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To head off more dry years, water agencies explore toilet-to-tap

Agencies, cities tout method as helpful supplement if they can overcome "ick factor"

The cities of the Tri-Valley and their water agencies are searching for a way to avoid more punishing drought years. But one proposed method, while touted as a "drought-proof" water option, has to overcome the "ick factor" that affects public support.

The cities of Pleasanton, Livermore, Dublin and San Ramon, along with the Dublin San Ramon Services District (DSRSD), Zone 7 Water Agency and Cal Water's Livermore division, plan to research how to bring indirect potable reuse to the Tri-Valley. But the more common moniker -- detested by some water officials for the off-putting imagery -- is toilet-to-tap.

By reusing wastewater and treating it to drinking water standards, millions of gallons of water that is dumped into the San Francisco Bay each year could be kept in the Tri-Valley, according to Leonard Olive, Pleasanton's assistant director of operations services.

"There's only so much water. Water isn't just made," Olive said.

A public survey done in late 2015 to evaluate public opinion of toilet-to-tap across the Tri-Valley showed 63% of those polled support the idea of supplementing the region's water supply with treated reused water. Those that support the idea cite the drought as their main concern, but those that are against the idea say they are worried the process isn't safe -- or just can't get past the "ick factor," as the survey specifies.

One significant problem is the vast majority of the Tri-Valley's water supply -- about 80% -- comes from a state distribution system called the State Water Project. Zone 7, the water wholesaler for the Tri-Valley, doesn't have control over how much water the state sends, even during wet years.

DSRSD engineering services manager Dan McIntyre said indirect potable reuse could give local water agencies greater control over the region's water supply. During dry months, regional water agencies could have another source of drinking water, and excess water could be stored in the Livermore Valley's underground aquifer during wet months.

Researching the feasibility of toilet-to-tap is expected to cost about $500,000 -- to be shared among the region's water agencies -- and the actual cost will be determined when proposals are submitted later this spring, McIntyre said.

The process would consist of treating wastewater to drinking water standards through a specific filtration and disinfection process, then storing that water either in the underground aquifer or in Lake Del Valle, he said. The water would then be treated again when it is pumped into Zone 7 water treatment plants before it is sent to homes and businesses.

The proposed program would further treat such water through reverse osmosis or ozone filters, which brings the water up to drinking water standards, plus disinfecting with ultraviolet light, McIntyre said.

Doing such a process properly could require new infrastructure. DSRSD and the city of Livermore own reverse osmosis filters, but they haven't been used for 15 to 20 years, DSRSD operations manager Dan Gallagher said. Those facilities, along with a Zone 7 reverse osmosis filter that was active until a few years ago, could be upgraded and expanded.

The public survey, which polled 601 people who statistically represent the whole Tri-Valley, showed people were swayed to support toilet-to-tap when it was rebranded as "purified water" or when it was mentioned that astronauts and submarine crews drink reused, treated water, according to officials.

Indirect potable reuse would have additional treatment steps since the water would be put into a natural environmental barrier, Gallagher said.

If it's put into the underground aquifer, the water would trickle through many layers of soil before reaching the area where it is pumped back out to be sent to drinking water treatment plants. If it is sent to Lake Del Valle, it would mix with the lake water and would be treated again when it is pumped into drinking water plants.

One important distinction is indirect potable reuse is not the same as recycled water, Gallagher said.

Recycled water, such as the water that is distributed by DSRSD's residential recycled water program, is wastewater that is treated to remove solids and some impurities, but it does not meet drinking water standards and should only be used for irrigation or washing of hard surfaces.

But much of the water Tri-Valley residents drink now is unintentionally reused water, Olive said.

The region gets its water from Zone 7, and Zone 7 gets its water from the Sierra Nevada. But on its way to the Tri-Valley, the water from the Sierra snowpack gets used by northern cities like Sacramento, treated and dumped into the Delta, where it continues along -- being reused, treated and dumped several times through the process -- until it is deposited into Lake Del Valle.

He said the processes used by treatment plants cleans the water to drinking water standards with this reuse cycle in mind, and the proposed regional toilet-to-tap process would be a similar system.

"If you think about it, it's water that has received the treated effluent from Stockton," Olive said. "We're drinking the stuff right now, whether anybody wants to admit that or not."

Comments

2 people like this
Posted by Gary Chandler
a resident of Amador Estates
on Apr 1, 2016 at 8:08 am

Demand the truth in the risk assessments. [Portion removed due to promoting a website] Recycled wastewater recycles unstoppable brain disease.


