Water Quality Problem

walrus102882 · Oct 18, 2016

Can any one help me understand how to solve this problem found in Six Minute Solutions?

A chemical formula typically used to represent biomass is given as C5H7O2N. What is the most nearly the daily nitrogen requirements if the wastewater contains 310 mg/l accetic acid abd the flow rate is 12000 m^3/d?

I do have the answer in the book and i do not understand how they got there.

Thanks

ericchow · Oct 19, 2016

I'm not sure about this one, but it seems like you need to know the chemical equation for C5H7O2N and acetic acid and nitrogen, convert 310 mg/L acetic acid to moles, find how many moles of nitrogen are needed, then convert to a mass of nitrogen using molecular weight. I would definitely get this one wrong though because I couldn't find the chemical equation in CERM and I don't know how to write it out.

matt267 PE · Oct 19, 2016

Can you scan the answer and post it? My copy is at work.

walrus102882 · Oct 20, 2016

I attached the solution.

Thanks

View attachment Solution.doc

matt267 PE · Oct 20, 2016

Yeah, this is more of a chemistry problem than an engineering problem. This is a stoichiometry problem. At what point of the solution are you getting stuck?

Please note that for the WRE exam, the Six Minute Solution problems are much, much harder than the actual exam problems.

snickerd3 · Oct 20, 2016

where do you get lost? Acetic acid is CH3COOH there are 2 C in 1 acetic acid...that's where that fraction is coming from and 5C to 1N for the other.

walrus102882 · Oct 20, 2016

@snickerd3 @matt267 PE

I approached the problem trying to balance the reaction first and that is what had my thrown off. After doing some reading and working some chemistry problems I understand my mistake.

Thanks!

matt267 PE · Oct 20, 2016

@walrus102882

Excellent. Good luck next week.

snickerd3 · Oct 20, 2016

exactly the sort of distraction they try to set up.

EnvEngrCA · Nov 7, 2016

The title of this thread should say "Wastewater Chemistry Question". Also, this seems way harder than anything on the PE.

matt267 PE · Nov 7, 2016

Ion_Exchange said:
this seems way harder than anything on the PE

Yes and no. This question as a whole likely wouldn't show up on the PE. But, any of the individual concepts/theories is fair game.

Water Quality Problem

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