Optimizing In Situ Bioremediation of Chlorinated Ethenes in British Columbia s Groundwater Phil Dennis SiREM SMART Remediation Vancouver, ON February 11, 2016 SMART is Powered by: www.vertexenvironmental.ca
Optimizing in situ Bioremediation of Chlorinated Ethenes in British Columbia s Groundwater Phil Dennis, Peter Dollar, Jeff Roberts, Sandra Dworatzek Smart Remediation, Vancouver, BC February 11, 2016 SiREM Major Service Areas Remediation Testing Characterization/Monitoring Molecular Testing Bioaugmentation Cultures Passive Samplers for Vapour and Pore Water 1
FUNDAMENTALS OF ENHANCED IN SITU BIOREMEDIATION (EISB) Advantages of Enhanced Bioremediation for Chlorinated Solvents Cost Effective: As little as 1/3rd the cost of other options Destroys Contaminants: doesn t just move them High Concentrations Treatable: Including DNAPL sites Resistant to Rebound: Once down concentrations tend to stay down Sustainable: low carbon foot print/natural process/unobtrusive 2
EISB Tools Biostimulation: addition of electron donor, nutrients, buffering agents Bioaugmentation: addition of beneficial microorganisms KB-1 : Canadian bioaugmentation culture for chlorinated ethenes Lab Testing: Treatability studies and quantifying microbes to predict, optimize and assess remediation success Bioaugmentation Injection at BC site in 2014 each liter of KB 1 contains over 100 billion Dehalococcoides cells Advanced Application: - Hydraulic fracturing - Electrokinetics - Anaerobic injection water Dehalococcoides (Dhc) as Featured in Wired Magazine 3
Biodegradation of Chlorinated Ethenes By Reductive Dechlorination Can accumulate if DHC are absent lack VC reductase vcra Dehalobacter Dehalospirillum Desulfitobacterium Desulfuromonas +Dehalococcoides Only Dehalococcoides Ethene (aka. ethylene) is non-toxic, produced by many fruit to stimulate ripening TESTING AND BIOAUGMENTATION TO OPTIMIZE AND ASSESS REMEDIATION PERFORMANCE 4
Quantification of Dhc and Functional genes Testing for Dehalococcoides (Dhc) and vinyl chloride reductase (vcra) in groundwater to: Predict effectiveness of bioremediation in advance of field application (to stall or not to stall) SiREM Technicians preparing samples for Gene-Trac testing Confirm effectiveness of enhanced bio by quantifying growth and spread of Dhc Dhc quantification and spread after bioaugmentation at WY Site Treatability Testing Microcosms or columns constructed using site materials (soil, sediment or rock, and groundwater) Monitor contaminant reduction under different scenarios Customize treatment variables to meet site specific needs 5
Some Site Challenges Addressed Through Treatability Testing Electron donor/nutrient choices etc. Effectiveness of bioaugmentation Low ph and ph modification Dealing with contaminant concentrations & mixtures Technology synergies e.g. ISCO-Bio etc. Goal: determining contaminant degradation rate under different scenarios KB-1 101 Anaerobic culture: o Enriched from TCE site SW Ontario o Developed at U of Toronto Used to introduce Dhc to sites ~100 billion/liter Not genetically engineered/pathogen free Dehalococcoides KB-1/VC KB-1 is produced at SiREM s facility in Guelph, ON (above) shipped by air freight to site of application Added at 1/35,000 dilution in groundwater-need very little 6
Bioaugmentation Culture Field Application Culture vessel Argon Argon blanket Injection well MW-1 DHC-ve Dhc +ve MW-2 DHC-ve Dhc +ve Microbial Growth Ethene TCE DNAPL TCE Plume EISB FOR CHLORINATED SOLVENTS IN THE BC CONTEXT 7
