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)

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)

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

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.