Revista Mexicana de Vol. 12, No. 1 (2013) 97-104 ... · Revista Mexicana de Ingeniería Q uímica...
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Revista Mexicana de Ingeniería Química
CONTENIDO
Volumen 8, número 3, 2009 / Volume 8, number 3, 2009
213 Derivation and application of the Stefan-Maxwell equations
(Desarrollo y aplicación de las ecuaciones de Stefan-Maxwell)
Stephen Whitaker
Biotecnología / Biotechnology
245 Modelado de la biodegradación en biorreactores de lodos de hidrocarburos totales del petróleo
intemperizados en suelos y sedimentos
(Biodegradation modeling of sludge bioreactors of total petroleum hydrocarbons weathering in soil
and sediments)
S.A. Medina-Moreno, S. Huerta-Ochoa, C.A. Lucho-Constantino, L. Aguilera-Vázquez, A. Jiménez-
González y M. Gutiérrez-Rojas
259 Crecimiento, sobrevivencia y adaptación de Bifidobacterium infantis a condiciones ácidas
(Growth, survival and adaptation of Bifidobacterium infantis to acidic conditions)
L. Mayorga-Reyes, P. Bustamante-Camilo, A. Gutiérrez-Nava, E. Barranco-Florido y A. Azaola-
Espinosa
265 Statistical approach to optimization of ethanol fermentation by Saccharomyces cerevisiae in the
presence of Valfor® zeolite NaA
(Optimización estadística de la fermentación etanólica de Saccharomyces cerevisiae en presencia de
zeolita Valfor® zeolite NaA)
G. Inei-Shizukawa, H. A. Velasco-Bedrán, G. F. Gutiérrez-López and H. Hernández-Sánchez
Ingeniería de procesos / Process engineering
271 Localización de una planta industrial: Revisión crítica y adecuación de los criterios empleados en
esta decisión
(Plant site selection: Critical review and adequation criteria used in this decision)
J.R. Medina, R.L. Romero y G.A. Pérez
Revista Mexicanade Ingenierıa Quımica
1
Academia Mexicana de Investigacion y Docencia en Ingenierıa Quımica, A.C.
Volumen 12, Numero 1, Abril 2013
ISSN 1665-2738
1Vol. 12, No. 1 (2013) 97-104
SIMULTANEOUS AMMONIUM AND p-HYDROXYBENZALDEHYDE OXIDATIONIN A SEQUENCING BATCH REACTOR
OXIDACION SIMULTANEA DE AMONIO Y p-HIDROXIBENZALDEHIDO EN UNREACTOR DE LOTES SECUENCIADOS
S.K. Tellez-Perez, C.D. Silva and A.C. Texier∗
Universidad Autonoma Metropolitana-Iztapalapa, Departamento de Biotecnologıa, Division CBS, Av. San RafaelAtlixco 186, Col. Vicentina, C.P. 09340, Mexico D.F., Mexico.
Recibido 25 de Enero de 2012; Aceptado 22 de Noviembre 2012
AbstractThe simultaneous ammonium and p-hydroxybenzaldehyde (pOHBD) oxidation capacity of a nitrifying sludge was investigated ina sequencing batch reactor (SBR). At all initial pOHBD concentrations tested (25-400 mg C/L), both ammonium (100 mg NH+
4 -N/L) and pOHBD were consumed with efficiencies of 99.2±1.5 % and 100±1 %, respectively. At pOHBD concentrations lowerthan 100 mg C/L, the main product of ammonium oxidation was nitrate with a yield (YNO3 ) of 0.97 ± 0.03 g NO−3 -N/g NH+
4 -Nconsumed. At 200 and 400 mg pOHBD-C/L, YNO3 decreased to 0.78± 0.05 and nitrite was detected (YNO2 = 0.04± 0.01 g NO−2 -N/g NH+
4 -N consumed). p-Hydroxybenzoate (pOHBT) was detected as product of pOHBD oxidation. pOHBT accumulationwas significant in the first operation cycles at 25 mg pOHBD-C/L. Afterward, pOHBT was completely removed and no aromaticintermediates were detected. At low C/N ratio values (0.25-4), a dissimilatory nitrifying respiratory process was maintained(YBM = 0.03 ± 0.01 g biomass-N/g NH+
4 -N consumed). These results show that nitrifying SBR can be successfully used forthe simultaneous removal of ammonium and p-hydroxybenzaldehyde in a unique reactor. This information might be useful fortreating industrial wastewaters contaminated with nitrogen and recalcitrant phenolic compounds.
Keywords: ammonium, biological oxidation, p-hydroxybenzaldehyde, nitrification, sequencing batch reactor.
