‘Toilet-to-tap’ water purification coming to San Francisco Bay Area

Supposedly the water won’t be used for drinking, but that would seem to involve a fair amount of re-plumbing.

CBS-San Francisco reports:

The source for Santa Clara County’s newest, cleanest and virtually limitless water is the new $68 million sewage treatment plant near Alviso, but the ultra clean water won’t be going into homes due to the stigma regarding recycled water.

The new Silicon Valley Advanced Water Purification Center will open this fall, but due to public perceptions, the water from the plant will be diverted for use in fire hydrants, landscaping and electrical fountains instead of homes.

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13 thoughts on “‘Toilet-to-tap’ water purification coming to San Francisco Bay Area”

  1. I am not sure there is anything wrong with this. The water turns out cleaner than water from “fresh” sources, and with water scarcity issues in CA – it can be bad even if the greens allowed the peripheral canal, l think it is actually a good idea if it is cost competitive with other water sources.

  2. Speaking as the holder of both a potable and a wastewater license. This isn’t a trivial concern. Marque, I have to err on the side of caution here. I’ve seen far too many overflows, bypasses, exceedances, and similar problems to not be concerned. While potable water requirements have strict sampling and testing requirements, it would be all too easy to have an overflow after a rainstorm and get contamination in the potable system. You could detect it and shut it down, but not before potentially getting a lot of people sick.

    It’s not that it’s a bad idea in general, but I have to withold judgement on a particular system until I trust their system.

    Now Steve, if San Fransisco already has a citywide greywater system, then the diversion is simple enough. This is non-potable but still usable water diverted for non-human consumption. The installation is expensive, but it enables water reuse and significant cost savings in water-scarce areas. I don’t know whether they ever finished it, but Austin was planning to install one a few years ago.

  3. Do you really think they put in two distribution systems to handle gray water and potable water in San Francisco? Holly Springs, NC, has a gray water distribution system. It is in a much more limited area and, I believe, only goes to certain places. San Francisco would be very difficult to do or retrofit. They are using UV disinfection which is great for purifying clean water, but has no ability to handle subsequent contamination. So, I too, wonder how they plan to handle the overflow/bypass/oops scenarios.

  4. When I was in San Francisco years ago, I asked why all the overhead wiring, when most of the country had undergrounded their utilities.

    One word: earthquakes.

    New water infrastructure in San Fran would be a lot more difficult than elsewhere. Perhaps prohibitive.

  5. When I lived in the Santa Clara Valley (Sunnyvale) in the 1960’s, there was no separate water system for potable water (‘white’ water) and non-potable water (‘grey’ water). Sewage (‘black’ water) has its own system. I do not recall such a project in the interim. I suspect the promise that the grey water will not go to the taps promise is bogus.

  6. A lot depends on how “white” that “grey” water is. The space station recycles pretty nearlyl every drop as I understand. Water from surface features and even from aquifers is likely to have been some animals’ toilet at some point or another, which is why wise hikers purify any water they find to use in the wild.

  7. I never underestimate the ability of hippies to spend other people’s money on marginally beneficial projects (and this one would actually have benefits). However, actually looking it up, they don’t have anything of the sort. So, while it’s not unprecedented to do it, they simply don’t have the infrastructure needed to pull it off, and right now they don’t have the money to fund that scale of a project.

  8. The newer developments in the rest of the bay area are all underground. I think new developments post 1978 are all under ground. They just don’t want to pay the money to dig up the streets.

  9. The answer is to purify it to drinkable standards and put it in the regular water system. this was tested successfully in San Diego but the system was scuttled by Junk Science proponents and their scare stories.

    This isn’t as hard as you are all making it out to be.

  10. I can see them forging ahead with this. This is the same city that has lots of people wanting to take out Hetch Hetchy dam in Yosemite. The very dam that collects their very clean drinking water.

  11. “The new Silicon Valley Advanced Water Purification Center will open this fall, but due to public perceptions, the water from the plant will be diverted for use in fire hydrants, landscaping and electrical fountains instead of homes.”

    This, the topic of the thread, is what we are reacting to.

    But, if I understand you right, it does make sense that the water could be used as input to the “regular water system.” Just like they might pull water from a river as input. Sewage treatment plant direct to households is asking for trouble.

  12. Mr. Milloy … I can’t tell if you are for or against using treated wastewater to augment potable water supplies. It’s easy to scare people with the ‘toilet-to-tap’ label, but where do you stand on this?

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