The project, aided by a bill proposed by Sen. Kevin Engler, R-Farmington, would allow city residents to dump their yard waste into a bioreactor landfill. The yard waste, including grass clippings, tree limbs and leaves, would mix with the landfill's household trash, thus decomposing faster and speeding up the production of methane gas, said Jim Hull, director of the solid waste management program for the Missouri Natural Resources Department.
Although bioreactor landfills act much like common landfills, the city would increase decomposition through circulating leachate -- the liquid found in trash --and adding oxygen or water.
The city would then capture the gas and turn it into electricity.
"Will it be enough to fuel the whole city, no," Engler said. "Will it take some of the load off, yes."
Engler presented his bill to the House Energy and Environment Committee on Tuesday. Under the bill, residents in areas that house bioreactor landfills would be allowed to combine their yard waste with their everyday trash. Currently, residents must separate yard waste from ordinary waste.
Engler praised the potential bioreactor landfill project for disposing of yard waste, producing energy and --since the waste decomposes faster -- creating additional space in landfills.
He said it could also save money for some 300 Missouri communities that have separate yard waste management services.
"And that's why it's a win-win," Engler said.
Eric Lombardi, executive director of Eco-Cycle, a non-profit zero-waste company based in Boulder, Colo., said the process was more complicated and hardly beneficial.
"The problem is that, according to a couple sources, including the IPCC (Intergovernmental Panel on Climate Change), the lifetime capture rate when you bury biodegradable material is only 20 percent," Lombardi said, "which means 80 percent is released into the environment."
Lombardi said releasing 80 percent of the landfill's methane gas, which is among the top 10 greenhouse gases, could increase global warming.
He said it could take dozens of years for yard waste to decompose and all the methane gas to escape. But often the gas-capturing equipment is only in use for a portion of that time, Lombardi said.
Lombardi said Germany banned burying biodegradable material and instead places it in what are essentially large compost piles.
It then generates energy from the compost without the mass methane release and later delivers the compost to farmers.
"It's a beneficial cycle," Lombardi said. "It's a beneficial use compared to burying all this good stuff."
A U.S. Environmental Protection Agency report cites another possible disadvantage of bioreactor landfills. According to the EPA, such landfills could release more odor.
Hull said that's possible, since the yard waste helps hasten the degradation process.
"It would stand to reason that they might produce more odors," Hull said.
Despite such concerns, House committee members raised few doubts about the project.
Rep. Ed Robb, R-Columbia, who is sponsoring a similar vision of the bill in the House, said the project would help the city reach its renewable energy goals. A Columbia ordinance states that by the end of the year 2 percent of its power must come from renewable energy sources.
"Columbia is a very green-leaning community," Robb said.
He said Columbia is willing to pay $3.5 million for the bioreactor project. A bioreactor landfill cell, which is essentially a new portion of the landfill, would save the city some $800,000 a year, since it could consolidate its trash pick-up routes.
The bioreactor landfill in Columbia would be the state's first. But it wouldn't be the first landfill in the state to capture methane gas and convert it to electricity.
Hull said Springfield already converts the methane emitting from its landfill into electricity. But he said other Missouri communities could emulate Columbia's landfill project.
"I think people are probably going to watch how Columbia fairs in this," Hull said.