System could revolutionize small-town garbage woes

Large-scale composting system could cut volume of garbage by two-thirds

Posted: Tuesday, April 22, 2003

HAINES - A new garbage composting system here is being watched closely by small towns around the nation as a possible solution to solid waste disposal.

Haines Sanitation's "in-vessel" composting system is still a few weeks away from full operation, but has the potential to reduce by two-thirds the volume of garbage and sewage sludge buried at the landfill, company president Lynda Walker said. Eventually, it also will produce salable compost.

The composting system should be able to handle twice the company's average current volume of 3 tons of trash per day.

"We built it for the future, not the short term," Walker said.

Alaska Department of Environmental Conservation solid waste regulator Ed Emswiler said in-vessel composting could be used for sewage sludge and garbage disposal in Bush Alaska, where other options are limited.

"Typically, we deal with solid waste by burning it, shipping it or sticking it in a hole in the ground," he said. "This is new, and they're taking a big risk. But it has the potential for solving a lot of problems."

Walker and partner Tom Hall say the new facility amounts to a large-scale, mechanized version of a backyard compost pile.

Equipment includes two 40-foot-long, 15-foot-diameter rotating drums. One prepares a mixture of garbage, sludge from the city sewage treatment plant and water. The second separates material after it "cooks" in four shipping-container-size composting vessels.

After being mixed, waste is placed in the sealed composting vessels, which are injected with air to initiate digestion. Compost is created when the mixture cooks for three days at 165 degrees, reducing the overall volume and destroying biological pathogens. Air and liquid byproducts are filtered and cycled back into the vessels.

The compost is screened and separated from inorganic material in the second drum. The uncomposted material will be taken to the landfill and covered with the compost.

Walker and Hall are adjusting the mixture of materials, including wood chips and sawdust, to tune the system's operation.

Haines Sanitation's customers will be asked to separate inorganic waste, such as metal, scrap lumber and other building supplies, sheet plastic and some other items from their household trash. Glass, paper products, food waste and most other household garbage can be processed in the system.

Walker doesn't envision raising rates above the average $42.50 per month for residential customers and doesn't expect a municipal takeover of the private system.

"We certainly didn't build it with that in mind," she said.

The company's aim is to reduce landfill use and eliminate reliance on shipping garbage Outside for disposal, which is expensive.

"It's money that should be staying here and paying for this instead," Walker said.

The system cost about $300,000. The U.S. Department of Agriculture and the Juneau Economic Development Council's Southeast Alaska revolving loan fund provided the financing.

Minnesota composting expert Jim McNelly helped design the system. McNelly, whose company NatureTech pioneered in-vessel composting in larger towns, said Haines Sanitation's success would be groundbreaking.

"The intent here is to make the case that this kind of program is the best way to manage municipal solid waste in small communities," McNelly said. "There are a lot of people watching this project. It's under a rather large magnifying glass. If we show that this can be done in Haines, it can be done in rural communities all over the world."

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