A pair of environmental groups filed suit Thursday to block a proposed Kahului sludge farm and power plant.

The Sierra Club Maui Group and Maui Tomorrow are challenging an environmental impact statement prepared by Anaergia Services, the organization behind the new project, and approved by the county environmental management director.

The proposed project would transport sludge from wastewater treatment facilities at Kihei, Lahaina and the Wailuku-Kahului Wastewater Reclamation Facility to a cite at the Kahului wastewater facility and dried using methane gas byproducts produced by the anaerobic digestion of “biocrops” grown on former sugar cane land (with supplemental energy from a propane burner). The process also would produce electricity for the facility.

The groups said they object to Anaergia’s preparation of the EIS in part because of a supposed unwritten county policy by which projects that have an EIS prepared by an entity outside the county are subject to less strict oversight.

The groups also claim that the statement does not adequately account for sea-level rise prediction.

“Maui County needs to move forward, not backward, by getting the Kahului treatment facility out of the tsunami zone and away from sea level rise,” said Maui Tomorrow Executive Director Albert Perez.