Dunbar Creek upgrades progressing at steady pace
Apr. 14—It's a veritable zoo at the Dunbar Creek Wastewater Treatment Plant on St. Simons Island.
Andrew Burroughs, executive director of the Brunswick-Glynn County Joint Water and Sewer Commission, made a joke about unruly plant workers before launching into a description of the various bacteria that break down chemicals like ammonia and phosphorous in the sewage collected from thousands of homes, condos, apartments and businesses on St. Simons.
The JWSC invested $5.7 million into the plant last year, with construction work starting in the middle of last year. Most of the work is maintenance and basic upgrades that have been a long time coming, he said.
It was the U.S. Navy that first built the plant, Burroughs said, in the 1940s. It got an overhaul in the 1980s after the county took over and again in 2006.
The port of entry into the plant is known as the headworks — where sewage from the rest of the island gets collected and sent to a well. There, the utility is putting some of those millions into upgrading the initial filtering equipment and installing some odor control mechanisms.
From there, sewage flows into the aeration basins, Burroughs said. That's where the bacteria live. Pipes along the bottom of the basin pump minute streams of air into the sewage, giving the bacteria air so they can do their jobs.
Currently, one basin is offline while equipment is being replaced with new models and materials, like PVC instead of metal.
Unlike the Academy Creek sewage plant in Brunswick — which uses pure oxygen in the aeration process — the Dunbar Creek plant suffices with regular air. Big pumps take in air and deliver it to the basins.
The pumps cost a lot of money in electricity to run, something the JWSC hopes to save some $40,000 to $50,000 a year on by adding automation, Burroughs said. New systems will determine when the basins have enough air and cut the pumps off. Right now, it's not unusual for the basins to get more air than they need.
After the bacteria get their fill, the wastewater is transferred to clarifiers, where solids are allowed to settle to the bottom. Liquid gets removed from the top and the solids at the bottom, called sludge, get taken away for disposal.
The water goes through a disinfection process using ultraviolet light before it gets filtered again. Both the UV treatment and filters are getting an upgrade as part of the package, Burroughs said.
Finally, more air is pumped into the water before it's released into Dunbar Creek, "because the fish need to breathe too," Burroughs said.
The project should be complete in the fall of this year, he said.
