Hyperion operating ‘sufficiently’
Plant still needs repairs, not at full strength, after near-disaster
Three weeks after flooding crippled the Hyperion Water Reclamation Plant and sent 17million gallons of sewage into the ocean, officials this week said the plant has been repaired enough to operate sufficiently, though sanitation employees also are working feverishly to fully fix the 144-acre complex before the traditional start of the rainy season.
That work is the first of multiple efforts Los Angeles Sanitation & Environment has undertaken simultaneously in the aftermath of what officials called a “nearly catastrophic” disaster.
Officials also are investigating why an abnormal amount of debris inundated Hyperion, causing the deluge, and assessing how to improve the plant to prevent future backups and flooding.
Those details came during a two-hour tour of Hyperion on Wednesday, which further illuminated the severity of last month’s crisis while also revealing that the plant remains at risk — both in the short-term and, potentially, in the future.
The tour also came a day before the Los Angeles City Council’s Energy, Climate Change, Environmental Justice and River Committee
discussed the crisis and its aftermath.
The committee unanimously approved a motion to have the Bureau of Sanitation report to the full City Council on what went wrong and what officials are doing to ensure it doesn’t happen again. There is not yet a time frame for when that discussion will occur.
Council members on the committee criticized the public for dumping trash in the sewers and flushing items down toilets that don’t belong there. They also hailed Hyperion workers for preventing a larger catastrophe.
“Our city employees saved the Pacific Ocean and the city from a much more catastrophic result,” Councilman Paul Krekorian said Thursday. “The source of this problem was not some failure by employees or of machinery, it was people doing stupid things.”
How the plant works
Treating wastewater is a complex and sometimes delicate process.
It begins at the toilet. When someone flushes their toilet, the waste flows into the thousands of miles of sewers L.A. Sanitation manages not only for Los Angeles, but also for 30 other cities with which the agency contracts. The sewage then flows into four reclamation plants L.A. Sanitation operates, though only the one on Terminal Island operates independently from Hyperion.
Hyperion, situated on Playa del Rey, is the largest water reclamation plant in the nation, according to L.A. Sanitation General Manager Barbara Romero.
The approximately 260 million gallons of wastewater Hyperion handles daily is about three times more than the next largest LosAngeles facility — the Donald C. Tillman Water Reclamation Plant, which serves a portion of the San Fernando Valley.
Once the sewage arrives at Hyperion, it goes to the headworks facility.
The headworks uses screen-like mechanisms to sift out trash, branches and other large debris, which get put on trucks and sent to a landfill. Hyperion fills up about 25 trucks each day, totaling 20 tons of trash, plant manager Timeyin Dafeta said. After the initial screening, the remaining sludge goes to a set of primary tanks, where it sits for about two hours, letting the remaining heavy solids settle at the bottom. Oil and grease float to the top.
The remaining wastewater is sent to a secondary reactor, where bacteria eats most of the leftover solids. Once that process is done, the wastewater is sent to the final clarifiers, which are 36 tanks that can hold 2 million gallons each. Those bacteria settle at the bottom and are eventually collected. Machinery also skims the oil and grease at the top of the wastewater.
At that point, the treated water gets sent down an outfall that travels 5 miles into the ocean.
The bacteria, as well as the solids collected from the primary tanks, are sent to giant, egg-shaped tanks called digesters. Bacteria there break down the solids, producing methane gas. Those digesters produce enough gas to generate 20 megawatts of electricity.
“To us,” Dafeta said, “that is precious gold.”
Plant overwhelmed
On July11, that process broke down, officials said, and remained hindered for about three weeks. The cause, Dafeta said, was excessive detritus.
The headworks has eight machines that rake out debris. Each can handle 133 million gallons daily. Typically, Dafeta said Wednesday, Hyperion operates only two at a time during the dry season and four when the flows double during storms, because some rain runoff makes its way into the sewers.
Things were calm in the morning on July11. Then came the trash. Steadily. Incessantly.
Two machines couldn’t handle the onslaught. Neither could four. Soon, all eight machines whirred at once. Until they clogged and stopped working altogether.
