Beaches from El Segundo to the southern end of Playa del Rey were reopened to swimmers on Wednesday after a 17-million-gallon sewage spill shut them down on Monday and Tuesday.
A power outage Sunday at the Hyperion Water Reclamation Plant caused untreated sewage to spill into the ocean, Los Angeles County Supervisor Janice Hahn tweeted.
Hyperion Executive Plant Manager Timeyin Dafeta issued a statement Monday afternoon saying that on Sunday afternoon, the plant "became inundated with overwhelming quantities of debris, causing backup of the headworks facilities. The plant's relief system was triggered and sewage flows were controlled through use of the plant's one-mile outfall and discharge of untreated sewage into Santa Monica Bay."
Dafeta said the 17 million gallons of sewage — about 6% of a daily load — were discharged as an emergency measure through the one-mile outfall to prevent the plant from going offline and discharging more raw sewage. Normally, treated sewage is discharged through the five-mile outfall.
"Thanks to these efforts, and significant equipment improvements that have been made in recent years in partnership with several environmental groups, the amount of flow into the ocean was mitigated and the plant remained online," Dafeta said.
"These improvements included the reconfiguring of in-plant storm basins to pump sewage back into the plant in cases of emergency; screens were installed on all catch basins to prevent untreated debris from entering the storm drains and out to the ocean; and a Headworks Bypass had been installed to prevent raw sewage overflowing out of the Headworks building and into the street."
Dafeta said LA Sanitation & Environment is following protocols for notifying regulatory agencies and the California Governor's Office of Emergency Services about the spill.