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Development of a Cost Effective 1,4-Dioxane Treatment System for Small Community Water Supplies
Citation:
Namboodiri, V., D. Cutt, I. Katz, J. Battipaglia, D. Gwisdalla, F. Alvarez, AND M. Pensak. Development of a Cost Effective 1,4-Dioxane Treatment System for Small Community Water Supplies. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-23/075, 2023.
Impact/Purpose:
1,4-dioxane is a high priority chemical in EPA Region 2 due to its widespread occurrence throughout the region and the low regulatory limits established by the New Jersey Department of Environmental Protection (NJDEP). As of 2014, there were 544 detections of TCA (a common co-contaminant of 1,4-dioxane) in groundwater throughout New Jersey; however, these numbers likely underestimate the occurrence of 1,4-dioxane in groundwater across the state. The New York State Department of Environmental Conservation (NYSDEC) is also working with EPA Region 2 to sample for 1,4-dioxane in groundwater at 725 remedial program sites across the state of New York. The preliminary data indicate that exceedances above the proposed MCL of 1 µg/L occurred at 174, or 24%, of the sites. NYSDEC is currently evaluating a Maximum Contaminant Level (MCL) recommendation of 1 µg/L for 1,4-dioxane from the New York Drinking Water Quality Council. If adopted, it would be the nation’s most stringent drinking water standard for 1,4-dioxane. ORD's objective of this RARE project research with Region 2 and NJDEP was to develop and evaluate a cost-effective, low-maintenance 1,4-dioxane treatment technology for small-scale Point of Entry Treatment (POET) systems.
Description:
1,4-dioxane is a likely human carcinogen and has been found in groundwater and drinking water supplies throughout the United States. Historically, 90% of 1,4-dioxane production was used as a stabilizer in chlorinated solvents, such as 1,1,1-trichloroethane (TCA). The physical and chemical properties and behavior of 1,4-dioxane create challenges for its characterization and treatment. It is highly mobile and does not readily biodegrade in the environment. 1,4-dioxane is a high priority chemical in EPA Region 2 due to its widespread occurrence throughout the region and the low regulatory limits established by the New Jersey Department of Environmental Protection (NJDEP). As of 2014, there were 544 detections of TCA (a common co-contaminant of 1,4-dioxane) in groundwater throughout New Jersey; however, these numbers likely underestimate the occurrence of 1,4-dioxane in groundwater across the state. The New York State Department of Environmental Conservation (NYSDEC) is also working with EPA Region 2 to sample for 1,4-dioxane in groundwater at 725 remedial program sites across the state of New York. The preliminary data indicate that exceedances above the proposed MCL of 1 µg/L occurred at 174, or 24%, of the sites. NYSDEC is currently evaluating a Maximum Contaminant Level (MCL) recommendation of 1 µg/L for 1,4-dioxane from the New York Drinking Water Quality Council. If adopted, it would be the nation’s most stringent drinking water standard for 1,4-dioxane. The objective of this research was to develop and evaluate a cost-effective, low-maintenance 1,4-dioxane treatment technology for small-scale Point of Entry Treatment (POET) systems. The study was accomplished by conducting bench- and pilot-scale tests at the U. S. EPA T&E Facility in Cincinnati, Ohio, on 1,4-dioxane-spiked tap water. Based on the bench-scale testing, the pilot-scale testing focused on mixing ozone and hydrogen peroxide (peroxonation) was very effective in destroying 1,4-Dioxane in water. By using a combination of approximately 3.5 mg/L hydrogen peroxide and 5 mg/L ozone, water flow rates up to 10 gallons per minute (gpm) containing up to 200 µg/L 1,4-dioxane were treated. Influent 1,4-dioxane concentrations of approximately 10 µg/L, 20 µg/L, 80 µg/L, and 180 µg/L were reduced to effluent 1,4-dioxane concentrations of approximately 0.4 µg/L, 0.7 µg/L, 5 µg/L, and 10 µg/L, respectively, when treated at flow rates of approximately10 gpm.