People power

GELLERMAN: It’s Living on Earth ? I’m Bruce Gellerman. Coming up, “Drill baby drill” ? but not for gas or oil. First, this note on emerging science from Sandra Larson.

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LARSON: “Waste not, want not.” The water department of San Antonio, Texas certainly takes that adage seriously, and keeps finding creative ways to reuse what residents flush down their toilets.

San Antonio Water System, or SAWS, already recycles liquid from sewage to use in landscaping and manufacturing; some of the solids go into compost. And now they’re going to reap other benefits from the sewage by harvesting the methane gas generated by solid waste, and selling it as fuel.

SAWS recently signed a deal with Ameresco, a Massachusetts-based energy services company. Ameresco will build and operate a new facility in San Antonio to capture some million-and-a-half cubic feet of methane a day. They’ll sell the gas to power companies, and pay a royalty to SAWS.

Methane from the city’s sewage is normally burned. Now, instead of going up in smoke, the gas is expected to earn about 250,000 dollars a year for SAWS. That means better air quality, lower operating costs, and lower water bills for ratepayers.

Other communities already capture methane from animal waste or landfills; some even use human waste to power sewage treatment plants. But San Antonio will be the first US city to convert its sewage to methane on a large scale and sell it as energy. When the facility opens, San Antonio will be recycling more than 90 percent of its human waste ? giving a new meaning to people power.

That’s this week’s note on emerging science. I’m Sandra Larson.