City aerating Bethel Creek as part of cleanup effort after sewage spill

The city of Vero Beach has installed 10 aeration heads in Bethel Creek to try and accelerate cleanup of the creek in the aftermath of a major sewage spill last fall that dumped 3.2 million gallons of human waste in the narrow waterway lined with expensive homes.

The creek, which has little natural flow, smelled like a toilet for weeks after the spill and residents converged on City Hall demanding action, concerned about possible dangers to human and animal health and harm to their quality of life.

Rob Bolton, head of Vero’s water and sewer department, moved quickly to repair the broken sewer pipe, and put up warning signs to alert fishermen and boaters that the creek was contaminated. He also instituted a testing program to keep track of bacteria levels in the water, where manatees cruise in search of food and ocean-going yachts bob at backyard docks.

Scientists from the Ocean Research and Conservation Association in Fort Pierce conducted separate, independent tests in April as part of ORCA’s ongoing mission to study, protect and restore aquatic ecosystems in the Indian River Lagoon.

ORCA tested toxicity and nutrient concentrations in the sediment and throughout the water column, according to Dr. Beth Falls, the ORCA scientist in charge of the Bethel Creek project.

“I can say that Bethel Creek is among the worst areas we’ve tested along the Indian River,” Falls said.

With water contaminated enough at one point that it was dangerous to touch and high bacteria levels persisting for weeks after the spill, Bolton consulted with scientists from Florida Institute of Technology and eventually decided to try aeration, one of the standard methods used for treating sewage, because oxygen helps kick-start good bacteria that consume organic matter.

Human waste is harmful to recreational and environmentally sensitive waters not only because of dangerous bacteria like e-coli but also because sewage carries household chemicals and is loaded with nitrogen and other nutrients that feed harmful algae blooms that deplete oxygen levels and smother marine life.

The city bought 10 aeration heads and a compressor for $25,000, along with testing equipment that cost another $11,000, and the Bethel Creek aeration project got underway in June. It was powered up slowly at first, Bolton said, to ensure it wouldn’t churn up the thick organic muck at the bottom of the creek and release nitrogen and phosphorous that would spark an algae bloom.

The aerators now operate daily – on an 8-hours-on, 4-hours-off schedule – creating bubbly, foaming areas in the middle of the creek. Each pump is fastened to a base on the creek bottom and connected to an onshore compressor with a total of about 10,000 feet of hose.

Since the aeration began, the city’s weekly tests have shown some rise in oxygen levels, according to Bolton. “We monitor oxygen levels, salinity, temperature and total suspended solids, and we’ll do some additional testing next week,” he said. “The aeration is definitely helping.”

Bolton said the aeration will continue for nine months to a year, and, if the oxygen levels continue to increase, and “we get different ideas on how to handle the muck, we may go to 4 hours on, 7 hours off.”

Island environmental activist Judy Orcutt would like to see “more hard science” during the project period to determine whether aeration could be used to reduce muck and the algae-loving nutrients it contains in other parts of the lagoon.

“We don’t have that kind of data,” says Orcutt, who’s also concerned that the city’s entire wastewater system could be at risk from sea level rise, salt water intrusion and failures like the one that occurred in November, when a rusting sewer main that runs along State Road A1A sent a thick flow of untreated sewage into the creek.

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