Environmental Press # 292

Subj: Re: [sehbna] FW: CORRECTION to $540 re desal power requirements
Date: 7/25/2003 11:45:23 PM Pacific Daylight Time
From: Jon V3
To: sehbna@yahoogroups.com

In a message dated 7/25/2003 10:51:32 PM Pacific Daylight Time, johnscott@pickstation.net writes:

Source Water kWh/Million Gallons

Brackish Ground Water 2,840
Municipal Wastewater 3,067
Sea Water Desalination 13,215

I was struck by the same data. Sea water desalination requires four times the energy than treating municipal wastewater. It is clear that desalinating the ocean needs way more energy than treating wastewater, because the ocean is much saltier than wastewater. Ron Wildermuth of OCWD has also stated that desalination of ocean water is much more expensive than reclaiming wastewater, like $900-$1000 per acre foot for ocean versus $400-$600 per acre foot for wastewater. Given that each person in Orange County uses about 100 gallons of water a day, and there are 2.4 million people in OC, then the OC population needs 240 million gallons of water a day, exactly the amount which is being thrown away into the ocean each day through the

 

OCSD outfall. It would appear that recovery of wastewater and reclamation would go farther and be cheaper than desalination of the ocean, and also satisfy current demand for water in OC, with less ocean pollution to boot.

Jan

Back to T.O.C. 3