ft/day
 
  fine-grained sand
Depth: 20-54ft bgs
34ft thick
 
  silty, fine, fine to coarse sand with phosphate nodules and shells
Depth: 54-71ft bgs
17ft thick
 
  clayey sand with clay interbeds
Depth: 71ft bgs

Pathways and DNAPL Presence

checkGroundwater
Sediments
checkSoil
checkDNAPL Present

Remediation Scenario

Cleanup Goals:
  Groundwater (MCLs) PCE = 3 ¼g/l; TCE = 3 ¼g/l; cis 1,2-DCE = 70 ¼g/l

Technologies

In Situ Recirculating Wells
 

Why the technology was selected:
The UVB wells were installed as an interim remedial measure to capture and treat contaminated groundwater and prevent it from migrating to the lake located downgradient of the facility.

Date implemented:
December 10, 1997

Final remediation design:
Two UVB (Unterdruck Verdampster Brunnen) or "vacuum vaporizing wells" were installed 300 ft downgradient of the facility, approximately 85 ft apart. The design capture zone for the system was 200 ft wide and 45 ft deep. The wells were constructed of 10-inch diameter schedule 80 PVC with two stainless stell screens (0.01-inch slots). Contaminated groundwater was extracted through the upper screen (3.5-12.5 ft bgs - upper surficial aquifer) utilizing a 1 H.P. Grundfos submersible variable-speed stainless stell pump. The water was treated in an in-well stripping unit (vacuum stripping canister) installed on the top of the wellhead. Treated water was injected through the lower screen interval (39-45 ft bgs - lower surficial aquifer) using a 1/3 H.P. Grundfos KP 250 sump pump. The design flow rate for each submersible pump was 40 gpm. A 5 H.P. Elekror centrifugal blower located at the surface was utilized to generate negative pressure inside the well. Design vacuum was 20 inches of water with a 530 cfm air flow. VOC emissions from the system were estimated to be approximately 2.0 lbs/day and therefore, no emissions treatment system was installed.

Results to date:
Results achieved to date:: The startup pumping rate for the UVB wells was 10 gpm. The sump pumps were almost immediately upgraded to 3/4 H.P. Goulds Submersible pumps (discharge head 60 ft (26 p.s.i.) at 10 gpm. Other early maintenance and operational problems included failed packers, iron precipitation and sand/silt entering the well casings. The effluent injection rate could not be balanced with the influent influent pumping rate (influent pumping rate >effluent injection rate). A holding tank (3 ft x 4 ft) was installed at the surface to receive and hold influent water, until it was injected. However, design pumping rates could not be achieved. In the second year of system operation, a biocide injection system was installed. Groundwater extraction rates were 4-6 gpm and were limited by influent injection rates. The submersible pumps were therefore cycled to operate for 20 minutes of pumping followed by 30 minutes of down time to allow for influent injection (rate ~ 2 gpm). By the fourth quarter of 1999, influent pumping rates were limited to 2 - 2.5 gpm and effective injection rates were approximately 1.5 gpm. Biologic and geochemical fouling was occurring. By May of 2000, injection tests of the lower surficial aquifer revealed that a rate of only 0.46 - 1.0 gpm could be achieved. In the fall of 2000, the UVB wells were shut down and were later converted to a pump & treat system with effluent treated using a shallow tray air stripper. Treated water was discharged to the City of Orlando sewer system.

Costs

Cost for Assessment:
  No costs available from DOD as of this date.
Cost for Operation and Maintenance:
 
Total Costs for Cleanup:
 

Lessons Learned

1. The system never achieved design pumping rates and therefore did not achieve capture of the downgradient portion of the contaminant plume.

2. Influent pumping rates were limited by the rate at which effluent could be injected. Although aquifer testing indicated that the lower surficial aquifer (injection zone) had a higher hydraulic conductivity than the upper surfical aquifer (pumping zone), effluent could not be injected at design rates. There may have been a fouling/precipiation problem in the filter pack or the near screen sediments.

3. It is doubtful that an effective circulation cell ever develped within the aquifer. The distance between the upper screen interval and the lower screen interval was over 27 ft and the lithology between the two screens was described as a silty, fine-grained sand that is moderately to well indurated. This unit likely limited vertical circulation.

4. This system had many operational and maintenance problems including silt/sand entering the well screens, failed packers, biofouling, precipitation, and problems assocated with equalizing influent and effluent pumping rates.

Contacts

David Grabka, project manager
Bureau of Waste Cleanup (MS 4520)
Florida Department of Environmental Protection
2600 Blair Stone Road
Tallahassee, Florida 32399-2400
(850) 245-8999
David.Grabka@DEP.state.fl.us

Steve Tsangaris, contractor
CH2M Hill
4350 West Cypress, Suite 600
Tampa, Florida 33607

Site Specific References

1. Remedial Investigation 1/2001
2. Focused Investigation/ Source Confirmation 5/1997
3. Quarterly Monitoring Activity & Results 1998-2000
4. IRA Work Plan Addendum for UVB Well Upgrade 9/2000