December 10, 2012
by Tom Fudge
Up to 200 million gallons of San Diego water comes to the Point Loma treatment plant every day, to be treated and pumped into the Ocean. But people are starting to imagine another way to handle our wastewater.
Marsi Steirer holds up a beaker of very clean-looking water at the North City Water Reclamation Plant. She is director of an experimental project for the City of San Diego that purifies the water that has gone down the toilet and down the drain. She said the end product is, if anything, more pure than your tap water.
The idea of turning San Diego’s sewage into drinking water will hit another milepost next year. That’s when we’ll see a final report on the test project Steirer manages. After that, it’ll be up to the mayor and the city council to decide how to proceed.
The whole point of the test project is to find a way to turn wastewater into a large, reliable source of potable water for San Diego. Steirer points out the cost of imported water for San Diego has risen 85 percent in the past 8 years, and the prices aren’t headed anywhere but up.
“It’s estimated that the cost of imported water will double by 2020,” she said.
So is it cheaper to recycle water than to import it? Not yet. In fact, locally produced recycled water would, today, still cost nearly twice as much as imported water. But Steirer suggests that within 10 years those costs could be about the same
In San Diego’s recycling pilot plant, water is forced through very fine filters in the process called “reverse osmosis.” Any remaining contaminants in the water are then blasted with UV light, and mixed with hydrogen peroxide.
In fact, this process is already used to create clean water at the Orange County Water District.
“This plant produces 70 million gallons per day,” said Mike Markus, the General Manager of the Orange County district, as he stood outside a facility called the Groundwater Replenishment System. He said Orange County’s recycling system produces enough water to serve 600,000 people.
“And this project is the largest planned indirect potable reuse project in the world,” he added.
“Indirect potable reuse” is industry jargon for wastewater recycling. It’s indirect because Orange County purifies the water, then they pump it into a groundwater aquifer where it mixes with the rest of the local water supply. Markus said recycled water gives his customers some water dependability.
“In most of Southern California, as I’m sure you’re well aware, we’re reliant on outside sources… imported water,” said Markus. “Really about 70 percent of (Orange County’s) water supply portfolio is variable in nature. So we have to come up with something where we have that reliable source of water, and that’s what recycled water gives us.”
Meanwhile, San Diego faces another issue that makes water recycling crucial. The city still has a waiver that lets it dump sewage into the ocean at a treatment level that’s below EPA standards. But that waiver won’t last forever, and upgrading the Point Loma treatment plant to meet standards would cost more than a billion dollars.
So what if San Diego could dramatically reduce the flow to Point Loma by recycling water upstream?
Attorney and environmentalist Marco Gonzalez has spent many years negotiating with the city over water treatment strategies. He said it makes more sense to focus on recycling water than on upgrading the Point Loma plant, at huge expense to ratepayers.
“We realized that we have this untapped resource in all of this sewage, and all of this water that we’re basically wasting by dumping it into the ocean,” he said. “So we approached the city with the novel concept of not opposing the waiver.”
In return for that, he said, the city would look for a way to recycle water, with the lofty goal of no longer having to discharge treated sewage into the ocean.
But there’s one more issue with wastewater recycling: The yuck factor. Opponents of recycling in San Diego have succeeded in stalling it by branding it “toilet to tap.” But Marsi Steirer said surveys by the city show attitudes are changing, with 70 percent of residents supporting the idea.
Steirer is clearly irked by the expression toilet to tap, which she said is simply not true.
“It’s obviously not toilet to tap,” she said. “You saw on the tour that there are multiple treatment steps that are involved. So it’s inaccurate, but I’m sure a lot of people think it’s cute.”
In Orange County you can take the ultimate test of whether recycling wastewater actually works. I drank some newly recycled wastewater, and it tasted, well, like water.