About 3 p.m., about three hours after the debris flow increased, the headworks began flooding. The wastewater spilled out of the headworks and ran through the streets of Hyperion. Drains in streets caught the water and recirculated it through pumps to keep the flooding down. But with the headworks shut down and more wastewater coming into the plant, the pumps couldn’t keep up.
Officials describe Hyperion as a city unto itself, with a network of streets on the surface and a series of underground passageways large enough for vehicles.
Soon, the wastewater overran the facility, above and below.
The headworks facility has a bypass that could have prevented the worst of the flooding, Dafeta said Wednesday. But sanitation workers couldn’t get into the facility. The waters lifted up the metal floor coverings that provide access to the conveyor-like mechanisms that operate the rakes and screens, he said.
And the water was too murky to see through.
“You fall through there,” Dafeta said about the coverless openings, “it’s over.”
So for hours, try as they might, Hyperion officials couldn’t stop the flood.
Officials faced an unenviable choice: Relieve the pressure by sending untreated sewage down the plant’s 1-mile outfall — which lets out much closer to the shoreline — or run the risk of Hyperion going offline.
Thursday, Dafeta described the consequences of the latter occurring to the City Council committee.
The waste “either would go into the ocean or back into people’s homes,” he said. “Sewage backing into homes, into streets and into the ocean.”
About 7 p.m. July 11, officials made their decision: They sent the untreated sewage into the ocean.
It did so until early the next morning, when the wastewater coming in was at its lowest level and the flooding in the headworks had subsided.
Hyperion had avoided a collapse of the Los Angeles sewer system. But the plant was scarred.
Assessing and repairing the damage
About 50% of the plant flooded, officials said. Water covered the streets. It rushed down the stairs leading to the underground passages, filling them like an indoor pool. By that time, officials said, all workers had moved to the surface.
It turned the excavated construction site of Hyperion’s planned Advanced Water Purification Facility into a mini-lake.
The basement and first floor of the effluent pumping station, which helps push the treated wastewater down the 5-mile outfall when the flow is greater than gravity alone can handle, was submerged.
Once workers pumped the wastewater out of the complex, the full extent of the damage — and the sheer volume of trash that built up — became clear.
Images from L.A. Sanitation showed the headworks, once the water was pumped out, covered in so much trash it looked like a restroom at a public park after a music festival.
The underground passages had visible water lines about 41/2 feet above the ground. The pumps that send sludge from the primary tanks to the digesters were damaged. Electrical equipment shorted out entirely.
Hyperion’s staff was able to get two of the headworks machines back online within a day. But the pumps needed to be replaced, their motors rebuilt, Dafeta said.
“We couldn’t move the sludge for about three weeks,” Dafeta said. The sludge sat there.
But the toilets kept flushing. And the sewers kept sending waste to Hyperion. So the sludge increased, with nowhere to go.
That, Dafeta said, is why a stifling stench has overwhelmed El Segundo residents and why wastewater that the local water quality board described as “partially treated” kept flowing into the ocean weeks after the crisis.
“The sludge had nowhere to go,” he said. “The digesters had no movement.”
Playing catch up
Multiple officials on Wednesday said Hyperion staff has worked 24/7 to get the plant fully operational. A log of the work, available on the L.A. Sanitation website, shows significant progress.
All eight screens at the headworks were online within three days of the flooding and one of the pumps that sends some sludge from the clarifiers to the digesters became operational a day later.
Other repairs, however, took longer.
Hyperion wasn’t able to send sludge from the primary tanks to the digesters until the end of July, according to L.A. Sanitation documents. Same goes for the system that thickens the sludge from the clarifiers before it goes to the digesters. And much work remains. The plant has 29 pumps that send sludge from the primary tanks to a designated station that then pushes that waste to the digesters. Hyperion needs 13 to maintain normal operations, but as of Thursday, only nine were working, the log shows.
Still, the plant has been repaired enough to operate “sufficiently,” Dafeta said.
But two overriding concerns remain.
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