California is dry from the worst drought in history, so the state’s water managers are searching for answers. One solution they say is to reuse treated sewer water, but experts fear that the public may not be ready for drinking their water from “toilet-to-tap.”
The filtering technology for the system is already being tested by two Northern California water districts. In Southern California, Orange County is recycling 100 million gallons of waste water a day, treating it and returning it to aquifers, according to the San Francisco Chronicle.
Home grey water systems already reuse some household water, from dishwashing, bathtubs, and sinks for gardening or toilet water. But municipal systems would purify sewage on an industrial scale, returning filtered water back to the consumer as potable water.
The systems work by filtering sewage through several stages. Solids are removed, and the water is treated to the point where it is considered safe for ocean discharge. Then microfiltration and a reverse osmosis process eliminate concerns from bacteria or other pathogens. Finally the water is treated with ultraviolet light and hydrogen peroxide, rendering it equivalent to distilled water.
But public perception may be a challenging barrier to overcome. A $24.5 million system built in San Ramon, California in the 1990’s was rejected when local residents found out the original source of the “filtered” water.