April 2011 home page

  Water Ways 
Henry Abarbanel | Crest Road


The conversation with David Scherer and Eric Minicilli from last month continues, and while it was intended to move from a focus on water to one on wastewater, they prove inseparable in the San Diego Region.

As many readers may recall the wastewater from Del Mar travels a tortuous route from the 21st St. pump station to the large waste water plant on Pt. Loma. Del Mar contributes 670,000 gal/day to this flow, and Pt. Loma treats 170,000,000 gal/day—yes we are insignificant in this one way.

Since 1972 the City of San Diego (SD), owner of the Pt. Loma plant has been receiving federal permission not to upgrade the treatment at Pt. Loma from just fine to super fine. The last waiver was just granted for a five year period. In the past SD has argued that any environmental damage to the ocean at the outfall five miles out is minimal, and scientific studies supported that claim. Now, working with the so-called “resource agencies” (California Fish and Game, the Regional Water Quality Board, and others) they argue that to go to the higher level of treatment would turn Pt. Loma into a net energy consumer rather than, as it is at present, a net energy generator. Thus if one looks at Pt. Loma as a part of a system rather than in isolation, upgrading the plant may cause more pollution in the region.

Energy producer? Yes, the methane from the existing treatment of wastewater is burned at Pt. Loma and provides the energy needed to run the plant plus energy that SDG&E buys as it is put into the grid. Upgrading the plant would give a large change in the energy consumed in those processes, for what would appear to be a small change in water quality. Indeed, there is an argument that one should use some of that locally generated energy to pump highly treated wastewater from Pt. Loma to local reservoirs where during a lengthy residence time, it would slowly enter the general water supply for the region. (See www.sandiego.gov/water/waterreuse/demo/ for details.)

In particular the Lake San Vicente reservoir, whose height is being raised by 117 feet to allow the reservoir to act as an emergency storage location and now part of a water reclamation/purification system. The initial project will produce 1,000,000 gal/day of potable water. The future of this kind of recycling of water may bring 10’s of million gal/day into our water supply which presently uses about 500,000,000 gal/day form mostly outside sources. So, folks, there is a long way to go, and water reclamation is only a part of a future water supply. However, it is a long, long way from the “know nothing” position of “toilet-to-tap” promulgated by right wing radio only a few years ago.

The other major new water source we can expect to see is desalinization of ocean water. The plant in Carlsbad which should be producing 10,000,000 gal/day soon with a short-term goal of 50,000,000 gal/day. Also plants in the South Bay and at Camp Pendelton will soon be adding to our water supply. The cost of deasal water is about $1200/acre-foot (acre-foot = 326,000 gallons) which is beginning to compare favorably to raw water directly from our County Water Authority at $800/acre-foot. The whole City of DM uses 1150 acre-feet each year.

Our ability to get water from sources beyond the traditional imports from the Colorado River and the Sierra Mountains will cost a lot of money, but if there is an alternative to our using water to live, the news has not come to Crest Road. In grand tradition many among us will want to have this essential and rare resource without paying for it, but it just won’t wash.

Back to David and Eric next month, and then we’ll introduce Eric on his own as the new DM Public Works Director.


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