WAIMEA — The county recently issued a request for proposals for the expansion of the Waimea wastewater treatment plant.

The project is expected to cost approximately $12 million, with $7.5 million coming from federal stimulus money through the American Reinvestment and Recovery Act, and the balance to be financed through the county’s capital improvement program, a county news release says.

The stimulus funds available for the Waimea project are administered by the state Department of Health, and can only be used for projects that protect water quality and qualify under the state’s Water Pollution Control Revolving Fund Program.

“We are very pleased to receive stimulus funds for our island,” said Mayor Bernard Carvalho Jr. in the release. “I want to thank our Public Works staff for working closely with the state Department of Health to secure the money for a project that benefits the people of Kaua‘i.”

Noting the economic impact of the Waimea project, the mayor said, “One of the main ways to stimulate our economy is to get our construction projects out to bid so I’m happy that this project is moving forward.”

Proposals for the design/build contract to expand the Waimea WWTP will be accepted until Sept. 30, and the contract will be finalized prior to Nov. 30.

The project is expected to be completed approximately 18 months after the contract is executed.

Built in the 1970s, the Waimea WWTP serves most of the commercial and residential areas of Waimea Town, along with portions of Waimea Valley.

Treated R-2 effluent from the plant is used as an irrigation source for agricultural operations on the coastal plain between Waimea and Kekaha.

The Waimea WWTP has a capacity of 300,000 gallons per day, and is currently operating at 90 percent capacity.

Because the plant is near capacity, the county is restricting new sewer service connections in the Waimea community, which has hindered the expansion and development of several significant commercial projects in the area.

Earlier this year, the county completed a facility plan for the Waimea WWTP, which identifies the near-term need to double the capacity of the facility, and improve its efficiency and reliability.

Preliminary design work for the project is underway, and the Final Environmental Assessment was published in November 2008.

Among the improvements planned to modernize the Waimea WWTP are:

• Expand its capacity to 700,000 gallons per day.

• Upgrade key WWTP processes and conditions such as access road improvements and biosolids handling.

• Upgrade effluent water quality to meet the state Department of Health’s R-1 reuse standards in order to be able to use the treated water for irrigation purposes.

• Increase its backup effluent disposal capacity by drilling an additional injection well, and expand the monitor well network to ensure aquifer protection.

• Install a photovoltaic system to reduce the energy requirements associated with the plant expansion.

• Upon completion of the Waimea WWTP project, the following benefits will be available to the Westside community:

• Current restrictions on new sewer connections will be eliminated.

• Sewer capacity will be available for community development, including infill development of additional dwelling units and all other sectors of residential housing such as low-income housing projects.

• Large capacity cesspools could be converted to the sewer system.

• Irrigation systems for schools and parks could be converted to R-1 effluent water, freeing up potable water for higher value uses.