BTEX Remediation in Groundwater

BTEX Bioremediation

This project demonstrates the rapid bioremediation of BTEX components of petroleum with Petrox bioaugmentation. BTEX contamination in groundwater from a leaking underground storage tank was cost-effectively treated with two applications of Petrox.

The pre-treatment concentrations of Toluene and Xylene were 1,198ppb and 2,408 ppb, respectively. Ten units of Petrox aerobic microbes were injected into the ground water on about June 2, 2002. Within six weeks the concentrations decreased to 515ppb and 690 ppb, Toluene and Xylene, respectively. After a second inoculation in August 2002, the concentrations decreased to 3.7ppb and 16.4 ppb, respectively. There has been a slight rebound in Xylene to 23.8 ppb, and a third inoculation will be implemented to finish the treatment.

The cost to treat this quarter acre plume with Petrox was about $20,000.


Bioremediation of BTEX at an Industrial Site in Florida


Petrox® bioaugmentation was used to remediate ground water contaminated by benzene, toluene, ethylbenzene and xylene (BTEX) at an industrial facility in central Florida (Facility ID No. 8521705). The bioremediation was implemented in perimeter wells around the source area where air sparging and vapor extraction was implemented. This combined approach provided cost-effective, full-site remediation by using complementary technologies.

Remediation Approach and Results

Petrox® was introduced into the contaminated ground water in the perimeter of the source area plume by injection through temporary well points. Two applications of Petrox® were completed. The initial application was in December 2007 and a subsequent application was completed in April 2008. During each application 550 gallons of Petrox® microbial slurry were injected into the ground water through 19 injection points. The treatment covered an area of approximately 7,000 square feet.

The ground water treatment results were monitored by laboratory analysis of ground water samples for the contaminants of concern. The quarterly monitoring results after the applications showed an immediate and continuous decrease in the BTEX concentrations. The following chart shows the total BTEX concentrations in three quarterly sampling events after the implementation of Petrox® bioaugmentation.



This project demonstrates two of the benefits of aerobic bioaugmentation. Petrox® organisms were able to metabolize the BTEX compounds, which were initially at part per million levels, to below detection limits. Bioaugmentation provides active control of the site with hydrocarbon-degrading organisms compatible with air sparging and vapor extraction in the source area, where the contaminant concentrations persisted longer than in the bioaugmentation area.

Petrox® Bioaugmentation in Bedrock

Case Study: Petroleum Remediation in Central New Jersey


Petrox® bioaugmentation was implemented at a petroleum remediation site in Morris County, New Jersey to destroy residual petroleum compounds in ground water. The impacted ground water was in bedrock fractures under and down gradient of a former UST location. The UST was removed and an oxygen release compound was added to the ground water to stimulate bioremediation. However, residual contamination persisted and Petrox® bioremediation was implemented to remove the residual low concentration found at the site.

Geology and Hydrogeology

The bedrock surface was fairly close to the ground surface and the first ground water encountered upon drilling at the site was within the bedrock. Impacted ground water was contained within the fractures near the bedrock surface in a zone estimated to be 40 feet thick.


Low concentrations of benzene, xylene, ethylbenzene and toluene were present in ground water at and down gradient of the former UST cavity. The area of proposed treatment was 3,600 square feet.


Petrox was applied in two monthly applications of 8 units each. One unit of Petrox® is a 55-gallon slurry with a microbial concentration of 109 cfu/ml. ORC socks were installed in treatment wells to provide an oxygen source for the petroleum metabolism.

The monthly Petrox® injections were on May 29, 2009 and June 26, 2009. Post -treatment samples were taken on June 10, 2009 and May 4, 2010. The following table shows the contaminant concentration treads in the treatment area.



The treatment was successful in reducing the BTEX concentration at the site. However, the increase in concentrations after the first treatment showed that there were residual petroleum constituents in the source that was not reflected in the pre-treatment sampling. Petrox® microbes were detected in all of the bedrock sampling points as far as 30 feet down gradient of an injection point. Overall the treatment verified the effectiveness of Petrox® bioaugmentation in fractured bedrock.