When officials in Lee County, Fla., first announced plans to construct an energy-from-waste facility as part of a solid waste management program, the concept was met with considerable opposition from environmentally-conscious residents.
“There’s this idea that comes from a very personal and emotional level that burning garbage is bad. There are toxic emissions released into the air, etc. … and folks were understandably concerned,” said Lindsey Sampson, director of solid waste management for Lee County. “However, once they understood that the process meets and exceeds environmental standards while creating energy, that’s a concept everyone can get behind.”
Energy from waste
With Americans generating 250 million tons of garbage each year, the search for cost-effective, reliable and sustainable ways to deal with the 134 tons of material that winds up in environmentally hazardous landfills year after year is a constant one. For some communities, the solid waste solution is an EFW facility, which allows non-recyclable waste materials to be converted into useable heat, electricity or fuel through a variety of processes, including combustion, gasification, pyrolization, anaerobic digestion and landfill gas recovery.
“It’s a concept that is used widely in Europe,” said Sampson. “They don’t have room to create more landfills, so they have learned to appreciate the value of producing energy through environmentally responsible methods.”
Covanta Energy Corporation is an internationally recognized owner and operator of large-scale energy-from-waste facilities. Jill Stueck, vice president of corporate communications for Covanta, said she, too, understands community confusion over the process. But residents should rest assured that this is not the unmonitored incineration practices used before the Clean Air Act of 1970.
“It’s not even remotely close to it,” she said. “It’s a pollution-controlled, sustainable waste management program that not only embraces the three R’s of reduce, reuse and recycle, but takes it a step farther by recovering energy from waste, which is used to heat downtown areas and feed electricity back into the grid.”
“We pull out 400,000 tons of ferrous and over 150,000 tons of nonferrous metals each year. To put that in perspective, it’s enough metal to build five Golden Gate Bridges or for the production of over 1 billion aluminum beverage cans”
How does it work?
Waste is delivered to an EFW plant and temporarily stored in a bunker, which is maintained under negative pressure to control odor. The waste is then fed into a combustion chamber and burned at extremely high temperatures, generating heat, which boils water to create steam.
“People see smoke stacks and assume there is something toxic happening at our facilities, but in reality it’s just steam,” Stueck explained.
The steam turns a turbine-driven generator to produce electricity and heat while the state-of-the-art air pollution control equipment is used to cool, collect and clean combustion gases. All of the pollution controls, emissions and operating criteria comply with rigorous state and federal standards.
The residual material is then collected and filtered in order to find ferrous and non-ferrous metals that can be recycled before the remaining ash, or about 10 percent of the original solid waste material, is transported to the landfill.
“We pull out 400,000 tons of ferrous and over 150,000 tons of nonferrous metals each year. To put that in perspective, it’s enough metal to build five Golden Gate Bridges or for the production of over 1 billion aluminum beverage cans,” Stueck said.
While admittedly not inexpensive to start up, Sampson added that an EFW facility’s benefits outweigh its cost. Facilities are usually funded through municipal bonds with the payoff period laying typically between 20 and 25 years. At that point, a well-operated and maintained facility should be hitting its stride and prove an extremely worthwhile asset for the community.
Stueck said when looking at siting a new EFW facility, one factor to be considered is that the profitability of the arrangement often depends on the power purchase agreement negotiated with the utility for the sale of the electricity the plant produces. For the most part, counties want to be in control of the solid waste disposal in their communities to insulate them against radical rate changes. Given this, the preference is usually for a county to build its own facility.
“Most counties don’t want to site a landfill for waste disposal. In fact … the preference is for an EFW facility due to its much smaller footprint and relatively minimal environmental impact.”
In the 11 years that Lee County has operated its EFW facility, Sampson said thousands of people have toured the plant in order to gain a better understanding of waste management and environmental stewardship. As operations at the plant have expanded, there has been no dissent from the public regarding the ecological impact the plant has on the community.
“We have a stellar operating record and have demonstrated ourselves to be a good neighbor to the folks who live here,” Sampson noted. “Our solid waste division is committed to programs that make recycling, resource recovery and responsible waste management easier, and we will strive for even more effective and sustainable solutions for the future. We believe everything has value, even waste.”