Charles City has lime sludge to sell

City officials ponder policy for getting rid of water treatment byproduct

By Chris Baldus

cbaldus@charlescitypress.com

Charles City has a pond full of lime that could be worth something.

At least, that’s what city leaders are hoping, so rather than paying tens of thousands of dollars to have the lime removed and hauled away, the city could possibly break even or better.

However, for a city of this size that doesn’t expect to have a regular supply of lime to market on even an annual basis, there is no template plan.

So that is what city officials are working on, City Administrator Steve Diers said. The plan is to sell the lime or to get an arrangement with an interested party to have the lime removed from the pond and hauled away at no expense to the city.

The lime is a byproduct of softening the city’s water supply. More than 10 to 15 years ago, before the city built two lime lagoons, the city had an agreement to regularly spread the lime over agricultural land. With the lagoons, the supply of lime settles and waits.

After about 15 years, one of the lagoons is almost full and the city is letting it dry out in anticipation of removing the lime.

“The idea is it stills has some benefit for ag land application,” Diers said.

The city had a party interested in taking the lime, but then more entities expressed interest in obtaining the lime. Diers said that leads to policy questions: Do we sell to one entity? How do we determine value? Will the city have a regular supply of lime to sell?

“The question is what is what that regular practice (should be),” he said. “We have gone 15 years have not done anything.”

The supply of lime available will likely fluctuate with water usage in the city. The addition of another manufacturer with high-water use could lead to more lime available, for example.

The city’s need is to get the lagoon emptied and keep it useable.

“I don’t think we want to get to a place where we are now where one pond full,” Diers said.

The city is just no longer using the one lagoon for the last year, which is allowing the lime to dry out.

Diers said the city needs to do more testing of the lime to determine the water content of the lime and its value before it moves forward, perhaps, with a bid process.

“We have not really seen this model in other community,” he said.

According to an Iowa State University report, eight Iowa cities representing, according to the U.S. Census Bureau, 23 percent of the state’s population of 3 million, collectively produce an estimated 64,470 tons of lime sludge per year, and currently have 371,800 tons (dry weight basis) stockpiled.

Other cities have run into problems with handling their lime sludge. Last summer, the Iowa Department of Natural Resources ordered the city of New Hampton to discontinue land application of its lime sludge at its current contractor’s properties. Unsatisfied with receiving only one solution proposal, the city put the issue on hold until this year when it will solicit more proposals for its Sludge Facilities Improvement Project.