The Atlanta Journal-Constitution
Michael Pearson, Staff
December 11, 2000
It wasn't very long ago that swampy, soggy, buggy wetlands were something to be filled in, built over and forgotten.
Now their natural pollution-fighting power is being recruited to deal with one of metro Atlanta's most pervasive growth-related problems: wastewater.
Clayton County plans to spend several million dollars over the next decade to build new wetlands designed to help treat up to 28 million gallons of wastewater each day. The system will be the first in metro Atlanta and one of 19 in the state, according to the Georgia Environmental Protection Division.
Finding new ways of dealing with Atlanta's increasing wastewater volume is a priority. Regional development could be curtailed unless communities can find ways to avoid overburdening streams with waste, according to the EPD.
Using wetlands is an option advocates say is loaded with benefits, at least for communities with abundant cheap land. In the long run, wetland treatment is less expensive than traditional chemical treatment, it's easier and it creates abundant wildlife habitat, said Mike Thomas, a program manager for the Clayton County Water and Sewer Authority.
"You just turn it on and let it go, and Mother Nature takes care of it," Thomas said.
The wetlands are built to resemble slightly terraced rice paddies, with interconnected watery enclosures separated by earthen berms and filled with plants such as cattails and bulrushes. Treated wastewater from nearby plants is piped into the wetlands and moves slowly through the marshy environment.
In a process mimicking that present in natural wetlands, plants and microbes in the water absorb some of the pollution, and much of what's left either sinks to the bottom or evaporates during the water's two- to three-day journey.
What emerges should be cleaner than the waterway it is discharged into, Thomas said.
The U.S. Environmental Protection Agency says wetlands are an "effective and reliable" way of treating wastewater but cautions that they may not remove enough of one key pollutant —- nitrogen —- to meet wastewater discharge limits. A nutrient, nitrogen can suck oxygen from water, endangering aquatic life.
Clayton County officials say they will deal with that by boosting pre-treatment to remove even more pollutants before pumping wastewater to the two wetlands it plans to build.
Bob Scott, manager of the engineering and technical support program for EPD's water protection branch, said Georgia's experience with wetlands has been generally positive.
But Bruce Thomson, a professor of civil engineering at the University of New Mexico, is not entirely convinced. Thomson has been critical of the claims of some wetlands backers who say the system is nearly foolproof.
"They have really oversold the technology as far as I'm concerned," he said.
But he said that under carefully monitored conditions, wetlands can be an appropriate finishing step for highly treated municipal wastewater.
Once completed, Clayton's two wetlands will transform at least 660 acres of field and forest into a virtual paradise for animals and insects. The county also plans to allow widespread recreation in the second wetland, planned north of Lovejoy. Clayton County will create the wetlands from land it already uses to dispose of treated wastewater through a system of sprinklers.
Dan Hitchcock, a University of Georgia doctoral student who is studying a waste treatment wetland in Tignall, said the advantages of such systems —- particularly for smaller communities —- are wide-ranging.
Wetlands are less labor-intensive, require less maintenance and are less expensive to build than state-of-the-art chemical treatment plants.
Clayton County expects to spend far less on its wetlands and associated upgrades than it would to build a new treatment plant.
But Hitchcock said the biggest advantage of using wetlands to treat wastewater is aesthetic.
"It's a nice place to work," he said. "I never thought I'd say that about a wastewater treatment plant."
The Clayton County projects are still under review by the EPD. Construction is expected to begin on the first wetland next spring, and they will be phased into use over the next 10 years.
Copyright 2000 The Atlanta Journal-Constitution
