WATER RECLAMATION
Once water leaves a consumer's home or a local business after consumption, it enters the Authority's complex system of pipes and lift stations known as the conveyance system. The final destination of this system is one of three water reclamation facilities (WRFs) - Northeast, Shoal Creek or W.B. Casey.
The W.B. Casey facility houses the Authority's water reclamation departmental offices and wastewater laboratory. This state-of-the-art upgraded wastewater treatment facility was put into operation in the summer of 2004.
In these water reclamation facilities, wastewater passes through a series of standard treatment and purification processes. The first process is called preliminary treatment, which consists of screening and grit removal. Debris, sand, and grit collected in these processes are hauled to a landfill for disposal.
The next stop in the treatment train is called the Biological Reactor basins. This is the heart of the process and involves the presence of billions of common bacteria and microorganisms whose primary function is to stabilize the waste materials in the water by utilizing the remaining organic matter and nutrients as their food supply.
Once the water has been biologically treated, it is sent to settling tanks, called clarifiers, where solids are separated from the water for further recycling. Effluent water from these clarifiers is then put through a disinfection process to kill any remaining pathogens. CCWA uses both chlorine and ultraviolet disinfection processes. At this point, most water utilities would discharge their effluent to a receiving stream, which is what happens to effluent at our Northeast WRF. But CCWA uses an additional polishing treatment process called Natural Treatment Systems.
Natural Treatment Systems
After the initial phase of wastewater treatment, the CCWA then utilizes natural treatment systems to complete the purification of this reclaimed water. This tertiary stage involves both spray irrigation of treated wastewater on a land application system (LAS), and the discharge of treated wastewater into a network of constructed wetlands.
LAS by spray irrigation of treated wastewater is a relatively common practice today, but 28 years ago, the CCWA was one of the first systems in the world to incorporate this wastewater reclamation practice. The treated effluent from the WRF is pumped to a holding pond and then eventually sprayed into a complex rainforest environment. Trees and soils on the 4,000 acre site form a "living filter" that purifies the water before it passes naturally into the groundwater supply and eventually into an Authority reservoir.
Today, the Authority continues to build upon its reputation for advancing water and wastewater treatment innovations. Currently, the CCWA is one of the few metropolitan water utilities in the country to utilize constructed wetlands as a final treatment stage of water reclamation. These wetland systems provide filtration, plant uptake and an environment for microbial treatment of the water that flows through them. In September 2003, the Shoal Creek Land Application System (LAS) was taken out of service as the new 4.4 MGD Panhandle Constructed Wetlands System was brought on line.
In September 2005, phase one of the Huie Constructed Wetlands was brought on line providing 3.5 MGD of treatment capacity. The 2.6 MGD phase two of this system was brought on line in August 2006 and the 3.1 MGD phase three was brought on line one year later.
Constructed wetlands treatment capacity on the Huie site currently stands at 9.3 MGD. The 8.2 MGD phase four of the system is currently under construction and is scheduled to become operational by summer of 2010. The photo to the right shows an aerial view of the CCWA's Huie Constructed Wetlands site.
Constructed wetlands offer a cost effective, energy efficient alternative with lower operational and maintenance costs. The wetlands also provide a much more sustainable water system that enhances the potable water supply availability to our customers. The constructed wetlands allow the CCWA to increase its wastewater treatment capacity, while dropping the costs incurred in the process. The cost to build wastewater facilities using constructed wetlands is $4.73 a gallon, compared to nearly $10 a gallon using the more conventional methods.
The CCWA garners national and international interest in our constructed wetlands. Industry peers come from all over the United States, and as far away as Australia, to learn more about our innovative use of constructed wetlands.
The Authority's LAS fields and constructed wetlands are included among the over 4,000 acres of protected green space that will never fall prey to residential or commercial development. This acreage provides for hearty forests and wildlife, not to mention incredible recreational opportunities located in such a close proximity to a major metropolitan city.
The photo to the left shows Egrets enjoying the haven they have found at the Clayton County Water Authority’s Panhandle Road Constructed Wetlands.