# Homework Help: Calc. the effluent inert particulate conc. from a CSTR w/w/o solid liquids separation

1. May 9, 2010

### rzbizzy

Hi, I have no idea how to do this complicated problem. Help would be greatly appreciated. Thanks.

1a)Calculate the effluent inert particulate concentration (Xi, mg COD/L) from a CSTR (volume
V = 1000 L ), operating without solids liquids separation, fed with inert particulate matter (Xi,o = 10 mg COD/L). The influent flow to the reactor, Q, 1000 L/d.

1b): Re-calculate XI if the same reactor is now operated with solids-liquids separation such that the solids retention time, θx is 10 d; all other parameters stay the same.

So I have:
initial Xi,o = influent inert particulate matter = 10 mg COD/L
V = 1000 L
Q = influent flow to the reactor = 1000 L/d
effluent XI = effluent inert particulate matter = ?

I know that
rate of mass accumulation in control volume = rate(s) of mass in - rate(s) of mass out + rate(s) of mass generation.

So, something like V = QinXin - QoutXout + ????

I'm sure this has something to do with part a and b, but I have no idea how to go about it.