Burning Question for City Officials
By Andy Piper
News You can use The Dubuque City Council will tour the Water Pollution Control Plant at 3:30 p.m. Monday and then return to the Historic Federal Building, 350 W. Sixth St., at 6 p.m. for a work session on the Water Pollution Control Plant Renovation study. The public is invited, but public input will not be allowed at this time. A public hearing will be set for a City Council meeting in the near future.
Wastewater treatment is hardly fodder for dinner table discussion, but it’s a burning issue this spring for Dubuque city officials and area environmental activists.
Dubuque is one of two Iowa cities that incinerates the sludge left over after the water from our faucets, toilets and industry flows down the drain and into the sanitary sewer system. Cedar Rapids is the other.
The water ends up at the Water Pollution Control Plant, near Julien Dubuque’s grave, where it is screened and chemically treated before being released into the Mississippi River. The leftover residue is burned, and the ash is taken to the landfill.
The plant is overdue for renovation, and the city is setting aside about $45 million over the next five years for that purpose. At issue is whether the city should rehabilitate the existing incinerators and continue business as usual, or construct an anaerobic digestion plant that would eliminate burning.
The leftover sludge would be prepared for agricultural use as a soil conditioner, compost or both. An added benefit to anaerobic digestion is the methane gas produced in the process can be captured and used for fuel to operate the plant. The Davenport, Iowa, plant produces enough gas that it receives money back from the power company, according to Jonathan Brown, manager of Dubuque’s wastewater pollution-control plant.
“We’re looking at basically the same plant we had 45 years ago,” Brown said. “The question is not whether we’re going to do something, but what are we going to do. Everyone needs to keep in mind that every community is different and has its own needs. There is no cookie-cutter solution. Both options have merit if applied properly.”
Some of the factors the City Council will weigh are initial costs, annual operating costs, future capital costs, long-term viability of the system, and – with Mayor Roy Buol’s and the council’s emphasis on “green initiatives” – the system’s carbon footprint.
To Michael Breitbach, of Mississippi River Revival, an environmental group, the decision is a no-brainer.
“People are approaching this as a financial matter,” Breitbach said. “They’re showing that anaerobic digestion is very close to incineration in terms of the money. Even if it wasn’t, I’d still fight for it.”
“River Revival’s first line of argument is there are some things you just shouldn’t do,” Breitbach said.
The group has passed out pamphlets showing some of the byproducts of incineration. The list includes mercury, nitrogen dioxide, particulate matter (a mixture of solid particles and liquid droplets), PCBs and sodium dioxide. That the emissions are highly regulated isn’t good enough for Breitbach.
“Incineration makes it possible for people to think that these things just go away,”
Breitbach said. “There are things created in the burning situation that don’t even have names yet. They are referred to as PICs – particles of incomplete combustion – basically, that other stuff. There’s no sense putting this into the environment when you can avoid it.”
Brown said Dubuque’s sludge is quite clean in comparison to most other cities, but there are emissions concerns as far as mercury output.
“It’s hard to know how much mercury comes out, but some does come out,” said Paul Schultz, solid-waste management supervisor. “When you burn, you are putting carbon dioxide into the air, and I think we’re likely to see some tightening of air-emissions regulations, and that could add costs to incineration.”
Initially, renovating the existing plant will be less expensive, but it would appear that those savings will be lost over time.
“With the incineration option, we would have to come back in 15 to 18 years and look at doing something again,” Brown said. “With digestion, we’d probably be looking at 40 years, with general maintenance costs along the way.”
Powering the plant is another factor in digestion’s favor. Incineration requires about 1.6 million kilowatt hours of electricity each year and 18,000 gallons of fuel oil. Anaerobic digestion would consume about 700,000 kilowatt hours and less than 1,500 gallons of oil, according to research presented by Strand & Associates for the city of Dubuque.
One undetermined cost of anaerobic digestion is having to transport the agricultural product.
“The challenge is our topo-graphy,” Brown said. “We would have to travel quite a way out of town to find suitable land. It has to be pretty flat.”
As for the carbon footprint, Schultz and Brown said that is something the City Council will have to decide. Schultz said that in general, anaerobic digestion is considered to have less environmental impact.
In 2005, one year before Buol took office, the U.S. Conference of Mayors met in Chicago. One stipulation in the climate-protection agreement signed by the attendees is to “recover wastewater- treatment methane for energy production.”
“I’m open to all the green, sustainable options that are out there,” Buol said. “If it’s going to be a facility where methane is produced, we’ll take a look at it. It’s going to be expensive no matter how we proceed.”
Mississippi River Revival acknowledges that there is only so much city government can do and that ultimately individuals have to accept responsibility for the environment. But the group sees this decision as a great opportunity for the city to put its money where its mouth is.
“Think globally and act locally,” Breitbach said. “If you want to be sustainable, you have to do the real thing. You can’t just do it in name.”
Originally published by Andy Piper TH staff writer/ apiper@wcinetcom.
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