EHC-O®:  Oxygen Releasing Compounds for In-Situ Bioremediation of Petroleum Hydrocarbons
Fayaz Lakhwala, Adventus Americas, Inc., Union, NJ
Ravikumar Srirangam, Adventus Americas, Inc., Union, NJ
Jim Mueller, Adventus Americas Inc., Freeport, IL 
Alan G. Seech, The Adventus Group, Penticton BC

Bioremediation of Chlorinated Solvents in the Brunswick Shale of Southeast Pennsylvania
Kevin W. Frysinger, Environmental Standards, Valley Forge, PA 
Gerald L. Kirkpatrick, Environmental Standards, Valley Forge, PA                    

Microbial Ecology as an Indicator of Effectiveness of Sequential Chemical Oxidation-Bioremediation
Arati Kolhatkar, BP, Houston, TX                                           
Lyle Bruce, BP, Warrenville, IL
Paul Taylor, BP, Houston, TX
Rick Allison, Delta, Loveland, CO
Mark Nelson, Delta, Shoreview, MN
Jared Otto, Delta, Shoreview, MN

Field Evidence of Anaerobic Biodegradation of Benzene Coupled to Denitrification
Edward Sullivan, Whitman, East Brunswick, NJ
Eric C. Hince, P.G., Geovation Consultants, Inc., Florida, NY

Effect of Fe (III) Reduction in the Biodegradation of Chlorinated Ethenes
Na Wei, University of Illinois at Urbana-Champaign, Urbana, IL
Kevin T. Finneran, University of Illinois, at Urbana-Champaign, Urbana, IL

EHC-O®:  Oxygen Releasing Compounds for In-Situ Bioremediation of Petroleum Hydrocarbons

Fayaz Lakhwala, Adventus Americas, Inc. 1435 Morris Avenue, 2nd Flr., Union, NJ 07083, Tel: 908-688-8543, Fax: 908-688-8563, Email: Fayaz.Lakhwala@AdventusGroup.com
Ravikumar Srirangam, Adventus Americas, Inc. 1435 Morris Avenue, 2nd Flr., Union, NJ 07083, Tel: 908-688-8543, Fax: 908-688-8563, Email: Ravi.Srirangam@AdventusGroup.com
Jim Mueller, Adventus Americas Inc., 2871 W. Forest Road, Suite #2, Freeport, IL  61032, Phone: (815) 235.3503, Email: jim.mueller@adventusgroup.com
Alan G. Seech, the Adventus Group. 113-437 Martin Street Penticton BC V0H IN0 Email: Alan.Seech@AdventusGroup.com

Abstract EHC-O® is a buffered source of slow-release oxygen plus inorganic nutrients for accelerated bioremediation of soil, sediment and groundwater environments impacted by organic constituents amenable to aerobic biodegradation processes (e.g., petroleum hydrocarbons). EHC-O significantly stimulates the catabolic activity of the indigenous microflora, thereby accelerating the rate of contaminant removal. Installation techniques vary widely depending on the application. For example, the powder can be mixed with soil and placed at the bottom of an excavation where prior soil removal had been conducted. A slurry can be made and the mixture can be injected into the subsurface using techniques such as direct injection through Geoprobe rods or hydraulic fracturing. In addition, O-Sox™ canisters are available in various diameters for direct placement into existing or newly installed wells. The EHC-O O-Sox™ are advanced in their design and construction; they are simple to use and they represent a significant improvement over existing sock technologies.

Case Study 1. Groundwater at a site in Wisconsin, USA was impacted with petroleum-based volatile organic compounds (PVOCs) up to levels of 2,300 ppb. The groundwater table was approximately 5 ft bgs, and the impacts extended down to approximately 15 ft bgs. In August 2005, a total of 450 lbs of EHC-O were introduced into 9 injection points in the hot spot area. The concentration of the remaining PVOCs had also decreased significantly; the benzene concentration decreased by >99% (from 750 to 1.4 ppb) and the MTBE concentration decreased 88% (from 240 to 29 ppb). A second sampling event conducted 4 months following the injections indicated that benzene had decreased below the laboratory analytical detection limit and MTBE had decreased to 13 ppb.  The concentrations of all constituents reached below the State of Wisconsin’s groundwater ES. The site was recommended for closure within 4 months of switching from an alternative source of oxygen release compound to the EHC-O technology.

Case Study 2: Soil and groundwater at the former Feley Farms Site (Michigan, USA) was impacted by gasoline constituents that originated from former USTs.  The leaking tanks were removed in 1995; based on the reported petroleum-contaminated water seeping into the excavation hole along the surface of the bedrock during the tank removal process, groundwater monitoring was recommended. Following conventional remedial actions (including soil excavation, SVE, and groundwater pump-and-treat) benzene and gasoline constituents remained present in the groundwater at levels exceeding the Michigan Department of Environmental Quality’s regulatory limit of 5 ppb.  Approximately 4 months following EHC-O injection, the concentration of benzene in groundwater decreased by >99% in both monitoring wells One year post treatment monitoring showed that the concentration of benzene and other constituents remained below the analytical detection limits

