On Tuesday, May 28th, the Decatur Utilities Board of Directors approved almost $120M to fund two major improvements to the Dry Creek Wastewater Treatment Plant (WWTP) and the sanitary sewer collection system. $95M will be allocated to replace the Influent Pump Station and Headworks (IPS/Headworks) at the WWTP and $25M will fund installation of a new Moulton Street Collector sewer main. Garney Construction Co. of Nashville, Tennessee was low bidder for the IPS/Headworks project and John Plott Company of Tuscaloosa, Alabama was low-bidder for the Moulton Street Collector project. Pending final approval by the Decatur City Council, construction for both projects should begin later this summer.
Both projects are major components of DU's ongoing Sewer Rehabilitation Plan to mitigate and minimize sanitary sewer overflows (SSOs) as required by a settlement agreement with the Alabama Department of Environmental Management reached in 2021. Since that time, DU has replaced 325,000 linear feet (LF) of sewer mains and 5,000 sewer services. Work has also begun on rehabilitating the Clark Springs Collector main in Southwest Decatur. DU's aggressive rehab efforts over the last three years have begun to yield promising results, as the last rain-induced SSO occurred in March of 2022 - more than two years ago.
IPS/Headworks Project:
The existing IPS/Headworks equipment at the WWTP has been in continuous operation for almost 33 years and is nearing the end of its expected useful life. The age of the current IPS/Headworks and its design can restrict flow of wastewater through the WWTP, causing it to back up into Sewer Basin 1 collector mains. This condition - known as "surcharge" - can eventually back up through manholes and result in rain-induced SSOs. For reference, DU has 17 sewer basin throughout its wastewater system service areas. All other sewer basins feed Sewer Basin 1 which in turn transports the collected wastewater to the WWTP.
The design of the new IPS/Headworks will eliminate the surcharge condition in Sewer Basin 1, improve WWPT operational capabilities and provide additional flow capacity within the sanitary sewer collection system to meet current and future demand.
The project is expected to begin later this summer take three years to complete.
Moulton Street Collector:
The Moulton Street Collector will consist of 7,400 LF of new 60-inch ductile iron sewer main that will run from Moulton St. through Sewer Basin 1 to the WWTP. The new 60" collector line will allow for greater capacity to transport wastewater collected from other sewer basins in the city to the WWTP. Work is expected to begin later this summer and take approximately two years to complete.
How Will This Expenditure Be Funded?
The majority of the almost $120M approved by the DU Board for the IPS/Headworks and Moulton St. Collector projects will be paid for out of bond funds borrowed in 2021 to fund the Sewer Rehabilitation Project. The original bond amount borrowed was $165M with almost $4M in interested earned to-date. Of that total, approximately $71M has been spent on sewer main rehabilitation projects that have been completed or are currently under contract. In addition, funds are committed for the Clark Springs Collector project, a new lift station, a voltage upgrade project at the WWTP and engineering services related to the IPS/Headworks and Moulton St. Collector projects.
The $120M cost of the projects will be paid for from remaining bond funds and the wastewater system's cash reserves. Because of the reallocation of remaining bond funds to these projects, the total linear footage of rehabilitated sewer mains will be reduced from a total of 500,000 to 400,000 linear feet for FY2021-FY2025. However, DU will continue to fund ongoing sewer main rehabilitation projects from its annual operations budget in following years.
"This will be a generational project for Decatur Utilities that will impact current and future customers for many years to come," said Ray Hardin, Decatur Utilities General Manager. "These two projects - combined with the rest of the sewer rehabilitation plan - will continue to reduce rain-induced SSOs and position us to meet future residential, commercial and industrial growth over the next several decades."
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