Zion plant turns filth into fuel

When North Shore Sanitary District leaders looked for a better way to dispose of treated sludge and waste from sanitary sewage plants, they found it in Germany.

It was a high-tech process that involved recycling and drying the waste into pellets that can be burned as fuel. The district spent about $50 million to build a Zion facility that opened in 2006 and has won numerous awards for technology and innovation.

But now, more than four years after the opening of the Zion Sludge Recycling Facility, the district faces a dilemma — they're still looking for a company willing to use those recycled sludge pellets.

“We are doing what we can to reduce it and turn it into a cleaner fuel,” said district Executive Director Brian Dorn. “But it takes a company or two to revise their Illinois air permit to burn the material. That has been something most companies have been reluctant to do.”

Sewage plants across the country are always looking for places to properly dispose of the sludge produced on a daily basis.

A sewage plant takes raw waste and filters it, separating and cleaning the liquid from the solids. The solid is disposed of, while the cleaned liquid is returned to rivers and lakes.

There once were numerous methods to dispose of the solid waste, but those are now limited because of the toxic metals in the dumped sludge, Dorn said. The common methods used included spreading the sludge over large sewage fields or onto farm fields to fertilize crops. However, Dorn said, while spreading it over fields is still allowed, lingering toxins in the sludge could enter the groundwater system, causing future problems.

In addition, he said the regulations and restrictions for spreading the sludge over farm fields vary from state to state.

Now, the most common disposal method is to mix the sludge with fly ash and dump it in landfills.

“But because of the minerals and toxic metal in the sludge, it's not the best solution,” Dorn said. “So, we went out looking for a new solution.”

That led them to Germany, where, because of a lack of land available for landfills, recycling facilities were being built that removed 97 percent of the water from the waste sludge and turn the muck into a dried pellet, Dorn said. In Germany and other locations in Europe, that pellet is recycled and used in place of coal in area factories.

The sanitary district board agreed in 2004 to build a similar recycling facility in Zion, Dorn said. Since it opened, it has reduced the amount of waste from 200 tons a day to just over 30 tons a day, said David Swarthout, who manages the recycling facility.

“Plus, the dried sludge can be burned and used as fuel for coal-firing plants,” Swarthout said. “It burns as well as a low-grade coal.”

The North Shore Sanitary District, along with consulting engineer Donohue and Associates of Milwaukee, won numerous national awards for technology and innovation after the plant opened in 2006, Dorn said.

The plant did exactly what the district wanted it to do — stopped putting harmful waste back into the ground — and resulted in a product that could be given or sold to manufacturing plants using coal furnaces, he said.

But there was a problem.

Even though the pellet has substantial value, any manufacturer that could use it would not only need to re-equip their manufacturing plants, but also reapply and adjust its Illinois Environmental Protection Agency permits to be able to burn the material.

While retooling to burn the pellets can be costly, Dorn said reopening air quality paperwork is often a new can of worms that area manufacturers aren't willing to deal with.

“Companies are not willing to go through the steps required by the IEPA for a new air quality permit,” he said. “So, right now, we continue to landfill the pellets. It's less than we were dumping before, but our goal was to stop using landfills all together.”

Maggie Carson, a spokeswoman for the IEPA, could not comment specifically about the issue, but confirmed that “Illinois generally requires air permit holders to modify their permit if they change the fuel source, such as including the pelletized sewage mentioned.”

In the interim, Dorn said, district officials will continue to meet with coal-burning plants in an effort to see if they can convince some to start burning the pellets. They're also working to try to reduce the minute amount of toxic metals still in the pellets after the drying process, which could help increase air quality.

“If we reduce the small amount of metals in the pellets, we should have an easier time trying to sell it to a company to use with or in place of coal,” he said.