Waste Processors Getting a Careful Overhauling

Although it can be a smelly job at times, cleanup and repair work on two, 750,000-gallon waste digesters at the South East Regional Reclamation Authority’s sewage treatment plant is progressing without raising much of a stink in the neighborhood.

The $395,000 refitting and renovation project is removing solid residues, such as sand and eggshell fragments, from the machinery, said C.J. DiPietro, operations manager. In addition, the agency plans to replace the seals that keep foul-smelling methane gas, a by-product of the process, inside the digesters. The work is to be completed by the end of next month.

Created by a sewage-eating bacteria housed in the digesters, the methane gas is used to fire the boilers, which heat the digesters and keep the bacteria at an optimum temperature. “It’s sort of a round-robin effect,” he said.

In an effort to keep odors down, the workers dumped a lime-slurry mixture into the first digester repaired, to kill the bacteria before the machinery was taken apart. So far, DiPietro said, the agency has received few complaints from nearby residents. “There was one complaint a week or two ago,” he said, after a workman fired up a pump on one of the digesters, sending a burst of methane into the air.

On Wednesday, the agency removed a heat exchanger from one of the digesters for repair. Although the smell of raw sewage abounded, the lime slurry mixture, with earlier pumping of carbon dioxide into the digester to displace the methane that was burned off kept odor at a minimum.