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Florida Site Closures With One Petrox Application

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The following applications demonstrate the significant results that can be achieved with a single application of Petrox bioremediation.

Florida Panhandle Gas Station

Facility ID # 32-8520334

Petrox was injected through horizontal drilling to address a ground water plume with limited surface access.  After a single Petrox® application there was significant reduction in the contaminant concentrations.

Sampling Date Benzene Toluene Ethyl benzene Xylene Naph-thalene 2-Methyl naphthalene
Pre- bioaugmentation 11/11/05 4,300 3,000 1,300 5,300 240 48
10/23/07 2,700 4,200 860 5,700 240 41
Post-bioaugmentation 11/06/08 1.7 8.5 0.71 5.1 0.49 0.45
1/22/09 0.88 0.64 0.43 1.3 0.49 0.45

All Concentrations shown in µg/L.

 

Southeast Florida Gas Station

Facility ID 8838788

After removal of USTs, piping and surrounding soils Ground water was treated with 110 gallons of Petrox® by direct injection in June 2009.  Sampling six months after the Petrox® treatment showed significant reductions in all contaminants.

Sampling Date Benzene Toluene Ethylbenzene Total Xylenes
Pre-  bioaugmentation 4/4/2008 480 1800.0 110.0 900.0
Post- bioaugmentation 11/12/09 <0.5 <0.51 <0.44 <0.5

All concentrations shown in µg/L.

 

Southeastern Florida Marina

Tequesta, Florida

Facility ID # 43-8731703

Subsequent to the removal of petroleum underground storage tanks (USTs), piping and surrounding soils for redevelopment, residual soil and ground water contamination at the site were treated with Petrox® bioremediation.  Petrox® was applied to the soil that was removed during the UST removals and to the ground water in the UST cavity.

Approximately 4,000 tons of soil were removed from the excavation and stockpiled on site for treatment.  The total BTEX concentrations in the excavated soil were up to 100 mg/kg.  Petrox® bioremediation was applied to the stockpiled soils.  In less than 90 days the petroleum was no longer detected in the soil and in the soil met the applicable Florida DEP standards.

Petrox® bioremediation was applied to the water in the former UST cavity to treat residual petroleum.  The proximity of the cavity to the Jupiter Sound indicated that the ground water was strongly influenced by infiltration from the Sound.  After less than 90 days post treatment, the water in the excavation also met the applicable Florida DEP standards.

 

Maximum Water Conc. Benzene Toluene Ethylbenzene Total Xylenes
Pre-treatment 1,960 5,140 1,860 18,340
90 days after treatment 3.7 BDL BDL BDL

All concentrations shown in µg/L. BDL= below detection limits.

 

Central Florida Gas Station

Petrox was applied to the ground water in an area around a single monitoring well that did not respond to another treatment as well as the rest of the plume.  A single 10-gallon application of Petrox® was sufficient to apply for site closure.

Sampling Date Benzene Toluene Ethylbenzene Total Xylenes
Pre- treatment 8/2/2007 11,100 1,250 1,260 5,040
Post-treatment 10/4/07 1,600 20.0 290. 840.
11/19/07 0.40 1.0 1.00 32.0

All concentrations shown in µg/L.

 

LNAPL Removal with Petrox

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Site Summary

Petrox® bioaugmentation was implemented to remediate fuel spilled at a railway in at Central, Ohio.  The impacted soil in the source area was excavated for off-site disposal.  The fuel, however, percolated through the fill into underlying soil.  The fuel migrated through the soil, seeped to the surface and formed a sheen on the water of an adjacent pond.  The LNAPL was removed and no longer visible in the pond and ground water monitoring seeps in less than 90 days after one application of Petrox®.

Geology and Hydrogeology

The spill occurred on a railroad embankment that is adjacent to a pond. The fill of the embankment is 2 to 3 feet thick.  The fill is on top of sandy clay deposits.  The slope of the embankment is very steep and slopes down to the pond.  After the fuel began to appear on the surface water, sumps were installed near the base of the slope and perched ground water was encountered at a few feet deep in the sumps.  The remediation was based on a conceptual model for the fuel seepage and migration.  Under the conceptual model, the fuel percolated through the fill to the native silty clay soil.  Once in the native soil, the fuel migrated through fractures as an LNAPL and seeped from weeps in the hillside.

Contamination

In immediate response to the fuel spill, the impacted ballast and fill were excavated and disposed off site.  Residual fuel remained in the soil below the excavation.  A hydrocarbon sheen was observed on the surface of the adjoining surface water approximately one month after the spill.  Containment booms were placed on the surface water and sumps were installed in the adjoining slope.  The LNAPL on ground water was as much as 0.2 feet thick in the sumps. The assumed area of the LNAPL was approximately 1,500 square feet.

Remediation

Petrox® was applied by injecting one drum (55-gallons) of a concentrated solution into the fill in the excavation area.  The Petrox® was allowed to flush through the impacted soil and follow the migration path of the fuel.  As the weather became seasonally dry, additional water was added to the excavation to support the microbial growth and to flush the microbes into the soil fractures.  During remediation the LNAPL thicknesses were measured in the sumps.  After each measurement the LNAPL was bailed from the sumps.

