2019 SMART Remediation Ottawa – February 7, 2019

Paul McCulloch, MECP
Communicating Effectively with the MECP
Bio | Abstract | Presentation

Marc McAree, Willms & Shier Environmental Lawyers LLP
Court Upholds MECP’s EPA No‐Fault Order Requiring Off‐Site Soil Vapour, Groundwater and Surface Water Investigation
Bio | Abstract | Presentation

Meggen Janes, Waterfront Toronto
Toronto Port Lands and Developing Remediation Goals
Bio | Abstract | Presentation

Carl Spensieri, Berkley Canada
Managing Consultant and Contractor Risk & Environmental Insurance
Bio | Abstract | Presentation

Bob Kennedy, newterra
Emerging Contaminants – a Primer
Bio | Abstract | Presentation

Paul Hurst, Golder Associates Ltd.
Case Study – Complete Vapour Intrusion Mitigation Services for an Industrial Plant
Bio | Abstract | Presentation

Case Study – Complete Vapour Intrusion Mitigation Services for an Industrial Plant

A plastics manufacturing plant with documented indoor air concentrations of trichloroethene (TCE) above the State’s response levels required a multi-pronged approach to mitigate both indoor air and sub-slab sources of TCE. This approach consisted of a data review to understand TCE sources and building conditions, investigation of vapour intrusion (VI) pathways and mitigation works to reduce indoor air concentrations of TCE to acceptable levels. During the investigation stage, Golder completed a novel assessment of contamination sources and transport pathways through a combination of multiple rounds of grid-based indoor air and sub-slab vapour testing of TCE and other chlorinated solvent chemicals, the use of an on-site portable laboratory that provided low level air concentration data at a high resolution and consequently was highly effective, video surveys of utilities, continuous differential pressure monitoring to assess gradients that could affect contaminant mobility, and flux chamber testing to assess potential indoor air TCE sources. This comprehensive approach was needed because of the complex building conditions and varied potential sources. Air conveyance testing was conducted to support design of a sub-slab depressurization (SSD) system. Interim mitigation included the provision of climate controlled fresh air in order to increase the effective air exchanges rates and reduce TCE concentrations. Understanding how indoor air TCE concentrations responded to increased air exchanges informed needed modifications to the building HVAC system as part of the overall VI mitigation program. Golder provided a complete set of services consisting of engineering design, preparation of specifications and tender, review of tender, construction monitoring and on-going performance monitoring and client support. Based on air conveyance testing, nine extraction sumps and two, 600 CFM blowers to allow for system redundancy were installed and commissioned. This case study presents the investigation results, VI mitigation conducted and current state of the project.

Sandra Dworatzek, SiREM
Advances in Anaerobic Bioremediation of Benzene
Bio | Abstract | Presentation

Advances in Anaerobic Bioremediation of Benzene

Widespread use of petroleum products has resulted in contamination with BTEX compounds at numerous sites. BTEX compounds, which are the most soluble of petroleum hydrocarbons, can readily biodegrade under aerobic conditions, however where anaerobic conditions prevail, natural attenuation of BTEX has also been observed. Most often, under anaerobic conditions, benzene is observed to persist, due to its recalcitrance to degradation and can become a regulatory driver for remediation. Several benzene degrading cultures have been identified including a methanogenic benzene enrichment culture (DGG-B), developed at the University of Toronto. DGG-B transforms benzene and produces methane and the key benzene degrader, Deltaproteobacteria ORM-2, has been identified. This culture also degrades benzene under sulfate reducing conditions. Recent research efforts have been undertaken to determine 1) whether bioaugmentation with the DGG-B culture is an effective remedy for benzene contaminated sites; 2) if the presence of benzene degrading biomarkers can be correlated to in situ biodegradation activity and 3) if scale up of the culture to volumes sufficient for field pilot testing application is feasible. Numerous anaerobic treatability studies have been conducted using site materials impacted with petroleum hydrocarbons. The time frame for these treatability studies ranged from 8 to 14 months. Degradation of BTEX was monitored with and without DGG-B bioaugmentation and under various electron acceptor conditions. The results to date indicate that bioaugmentation with the DGG-B culture was able to accelerate benzene degradation under methanogenic or sulfate-reducing conditions, while in one case, no benzene degradation was observed despite bioaugmentation. Results from ongoing treatability studies will be presented to provide insights into the performance of the DGG-B bioaugmentation culture at a range of petroleum hydrocarbon contaminated sites, as well as into the correlation between the presence of benzene degradation molecular biomarkers and in situ biodegradation.

