Evoqua Water Technologies LLC (“Evoqua”) petitions the Environmental Appeals Board (“Board”) to review a Resource Conservation and Recovery Act (“RCRA”) permit (“Permit”) that the U.S. Environmental Protection Agency Region 9 (“Region”) issued to Evoqua and the Colorado River Indian Tribes (“Tribes”). The Permit governs the treatment, storage, and disposal of hazardous waste at a carbon regeneration facility operated by Evoqua on land beneficially owned by the Tribes near Parker, Arizona. Evoqua challenges the Region’s Permit decision on nine separate grounds.