A design-build contract for a $6.8-million solar project to help power a wastewater treatment plant in Bakersfield, Calif., could see the light of day because of a proposed $3-million federal stimulus grant.

Photo: Bakersfield Public Works

Funding will come from federal stimulus grant and utility, municipal sources.

The American Recovery and Reinvestment Act (ARRA) funds will cover 44% of the cost of a 1-MW single axis photovoltaic tracking system on a 5-acre site adjacent to Wastewater Treatment Plant No. 3, with room to expand.

“The stimulus funds were a significant factor in making the numbers pencil out,” said Art Chianello, Bakersfield Public Works wastewater manager. “We would not have built the solar portion of the project without the [Energy Efficiency and Conservation Block] grant.”

The balance of the funding will come from San Francisco-based Pacific Gas & Electric’s solar incentive rebates and city funds.

The design-build contract will go to bid as soon as the stimulus funds are officially granted and would take six months to complete.

The solar component will act as a secondary power source to an onsite cogeneration plant, which uses digester gas from the anaerobic solids processing at the treatment plant to create energy. The increased power generation is required to offset the demand that will be created once capacity is expanded from 16 million gal per day to 32 mgd.

“We wanted to offset the power deficit that would be created,” Chianello said. “In sunny Bakersfield, solar just makes sense.”

Parsons Corp. designed the expansion so it could eventually accommodate 64 mgd with an initial 30 mgd in percolated treatment on site and in agricultural uses. Another 2 mgd will receive tertiary treatment and be reused for irrigation.

Kiewit Pacific Co. began construction on the $211-million expansion in September, 2007. It will be complete in 2010. Features include a 40-mgd off-site pump station a new headworks, conversion of four secondary clarifiers into primary clarifiers and conversion of two trickling filters into organic media biofilters.

The Bakersfield project would be part of the $467 million in ARRA funds for geothermal and solar projects being distributed by the Dept. of Energy. More than $40 million will be focused on solar deployment, particularly in cities to save money going forward while creating green jobs.