On Sunday afternoon, debris streams flooded the Hyperion sewage treatment plant in Playa del Rey, forcing officials to take emergency measures to discharge 17 million gallons of sewage through a pipeline one mile offshore.

Timeyin Dafeta, executive plant manager of the Hyperion Water Reclamation Plant, New York City’s oldest and largest wastewater treatment facility, said in a statement on Monday that there are approximately 17 million gallons of wastewater — or 6% of the daily load — -It is discharged to a place one mile offshore, typically five miles, to prevent the factory from discharging more untreated sewage.

Dafeta said he believes this is the largest amount of untreated sewage discharged through a mile of pipeline in the past 10 years. On Monday morning, the water flow was directed back through the normal process, and officials were investigating the cause of the debris and repairing the damaged equipment.

"At this time, all traffic is processed through its standard processing procedures," Dafeta said.

The Los Angeles County Department of Public Health issued a recommendation on Monday urging residents to avoid swimming in areas near Dockweiler State Beach and El Segundo Beach. It said that water quality samples were collected on Monday morning to look for elevated bacterial counts, and the results are expected to be available within 24 hours.

Barbara Romero, director of the Los Angeles Department of Health and Environment, said that around noon on Sunday, a large amount of debris accidentally blocked the filter screen of the treatment plant opening less than an inch.

The factory manager tried to add screens to replace the blocked screens. They also tried to redirect the water flow to the rainwater drainage system in the factory—an alternative method of letting the water pass through the normal treatment process.

But after several hours of circulating water, the system is still overwhelmed.

Romero said: "The water flow has not subsided enough to pass the treatment process." "Of the 260 [million gallons] that came in, we ended up with 17 [million] unable to pass the treatment process."

So at around 7:30 in the evening, factory workers discharged wastewater into the ocean a mile away and 50 feet deep. The normal process leads the treated wastewater to below 190 feet.

Romero said that at 4:30 in the morning, the workers successfully used the recently installed channel to return the water to the standard treatment process.

Dafeta said that the last time the one-mile pipeline was used to discharge large amounts of wastewater was in 2015.

Dafeta said the plant subsequently used the mile-long pipeline to respond to emergency situations during heavy rains. However, the water flow also discharged garbage that had been dormant in the pipeline for many years, forcing the closure of Dockweiler Beach. He said that later that year, the plant was authorized by the Los Angeles Regional Water Quality Commission to use the pipeline during repairs to the 5-mile pipeline.

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Dafeta said that officials are not sure what caused the large amount of debris that caused the use of a mile of pipeline on Sunday, but due to improvements after 2015, the amount of wastewater flowing into the ocean has decreased.

"Why this amount and where it came from, we are still working to determine," Dafeta said. "It is the quantity and type of materials that cause screen problems."

In a statement, Los Angeles County Supervisor Janice Hahn said that she knew the plant could prevent a larger leak, but "we will need answers about how and why this happened."

The environmental organization Heal the Bay said in a statement that although debris such as tampons and plastic trash may breed bacteria and entangle wildlife when released into the ocean, “in this case, these debris seems to be leaking. It was successfully filtered out before. In the Bay Area."

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Leila Miller is a foreign correspondent for the Los Angeles Times in Mexico City. She joined the newsroom in 2018 and has worked in the criminal justice team for several years. She is also a member of the team of the 2020 Pulitzer Prize finalists, which reported on the Conception ship fire near the Channel Islands. Miller was born in Argentina but grew up in Los Angeles and graduated from Oberlin College and Columbia University School of Journalism.

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