Environmental Engineering Reference
In-Depth Information
Figure 6.15
Gas evolution data (filled symbols) plotted as percent
mineralization for the biodegradation of bleached paperboard packaging
material in a respirometer. Soil media (70 wt% humidity) with sewage
sludge inoculum was used. Also included is a plot of the data (open
symbols) as suggested by
Equation 6.2
.
Source: Reproduced with permission from Andrady and Song (1999).
Biodegradability of the substrate is calculated as percentage of the overall
CO
2
production based on the determined carbon content of the samples.
The value needs to be corrected for endogenous emissions from inoculum
and medium, obtained from the control flask. The time dependence of the
carbon conversion
C
m
is given by:
(6.5)
where
k
is the rate constant,
C
m
the percent biodegradability of the
substrate,
a
and
c
, constants. The value of
k
can be conveniently obtained by
plotting the data as follows (see
Fig. 6.15
).
