New Iao water treatment plan advances

Beginning next summer, Maui County hopes to begin work on a new $12 million to $15 million Iao water treatment plant that will nearly double the amount of water handled by the current plant, according to documents filed with the state.

Department of Water Supply Director Dave Taylor said the county is able to proceed with the project because of the recent Na Wai Eha settlement agreement on interim in-stream flow standards for Waihee, Waiehu, Iao and Waikapu streams.

In April 2014, parties in the Na Wai Eha contested case hearing, including community groups, Maui County and the Wailuku Water Co. (which owns the ditch system), agreed that 10 million gallons per day of ditch-diverted water would be returned to Iao Stream, from which the county draws water that is processed through the plant.

Currently, the existing treatment plant takes in 1.784 million gallons daily and produces 1.7 million gallons of drinking water, according to documents for the new plant. With the new facility and Na Wai Eha agreement, the county will be able to take on an additional 1.416 million gallons per day, Taylor said. Total daily output of the new treatment plant would be approximately 3.2 million gallons per day of treated water, according to documents filed with the state Office of Environmental Quality Control.

A finding of no significant impact has been determined for the project. It is planned for approximately 2.6 acres of vacant private property on West Alu Road near its intersection with Iao Valley Road and West Main Street, just mauka of the current treatment plant.

Construction is expected to take approximately two years. It would consist of a treatment plant building; an above-ground, 2,000-gallon diesel fuel tank as part of a generator system; a sludge lagoon; a chlorine contact tank; finish waterline; gravity wastewater line; and a drainage system.

When construction on the new plant is completed, the existing one will be decommissioned.

A new water treatment plant also is being built because the existing temporary membrane filtration units at the existing treatment plant no longer have shelter. They were initially sheltered within a large tent that has since been removed. The units have been exposed to the elements for a number of years.

Because of future population demands and a need for new treatment units, the county also decided to move ahead with the new plant, documents said.

Taylor added that the county also is proceeding with surface water use permit applications.

* Melissa Tanji can be reached at mtanji@mauinews.com.