New Lift Station Designed to Withstand Category 3 Storms
By Thomas Renner
Sarasota County sits on Florida’s Gulf coast and is home to 380,000 people, according to the 2010 census. Gulf-side sewage management has been a long-time challenge for the county, as residents had complained for years about foul odors and spills frequently occurred– indeed, in 2004, 48 spills were reported. A national environmental group estimates sewage leakage into county waterways ranged from 618,663 to more than 1.1 million gallons.
Susannah Lindberg, the Florida program coordinator for the nonprofit environmental group Clean Water Action, told the Herald-Tribune newspaper at the time: “That’s the point of our report: No one knows,’’ she said, commenting on the wide range of estimates.
One particular area of concern for the county was Lift Station 7. Originally commissioned in the 1980s, by 2004 it had become apparent that the station was nearing the end of its useful life when it leaked more than 500,000 of raw sewage into the Hudson Bayou. The waterway is in the heart of one of Sarasota’s most affluent neighborhoods and an estuary of the ecologically-sensitive Sarasota Bay. “Hudson Bayou suffers the indignities of many years of urban runoff,’’ said Sarasota ecologist Rob Patten to YourObserver.com in 2013.
Neighbors experienced “rotten egg” smells for years prior to the sewage spill, but city officials were slow to address the issue or to communicate with local residents. When an electrical shortage caused pumps to malfunction leading to another spill in February of 2005, the city was forced to find a long-term solution.
Earlier this year, Sarasota city officials wrote the last page on the Lift Station 7 story. A new building, Lift Station 87 — at a final cost of $67 million, according to YourObserver.com, or more than eight times the original budget — will manage about 33 percent of the city’s wastewater flow when all of the connections to the community come on-line, which is expected to be complete by July 2021. The 16-year saga of the construction of the new wastewater system includes dramatic project revisions, fired contractors, lawsuits, and multiple city officials who have come and gone.
Lift Station 87, designed by McKim & Creed, will handle 9.5 million gallons per day in a two-story building in Sarasota’s Luke Wood Park. The scope of the project was technically complex and all-encompassing.
The station was constructed to withstand a Category 3 hurricane storm surge and to allow Sarasota Memorial Hospital and other critical designated storm shelters to remain in operation after a storm event. Maintaining operations during hurricanes was an important concern for city officials and residents as a hurricane or tropical storm brushes the city, on average, every other year. The project involved an evaluation and design of the system, a lengthy microtunneling plan, lift station construction, roadway resurfacing, and park restoration.
Workers installed new sewer mains along with reclaimed water to provide the area with an environmentally-friendly source of irrigation water, and aging water mains were replaced to improve water pressure.
Learning from the lack of communication from the Lift Station 7 issues, city officials kept residents informed of project updates with a website dedicated to the project that included frequently asked questions, meeting notes, and important documents. Citizens could choose to receive email notifications about project updates.
No one could dispute the fact that a new lift station was sorely needed and long overdue, and all agreed that the project would tremendously improve the city’s quality of life. The path to get there, however, was nothing less than torturous. Residents grew weary of the project timeline and frustrated by ongoing construction and budget overages, and while the project is now complete, no one in Sarasota is taking a celebratory victory lap.
The spill in February 2005 proved to be the final straw for city residents, who were not told of the 2004 spill until the 2005 event. In August of 2005, six employees of the public works department were demoted, reprimanded, or forced to retire, and by 2007, City Manager Michael McNess resigned, in large part due to the mishandling of the lift station.
With the project behind them, city officials are looking back to understand why the project went so long and over-budget. “I think we need to own up to it and explain to the community what happened so that we and future commissioners don’t have the same problem or learn from those mistakes,’’ Commissioner Hagen Brody told the Herald-Tribune last September.
In 2008, the city approved the relocation of Lift Station 7 from Pomelo Avenue to Luke Wood Park. After the two major sewage spills, the state Department of Environmental Protection imposed a 2011 deadline for the city to move the station from Pomelo Avenue, which is about a half-mile from the park. Despite some public opposition, the Luke Wood Park option was thought to be the most cost-effective and time-efficient solution.
The city estimated the cost of the new facility at $8.5 million. The city awarded Westra Construction Corporation a $9.6 million contract in February 2011, and work began in June with an estimated completion date in 2012. AECOM served as the project engineer.
Construction began in June 2011, but another spill resulting from construction alarmed residents and city officials. In August, a contractor accidentally broke a 14-inch force main, causing an estimated 200-gallon sewage spill into the Hudson Bayou.
A New Team
In November of 2012, the city terminated its contract with engineering consultant AECOM. Westra was also removed as the contractor. The potential of another sewage spill if work had continued could have been catastrophic, as workers were on the verge of drilling into the northern support slab of the Osprey Avenue Bridge over the Hudson Bayou, according to a report. “We’re very lucky we didn’t have a catastrophe with our utility department,’’ then-Mayor Shannon Snyder said in 2014.
McKim & Creed replaced AECOM in August 2013, and construction began in 2015. With a budget of $32 million – about 4 times more the original plans – the company proposed a new above-ground structure that could withstand hurricanes.
A bigger issue, however, remained with digging near the bridge. Engineers decided a microtunnel below the bridge needed to be placed eight feet further down to avoid impacting the structural integrity of the bridge. Engineers believed the bridge might have collapsed in the soft silt base surrounding the bridge without the deeper microtunneling. Previous work done by contractors had to be done over. The project moved back to square one.
