High-tech sludge dryer coming to City of Lenoir wastewater treatment plant

LENOIR, NC (July 9, 2020) — One of the foundations of modern civilization is indoor plumbing. Running water and flushing toilets make life better. In a city, everything flushed down a toilet doesn’t magically disappear. It all gets treated at a sewer plant.

This week, workers started installing a new treatment system at the Lower Creek Wastewater Treatment Plant. Staff have nicknamed the new equipment “the poop dryer.” The new system will replace the plant’s old treatment process, “the poop mixer.”

Gryphon Drying System being installed at the Lower Creek Wastewater Treatment Plant.

When a toilet is flushed in the City of Lenoir, that sewer water travels to a City wastewater treatment plant. Screens at the plant filter out all the solids in the sewer water. That water is treated and released back into local creeks that run into the Catawba River. The stuff left over is called “sludge” or “cake.”

The old machine at the Lower Creek Plant would heat and mix sludge with lime. The process kills bacteria, and creates a Class A fertilizer that farmers used on fields.

One of the downsides of the old system was that mixing in lime created a large volume of fertilizer. Also, the lime was dusty and corrosive. The mixer was 20 years old. Primary parts were breaking and it was becoming more difficult and expensive to fix. Machines don’t last forever.

“We were having continuing maintenance issues, and it was time to do something,” Public Utilities Director Radford Thomas said.

Last year, Thomas started researching new treatment systems. After several site visits, Thomas suggested to Council that the City buy the Grpyhon Drying System.

The Gryphon uses a belt and propane heaters to dry and pasteurize sludge. Staff dump sludge or cake in at one end. The cake moves via a belt under several propane dryers. At the end of the belt, the dried sludge has become a Class A fertilizer (without lime). The fertilizer goes into a truck to be stored or taken to a field. It takes about 30 minutes from the start to finish.

“This will be a much cleaner process and will create a much smaller volume,” Thomas said. “It will also be more efficient and easier to maintain. This is a state-of-the-art system.”

In February, Contractors started prepping the existing building for the new dryer. The first section of the dryer arrived Tuesday, July 7. All dryer parts should be on site this week.

“It’ll take a couple months to get it up and running and tested, but we hope to have it online in October,” Thomas said. “Barring any unforeseen problems.”