The Poop Parade: Behind The Scenes of the Oceanside Treatment Plant

The primary clarifier in the Oceanside Treatment Plant

“That there? That’s raw sewage,” our tour guide Jonathan pointed out, with obvious glee. “Get a good look at it, but be careful that none of it splashes on you.”

I was standing in the bowels of the Oceanside Water Pollution Control Plant, with about 12 other brave visitors, on a tour of the inner workings of one of San Francisco’s two primary sewage-treatment facilities. The raw sewage flowed through a small sink, part of an observation station where chemists could monitor the pH of the waste, the level of toxins — fun stuff like that.

“Alright, let’s keep moving. Gotta go to the clarifiers next,” Jonathan said with a flourish, and we were off, continuing a recent public tour of the plant.

As an Ocean Beach resident, surfer and writer for the Ocean Beach Bulletin, I was curious to get a behind-the-scenes look at the facility. It looms, imposing and mysterious, on our coastline, tucked behind large cement walls along the southern edge of the Great Highway. I knew almost nothing at the beginning of the tour, beyond the fact that in 2008 there was a citywide ballot initiative to change the facility’s name to “honor” outgoing President George W. Bush.

Our guide for the day was Jonathan Smith, a tour coordinator at the plant, which is operated by the San Francisco Public Utilities Commission. We convened in a bright conference center, went through some of the predictable introductions, and then Jonathan put on a surprisingly engaging documentary that explained San Francisco’s sewage system. And the learning began.


The San Francisco sewage system stands alone in the state of California in that that it deals with the combined sewage of human waste and road runoff. The process of filtering all of that waste out of the water, and turning the end product into something that is not harmful for the bay or the ocean, is very complicated. So complicated that the steps were repeated to us over and over again, at least a half a dozen times throughout the tour, and yet there were still questions about it. A lot of questions.

The Oceanside Treatment Plant handles about 20 percent of San Francisco’s waste water, with the other 80 percent going to the Southeast Treatment Plant in the Bayview. Under the city streets is a complex network of more than 1,000 miles of sewage pipes. During the dry season, San Francisco residents generate 83 million gallons of waster water a day, which the documentary explained is enough to fill 120 Olympic-sized swimming pools. Pretty incredible.

So the Oceanside Treatment Plant has to handle 20 percent of all that water, which in the dry season means about 20 million gallons per day, and in the rainy season, up to 65 million gallons per day. There is an overflow station, the North Point Wet Weather Facility, for times when the system floods due to too much water.

Waste water arrives to the plant via large storage drains under the Great Highway. It gathers at the Westside Pump Station, which is at the corner of Sloat Boulevard and the Great Highway, and from there is pumped into the treatment plant.

There are four steps involved in getting rid of all the stuff that is in waste water:

  • First, the water is pretreated and drained through large screens that get rid of objects such as gravel, rags and sticks.
  • The water then goes on to the primary clarifiers. Here, the water is allowed to be still, and gravity sorts the scum (objects that float) from the sludge (objects that sink). Skimmers get rid of both the scum and the sludge.
  • The water then goes into large storage tanks for aeration, where it is treated by bacteria and other microbes to decompose the organic material. Pure oxygen is pumped into the tanks to constantly stimulate the the microbes to keep eating.
  • The last step is in the secondary clarifier, which performs the same function as the primary clarifier.

A graphic organizor that explains the process of water treatment at the plant.

After the secondary clarifier, the end product, called effluent, is pumped about 4.5 miles into the ocean, and dumped into the sea. According to the literature provided at the pre-tour meeting, “high salt concentrations and cold temperatures help to kill any remaining bacteria.”

I asked Maurice Hayes, a shift manager who joined us on the tour to explain some of the more technical components of the facility, if the effluent was potable.

“No, no, no. Not potable at all,” he quickly answered. “But I’ve heard of a plant in Saudi Arabia that goes through a tertiary clarifier, and they end up with potable water. But that technology is extremely expensive.”

He paused wistfully for a moment. “But we might see that here in San Francisco in our lifetimes. Drinkable water coming out of a treatment plant. What a thought.”


