Formatted Title
TCE and 1,4-Dioxane AOP Treatment in Groundwater at New Brighton/Arden Hills Superfund Site, Arden Hills, Minnesota
Background/Objectives
The EPA designated the New Brighton/Arden Hills Superfund Site for the cleanup of elevated trichloroethylene (TCE) and later, 1,4-dioxane in the Site’s soil and groundwater. Since 1987, TCE-impacted groundwater in Operable Unit 2 at the facility (OU2) had been effectively treated by air stripping to meet the cleanup requirements. In early 2015, an emerging contaminant, 1,4-dioxane, was detected up to 6.8 micrograms per liter [µg/L]. The operation of the treatment system was temporarily ceased until a supplemental investigation could be performed and 1,4-dioxane treatment system could be designed and installed. The EPA targeted a 1,4-dioxane reduction from 100 μg/L to less than 1 μg/L and TCE reduction from 2500 μg/L to less than 5 μg/L and required bromate formation control to EPA’s MCL for drinking water to below 10 ug/l.
In March of 2021, as part of the FINAL EXPLANATION OF SIGNIFICANT DIFFERENCES #3 CHANGE IN GROUNDWATER TREATMENT SYSTEM AND ADDITION OF 1,4-DIOXANE AS A CONTAMINANT OF CONCERN, an advanced oxidation technology, UV with hydrogen peroxide, was originally selected as the treatment solution for the 1,4-dioxane post air stripper.
Approach/Activities
Arcadis evaluated Trojan’s AOP technology, UV with hydrogen peroxide, to treat the 1,4-dioxane and TCE in the remediation wastewater per the ESD. The concentrations of dissolved solids in the water samples reduced the transmissivity of the UV light through the reactor causing Arcadis to evaluate capital investment for pre-filtration equipment prior to the UV reactor. The capital cost and the potential that the pre-filtration would not be effective to improve the UV transmissivity caused Arcadis to look at alternative AOP treatment technologies. APT Water’s HiPOx technology, ozone and hydrogen peroxide, was evaluated and proved effective to destroy 1,4-dioxane and TCE without pre-filtration and capable of controlling the formation of bromate.
Results/Lessons Learned
Since February of 2023, the HiPOx treatment system has been treating and meeting the targeted discharge concentrations and effectively controlling the formation of bromate.
The presentation will provide information about the project as reviewed and approved by the Army. The information is expected to include site background and treatment objectives, bench test information for the evaluation of the treatment technologies, specific challenges imposed by the remediation wastewater at the site on each technology (low UV T, bromide concentrations, etc.), a comparison of the capital and operational costs for each technology, and treated sample results for the selected technology, HiPOx, expected to be available at the time of presentation.