Biomedical Engineering Reference
In-Depth Information
The EPS content in the biomass taken from both reactors is shown in Figure 9. The total
EPS (carbohydrate + protein) proportion was 24.0% in the N-Reactor and 12.6% in the G-
Reactor. There was little difference in the protein proportion in both reactors: 1.9% in the N-
Reactor and 2.6% in the G-Reactor. However, the carbohydrate proportion was significantly
different in both reactors: 22% in the N-Reactor and 10% in the G-Reactor.
The average carbohydrate/protein ratios in the EPS were 12.0 ± 1.1 in the N-Reactor and
3.8 ± 0.4 in the G-Reactor. The carbohydrate/protein ratio could be correlated to SVI in both
reactors (Figure 10).
300
SVI = 85.8 PC - 153.6
R 2 = 0.99
250
200
150
SVI = 19.3 PC - 11.3
R 2 = 0.62
100
N-Reac tor
G-Reactor
50
0
0
3
6
9
12
15
Protein/Carbohydrate ratio
Figure 10. Relationships between the SVI and the protein/carbohydrate ratio (PC).
4. Discussion
4.1. Effect of the Glucose Addition on the Activity of Nitrification
Compared with the addition of glucose in the G-Reactor, a high specific nitrification rate
and a low volumetric nitrification rate were obtained in the N-Reactor without the addition of
glucose. This is similar to the result obtained by Wu et al. (2008a). The possible reasons
causing this phenomenon are: (1) the effect of carbon substrates; (2) the effect of the
distribution of microbial communities; and (3) the effect of SRT.
4.1.1. Effect of Carbon Substrates
The effect of carbon substrate on nitrification has been intensively investigated (Hanaki
et al., 1990; Nogueira et al., 2002). However, different results have been obtained from
different studies.
Search WWH ::




Custom Search