A tour of the Oceanside plant requires some preparation. In an email the SFPUC sent out before the tour, participants were told to wear closed-toed shoes and long pants. We were given hard hats and rubber gloves on the way out of the conference room. We were told to roll up the legs of our pants. If there was a railing, we were told not to lean against it. We were going into the heart of the western half of the city’s waste, and were dressed to come out as unscathed as possible.

The plant was built in 1993, and more than 70 percent of it is underground, under the San Francisco Zoo. So you can’t see most of the facility. Just large, looming entryways. We entered a tunnel entrance, went down a few sets of stairs and were inside.

The most immediate sensation from the tour was the smell. It smelled like the excrement of a modern city, which is exactly what it was. The stench was potent and painful. You not only smelled it, but you tasted it in your mouth, and felt it soaking into your clothes. For the first time in my life, I found myself grateful for having chronic sinus problems.

Our tour guide Jonathan Smith

Jonathan wore a bright green vest and carried a flashlight that looked like he had ripped it off the hood of a 1920s car. The tour visitors huddled together, afraid to get left behind in the dizzyingly complex network of rooms, hallways and tunnels. We walked through areas of patchy lighting, convened in dense tunnel networks suffocating under the countless pipes that lined the ceiling and walls, and wandered through large, open expanses. The constant roar of the plant machinery meant that shouting was necessary for conversation to be heard.

It’s not surprising to report that a sewage facility is not exactly photogenic. It is exactly how you might imagine it to be: large, concrete, damp, dark, and full of steel pipes and guys in jumpsuits. Its design is strictly utilitarian, and all aesthetics clearly have been brushed aside in favor of a massive structure that does its job.

The grossest part of the tour, by far, was the hall of the primary clarifiers. The room was huge, about the size of eight basketball courts, and was full of more than a dozen pools, each one about 25 yards long and 10 yards wide. Skimmers slowly dragged along the surface of the water, catching as much scum as possible, ferrying it all toward one side of the room. We walked over and looked down on what looked like clumps of floating feces. Unlike many of the other visitors, I hadn’t thought to bring a handkerchief with me to cover my nose, and my eyes stung with the smell.

Each pool was equipped with a lifesaving flotation device — you know, just in case someone fell in.

“I’ve been here for a long time, and I’ve never seen them used,” Maurice reassured me. “They are just a safety feature.” Still pretty horrifying to think about.


We paused for a long question-and-answer period in a monitoring station, where two computer monitors flashed a vibrant digital map of the facility. The map’s constantly changing data display looked a bit like an old Pacman game, with 80s-era neon lights and . “This station tells us if there’s a problem with the system,” Jonathon proudly explained.

“How often do the alarms sound with problems?” one of the visitors asked.

“All the time,” Maurice sighed wearily. “It can be really quiet, but it can be really, really busy here, where all we do is run around, re-booting systems that have crashed or fixing leaks.”

“Is this facility retrofitted for earthquakes?” someone else shouted out over the din.

“Great question. We were designed to handle up to an 8.6-magnitude earthquake.”

I remembered that the earthquake that hit Japan was a 9.0.

“What about any resulting tsunamis?” the same person asked.

“Tsunamis … .” Maurice trailed off.

“Tsunamis … .” Jonathon tried to resume his line of thinking, but he also had nothing to say.

We were underground, so we didn’t have a view of the ocean. But if we went straight up from our underground location, the high-tide line was probably only a few hundred feet from the room.

“Let’s just say that it’s kind of scary to think about tsunamis,” Maurice finally said, a bit hesitatingly.

“You know, because of what happened in Japan,” the visitor kept insisting.

“Oh, we know about what happened in Japan,” said Maurice. He didn’t have much else to say in terms of reassurance.

The mood changed fairly quickly as we all shuffled back out of the station to explore more of the building and to replace our worries about tsunamis with worries about the powerful stench.

“Does the smell bother you?” someone asked.

“Nah,” Maurice grinned. “I’m used to this shit.” We all laughed.


I had my doubts when I heard that the Oceanside plant’s effluent was released into the ocean, via a 4.5-mile pipe, after being sorted through the secondary clarifiers. It seemed like the water would still be filthy. But we went to the room of the secondary clarifiers, where the last step of the water treatment happens. The smell was less noticeable but still very present. But lo and behold, the effluent was pretty damn clear.

