In-Situ Chemical Oxidation (ISCO) Delivery Optimization

Presented by: Bruce Tunnicliffe, Vertex Environmental Inc.

Use of In-Situ Chemical Oxidation (ISCO) for subsurface remediation of soil and groundwater has increased dramatically over the past 10 years. ISCO techniques are becoming increasingly recognized and recommended by environmental firms. The reaction chemistry is relatively well understood for common contaminants of concern. However, application of ISCO can be problematic, as there can be improper delivery of the remedial amendment into subsurface resulting in incomplete contact with the contamination.
The purpose of this talk is to explore various methods to ensure better contact between the remedial amendment and the subsurface contamination. Two amendment delivery methods will be compared and contrasted, specifically injection into wells and injection using temporary points. Examples of when these delivery methods should be used will be presented. The results of a laboratory experiment will be presented visually showcasing how delivery of a solution occurs in the subsurface in a sand aquifer with clay aquitards.

Soluble Carbon-Iron Product for In-situ Remediation of Groundwater

Presented by: Jean Paré, Chemco Inc./FMC

In Situ and Ex Situ Chemical Reduction has been effectively used on hundreds of sites worldwide for remediation of chloroethenes, chloroethanes, carbon tetrachloride and daughter compounds, and pesticides in groundwater. Often product used consists of a combination of solid, plant-based carbon powder and fine zero valent iron (ZVI).

The product is slurried and injected into the impacted groundwater plume to create ideal conditions for reductive dechlorination. As the carbon ferments, soluble volatile fatty acids (VFAs) are released to the groundwater to provide the preferred carbon source (i.e., VFAs) for indigenous dehalogenating microorganisms. The ZVI provides a reactive surface for abiotic dechlorination and releases soluble iron (Fe2+) which later precipitates to form additional reactive mineral surfaces downgradient from the injection zone. In combination, the VFAs and ZVI create very strong, stable reducing conditions which make dechlorination reactions more energetically feasible.

Thisblend of product is highly effective, but as a solid there can be limitations to its applicability at some sites with very tight formations or existing permanent well systems. A liquid version was developed to address these limitations. Like the solid forumation, the new liquid product is based on a combination of slow-release fermentable carbon and iron and is 100% cold-water soluble. Following extensive research and development work in our laboratory, we identified an optimum combination of lecithin, which is very slowly metabolized, and a specialized ferrous salt that is protected from rapid oxidation. Lecithin vesicles that form upon emulsification provide further protection to the ferrous iron to ensure oxidation does not occur until after the product is injected, and then at a controlled rate.

Studies conducted in our laboratory indicate the liquid product supports TCE treatment efficiencies similar to those attained with the soldi version. Beginning in the spring of 2011, field pilot tests were initiated to obtain field data on removal efficiencies supported by the liquid version. Results from these projects and a discussion of difficulties encountered will be discussed.

In-Situ Treatment of Home Heating Oil Spills

Presented by: Leaonard Chan, CCC

Sites impacted by home heating oil spills can pose challenges due to restricted access, elevated contaminant concentrations, and limited remedial efficiency due to sorption. Traditionally, excavation has been used, but alternative techniques and approaches such as chemical oxidation, surfactants, and bioremediation can be used either as standalone or complementary methodologies to cost-effectively achieve project goals. We will provide a basic overview of remedial design considerations and then present case studies that highlight various clean-up options.

Buying Best Value - Procuring Remediation Work

Presented by: Craig Wells, Department of National Defence (DND)

The Goose Bay Remediation Project is a long-term multi-million dollar contaminated site remediation project managed by the Department of National Defence, and funded by the Federal Contaminated Sites Action Plan program.  The goal of the project is to remediate or risk-manage contamination at 5 Wing Goose Bay resulting from decades of site operation in a way that does not pose a long-term risk to human health or the environment.  Due to the nature, extent, and variety of contamination – such as hydrocarbons, heavy metals, pesticides, PCBs, and PAHs – we will be using a wide variety of different remedial techniques, all of which have specific requirements and unique challenges.

Other than project and contract management, and technical oversight, 100% of the activities required to deliver the project require procured services.  To meet the schedule and budget constraints of the project, procurement planning for project activities is an essential requirement, and much effort has been dedicated to improving how we tender and manage contracts within a relatively small project team.

Planning procurements that are fair, transparent, and good value to the Government of Canada while also being viable, interesting, and attractive to industry is a significant challenge for the project team.  It is also not easy to encourage innovation and flexibility in a framework that must follow a common set of standards in order to be fairly evaluated.  Specifically, performance-based contracting is a unique challenge in the public sector.  It requires a good understanding of the risks that exist for both parties, and finding ways to balance those risks to a tolerable level.

This presentation will identify some of the constraints that are unique to procurement in the public sector, and how we use lessons learned, communications with industry, flexibility in our planning, and a balanced approach to risk to generate contracts that meet the project goals while being viable for private industry.

