January 8, 2018

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Geosyntec and SiREM Partner on Enhanced Biological Reduction Article Published in the Remediation Journal

Geosyntec's Melissa Schmitt (Washington), Srinivasa Varadhan, and Eric Suchomel (California) partnered with SiREM employees Sandra Dworatzek and Jennifer Webb (Ontario) on an article entitled "Optimization and validation of enhanced biological reduction of 1,2,3-trichloropropane in groundwater" that was published in Remediation Journal on pages 17–25, Volume 28, Issue 1, Winter 2017.

Melissa Schmitt is a Principal Environmental Engineer based in Washington State with more than 10 years of professional experience focused on contaminated site assessment, remediation, and regulatory compliance. She specializes in helping her clients perform site assessments and develop closure strategies, as well as design, implement, and optimize soil and groundwater remediation projects at their complex sites.

Eric Suchomel is a Principal Environmental Engineer based in California with more than 10 years of professional experience focused on remedial program management, site investigation and characterization, feasibility study preparation, remedial system design and implementation, remedial system optimization, and litigation technical support.

Srinivasa Varadhan is a Project Engineer based in California with more than seven years of professional experience focused on contaminated sediments, soil and groundwater remediation, and Environmental Health and Safety, expertise in enhanced reductive dehalogenation, biological treatment processes, in-situ chemical
oxidation, and treatment system process design.

The Remediation Journal is known as the journal of cleanup costs, technologies, and techniques and it has been honored by industry peers with an Award for Publication Excellence at the 2016 APEX Awards.

SiREM was founded in 2002 to provide the highest quality testing services and remediation products combined with unparalleled technical support to increase remediation effectiveness, decrease remediation costs and provide peace of mind during field implementation. Their focus is the remediation of chlorinated solvents, metals, petroleum hydrocarbons and other recalcitrant contaminants in soil, sediment and groundwater.


Laboratory and field demonstration studies were conducted to assess the efficacy of enhanced biological reduction of 1,2,3-trichloropropane (TCP) in groundwater. Laboratory studies evaluated the effects of pH and initial TCP concentrations on TCP reduction and the activity of a microbial inoculum containing Dehalogenimonas (Dhg). Laboratory results showed successful reduction at a pH of 5 to 9 with optimal reduction at 7 to 9 and at initial TCP concentrations ranging from 10 to over 10,000 micrograms per liter (μg/L). Based on findings from the laboratory study, the effects of TCP concentration, geochemical conditions, and amendment concentration on bioremediation efficacy were investigated during a field demonstration at a site with relatively low initial concentrations of TCP (< 2 μg/L). The field demonstration included injection of emulsified vegetable oil (EVO) and lactate as a carbon substrate for biostimulation, followed by bioaugmentation using the microbial inoculum containing Dhg. Post-injection performance monitoring demonstrated reduction of TCP to below laboratory detection limits (< 0.005 μg/L) after an initial lag period of approximately six months following injections. TCP reduction was accompanied by generation of the degradation byproduct propene. A marginal increase in TCP concentrations, potentially due to an influx of upgradient aerobic groundwater containing TCP, was observed eight months after injections thereby demonstrating the sensitivity of this bioaugmentation application to changes in geochemical parameters. Despite this marginal increase, performance monitoring results indicate continued TCP biodegradation 15 months after implementation of the injection program. This demonstration suggests that enhanced biodegradation of TCP by combining biostimulation and bioaugmentation may be a promising solution to the challenges associated with remediation of TCP, even when present at low part per billion concentrations in groundwater.

More Information

Learn more about the article at: http://onlinelibrary.wiley.com/doi/10.1002/rem.21539/full.
Learn more about SIREM at: http://www.siremlab.com/about-us/.
For consultation regarding biological reduction of 1,2,3-trichloropropane, contact Melissa Schmitt at This email address is being protected from spambots. You need JavaScript enabled to view it..
Learn more about Melissa Schmitt at: https://www.geosyntec.com/people/melissa-schmitt  
Learn more about Eric Suchomel at: https://www.geosyntec.com/people/eric-suchomel
Learn more about Srinivasa Varadhan at: https://www.linkedin.com/in/srinivasa-varadhan-bb2b1917/