“EPA standards insist that we remove 80 percent of the solid waste from water before we dump the byproduct anywhere,” a plant scientist — whose name I missed — had explained to us back in the offices. “Here at Oceanside, we remove between 96 percent and 97 percent of all waste. We’re quite proud of that.”

“In fact, in 2004 we were recognized by the EPA as the best facility in the whole United States,” he added, his stance wide and his arms crossed in a celebratory pose.

After the second clarifier, the tour wrapped up a bit anticlimactically. We went by a locker room, and the next thing we knew we were back in the lobby of the administrative building where we had started. Everyone scattered, eager to get back to their un-smelly lives. There wasn’t a send-off message, no conclusive “So that’s why you should be careful about what you flush down the drains,” or “Try to reduce water consumption,” as I had been expecting.

When you have the better part of a million people living in a small city, you’re going to have to deal with their waste somehow. At the Oceanside Water Pollution Control Plant, the solution has been buried out of sight, with the fumes and murky pools hidden from view of the surrounding neighbors.

It’s almost unnoticeable, which is exactly how it was designed to be. No one wants to have to wade through the city’s waste. And so most don’t. We’re content with vague awareness that a team of engineers, scientists and laborers is working around the clock to keep our sewage out of the bay and out of the ocean. But for two and a half hours, the reality of that work was shoved into my face and into my nostrils.

I was impressed with how proud of their work these men and women clearly were. They knew that they perform a vital task in the functionality of the city. Without them, and without this plant, we would be up to our eyeballs in our own waste.

Most of all — and this was, by far, the impression I expected the least — I felt bizarrely connected to my neighbors. That was all of our waste in there, all of it being wiped squeaky clean, together.

What a strange way to feel close to strangers, I thought to myself as I sped off, windows down, gulping in the fresh scent of the ocean air.

EDITOR’S NOTE: The City offers monthly public tours of the Oceanside plant, and can arrange group tours and school field trips. Participants must be at least 10 years old.

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  1. A correction to ED’s comment:
    The effluence from the Oceanside waste water treatment plant does not going through a chlorination process to kill bacteria (disinfect), hence, no de-chlorination process in place at Oceanside plant neither. The purpose of the treatment there is to remove as much solids and nutrients as possible from the raw sewer.
    Answer to tim newhoff
    The solids are hauled to farms north and east of SF to use as fertilizer. It is free to the farmers to use. City of SF pay a contractor to haul the solids away.

  2. An important step not mentioned here is that the effluent is treated with lots of bleach to kill off microorganisms. Then it is dechlorinated so the chlorine won’t hurt marine life. THEN it goes to the ocean.

    And tertiary treatment can take many forms, including nature’s (a wetland).

    Also, you may not know that GG park actually used to have a treatment plant. Another one could be tucked away there just like Oceanside is.

    So before we get our NIMBY walls up, let’s remember that we are all responsible for our waste, and these plants have to be located SOMEWHERE. Let’s come together to figure out the best solution for all of SF.

  3. excellent article.

    ? where are all the solids hauled to??

  4. Thank you for this informative and interesting article. Regarding the quote about someday drinking treated sewage water, there are now plans to build a tertiary water treatment plant in San Francisco. It will be used for irrigation right now, but the water will enter the aquifer under the City and eventually go full cycle to become part of our drinking water. See the SFPUC websites on the Westside Water Treatment Plant and the Groundwater Plan for more information.
    Currently the SFPUC is considering various locations for the tertiary treatment plant, including one in Golden Gate Park. We don’t think that Golden Gate Park is an appropriate location for a factory and are working with the SFPUC to locate it elsewhere. But we need the public to also weigh in and ask the SFPUC and our representatives to preserve Golden Gate Park as parkland. Please go to our website for more information:

    Katherine Howard, member
    Steering Committee
    Golden Gate Park Preservation Alliance

  5. Great article and an interesting behind the scenes look at something that the vast majority of people never think about. Glad that OBB could smell out this story.


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