Big Creek WRF expansion sets a landmark standard for sustainable treatment in Georgia

The county's history of success with membranes at its other North Fulton facilities only enhanced it's interest in pursuing the same equipment for the Big Creek WRF.

Beyond performance upgrades, the expansion prioritized sustainability and long-term resilience. The gravity-based hydraulic design eliminates most pumping needs, saving an estimated 40 million kWh over 20 years. Advanced systems, including S2EBPR technology, cut chemical use while enhancing phosphorus removal. A comprehensive odor control network – among the largest in Georgia – transformed the plant into a better neighbor for surrounding communities.

"Fulton County watned to be good neighbors and to address a long standing odor issue," Clark said. "The new odor-control system includes the covering of all treatment basins and maintaining them under negative pressure, vacuum conditions so that any odorous air is captured and routed to treatment."

The more than 270,000 scfm of air flow system uses a two stage process in the highest odor zones, headworks and primary clarification. The first stage are chemical scrubbers and the second is granular activated carbon contactors. The rest of the facility, Clark said, uses the GAC treatment for odor. This allowed the facility to meet higher odor standards and achieve no detectible odors at the site boundary.

"Community perception has shifted accordingly: what was once viewed as a nuisance — with neighbors famously dubbing the nearby grocery store 'Stinky Kroger' — is now seen as a modern infrastructure asset that respects its surroundings and significantly reduces off-site impacts," Clark said.

The team behind the project, led by Fulton County in partnership with Archer Western and Brown and Caldwell, delivered the project using a progressive design-build model that enabled early collaboration, cost transparency, and creative problem-solving. That collaboration proved critical as the project faced historic challenges – from COVID-19 disruptions and supply chain chaos to the complex geology of granite bedrock near the river. Despite those hurdles, the project remained on time and within budget.

"This collaborative working relationship established a strong foundation that proved to be invaluable during the COVID years," Clark said. "Without such a strong and trusting relationship that started early, navigating the challenges that COVID brought, including supply chain and hyperinflation, would have been much more difficult."

Innovations like deep structural slabs to route piping, reuse of more than 200,000 cubic yards of excavated rock onsite, and the strategic use of tower cranes all helped streamline construction while improving safety. Additionally, the forward flow of the plant is gravity-driven, including through the membranes, which has lowered operational costs. Energy and chemical savings were reduced through the use of ammonia based aeration control (ABAC) and the side-stream enhanced biological phosphorus removal (S2EBPR) system, respectively. Clark said that's not all that was considered, either.

"Currently, Fulton County is exploring the possible use of solar panels to further offset the electricity demand for the administration offices and laboratory," Clark added.

The project was completed in 2025, and the expanded Big Creek WRF set a new benchmark for sustainable, resilient, and community-focused wastewater treatment. Perhaps most important is the original goal; nutrient reduction to the Chattahoochee River, which improves the downstream health of the waterway for other communities.

"Our downstream neighboring utilities withdraw drinking water from the Chattahoochee River and provided potable water to over 2 million people," Clark said. "By reducing nutrient discharge, Big Creek helps maintain a cleaner, more stable source of water for these communities and utilities downstream, and enhances the ecological balance of the river."

In this way, Clark said Big Creek WRF is a demonstration that modern wastewater infrastructure can have its cake and eat it too by meeting growth needs and protecting the environment for the public.