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Overcoming TCE Cometabolism Rate Limits

Aerobic cometabolism of TCE may be limited by the potential microbial toxicity of by products or by product metabolic repression.  An independent comparison of induced cometabolism using soluble methane and CL-Out bioaugmentation showed that CL-Out bioaugmentation removed more TCE.  The TCE removal rate by CL-Out when supplemented with an oxygen source was a steady rate that continued past apparent limits of induced cometabolism.  The significant difference may be in that the population of beneficial microbes that can be added is much higher than the population level that may be achieved through biostimulation.  For a brief summary of the study follow this link Overcoming TCE Metabolic Limits.

Surface Spills to Deep Subsurface Success With Petrox Bioremediation

Petrox bioremediation is used to remove petroleum contamination from soil and water under many different conditions.  From surface spills to deep soil and ground water contamination, Petrox has successfully removed the contamination and environmental risk.  This summary of case studies demonstrates the applicability of Petrox bioremediation to the full range and life cycle of petroleum spills. Click here to view the document.

 

Bioremediation of Industrial Fill

Historical industrial sites often have deposits of fill material containing a wide range of organic contaminants.   Perched ground water  present in the base of the fill is usually impacted by the contaminants and may provide a mechanism for off-property migration of the contaminants.  The organic contaminants are wide spread throughout the fill without a well defined source area.  Cost-effective remediation is difficult with this combination of conditions.

Bioaugmentation with CL-Out or Petrox can remove the contaminants from the fill and perched water by destruction in place.  The organisms in CL-Out and Petrox can metabolize a wide-range of organic chemicals at concentrations from separate-phase layers to part per trillion levels.  Soil and ground water contaminants are addressed simultaneously though injection of the microbes without disturbing the  site operations.

The following table shows typical results from a single application of Petrox to contaminated soil and perched ground water on July 10, 2011.  The remediation progress was tracked by ground water monitoring because it was the easiest sampling method once wells were in place.Industrial Fill TreatmentThe results show that within 30 days the contaminant concentrations in perched water were reduced by 50%.  After 60 days there was slight rebound in come of the contaminants, showing that more soil treatment may be necessary if lower cleanup goals needed to be maintained.

 

 

Florida Site Closures With One Petrox Application

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.

 

Bioremediation of BTEX at an Industrial Site in Florida

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.