1 person likes this
Posted by Jill
a resident of Carlton Oaks
on Apr 1, 2016 at 9:20 am

VERY happy to hear this! California's long-term solution for its water supply is to stop dumping it and start reusing it.

But I suspect it's inaccurate to say: "DSRSD and the city of Livermore own reverse osmosis filters, but they haven't been used for 15 to 20 years, DSRSD operations manager Dan Gallagher said. Those facilities, along with a Zone 7 reverse osmosis filter that was active until a few years ago, could be upgraded and expanded."

It's probably reverse osmosis filtration EQUIPMENT. The filters/membranes themselves probably don't last forever and need to be replaced regularly


6 people like this
Posted by Not Crazy
a resident of Southeast Pleasanton
on Apr 1, 2016 at 11:23 am

Using treated toilet water as drinking water is a bad idea. I am okay using this water to flush the toilet again, car wash or irrigation. Use the water in the purple line.


5 people like this
Posted by concerned
a resident of Stoneridge
on Apr 1, 2016 at 11:33 am

Agree with Gary Chandler and "not crazy". The link to the article is great information. Use this treated toilet water for the purple irrigation line. NOT in my kitchen or bathroom faucets!


2 people like this
Posted by Timothy T
a resident of Downtown
on Apr 1, 2016 at 1:31 pm

Lots of cities are already doing this with no negative effects. People do need to get over it as the water is often cleaner than the water that enters the system right now.

If we're going to move towards a sustainable future, then this is a sure thing.


5 people like this
Posted by Patriot
a resident of Birdland
on Apr 1, 2016 at 1:35 pm

On with the study and of desalinization as well. We are facing a drought for many years and must find new ways to have more water. Getting all our information from the internet is not the answer. Just scaring people with unscientific "articles" from the web authored by who knows who will not solve this issue. We have enough misinformation all around us this election year, so on with a real fact study.


1 person likes this
Posted by Snoopygirl
a resident of Amador Valley High School
on Apr 1, 2016 at 2:58 pm

Instead of making people drink treated waste water, of which the thought gags me, why don't you submit a moratorium on building new homes and swimming pools. I worked at the City of Saratoga, CA in the 70's, and when there was a water shortage during those years, there was a moratorium put on all new home building and new swimming pool building. The Saratoga Fire Department would even be able to pump water out of residents' pools, if needed, for a fire. Instead of creating urban sprawl and have more people more into the Tri-Valley area and use more resources, look at, what is, a more viable solution. I am appalled at the water treatment suggestion. Do the right thing and stop the UNNEEDED urban growth!!


7 people like this
Posted by VS
a resident of Pleasanton Valley
on Apr 1, 2016 at 3:22 pm

Only issue I see which has never been addressed in discussion of this water is what happens to viruses and medications.

There is no filter out there I am aware of which is small enough to get viruses. Once in spore form, viruses are VERY difficult to eliminate.

As far as medications, they are complex structures. How good are the current tests to pick out any residue from the medications in the water? Remember we have been warned not to dump old medications down the toilet to get rid of them because they will build up resistances in the current bacteria out there. There are folks out there who do it anyway. Why would I want to purchase purified water through Zone 7 or anywhere that hasn't been tested to remove the medications? Is there someplace we can check to get this information?


2 people like this
Posted by GetOverIt
a resident of Foothill High School
on Apr 1, 2016 at 6:26 pm

Ever been to Las Vegas? The Southern Nevada Water Authority pulls its water from Lake Mead. Where do you think they do with their treated wastewater? They put it back in Lake Mead.

Ever been to a city along the Mississippi River -- St Louis, Memphis, Baton Rouge, New Orleans. . . .? They all get drinking water from the Mississippi River and put their treated wastewater back into the same river.

Get over it.


Like this comment
Posted by Why Not Catch Run Off
a resident of Canyon Oaks
on Apr 4, 2016 at 1:33 pm

Before all the lemmings jump on the "toilet-to-tap" bandwagon, how about some serious consideration of capturing the rain water that currently ends up in arroyos.

The piping is already in place, all that is required is to catch it near the outfall, just before it would otherwise go into the arroyo. Pump it back to some storage and treatment facility that does pre-treatment to remove such things as oil drippings from automobiles, and various other contaminants. Existing treatment facilities can do the rest.

Possibly the water could be allowed to filter into ground water, but the government in Sacramento has already taken control of that so we might not benefit from injection of this additional water.

We need to become more independent of the politics of Sacramento when it comes to our water.


Sorry, but further commenting on this topic has been closed.

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