The combination of years long drought and explosive growth in the Atlanta metro area has both taxed the local water system and fueled the 20-year plus Tri-State Water War among Georgia, Alabama, and Florida. Emory University’s newly launched Water Hub offers a real-life working solution to the region’s current and future water scarcity challenges.
Lake Lanier’s low water levels result from drought and growing water demand from the Atlanta area. Source: Mike Gonzalez
Since 1990, government officials representing Georgia, Alabama, and Florida have waged a legal battle about the use of water in the Alabama-Coosa-Tallapoosa and the Apalachicola-Chattahoochee-Flint River basins that hug the borders of the three states. Atlanta’s rapid urban growth during the past three decades has exponentially increased the demand for fresh water sourced from the two water basins, which decreases the downstream water flow to power generation plants, fisheries, and shellfish beds located in Alabama and the Florida panhandle.
The water basins at stake in the Tri-State Water Wars. Source: Southern Environmental Law Center
The Tri-State Water Wars intensified during the 2007 to 2009 drought. In addition, property owners along the shores of Lake Lanier, which serves as a reservoir for Atlanta, expressed alarm about the record-breaking decrease in the lake’s water levels. Even though the drought has long ended, its effects made an impression among who live along the shores of Lake Lanier. Under intense local pressure, federal, state, and local officials continue to explore ways to ensure the lake maintains a sufficient water level to support recreational use, which will also preserve property values. At the same time, officials wrangle the legal issues associated with water usage at stake, the population of the City of Atlanta continues to grow along their demand for fresh water. The need for innovation solutions for the area’s current and future water supply issues is clear.
Biotechnology Provides an Innovative Approach to Water Reclamation and Reuse at Emory
The Water Hub at Emory provides a low-cost approach to water management with minimal environmental impact. Source: Emory University
The Facilities Management Division of Campus Services at Emory University, in collaboration with the privately-owned commercial water reuse and reclamation company Sustainable Water, recently launched the first WaterHub® in the United States on Emory’s campus, located in the city of Atlanta. This water reclamation and reuse system relies upon microorganisms living in a complex ecosystem to capture and treat wastewater for use in the campus’s steam and chilling systems as well as to flush toilets. University officials report that the WaterHub® has the capacity to treat 400,000 gallons of water a day, which enables the system to meet 40 percent of the campus’s water needs. As a result, the campus will reduce its draw from the municipal water supply by 146 million gallons annually, thus decreasing some of the stress on the small, but contentious, Alabama-Coosa-Tallapoosa and the Apalachicola-Chattahoochee-Flint River watersheds.
How the WaterHub® Works
The WaterHub® is a closed water reclamation and reuse treatment facility that offers the advantage of a small footprint when compared to traditional wastewater treatment plants. By cultivating beneficial bacteria and other microorganisms that degrade pollutants and excessive nutrients, the WaterHub® eliminates the need for chemical treatments, which makes the system not only cost-efficient but also environmental friendly. Additionally, since the WaterHub® relies primarily on gravity to move water through the system, this wastewater treatment method requires little energy to operate. The compact size of the WaterHub® makes it well suited for use in urban areas.
The steps involved in the 18-hour water treatment process are as follows:
1. Water collected in the campus sewer system flows to the Waterhub® facility.
2. Filters remove trash and large pieces of debris from influent prior to entering the system.
3. The water moves through the greenhouse system cascading through aerobic, anoxic, and anaerobic treatment chambers.
4. The water then flows through indoor hydroponic gardens where free moving plastic pellets and/or engineered textiles add to the surface area of the root systems that serve as the home for 2,000 to 3,000 micro-organisms.
5. Water treatment continues in outdoor hydroponic gardens.
6. The final step of the process involves using ultraviolet light to disinfect the water to ensure it is free from all pathogens.
7. While some of the treated water is pumped into campus non-potable systems for immediate use, a portion of the water funnels into a 50,000-gallon storage tank for emergency use.
In addition to the greenhouse process, the WaterHub® facility also includes Demonstration Reciprocating Wetlands that mimic the ebb and flow of water through tidal wetlands. This system also uses micro-organisms to treat the water. The developers of this process envision it used in rural areas and in the developing world where relatively large expanses of land are available. The water treated by both processes meet federal, state, and local water quality and safety regulations.
Diagram of the WaterHub and Demonstration Reciprocating Wetland water treatment processes. Source: Emory University
The developers of the WaterHub® chose plants that had dense root systems to maximize the surface area on which micro-organisms could grow. In addition, they selected plants that were low maintenance.
Some examples of the plants used in the WaterHub® hydroponic gardens and the wetland system include the following:
• Angel Trumpet
• Scarlet Rose Mellow
• Giant Call Lily
• Native Water Canna
• Umbrella Palm
• Mexican Papyrus
• Elephant Ear • Mexican Petunia
• Common Rush
• Arrow Annum
• Duck Potato
• Water Willow
You can learn more about the WaterHub® design and process by watching this video:
Additional Benefits of the WaterHub® Water Reclamation and Reuse Facility
Since the WaterHub® is a closed system, it is free from the noxious odors associated with traditional water treatment plants. In addition, the gardens provide a pleasant oasis for study and relaxation for students and visitors to the Emory campus. The facility also serves as a living classroom and research lab for not only engineering students but also those enrolled in Emory’s undergraduate and graduate law, public health, science, and environmental programs.
The financing for this project used a Water Purchase Agreement (WPA). According to this contract, Sustainable Water assumed the costs of developing and building the facility, while Emory committed to a ground lease and agreement to purchase the water. During the next two decades, the school anticipates saving millions of dollars on water costs.
By using an onsite water treatment facility that functions independently of the Atlanta Municipal water system, Emory not only reduces stress on the city’s aging water infrastructure but also insulates itself from external system failures. For example, if a water main bursts off-campus, students, faculty, and staff can continue with their activities since the university’s water needs are met by an independent system. Before the WaterHub® went into use, the school would have to close if a disruption occurred in the municipal water system.
While traditional water plants can take years to build and bring online, the WaterHub® typically takes six to twelve months to construct and two to four months to commission.
Applications of the WaterHub® Technology
Some examples of other places WaterHub® technology may be used include:
With water scarcity issues posing challenges for individuals and both public and private sector entities, innovative water management strategies like the WaterHub® will be in high demand.
What are your opinions about the use of WaterHub® technology? What challenges do the developers face in encouraging widespread demand for their water treatment systems?