Case Study: City of Rialto, California
Wastewater Treatment Plant

Background
Rialto, California, a city of about 100,000 residents, lies sixty miles east of Los Angeles in one of the nation’s fastest growing regions. Faced with forecasted population growth and an aging water treatment system, the city needed to expand and modernize its municipal water treatment facility.

Solution
The City of Rialto selected Chevron Energy Solutions (CES) to engineer and construct a system to transform wastewater sludge and kitchen grease from local restaurants into clean, renewable power at its wastewater treatment plant. CES’s innovative design incorporates energy efficiency and renewable power and provides an environmentally beneficial solution for the disposal of fats, oils and grease (FOG). The new system includes a 900-kilowatt fuel cell power plant to provide 24-hour baseload power to the facility, a FOG receiving station, repairs to the current digester equipment, a new automated controls system, and a high-efficiency boiler. The project is scheduled for completion in 2009.

The fuel cell power plant consists of three 300-kilowatt units. The fuel cells convert methane to hydrogen which in turn generates electricity through an electrochemical process, without combustion or pollution. The methane (or biogas) is generated on-site in the wastewater sludge digester tank. FOG collected at the receiving station is added to the digester to increase biogas production. Waste heat from the fuel cells is used to warm the wastewater sludge inside the digester to stimulate optimal methane production.

The fuel cells are manufactured and will be maintained by FuelCell Energy. With its low-emission profile, the new plant meets California’s stringent air quality standards.

The FOG receiving station provides an effective alternative for FOG hauling companies to dispose of the thousands of gallons of fats, oils and grease collected each day from restaurants. This disposal method reduces the amount of FOG delivered to landfill sites as well as the methane that would have been produced and released into the atmosphere during decomposition. It also provides new revenue for the City from the “tipping fees” paid by the grease hauling companies.

Benefits
The new system will decrease the city’s energy costs by about $800,000 a year, increase municipal revenues, reduce landfill waste, and lower greenhouse gas emissions by 11 million pounds of carbon dioxide annually, equivalent to removing 1,080 cars from the road each year.

The $15.1 million project cost was partially offset by a $4.05 million rebate on the fuel cell plant from California’s Self-Generation Incentive Program administered by Southern California Gas. The remaining project cost was self-funded through energy cost savings and FOG station revenues, without any impact on local taxpayers.

By looking at the wastewater treatment operations holistically, Chevron Energy Solutions developed, engineered and constructed a solution that delivers multiple benefits: urban waste transformed into an asset, renewable power and energy savings, and reductions in landfill waste and greenhouse gas emissions.

Back to Top