Biomedical Engineering Reference
In-Depth Information
where t is time in days. The biomass in the G-Reactor decreased from 1.87 to 1.55 g/l within
approximately 6 days and remained constant thereafter. A slightly higher effluent SS of 58 ±
27 mg/l existed in the N-Reactor than that of 35 ± 21 mg/l in the G-Reactor.
The higher effluent biomass concentrations and lower biomass concentrations inside the
reactor caused the lower SRT in the N-Reactor compared to that in the G-Reactor (Figure 6).
The SRT in the N-Reactor ranged from 4 to 20 days, while that in the G-Reactor ranged from
19 to 25 days. The relationships between SS and SRT in the N-Reactor are presented in
Figure 7, which shows that the lower biomass concentration in the N-Reactor was mainly
caused by the low SRT.
1.6
SS = 0.09SRT - 0.44
R 2 = 0.76
1.2
SS
Removed total SS
0.8
TrSS = 0.01SRT + 0.02
R 2 = 0.36
0.4
0.0
4
6
8
10
12
14
16
18
20
SRT (day)
Figure 7. Relationships between the sludge retention time (SRT) and the biomass in reactor (SS) and
total removed biomass per day (TrSS) in the N-Reactor.
The high effluent SS from the N-Reactor could be due to the poor settlement of activated
sludge flocs in the N-Reactor compared to the G-Reactor, which was reflected by the slightly
higher SVI of 218 ± 24 ml/g in the N-Reactor than that of 171 ± 52 ml/g in the G-Reactor.
3.4. Morphology and Extracellular polymeric Substances of Activated
Sludge Flocs
The morphology of activated sludge flocs taken on Day 32 is shown in Figure 8. There
were two types of floc forms presenting in the N-Reactor: one type was granular and the other
type comprised small-dispersed particles. In the G-Reactor, most flocs were bridged together
and formed larger particles.
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