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# Environmental Solved Problems - HELP

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Can someone, anyone, help me identify the equations used for Problem 7 in the Environmental Engineering Solved Problems (Schneiter)??? Find the cross-sectional surface area for the filter (Wastewater/Stormwater Section)???

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Nope, I looked at my notes on that problem and all I had was "use equation in Solved Problems". It's been a long time, but it may very well have been one of those problems where I just punted, instead of wasting too much study time trying to figure out where it came from.

In other words, don't get too hung up on the occasional problem in Schneiter that you can't solve using the EnvERM. Try to find the source, but don't waste too much time or worry if you can't. Tab the page so you can reference that equation during the exam, and move on.

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Thanks. Sometimes I have no idea where the formula's come from, so it gets frustrating.

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My notes say Eq 26.19 in EERM. But looks like I skipped the problem in the end. Way more complicated than what you're likely to see on the exam in my opinion.

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Is this from the 101 solved problems book?

yes.

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In Problem #5 about the industrial WWTP:

Where can I find the the 7.7mg/L DO in water @ Temp=22C and elevation correction factor of 0.88 that they refer to in the solution? Initially I thought it would be App 22D.

Thanks

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also...for problem #12.1 (storage capacity) - how do they get 12,500m3 from the graph? I'd think 14,000.

thanks

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Any luck with this yet? I looked at EEERM table 36.1 but could not find the same factor...

In Problem #5 about the industrial WWTP:

Where can I find the the 7.7mg/L DO in water @ Temp=22C and elevation correction factor of 0.88 that they refer to in the solution? Initially I thought it would be App 22D.

Thanks

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Any luck with this yet? I looked at EEERM table 36.1 but could not find the same factor...

In Problem #5 about the industrial WWTP:

Where can I find the the 7.7mg/L DO in water @ Temp=22C and elevation correction factor of 0.88 that they refer to in the solution? Initially I thought it would be App 22D.

Thanks

The saturation of DO in water (in mg/L) at standard atmospheric conditions varies with temperature, for other pressures, the solubilities vary approximately in proportion to the ratios of these pressures to the standard pressures (Pactual/Pstandard).

So...According to App22.D @ 22C the DO content is 8.83 mg/L. I don't have the problem, but I am assuming that the pressure correction factor is given or derived from a simple ratio or the equation given at the bottom of App22.D...Therefore, the actual [DO] in the water would be Csactual = Csstandard (Pcorrection)

Csactual = 8.83 *(0.88)

= 7.77 mg/L DO

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Any luck with this yet? I looked at EEERM table 36.1 but could not find the same factor...

In Problem #5 about the industrial WWTP:

Where can I find the the 7.7mg/L DO in water @ Temp=22C and elevation correction factor of 0.88 that they refer to in the solution? Initially I thought it would be App 22D.

Thanks

The saturation of DO in water (in mg/L) at standard atmospheric conditions varies with temperature, for other pressures, the solubilities vary approximately in proportion to the ratios of these pressures to the standard pressures (Pactual/Pstandard).

So...According to App22.D @ 22C the DO content is 8.83 mg/L. I don't have the problem, but I am assuming that the pressure correction factor is given or derived from a simple ratio or the equation given at the bottom of App22.D...Therefore, the actual [DO] in the water would be Csactual = Csstandard (Pcorrection)

Csactual = 8.83 *(0.88)

= 7.77 mg/L DO

That's it! Thanks! Turns out I misread table 36.1 and it works just as well but now I know why. EngineerBoards.com is awesome!

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Occasionally, I earn my keep.

Good luck on the exam.