Results

Following Petrox® bioaugmentation the LNAPL thickness appeared to increase in some locations.  However, in 90 days the LNAPL was no longer present in the sumps and a sheen was no longer observed on the surface water.  The following table shows representative LNAPL thickness measurements (in feet).

Sump Number Pre-Treatment 30 Days Post Treatment 60 Days Post Treatment 90 Days Post Treatment
1 0.04 0.06 No LNAPL No LNAPL
10 0.15 0.12 0.08 No LNAPL
11 0.13 0.08 0.07 No LNAPL
15 0.12 0.10 0.18 No LNAPL

 

The treatment was successful in reducing the residual environmental impact of the fuel spill.  The treatment also verified the effectiveness of Petrox® bioaugmentation for petroleum LNAPL situations. 

Easy Bioremediation of Oil Surface Spills

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Petrox  bioremediation of oil surface spills reduces TPH accumulation in drainage ditches and maintenance areas. Using a simple manual sprayer, Petrox microbes applied to the soil surface begin bioremediation immediately.

The following chart shows the results of the application of 10 gallons of Petrox to petroleum-contaminanted soil in a drainage ditch. After about 60 days, the TPH concentration was reduced by 67% in one location and over 90% in three locations. The Petrox cost to treat 2,000 square feet was $200.

Shallow Soil Treatment Results

 

Bioremediation of BTEX at an Industrial Site in Florida

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Background

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.

industrial-site6

Conclusions

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.

In Situ Bioremediation of Petroleum LNAPL

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Background

High concentrations of petroleum in the subsurface can accumulate in a separate liquid phase that floats on the water table, which is referred to as light non-aqueous phase liquid (LNAPL). Investigation and characterization of the extent of separate phase petroleum is challenging. In turn, successful remediation, which depends on accurate and complete site characterization, can be equally challenging. In this case study Petrox® bioaugmentation was used to remove LNAPL and dissolved-phase petroleum to achieve No Further Action status.

Geology and Hydrogeology

The site is located in the Georgia Piedmont where the geology is characteristically weathered granite and saprolite. The petroleum was found in layers of interbedded clay, silt and sand. The first water was encountered at approximately 28 feet below ground surface. The hydraulic conductivity based on slug tests of the impacted zone was 10-4 to 10-5 cm/sec.

The ground water aquifer was naturally aerobic. Dissolved oxygen measurements taken from monitoring wells in the source area ranged from 1.9 to 2.1 mg/L. The oxidation-reduction potential (ORP) measured in the same wells ranged from 241 to 283 mv. The aerobic conditions were not typical of petroleum releases, but favored in situ bioremediation.

During the implementation of bioremediation, the region experienced a drought. The water table dropped below the bottom of some of the monitoring well screens for part of the period. Sampling results may have been affected during the drought, but normal ground water conditions were restored and maintained for the final two years of monitoring.

Contamination

The leaking underground storage tank (UST) was removed and a temporary high-vacuum dual phase extraction system was operated for one day in April 2007. Approximately 50 gallons of petroleum was removed by the high vacuum system. After operation of the high vacuum system was discontinued, the source area total benzene, toluene, ethyl benzene and xylene concentrations was more than 143,000 µg/L and 22 inches of separate phase petroleum was found in a monitoring well outside of the former UST cavity.

The remediation goals were to remove the separate phase product and reduce the dissolved phase BTEX concentrations to below in-stream water standards.

Remediation Approach and Results

The remediation approach was combination of in situ Petrox® bioremediation and periodic liquid phase bailing. It was believed that the petroleum was present in a thin layer, but represented itself as a thicker layer in the monitoring well that intersected the layer. The separate phase was bailed out when it was encountered during monitoring events.

Petrox® bioremediation was used to degrade the petroleum in the ground between the former UST cavity and the impacted down gradient monitoring wells. Petrox® was introduced into the contaminated ground water in three applications by injection through nine temporary well points surrounding the former UST location.

The first injection was 275 gallons of microbial slurry in August 2007. The dissolved phase BTEX concentration decreased by more than 60%. The contaminant concentrations continued to decrease for a year following the first injection. The BTEX concentration was reduced by 90% in that first year. A second injection of 110 gallons of Petrox was completed in September 2008. After one month the BTEX concentrations decreased by 50%. The following table summarizes the treatment and contaminant removal results.

groundwatersampling

The analysis of ground water samples for Pseudomonas sp. by plate count analysis showed the microbial population increased over background levels. The Petrox population maintained an effective level for bioremediation for 6 months to a year following each application.

The separate phase was reportedly no longer present in 2011 and the site received a No Further Action Status designation.

Conclusions

This project demonstrates the benefits of bioaugmentation for high concentrations of petroleum in ground water. Bioaugmentation delivers very high population of effective petroleum-degrading organisms that can be sustained for a long time. The microbes are compatible with bailing out accumulated separate phase from monitoring wells to accelerate the site closure. The total cost for microbes used to close this site was $8,000.