Waste Management Strategies
It’s no secret — America’s disposable society has created a landfill crisis. Landfills around the country are approaching capacity, and new sites are difficult to approve.
Portland, Ore., however, is on the right track with an innovative solution. The city has created the nation’s largest composting facility for municipal solid waste.
In April 1991, a unique public/private partnership was struck between the Metropolitan Service District (METRO), a regional waste-management agency serving the metropolitan Portland area, and Riedel Environmental Technologies, an international environmental services company. METRO handles the actual composting process, while Riedel markets the finished product.
Several communities around the country have started composting programs for yard debris and sewage sludge, but only a handful process everyday household garbage.
“It’s the first municipal solid waste composting program of this size,” said Bob Martin, METRO’s director of solid waste. “We can handle 185,000 tons of garbage per year.”
The system currently can handle about 15 percent of Portland’s trash output. Future expansion is dependent on Riedel’s ability to find more customers for the compost, he said.
That, however, shouldn’t be a problem. Riedel already has sold more than three years worth of compost in advance, Martin said. And these sales occurred under contract terms stating the firm is not allowed to compete with METRO’s other compost products — yard waste and sewage sludge — within a 35-mile radius of the city.
One of the keys to marketing the compost is its quality. If it contains too many impurities — inorganic materials such as glass, plastic and heavy metals — it has limited applications.
“That’s why we’re doing a lot of the separation at the front of the system — before we try to compost the organic content of the waste stream,” Martin said.
A system of conveyors moves the trash through the facility. Employees then sort out the inorganic matter, leaving the remaining material to be dropped into a huge composting vat.
Even though municipal composting is a promising alternative to more landfills, households and businesses still need to reduce their demands on municipal garbage systems, Martin said.
“The key for most municipalities is to pass the real cost of disposal on to the people,” he said. “It costs $68 per ton to drop waste at our facility. At that price, a lot of commercial establishments will find better things to do with certain kinds of materials than just throw them away. Once you’ve done that, you’ve created a large incentive for people to recycle and avoid creating waste in the first place.”