Flush with recycling ideas
As cities boom and climate changes, reusing wastewater looking like a viable option
DENVER — Around the country, cities are increasingly warming to an idea that once induced gags: Sterilize wastewater from toilets, sinks and factories, and eventually pipe it back into homes and businesses as tap water.
In the Los Angeles area, plans to recycle wastewater for drinking are moving along with little fanfare just two decades after similar efforts in the city sparked such a backlash they had to be abandoned. The practice, which must meet federal drinking water standards, has been adopted in several places around the country, including nearby Orange County.
“We’ve had a sea change in terms of public attitudes toward wastewater recycling,” said David Nahai, the former general manager of the Los Angeles Department of Water and Power.
The shifting attitudes around a concept once dismissively dubbed “toilet to tap” come as dry regions scramble for ways to increase water supplies as their populations boom and climate change intensifies droughts. Other strategies gaining traction include collecting runoff from streams and roads after storms, and stripping seawater of salt and other minerals, a process that’s still relatively rare and expensive.
Though there are still only about two dozen communities in the U.S. using some form of recycled water for drinking, that number is projected to more than double in the next 15 years, according to WateReuse, a group that helps cities adopt such conservation practices.
In most places that do it, the sterilized water is usually mixed back into a lake, river or other natural source before being reused — a step that helps make the idea of drinking treated sewage go down easier for some.
Funding for more wastewater recycling projects is on the way. The bipartisan infrastructure bill passed by Congress has $1 billion for water reuse projects in the West, including the $3.4 billion project in Southern California.
In Colorado, over two dozen facilities already recycle water for non-drinking purposes, which is more affordable than cleaning it for drinking. But growing populations mean cities could need to pull additional supply from the Colorado River, which is already strained from overuse.
At that point, it might make sense to start recycling for drinking purposes as well, said Greg Fisher, head of demand planning for Denver Water.
To warm residents to the idea, Colorado Springs Utilities is hosting a mobile exhibit that shows how wastewater recycling works. On a cold, rainy afternoon, dozens of visitors showed up to learn about the carbon-based purification process and sample the results, which several noted tasted no different than their usual supply.
The recycling process typically entails disinfecting wastewater with ozone gas or ultraviolet light to remove viruses and bacteria, then filtering it through membranes with microscopic pores to remove solids and trace contaminants.
Not all water can be recycled locally. Often, Western communities are required to send treated wastewater back to its source, so that it can eventually be used by other places that depend on that same body of water.
“You have to put the water back into the river because it’s not yours,” said Patricia Sinicropi, executive director of WateReuse.