Daily photo by Jonathan Palmer|
Effluent discharge from wastewater treatment plants in Hartselle and Falkville ends up in the waters of Flint Creek.
Flushing Flint Creek
Sewer water impacts Morgan
stream's flow during drought
By Ronnie Thomas
firstname.lastname@example.org · 340-2438
HARTSELLE — A nonstop magic show occurs here on Garner Road.
There are no sleight-of-hand card tricks or rabbits jumping out of a hat in this 24-hour, seven-day-per-week performance.
If you catch the first act at Hartselle Utilities wastewater treatment plant, you'll be amazed at the crystal-clear sewage water that cascades over a weir at the end.
During a drought, however, it can make up a significant amount of the water you see in Flint Creek.
The creek also occasionally gets a liquid boost from a water treatment procedure at Falkville.
"Look around," said Brad Bole with the Flint Creek Watershed. "Most of the creeks are dry. Hartselle and Falkville do increase the water flow during a drought, but they increase the flow no matter what time of year it is."
Does it impact water quality?
"As for dissolved oxygen in the stream, it's good," Bole said. "It's actually going to help this time of year. But the utilities don't have a process that removes nutrients such as nitrates and phosphates before discharging."
Nutrients increase algae growth, Bole said, and when the bacteria breaks down and the algae dies, it will take oxygen from the water.
"In this perspective, this isn't good, but it isn't something wrong that the utilities are doing," he said. "Regulatory agencies at this time don't have a problem with nutrients going into the streams. This is an issue we've worked on for 15 years in trying to reduce them."
From 16 pumping stations across the city, the sewage comes to the 2.7 million gallon treatment plant. As it flows through oxidation ditches in an activated sludge process, brush rotors continually stir the murky waste in mixed fluid, adding oxygen.
The show doesn't end with the dropping of colorful drapes. What rolls down the weir and splashes off rocks in Shoal Creek forms a crystal clear, see-through curtain. The water appears ideal for a shower. A thirsty man might not think twice about drinking it, unless he knew its source.
Robert Wright, sewer and wastewater superintendent at HU, said the treated water meets Flint Creek about 400 yards south of the facility. It eventually flows into the Tennessee River in Decatur between the Interstate 65 bridge and Hudson Memorial Bridge.
"We're probably the major contributor to the flow of Shoal Creek during a drought, and we're definitely contributing to the flow of Flint Creek," Wright said.
He said during a heavy rain, the plant, built in 1986, can handle a peak flow of 5.4 million gallons a day, keeping 2.7 million gallons coming into the plant.
"We can divert the excess water to our 10-acre surge pond, store it, wait for the initial flow to return to normal, and pull it back through the plant before discharge," he said. "During the past few years, HU spent more than $5 million on rehab work, including installation of an inflow and infiltration diversion box at the headworks to give a constant flow."
Wright said on average the influent has anywhere from .5 to 4 parts per million of dissolved oxygen and what HU puts into the creek has from 7 to 8 ppm.
In contrast to HU's operation, Falkville's process involves a 13-acre lagoon system, consisting of three settling ponds off Robinson Creek Road.
Jimmie Walker, the town's mayor and wastewater superintendent, said a pumping station behind Falkville High School sends the town's sewage to the lagoon at an annual average of about 200,000 gallons a day. Gravity flow takes it the rest of the journey.
"The first pond is for primary treatment, the next for secondary treatment and the third is a polishing pond, which settles out more of the solids for bacteria to consume," he said. "From there, we release directly into Flint Creek."
But the release isn't consistent. Falkville discharged during December and January, and hasn't released since February. There's a good reason.
"We like to discharge during the winter rainy season," Walker said, "when our permit for release limits on fecal chloroform is 2,000 parts per million and also because the creek is flowing at its highest level. During the summer, our limit is 200 parts per million."
Walker said during dry and windy weather, evaporation drastically drops the ponds' water level. And he said the permit dictates the level of the creek at the point the town can discharge.
"If the creek gets below a certain level, we can't release," he said. "The average annual amount that Falkville dumps into Flint Creek is about 38 million gallons."
Walker also is pleased with the effort his utility makes in releasing the cleanest water possible.
"The creek has an average of 11.725 times more fecal chloroform than we're discharging," he said. "I suppose that can be attributed to pasture runoff and wildlife in the creek."
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