Kaua'i County officials have issued a request for proposals to expand the Waimea wastewater treatment plant.

County Engineer Donald Fujimoto yesterday said the project is expected to cost about $12 million.

He said $7 million is coming from federal stimulus money, with the balance financed through the county's capital improvement program.

The plant was built in the 1970s and has a capacity of 300,000 gallons per day. It is currently operating at 90 percent capacity. Because it is near capacity, the county is restricting new sewer service connections in the area.