Steve is the President and co-founder of ECT2 (Emerging Compounds Treatment Technologies). ECT2 is an equipment company focused on developing and commercializing treatment technologies for emerging, difficult-to-treat contaminants. Steve’s focus is currently on commercializing Synthetic Media technologies for the sustainable treatment of PFAS and 1,4-dioxane. He received his Ph.D. in Environmental Engineering from Purdue University in 1992.
Innovative Waste Minimisation During PFAS Contaminated Water Remediation
INTRODUCTION: As part of its response to per- and poly-fluoroalkyl substances (PFAS) contamination resulting from the historical uses of aqueous film forming foam (AFFF), the Australian Department of Defence (Defence) completed a detailed environmental site investigation of an area of over 150 square kilometres, incorporating RAAF Base Tindal and private land in the vicinity of the Defence property. The investigation identified that PFAS contamination had entered groundwater and migrated offsite towards the Katherine River. RAAF Base Tindal is located in the Northern Territory, approximately 17 kilometres from Katherine and 330 kilometres from Darwin. The location of the property makes it critical that any equipment and consumables needed, or waste removed from the property, are carefully considered as it is logistically challenging to transport products to and from the property, particularly during the wet season. In addition, waste disposal and treatment facilities are limited in the NT.
APPROACH: ECT2 has installed a water treatment system at each of the two main groundwater source areas on the Tindal property; the Fire Training Area (FTA) and the Fire Station Area (FSA). The central regeneration system is located alongside the FTA water treatment system and serves both the FTA and the FSA. Contaminated groundwater is extracted from wells located within each of the plumes and is pumped to the two individual treatment systems. PFAS concentrations of up to 50ug/l are being treated at the Fire Station Area and up to 40ug/l at the FTA. Regenerable ion exchange (IX) resin is being used to remove PFAS compounds from the water using a lead/lag/polish treatment train arrangement.
RESULTS AND DISCUSSION: The FTA treatment system was commissioned in December 2018 and the FTS system was commissioned in March 2019. The use of multiple extraction wells has allowed contaminated water to be extracted from various combinations of wells, providing operators with the ability to maximise PFAS mass removal from the well network, thereby optimising the remediation efforts. Treated effluent quality has been consistent at both the FTA and FSA, consistently below the level of reporting (LOR) for all 28 PFAS compounds being monitored. The use of IX resin proven to have a high capacity for the removal of PFAS, combined with the unique resin regeneration technology, has resulted in the generation of minimal PFAS waste, while treating approximately 580,000 gallons of water per day. The lead/lag configuration of the resin vessels, multiple electronic failsafe features and remote monitoring capabilities has helped facilitate 98% uptime during 24/7 operations.
CONCLUSIONS: The application of innovative technology at RAAF Base Tindal has proven effective at consistently providing a very high level of PFAS removal, while minimizing PFAS waste generation to less than 1 gallon of waste per million gallons treated. This has helped avoid passing along the problem for future generations to resolve and has greatly diminished the reliance subsequent thermal desorption/destruction, which requires significant transportation and energy use.
Source Removal Combined with Drinking Water Treatment on a PFAS-Contaminated Groundwater
INTRODUCTION: The United States Air Force Civil Engineering Center (AFCEC) has conducted response activities to remove and remediate groundwater impacted by poly- and perfluoroalkyl substances (PFAS) at the former Pease Air Force Base in New Hampshire. A regenerable resin system was selected for full-scale application, based on pilot system performance and a lower overall lifecycle cost than GAC. Similar work was conducted in parallel on drinking water supply wells for the City of Portsmouth, New Hampshire which are also affected by contamination from the Pease Air Force Base. The City wanted to run long-term PFAS treatability testing on the heavily contaminated Haven Well but were not able to run the tests at full scale. A side-by-side pilot test was conducted to compare the effectiveness of ECT2’s single-use SORBIX LC1 IX resin versus Calgon’s F400 GAC.
APPROACH: A 200-galon per minute (gpm) system was provided at the FTA source area to meet the primary project objective of producing treated water to below the 70 ng/l HAL. The full-scale, regenerable IX resin system was installed from fall 2017 through spring 2018. For the drinking water system, the pilot system was designed and fabricated to pump directly from the Haven Well using a peristaltic pump. The skid was double sided, supporting resin columns on one side and GAC columns on the other. Each of the two sides had four columns in series, each with a 2.5-minute empty bed contact time (EBCT). This setup facilitated the comparison of four different EBCTs; 2.5, 5, 7.5 and 10 minutes. Samples were routinely taken from the raw influent and from each column effluent, and analyses were performed for 23 PFAS compounds. Breakthrough curves were then plotted to compare the effectiveness of GAC versus IX resin for PFAS removal.
RESULTS AND DISCUSSION: The full-scale FTA source area remediation system began operation in April 2018. The effluent quality from the IX resin system has been consistently non-detect for all 13 monitored PFAS compounds, including the short-chain species, readily achieving compliance with the 70 ng/l HAL target. Five successful resin regenerations had been performed by late April 2019. For the drinking water system, the influent total PFAS concentration averaged 3.5 ug/l over the course of the year-long pilot test. The IX resin substantially out-performed the GAC on all 12 PFAS that were present at detectable levels. Based on the results of the comparative pilot test and the associated lifecycle cost comparison, the City selected LC1 IX resin for full-scale implementation to remove PFAS from the Haven water supply.
CONCLUSIONS: Both the full-scale FTA source area remediation system and the drinking water pilot treatment system have effectively used IX resin to remove PFAS from groundwater. The source area system has utilized a regenerable IX resin system to maintain consistent compliance with the 0.07 ug/l HAL, while minimizing waste generation. The drinking water pilot system demonstrated the superior PFAS-removal performance of single-use IX resin compared to GAC. The full-scale resin drinking water treatment system is scheduled to go online in spring 2020.