DeKalb County. (Engineering Notes).
Georgia, Florida, and Tennessee are embroiled in what the newspapers are referring to as "water wars, battling each other over the Southeast's limited--and dwindling--water supplies. The wars themselves are a relatively recent phenomenon. The problem, however, has been long in coming.
DeKalb County recognized the potential for the water wars long ago, and, in the early 1990s, began making plans to limit their effect on the county's 600,000-plus residents. The county, the second largest in the Atlanta metropolitan area, is working to overhaul an antiquated water plant, replacing it with a state-of-the-art ozonation facility that will be able to handle increasingly stringent regulations and anticipated population growth.
The Scott Candler Water Filter Plant was built in 1942. Population growth and the rise of more advanced treatment techniques have limited its effectiveness in serving the county. The new water treatment facilities will combine a 150-mgd plant (the existing plant can only treat 128 mgd) with three raw water reservoirs with a capacity of almost one billion gallons.
"As long as 10 years ago, it was obvious to many that off-stream storage was going to be a critical issue because of concern about the limited water supply," DeKalb Water and Sewer Department Deputy Director Margo Howse says.
The reservoir project is under way; the first reservoir went online in May 2002. Once it is completely filled, two existing reservoirs will be rained and renovated.
The county recently received its notice to proceed on the treatment plant. The new plant will feature solids removal facilities (the old plant had none, meaning that every so often, the county would have to drain the basins and hose out the settled mud), updated filters, and ozonation technology, which will replace the chlorine system that is currently used.
Initially, the county wanted to retrofit the existing plant, but its filters were too shallow to accommodate advanced treatment technologies. When it became obvious that a new plant was necessary, the county bit the bullet and planned construction of a plant that would not only provide for increased quantity, but also would improve water quality. (The county is assuming that future raw water supplies may be somewhat degraded.) Additionally, ozonation is effective against a number of microorganisms--such as Cryptosporidium, Giardia, and e-coli bacteria--that chlorine does not always kill.
Plans for the reservoirs hit a roadblock almost immediately, when the site chosen for the new reservoir was found to be an old illegal dump site that the county traced through aerial photography to the 1960s. The design was put on hold until the site was remediated by Atlanta-based Westinghouse Remediation Services, adding two years and $7 million to the project.
A second problem occurred when residents in the neighborhoods surrounding the plant complained about perceived aesthetic problems. Over nine months the county met with neighborhood representatives, ultimately deciding on a redesign and landscaping plan by Atlanta-based Ray Ashley and Associates that incorporated utility pole relocation, construction of an underground drainage system, redesign of a retaining wall, as well as installation of sidewalks, benches, and lights for a linear park along the neighborhood.
The final cost of construction for the reservoir phase of the project is expected to be $44 million. Golder Associates (Atlanta, Georgia) is designing the project, and Western Summit (Denver, Colorado) is the contractor. The treatment plant, designed by Camp Dresser & McKee (Cambridge, Massachusetts) and built by Archer Western Contractors (Arlington, Texas), will cost $153 million. The project is being funded through the sale of water and sewer bonds.
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||new water plant in DeKalb County, Georgia|
|Date:||Oct 1, 2002|
|Previous Article:||Virginia Department of Transportation. (Engineering Notes).|
|Next Article:||Dryden Bypass project. (Engineering Notes).|