One of the many strategies California has been planning to help manage its limited water resources is coming to fruition. After a decade of work, the draft plans for using highly purified sewage as drinking water are headed toward a round of public comment, hearings, and peer review expected to approve them.
Cleaner than spring water!
The new rules, mandated by state law, would require extensive treatment and monitoring before wastewater can be piped to taps or mingled with raw water upstream of a drinking water treatment plant.
"Toilet-to-tap" this is not.
Between flush and faucet, a slew of steps are designed to remove chemicals and pathogens that remain in sewage after it has already undergone traditional primary, secondary and sometimes tertiary treatment.
It is bubbled with ozone, chewed by bacteria, filtered through activated carbon, pushed at high pressures through reverse osmosis membranes multiple times, cleansed with an oxidizer like hydrogen peroxide and beamed with high-intensity UV light. Valuable minerals, such as calcium, that were filtered out are restored. And then, finally, the wastewater is subjected to the regular treatment that all drinking water currently undergoes.
"Quite honestly, it'll be the cleanest drinking water around," said Darrin Polhemus, deputy director of the state's Division of Drinking Water.
The 62 pages of proposed rules, more than a decade in the making, are not triggering much, if any, debate among health or water experts. A panel of engineering and water quality scientists deemed an earlier version of the regulations protective of public health, although they raised concerns that the treatment process would be energy-intensive.
"I would have no hesitation drinking this water my whole life," said Daniel McCurry, an assistant professor of civil and environmental engineering at the University of Southern California.
I wonder which is more expensive, purifying sewage or desalination? Its probably better to get the sewage turning into something less toxic and let the ocean be the ocean.