Perchlorate Remediation Receives Greener Cleanup Leadership Award

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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.

In addition to implementing best practices, Irwin Engineers was able to close the site at least 5 years sooner and saving their client over $5 million. The site cleanup achieved residential soil standards without site use limitations and achieved ground water levels protective of drinking water.

Land Farming Application Reduces TPH by 90% to 99%

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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.  photo-2              photo-1

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.

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Soil Mixing to Improve Distribution of Microbial Solution

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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.

Soil Mixing Equipment to Improve Microbial Solution Distribution

Soil Mixing Equipment to Improve Microbial Solution Distribution

Click here to view a short video of soil mixing.

The Basics of Petroleum Bioremediation

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For a brief summary of the basics of petroleum bioremediation follow this link Basics of Petroleum Bioremediation

Overcoming TCE Cometabolism Rate Limits

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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.