In 2015, the City of St. Anthony Village discovered 1,4-dioxane in its three municipal wells. The wells helped provide over 9,000 residents with drinking water, and the city partnered with WSB to quickly address health concerns related to the contamination. The city’s water treatment plant was outfitted to treat the contaminant with ultraviolet (UV) light and hydrogen peroxide (H2O2) technology. We partnered with the city from initial planning to full operation, providing additional services in grants and funding and community outreach.
The water treatment plant is the first plant in the state of Minnesota to use UV light and H2O2 to treat drinking water. At the beginning of the project, we studied several Environmental Protection Agency (EPA) reports on methods for treating 1,4-dioxane and concluded that the contaminant could be treated with UV light and H2O2. 1,4-dioxane is an organic compound that is not fit for human consumption and can create health concerns. Several modifications were made to the existing water treatment plant to accommodate the change to UV light and H202.
During planning, we identified several options to address the contamination, including constructing new wells and purchasing water from nearby cities. None of the other options were as cost-effective for the city and its residents as treating the contaminant with UV light and H2O2. When added to water, H202 absorbs UV light, producing hydroxyl radicals that break the contaminant down into nontoxic compounds consisting of carbon dioxide, water, and residual chloride.
In addition to its cost-effectiveness, the use of UV light and H202 technology for water treatment offers several auxiliary benefits. The technology destroys and removes 1,4-dioxane from the environment and does not create byproducts that require disposal as hazardous materials. It cleans the aquifer, reducing risk to other users of the aquifer located downstream of St. Anthony Village. The technology is also effective in removing other, more severe contaminants from drinking water.