Failure of air release valve noted in one, with second involving pipeline damage
In two separate incidents — the first, which began on June 19; the second, on June 22 — approximately 22,300 gallons of sewage was spilled, Sarasota County Public Utilities Department staff has reported, with about 10,000 gallons recovered.
In regard to the first situation, which was reported near 2500 N. Honore Ave. in Sarasota, staff notified the Florida Department of Environmental Protection (FDEP) that an air release valve on a 24-inch sewer force main had failed. Approximately 3,500 gallons of sewage was spilled, county staff said. However, the workers were able to recover about 2,500 gallons of it.
Then, while one lift station was offline during the repair process, the report pointed out, approximately 800 gallons were spilled, with none recovered.
As Crane Engineering explains, “Air release valves are installed at the highest points in a pipeline where air naturally collects. Air bubbles enter the valve and displace the liquid inside, lowering the liquid level. When the level drops to where it no longer buoys the float, the float drops. This motion pulls the seat away from the orifice, triggering the valve to open and vent the accumulated air into the atmosphere. As the air is vented, liquid re-enters the valve, once again buoying the float, lifting it until the seat presses against the orifice, closing the valve. This cycle automatically repeats as often as necessary to maintain an air-free system.”
The cause of the second spill — at 7129 S. Tamiami Trail in Sarasota — was a break in an 8-inch force main.
The EPA provides this description of a sewer force main: “Force mains are pipelines that convey wastewater under pressure from the discharge side of a pump or pneumatic ejector to a discharge point. Pumps or compressors located in a lift station provide the energy for wastewater conveyance in force mains.”
The report on the North Honore Avenue incident said that it began about 6:30 p.m. on June 19 and that the situation was not resolved until 1:30 p.m. on June 20.
An aerial map shows the site is a short distance west of the rowing lake at Sarasota County’s Nathan Benderson Park, which is near University Parkway.
Staff had received a call about a sewage spill from a manhole near 2500 N. Honore Ave., the report added.
Crews were able to shut off a valve to stop that leak, the report to FDEP explained. Then the crews “removed the old ARV and installed a new one.”
However, the report added, the workers “had to temporarily stop [the] flow in the force main” to reach the valve. That necessitated their shutting off three lift stations “for a short period.”
Notifications for surrounding property owners and residents and clean-up were “proceeding per protocol,” the report added. “No surface waters were impacted,” it said, so no sampling was necessary.
In further details of the June 22 incident, on South Tamiami Trail, the county staff report noted that the Public Utilities Department received a call about “water coming up from the road at 7129 S. Tamiami Trail.”
That site, an aerial map shows, is southeast of the Ed Howard Lincoln car dealership on South Tamiami Trail in Sarasota. The incident occurred almost directly across from Buccaneer Drive.
Crews were able to isolate the sewer force main to stop that spill and make repairs, the report continued.
“Approximately 18,000 gallons of wastewater spilled, and approximately 7,500 gallons were recovered,” the report said.
“Crews worked tirelessly throughout the night diverting flow and hauling [sewage] from upstream lift stations to keep this line isolated for repair,” the report pointed out. “They hauled approximately 94,000 [gallons] from these stations to allow for time to make a successful repair.” (On the Sarasota County Government Facebook page, the total was put at 100,000 gallons.)
That incident began at 8 p.m., the report noted; it was not resolved until 11:15 p.m.
The report added that county staff members would be undertaking a “root cause analysis” of the 8-foot-long, longitudinal crack in the pipe.
Again, notifications about the incident were being provided to surrounding property owners and residents, and clean-up was “proceeding per protocol.”
That report did point out that sampling of nearby water bodies would be necessary.