“The invert elevation of the 36-inch main was lowered 8 feet to avoid interference with existing bridge abutment and to minimize potential impacts to the environment during drilling,’’ McKim & Creed wrote on its website. “Phase 1 also included a review of the previous lift design and recommendations to increase reliability, improve worker safety and minimize operational issues.”
After its evaluation, McKim & Creed proposed several important changes to the project. The first was to “harden” the lift station to withstand Category 3 hurricane storm surges.
The more critical assessment, however, was digging eight feet farther down with the microtunnel under the Osprey Avenue Bridge. The microtunneling process finally began in January of 2017. “This is where the rubber meets the road,’’ Mitt Tidwell, Sarasota’s Utilities Director at the time, told the Sarasota Herald-Tribune. “We scheduled this work first to protect the city’s investment and minimize risks.” The process included the closure of the Osprey Avenue Bridge in Sarasota in July of 2016. The bridge re-opened in June 2017.
“The only choice was to go under the bridge, and microtuneling was the only option,” McKim & Creed Project Manager Robert Garland, PE, said in a radio interview.
Microtunneling is a remotely controlled process that is frequently used in soft, unstable soils. Crews dig sending and receiving pits to install a new sewer pipe. A microtunnel boring machine is dropped into the sending pit and cuts a hole underground to the receiving pit, without disturbing the surface above. A jacking rig, functioning similar to a jack hammer, pushes the new sewer pipe in place. Garland said the process is slow, progressing about 20-40 feet per day.
“You’re underground, chewing through rock, under a historic bridge, and in an environmentally sensitive area,’’ he said. “We went about this in a methodical way.”
Wastewater is carried through a 36-inch PVC pipe in the microtunnel, and it is encased in a 60-inch casing. “We put the steel casing in first, which is the wall of the tunnel,’’ Garland said. “Inside that casing will be the pipe that carries the wastewater. It helps us in the construction, but if there is any failure of the pipe, it is contained within that casing.”
New Lift Station
While crews worked on the microtunnel, other teams started construction of the lift station in October 2017. Work included the demolition of existing structures and the construction of a state-of-the-art odor control facility. The fully-enclosed building minimizes the impacts of routine operation and maintenance, according to the city.
The building includes HVAC and equipment exhausts in the towers, and the two-story building was built over a new, 50-foot deep wet well. “We’ve spent the past year constructing the equivalent of a five-story building underground and below sea level,’’ Sarasota Utility Director Bill Riebe said in a press release in August 2019. “Construction of the wet well and connection of new, micro-tunneled 36-inch gravity sewer to the wet well piping has been technically complex.”
PCL Construction installed 15 doors from BILCO in the lift station. The doors were manufactured in a wide range of sizes and allow access to vaults, pipes and pumps in the wet well. The floor doors are constructed from aluminum with stainless steel hardware for corrosion
resistance and are reinforced for H-20 loading to withstand the force of heavy equipment vehicles used at the facility.
“The doors are durable, and they are a good product for this application because they are aluminum and won’t be as impacted by corrosive gases and water,’’ said Cory Westphal, an Assistant Project Manager for PCL. “It was a fairly standard installation except that they were installed before the building was finished. The building was built around the doors.”
PCL ordered the doors through Building Specialties of Bradenton, which worked with them to manufacture special sizes. “BILCO was selected because they had the capability to make very large hatches,’’ Westphal said. “Competitors had difficulty building the sizes we needed and meeting the loading requirements. The ability to make them that large and meet those requirements was essential. They were prepared because they build doors like this frequently and they knew how to do it.”
A Price to Pay
Initial estimates had projected the overall cost of the project at $8.5 million. The change in plans, including the building of the hurricane-resistant lift station, resulted in a dramatic escalation in costs.
Estimates increased as the project moved along, beginning at $27.1 million in 2014, followed by $32 million in 2015 and $54.1 million in 2017, according to YourObserver.com. The news outlet reported in an article last year the city estimates a final $68.5 million price tag, including $48.6 million for planning and construction.
City officials had hoped to recoup as much as $20 million from legal settlements, but in November of 2018 a jury ruled the engineering firm did not have to pay any damages. The jury also said the city breached the contract with Westra, and was ordered to pay $686,233 in damages. The city paid $10.1 million in legal fees for the project, according to the news outlet. Sarasota city officials and McKim & Creed declined interview requests.
Some residents in Sarasota wondered aloud during the long course of construction whether they would ever see the completion of the project. The process was extraordinarily long and complicated, but the end result should provide a long-term solution to a problem that has vexed the city for a generation.
A Big Lift For Florida Community
What: Lift Station 87 in Sarasota, Fla. is a new above-ground station with a 9.5 million gallon per-day capacity.
Why: The project is necessary to improve the wastewater system and mitigate overflows due to aging infrastructure and equipment. It will replace Lift Station 7, which will be decommissioned and the site will be restored and landscaped to its park-like setting. The new station will handle about 33 percent of the city’s wastewater flow.
Hurricane-proof: The two-story building was designed to withstand the impact of a Category 3 hurricane. The design will allow Sarasota Memorial Hospital and other critical designated storm shelters to remain operational after a storm. City officials directed the project engineer, McKim & Creed, to bring critical equipment above ground to a height above Category 3 storm surge elevation.
Custom floor doors: 13 floor doors from BILCO were installed in the project, and include factory-installed fall protection grating. The doors were customized to meet unique size requirements.
Did you know? Sarasota has been impacted, directly or indirectly, 36 times in the last 146 years by hurricanes. The city is brushed or hit by hurricanes every 2.16 years.
Thomas Renner writes on building, construction, engineering and other trade industry topics for publications throughout the United States.