...this week, for millions of people here in Orange County, pulling the lever will be the start of a long, intense process to purify the sewage into drinking water - after a hard scrubbing with filters, screens, chemicals and ultraviolet light and the passage of time underground.
On Friday, the Orange County Water District will turn on what industry experts say is the world's largest plant devoted to purifying sewer water to increase drinking water supplies. They and others hope it serves as a model for authorities worldwide facing persistent drought, predicted water shortages and projected growth.
The process, called by proponents "indirect potable water reuse" and "toilet to tap" by the wary, is getting a close look in several cities.
...."These types of projects you will see springing up all over the place where there are severe water shortages," said Michael Markus, the general manager of the Orange County district, whose plant, which will process 70 million gallons, or nearly 3 billion liters, a day, has already been visited by water managers from across the globe.
The finished product, which district managers say exceeds drinking water standards, will not flow directly into kitchen and bathroom taps; state regulations forbid that.
Instead it will be injected underground, with half of it helping to form a barrier against seawater intruding on groundwater sources and the other half gradually filtering into aquifers that supply 2.3 million people, about three-quarters of the county. The recycling project will produce much more potable water and at a higher quality than did the mid-1970s-era plant it replaces.
The Groundwater Replenishment System, as the $481 million plant here is known, is a labyrinth of tubing and tanks that sucks in treated sewer water the color of dark beer from a sanitation plant next door and runs it through microfilters to remove solids. The water then undergoes reverse osmosis, forcing it through thin, porous membranes at high pressure, before it is further cleansed with peroxide and ultraviolet light to break down any remaining pharmaceuticals and carcinogens.
The result, Markus said, "is as pure as distilled water" and about the same cost as buying water from wholesalers.