Re: SBSA Findings

From: Ken Poulton (poulton@zonker.hpl.hp.com-DeleteThis)
Date: Wed Feb 11 1998 - 11:09:24 PST


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Date: Wed, 11 Feb 1998 11:09:24 -0800 (PST)
From: Ken Poulton <poulton@zonker.hpl.hp.com-DeleteThis>
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To: sandul@astreet.com-DeleteThis
Subject: Re:  SBSA Findings
Cc: jbackusb@aol.com-DeleteThis, kjkaufman@aol.com-DeleteThis, sandul@azstarnet.com-DeleteThis, wind_talk@opus.hpl.hp.com-DeleteThis
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Duane, thanks for the update.

I'm having a hard time drawing the same conclusions from the data,
however. Can you help me understand the reasoning here?

First, what happened to the monitoring station north of the SM
bridge where the windsurfing actually occurs?

> Study's Conclusions:

> water contact recreation beneficial use (200 MPN/100mL log mean)
> remained fully protected when the plant discharged daily fecal coliform
> concentrations as high as 16,000 MPN/100mL.

The graph shows a peak of only 3000 MPN/100mL.

> The study (conducted from August 1996 through September 1997 and since then
> under analysis) demonstrates the lack of correlation between SBSA plant
> effluent fecal coliform levels and receiving water fecal coliform levels.

The one time when effluent levels went above the proposed 500 MPN/100mL,
the levels in the 3 nearer Bay monitoring stations go up by a factor of
4 over the baseline level, while the farthest station showed less than a
2x increase. This is still well below the water contact standard, but
it seems to show that levels above 500 MPN/100mL *can* have a real effect.

In the summer trial of higher coliform levels, the level only approached
500 MPN/100mL for about 3 weeks. The rest of the time it was below 200.

So far, it appears to me that a target level of 500 MPN/100mL may
be too agressive for the study done to date. Could substantial
savings in chlorine use (and effluent) be achieved with a 100 MPN/100mL
target?

Again, thanks for keeping us informed.

Ken Poulton
poulton@opus.hpl.hp.com-DeleteThis



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