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Every day, hundreds of tons of food are thrown away in San Mateo County. Not composted—thrown away.
“The reality is people aren’t very good at separating food waste,” said Hilary Gans, senior facilities manager at the waste management authority RethinkWaste. Organic waste makes up a third of all garbage collected in the county, he said: more than any other category. All that tossed food piles up in landfills, where it decomposes and releases harmful methane gas into the atmosphere.
A new device, however, could pull those numbers way down. It’s a big, green, $5 million machine called an OREX.
“It’s kind of like a garlic press,” Gordon Tong, program director of waste reduction at the county Office of Sustainability, said of the device, adding, “except all the stuff that oozes out of it is organics.”
Basically, he said, you load up the OREX, or “Organic Extrusion Press,” with garbage, and it separates out the organic waste — the food and compost — from everything else.
RethinkWaste approached the county last October with the idea, Tong said. The Board of Supervisors then approved a $1 million grant toward a pilot program to try the device for six months to a year. The pilot, which is slated to begin next January, will use the OREX to extract 50 to 75 tons of organic matter per day, according to a county press release.
If the pilot is successful, the release continues, it could lead to a “larger scale project with the capacity to extract an estimated 200 tons per day of organic material from the landfill waste stream.” That’s a 16% increase in the food waste that will be diverted from landfills, Gans said — almost 10 tractor trailers each day.
But keeping that food waste from the dump isn’t the only benefit, he explained. The extracted organic waste, in the form of a liquid slurry, will be sent to a wastewater treatment plant in Redwood City, where it will be converted into biofuel.
In other words, Gans said, “It’s a double win. You’re getting clean energy and you’re avoiding [pollutants].”
The biofuel from the OREX extract will have zero net emissions, and can be put to a number of uses, Tong said. During the pilot, the fuel will be used to help power the wastewater plant. But if the project scales up, it could also be used to power waste collection trucks throughout the county, he added.
“It’s a big win for us,” said Tong, “not only in the solid waste sector, but also in the climate change mitigation sector.”
This two-pronged process — extracting organic waste, then turning it into biofuel — will be the first project of its kind. While both parts have been done elsewhere in isolation, RethinkWaste will be the first to do them together, Gans explained.
“You’d think it would be happening all over, but it’s not,” said Gans. “It’s a great chance to marry these two industries for the benefit of the ratepayers and the environment.”
RethinkWaste is now obtaining the device, and plans to begin testing it in December.