Brownfield Development and Remediation Technology Selection - An Industry Perspective

Presented by: Scott Lewis, Cobalt Properties

This presentation will discuss how Cobalt’s Environmental Management Program incorporates the assessment and management of environmental risk while providing fiscally responsibility from a developer’s perspective.  It will also cover Cobalt’s redevelopment of properties owned and under management to a ‘higher and better use’ and the importance of exploring, validating and deploying new technologies and leveraging scientific techniques to further the redevelopment of brownfield sites for all stakeholders.

Chemical Reduction for In Situ Soluble Metals Remediation

Presented By: Jean Paré, Chemco Inc./FMC

As our society is aiming for a more sustainable lifestyle in respect of a balance between environmental, social and economic factors, the use of efficient and environmentally friendly remediation technologies is now required by the environmental industry including landlords, governments, engineering firms,contractors and suppliers. This is changing the ways we are approaching and developing intervention strategies for contaminated site remediation and rehabilitation.

In Situ and Ex Situ technologies are commonly used for the remediation of organic and inorganic contaminants in soil and groundwater. These technologies are well established and recognized by the specialized environmental firms and the different levels of governments.

This presentation allows to review and better understand the theory, principles and applicability of Chemical Reduction for the remediation of a wide range of contaminants such as chlorinated solvents (ethanes, ethenes, methanes, perchlorate, etc.); organochlorine pesticides and herbicides; energetic compounds (TNT, RDX, etc.); phenolic compounds (PCP, PAHs) and some petroleum hydrocarbons; and dissolved metals. The presentation will also cover the various ways to establish reductive conditions in the soil and/or groundwater through the use of both organic and inorganic amendments. Laboratory data and field case studies will be presented to better understand where and how these remediation technologies canbe successfully applied.

Innovative Plume Stability Analysis And Remediation System Benefit Analysis (RSBA)

Presented By: Joe A.Ricker, EarthCon Consultants, Inc.

Evaluating the relative stability of a groundwater contaminant plume is generating increasing attention as many state regulatory agencies, EPA and private stakeholders are realizing the applicability of plume stability as part of the environmental evaluation and/or remedial planning process of a site. Specifically, a plume stability evaluation will allow the stakeholder to assess whether a contaminant plume is stable, decreasing or increasing in size. Assessing the stability of a plume will allow the stakeholder to evaluate whether additional remedial action is necessary or whether risk-based closure of a site may be applicable or whether MNA is occurring at a site. There are many other ancillary applications of plume stability evaluations as related to groundwater contamination.

This session presents the Ricker Method for plume stability analysis, which entails the use of innovative techniques to calculate and assess historical trends in contaminant plume area, average concentration, contaminant mass, and center of mass. This session will also present certain aspects of a proprietary analysis tool called Remediation System Benefit Analysis (RSBA). RSBA is an interpretation of the relative benefit of a remediation system based on graphical data outputs created from the Ricker Method of evaluating plume stability and additional data inputs. In effect, what RSBA does is evaluate the efficiency of an active groundwater remediation system that removes contaminant mass from groundwater (e.g., pump and treat). The tool evaluates whether an active system may be considered efficient or inefficient based on an evaluation of contaminant mass removed via the system and the relative stability of a groundwater plume.

The Ricker Method for plume stability analysis was published in Groundwater Monitoring & Remediation (28, no. 4/ Fall 2008/pages 85–94) and has been used at numerous contaminated sites to effectively demonstrate the stability of contaminant plumes comprised of chlorinated solvents, carbon tetrachloride, pentachlorophenol (PCP), creosote, naphthalene, benzene, nickel and sodium, among others.

Remediation using In Situ Chemical Oxidation and Accelerated Anaerobic Biodegradation

Presented By: Todd Herrington, Regenesis

The individual use of in situ remediation technologies such as microbially mediated enhanced anaerobic biodegradation (reductive dechlorination) and chemical destruction based in situ chemical oxidation (ISCO) for the treatment of chlorinated compounds has been widely documented and accepted with varying degrees of success. Due to the known limitations of each of these approaches (Bio vs. ISCO), the practice of combining or integrating these two technologies is emerging as an effective strategy for optimizing chlorinated contaminant treatment. More specifically the use of a catalytic ISCO reagent applied in sequence with a staged‐release, electron donor microemulsion for enhanced anaerobic bioremediation has been shown to be successful at chlorinated sites. Perchloroethene (PCE), trichloroethene (TCE) and dichlorethene (DCE) in high concentrations (mg/L levels and above) can be destroyed effectively with ISCO. However, in most cases, ISCO is only effective at reducing mass, and in the case of a catalytic percarbonate based reagent create highly aerobic conditions for some time following injection. Post‐ISCO application, chlorinated solvents can linger on at low levels (< 1 mg/L) in the dissolved‐phase. To target residual dissolved‐phase concentrations, the use of enhanced anaerobic dechlorination is a compatible and efficient follow‐on application to ISCO to reach treatment goals. Timing is key in going from aerobic conditions created by ISCO to an anaerobic biodegradation process. In this case the use of a percarbonate‐based catalytic ISCO agent requires some re‐acclimation time for the aquifer to buffer the ISCO‐induced high DO, ORP, etc. Subsequently the application of a staged‐release, microemulsion electron donor can be completed. This abstract will discuss the details of this process as well as performance based case study documentation of its success.

