Opportunity
Wakulla Springs, south of Tallahassee, is said to be the longest and deepest submerged freshwater cave system in the world.
In 1850, a woman named Sarah Smith spotted the bones of an extinct mastodon resting on the bottom. Since then, scientists have found the remains of prehistoric horses, dugongs, and saber-toothed tigers under the waters, as well as bone and stone implements left by early humans.
Several early Tarzan movies starring Johnny Weissmuller were filmed at Wakulla Springs. Now protected by the Edward Ball Wakulla Springs State Park, the area remains a habitat for alligators, manatees, white-tailed deer, river otters, bald eagles, ospreys, and a variety of other birds.
The nearby Thomas P. Smith Wastewater Treatment Facility helps serve 200,000 of the 275,000 residents of Leon County. In order to increase the plant’s capacity, meet Advanced Wastewater Treatment (AWT) standards, and help protect the waters of Wakulla Springs, the city of Tallahassee took on the largest wastewater project in its history.
Solution
In 2008, the engineering and construction company MWH Global agreed to provide Construction Management at Risk services to the project. The city had never before used this delivery method, which requires the construction manager to deliver the project within a guaranteed minimum price. (See video for more details.)
Mott MacDonald joined the project team, and as the team member with the largest local presence, we furnished the deputy project manager, handled permitting, and took responsibility for the design and construction administration of the following facilities:
- New headworks
- New wet weather flow equalization
- New primary clarifiers
- New primary effluent and primary sludge pump stations
- Septage/FOG (fat, oil, and grease) receiving station
- Chemical feed systems
- Electrical systems
- Addition to operations building
The plant’s three treatment trains were converted to the 4-stage Bardenpho process, which reduces concentrations of nitrogen and phosphorus in effluent with almost no added chemicals.
Outcome
Since the project was completed in 2015, the water effluent discharged from the plant is among the cleanest in the state of Florida. The environment of the Wakulla Springs State Park, which is listed on the National Register of Historic Places and designated as a National Natural Landmark, will receive an added measure of protection.
The plant will be prepared to operate far into the future, avoiding the necessity for expensive upgrades.