Bioremediation of Chlorinated Solvents in the Brunswick Shale of Southeast Pennsylvania

Kevin W. Frysinger, PG., Environmental Standards, 1140 Valley Forge Road, Valley Forge, PA, 19482, USA, Tel: 610-935-5577, Fax: 610-935-5583, Email: kfrysinger@envstd.com
Gerald L. Kirkpatrick, CPG, Environmental Standards, 1140 Valley Forge Road, Valley Forge, PA, 19482, USA, Tel: 610-935-5577, Fax: 610-935-5583, Email: gkirkpatrick@envstd.com

A persistent chlorinated solvent plume was the target of voluntary bioremediation efforts at a fractured bedrock site in southeast Pennsylvania.  The history of the plume, and the hydrogeologic circumstances associated with designing an in-situ bioremediation remedy in this fractured bedrock aquifer are examined.  Additionally, findings of the pilot scale bioremediation program are also discussed. 

The site is located in the Triassic Age Newark Basin and is underlain by the Brunswick Shale of the Newark Supergroup and surrounded by intrusive diabase dikes and sills.  These rocks have low primary porosity and transmit groundwater via fractures and along weathered bedding planes.  Flow along these secondary features results in groundwater movement being controlled by local and regional topography, formation bedding, and regional groundwater use.  Shallow groundwater is affected by chlorinated solvents to a much higher degree than deeper groundwater at the site.  This indicates that a high degree of attenuation occurs, as shallow groundwater seeps into the deeper bedrock aquifer.  Additionally, the data suggest that shallow groundwater is in direct and continuous communication with the underlying bedrock aquifer; as a result, the aquifer was treated as a single unit, and the in situ groundwater remedy was designed with that conceptual flow system in mind. 

A six month pilot scale test using a patented soybean oil substrate was undertaken on July 29, 2008.  Approximately 1,800 gallons of diluted substrate solution was injected into the bedrock groundwater aquifer through three injection wells.  To evaluate the reaction of the aquifer to the amendment, monthly samples were collected in downgradient monitoring wells.

This paper will provide an assessment of project design, substrate injection, and evaluate issues associated with practical aspects of undertaking injection programs in a fractured bedrock aquifer.

Microbial Ecology as an Indicator of Effectiveness of Sequential Chemical Oxidation-Bioremediation

Arati Kolhatkar, BP, 501 Westlake Blvd., Houston, TX 77079, USA, Tel: 281-366-5596, Fax: 281-366 7094, Email: arati.kolhatkar@bp.com
Lyle Bruce, BP, 28100 Torch Parkway, Warrenville, IL 60555, USA, Tel: 630-836-7104, Fax: 630-234-8652, Email: brucelg@bp.com
Paul Taylor, BP, 501 Westlake Blvd., Houston, TX 77079, USA, Tel: 281-366-6920, Fax: 281-366-7094, Email: paul.taylor2@bp.com
Rick Allison, Delta, 1343 South Garfield Avenue, Loveland, CO 80537, USA, Tel: 970-292 1885, Email: rallison@deltaenv.com
Mark Nelson, Delta, 5910 Rice Creek Pkwy, MN 55422, USA, Tel:  651-697-5235, Fax: 651-639-9473, Email: mdnelson@deltaenv.com
Jared Otto, Delta, 5910 Rice Creek Parkway, Suite 100, Shoreview, MN 55126, USA, Tel: 651-697-5232, Fax: 651-639-9473, Email: jotto@deltaenv.com

Remediation strategies frequently employ multiple technologies that follow sequentially to achieve site clean-up goals.  ISCO (in-situ chemical oxidation) followed by natural bioremediation is a commonly-recommended treatment train.  It may be erroneously assumed that by reducing the high-concentration hydrocarbons, ISCO application creates favorable conditions for bioremediation.  However, at two sites, persulfate (ISCO agent) application was detrimental to microbial ecology and it took several months to regain or exceed its original health. 

Effectiveness and effect of persulfate application was evaluated by monitoring contaminant of concern (BTEX), geochemistry, and phospholipids fatty acids (PLFA), a main component of the microbial membrane.  PLFA analysis provides a powerful tool for assessing microbial responses to changes in their environment and was used to study the effect of persulfate application on site microbial ecology.  At Site A, order of magnitude reduction in total biomass was observed 1-month after persulfate injection.  Due to multiple injections at Site B, although it was difficult to deduce the effect of 1^st persulfate application on microbial ecology, a more than 50% reduction in total biomass was observed about 40 days after 3^rd injection.  At 2-months and 4-months after last application at Site A and B respectively, microbial population at Site A is recovering and microbial ecology at Site B got a boost of more than 100%. One explanation is that the ISCO agents are toxic to the microbes but given sufficient time, as the ‘toxic’ plume travels ahead or is attenuated, microbes recover and sometimes exceed the original population.  In case of persulfate, increase in microbial population can be attributed to an increased electron acceptor pool (sulfate) that is a by-product of persulfate chemistry. 

This study demonstrated that if an ISCO-bioremediation treatment train is employed at a site, then bioremediation effectiveness monitoring is recommended only after ensuring that the microbial ecology has recovered. 

