September 10th, the City of Kingman made public the current status of the vadose zone injection well. As reported exclusively by the Mohave Free Press in the “Picture This!” column in our January issue, the City had been dumping millions of gallons of treated wastewater effluent on to the desert to evaporate and be swallowed by free range cattle, despite drilling a $1M+ well designed to help recharge the local groundwater basin. While construction on the well is complete, and discharge authorization has been granted by the Arizona Department of Environmental Quality (ADEQ), the well has not been put in operation.
While the City has met all regulatory requirements for effluent discharge, staff took the additional step of testing for drinking water regulatory requirements before moving forward. The test results showed that highly dangerous perfluoroalkyl and polyfluoroalkyl substances, also known as PFAS, levels were higher than those allowed in drinking water, as set by the U.S. Environmental Protection Agency (EPA) to protect public health. Because PFAS do not easily break down, they are sometimes called “forever chemicals,” and federal and state agencies have recently set new drinking water standards for them.
“At the time of construction, neither EPA nor ADEQ had finalized PFAS standards for drinking water,” said City Manager Tim Walsh. “Since then, standards have been adopted, and we are taking the extra step of applying those standards to our operations to protect Kingman’s groundwater.”
Two rounds of sampling from the City’s wastewater effluent showed PFAS results at or above drinking water maximum contaminant level (MCL). Because of this, City staff have made the decision not to discharge into the aquifer well at this time. Instead, the City is currently evaluating advanced filtration options designed to remove PFAS before discharging into the aquifer. The City will continue to work with ADEQ, EPA, and technical experts as it evaluates treatment options.