An Inside Look at the City’s Southeast Water Treatment Facility

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Located on Phelps Avenue in Bayview Hunter’s Point, the Southeast Treatment Plant is one of two facilities that process water for the city of San Francisco. Built in 1952, this plant treats the majority – 80% – of the city’s wastewater flow.

Wastewater is defined as a combination of street runoff and the water that is flushed down toilets and drains. This water is contaminated by a variety of litter, debris, micro-organisms, and other hazardous content that must be processed out of the water supply.

When wastewater from all sources makes its way into the City’s sewers, its first stop is one of many underground storage/transport boxes that are placed around the circumference of the City. In these boxes, the first round of processing occurs, not as a result of human engineering but as a function of the chemical content of the materials in the water. Any minerals and other solid sediments in the water sink to the bottom of the boxes, and oils rise to the top. The oils are then skimmed off the top, and the sediments remain in place at the bottom of the boxes. The wastewater – cleaned of some hazardous materials – is then sent to either the Southeast Treatment Plant or to the City’s other processing facility, located on Great Highway near Ocean Beach and the Zoo. The primary purpose of these two facilities is to disinfect water that has already been cleaned of solid content and of oils.

California’s current drought conditions complicate the wastewater treatment process. As households and businesses conserve water, less water enters the city’s sewers, yet the quantity of solids entering the sewers due to road runoff, human and animal waste, and industrial byproducts, remains relatively consistent. As a result of the higher ratio of solids to water, the bottoms of the boxes develop layers of sediment quickly and must be cleaned often. This cleaning process includes pumping the sludge from the bottoms of the boxes into machines called digesters, where they are heated to at least 95 degrees Fahrenheit and slowly broken down by anaerobic bacteria for about 15 days. The end result of this process – a substance known as “biosolids” – is a nutrient-rich organic material that is non-hazardous and non-toxic, and used for agricultural fertilizer. In addition, this process produces methane gas, which is then recycled and used to provide 1/3 of the plant’s electrical power needs.

Similarly, the upcoming El Niño winter will bring its own set of challenges to the City’s Public Utilities Commission. While the treatment plant currently processes about 60 million gallons of water per day, it is able to process up to 250 million gallons per day. When it is especially wet, the total wastewater entering the treatment boxes can exceed the plant’s maximum capacity, which then calls for excess water storage. The City also has the option of activating a third processing plant known as the North Point Wet Weather Facility. Located on Bay Street and the Embarcadero, this plant becomes operational when the City’s daily wastewater accumulation exceeds 250 million gallons per day.

San Francisco is known for its high-quality tap water, and the staff at the Southeast Treatment facility and in the City’s Public Utilities Commission work to maintain this high standard, largely by closely monitoring the water’s mineral content. In 2005, the Southeast Metals Lab was recognized as one of the best in the world by Canada’s National Research Council.

Kenneth Olivencia, a Management Assistant at the Southeast Treatment Facility, who also oversees health and safety at the plant, explained that the plant has two key points in its mission statement. First, the mission of the plant is to protect the health and safety of everyone who uses the City’s water supply. “We treat every single drop of water that comes out of pipes into people’s homes and businesses,” Olivencia said. In addition to possible dangers from improperly treated water, the City is also aware that water treatment plants pose a potential homeland security threat, and Olivencia asserts that every employee at the plant is committed to the absolute security and integrity of the plant. Of equal importance is the facility’s mission to protect the environment. Olivencia believes strongly that most citizens would be awed to know about the intricate, environmentally sound, and deeply important work done at the plant.

In addition to his role as Management Assistant at the Southeast Treatment Facility, Olivencia is also the in-house chef. He recently cooked a Thanksgiving meal for the entire staff to eat together – employees in business casual and orange safety vests alike. “We’re like a big family down here,” Olivencia said. “We really are.”

The plant offers monthly tours of the facility, which are free to all citizens.