Composting Facility Fights Smells, Boosts Productivity

Fri December 21, 2007 - Midwest Edition
April Goodwin



Composting facilities often must battle scents associated with their operations, but when a multimillion dollar housing development is built within a mile of a composting facility, the challenge becomes an all-out war with aromas.

“We live or die by our grinder because if we can’t get material ground as it comes in, we get complaints,” said Dave Rettell, general manager of the Onyx Arbor Hills Compost Facility.

Ten years ago, the Onyx Arbor Hills Compost Facility in Plymouth, Mich., had between five and 20 neighbors within olfactory range. In recent years, a community of more than 200 executive-style multimillion-dollar homes has sprung up, Rettell said.

The Onyx Arbor Hills Compost Facility recently purchased a new tub grinder after deciding that the current grinder wasn’t keeping pace with demand. Rettell said after exploring several options, he settled on a Vermeer TG9000 tub grinder because it was competitively priced and its high productivity level left room for the operation to grow.

“Our other grinder was older and smaller, and it couldn’t keep up — so we had to stockpile waste, which created an odor,” Rettell said. “But with the new grinder, we can get everything ground the day it comes in.”

The Vermeer TG9000 tub grinder is designed for contractors who are involved with large land clearing projects and organic- or wood-processing facilities. The 800 or 1000 hp (596 or 745.4 kW) units feature a PT Tech wet clutch, and are microprocessor-controlled with built-in torque limiting. They are built for contractors looking for more power and higher tub-grinding production.

The facility uses the TG9000 eight hours a day, five days a week to grind green waste including brush, leaves, trees and grass.

The Onyx Arbor Hills Compost Facility processed approximately 400 tons (362.8 t) per day in June 2004. In the fall, the busiest time of the year, the facility will handle up to 800 tons (725 t) of waste per day, Rettell estimated.

Customers include third parties such as landscaping contractors and waste management companies. The Onyx Arbor Hills Compost Facility also is contracted to handle one-third of the Western Township Utility Authority’s waste.

The site was developed 10 years ago and is built upon 2 ft. (.6 m) of re-compacted clay and a compacted limestone top. Waste is weighed and unloaded onto the limestone pads when it’s brought into the composting facility. Then it’s picked up with front-end loaders and processed in the Vermeer TG9000 tub grinder.

The processed green waste is hauled by trucks to the composting area and piled in 7-ft. tall (2.1 m) windrows that stretch 800 ft. (243.8 m) long. The green waste will remain in the windrows for three to four months to cook before it is placed in a cure pile, being turned regularly. Then, it sits in the cure pile for approximately two more months before it is screened.

Any material too large for screening is inspected for non-biodegradable products, which are removed and disposed of with the remaining green waste placed back into the windrow pile.

The end product is sold in bulk to landscape contractors. The Michigan Department of Transportation also purchases compost to use or sell for roadside landscaping and planting applications.

The composting facility was built in 1995 after Michigan legislators passed a law restricting yard waste from entering landfills. Rettell was a lead engineer on the project. In 2000 Onyx, a worldwide leader in composting, purchased the facility along with several transfer companies and hauling stations.

“We are one of a handful of compost facilities in the Detroit area,” Rettell said. “It’s definitely a viable business because of where we’re located. But being so close to metro Detroit is also one of our downfalls because we’re dealing with more and more neighbors … That’s why the Vermeer TG9000 tub grinder is so important to us — because we need to process everything the day it comes in to avoid producing a stench.”

(April Goodwin is a technical writer.)