Treated sewage was leaking into the Barnegat Bay for at least six weeks — and potentially years longer — before an outfall pipe was repaired last week.

Each day, some 23 million gallons of wastewater travel the 3½ miles from the Ocean County Utilities Authority treatment plant, in the Bayville section of Berkeley, through this underground, 54-inch-wide outfall pipe that voids into the Atlantic Ocean.

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A spokeswoman for the New Jersey Department of Environmental Protection said the utility initially measured the flow coming out of the 1-inch cavity at 50 gallons per minute.

That would be equal to 72,000 gallons per day, or the equivalent of 4½ Olympic-sized swimming pools of sewage over the course of the six weeks that the leak was active.

Observers and regulators do not regard this leak as a public health threat.

The wastewater involved is what drains down our sinks, showers and toilets before winding its way through the treatment process. The sanitized sewage was bound for the open ocean, in accordance with state law, but a fraction of the “treated secondary effluent” leached into the bay, which has been rebounding in recent years after decades of problems with pollution.

What happened?

The wastewater was emanating from a 1-inch hole in the steel pipe, which OCUA officials suspect to be the result of corrosion, about 1,200 feet east of the beach at the end of Allen Road. The failure was initially discovered by the authority on Oct. 9.

Excavation and repairs to the pipe, which is buried seven feet under the seabed, are ongoing and should be finished by the end of the week, according to Keith Marcoon, executive director of the OCUA. The leak itself was sealed on Nov. 20, he said.

“From Hour 1, the OCUA certainly followed all protocols prescribed by the DEP,” Marcoon told the USA Today Network-New Jersey on Monday.

The state DEP issued an informal enforcement order on Nov. 20 for "unpermitted discharge of secondary treated effluent to Barnegat Bay," according to department spokeswoman Caryn Shinske, who offered no criticisms of OCUA's response.

Bay watchdogs called OCUA officials "responsible" and "highly professional" but also urged them to inspect the pipe more often and to prepare for its replacement.

"For whatever reason, there have been some corrosion holes in this pipe," said Stan Hales, the director of the Barnegat Bay Partnership. "This isn’t the first time this has happened."

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What's next?

About 96 percent to 97 percent of pollutants and suspended solids are removed from the wastewater through the multi-step cleansing process, according to the OCUA.

Before it is released, this wastewater is tested for bacteria and those results regularly come back well below the threshold where, for example, contact through swimming would represent a health risk, said Robert Shertenlieb, the OCUA's senior director of operation and maintenance.

It had been more than 10 years since the last leak was discovered in this pipe, following a rash of four leaks in three years — ending in 2006 — that were patched on that same stretch under the bay between Bayville and South Seaside Park.

But the integrity of this 40-year-old pipe hasn't been tested since December 2012, as inspection is only required every five years. In theory, the gash in the pipe could have been leaking sewage into the bay for nearly six years before it was noticed.

“It is concerning that they are only testing the pipe every five years for leaks," said Britta Wenzel, executive director of the conservation group Save Barnegat Bay. "I don’t feel like that is adequate given the age of our infrastructure and the fragility of the ecosystem.”

Marcoon didn't disagree, saying that the OCUA would "consider a more frequent interval" of testing and had already engaged experts to talk about "rehabilitation and replacement options" for the Bayville plant's only outfall pipe, which has a 50-year expected lifespan.

That such a reaction has been prompted by a hole just bigger than a quarter is a sign of how far we've come since the 1960s, when nearly 50 municipal plants were discharging sewage into the bay after only rudimentary treatment.

“That poorly treated sewage many decades ago contributed to impairment of our surface waters," Marcoon said. "That’s what prompted the Ocean County Board of Freeholders to create the OCUA.”

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Russ Zimmer: 732-557-5748, razimmer@app.com, @russzimmer