Jean Paré, Chemco inc.
Evaluation of ISCR PRB Longevity under High Sulfate and High Flux
Bio | Abstract | Presentation

Evaluation of ISCR PRB Longevity under High Sulfate and High Flux

Background/Objective. Historical grain storage facility fumigation operations resulted in groundwater Carbon Tetrachloride (CT) impacts in a small Kansas farming community. High site groundwater flow velocity (estimated at ~700 ft year) has resulted in the CT plume extending approximately 2,500 feet downgradient where it discharges into a small creek; the highest concentrations of CT (approximately 1,500 ug/L) are located near the source area. To limit further plume migration, a Permeable Reactive Barrier (PRB) was installed across the plume width to passively treat CT. The PRB was constructed by injecting EHC® slurry in to a line of direct push injection points. EHC is composed of slow-release plant-derived organic carbon plus micro-scale ZVI particles. Inflowing groundwater is sulfate rich (~120 mg/L), potentially affecting substrate consumption rates and treatment zone reactive life. This presentation reviews geochemical parameter response and CT removal rates over time downgradient of the PRB and compares them with theoretical calculations on ZVI consumption rates using site specific data. These calculations are then discussed relative to the > 10 year PRB longevity and apparent mechanisms for the extended life. Approach/Activities. 48,000 lbs of EHC was injected into an area measuring approximately 270 ft long x 10 ft wide x 9 ft thick on average. The PRB was installed along a road and extended across the width of the plume to limit further plume migration. PRB effectiveness is measured at two compliance wells located 70 and 140 ft downgradient from the PRB. Monitoring is performed on a bi-yearly basis and includes CVOCs and geochemical parameters. Total Organic Carbon (TOC) is monitored as an EHC reagent indicator while ORP, Dissolved Oxygen (DO), nitrate and sulfate are monitored to assess redox conditions in the downgradient zone. Direct measurements of iron have not been performed, but iron consumption rates have been estimated based on inflowing concentrations of terminal electron acceptors. Results/Lessons Learned. CT removal rates peaked 16 months after installation at >99 percent removal. Two years after installation these rates decreased slightly to approximately 95 percent removal and have stabilized around that level for over ten years continuously supporting inflowing groundwater treatment. A significant increase in TOC was measured 70 ft downgradient from the PRB during the first two years. Since then, TOC levels have returned closer to background levels, suggesting that the more readily degradable carbon component (cellulose) had been consumed. During this initial phase redox conditions also reached their lowest point concurrently with significant reductions in inflowing nitrate and sulfate. After TOC levels returned closer to background, sulfate levels also moved closer to inflowing concentrations while ORP remained significantly below background. Theoretical ZVI consumption calculations suggest the ZVI may be consumed after 2.7 years if reacting Stoichiometrically with inflowing sulfate. However, geochemical data suggest that ZVI by itself is not supporting significant sulfate reduction. The probable explanation for the long PRB reactive life is the formation of an iron sulfide mineral based reactive zone created downgradient of the PRB during the initial sulfate reduction phase and since acting as an electron reservoir. This zone may also be continuously rejuvenated by low levels of TOC in inflowing groundwater (~2 mg/L) and from the hydrogen produced from ongoing ZVI corrosion.

David Alden, Tersus Environmental
5 Lessons Learned From Surfactant‐Enhanced Aquifer Remediation of Light and Dense NAPLs
Bio | Abstract | Presentation

Daniel Bouchard, Sanexen
What Additional Value Can Compound Specific Isotope Analysis (CSIA) Bring to the Assessment of Organic Contaminants in Groundwater?
Bio | Abstract | Presentation

What Additional Value Can Compound Specific Isotope Analysis (CSIA) Bring to the Assessment of Organic Contaminants in Groundwater?

Over the last three decades, compound-specific isotope analysis (CSIA) has evolved from the state of laboratory studies to a recognized, highly-sensitive field assessment tool. For this reason, the tool has been deployed on numerous contaminated sites to gain key information on released organic compounds (such as petroleum hydrocarbons and chlorinated solvents) that traditional concentration measurements are unable to reveal. For instance, CSIA has proven its reliability and robustness in demonstrating the biological destruction of organic compounds in groundwater, thus becoming an indicated tool for use in the framework of a Monitored Natural Attenuation program. CSIA greatly enhances the quality of information derived from the dataset collected over time, strengthens the conclusions drawn on the fate of organic contaminants in groundwater, and reinforces the Regulator’s decision to approve on-site application of the natural attenuation remedial strategy. Furthermore, the tool has been used to differentiate sources of the same contaminant present in the subsurface for forensic purposes, or to better understand source architecture on complex sites having the potential for multiple release episodes. More recently, the application of the tool has reached another milestone, when it was applied in the framework of in situ remediation treatments to assess whether the intended contaminant mass reduction was initiated as anticipated. More specifically, CSIA was proven reliable in determining whether the contaminant mass reduction observed was attributed to dilution or destruction, or which co-occurring physical, chemical or biological process was the dominant mass-reduction process. In such cases, application of CSIA supports field practitioner’s decision to modify the treatment in real time, which leads to cost-effective remediation treatments. This talk aims to briefly explain the fundamentals of the CSIA method, followed by examples of field applications.