How would you like to drink water so clean and clear that it practically sparkles with the brilliance of a well-cut diamond? What if that water was from a sewer? Would you drink it then? The scientists over at the Advanced Water Purification Facility (AWPF) are hoping you will. An article on the subject by ScientificAmerican.com says:
“Tests have shown that purified sewage from residential buildings is not only cleaner than existing drinking water, it can be produced at less cost than other options for creating freshwater, such as desalination.”
As a consequence of the recent droughts afflicting the American West, water shortages have become a serious problem. San Diego, California is one of the places most impacted. From the article:
“San Diego imports as much as 90 percent of its water from the Colorado River to the east and the Sacramento–San Joaquin River Delta to the north. But both those sources are running dry. The price of imported water will double in the next decade. By converting effluent [sewage], San Diego could meet 40 percent of its daily water demands. And it would put an end to the city dumping poorly treated wastewater into the ocean.”
But as the article indicates, the main problem with using purified sewage water for drinking isn’t that it’s dirty- it’s that people can’t get over the idea that it’s dirty. It’s the “yuck factor,” as it is cleverly called by the author.
The goal is eventually for the system to be used all over the country, but right now it’s only used for irrigation until government officials, and residents, feel certain that the water is safe to drink.
So how can people be assured of this water’s safety? Upon reading how rigorously the water is filtered and tested, I must admit I’d give it a try. Here’s more details about the filtering process from the article:
“Traditional treatment for U.S. drinking water goes through two or three steps for removing suspended solids and is then disinfected using chlorine. Transforming fragrant sewage into pristine tap water requires different engineering. The AWPF plant takes sewage water treated by the North City Water Reclamation Plant and adds higher levels of cleansing to ‘purify’ it.”
“The first step at the AWPF is microfiltration, which happens in large tubes that resemble giant drums of pasta. Each drum contains 9,000 of these pastalike fibers and that each fiber is dotted with microscopic pores 300 times as narrow as a human hair. As water is forced through the tubes, the fibers filter out viruses, bacteria, protozoa and suspended solids.”
“Next, the water is sent at high pressure through tubes with even smaller fibers, in a process known as reverse osmosis. This step removes any remaining dissolved particles, up to 10,000 times as small as even the tiniest bacteria, including chemicals, viruses and pharmaceuticals. For the final step, water at the AWPF goes to advanced oxidation, where it is mixed in huge vats with minute amounts of highly concentrated hydrogen peroxide and then exposed to ultraviolet light. This stage destroys any remnant contaminants, even at quantities of parts per trillion, a dose equivalent to a single drop in hundreds of Olympic swimming pools.”
In addition to these steps, the scientists are planning to add still more, including exposing the water to ozone, making the resulting water far exceed legal drinking standards. In fact, water that goes through the first steps mentioned is already cleaner than today’s tap water. The creators of this process say they’d like to see this water replace current tap water in the future.
Water that is not only clean but cheap would be advantageous to everyone, especially those who will be hardest hit (and already are) by rising water costs. The rich can afford Evian. But what will happen to the rest of us?