1. AIM
To evaluate the changes in the bacterial community, the 4-Chlorophenol (4-CP)
degradation rate, effluent suspended solids, respirometric activity and settling velocity
of aerobic granules during the degradation of 4-CP synthetic water, when the common
SBR operation is changed to an optimal control operation.
INTRODUCTION
The conventional aerobic wastewater treatment processes fail when they are
exposed to high contaminant concentrations, that results inhibitory and toxic for the
microorganisms. This problem can be solved by strategies like cellular immobilization
[1], that is the case of the aerobic granulation.
The aerobic granules are microbial origin aggregates that does not coagulate under
low hydrodynamic shear forces and that settle faster than flocculent sludge [2]. The
aerobic granules have been cultivated only in sequencing batch reactors (SBR) [3],
inin which all metabolic
METHODOLOGY
RESULTS
• Degradation and 4-CP kinetics
*Laboratorio de Investigación en Procesos Avanzados de Tratamiento de Aguas, Instituto de Ingeniería, Unidad Académica Juriquilla, Universidad Nacional Autónoma de México. Blvd
Juriquilla 3001, Querétaro 76230, México.
$ Instituto de Ecología, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria. Coyoacán, Ciudad de México 04510, México.
Víctor S. García Rea*$, Luisa Falcón $, German Buitrón* and Iván Moreno Andrade*
CONCLUSIONS
•A shift in the microbial population of aerobic granules degrading 4-CP when a
control strategy was used were observed, presenting an augmentation of the
genders of the 4-CP bacterial degraders.
•The new community is phylogenetically similar to the first one, so despite the
genders differences the metabolic and functional activity is preserved..
•Changes were registered from one operation strategy to the other in the 4-CP
degradation rate, effluent suspended solids, respirometric activity and settling
velocity. The removal percentage of 4-CP were kept in more of the 99.5% for both
strategies, although the ED-TOC strategy is more robust for more elevated
concentrations. .
REFERENCES
1. Moreno-Andrade, I., G. Buitron, A. Vargas, Effect of starvation and shock loads on the biodegradation of 4-chlorophenol in a discontinuous
moving bed biofilm reactor. Appl Biochem Biotech, 2009. p. 222-30.
2. de Kreuk, M.K., et al., Discussion outcomes. Ede. In: Aerobic Granular Sludge. Water and Environmental Managment Series2005: IWA
Publishing.
3. Adav, S.S., et al., Aerobic granular sludge: recent advances. Biotechnol Adv, 2008. p. 411-23.
4. Moreno-Andrade, I., et al., Optimal degradation of inhibitory wastewaters in a fed-batch bioreactor. J Chem Technol Biot, 2006. p. 713-720.
in which all metabolic reactions and solid-liquid
separations take place in one tank, with a well-
defined and continuously repeated step
sequence.
In the SBR, the inhibitory compound
degradation could be optimized by means of a
filling/feeding mode that maintains at the
maximum value the pollutant degradation rate
(q) [4]. Unlike the common operation strategy
or FTC (Fixed time control) (fig. 1), the ED-
TOC (Event driven time optimal control)
strategy achieves this optimization by
adjusting the influent flow such a way that an
inhibitory by control) logra estainhibitory concentration is never exceeded and the pollutant degradation rate is
maintained around the maximum value [4].
FTC Kinetics
0 100 200 300 400
0
50
100
150
200
250
380 mg/L
450 mg/L
300 mg/L
Time (min)
4-CF[mg/L]
TRACING OF GRANULAR BIOMASS IN A SBR DEGRADING INHIBITORY
4-CHLOROPHENOL SYNTHETIC WASTEWATER USING TWO DIFFERENT
OPERATION STRATEGIES
• Physicochemical and molecular biology results
• Microscopy and CLSM
Figure 2. Aerobic granule photography (A), granular surface CLSM 20X (B) and
fluorescence microscopy performed in an aerobic granular section: FITC (green-
protein staining) and Calcofluor White (blue-carbohydrate staining) (C).
20X100 mm
A B C
Effluent suspended solids
FTC vs ED-TOC
FTC ED-TOC
0
10
20
30
40
SS(mg/L)
n=25, bars 95% confidence interval
FTC vs ED-TOC respirometry
FTC ED-TOC
0
100
200
300
mgO2/gSSVh
n=10, bars 95% confidence interval
FTC vs ED-TOC settling velocity
0 50 100 150
0
20
40
60
80
100 FTC
ED-TOC
Operation day
Setvel(m/h)
ED-TOCFTC
A B
ED-TOC
0
FTC
46F-534R primersTX9-1391R primers
Figure 4. DGGE, 40-60% denaturant gradient.
4-CP influent
[mg/L]
4-CP effluent
[mg/L] FTC
Removal
percentage (FTC)
4-CP influent
[mg/L] ED-TOC
Removal
percentage(ED-TOC)
300-500 0.14 +/- 0.11 99.81 +/- 0.03 % 0.41+/- 0.08% 99.81+/-0.09%
Table 1. 4-CP removal in both strategies. Average with 95% confidence interval, n>60.
q= 1190 +/- 300 mg4CF gSSV-1 d-1
0
5
10
15
20
25
Clonepercentage
ED-TOC reactor microorganisms Fila
Fila
0
2
4
6
8
10
12
Clonepercentage
FTC reactor microorganisms
Figure 3. CLSM of granular sections of 40 mm width. Protein/nucleic acid stain (DAPI)
(A, C), and protein/carbohydrate satin (B).
63X
B
25X
B
63XA B C
50 mm 20 mm 20 mm
Comparation
0 25 50 75 100 125 150 175 200 225 250
0
20
40
60
0
2
4
6
O2
4-CF
Cinética ED-TOC
tiempo (min)
4-CF[mg/L]
O2[mg/L]
ED-TOC Kinetics
q= 714 +/- 100 mg4CF gSSV-1 d-1
2
T Time (min)
Acknowledgments
Authors want to thanks to: Consejo de Ciencia y Tecnología del Estado de Querétaro (CONCyTEQ) and
CONACyT scholarship for economic support; and MSc. Jaime Pérez, and MSc. Osiris Gaona for all the technical
support given.
Figure 1. FTC (A) vs ED-TOC (B) operation
scheme.
Slow reaction
Quick fill
A
Optimal degradation
B
Degradation
with inhibition
E-mail: serman13@hotmail.com