Flushed

Published: Wednesday, October 29, 2008 1:10 PM PDT

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No one is arguing that we can conserve our way out of the water crisis -- although that is where we must start. But if we move to the next tier, what does that look like? Call it water reuse, recycling, indirect potable reuse (IPR), reservoir augmentation, even the rather simplistic but catchy toilet-to-tap.

However you label it, the concept is simple: treating sewage to a level that's cleaner than our current drinking supplies, using the same technology as desalination plus a few steps to make the result even more pure. There has been a huge outpouring of support for taking water out of the ocean and treating it to a level suitable for drinking. But that's exactly where our slightly treated sewage is currently being disposed of -- in the ocean. And make no mistake; our sewage is not treated to federal standards before disposal.

It makes much more sense to treat sewage directly rather than dumping it in the ocean, then pulling it out a few miles away for treatment. IPR uses reverse osmosis, the same process involved in desalination. The problem is that desalination involves ocean water, which is four times more saline than sewage. Reverse osmosis requires far more pressure to treat the higher salt content of ocean water, the main reason for the energy (and cost) discrepancy between IPR and desalination.

From a purely economic standpoint, IPR makes sense. That's why businesses, trade associations like BIOCOM, and the San Diego County Taxpayers Association support it. Using the same state-of-the-art technology as desalination, but at a lower cost and without as much environmental impact, makes IPR the best choice for planned recycling.

In Orange County, the water district provides its ratepayers with drinkable treated wastewater at half the cost of imported water and half to a quarter the cost of desalinated water. One economic argument used against IPR in San Diego is that local governments would have to build the infrastructure. Desalination is a commercial enterprise, which means no up-front expenditure by local government. But therein lies the fallacy -- there's no such thing as a free lunch. If a private corporation is willing to build, it must be profitable, and the ratepayers (you and I) will have to pay for it down the road. Our locally proposed plant, in Carlsbad, is tied to the cost of imported water. The plant's owners are betting that the cost of that water is going to go up, meaning they can charge more for their water and eventually be profitable.

If the city of San Diego built a full-scale IPR project, or several satellite projects, it would save ratepayers money in the long run, given IPR's lower than desalination or imported water costs. The IPR hurdle isn't public support or technology; it's a failure to take the long-view.

-- GABE SOLMER

3 Comments so far on this story...

August 19, 2008 TO: U.S. Bureau of Reclamation FROM: Ray Walker, Retired Water Rights Analyst waterrdw@yahoo.com Subject: Lease of available space in Lake Mead Attn: Robert Johnson, Commissioner Robert Walsh, External Affairs Officer, Lower Colorado Region I wish to deliver and properly measure up to ONE MILLION ACRE FEET of fresh water to the Colorado River which is absolutely non-tributary to the Colorado River. In order to solve the water shortage dilemmas facing the region, I wish to store said non-tributary water in Lake Mead on a space available basis. ( Not enough space allowed to continue with rest of Lease request). P.S. check out Prions before you get excited about treating effluent !

Posted by WaterSource | reply to this comment
October 30, 2008 4:53 am

Recycling effluent is one thing…injecting it into the underground water supply is something to seriously reconsider.PRIONS may not be destroyed with current water treatment methods.Mad cow disease, CWD, scapes, kuru, FFI, GSSS and CJD are all prions. All known prion diseases, collectively called transmissible spongiform encephalopathies (TSEs), are untreatable and fatal ! Prions can be denatured by subjecting them to a temperatures of 134 degrees Celsius (That’s 273 F !… water boils at 212 F) for 18 minutes in a pressurized steam autoclave. The concern is that there’s so little known about prions, that we ought to be taking a protective, conservative approach.If anything goes wrong, contamination could render an entire underground aquifer inoperative. Ray Walker waterrdw@yahoo.com

Posted by WaterSource | reply to this comment
October 30, 2008 4:53 am

I was curious about this Ray Walker, Retired Water Rights Analyst, so I googled him and learn that he is a proponent of a special water resource he calls "Source". He claims to have a secret source of pure water for Nevada that can fill Lake Meade all by itself. His letter writing campaign to many newspapers in Nevada is clearly now spilling over to California. A Water Rights Analyst deals with law not science. Clearly a man with a special interest and no apparent expertise in public health. He insists he would disclose the information to the Bureau of Reclamation or other entitites but only if they will sign a non-disclosure agreement to keep the "Source" secret. He says he has been trying to get them to work with him for 5 years or more......

Posted by Judy S. | reply to this comment
October 30, 2008 9:27 am

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