Siemens, Chevron Energy Solutions help city turn waste to energy

The city of Rialto, CA, is working with Siemens Water Technologies to install two Dystor gas holder systems at the city's wastewater treatment plant. The Dystor systems, which are part of a comprehensive upgrade being designed and installed by Chevron Energy Solutions, will be used to store methane gas produced from treating municipal wastewater sludge and local restaurant kitchen grease. Rialto uses three 300-kW fuel cells to convert the biogas into hydrogen and to generate power...

• Dystor gas holder systems store methane from wastewater sludge

CHICAGO, IL, Oct. 20, 2008 -- The city of Rialto, CA, is working with Siemens Water Technologies to install two Dystor gas holder systems at the city's wastewater treatment plant. The Dystor systems, which are part of a comprehensive upgrade being designed and installed by Chevron Energy Solutions, will be used to store methane gas produced from treating municipal wastewater sludge and local restaurant kitchen grease. Rialto uses three 300-kW fuel cells to convert the biogas into hydrogen and to generate power electrochemically, without combustion, for the plant.

Increasing its biogas storage will help Rialto further reduce its energy costs, grow city revenues, and improve air quality. In addition, if the plant is able to operate its 900-kW fuel cell plant on 75% biogas by the end of the year, it will receive a significant rebate from California's Self-Generation Incentive Program.

Fast delivery and installation were key factors with the Siemens order. The first Dystor was installed last month and the second is due to be installed after the first of the year.

At 75-feet in diameter and 14-inches water column, both gas holder systems are the high gas take-off style. The high location of the gas take-off in this system configuration prevents any digester foam from reaching the gas piping. Additionally, the inner gas holder membrane is permanently fixed at the top so that it cannot extend very far into the tank when the system is out of service and deflated.

The city's public works department retained Hunt Environmental of Rancho Santa Margarita, Calif., as the project consultant for this waste-to-energy initiative. Over the years, Siemens and Rialto have teamed up on other water projects, including pure water production at the city's wastewater treatment plant and perchlorate removal from the city's groundwater.

The Siemens Industry Sector (Erlangen, Germany) comprises six Divisions: Building Technologies, Industry Automation, Industry Solutions, Mobility, Drive Technologies and Osram.

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