The $160M question: Is upgrading Kealakehe sewer plant to R-1 worth it?

Duckweed grows on the holding ponds at the Kealakehe Wastewater Treatment Plant. (Laura Ruminski/West Hawaii Today)

Waste water is treated in holding ponds at the Kealakehe Wastewater Treatment Plant. (Laura Ruminski/West Hawaii Today)

R2 water is pumped into a secondary disposal site across from the Kealakehe Wastewater Treatment Plant on Wednesday. (Laura Ruminski/West Hawaii Today)

Kealakehe Wastewater Treatment Plant distribution system. (courtesy Hawaii County Department of Environmental Management)

Mayor Mitch Roth’s top environmental official is taking a hard look at the advisability of upgrading Kealakehe Wastewater Treatment Plant to produce R-1, the highest grade of recycled water, after the cost of the 20-year-old plan ballooned to $160 million.