Toronto

Registration

Understanding the current Canadian screening values and regulatory landscape, the suitability and definition of available reference methodology and a review of difficult matrices and their impact to sensitivity

Alain Lesimple, Ph.D., PFAS Practice Leader at Eurofins

Methods (and techniques) for the analysis of PFAS have multiplied considerably and can be confusing, from those designed for drinking water to the newly issued Draft EPA Method 1633. In addition to those standard extraction techniques, we can also include the TOP Assay, TOF (total organic fluorine) and Non-Target Analysis (NTA). It would seem that there are quite a few tools at our disposal for assessing the impacts and presence of PFAS in the environment, as well as the effectiveness of remediation efforts. But what do all of these applications do for the practitioner investigating PFAS? Are they complimentary or are they distinct and separate in usefulness and the quality of data that is generated?

In this presentation, the current regulatory landscape in Canada will be discussed and clarified, we will give a brief over-view of the individual methodologies and the data that they provide, and how they relate to one another.

This presentation will look at the current state of analytical methods for the analysis of PFAS and will provide the following:

• Methods Comparison – A look at published drinking water methods
• Methods for non-potable water, solid matrices - what is available today and what is being worked on (Draft 1633)
• Key analytical techniques
• Matrix specific considerations
• A review of Canada provincial and federal specific guidelines
• Clarification of PFAS current regulation in Canada
• An introduction/review of new techniques for PFAS determination to compliment targeted compound approaches

Advances in Enhanced Anaerobic Bioremediation of Recalcitrant Chemicals

Jeff Roberts, M.Sc. Operations Manager at SiREM

Bioaugmentation with dechlorinating cultures such as KB-1^® and KB-1 Plus, is an established remediation technology for the enhanced anaerobic bioremediation of chlorinated solvents.  While Dehalococcoides (Dhc) are well known solvent dechlorinators, other dechlorinators including  Dehalobacter, Geobacter and Dehalogenimonas, provide further dechlorination capabilities. Gene-Trac^® testing for this wider range of dechlorinators, both before and after bioaugmentation,  provides a more complete picture of site remediation processes.     

SiREM has contributed to significant advances in characterizing of anaerobic benzene, toluene and xylene (BTX) biodegraders, development of bioaugmentation cultures (DGG-Plus™) and developing Gene-Trac^® tests to monitor these processes in situ. These tools provide bioremediation solutions at gasoline and other BTX contaminated sites where traditional aerobic remediation approaches are not. 

Bioremediation for chlorinated solvents and BTX compounds is one of the lowest cost options and bioaugmentation has the potential to decrease remediation time frames and increase the range of sites to which bioremediation is applicable. This presentation will discuss recent advancements in bioaugmentation cultures, molecular biological tools and provide case studies where bioremediation was the remedy of choice at chlorinated solvent and petroleum hydrocarbon sites.

Lunch

Keynote: Adventures in Anaerobic Bioremediation

Elizabeth Edwards, Ph.D.,P.Eng., University of Toronto

Break

Heat Enhanced In-Situ Alcoholysis for Reductive Bioremediation

David F. Alden P.E., MSc., Manager of Technical Services at Tersus Environmental

Anaerobic in-situ remediation has emerged in recent years as a viable and cost-effective remediation strategy for recalcitrant contaminants. The process is used to modify chemical, physical, and biological conditions in soil and groundwater to facilitate degradation of a broad range of contaminants under anaerobic conditions to harmless end products. Emulsified vegetable oil (EVO) is often used as an assimilable carbon source as it slowly ferments and can act in the subsurface as an organic carbon and hydrogen source that stimulates organohalide-respiring bacteria that in turn mineralize chlorinated solvents. 

Although emulsifying vegetable oil allowed overcoming limitations of pure vegetable oil injection and minimize field interventions by using a long-lasting electron donor, hundreds of EVO injection events over the past years has demonstrated that EVO effects are limited to the area in the immediate vicinity of the injection point. This is evident through low TOC values measured even tens of meters downgradient to injection points, and the TOC is composed predominantly of acetic acid, as opposed to a more diverse fatty acid composition. Another inconvenience of EVO injections is biofouling of the matrix and particularly screened injection wells. This phenomenon is typically attributed to biomass developing in the aerobic vicinity of injection wells due to hydrophobic oils creating a film (residual electron donor) that stimulates biomass growth. In many cases, biofouling or permeability losses could very well be attributed to geochemical incompatibilities between EVO and cations in the subsurface, or EVO’s intrinsically high retention to soils.

Enhanced reductive bioremediation using In-Situ Alcoholysis overcomes two of the main challenges associated with EVO injection: poor fatty acid subsurface distribution and biofouling. The method is generally directed towards transesterification of vegetable oils to improve formation and distribution of slowly fermenting and soluble electron donors that are favorable to anaerobic reductive bioremediation. 

Recent field work in the US and Australia has demonstrated that In-Situ Alcoholysis reactions can within 90 days reduce over 90% of the contaminant mass. Because the typical aquifer temperature is about 15°C, adding heat further enhances this process as the reaction temperature significantly influences the transesterification reaction.  Based on temperature, the time needed for the transesterification reactions drops to hours from the expected months. Heat also enhances the degradation rates. Löffler et al. 2013 identified an optimal range of 25-30°C for neutrophilic, strictly hydrogenotrophic Dhc strains.

Heat sources include steam, electrical resistance heating, thermal conduction heating, gas thermal heating or residual heat from an in-situ thermal remediation project. Lower cost options are under development. This presentation will discuss methods of heating the amendment mixture and injecting hot water. Using hot water offers many advantages. In general, hot water dissolves fewer gases (like oxygen or carbon dioxide) but more solids (sugars) than cold water.   Temperature modeling temperature at the injection of water heated to 90°C into 3 injection wells at a flow rate of 150 m³/d was able to maintain temperatures of greater than 30°C for 10 days in the vicinity of the injection wells.  Remediation results presented will show the benefits of this approach.

Horizontal Directional Drilling and Well Installation for Substrate Injection

David S. Bardsley, PG, Geologist - Business Development at Ellingson-DTD

Panel Closing Remarks

Drawing (Must be Present to Win)