Sulfolane is an emerging contaminant of concern for potential environmental impact to ground water in Alberta. CL Solutions recently completed laboratory bench-scale testing that showed the Petrox organisms can efficiently degrade sulfolane. Under laboratory conditions Petrox organisms metabolized sulfolane at a minimum rate of 33 ug/L/day. Further lab tests are under way and field scale implementation may proceed in the Summer of 2017.
Petrox microbes were added to excavated petroleum-contaminated soil to accelerate the degradation of DRO and ERO total petroleum hydrocarbons. Petrox was added by spraying the surface of the soil with a hydrated Petrox solution. The microbes were mixed into the soil using a tractor-mounted disc tiller.
After approximately 60 days, soil samples were taken for testing. The soils showed 90% to 99% petroleum removal. The following chart shows the range of DRO and ERO concentrations before and after Petrox treatment.
Petrox bioremediation accelerates the removal of naphthalene and isomers of methylnaphthalene. These petroleum compounds are often slow to remediate due to their low volatility and strong affinity for absorption onto soil particles. The remediation rate of these compounds is slower than BTEX compounds. They often also rebound as the absorbed phase solubilizes following removal of the compound from ground water to reestablish phase equilibrium. Petrox bioremediation accelerates the remediation of these compounds by a combination of metabolizing the dissolved phase and a biosurfactant effect that strips the compound from soil to make it available for metabolism.
For example, Petrox achieved more than 90% removal of these compound in less than 9 months at a site of a former underground storage tank (UST) in Florida. After the UST and surrounding contaminated soil were removed, the residual BTEX compounds were treated by chemical oxidation. The chemical oxidation, however, did not remove the naphthalene and methylnaphthalene isomers. Petrox was applied to the ground water in and around the former UST cavity.
Nine months after the Petrox application the following reductions in concentrations were achieved. The concentrations are the average of four ground water sampling locations.
Naphthalene – 367 ug/L reduced to 18 ug/L, 95% removal.
1 Methylnaphthalene – 255 ug/L reduced to 33 ug/L, 87% removal.
2 Methylnaphthalene – 400 ug/L reduced to 30 ug/L, 93% removal.
The Petrox was injected into the ground through a continuous low-volume injection system. This application method did not impact the use of the property or require major construction. The application was also far less costly than alternatives.
The greatest benefit was the relatively rapid removal of difficult contaminants. Click here and here to view cases studies of naphthalene bioremediation case studies. Use the search bar to find even more case studies of naphthalene bioremediation.
Bioaugmentation results can be accelerated and amplified by soil mixing to improve distribution and contact. The equipment shown in this example was used to blend Petrox with contaminated soil to a depth of 10 feet.
For a brief summary of the basics of petroleum bioremediation follow this link Basics of Petroleum Bioremediation