The COD, TKN and FSA concentrations of the original composite sample $($raw sewage$)$ and decanted supernatant sample

$($like settled sewage$)$ and $0\mathrm{.}45$ micron membrane filtrate were tested and found to be as follows:

Set$+$Non Set$+$Non

Table $1$ COD TOC VFA TKN FSA TP OP TSuspS ISuspS

Raw Sewage $750250\mathrm{.}8--------60\mathrm{.}0--------12\mathrm{.}00--------416\mathrm{.}460\mathrm{.}0$

Decanted Supernatant $475158\mathrm{.}8--------50\mathrm{.}0--------9\mathrm{.}60--------189\mathrm{.}215\mathrm{.}0$

$0,45$ m membrane filtrate $21071\mathrm{.}950\mathrm{.}044\mathrm{.}039\mathrm{.}18\mathrm{.}237\mathrm{.}28----------------$

Units mgCOD$/$l mgC$/$l mgCOD$/$l mgN$/$l mgN$/$l mgTSS$/$l mgIS$/$l

$3$a Calculate the COD, TOC, TKN and FSA of the suspended material retained on the $0,45$ m filter membrane.

$3$b Calculate the $\%$ settleable, suspended and soluble COD, TOC, TKN and TP fractions for the raw and settled wastewaters $($WW$).$

Plot the raw and settled WW results in the physical characterization triangles for the COD, TOC, TKN and TP$.$

$3$c Calculate the FSA$/$TKN ratio of the raw and settled sewages. Why is the FSA concentration the same in the raw and

settled sewages, but the TKN concentration different? Why is so much more COD and TOC removed in primary

sedimentation than TKN$?$

$3$d What are the $\%$ soluble and $\%$ particulate fractions of the organic N in the raw and settled sewages? What is the

percentage orgN removal in the settlement? How does the $\%$ organic N removal compare with the $\%$ COD removal?

What do you conclude when you compare the $\%$ TKN and $\%$ organic N removal with $\%$ COD removal in $1$ h settlement?