A few times per year, East Bay Municipal Utility District allows curious residents to come take a look at what happens to everything that we flush down our toilets. The tours begin with a note of irony. Before a two-hour stroll through the wastewater treatment plant, visitors are advised to use the restroom at the front office, because there aren’t any lavatories within the bowels of this huge compound, which processes an average of 50 million gallons of raw sewage per day. Tour attendees are also warned to expect “strong odors.”
According to EBMUD, “due to popular demand, these free [tour] tickets are usually all taken within minutes,” so I considered myself lucky to be gathered with about 25 other visitors in front of the treatment plant on a recent Saturday morning. The group was young, diverse and surprisingly fashionable, like we could’ve been gathered to attend an underground poetry reading instead of a visit to “the poop factory,” as one of the other guests referred to it.
Entering the ‘poop factory’
Kicking off the tour, our guides Jennifer Ku and Eva Ng provided an overview of the operation. The plant treats residential, commercial and industrial wastewater from Alameda, Albany, Berkeley, El Cerrito, Emeryville, Kensington, Oakland, Piedmont and the Richmond Annex, serving about 740,000 people. This area has a separate sewer system for rainwater, which is allowed to flow into the bay untreated, so this plant was designed to process “anything that goes down the drain.” The facility’s sea-level location is crucial because gravity is the primary force that delivers waste from a sprawling labyrinth of underground pipes to the treatment plant.
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The East Bay Municipal Utility District wastewater treatment plant in Oakland, Calif., processes an average of 50 million gallons of raw sewage per day.
Courtesy of Liam O’Donoghue
Since plenty of unwanted solids end up in the sewage stream, the inflow process involves several layers of physical barriers that wastewater passes through during the cleansing process. As we made our way past a series of pipes, pools and structures bearing signs like “wet weather primary sludge thickeners,” the guides explained how soiled liquids get purified.
First, a layer of prison-style bars catches objects as large as two-by-fours. Then, a series of screens filter out smaller solids, including cash. I was informed that EBMUD employees are allowed to keep whatever treasures they rescue from the sieves, which conjures up a very different definition of “money laundering.” Mostly, the filters are catching feminine hygiene products and wipes, which we are informed several times throughout the tour, should not be flushed.
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“I know they claim to be flushable,” explained one of the guides, “but technically a diamond ring is flushable. You shouldn’t put that in the toilet, either.”
Deep inside the bowels
As the tour guides brought us deeper into the 69-acre complex, they shared the history of the facility, which is situated below the convergence of three highways approaching the Bay Bridge. Before the plant opened in 1952, raw sewage flowed directly into the San Francisco Bay, earning it the unappetizing nickname “the Big Stench.” Considering that motorists were known to use clothespins to clip their nostrils shut on particularly stinky days, it wasn’t a hard sell to convince East Bay voters to approve a $23,500,000 bond to fund the wastewater treatment plant’s construction.
The East Bay Municipal Utility District wastewater treatment plant in Oakland, Calif., processes an average of 50 million gallons of raw sewage per day.
Courtesy of Liam O’Donoghue
Although it’s unfortunate that eastbound cars approaching Oakland via the bridge are still often greeted with a whiff of “East Bay perfume,” the experience isn’t nearly as nauseating as it used to be. One person told me that he always gets a laugh out of his kids by saying, “Sorry, guys, Mom has gas again,” every time his family drives past “the poo plant.” Also, EBMUD doesn’t deserve sole blame for the stink, because some of the sulphurous odors come from biological emissions wafting up from the shoreline wetlands during low tide.
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As the tour approached a series of wide pools called clarifying basins, an unpleasant smell intensified, and I noticed that several of my fellow tour guests were passing around a small jar of Vicks VapoRub, which they were applying beneath their noses. Seeing this gave me flashbacks to the 1990s, when it was common to see JNCO-clad ravers slathering the menthol ointment all over their grinning faces to enhance the effects of MDMA. My hazy memories of all-night dance parties vanished as my attention was drawn to a series of hose-like faucets spraying mist into a trough of bubbly brown stuff that resembled a chocolate milkshake. I thought to myself that it would be a great joke to install a diving board on the edge of this vat. Swim at your own risk, indeed.
