Sludge contained on site
On the night of Jan. 24, approximately 16,000 gallons of processed sewage sludge spilled from a holding tank at the City of Sarasota’s Wastewater Treatment Plant on 12th Street in Sarasota, city staff has notified the Florida Department of Environmental Protection (FDEP).
“The spill was contained on site by the quick actions of operations staff,” the report filed with FDEP explained. “The area was vacuumed up, hosed down and treated with lime,” the report added.
The incident began at 7:30 p.m. on Jan. 24 and was over by 8 p.m., the report noted.
The nonprofit Center for Food Safety explains, “Sewage sludge is a product of wastewater treatment. Wastewater and stormwater enter the sewage system and flow into wastewater treatment facilities, where the solid wastes are separated from the liquid wastes through settling. At this point, they are processed and ‘digested,’ or decomposed by bacteria. These separated processed solids — sewage sludge — contain numerous known and unknown hazardous materials. This includes everything that is flushed into the sewer system, including: household, medical, chemical, and industrial waste; chemicals and metals that leach from the sewer pipes themselves; and novel materials that are created in the wastewater treatment plant as a result of the combination of chemicals and organic compounds present.”
The City of Sarasota facility operates at Advanced Wastewater Treatment (AWT) status, city officials point out. That means that, following treatment, the wastewater has far lower levels of nutrients such as nitrogen and phosphorus.
City staff’s report to FDEP says, “A gasket on a flanged fitting on one of the sludge pumps failed. The failure allowed sludge stored in the sludge holding tank to flow from the tank into the pump room and out onto the treatment plant grounds. Utility crews were called in to assist operations staff in containing the spill, shutting valves at the storage tank and cleaning up the site.”
The Instrumentation Tools website points out that a “pipe ‘flange’ is a ring of metal, usually welded to the end of a pipe, with holes drilled in it parallel to the pipe center line to accept several bolts. Flange joints are made pressure-tight by inserting a donut-shaped gasket between the flange pairs prior to tightening the bolts. Gaskets are manufactured from materials softer than the flange material. When sandwiched between a pair of flanges, the gasket will be ‘crushed’ between them to seal all potential leak paths.”
The city facility is located at 1750 12th St.