Name: How Sewage Becomes Drinking Water
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Ongoing droughts are straining the supply of clean drinking water. One solution might lie in an unexpected source: wastewater. Through a method of purification called reverse osmosis, Orange County is making millions of gallons of dirty water drinkable again.

How do you make wastewater drinkable? It starts at the sewage treatment plant.

How Sewage Becomes Drinking Water

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Ongoing droughts are straining the supply of clean drinking water. One solution might lie in an unexpected source: wastewater. Through a method of purification called reverse osmosis, Orange County is making millions of gallons of dirty water drinkable again.

How do you make wastewater drinkable? It starts at the sewage treatment plant.

Tech & Engineering

How Sewage Becomes Drinking Water Published April 14, 2023Narrator: Moving water from areas of abundance to areas of scarcity was the kind of mega engineering that made the modern state of California possible. Over 1500 dams and about 4000 miles of canals had been rerouting water across the state for decades. But the population had exploded more than tripling since the 1950s. With the system nearing a breaking point. One thing was clear.Mehul Patel: The old engineering solutions of the past just weren't going to sustain us going forward.Narrator: So they focused on a source flowing right under their noses. 200 million gallons of wastewater literally going down the drain every day.But how do you turn the county's dirty water into something people can actually drink? It starts at the Orange County sewage treatment plant. Here, the largest solids are separated from the raw sewage and smaller particles are allowed to settle to the bottom of enormous tanks. Aerating the remaining wastewater provides oxygen to pollutants eating bacteria, which process the water to be clean enough to release into the environment for decades. That meant all of the treated water was pumped several miles out into the Pacific Ocean.Mehul Patel: Literally tens of millions of gallons a day just going out to the ocean, being lost, essentially.Narrator: Could those millions of gallons be the solution to Orange County's dwindling aquifer and also make their system essentially drought proof?Mehul Patel: We knew that people had done water recycling. They just hadn't done it to a point where that water could be really efficiently reintroduced into a groundwater basin. But we knew it was possible.Narrator: Today, Mehul’s plant finishes the job. It's a computer operated system of airtight tubes and underground pipes. At the heart of the operation is a process called reverse osmosis, where 1000 horsepower engines push the water through tightly wrapped membranes, filtering out impurities like pharmaceuticals, viruses, and salts.Mehul Patel: So this is the end of the process. We can see how the water started out. You could see everything that was removed and then you could see the purified water here that's safe enough to drink. But we'll still go through a couple more steps after this.

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How Sewage Becomes Drinking Water

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