PCB Treatment Technologies:State of the Science

Greg Gervais, P.E., ChiefEPA Superfund HQ – Technology Assessment Branch

John McKernan, Sc.D., CIHORD Engineering Technical Support Center

September 18, 2014

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Key Questions

• Current PCBs treatment research status within EPA

• New/emerging PCBs treatment technologies used at sites

• Approval process for implementing new emerging technologies at Superfund sites

• Opportunities to tour EPA facilities with research on PCBs treatment

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Treatment and Superfund

• RCRA Treatment Definition– Any process that changes the physical, chemical, or

biological characteristics of a waste to minimize its threat to the environment

• Superfund Mandate:– Use of alternative treatment technologies to the

extent practicable– Preference for remedies that employ treatment that

permanently and significantly reduces the toxicity, mobility or volume of hazardous substances

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General Modes of Treatment• Immobilize

– Larger volumes of waste– Difficult to modify or destroy– Ex. ‘warm spot’ contaminated soil or sediments

• Modify– Smaller volumes of waste– Chemical, biological or physical process can change contaminant to

less toxic/mobile constituent; separation/concentration– Ex. ‘hot spot’ recovery of spilled PCBs waste oil

• Destroy– Smaller volumes of waste– Difficult to modify– Ex. ‘hot spot’ excavation and incineration of small soil volumes with

very high concentrations

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Projects with PCBs Treatment Technologies

• First, a recap on PCBs remediation to date at SF sites– Combinations of containment and source

treatment– Containment usually on site– Treatment often a thermal-based technology like

incineration or desorption– Treatment focused on strong/highly concentrated

source materials (like PCBs in oil)

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Historic Sites with PCBs Remediation or Treatment

• R1 Housatonic River – bioremediation tech evaluation• R2 Passaic River – bioremediation pilot study• R3 American Cyanamid – thermal remediation• R3 Lower Darby Creek – Landfill cover design• R3 Washington Navy Yard – analysis of PCBs in

sediment• R5 Fox River• R7 Die Casting Site – chemical oxidation for mixed

liquid waste

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Key PCBs Characteristics at Allied Site

• Binding properties of PCBs to environmental organics– Hydrophobic

• Low concentrations in site groundwater– PCBs and similar chemicals bond strongly to organics– Observed to migrate deeper into ‘pores’ of organics over

time• Challenges/site conditions due to binding properties

– Disassociating PCBs from organics = energy intensive– Energy intensive, High cost– Treatment of media with low concentration is not

substantially different than high concentration• Very low groundwater flow rate in site waste similar to

performance specs of an engineered system (10-7 cm/s)

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Status of PCBs Research in EPA ORD• PCBs remediation and treatment research in ORD

– Limited PCBs research being conducted for sediments– Research linked to technical support requests from

either EPA Regions, OSWER or GLNPO– Research being conducted by contractors, not in EPA

facilities– Historic soil research on PCBs, none ongoing

• PCBs remediation Technology Assessment– Bioremediation – 2013– OSWER 2010 on POP’s

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Treatment and Containment Alternatives to ‘Capping In Place’

• Solidification/Stabilization• Thermal Desorption• Bioremediation• Phytoremediation• Incineration• Chemical Treatment• Other methods

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Solidification/StabilizationEx situ and in situ methods

Pros• No excavation needed for in situ methods• Beneficial reuse (fly ash)

Cons• Energetically costly• Doesn’t degrade PCBs remove contamination• Potential for leaching• Long-term monitoring needed• Sensitive to moisture, pH, and organic

content

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Thermal DesorptionPros

• Effective over a wide range of contaminants• In situ techniques eliminate the need for excavation

Cons• Energy-intensive

and creates manywaste streams

• Ineffective atseparatinginorganics fromcontaminatedmedia

• Best suited to strong,small sources

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Thermal Desorption (cont’d…)

• On site thermal treatment– In-situ– Ex-situ

• Requires excavation first• Thermal desorption in concrete kiln-type equipment or

above ground version of in-situ thermal conduction

• Off site thermal treatment– Requires excavation and hauling first– (Very) few permitted facilities

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Thermal Desorption (cont’d…)

• In-situ thermal desorption– On site treatment– Boil-capture-destroy w/ heaters in the ground– Best for high concentrations over small area

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Courtesy: Terratherm

In-Situ Thermal Desorption• Ex. Pfizer’s Upjohn-Pharmacia RCRA site (North

Haven, CT)– 80 acre former specialty chemicals manufacturing facility– Part of $140M corrective action, with capping and water

treatment– Thermal via In Situ Thermal Desorption for < 3 acres,

focus on non-aqueous phase source liquids (“DNAPL”)– Heating ground up to 340 °C to boil PCBs, destroy in

flameless thermal oxidizer air treatment unit on site– 138,000 kg of DNAPL,15-30 feet below ground, 15%

VOCs, 80% SVOCs, 1% to 5% PCBs (i.e., 10,000 to 50,000 ppm PCBs)

