New Seattle law will cook restaurant waste into compost

Piles of deep, dark compost sit in rows, 12 feet tall, cooking and cooking some more until it is ready to be sold and planted in gardens.

Here at Cedar Grove Composting in Everett, it's hard to believe the rows of compost were once tree limbs, food waste and even paper plates, all items dumped in residential and commercial compost bins.

As of Thursday, Cedar Grove's business might explode when Seattle begins its ban on all throwaway single-use service ware; all the takeout service ware — containers, plates and cups — sold in fast-food restaurants, must be compostable. Already it's in place at Safeco Field.

About half the restaurants in Seattle, about 1,700 total, have signed up for food-waste collection by Cedar Grove, according to Seattle Public Utilities spokesman Dick Lilly.

Before, most of that service ware went into the garbage. And the food itself went down the drain.

"This used to go down a large disposal, which was very water intensive," Lilly said, "Now it's in a food-waste Dumpster taken to Cedar Grove."

The new law means 6,000 more tons of leftover food and containers will be recycled and composted from fast-food restaurants alone.

Cedar Grove, located off Interstate 5 north of Everett, accepts nearly 700 food-service packaging items, many added in the past two years. It is one of the largest commercial composters in the country.

Cedar Grove has two plants. The first was built in Maple Valley in 1989 and the Everett facility in 2004. It accepts food and yard waste from all cities in King County and part of Snohomish County.

Cedar Grove is a recycler, manufacturer, wholesaler and retailer of compost. Some is sold to nurseries, some to Department of Transportation projects. Most is sold in bulk to dealers, said Susan Thoman, director of corporate business development. But homeowners also are customers and Cedar Grove sells a variety of compost, from topsoil to vegetable garden soil. Thoman said the average load sold is 10 to 15 cubic yards of compost.

During the busiest time of the year 100 to 150 trucks will make daily deliveries to Cedar Grove, said Thoman. The waste will produce as much as 1,000 tons of compost a day.

And there are seasons: April is grass season; December is Christmas tree season; November is pumpkin season. May is usually the busiest month at Cedar Grove with the start of the gardening season, but that was pushed back with this year's cold spring.

Stewing the compost is a slow, complex process. The waste is ground, put in rows and covered with a Gore-Tex-like material. It sits for three to four weeks, with a fan underneath blowing in oxygen to aid the process.

Then the compost is moved to another pile, where it sits covered for another two weeks. In the third phase, the compost is uncovered. That whole process takes eight weeks, depending on the time of year. And then it sits to darken up and takes from four to 12 weeks to age before it is sold. Stuff that can't be composted, like nails, aluminum cans and even tennis balls must be separated from the mix.

Cedar Grove is locally owned by the Banchero and Malshuk families, who have a long history in waste collection. In its 20 years, Cedar Grove has invested more than $40 million in land, equipment, technology and expertise to develop its composting facilities.

Cedar Grove is licensed to process 228,000 tons a year on its 26-acre Everett campus.

The biggest change coming to Cedar Grove is plans to convert food and yard waste into green energy through a biogas. Cedar Grove says it can produce enough electricity and natural gas to heat 400 homes and provide fuel for 1,100 vehicles.

Susan Gilmore: 206-464-2054 or sgilmore@seattletimes.com