Separating the elements
For four years, Hutchinson, Minn, has been composting yard waste and selling the resulting specialty soil products to gardening stores in five states. In 2006, the facility turned a profit for the first time, generating revenue for the town of 14,000 residents. The operation has been so successful, municipal officials from as far away as Australia and Japan have visited the town to learn how it operates. “I know we’re fairly unique in Minnesota,” says Doug Johnson, site coordinator at the Hutchinson composting facility. “Very few places offer the one-stop aspect that we do.”
CreekSide Soils, the compost facility, takes green waste directly from communities and homeowners; sorting, screening, composting and mixing it to produce its 29 different varieties of bagged garden material, from potting soil to colored mulch. In total, the 24-acre facility processes 30,000 tons of material each year, ranging from the town’s 2,500 tons of source-separated green material to bulky brush and logs from surrounding cities, and cow manure from local farms.
About five years ago, the facility bid to process approximately 24,000 tons of bagged green waste from Minneapolis. “We knew we needed the bagged material from the city’s curbside collection for our volume to be economical, so we went out and won the bid,” Johnson says.
But then, CreekSide needed to find an efficient method of processing up to 150 yards per hour of bagged material from the city. Crews first attempted to break down the material by grinding it, but that created airborne plastic that blew through the site, compromising the finished product. Next, it tried a debagger and a trommel, a rotary cylindrical screen that separates materials of different density. However, managing the plastic was still a problem, and the system fell short of CreekSide’s production goals.
So, the facility contracted with Peterborough, Ontario, Canada-based McCloskey International to custom-build a single-unit debagging trommel, which it began using in 2005. “The bags came through the trommel 99 percent clean; clean enough to be [composted and] marketable to recyclers,” Johnson says.
The new equipment now is finishing all the work that previously required two screening plants, so CreekSide is saving the rental cost of a second machine, and the residual plastic is now a recyclable commodity instead of waste. Labor costs are down, too, as the screener can be run by a single operator, and material is finished on the first pass.
When the machine is screening unbagged brush, it will process up to 60 semi-truck loads a day. It also speeds up leaf processing. “Screening the fall leaf pickup was taking us from October through to May,” Johnson says. “Last year, when we were still using two screeners, we were able to get it finished in January. But now, we can keep up as the material comes in.”
Project: Compost equipment upgrade
Jurisdiction: Hutchinson, Minn.
Agency: CreekSide Soils
Vendors: Peterborough, Ontario, Canada-based McCloskey International