Built in 1913, Sarasota, Florida’s historic Hover Arcade served at various times as an ice cream parlor, movie theatre, fire department and even City Hall. The Hover Arcade’s architectural appearance was used for inspiration in the design the exterior of Lift Station 87. This was to help preserve the community’s history.
Sarasota’s prime location on Florida’s gulf coast means the city’s world class beaches come with the seasonal threat of hurricanes. According to Eric Chavez, project manager for PCL, the threat of storms was top of mind during the building’s design process.
“The station is rated for a hurricane category 3 storm surge, which is one of the worst floods you’ll see during hurricane season,” says Chavez. “The generator is on the second floor, which is really not heard of for lift stations.”
Housing major electronical equipment on the second floor means the station can resume operations as soon as storm flooding recedes. This function could prove critical in the event of an emergency as Lift Station 87 also serves nearby Sarasota Memorial Hospital and other storm shelters.
“Having all the major electrical equipment on the second level means as soon as a storm surge recedes, the lift station can go right back to working,” Chavez says, whereas ground-level electronical equipment would be damaged and need to be replaced prior to the station becoming back online.
Chavez has been working construction in Sarasota for almost 20 years – in fact, his first project was less than two miles from the new lift station at the John Ringling Causeway, an overwater bridge project that connected Sarasota Bay to nearby St. Armands Key and Lido Key. Chavez’ knowledge of marine construction projects was invaluable during the lift station project.
A key part of the project was the construction of a cofferdam — a contiguous barrier, built in water, that allows water within the enclosed area to be pumped out. This creates a dry work environment for construction in aquatic environments such as lakes or rivers as well as inland locations with water tables higher than a building’s foundation, which was the case in Sarasota. To reduce the risk of water leaking back into the cofferdam, the barriers need to be drilled below the area’s water table.
“The water table on the site is very high, about 5 feet below the surface,” Chavez explains. “The cofferdam had to go 50 feet down, so it was a very big dewatering operation.”
At every step in the process of constructing the new lift station, PCL worked to be a good neighbor within the residential community where the project was taking place.
For example, the installation of sewer, water and reclaim piping typically requires local roads to be closed. PCL knew this would create major traffic headaches for locals, and worked with the Department of Transportation to obtain a temporary permit to install a deceleration lane used exclusively during the construction period. The additional road was used for deliveries and safe access while mitigating impacts to local traffic.
The team also kept the environmental impact of the new station in mind. Installation of a new 20-inch forcemain from the lift station was planned in areas of dense trees in the adjacent historic Lukewood Park. The design of the pipeline was developed collectively with the engineer, contractor, city and arborists to route the pipeline around the trees with consideration to minimize the impacts to the root systems, protect overhead tree limbs, eliminate both oversaturation from dewatering discharge and impacts to the highway nearby.
But perhaps the biggest litmus test of success would be how well the building was able to mitigate the odor of wastewater at the facility. The odor coming from the previous lift station was one of the main reasons the city took on the new project in first place.
Chavez explains that when raw sewage enters a lift station, sulfide gas is released as some of the sewage begins to decompose. To prevent hydrogen sulfide and other odiferous gases from escaping the station, PCL built a two-stage odor control system.
First, the gases are captured and then “trickled” through a biological process that removes the rotten egg smell typically associated with sewer gas. The treated air is then routed through activated carbon, which absorbs the final amounts of odor compounds in a process called “polishing.”
By the time the released air from the station is filtered back into the community, most if not all odor has been removed.
From navigating traffic patterns to odor mitigation, the careful planning and execution of the lift station project was intended to accomplish one main goal:
“Basically, we wanted the public not to know that there’s a wastewater station in their backyard,” says Chavez.
This vision was realized in some respects better than others.
“It says ‘City of Sarasota’ on the main doors in big letters,” says Chavez. “Right before we finished, City employees came by and asked if we could take them down.
“They were worried people would think the station was still City Hall.”