Fast BTEX and Methylnaphthalene Bioremediation

Petrox Petrox and Methylnaphthalene Bioremediation Site Summary

Petrox micorbes accelerated BTEX and methylnaphthalene bioremediation at a former fueling station in Florida.  After a leaking tank underground storage tank (UST) was removed,  the consultants injected Petrox micorbes into the groundwater. A temporary well showed high concentrations of BTEX, methylnaphthalene isomers, and total recoverable petroleum hydrocarbons (TRPH) in the former tank location.  A permanent monitoring point replaced the temporary well. Since the contaminants were not detected outside of the UST cavity, the treatment focused on the cavity and its proximity. The consultant injected Petrox  into the ground water through 12 direct-push injection points in and around the UST cavity. They used approximately 10 gallons of Petrox solution at each of the injection points in August 2001. After one injection of Petrox, petroleum hydrocarbons concentrations decreased below detection levels in the UST cavity.  Please refer to the table below for the ground water monitoring results.

Persistence in Soil and Low Ground Water Concentrations

Methylnaphthalene and naphthalene persist in soil after other volatile components of fuels are gone.  The persistence comes from to their relatively high affinity for adsorption to soil and relatively low water solubility.  These factors account for the common rebound of ground water concentrations. Despite high concentrations of naphthalene and methylnaphthalene in soil near the ground water table, often the dissolved  concentration in the ground water is very low.  The accumulation of these compounds at the water table causes a problem for remediation.  Frequently after ground water remediation, seasonal fluctuation of the water table through the contaminated vadose zone recharges the concentrations of these compounds.  This results in seasonal fluctuation in the ground water concentrations.

Methylnaphthalene Metabolism

The microbes in Petrox  accelerate the remediation because they product an extracellular biosurfactant that desorbs the methylnaphthalene to make it available for extraction or for in situ bioremediation.  At this site, the contaminated soil was removed to the water table, so concentrations did not rebound after the initial ground water remediation.  At other sites where Petrox bioremediation addressed methylnaphthalene or naphthalene, the consultant combined bioremediation with extraction.  The combined technologies removed the contamination flushed from the soil in addition to the bioremediation.  Click here to view case studies from other sites.

Methylnaphthalene Bioremediation


Nitrate and Perchlorate Bioremediation in Ground Water

In Situ Nitrate and Perchlorate Bioremediation Eliminated Pump and Treat and Ion-Exhange Treatment Cost 

Site closure reached in less than half the projected time and cost

CL-Out® bioremediation was implemented at a confidential manufacturing site to remediate nitrate and perchlorate concentrations in soil and ground water.  The consultant installed a pump and treatment system that was operated for several years in immediate response to the discovery of contamination. While perchlorate was  the primary contaminant,  the ion-exchange resin became quickly saturated with nitrate, which was present at much higher concentrations than the perchlorate.  After reviewof various options andcompletion ofabench-scale test, the consultant implemented in situ CL-Out bioremediation to reduce the on-going cost of ground water extraction and treatment.

One of the key factors in CL-Out® cometabolism of perchlorate at this site was that CL-Out® organisms were able to reduce sequentially the oxygen and nitrate prior to perchlorate. The initial nitrate concentrations were  much higher than the perchlorate concentrations and pre-maturely saturated the ion-exchange resin. The perchlorate concentration did not decrease until the nitrate concentration decreased to less than the perchlorate concentration. One of the benefits of the CL-Out® organisms was this ability to utilize these different electron acceptors.

The initial application of CL-Out to the soil reduced the perchlorate source concentration.  After eight months of ground water bioremediation, the perchlorate concentration in the unconsolidated aquifer decreased from 128 mg/L to 3.4 mg/L immediately down gradient of the source area and from 220 mg/L to 39 mg/L farther down gradient.

Simultaneously, the CL-Out® microbes also removed the nitrate. Down gradient of the source area the nitrate concentration decreased from 105 mg/L to <1.0 mg/L.  Farther down gradient the nitrate concentration decreased from 200 mg/L to 5 mg/L.

