Dalton: Sludge to compost

DALTON, Ga. — Solids pulled from industrial and human wastewater treated by Dalton Utilities are being converted to fertilizer and used to grow grass, tomatoes, vegetables and more.

Officials involved in the effort say folks shouldn’t be squeamish.

“People sometimes get a phobia about this process,” said Gerry Harstine, owner of Harvest Farms, the firm that is distributor for the compost produced at Dalton Utilities.

“But if you think about it, whether it’s dog manure or a bird or squirrel that dies, all that decays and becomes dirt,” he said. “That’s all that dirt is: Something that was alive and died and decayed. We’ve taken it through the process to accomplish something new.”

Mr. Harstine said the wastewater sludge undergoes such an intense heating and treatment process that it’s safer than most bagged soils at retail stores or the normal soil in people’s yards.

He said tests on the product found higher nutrient levels than other retail soils and a much better smell than manure.

The partnership between Harvest Farms and Dalton Utilities started six years ago.

Dalton Utilities official Lynn Rush said the sewer sludge comes from the utilities’ three wastewater plants and is taken to the sludge-handling facility near Dalton’s South Bypass. There it is dried with a centrifuge, treated and heated before it becomes compost that exceeds federal and state standards for safety, he said.

Mr. Rush said in addition to reusing a natural product, the effort also saves Dalton Utilities money by keeping the bio-solids out of the landfill, where he said it costs the company at least $25 per ton to dump.

And they noted the resulting environmental benefit of extending the landfill life by not filling it up with sludge.

Mr. Rush said the process typically produces about 100 tons of compost per day, though a recent mechanical change at the plant and the recession have cut production in half.

He said local carpet mills and chemical plants have been at a fraction of normal production during the current economic crunch, resulting in less wastewater. And less wastewater means less compost.