The East Bay Municipal Utility District wastewater treatment plant in Oakland, Calif., processes an average of 50 million gallons of raw sewage per day.
Courtesy of Liam O’Donoghue
Contact with the water wouldn’t be safe, but it has undergone significant improvement by this point in the process. Gritty sediments, like sand or coffee grounds, have already been allowed to settle out of the liquid, while “FOG” (fats, oils and greases) have been skimmed off the top. Pure oxygen has been pumped in to boost the ability of microorganisms to break down organic materials. The tour guides said that a healthy amount of bacteria needs to exist in these basins for the process to work, similar to how sourdough bread requires an active starter composed of fermented culture. When the treatment plant’s electricity was knocked out during 1989’s Loma Prieta earthquake, it took weeks for the bacteria to recover.
The great equalizer
Before we moved on to see the digesters, those large mushroom-shaped structures that are visible from the highway, the guides stopped to answer questions. I asked about the “Super Flush,” an urban legend that sewer systems are dangerously taxed by too many people using the toilet simultaneously during Super Bowl halftime shows, but neither of them were aware of that phenomenon. However, they did confirm that there’s an inflow spike on weekday mornings after hundreds of thousands of customers “take care of business” before going to work or school. Our society may be more fractured than ever, but it’s comforting to know that we’re still united by such timeless rituals as the morning dump.
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After passing through the clarifying basins, liquids and organic solids are channeled toward separate destinations. Biosolids are sent to decompose in heated digester tanks. Released methane is converted into electricity to power the plant, while some of the solids are turned into a product referred to as cake, but “not the kind you’d want to eat,” our guide quickly assured us. This cake is a kind of fertilizer that is used on feed crops like alfalfa growing in the Central Valley.
The East Bay Municipal Utility District wastewater treatment plant in Oakland, Calif., processes an average of 50 million gallons of raw sewage per day.
Courtesy of Liam O’Donoghue
Following tests to identify any hazardous chemicals that might be present, if the water is safe, it’s discharged though a long submerged pipe into San Francisco Bay. If operations have been running on schedule, it took this water six to eight hours to complete the treatment. However, a portion of the water is diverted into a recycling process that extends the purification cycle. This water is pumped through another series of microscopic filters and further disinfected. The recycled water isn’t potable, but is used for industrial purposes and for irrigating nearby landmarks, such as Pixar’s grassy campus, Mandela Parkway’s gardens, and Raimondi Park, home of the Oakland Ballers.
A 10 out of 10 experience
At the tour’s conclusion, guests are literally given the opportunity to stop and smell the roses. As our wonderful guides shared some final tips on avoiding clogged pipes (“when in doubt, throw it out”), I noticed a well-manicured collection of rose bushes next to the EBMUD office. After two hours of exposure to the aroma of fecal matter and chemicals, my nose was grateful for their gentle fragrance.
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My tour companion, the bestselling author Jenny Odell, had informed me earlier that this would be her fifth time visiting a wastewater treatment plant. I was curious to hear how EBMUD’s tour compared to an aficionado of sewage infrastructure. She didn’t hesitate before rating the experience 10 out of 10.
The East Bay Municipal Utility District wastewater treatment plant in Oakland, Calif., processes an average of 50 million gallons of raw sewage per day.
Courtesy of EBMUD
At the end of the tour, one of the guides gifted me a toilet bowl keychain. As I marvelled at the flippable toilet lid on this impressive bit of swag, I had to agree with Odell’s assessment. No wonder tickets for these tours always go fast. From now on, I’ll remember this morning fondly every time I flush.