Bioaugmentation Locations KB-1 Cultures have been applied at over 450 sites world wide with 2 Sites in BC to date plus additional sites in Pacific Northwest including AK, OR, WA Regulatory Landscape for Bioaugmentation Federal, Environment Canada: CEPA Bioaugmentation cultures require approval under New Substances Notification prior to use in Canada KB-1 cleared for groundwater remediation use in Canada in 2008 still only approved culture of its type BC MOE: Environmental Management Act Enhanced Attenuation protocols includes provisions for bioaugmentation First Application of KB-1 in Canada Thunder Bay ON 2009- First KB-1 Bioaugmentation in BC was in 2011 Adding species of microorganisms that are not naturally present in the hydrogeological system, but are necessary to facilitate biodegradation. BC MOE: 22 Technical Guidance on Contaminated Sites Version 1 Draft 15 Nov. 2014 8
Lower Mainland & vicinity has varied & complex geology/hydrogeology Impact of Geology/ Coastal Environment Alluvial sands silts, clays Glacial till Peat bogs Potential for low permeability Salt water intrusion Sedimentary fractured rock Bioaugmentation has been successfully applied in all of the above scenarios Site Conditions Appropriate for Bioremediation of Chlorinated Ethenes Anaerobic/Reducing DO < 0.2 mg/l ORP <-75 mv -often created by biostimulation where not pre-existing ph 6.0-8.5- for complete reductive dechlorination -e.g., ocean sediments often alkaline 7.8-8.5, peat bogs can be acidic ph neutralization is option Sulfate <1,000 mg/l, chloride typical of sea water OK (salt water intrusion sites typically below these concentrations) Warmer groundwater = faster results-groundwater temperature in southern/coastal BC generally well above 10 C sufficiently high for rapid biodegradation The right microbiology (i.e., Dehalococcoides) 9
Overcoming Geological/Geochemical Challenges Cold Groundwater: AK,ON,WI, DK Fractured Rock: GW recirculation systems ON,PA,NJ Low Permeability: DPT grids, hydraulic fracturing, WY and electrokinetics (EK) DK,FL Coastal Aquifers: KB-1 applied in numerous sea water impacted coastal sites, CA, FL, MA Low ph: sodium bicarbonate FL,BC EK-Study SiREM Alaska Seal Beach CA EK- Bio Denmark GW recirculation Ontario Fracturing Wyoming Bicarbonate buffering Florida Used to rapidly prepare anaerobic water to disperse and protect bioaugmentation cultures during application Produces injection ready water from tap water in hours with ORP <-100mV/ ph neutral Anaerobic Water Preparation KB-1 Primer Can be used to protect bioaugmentation for aerobic aquifers in single deployment applications donut approach KB-1 Primer slurry being applied to tote of injection water 10
Enhanced Bioremediation at BC Site (2011) PCE site with up to 25,000 µg/l Classified as high risk by BC MOE high concentration PCE E - Donors: ethanol, cheese whey, emulsified soy bean oil Injection of KB-1 using measurement device to apply small volumes of KB-1 to 39 injection locations at the Site Bioaugmented 39 locations (13 points 3 lifts) 2011 with 21 liters KB-1 Some locations with ph challenges (i.e.,< 6.0) ph neutralization required Dhc Quantification in Groundwater BC (2011) Site Bioaugmentation July 2011 Dehalococcoides/L 1.0E+09 1.0E+08 1.0E+07 1.0E+06 1.0E+05 1.0E+04 1.0E+03 1.0E+02 Optimal Dhc >1x10 7 /L MW A MW B MW C 1.0E+01 1.0E+00 Pre-bioaugmentation all wells ND for Dehalococcoides Post-bioaugmentation within 8-15 months all wells exceeded 10 8 Dhc/L 11
cvoc Results in MW BC Site 1 Bioaugmentation Concentration µg/l (as PCE) 2,000 1,000 PCE cdce VC Ethene TCE 0 Greater than 90% reduction in PCE and TCE within 2 years of EISB with complete dechlorination to ethene site was reclassified from high risk to low risk by BC MOE Conclusions Conclusions Bioremediation: cost, performance and sustainability benefits A variety of tools are available to assist with optimization of enhanced bioremediation remedies including: o Treatability studies o Dehalococcoides testing o Bioaugmentation o Anaerobic injection water o Advanced injection methodologies Successful BC applications of bioaugmentation leading to delisting as high risk sites by MOE within ~2 years of EISB 12
Questions Further Information siremlab.com 1-866-251-1747/519-515-0836 Phil Dennis: pdennis@siremlab.com 13