Serving the Yellow River basin in Georgia, this $245-million upgrade allows Gwinnett County to divert, consolidate and treat the flow from six aging wastewater treatment plants into a new facility, saving more than $2.4 million in annual operating costs.
The project was designed and built in overlapping phases to minimize the construction schedule and keep the existing water reclamation facility in operation. All existing plant facilities were demolished and new advanced treatment facilities and systems were constructed atop the old site while maintaining uninterrupted plant operations.
The facility's new treatment processes include influent pumping, first-stage screening, grit removal, primary sedimentation, emergency storage and equalization tanks, second-stage screening, biological nutrient removal, membrane biological reactors and ultraviolet disinfection. Odor-control measures such as enclosed tanks and air scrubbers help make the facility a good neighbor. Treatment residuals are conveyed via force main to a regional processing facility, where the resultant off-gas is used to generate renewable electricity.
The plant is controlled via a new LEED-Gold operations building, the first certified structure for the county's Dept. of Water Resources.
Another first for the county was the scale of a massive concrete pour for a 20-million-gallon prestressed storage tank that required the continuous delivery of one concrete truck every two minutes for an entire 14-hour period. The careful coordination was repeated for a second duplicate tank.
The successful phasing relied upon an integrated project delivery approach, reinforced when the entire team co-located in a field office at the site. That teamwork was tested when, in September 2009, the Yellow River topped its banks during a 500-year flood that damaged the facility's existing pump stations. The new influent pumps hadn't been tested yet, but the team worked around the clock to accelerate their startup. As a result, Yellow River was up and running within three days, when most other Atlanta treatment plants were out of service for weeks, if not months.
Owner: Gwinnett County Dept. of Water Resources, Lawrenceville, Ga.
General Contractor: PC Construction, Lilburn, Ga.
Construction Manager/Lead Design: CH2M Hill, Atlanta
Civil Engineer/Architect: Precision Planning Inc., Lilburn, Ga.
Structural/MEP Engineer: Jacobs, Norcross, Ga.
Submitted by CH2M Hill