Hurricane Harvey took aim at one of the nation's most industrial regions, releasing a stream of toxic pollutants from chemical plants, refineries and Superfund sites in Texas. But when its bigger sister Irma slammed into Florida, environmental alarms rang over a different kind of discharge: raw sewage.
Millions of gallons of poorly treated wastewater and raw sewage flowed into the bays, canals and city streets of Florida from facilities serving some of the nation's fastest-growing counties. More than 9 million gallons of releases tied to Irma had been reported as of late Tuesday as inundated plants were submerged, forced to bypass treatment or lost power.
Such overflows, which can spread disease-causing pathogens, are happening more often, as population shifts and increasingly strong storms strain the capacity of plants and decades-old infrastructure. The Environmental Protection Agency estimated last year that $271 billion is needed to maintain and improve the nation's wastewater pipes, treatment plants and associated infrastructure.
"There's no sewer system in the world that can be built that's completely leak proof," said Nathan Gardner-Andrews, chief advocacy officer for the National Association of Clean Water Agencies. Plants generally are designed to handle twice their normal capacity, but "when you get some of these rain events and you're talking four to six to eight inches of rain in an hour, the engineering is such that you cannot build a system to hold that capacity."
A treatment facility in Clearwater, Florida discharged 1.6 million gallons of wastewater into a creek, according to filings with the state's Department of Environmental Protection. The incident, which occurred after a power line snapped, was just a trickle compared to a 30-million-gallon discharge of raw sewage after Hurricane Hermine caused a pump failure in 2016, said David Porter, the city's public utilities director.
That scene was replayed across the state this week, as electrical outages caused lift station pumps to stop running in St. Petersburg and Orlando, prompting at least 500,000 gallons of overflows. A pipeline broke in Miramar, Florida, sending sewage spilling across a parkway as contractors hunted for the rupture. And operators of a Miami-area wastewater treatment plant blamed a power outage for 6 million gallons of sewage released into Biscayne Bay.
Late Tuesday, there was no visible sewage or garbage in the Biscayne Bay water along Brickell, Florida, but in nearby Bayfront Park, the air was heavy with a foul odor.
As wastewater treatment lagged, utilities across the state warned residents to boil water before drinking it. The U.S. Environmental Protection Agency said it has deployed specialists to Florida to help get wastewater systems back online.
Estimated releases of untreated and poorly treated wastewater tied to both Irma and Harvey are expected to continue climbing. Even Hurricanes Hermine and Matthew -- modest by comparison to this season's double whammy -- forced the release of some 250 million gallons of wastewater without full treatment between Aug. 31 and Oct. 15, 2016, according to a report by the Florida Department of Environmental Protection.
After Hurricane Sandy ravaged the northeast U.S. in 2012, damaged treatment plants and pumping stations caused untreated sewage to flow into local waterways for weeks. All told, facilities in the eight states hardest hit by the super storm released 11 billion gallons of untreated and partially treated sewage, according to one assessment.