Chalk cleanup for overflow at GIWA water works
A half-million gallons of rainy sewage leaked onto the Gasparilla Island Water Authority plant grounds after Hurricane Debby. The spill was at 2:05 a.m. on Monday, Aug. 5. It did not go into the Bayou or Cross Island Canal, nor did it hit the golf course or GIWA retention pond.
“We had the choice of putting water down the injection well that wasn’t treated,” said GIWA Executive Director Ron Bolton of the decision to let it run onto the property. Because of the time of day and low usage, the wastewater contained little actual sewer waste.
“The first day was tidal,” Bolton said. “The second day was rain.” The notice is as follows:
“Gasparilla Island Water Reclamation Facility experienced significantly high sanitary sewer flows during the Tropical Storm Debby event and a SCADA failure early Monday (2:00 a.m.) that resulted in our EQ Tank overflowing with a combination of storm water and untreated influent. We were able to reset the SCADA system on Monday morning, but the influent flows were not back to reasonable levels until Tuesday mid-morning. … All of the spill remained on site and was treated with lime.”
Bolton said that they have currently reduced treatment capacity, as they are switching to an advanced membrane system of filtration. The extra water that hit the system during Debby came in through pipes in the sewer system that are not tight. A follow-up letter to Alexandria McSurley of the Florida DEP stated that the gallons of “highly diluted influent sewage” spilled over the EQ tank walls “over a 16- hour period.”
To deal with the spill, the GIWA staff used deactivated lime to disinfect the area and, according to the letter, “manually controlled the lift stations to reduce the flows to the plant until we could meet the demands.”
Much of what came through the system was at first high tides, and then rainwater. A GIWA spreadsheet entitled Percent of Effluent Used for Reuse keeps track of how much of the plant’s cleared water goes to the nearby ponds or is injected back in aquifers.
The Wastewater Malfunction Abnormal Event Report form showed the official discharge as 534,000 gallons. Debby passed by Gasparilla Island and hit the Steinhatchee area at 7 a.m. on Aug. 5, 2024.
The Boca Beacon was alerted to the spill by Calusa Waterkeeper Codty Pierce, who received the email about it on Aug. 29 from the state. Bolton said that he had reported the spill by phone, as is required if the spill is over 1,000 gallons. He also followed up on Aug. 6 by email and letter.
The issue was that the state reporting system only triggers a warning blast when items are entered electronically. It was the updating of that information that triggered the warning notice to the public.
Currently the plant uses old biological sewer treatment, which has a capacity of 560 gallons a minute. The new membrane filtration, using a DuPont system, will be able to process 1,180 gallons a minute. That plant is fully built and working, but is not yet using effluent. GIWA had hoped to have the new treatment online now, but when they could not get a start window in the spring, they decided to wait until after hurricane season, when there is the threat of having to shut it down, and restart. Currently they are running tests with the new system using clean water for a January launch.
