Background/Objectives: In addition to routinely being found in food packaging, non-stick pots and pans, water and stain repellent clothing, and various other products that resist heat, oil and stains, per- and polyfluroroalkyl substances (PFAS) have been used in the manufacturing of firefighting foams. Due to their water solubility and persistent nature, PFAS end up in groundwater and require treatment. The historical use of firefighting foam at the Royal Australian Air Force (RAAF) Base Tindal has resulted in groundwater contamination, which has been identified off the base, impacting a bore used in the Katherine water utility supply.

Approach/Activities: The Australian Department of Defence (Defence) had contracted an ion exchange resin technology at two of its properties on the East Coast of Australia. Following the identification of the contamination in Katherine, Defence revised its treatment objectives for one of the contracted systems and requested that the provider accelerate fabrication to deploy the system to Katherine as a priority. A 12.5 L/sec turnkey, modular system was provided that could consistently produce treated water with PFAS concentrations below the limit of reporting (LOR). Defence accelerated the delivery schedule by air-freighting the system from Maine in the U.S. to Darwin, Australia in an Antonov An-225 transport plane.

The PFAS water treatment system, which supplements the existing potable water treatment plant, included pre-treatment filtration and ion exchange to remove solids and other fouling agents, and specialized ion exchange resins for PFAS removal. The system was installed in international shipping containers, which allowed for easier transportation and rapid, “plug and play” on-site readiness. By manufacturing the system in a central fabrication shop, design engineers worked directly with structural, mechanical, electrical and instrumentation trades to ensure quality, efficient construction. This also facilitated operational debugging prior to shipment and translated to faster on-site readiness. The field crew worked cooperatively with Defence and the Northern Territory Power and Water Corporation (water utility provider) to efficiently install and start up the PFAS-removal system following delivery.

Results/Lessons Learned: Despite the revised treatment objectives, the entire design, fabrication, shipping and installation process took less than four months. The system went online in late October 2017, with influent total PFAS concentrations averaging 310 ng/l. It has been meeting all project objectives, including consistently achieving less than LOR effluent concentrations for all 34 PFAS compounds being monitored. This includes ultra-trace monitoring, measuring PFAS levels as low as 0.1 ng/l (ppt).

No resin change-outs have been required, and no PFAS breakthrough has been detected from the treatment system. The primary lesson learned has been properly managing the potential precipitation of calcium carbonate and associated resin fouling, as the groundwater is pumped from a karst formation, containing elevated levels of calcium and bicarbonate alkalinity. This challenge has been successfully controlled through the addition of 1 to 2 ppm of sequestering agent at the head of the treatment system.

Andy Bishop, Co-Founder, Emerging Compounds Treatment Technologies
Andy Bishop is the co-founder of ECT (Emerging Compounds Treatment Technologies). ECT is an equipment company focused on developing and commercializing treatment technologies for emerging, difficult-to-treat compounds. Andy’s responsibilities include directing engineering and project management efforts for the company’s product line.

Andy has 19 years of experience in water and wastewater treatment. His focus is currently on delivering innovative technology and design-build solutions for the treatment of 1,4-dioxane, perfluorinated compounds, and other emerging compounds.

Background/Objectives: Per and polyfluoroalkyl substances (PFAS) are increasingly being identified in groundwater and potable water supplies at concentrations exceeding Provincial and Federal guidance values and standards. PFAS are recalcitrant, mobile in the environment, and difficult to treat in situ. Currently, only stabilization techniques, such as sequestering or binding which do not provide degradation of PFAS, are being promoted for in situ remediation. To replace or supplement pump-and-treat technologies, in situ destructive technologies for PFAS need to be demonstrated at scale.

Previous work has shown significant rates of degradation of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) (>85%) via hydrogen peroxide catalyzed ozonation under alkaline conditions (Lin, et. al, 2012). For this work, methods similar to those employed in the Lin study were employed using a commercially available system.

Approach/Activities: Groundwater samples were collected from the most impacted portion of the PFAS groundwater plume at the subject sites. A screening matrix was developed to evaluate performance variables. Based on this screening matrix, bench-scale testing was conducted to assess application methodology, pH, and oxidant dosage on the destruction efficiency of PFAS using site groundwater impacted by a co-mingled plume containing high concentrations of both PFAS and other organics (chlorinated volatile organic compounds [VOCs] and petroleum-related constituents).

The results of the screening matrix were used to select optimum conditions to establish destruction dose-response curves for targeted contaminants and identify the optimal conditions needed to translate the bench-scale results into a field-scale pilot study. The testing considered 14 PFAS constituents included in USEPA Method 537 Revision 1.1, chlorinated VOCs, and petroleum-related constituents.

Results/Lessons Learned: This study is the first of its kind to translate previous academic testing into a potentially field-worthy application using commercially available advanced oxidation equipment. Impacts of process variables will be analyzed and discussed. The field pilot implementation plan will also be presented.

Scott Grieco, Principal Engineer and the North American Practice Leader for Emerging Contaminants, Jacobs
Dr. Scott Grieco is a Principal Engineer and the North American Practice Leader for Emerging Contaminants with Jacobs. His area of expertise is treatment of emerging contaminants and persistent environmental compounds. He has 26 years of experience in treatability testing, system evaluations, and process design. Scott has practiced in the field of emerging contaminants (ECs) for last eight years. He has completed bench, pilot, and full-scale of ECs, including groundwater, soil, municipal drinking water, and landfill leachate for PFAS. He is also a Visiting Professor at the State University of New York College of Environmental Science & Forestry. He has a BS in Chemical Engineering, MS in Environmental Engineering, and PhD in Bioprocess Engineering and is a registered Professional Engineer in New York.

Investigation and remediation of sites with emerging contaminant impacts, such as per- and polyfluoroalkyl substances (PFAS) and 1,4-dioxane, present unique project and risk management challenges. This presentation will provide an overview of the project and risk management challenges of two case studies. It will also provide best practices and lessons learned through the lens of the two case studies for risk identification and management on highly visible projects dealing with emerging contaminants.

The first case study involves water treatment for PFAS removal at an active manufacturing facility, where historical issues are concurrently under investigation and impacts to public water supply are being addressed as part of a separate, but related, project. This project involves coordination and communication across various departments and disciplines within the manufacturing company organization. Project stakeholders within the company include engineers, scientists, and operators housed in both the environmental and facility operations divisions. Water treatment targets associated with the project continue to evolve based on local and state regulatory influences.

The second case study involves the remediation of 1,4-dioxane at a public water supply serving over 20,000 people. Water supply impacts are the result of off-site groundwater contamination at a former ammunition manufacturing facility, and public communication and education needs were successfully addressed as a plan was developed to treat 1,4-dioxane.

Lisa Andrews, Senior Environmental Engineer, Barr Engineering Company
Lisa Andrews has more than 17 years of experience on municipal and industrial engineering projects and a strong background in chemistry and microbiology. Her areas of expertise include planning and conceptual design, process design for both water and wastewater treatment, pilot testing, construction support, multidisciplinary team coordination, regulatory compliance assistance, and project quality control.

Lisa has managed wastewater treatment projects for petroleum refineries, power plants, ferrous and non-ferrous mining projects, and agricultural clients. These projects have included water treatment evaluations, toxicity reduction evaluations, field studies, and pilot testing programs as well as the design of water treatment, wastewater treatment, and wastewater-reuse systems.