Expert could help turn odor around
Engineer Michael Stenstrom will try to identify other smelly compounds coming from the El Segundo facility
El Segundo has hired an environmental expert to create a better line of communication between the city and a nearby wastewater treatment facility, and urge officials at the Los Angeles-run facility to make odor-mitigating equipment fixes as soon possible.
Michael Stenstrom, a UCLA civil and environmental engineering professor who has worked on more than 200 wastewater treatment plants since 1977, will work with El Segundo on all issues related to the Hyperion Water Reclamation Plant, City Manager Darrell George announced during this week's City Council meeting.
Hyperion experienced a backup in July 2021 that flooded the facility, forcing officials to send millions of gallons of untreated sewage into the ocean to prevent the plant from going entirely offline. It took weeks to get the plant back to full operations, during which overwhelming odors plagued residents.
Though most of the stench has dissipated, residents have said a lingering odor from hydrogen sulfide remains, prompting criticism from El Segundo officials, the regional air pollution watchdog and others.
Los Angeles Sanitation & Environment, which oversees the plant, has made some changes to get rid of the smell and continues to make more improvements. And Hyperion is set to fix all of the affected equipment by the end of next year, officials there said, and the plant hasn't had any violations from the South Coast Air Quality Management District since the beginning of the year.
But El Segundo residents have continued saying they need more support to get things cleared up.
That's where Stenstrom comes in. The professor will work to figure out exactly what chemicals and particulate matter may be floating around the city from Hyperion.
“We've taken this extraordinary step of retaining our own expert because, frankly, the people in this town no longer trust what Hyperion has been telling us,” Councilmember Ryan Baldino said during the panel's Tuesday meeting. “We've been living through this for years now and we look forward to using (Stenstrom's) expertise and knowledge to help explain what's going on and set a clear path forward.”
Stenstrom, too, said he is eager to get relief for the city.
“I'm anxious to help El Segundo resolve their issues with Hyperion,” he said during the council meeting, “and improve their overall performance in reducing odors and other problematic things, as well as helping them into the future.”
Stenstrom is an expert in process development for wastewater treatment systems and stormwater management, according to UCLA's website. He also authored a report, with the Los Angeles Public Works advisory committee, that was published last year and blamed the 2021 Hyperion sewage spill on a combination of human and technological mistakes.
L.A. sanitation officials said they also look forward to making things better.
“We welcome the opportunity to work with Michael Stenstrom on progress and upgrades at Hyperion, and we remain committed to improving our efforts to better inform and communicate our work at the facility,” Elena Stern, spokesperson for L.A. Public Works said by email Friday.
Stenstrom has been working with El Segundo for a few weeks now, George said, and has set up an initial meeting between the city and Hyperion's executive director and staff for March 22.
The unpleasant-smelling hydrogen sulfide isn't the only emission that could be in the air, Stenstrom said, and one of his goals is to get Hyperion to test for other potential compounds, and then have the plant adopt treatment strategies to remove them.
“Once you eliminate hydrogen sulfide, which the Hyperion plant is designed to do,” the professor said, “you can have other odors that aren't so pungent initially, but have longer term effects.”
The recommendations Stenstrom made with the advisory committee were intended to prevent another spill from happening at Hyperion, develop better notification methods and make infrastructure improvements, such as contouring the road differently so that potential spills don't fall into the electrical headworks.
What he's suggesting now, Stenstrom said, are future improvements for odor control.
AQMD, meanwhile, has an abatement order in place requiring Hyperion is to make changes at the facility that will fix the odor and prevent major spills in the future.
Hyperion is estimated to complete all of its equipment refurbishment as early as April, according to a February report from the plant, and with all other work to be done by December 2024.
Some of that work is happening right now.
On Tuesday, Hyperion began a 10-day process of taking measurements to replace the current primary tank covers with new ones, George said.
The current ones are old and corroded, and AQMD staff previously identified those tanks to be the main source of hydrogen sulfide odors.
During the measurement work, from 7 a.m. to 4 p.m. on weekdays, George said, the old covers will be lifted up — which may release some odor into the neighborhoods.
AQMD also told El Segundo that complaints about Hyperion in the past two weeks have been relatively low.