After the initial phase of wastewater treatment, CCWA utilizes natural treatment systems to complete the purification of this reclaimed water. This tertiary stage involves the discharge of treated wastewater into a network of constructed treatment wetlands and some spray irrigation on a land application system (LAS). CCWA is one of the few metropolitan water utilities in the country utilizing constructed treatment wetlands as a final treatment stage of water reclamation.
By using constructed treatment wetlands to recharge our water supply, CCWA has developed a truly sustainable water supply. During Georgia’s second worst drought on record in 2007, Clayton County’s raw water reserves remained at 77% of capacity. This innovative approach garners industry attention throughout the U.S., and the world, as peers look to Clayton County to learn more about our sustainability practices.
Clayton County is divided by the subcontinental divide and lies in the upper part of the Flint River Basin (which flows to the Gulf of Mexico) and the Ocmulgee River Basin (which flows to the Atlantic Ocean). The limited water resources available in the county have driven CCWA Management and Board of Directors to think outside the box and implement innovative approaches to water management as far back as the late 1950’s.
In the 1970s, CCWA selected a spray irrigation Land Application System (LAS) as the preferred wastewater treatment method and constructed what at the time was the largest municipal spray irrigation system for treated wastewater in the United States. CCWA operated the LAS for almost 30 years.
During the development of CCWA’s 2000 Master Plan, constructed treatment wetlands were identified as the most reliable, sustainable option for both treatment and water supply augmentation. Constructed treatment wetlands have proven to require much less land, energy, and maintenance than the irrigation systems while continuing CCWA’s tradition of using natural systems for water reclamation.
Constructed wetlands treatment is a natural process involving plants, soils and the bacteria naturally occurring within the aquatic ecosystem all playing a part in removing residual nutrients. These wetland systems provide filtration, plant uptake and an environment for microbial treatment of the water that flows through them.
The level of treatment achieved through this process provides a finished product that is in accordance with all Environmental Protection Agency and Georgia regulations.
In response to the need for increased wastewater treatment capacity, CCWA partnered with CH2M HILL to develop an Indirect Potable Reuse system consisting of advanced wastewater treatment followed by constructed wetlands treament before dischargnig into the water supply reservoirs.
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 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.
In September 2003, CCWA put its first constructed treatment wetlands into operation when the Shoal Creek Land Application System (LAS) was taken out of service and converted to the Panhandle Constructed Wetlands System with a capacity of 4.4 Million Gallons Per Day (MGD).
With the success of the Panhandle Road site, CCWA began looking at the much larger E.L. Huie Site for its next conversion. From 2005 until 2010, the E.L. Huie Site was converted from the aging Land Application System (LAS) into a 532 acre constructed treatment wetlands site. The project was completed in four phases and was funded through a combination of municipal bonds, a GEFA loan and designated funds from CCWA.
The site has 263 wetted acres and is currently designed to indirectly recycle up to 17.4 million gallons per day (MGD), which is almost all of the current daily flow from the W.B. Casey Water Reclamation Facility.
In September 2005, phase one of the Huie Constructed Wetlands was brought on line providing 3.6 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.
The transition from irrigation to wetlands has also resulted in significant energy savings due to the reduced need for pumping and maintenance. CCWA has reduced maintenance staff along with reductions in equipment and materials. Rather than maintaining miles of irrigation pipes and numerous valves and pumps, routine maintenance consists primarily of vegetation management. The operation used to require 100 to 150 acres of land for 1 MGD of treatment by irrigation, but now only needs 20 to 25 acres for wetlands treatment. The 8.1 MGD phase four of the system was brought on line in September 2010, bringing the site's total treatment capacity to 17.4 MGD. With CCWA customers using an average of 25 MGD, we are able to return almost as much water as consumers use each day.
Another benefit of the constructed treatment wetlands is the enhancement of green space.
This aquatic eco-system offers sanctuary for a wide array of life forms. Wildlife abounds in these areas providing nesting areas for untold numbers of songbirds. Coastal and wading birds such as the Great Egret, Ibis and Rails can be seen on occasion wading the shallow marsh zones. Plus, waterfowl such as Canada Geese, Mallards and Gadwall frequently stop over during their migration in the winter.
The photo shows Egrets enjoying the haven they have found at the Clayton County Water Authority’s Panhandle Road Constructed Wetlands.
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, India and China to learn more about our innovative use of constructed wetlands.
The success of these constructed treatment wetlands has led to accolades and several industry awards, including:
The National Assocation of Counties published an article about the Authority's constructed treatment wetlands.