The in situ nitrate and perchlorate bioremediation provided immediate risk reduction and mitigated potential off-site migration. The bioremediation contaminant levels to the remediation target in 3 years.  Bioremediation saved 5 years of projected treatment time and millions of dollars in OM & M costs.  The owner sold the property without environmental impairment upon completion of bioremediation.

Project Consultant Received Green Leadership Award

The Massachusetts Department of Environmental Protection awarded Irwin Engineering of Natick, Massachusetts the 2016 Greener Cleanup Leadership Award for the innovative in situ bioremediation of perchorate contamination of soil and ground water at the Concord Road Site in Billerica, Massachusetts. The award honors LSPs and their clients for promoting greener cleanup principles and practices to reduce the overall net environmental footprint of hazardous waste site cleanup response actions under the Massachusetts Contingency Plan.

Click here for more information about CL-Out bioremediation.




Bioremediation of Phthalates

Bioremediation of phthalatescan reduce risks to human health and the environment.  Phthalates are a  a family of common industrial chemicals used in plastics and other consume products.  Phthalates can damage the liver, kidneys, lungs and reproductive system.  Petrox microbes can remove these contaminants from water or soil to reduce potential exposure to these risks.

Petrox bioremediation of phthalates has been demonstrated in field and laboratory studies to remove phthalates from soil and ground water.  Field application of Petrox bioremediation reduced bis(2-ethylhexyl)phthalate (BEP) concentrations from 650 ppm to 397  ppm in soil and 300 to 39 ppb in ground water at a site in Rochester, New York.  At the same site di-n-octylphthalate (DOP) in soil was reduced from 7.5 to 1.9 ppm. Click here to view the case study.

PCE Aerobic Bioremediation by Key-hole Source Removal

CL-Out aerobic PCE bioremediation in a keyhole treatmentreduced the mass of contamination near the source and down gradient concentrations in the plume.  At a former manufacturing facility in Ohio the concentration of PCE near the source was over 100,000 ug/L.  Down gradient of the source the PCE concentrations were less than 10% of the source concentration.  Aggressive treatment in the source area reduced the source concentration and in the down gradient plume.

Source area concentrations decreased as follows after one treatment with CL-Out bioremediation:

  • PCE decreased from 120,000 to 12 ug/L.
  • TCE decreased from 2,000 to 12 ug/L
  • Cis 1,2-DCE decreased from 9,500 to 8,100 ug/L.
  • Vinyl chloride, however, increased from 1,200 to 22,000 ug/L.

The vinyl chloride increased as the aggressive cometabolic treatment stimulated  incomplete reductive dechlorination by other naturally occuring organisms.

Down gradient from the source, the concentrations decreased with slight to no increase in daughter products.  The  down gradient plume had the following results:

  • PCE decreased from 5,000 to 1,600 ug/L.
  • TCE decreased from 43 ug/L to BDL.
  • Cis 1,2-DCE decreased from 140 to 23 ug/L.
  • Vinyl chloride  was not detected before or after treatment.

Keyhole treatment was a cost effective approach to reducing the mass of contamination in a ground water plume by focusing aggressive treatment on the source area.  Concentrations in the rest of the plume decreased as the microbes and treated water dispersed through the plume.

Aerobic PCE Bioremediation By Cometabolism

CL-Out is a consortium selected for aerobic PCE bioremediation.  CL-Out cometabolizes PCE by growing on a simple sugar and producing a metabolic enzyme to degrade PCE.  The microbes produce a dioxygenase enzyme that breaks the carbon bond in PCE.  This reaction eliminates the biproducts of reductive dechlorination.  Also, the synergistic effect of the CL-Out consortium cometabolizes the full suite of chloroethenes and chloroethanes.

Click here to learn more about CL-Out bioremediation.

TCE and 1,1,1-TCA Bioremediation at Indiana Industrial Site

TCE and 1,1,1-TCA bioremediation by CL-Out organisms reduced contaminant concentrations  in ground water under a drum storage area at a central Indiana industrial site.  After  three  monthly applications  of CL-Out microbes, the in situ treatment reduced total maximum CVOC concentrations from 102 mg/L to 3 mg/L in less than 6 months. Click here to view the complete case study.