Compressed Natural Gas Infrastructure at San Mateo's Waste Water Treatment Plant
Public Works

National Public Works Week: Sewage Becomes Fuel

National Public Works Week is May 21 through 27. This week we’ll be highlighting activities that the San Mateo Public Works Department is doing to make this community better for all residents. Visit San Mateo’s Public Works Department on the city’s website for more information about all they do.

Converting Sewage to Fuel

Did you know that the City’s Public Works Department is turning sewage into fuel for City vehicles?

This fuel is being created through a program at the wastewater treatment plant. When sewage is treated, the solids left behind are put into a digester for further treatment. This process creates an unusable gas that consists mostly of methane.

The City has installed equipment at the treatment plant that cleans this gas, resulting in a clean, compressed natural gas (called CNG) that can be used as fuel that is significantly cleaner burning than regular gasoline or diesel. The remnants of the cleaning process can be safely disposed of as compost.
Currently, three City vehicles are using CNG, with plans to put 35 to 40 more vehicles into service by 2020.

Not only does CNG help the City save on fuel costs, it also results in lower emissions and better air quality. Because of this, the City is now earning carbon credits from the U.S. Environmental Protection Agency and the California Environmental Protection Agency. These credits can be re-sold to provide income to the City and support this program.

The CNG project has been awarded a National Engineering Excellence Award and a California State Engineering Excellence Award by the American Council of Engineering Companies.

Keep reading throughout the week to learn more about what San Mateo’s Public Works Department is doing to make the community better for all San Mateo residents. Subscribe to San Mateo Insider to stay up to date about all that’s happening at the city of San Mateo.


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  • Reply Jim Mathews May 23, 2017 at 2:25 pm

    I have been a San Mateo resident for 66+ years and have always been so very glad our family moved here. This area has so many positive qualities that I am often reluctant to share them with folks from other areas who may want to move. But now, after reading about our new sewage treatment process, I may not be able to be keep silent much longer! May Heaven be at least somewhat nearly as good as San Mateo! 🙂

    • Reply San Mateo Insider May 23, 2017 at 2:30 pm

      Thank you so much for your kind comment, Jim! We appreciate it. It was exciting to see this project come to fruition.

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