Major Oil Refinery
Free Product Recovery
Southern California |
Evaluated methods to optimize free product recovery from existing and/or new wells. Approximately 50 individual recovery systems were utilized, including remote, solar-powered recovery systems located in areas that did not have access to power. The optimization recommendations included pump replacements, enhanced maintenance, and targeted new well installations. Recommendations were based on the development of conceptual and 3-dimensional data visualization models, and the strategic goals defined by the refinery. |
Chevron, USA
Free Product Remediation
El Segundo, California |
Designed and managed the installation/implementation of a free product recovery system at an active service station site near the Los Angeles International Airport. The system effectively recovered free product from numerous wells without affecting the hydraulic gradient in the area, thus preventing further on-site contamination. |
Fuel Depot
Free Product Remediation
Los Angeles, California |
Releases over 60 years of operation at a large Los Angeles fuel transfer terminal resulted in a large amount of free product in the ground. Early attempts at vapor extraction and treatment by a thermal oxidizer proved unsuccessful due to the high concentration of fuel in the vapor. The required dilution of the vapors resulted in significant supplemental fuel costs and variations in the concentration resulted in safety shutdowns of the system to prevent excess temperatures.
The goals for the cleanup needed to recognize the value of the recovered product in liquid and vapor phase, safety and reliability of the equipment, and the overall recovery rate needed to be increased to prevent the plume from intruding on nearby developments. In order to meet these goals a remediation system was designed based on internal combustion engines (Ford 460). The high vacuum of the engine can be used to extract vapor and liquid product. In addition, the vapors can be used as the fuel source to power the engine. Although the engines can process nearly eight times the hydrocarbon concentration of a thermal oxidizer, the extremely high concentrations reduced the overall flow capacity of the system. To utilize the full system flow capacity and increase the recovery of liquid and vapor product, a chiller system was designed to reduce the concentration of hydrocarbons entering the carburetor of the engine by chilling the vapor stream to the hydrocarbon dew point allowing the vapor to become liquid to be removed. |
Property Acquisition
In-site Treatment
Hollywood , California |
Samples collected during due diligence prior to a property purchase discovered contamination in the vados zone in unexpected areas. The $20 M purchase was delayed pending removal of the contamination to meet the Los Angeles Regional Water Quality Control Board requirements and the potential buyer´s clean-up goals. The primary goal for the cleanup was to meet very stringent clean-up goals, ensure the action was cost effective given the known value of the property, and minimize the time property transfer is delayed.
The remediation methods were designed and managed over a three month period. Due to the large area to be remediated, dig and haul was too expensive. Chemical oxidation was chosen due to the shallow nature of the contamination and the ability to reach low clean-up goals in a timely manner. Two application methods were required for the oxidation chemicals. In highly permeable soil direct injection would be very cost effective; however, in silty clay areas soil mixing would be used to ensure contact between the chemical oxidant and the contaminate. Multiple applications were planned and a sample verification protocol developed and implemented. In the area where soil mixing was used, there was also a need to stabilize soils with cement to meet compaction standards required by the city.
The project was completed in three months allowing the property transfer. The project met the goals of the RWQCB, property seller, new owner, and the City of Hollywood. |
Rural Gas Station
Free Product Remediation,
In-situ Treatment
Greater Los Angeles area, California |
A gasoline release over a number of years at a large rural gas station resulted in a large plume of free product. Due to the tight soils, the release area was excavated; however, extensive contamination remained in the vados zone above the groundwater. Pneumatic skimmer pumps were placed in several wells to recover free product and minimize the amount of water needing treatment. The free product removal effort was successful; and, within a year, only a sheen remained on the groundwater surface. The tight soils were still highly contaminated. Vapor testing showed a minimal radius of influence and vapor extraction was determined to not be cost effective.
Chemical oxidation followed by biological treatment was selected to reduce the high concentrations and then meet the very low requirements set by the RWQCB. Injection wells were installed and an automatic system, which would fill the well casing several feet above the natural water level was designed. A solution of 3-5% hydrogen peroxide was mixed and injected into each of the wells. Natural iron in the soil acted as the needed catalyst. By filling the well casing and allowing the solution to permeate into the fine silts over time, the stoichiometric amount of oxidant required could be injected at a very low cost.
Once hydrocarbon concentrations were reduced significantly a more dilute solution (500 ppm) of hydrogen peroxide was applied with a nutrient supplement. Naturally occurring bacteria completed the degradation process started by chemical oxidation. Chemical oxidation does affect naturally occurring bacteria but will not sterilize the subsurface. The breakdown byproducts of chemical oxidation are smaller hydrocarbon compounds which are a more readily available food source for bacteria.
The concentration of petroleum hydrocarbons have been reduced to below regulatory levels and the site has been granted closure by the RWQCB pending removal of the wells. |
Revere Copper & Brass
Site Remediation
Site Closure
Industry, California |
EnviroSolve was retained by owner to complete remediation and obtain NFA letter from DTSC so that site could be sold for other commercial use. The owner had spend millions of dollars and four to five years getting the site to the point where buildings had been demolished and known aboveground environmental problems remediated. EnviroSolve supervised demolition and removal of concrete floor slabs and soils contaminated with heavy metals, petroleum hydrocarbons and VOCs. Complete demolition and removal of approximately five acres of concrete floor slabs and remediation of underlying environmental problems required approximately one year. |
ScrewCorp
Site Remediation
Industry, California |
This facility continues to manufacture aerospace fasteners while undergoing soil and groundwater remediation. Soil and groundwater were heavily contaminated with PCE and TCA, making soil vapor extraction with carbon control of air emissions too expensive. A thermal oxidizer with a various sizes permit was used to remove the heaviest VOC contamination from soil. That unit has now been replaced with a carbon based system to minimize operating costs. VOC concentrations in groundwater have been reduced from a peak of 46,000 g/l to less than 1000 g/l. |
VOI-SHAN
Site Remediation
Redondo Beach, California |
This aerospace manufacturing fastener facility, consisting of two manufacturing buildings on approximately 12 acres, was taken out of service and the land developed for other commercial/industrial use. The demolition of the concrete floor slabs and remediation of soil contaminated with chlorinated solvents and heavy metals was completed by EnviroSolve in six months to the issuance of an NFA letter from the Regional Water Quality Control Board. Site remediation included the excavation and onsite treatment of 6000 CY of heavy metal contaminated soil, and the removal and over excavation of at least two below ground clarifiers. Contaminated soil was excavated to MCLs or Action Levels and stockpiled in two soil piles. Excavation limits were controlled by repeated cycles of excavation and sampling the edges of the pit until the desired concentration limits were achieved. The heavy metal contaminated soil was sent to off-site disposal and the chlorinated solvent contaminated soil was remediated by constructing an on-site covered pile underlain with perforated pipe. A 20-HP blower connected to carbon vessels was operated for approximately 90 days to reduce VOC concentrations to non-detectable levels in 50 randomly collected soil samples. |
An employee-owned company
