National Biosolids Land Applier to Pay $610,000 for Overapplication
First Clean Water Act biosolids judicial settlement with Denali Water Solutions, LLC holds company accountable for biosolids violations
WASHINGTON – Today, November 12, 2024, the Environmental Protection Agency announced a settlement agreement with Denali Water Solutions, LLC, of Russellville, Arkansas, for alleged Clean Water Act violations related to the overapplication of sewage sludge, also known as biosolids on land in Arizona and California. Under the settlement agreement, Denali will pay a $610,000 civil penalty. Additionally, the company is required to follow strict application requirements if they resume land application in these two states within the next five years.
Denali applied sewage sludge derived from municipal wastewater treatment facilities on the land, also known as biosolids. Clean Water Act regulations require biosolid producers and land appliers to collect pollutant data before applying biosolids to land. Land appliers are further required to apply biosolids at a rate that limits the amount of nitrogen to what the crop can use.
“Denali defied the law by repeatedly overapplying biosolids in California and Arizona, including on fallow land,” said 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.”
EPA alleges that, since at least 2016, Denali repeatedly (1) land-applied biosolids to land application sites in Arizona and southern California at levels that exceeded the nitrogen needs of the crops, and (2) failed to obtain the information necessary to determine the correct amount of biosolids to apply. The overapplication of biosolids can lead to nitrogen and other pollutants migrating into groundwater or running off into nearby surface waters.
Excess nitrogen in drinking water can be harmful to human health, particularly infants and young children. In surface waters, too much nitrogen can lead to the overgrowth of aquatic plants, increased harmful algal blooms, decreased light penetration, and reduced levels of dissolved oxygen. Each of these conditions makes it difficult for fish to live and people to swim.
In mid-2024, Denali ceased operations in Arizona and California. However, if the company land applies biosolids in these states within the next five years, the settlement agreement requires Denali to follow a specific “Soil Sampling and Agronomic Rate Calculation Protocol.” This includes sampling soil in the fields where Denali will apply biosolids and performing site-specific calculations to determine the appropriate amount of biosolids it can apply to those fields for crop use, minimizing risk of groundwater and surface water contamination.
This is EPA’s first judicial settlement against a biosolids land application company that solely addresses alleged Clean Water Act biosolids violations.
The proposed consent decree was filed in the U.S. District Court for the District of Arizona. The consent decree is subject to a 30-day comment period. Information on how to provide comments and a copy of the proposed consent decree are available on the Justice Department’s Proposed Consent Decree webpage.
More information on this enforcement action is available on EPA’s Denali Clean Water Act Settlement Summary.
Learn more about EPA’s Biosolids program.
Learn more about EPA’s enforcement of the Clean Water Act.