Field Evidence of Anaerobic Biodegradation of Benzene Coupled to Denitrification

Edward Sullivan, P.G., Whitman, 116 Tices Lane, Unit B-1, East Brunswick, NJ 08816, Tel: 732-390-5858, Fax: 732-390-9496, Email: esullivan@whitmanco.com
Eric C. Hince, P.G., Geovation Consultants, Inc., 468 Route 17A, Florida, NY, 10021, Tel: 845-651-4141, Fax: 845-651-0040, Email: echince@geovation.com 

Recent evidence has shown that BTEX compounds can biodegrade under anaerobic conditions utilizing a number of electron acceptors including nitrate, bioavailable ferric iron and sulfate.  Studies by Coates, Bender and Hince have shown that BTEX compounds including benzene will biodegrade under denitrifying conditions, contrary to the long held conventional wisdom that benzene is recalcitrant under anaerobic conditions.  At a former fuel oil storage facility in New Jersey, a denitrification based bioremediation (DBB) approach was used to remediate residual BTEX contamination.  A large volume of soil had been excavated at the site to remove source materials related to historic heating oil and gasoline releases.  However, because the excavation extended well below the water table to the top of an uneven bedrock surface, some residual impacted soil above the bedrock could not be removed.  Membrane Interface Probe (MIP) borings confirmed the presence of residual contamination in the interval 2-3 feet above the bedrock.  As a result, BTEX contamination was detected in four monitoring wells installed after the excavation at the site.  The highest total BTEX (673 µg/L) and benzene (199 µg/L) concentrations were detected in well MW-5.  The DBB treatment area at the site encompassed approximately 35,000 square feet and targeted the materials just above the bedrock.  Remedial injections of a nitrate releasing compound (N-Blend) and sodium percarbonate were conducted using a total of 32 injection points along four lines aligned perpendicular to ground water flow.  A total of 1,000 gallons of N-blend and 200 gallons of percarbonate solution were injected during two injection events spaced five months apart.  Two years after the injections, total BTEX and benzene concentrations in the four impacted monitoring wells were reduced by 99% to 100%.  At MW-5, concentrations of benzene, other BTEX compounds and tentatively identified compounds (TICs) were all non-detect, two years post-treatment.  Quantitative fluorescence in-situ hybridization (“FISH”) assays indicated that the proportion of Pseudomonas-related Gammaproteobacteria and Betaproteobacteria, which include petroleum degrading denitrifiers, increased significantly in MW-5 in response to the DBB treatment.  It is believed that this is among the first field scale projects to demonstrate successful anaerobic benzene biodegradation coupled to denitrification.

Effect of Fe (III) Reduction in the  Biodegradation of Chlorinated Ethenes

Student Presenter 

Na Wei, University of Illinois, at Urbana-Champaign, Urbana, IL, Email: nawei2@illinois.edu
Kevin T. Finneran, University of Illinois, at Urbana-Champaign, Urbana, IL, Email: finneran@illinois.edu

Chlorinated ethenes are widespread aquifer contaminants in the United States. Trichloroethene (TCE) is among the most prevalent groundwater contaminants due to its common use as organic solvents in industry and dry cleaning. TCE bioremediation via reductive dechlorination is one of the most prevalent strategies. Under anaerobic conditions, which is typical in contaminated subsurface environment, TCE has been found to undergo reductive dechlorination and be sequentially transformed to less chlorinated intermediates cis-dichloroethene (cis-DCE) and vinyl chloride (VC), or under certain conditions to nontoxic product ethene. But in most cases, the transformation of cis-DCE and VC is the rate limiting step, leading to the accumulation of cis-DCE and VC in contaminated sites, especially when there are alternative electron acceptors competing for electron donors. Fe (III) is the predominant electron acceptors in many aquifer and freshwater sediments, and Fe(III) reduction is often considered a competitive process. However, the actual role of Fe(III) in dechlorination is unclear and has not been well studied.

In this study, we have been investigating TCE and VC degradation in microcosm incubations with contaminated aquifer sediments. Complete TCE reduction to ethene with concomitant Fe (III) reduction has been quantified with acetate as sole electron donor. In the incubations with both TCE/VC and Fe(III) added as electron acceptor, TCE/VC was reduced to ethene with simultaneous Fe(III) reduction. In the incubations added with TCE/VC, Fe(III) and sulfate, the reduction of all the electron acceptors was concurrent. 16S rDNA based molecular analyses revealed that the microbial communities in the sediment microcosms degrading TCE/VC to ethene did not have Dehalococcoides present.  Liquid enrichments have been set up with the material from active sediment microcosms, and concurrent Fe(III) reduction and dechlorination were also observed. These results are unique, and they suggest that alternate electron acceptors such as Fe(III) and/or sulfate may not inhibit, but rather, may stimulate, degradation of chlorinated solvents. Further studies are being carried out to investigate kinetics and mechanism of transformation of chlorinated ethenes under iron-reducing conditions, and to better understand the role of Fe(III) in dechlorination. This study will provide insight to better understand the fate of chlorinated ethenes in natural attenuation and to help develop novel approaches for in situ bioremediation of chlorinated solvents.

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