Cities in the United States are increasingly turning to an idea that once sparked gags: sterilize wastewater from toilets, sinks, and factories, and eventually return it to homes and businesses as water. tap.
In the Los Angeles area, projects to recycle wastewater for consumption are advancing with fanfare just two decades after similar efforts in the city sparked such a backlash they had to be scrapped. The practice, which must meet federal drinking water standards, has been adopted in several locations across the country, including nearby Orange County.
âWe have had a radical change in terms of public attitudes towards wastewater recycling,â said David Nahai, the former general manager of the Los Angeles Department of Water and Electricity.
Changing attitudes around a concept once disdainfully dubbed ‘tap toilets’ come as dry regions scramble to find ways to increase water supplies as their populations explode and climate change intensifies droughts . stripping seawater salt and other minerals, a process that is still relatively rare and expensive.
While there are still only about 20 communities in the United States that use some form of recycled water for drinking, that number is expected to more than double over the next 15 years, according to WaterReuse, a group that helps cities to adopt such conservation practices.
In most places that do, sterilized water is usually mixed in a lake, river, or other natural source before being reused – a step that makes the idea of ââdrinking treated wastewater easier for some.
Funding for other wastewater recycling projects is ongoing. The bipartisan infrastructure bill passed by Congress provides $ 1 billion for water reuse projects in the West, including the $ 3.4 billion project in Southern California.
The pressure to keep came from Governor Gavin Newsom. Patrick Healy reports for the NBC4 News on Wednesday, September 22, 2021.
And in the federal budget reconciliation package being debated is $ 125 million in subsidies for nationwide alternative water sources that could include reuse technologies.
The Southern California project is said to be the largest wastewater recycling program in the country, producing enough water to supply 500,000 homes, according to the Metropolitan Water District, which serves 19 million people in Los Angeles and surrounding counties. .
In Colorado, more than two dozen facilities already recycle water for non-potable purposes, which is more affordable than cleaning it for drinking. But population growth means cities may need to draw additional supplies from the Colorado River, which is already strained by overuse.
At this point, it might be a good idea to start recycling for consumption as well, said Greg Fisher, demand planning manager 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 and rainy afternoon, dozens of visitors showed up to learn about the carbon-based purification process and sample the results, several of whom noted did not taste different from theirs. usual supply.
The recycling process typically involves disinfecting the wastewater with ozone or ultraviolet light to remove viruses and bacteria, and then filtering it through microscopic-pored membranes to remove solids and traces of contaminants.
Not all water can be recycled locally. Often, western communities are required to return treated wastewater to its source, so that it can eventually be used by other places that depend on that same body of water.
âYou have to put the water back in the river because it doesn’t belong to you,â said Patricia Sinicropi, Executive Director of WaterReuse.
As a result, much of the country is already consuming water that has been recycled to some extent, simply by living downstream from others. This is why drinking water undergoes rigorous sterilization even when it is drawn from a river or lake that looks clean.
Encouraged by efforts in other cities, even places with a stable water supply are considering recycling their own wastewater. After a poll showed broad support for the idea in Boise, Idaho, city officials began exploring plans to recharge local groundwater with treated wastewater.
âWe need to manage the potential impacts of climate change,â said Haley Falconer, senior executive in the city’s environmental division.
The Southern California project, which has yet to undergo an environmental review and finalize its financing plan, would also reduce the region’s need to deliver water remotely. In exchange for funding from the Nevada and Arizona water agencies, the region cedes part of its share of the Colorado River.
âWe take advantage of a water supply that is right here in our backyard,â said Deven Upadhyay, COO of the Metropolitan Water District.
Officials point out that the project uses technology that has been used safely elsewhere, including Israel and Singapore. Insurance became critical after a separate wastewater treatment plant in Los Angeles, which uses a different process to purify water for irrigation and industrial purposes, flooded and dumped sewage into the ocean. in July.
âThe last thing any of us wants is one of those projects that has a water quality issue that is hurting public perception,â Upadhyay said.