Global environmental challenges
Overcoming the ‘ick’ factor of wastewater recycling
After an hourlong tour of the world’s largest wastewater recycling plant, where 70 milion gallons of pre-treated sewer discharge is distilled daily to help replenish the underground drinking supply of Orange County, California, I was led to a sink with a faucet. There I was presented with a plastic cup and invited to take a sip.
Crystal clear and utterly tasteless, the sample was refreshing and perfectly safe for human consumption. Some minerals are actually reintroduced to the water before it’s pumped back out of the ground for general consumer use.
Michael Markus, general manager of the Orange County Water District and the chief engineer behind the plant, assured me that the water exceeds all government drinking standards, even though the state requires the county to put it into the local aquifer — for additional natural filtration — before offering it to the public.
NASA has recently developed a new system for purifying urine and other wastewater for astronauts to drink in space. But this is wastewater recycling for the masses.
The technology has been available for years but was long disparaged by cynics in the media and politics as “toilet-to-tap.”
Now with drought-related water shortages expected to worsen from climate change, even as cities continue to grow, the scarcity and escalating price of fresh surface water has made recycling more economically viable and helped it overcome the “yuck” factor.
The year-old, $481 million Orange County facility, called the Groundwater Replenishment System, produces enough purified water to meet the drinking needs of 500,000 people and is serving as a model for numerous cities across California looking to augment their own aquifer supplies.
Several smaller plants exist around the world, including one in the southern African country of Namibia, where purified wastewater is added directly into the public drinking supply, without first percolating through an aquifer or settling in a reservoir. In the parlance of the industry, that’s called “direct potable reuse.”
Photo credit: Reuters/Steve Gorman (Michael Markus, general manager of the Orange County Water District, stands near a microfiltration unit in February 2009).