Using High Resolution Characterization for Detailed Real-Time Assessment of LNAPL and Dissolved Phase Petroleum Hydrocarbons

Presented By: Bruce Tunnicliffe, Vertex Environmental Inc.

A common problem with remediation of petroleum hydrocarbons (PHCs) is a lack of understanding of subsurface distribution. Basic information is obtained using traditional boreholes and monitoring wells, but significant data gaps typically remain prior to commencement of remediation. Two new high resolution characterization techniques have been successfully used to define the location of PHCs in-situ, these are the Membrane Interface Probe (MIP) for dissolved phase contamination, and Laser-induced fluorescence (LIF) for free phase contamination (LNAPL – light non aqueous phase liquid).

The MIP and LIF are powerful down-hole assessment tools that are used to provide semi-quantitative data on subsurface contamination. Advanced to depth by direct push methods, the surface of the MIP probe is then heated and the volatile contaminants volatilize and diffuse through a semi-permeable membrane and are subsequently transported to the surface for analysis. The LIF consists of a probe with a fibre optic cable that emits light through a window in the probe during direct push advancement. The PHCs in LNAPL fluoresce and the response is measured by the probe in real time. These real time, high resolution technologies provides very detailed information about the presence and extent of PHC impacts.

During this talk, each technology will be briefly discussed, and a case study will be presented where both the MIP and the LIF were used prior to and during in-situ remediation of PHCs. This talk will present the pre-injection MIP and LIF results and showcase how the initial chemical oxidation design was altered based upon the MIP and LIF results. The MIP and LIF were remobilized to the Site during the in-situ program, these results will also be presented to show how the results were used to alter the design which resulted in efficient distribution of the oxidant and good destruction of the PHCs.

Phytoremediation of Salt and Petroleum Hydrocarbon Impacted Soil

Presented By: Perry D. Gerwing, Earthmaster Environmental Strategies Inc.

Based on extensive chemical and biological research, we have successfully developed and implemented plant growth promoting rhizobacteria (PGPR) enhanced phytoremediation systems (PEPS). The scientifically advanced phytoremediation systems we deploy remove petroleum hydrocarbons (PHCs) and salt from soils. PEPS provide large amounts of root biomass in impacted soils, which promotes growth of rhizosphere microorganisms. The root and rhizosphere biomass allow rapid partitioning of contaminants out of the soil, and their subsequent uptake and/or metabolism by microbes and plants. This results in degradation of PHCs in soil and large amounts of biomass for sequestration of salt into plant foliage. We have deployed PEPS at over 35 full‐scale sites in Canada. PEPS, when deployed by our trained scientists, will result in PHC and salt remediation to Tier 1 standards. Not only is this a green solution for remediation of impacted sites, but the costs for PEPS are less than half the costs associated with landfill disposal. Between 2007 and 2012 we have deployed PEPS at more than 25 PHC impacted sites in Alberta, British Columbia, Ontario, Manitoba, the Northwest Territories and Quebec. At all sites we achieved ~ 35 % remediation per year of PHC from soil (mostly F2, F3 and F4). The first 7 sites treated have met Tier 1 standards while 18 other sites are being treated and are on target to reach remedial endpoints within an overall 2 to 3 year treatment period. Beginning in 2009, we initiated full scale deployments of PEPS at 13 salt impacted sites in Saskatchewan, Alberta, Manitoba and the Northwest Territories. PGPR greatly enhanced plant growth on the salt impacted soils, allowing excellent plant growth with soil ECe’s up to 25 dS/cm. Furthermore, the plants (both grasses and cereals) take up sufficient amounts of salt to result in 10 to 20 % remediation per year. Importantly, we have already achieved salt remediation to regulatory targets at 2 of the sites. We have an on‐going research program to improve PEPS. One aspect of this work is to properly maintain the PGPR currently utilized and to isolate new, more active PGPR. We are refining the CCME PHC analytical method to make phytoremediation and other green in situ remediation technologies more efficient. We are also using Tier 2 toxicity end points at a research level to assess when soil becomes non‐toxic during PEPS treatment – results indicate this will occur prior to meeting Tier 1 criteria. Our work with PEPS has shown that it is very effective for treatment of a wide variety of PHC and salt impacted sites (including sites with co‐contaminants).