Jepson Prairie Organics

This tour will take us to the Jepson Prairie Organics facility just outside of Dixon CA (southwest of Davis) where food waste from San Francisco and plant waste from Dixon and Vacaville is composted. Following that, we will visit Eatwell Farm, situated between Winters and Davis, one of the places Jepson Prairie Organics’ compost is used.

Friday June 13 at 8:30, step right up and sign in please. We met in front of the Ferry Building and were obliged to check in and sign an accident/injury waiver for the trip. Closed toed shoes were required; sun hats, sunglasses, sun screen and water were strongly advised, as we were anticipating a sunny day and nearly 100 degrees where we’re going.

On the way to Jepson Prairie Organics, Julie Cummins, the Director of Education for CUESA explained the Waste Wise Initiative at the Ferry Plaza Farmers Market.

The program has been wildly successful since it’s start on Earth Day, in April. Having a captive audience, she also stressed the need for volunteers for that program, and acknowledged the sponsorship of, among others, Coach 21, the bus upon which we were riding.
Off the bus, we found a beautiful day, not totally hot and with a light breeze, but gnats. We were told that normal days are hot and very windy, but the wind keeps the gnats away.

We reconnoitered in the Jepson office, where Greg Prior explained the composting process and some of the byproducts of composting, which they’ve adopted over the years.

Before the food waste is processed for composting, it is put through a process of anaerobic bacterial decomposition, producing methane. The methane is burned to produce electricity, enough to power Jepson’s facility with some left over. They are in the process of replacing their diesel-powered equipment with electric powered, a process that will take time, as electric powered equipment that they need is slowly becoming available.

The box of SunX packets on the counter, takes care of the sun, AND the gnats, so they say.

The composting process begins here. On the left, food waste or plant waste is dumped into a hopper and tipped onto a conveyor to the rotating drum with four-inch openings. The smaller material goes up the conveyor to the pile in the center.

Material larger than four inches goes up the conveyor into the blue shed on the right. There, unsuitable material — mainly plastic bags — is picked out and dropped into the containers below, to be hauled to the land fill on an adjacent site.

The guys in the shed are hand sorting. “Must be pretty uncomfortable in there,” somebody remarked. Our tour leader, Mark, said, “They’re okay, they’ve got a radio.”

The good material passes through the shed and onto another conveyor to the high-speed crusher (center), then up yet another conveyor to be deposited on the pile in the foreground. That’s moved by front-end loader to join the other material.

This is the plant waste, made into rows to aerobically decompose into compost, taking up to 90 days.

This is food waste, covered with “compost-tex” to reduce emissions.* The capacity of Jepson’s operation is limited by emissions allowed for the property. They are phasing in a new process where underground pipes draw air through the composting material and filter it. This will reduce emissions even further, hence increasing the capacity of the operation.

*NOTE: The compost-tex replaced the “Ag-bag” process mentioned on Jepson’s web site.

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The water truck on the left sprays the rows with water, which has been treated with microbes and other swell organic goodies. The machine following works the water into the material with an action much like a rototiller.

Travis AFB is nearby, The Jepson facility is situated perfectly for the flight path to the airbase. Big planes passed overhead every five or ten minutes. As a newly commissioned Navy Ensign, I flew out of Travis AFB in the early 60’s to join my ship, the USS Tulare (AKA 112) in Okinawa. That is a long flight. I read Lolita by Vladimir Nabokov, cover to cover, on the flight.

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Finally, at the front of the property, near where our bus parked, piles of compost — in various mixes — await shipping to their destinations, one of which will be Eatwell Farm, about 30 minutes to the north.