Most people mindlessly start their morning by brushing their teeth, washing their faces, and flushing the toilet, which might seem like simple routine tasks. But beneath the surface, there’s a complex system that not everybody knows about.

Under city streets and parks lies a process that transforms wastewater into clean and usable resources. Meanwhile, desalination facilities are turning salty seas into freshwater sources along coastlines.

People pay little attention to the water they are using; they consume it without a second thought. Bay Area residents are fortunate to have a reliable water source from the Sierra Nevada snowmelt.

However, a recent drought in California has brought people’s attention to the fragility of traditional drinking water sources.

Alternative water sources may be crucial in future drought years and locations with unreliable or insufficient water supplies.

Two innovative options are recycled wastewater and ocean water.

The Bay Area already has multiple facilities recycling wastewater for industrial and irrigation use.

The East Bay Municipal Utility District (EBMUD), for example, has plants with the capacity to recycle 2.5 million gallons of wastewater per day (mgd), according to Zoe Lake, a Wastewater Control Representative at EBMUD.

Wastewater facilities use a three-step process to clean and disinfect incoming wastewater, creating safe, usable water.

These treatments remove enough contaminants for safe irrigation or industrial use. However, a fourth step must be added to the process for the water to be potable.

This fourth step involves disinfecting the water with ozone, filtering it through active carbon, clearing chemicals and salt with reverse osmosis, and using UV light for advanced oxidation.

EBMUD does not currently treat water to the potable stage, primarily due to the plentiful drinking water supply in the Bay Area, according to Lake.

While not directly producing drinking water, the recycled water produced by these facilities can be used in some applications as a substitute for potable water. This allows the potable water to be conserved for more essential purposes, such as drinking and other household uses.

Currently, one of the primary barriers to increased recycled water usage is infrastructure. 

“We’re working to match the need to what we produce. To plan for the infrastructure to make that so means adding pipelines to be able to treat and deliver that water,” said Andrea Pook, a spokesperson for EBMUD.

While the EBMUD plants have a capacity of 2.5 mgd, the typical daily production is less than that because of the lack of demand.

“We want to be able to match what people want, but people don’t want it yet, and they’re not ready to take it yet,” Lake said.

As the Bay Area population grows, this demand may change, but for now, the current EBMUD facilities meet the recycled water needs of their residents.

For the majority of the residents living in South San Jose, Valley Water uses the Santa Teresa Water Treatment Plant to provide safe drinking water in a unique way. 

Most of the water comes from the San Luis Reservoir. Using 30 of the 50 available acres, the facilities first start processing the water by adding alum and chlorine to eliminate algae or other bacteria in the water. 

“There’s a bunch of impellers built into the big pipeline to help ensure that the chemicals get mixed into the water properly,” said Lotina Nishijima, a water treatment operations manager at Valley Water. “The dirty particles clump together and go through more pipelines to get into the flocculation sedimentation basins.”

A bit more polymer is then added to help add weight to the particles and allow them to settle.

Similarly to EBMUD, ozone contractors are used to further clean the water. Ozone helps counteract the byproducts that come along with the use of chlorine in the first stage. Then, the water travels through different filters on site.

“We have 12 filters, which is great because that gives us a lot of flexibility if we have to work on one filter. Our filters are made up of 10 inches of sand and 48 inches of granular activated carbon,” Nishijima said. 

After a few more stages of adding various chemicals to ensure cleanliness, the water is ready for drinking. 

Unlike most wastewater treatment plants, the Santa Teresa Water Treatment plant sells the treated water to retailers, who then sell it to people for daily use. 

“The majority of it goes to our local water company called San Jose Water Company; they’re considered the middlemen. They’re the ones who interact directly with a lot of citizens.” Nishijima said. 

Valley Water operates 24 hours a day and delivers up to 100 million gallons of water daily, providing residents with a great alternative source of clean water.  

Sewage that originated from households and businesses around the Bay Area travels to the San Mateo wastewater facility. The water undergoes treatment to help keep the San Francisco Bay safe and clean. 

San Mateo uses an activated sludge system, a process in which oxygen gets added to the wastewater. 

“Our technology is over 100 years old, but it is one of the most consistent and reliable treatment processes you will find in wastewater,” said Robert Knox, an Operations Superintendent for San Mateo. 

When the wastewater originally comes, it undergoes a physical treatment called primary clarification. Then, the water’s flow rate slows down, allowing the heavy solids to separate from the liquid waste stream. 

“Those solids are then pumped to our solid treatment process, and then it’s the clarified effluent from primary clarification that goes to the activated sludge process,” Knox said. 

After, the solid stream travels to a gravity thickener, which prepares it into solid waste to be later broken down. During this process, methane gas leaks, and San Mateo is looking into new technologies to capture that gas and create renewable energy with it. 

The city of San Mateo is also looking into new technologies and processes to develop a recycled water program. 

“It’s very early on. We are looking at a number of options to create recycled water, and I think indirect potable reuse is what we’re looking at currently,” Knox said.

Indirect potable reuse is a process that treats the wastewater and later reintroduces it to natural systems, like reservoirs. The water undergoes further filtration before entering another round of treatment to make it safe for drinking. 

For most of the students at Carlmont, the water being used is treated by this local wastewater plant. San Mateo ensures that the community’s water is properly treated and returns to the environment safely. 

With 97% of Earth’s water stored in the oceans, it may seem like a no-brainer to look to the seas in times of drought.

Large desalination projects have already been implemented in various regions worldwide, namely The Claude “Bud” Lewis Carlsbad Desalination Plant in Southern California and the Sorek Desalination Plant in Israel.

Northern California is starting to dip its toes in the ocean with California American (Cal Am) Water’s desalination project in Monterey Bay.

The project is still in its permitting phase; the only construction so far has been the installation of test wells on the proposed site, according to Josh Stratton, the Manager of External Affairs at Cal Am.

The traditional method of water intake for a desalination plant is to install an intake pipe in the ocean. These pipes can harm wildlife and aquatic ecosystems, so the Monterey plant will use slant wells buried beneath the beach to avoid contact with animals.

“When people think of desalination, they think there’s a big pipe that goes in the ocean and just sucks water straight from the ocean, but our project is a slant well,” Stratton said. “The reason that’s so important is that it doesn’t affect sea life at all.”

The California Coastal Commission approved the project on Nov. 17, 2022, but they gave Cal Am 20 conditions that must be met before plant construction begins.

According to Stratton, one of the conditions CalAm focuses on is the required renovations to the outfall pipe. When fresh water is extracted in the desalination process, a salty brine called effluent is left over and must be pumped back into the ocean.

Cal Am planned to use an existing effluent pipe a short way away from the plant. Still, the Commission decided the pipe must be longer and have more outlets to disperse the effluent better, avoiding a concentrated discharge in one area.

According to Stratton, the community’s response has been a mixed bag.

“There has been a moratorium on new building and on new water meters, so a lot of people are scared that if we have a new, reliable water source that will enable more building,” Stratton said.

Despite some local concerns about the project, Stratton projects the plant will be ready for operation in 2028 and urges its importance in providing Monterey with a reliable water source.

“We’re just the water company; our job is simply to provide reliable water for the community, and we won’t be able to do that unless we have desalination,” Stratton said.