Thesis - faculty.ait.ac.th - Asian Institute of Technology

y:
Where:
OUR at line g: This is the maximum respiration rate observed at the start-up of the
respiration cycles. At this point all oxidative reactions take place,
including the oxidation of carbon and nitrogen.
Time T: The time for the sample to reach an endogenous respiration rate.
Specific OUR of substrate oxidation at a substrate concentration S (OURx,ox) is given
OUR X , ox OURX
, t − OURX
, e
= (C-1)
OURx,t = Total respiration rate (mg O2/mg VSS.h)
OURx,e = Endogenous respiration rate (mg O2/mg VSS .h)
Further specific substrate removal rate at a substrate concentration S (RX) is given by:
OURX
, ox
RX
=
OC / S
(C-2)
Where
RX = Substrate removal rate (mg COD removed/mg VSS.h)
OC = Net oxygen consumption (mg O2/L)
S = Substrate concentration (mg COD/L)
OC is then equal to the area between the OUR curve and the second plateau level
where the OUR decreases rapidly and levels off (OC = Area A+area B) (Figure C-1)
Biomass yield coefficient (Y) is expressed as:
1 ⎛ OC ⎞
Y = ⎜1−
⎟
f ⎝ S ⎠
and the specific growth rate (µ ) as:
(C-3)
µ = Y. R
(C-4)
X
Where
µ = Specific growth rate (h -1 )
f = COD/VSS ratio of the sludge (mg COD/mg VSS)
Y = Yield coefficient (mg VSS/mg COD removed)
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