With space left for just six years worth of garbage in the Dane County Landfill, officials are on the verge of re-engineering the 76-acre site to install a controversial system that will hasten the decomposition of waste and extend the operation of the facility by as much as 10 to 15 years.

But critics say the plan poses long-term threats to air and groundwater. And they worry that continuing to rely on the landfill has short-circuited a thorough discussion of how the region 's waste will be disposed of in the future. They say the county is missing an opportunity to move toward a future without landfills and to rely more heavily on recycling, including recycling of organic wastes such as food.

Dane County is not alone in its struggles with waste. Bill Casey, solid waste director for Columbia County and a board member of the Wisconsin Counties Solid Waste Management Association, said there are only 50 landfills, both private and municipal, operating in the state. Many of them are fast filling up, Casey said, so communities throughout the state are in the midst of discussions about where to put their garbage.

"We 're seeing this all over the state, ' ' Casey said. "It 's a problem. It 's going to continue to be a problem. Every time we close a landfill, that waste has to go someplace else. These are going to be difficult decisions. ' '

Bioreactor planned

Meanwhile, county engineers are preparing to build a $2-million bioreactor at the Dane County Landfill, just east of Interstate 39-90 on Highway 12-18.

"Bioreactor ' ' is a fancy name for a system of pumps and pipes that will circulate water and air through the landfilled garbage and cause it to decompose more quickly, thus freeing up space for more waste, said Gerald Mandli, public works director for Dane County.

The new system, which may be in operation by next fall, basically turns the landfill into "a cooking vessel, ' ' Mandli said.

Use of the bioreactor turns the current science behind the landfill 's operation on its head. Since it went into operation in 1986, the object has been to keep moisture away from the garbage. In fact, the common name for the system in use at the Dane County landfill and most landfills across the country is "dry tombing. ' '

Currently, about 20,000 gallons a day of leachate -- Mandli calls it "garbage juice ' ' -- from decomposing garbage is pumped out of the landfill and piped to the Madison Metropolitan Sewerage District plant where it is treated and discharged along with other processed wastes.

To make the bioreactor work, that leachate would be recirculated through the landfill, along with air. The air and water both hasten decomposition.

Mandli said the bioreactor was approved by the County Board last year after it became apparent that the landfill was filling up faster than anticipated.

Tons of unexpected waste jammed the landfill in 2006 and 2007, from the homes destroyed and damaged by the Stoughton-area tornado in August 2005 and from the roofing materials replaced after a hailstorm in April 2006. The landfill took in 53,000 tons of shingles in the wake of hailstorms, Mandli said.

The bioreactor is still in the design stage. Mandli said the county is taking its time with the project so that all potential problems are addressed.

More methane

Chief among those problems, according to Peter Anderson, owner of Recycleworlds Consulting in Madison and a nationally-known expert on recycling and waste disposal, is the increased production of methane, a gas produced by the decomposing garbage.

Currently, methane gas is drawn by a vacuum system from the landfill and used to power generators that turn it into electricity. That electricity, enough to power 5,000 homes, is sold to Madison Gas & Electric for $1.2 million a year.

But Anderson said collection of methane is an imprecise science. He said the federal Environmental Protection Agency estimates that systems such as those used at the Dane County Landfill capture as much as 75 percent of the methane that is generated. But he added that only that captured gas is measured, not the methane escaping into the atmosphere. A greenhouse gas, methane has more than 20 times the warming potential of carbon dioxide.

Mandli said the landfill 's gas collection system will be expanded to account for any increase in the production of methane. And he added that the county is also considering the possibility of turning the gas into a pipeline-grade gas that can be sold.

Anderson also raised concerns about site stability. One bioreactor system pumped so much water into a private landfill near Milwaukee that a small landslide ensued, though it was contained on the site.

Mandli, however, said using air in addition to the leachate should lessen the potential for such failures. He also said the county 's plans have to be approved by the state Department of Natural Resources through a rigorous six-month permitting process.

"We want to be great stewards of the environment, ' ' Mandli said. "That 's our goal here. ' '

Recycling organics

While the bioreactor approach is expected to extend the lifetime of the landfill, Anderson said relying on the landfill also forestalls discussion of more forward-looking ways to get rid of our garbage, including the recycling of organic material such as food wastes.

"There is a major fork in the road as to where we should go here, ' ' Anderson said "And we are really completely in the backwater here. ' '

Anderson and George Dreckmann, recycling coordinator for the city of Madison, have pushed for increased recycling by adding a third barrel for food waste and other organic materials that could be composted. The city 's trash does go into the Dane County Landfill.

Two-thirds of what goes into the landfill now is organic material, Anderson said.

"I think we could get very close to zero waste, ' ' Anderson added. "But maybe the next thing is for us to get the organics out. ' '

Anderson said conventional recycling takes care of about one-third of what we discard. About one-third of what is left is yard waste and the other third is organic material, such as soiled paper and food wastes.

Some Wisconsin communities already collect these wastes for composting.

Columbia County started recycling organic waste in 1991 using concrete kilns that were bought in St. Louis and shipped to the county on 30 semitrailers, Casey said. The system, known as in-vessel composting, cost $3.6 million and removes about 50 percent of the county 's organic wastes from the waste stream. The decision to go to composing came in the late 1980s, Casey said, when the county was struggling to find landfill space. The county now has no landfill and trucks its garbage to Winnebago County.

Mandli said separation of organics was discussed in Dane County two years ago when the county 's current strategic solid waste plan was authored. While a composting facility was part of that discussion, the $40-million price tag was too high, Mandli said, though recycling organics does remain a long-term goal.

No-landfill future?

Anderson, Dreckmann and others say that southern Wisconsin needs to talk about how to take care of its waste -- starting now.

Dreckmann said he 's been watching the landfill 's life span grow shorter with worry.

"I was nervous when there were only 13 years left, ' ' Dreckmann said. "It 's about a 10-year process to site a landfill. ' '

Topf Wells, chief of staff for Dane County Executive Kathleen Falk, said the county 's Solid Waste Advisory Commission is committed to finding ways of increasing the volume of recyclables. But the county 's waste management future remains tied largely to landfilling.

"Are we going to be able to move to a no-waste, no-landfill future? I don 't think that is something that has been systematically addressed by the solid waste commission, ' ' said Wells.

Mike DiMaggio, Dane County 's solid waste director, said planning the region 's waste disposal future will probably focus primarily on cooperating with nearby counties on construction of another landfill instead of contracting with a private waste disposal company such as Waste Management. Perhaps, he added, the landfill would be built in a neighboring county and Dane County 's landfill would be converted to a transfer station, from which garbage would be hauled to the new site.

"Dane County is committed to staying in the business, ' ' said DiMaggio. "Whether we transfer or build another landfill, we want to stay in the business. ' '