Source treatment with containment

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• http://www.cluin.info/greenremediation/subtab_d37.cfm

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BioremediationPros

• Can be done onsite (no transport)• Uses natural systems to remediate chemicals • Lower energy

Cons• Still must excavate• Tends to be more effective at higher concentrations than at Allied• Since it’s a biological system, efficacy varies widely• Limited applicability to Persistent Organic Pollutants like PCBs• Cannot meet clearance levels in reasonable amount of time (likely need

decades)

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Bioremediation (cont’d…)• (some) Academic and vendor R&D• Difficult to find/deploy/grow microbe population to

degrade PCBs– Evidence does not support degradation of all PCB congeners nor

can one microbe degrade most of them• Bigger PCB molecules tougher for microbes to degrade• Very slow processes• Dependent on microbes being in contact with

PCBs tougher to deploy in-situ• Limited pilot studies…limited documented success• No full scale application on PCBs with documented success

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PhytoremediationPros

• Can be done onsite (no transport)• Uses natural systems to remediate chemicals (plant processes) • Lower energy

Cons• Limited applicability to Persistent Organic Pollutants like PCBs (possibly

susceptible to Rhizodegradation…not the 4 other Phytotechnologies)• Not effective beyond plant root zone (i.e., typically less than 1 ft deep)• Even if rhizodegradation occurs, cannot meet clearance levels in

reasonable amount of time (likely need decades)

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IncinerationPros

• Can be done onsite (no transport)• Highly effective

Cons• Excavation• Energetically costly• Water content

may increase energyinput needed

• Metals limit applicability• Produces residuals• Permitting• Public Opposition

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Chemical Treatment –Hydrogen Reduction

Pros

• Work done onsite• Highly effective• Contaminants to fuels

Cons

• ‘Resistive’ soils difficult• Excavation a must• High energy inputs, H2

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Chemical Treatment –Solvent Extraction and Chemical Dehalogenation

Pros

• Work done onsite• Low energy input

Cons

• Soils with high organiccontent difficult

• Excavation a must• Does not degrade contaminants• Produces residuals

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Other Methods -Oxidation and Vitrification

Pros• Effective over a wide range of contaminants• Oxidation – reduces contaminants to stable, oxidized forms• Vitrification – encapsulates contaminants permanently

Cons

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• Oxidation• Not targeted to PCBs – oxidizes everything• Requires hazardous oxidizers• Creates air emissions• Cost effective?

• Vitrification• Energy intensive • Creates air emissions - may emit PCBs vapors• Cost effective?

Technology Summary

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Alternative Technology Could Remediate PCBs from Allied Paper Landfill Successfully?

Appropriateness for Allied Paper Landfill? Time to Implement

Solidification/ Stabilization Yes Low 5 – 10 yrs

Thermal Desorption Yes Low Decades

Bioremediation/ Phytoremediation No n/a n/a

Vitrification Yes Low Decades

Incineration Yes Low Decades

Hydrogen Reduction No n/a n/a

Solvent Extraction/Chemical Dehalogenation No n/a n/a

EPA’s Technology Approval Process

• No technology-specific certification, licensing or approval process for use on SF sites

• Screening and selection based on site-specific appropriateness, comparison to other alternatives

• EPA Regional Office makes selection as part of cleanup decision making

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Possible PCBs Treatment Technology Research Facilities to Tour

• PCBs treatment research conducted at contractor labs, not in EPA facilities

• Research on reactive caps, bioremediation at sediments sites– EPA contractor test facility in Ohio– On actual SF site(s) in Northeastern US

• ISTT site remediation for PCBs, DNAPL, other contaminants– Upjohn Pharmacia site in CT

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Supplemental Information• Commercial disposers (EPA website, 2011):

http://www.epa.gov/epawaste/hazard/tsd/pcbs/pubs/stordisp.htm

• Cost data: EPA (1997). Management of Polychlorinated Biphenyls in the United States. Office of Pollution Prevention and Toxics, Washington, DC. Accessed on 9/2/2014. http://www.chem.unep.ch/POPs/indxhtms/cspcb05.html

• CLU-IN Polychlorinated Biphenyls (PCBs) Overviewhttp://www.cluin.org/contaminantfocus/default.focus/sec/Polychlorinated_Biphenyls_(PCBs)/cat/Overview/

• Engineering Issue: Technology Alternatives for the Remediation of PCB Contaminated Soils and Sediments. U.S. Environmental Protection Agency, Washington, DC, EPA/600/S-13/079, 2013. http://nepis.epa.gov/Adobe/PDF/P100GJNO.pdf

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Thank You!Greg GervaisEPA Superfund Headquarters703-603-0690Gervais.Gregory@epa.govwww.epa.gov/superfundwww.CluIn.org

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John McKernanEPA, Engineering Technical Support Center513-569-7415McKernan.John@epa.govhttp://www.epa.gov/nrmrl/lrpcd/etsc/