Airport Composting Project

FROM: DAN CORBIN at WISCONSIN WORM FARM

Worms to turn out compost at airport’s $1.1M recycling center
Wriggling waste-eaters are at heart of planned $1.1M recycling center.

Charlotte/Douglas International Airport is about to get a whole lot creepier. Crawlier too, in fact.

photo by Earth911.com
photo by Earth911.com

The airport is installing a worm-based composting system as part of a new $1.1 million recycling center, expected to open in February. Soon, hundreds of pounds of worms will be munching away on a ton or so of travelers’ trash a day, according to airport officials.

“We generate a lot of garbage here, and it’s incredibly expensive to collect it, haul it off and pay to dispose of it,” said airport director Jerry Orr.

The new composting system will be built to handle up to two tons of waste daily – enough to keep up with eventual airport expansion, officials said. The airport plans to spread the worms’ waste as fertilizer on its 6,000 acres, and package and sell the excess.

The compost materials, including food scraps, meat, bones, paper waste, bathroom towels and plant waste, will first be fed into a 1,600-square-foot pre-composter. There must be a system installed to control the odor, the airport’s bid documents say.

Once it’s partially broken down in the pre-composter, the waste will be loaded into the worm composting system.

The airport’s initial plan is to order 300 pounds of worms for $6,000. The worms’ home is expected to take up some 8,000 square feet, or around the size of an average Family Dollar store.

In the giant worm bin – the technical term for it is “continuous flow vermicomposting system” – the worms will eat their fill, leaving behind worm “castings,” as the crawlers’ excretions are politely known.

The castings will be harvested from the bottom of the worm composter. The worms will then crawl upward toward the fresh (to them) food.

Over the next five years, the recycling center as a whole is expected to save the airport about $1 million in waste disposal costs, paying for itself, officials said.

Money to build and operate the recycling center will come from the airport’s operating budget, mostly made up of fees paid by passengers and airlines. The center will also sort aluminum, plastics and paper and sell them to recyclers. The project will be overseen by a company called Go Green, which will hire about 10 employees to run it.

Rhonda Sherman, a vermicomposting specialist at N.C. State University, said she’s not aware of any other airports that currently have such a program, though Raleigh’s airport is considering one.

Charlotte’s city council will vote on the contract to build the worm-composting center on Nov. 14. Installation, in a building on Yorkmont Road, is slated for January.

A similar airport recycling plan was tried about 15 years ago, Orr said, but discontinued because it wasn’t economically feasible. Disposal costs have risen enough to make the project cost-effective now, Orr said.

Plan not without skeptics Ron Danise owns Union County-based Southern Organics, which produces more than 8 tons of worm castings a day. He’s not bidding on the project, and said he’s skeptical it will be as manageable as the airport thinks.

“It sounds good on paper, but I’m telling you, it’s not going to produce much,” Danise said. He’s skeptical of any system that gives worms food waste, and said that even under the best conditions, it takes worms nearly a month to process a load of feed.

“Worms are herbivores. … They don’t like a North American diet,” he said.
Airport officials said they’re confident the pre-composting process will break down the material enough for the worms to process food scraps.

Danise also cautioned that a large-scale worm-composting system comes with unexpected complications.

For example, Danise said that during strong thunderstorms he’s seen worms wriggling free from their bins en masse – what he calls a “crawl event.”

Orr admits that airport officials aren’t worm-composting experts yet, but said he believes the program will work.

“When you can do something that is good for the environment and make it self-sustaining, that strikes me as something we should pursue.”

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