June 4 – Decatur Utilities plans its most expensive project ever. Nearly $120 million is being spent on two sewer system improvements as part of efforts to stop sewage overflows.
One project involves renovating the wastewater treatment plant on Alabama 20 and the other involves replacing a collecting sewer line that feeds the treatment plant with a much larger pipe.
DU spokesman Joe Holmes said the sewage treatment plant renovation would include “some new odor controls. We do expect improvements with the new equipment, but because it is a wastewater plant, the odor will never be completely eliminated.”
The DU board voted in a called meeting last week to recommend approval of improvements to the Dry Creek Wastewater Treatment Plant and the Moulton Street collector sewer line.
“We believe these two projects will be generative for the wastewater system in Decatur,” said Ray Hardin, DU general manager.
Hardin said the city has “a long-standing problem with sanitary sewer overflows (SSOs), primarily caused by rain entering the sewer system.”
DU was sued by the state in 2019 over the overflows. The DU board in 2020 approved a plan to make extensive repairs and replacement of portions of the sewer system as part of the settlement of the state’s lawsuit, which was finalized in March 2021.
Construction on both projects, which is expected to be approved by the City Council Monday evening, would begin later this summer. DU could then complete compliance with the settlement agreement by March 29, 2026, Hardin said.
“Internally we don’t want any overflows, but the agreement was to minimize SSOs,” said Hardin, who added that there have been no rain-induced overflows in the two years since the project started.
As part of the settlement with the state, the utility approved a 10-year plan financed by $165 million in bond proceeds, paid for with an increase in customer interest rates.
DU has earned $3.84 million in interest on the unissued bond proceeds to date, but it will need another $15 million from the wastewater operation’s cash reserves or possibly another bond issue to complete the projects , Hardin said.
Hardin said they originally created a budget to replace 1 million linear feet of pipe over 10 years, including 250,000 feet of clay pipe and 60,000 feet of cement pipe. They also planned to replace Clark Springs Collector and Lift Station 7 in the Pines in Northwest Decatur.
However, Hardin said they had revised the budget to do the main works and the Moulton Street collectors projects. This required a reduction by half in the amount of pipe replacement financed by the bond issue, he said.
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Sewage revolts
Jimmy Evans, Gas, Water and Wastewater operations manager, said the wastewater system is in a “stressed condition” in dry and wet weather conditions.
Evans explained that a surcharge occurs when the wastewater flow in the collection pipes “doesn’t move fast enough so that it starts to back up into the system and eventually causes sanitary sewer overflows.”
For example, Hardin said there is a line running along the ditch on the west side of Central Parkway, across from the DU offices. Wastewater rises and then flows out of this line.
In addition to cracks in the old pipes, Hardin says, SSOs also occur when sewage is left in the system. The plan focuses on backups.
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Collection project
One cause of backups is when the sewer line is too small, so DU plans the $22.62 million installation of a new 60-inch sewer line on Moulton Street, replacing the 20- and 24-inch line, while the outdated gravity sewer is being replaced.
Evans said this will provide a significant increase in flow capacity for moving wastewater collected from different parts of the city to the treatment plant.
Evans said the collector will start on Moulton Street. It follows the Dry Branch Creek easement and crosses Finley Drive, to the Norfolk Southern railroad south of Davis Street Northwest.
He said they would then tunnel under the railroad. The new main will continue along Davis Street and cross the Leon Sheffield Magnet Elementary School parking lot on the east side of Decatur Fire & Rescue’s Station 2. They will tunnel under Alabama 20 and connect to the new main station at the treatment plant.
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Pumping station
The other part of the plan includes replacing the influent pump station and treatment plant main works at the Decatur Utilities Wastewater Treatment Plant, located on Alabama 20 on the Tennessee River, next to Ingalls Harbor, for $90.5 million.
Tom Cleveland, DU water-wastewater resources manager, said this part of the plant began operating in 1958.
“It’s the oldest part of the plant,” Cleveland said.
Cleveland said the current wet well does not meet submersion requirements. The new wet well will be 3.50 meters deeper, reducing the depth underground to 160 meters. The added depth, he said, should help eliminate the surcharge problem and create more capacity for future growth.
The DU board voted to award the contract for the influent pump station and main work to Garney Construction Co. of Nashville, Tennessee, for a low bid of $90.5 million. Thalle Construction Co. was the other bidder for $97.9 million.
DU has included a 5% construction contingency of $4.53 million in its plans for this project to cover any unexpected cost increases, Evans said.
The board awarded the contract for the main replacement of the Moulton Street collector to John Plott Co. of Tuscaloosa, for a low bid of $22.62 million. Six companies submitted a bid. Cleary Construction was the second lowest bid at $26.62 million.
DU has included a 10% construction reserve of $2.26 million in its plans for this project to cover any unexpected cost increases.
— bayne.hughes@decaturdaily.com or 256-340-2432
