The Environmental Protection Agency (EPA) has announced a settlement with Denali Water Solutions, LLC, based in Russellville, Arkansas, for alleged violations of the Clean Water Act. The company is accused of overapplying sewage sludge, known as biosolids, on land in Arizona and California. As part of the settlement, Denali will pay a civil penalty of $610,000 and must adhere to strict application requirements if it resumes land application in these states within the next five years.
Denali was involved in applying biosolids derived from municipal wastewater treatment facilities onto land. Regulations under the Clean Water Act require producers and appliers of biosolids to collect pollutant data before application and to apply them at rates that match the nitrogen needs of crops.
"Denali defied the law by repeatedly overapplying biosolids in California and Arizona, including on fallow land," stated David M. Uhlmann, Assistant Administrator for EPA’s Office of Enforcement and Compliance Assurance. "This settlement demonstrates once again that EPA will hold companies accountable when they put profits over protecting public health and the environment."
The EPA alleges that since at least 2016, Denali applied biosolids at levels exceeding crop nitrogen needs in Arizona and southern California without obtaining necessary information to determine appropriate amounts. Such overapplication can result in pollutants like nitrogen entering groundwater or running off into surface waters.
Excessive nitrogen poses risks to human health, especially for infants and young children if present in drinking water. In surface waters, it can cause harmful algal blooms and affect aquatic life by reducing oxygen levels.
Denali ceased operations in Arizona and California by mid-2024. However, should they resume biosolid applications within five years, they are required by the settlement to follow a "Soil Sampling and Agronomic Rate Calculation Protocol." This involves soil sampling and specific calculations to ensure safe application rates for crops while minimizing contamination risks.
This case marks the EPA's first judicial settlement addressing alleged Clean Water Act violations specifically related to biosolids land application. The proposed consent decree has been filed with the U.S. District Court for the District of Arizona and is open for a 30-day public comment period.
Further details about this enforcement action can be found on EPA’s Denali Clean Water Act Settlement Summary page.