ResumenLa capacidad de un lodo nitrificante para oxidar simultaneamente amonio y p-hidroxibenzaldehido (pOHBO) fue evaluada enun reactor de lotes secuenciados (SBR). A todas las concentraciones ensayadas (25-400 mg C-pOHBO/L), el amonio (100 mgN-NH+
4 /L) y el pOHBO fueron consumidos con eficiencias de 99.2 ± 1.5 % y de 100 ± 1 %, respectivamente. Hasta 100 mgC-CpOHBO/L, el nitrato fue el principal producto de la oxidacion del amonio con un rendimiento (YNO3 ) de 0.97±0.03 g N-NO−3g/g N-NH+
4 consumido. A 200 y 400 mg C-pOHBO/L, YNO3 disminuyo a 0.78 ± 0.05 y nitrito fue detectado (YNO2 = 0.04 ± 0.01g N-NO−2 /g N-NH+
4 consumido). El p-hidroxibenzoato (pOHBT)) se detecto como producto de la oxidacion del pOHBO. ElpOHBT se acumulo significativamente en los primeros ciclos de operacion, pero posteriormente fue completamente consumidoy no se detecto ningun intermediario aromatico. A valores de relacion C/N bajos (0.25-4), se mantuvo un proceso respiratorionitrificante desasimilativo (YBM = 0.03 ± 0.01 g N-biomasa/g N-NH+
4 consumido). Estos resultados muestran que los reactoresSBR nitrificantes pueden ser exitosamente utilizados para la eliminacion simultanea de amonio y p-hidroxibenzaldehido en unsolo reactor. Esta informacion puede ser util para el tratamiento de aguas residuales industriales contaminadas por nitrogeno ycompuestos fenolicos recalcitrantes.
Palabras clave: amonio, oxidacion biologica, p-hidroxibenzaldehido, nitrificacion, reactor de lotes secuenciados.
∗Corresponding auhor. E-mail: [email protected]
Publicado por la Academia Mexicana de Investigacion y Docencia en Ingenierıa Quımica A.C. 97
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Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) 97-104Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) XXX-XXX
1 Introduction38
There are several industries that can generate39
effluents containing high concentrations of ammonium40
and phenolic compounds (petrochemical, chemical,41
steel manufacturing, resin producing industries,42
among others) (Olmos et al., 2004). Phenolic43
compounds (phenol, cresols, chlorophenols, etc.)44
are toxic, and might be carcinogenic, mutagenic45
and teratogenic at high concentrations (Autenrieth46
et al., 1991). Nitrogen pollution by ammonium is47
linked to ecological (eutrophication, acidification),48
toxicological and economical impacts (Arredondo-49
Figueroa et al., 2007; Cervantes, 2009).50
Biological nitrification and denitrification51
processes are considered economically feasible52
technologies for nitrogen removal from wastewaters.53
Nitrification is the biological oxidation of ammonium54
(NH+4 ) via nitrite (NO−2 ) to nitrate (NO−3 ), and55
denitrification is the biological reduction of nitrate56
to nitrogen gas (N2). Recently, nitrifying processes57
have been proposed as novel alternative technologies58
for the simultaneous removal of ammonium and59
phenolic pollutants from industrial wastewaters60
(Beristain-Cardoso et al., 2011; Silva et al., 2011).61
Several nitrifying consortia have been reported62
to oxidize simultaneously ammonium and various63
phenolic compounds, being in some cases nitrate64
and carbon dioxide the major products (Yamaghisi65
et al., 2001; Amor et al., 2005; Vazquez et66
al., 2006; Texier and Gomez, 2007; Silva et al.,67
2009; Martınez-Hernandez et al., 2011). These68
results might be useful for using nitrifying reactors69
for the simultaneous removal of ammonium and70
phenolic compounds in one step from wastewaters71
of chemical complexity. There is no work reporting72
the simultaneous oxidation of p-hydroxybenzaldehyde73
(pOHBD) and ammonium in nitrifying reactors.74
pOHBD is a phenolic compound used in the chemistry,75
medicine and pharmaceutical industries and one76
of the intermediates from the p-cresol oxidation77
pathway. p-Cresol oxidation follows the same78
initial pathway under different aerobic and anaerobic79
conditions, consisting of the transient and sequential80
formation of p-hydroxybenzylalcohol, pOHBD, and81
p-hydroxybenzoate (pOHBT) (Haggblom et al.,82
1990). Preliminary results from batch experiments83
suggested that pOHBD oxidation would be the84
limiting step in p-cresol mineralization by a nitrifying85
consortium (Silva et al., 2009). However, more studies86
in biological reactors are necessary to evaluate the87
feasibility of using nitrifying sludge to remove both88
ammonium and pOHBD in a sole bioreactor.89
In recent years, conventional suspended-growth90
activated sludge system has been replaced by cost-91
effective and high-efficiency sequencing batch reactor92
(SBR), particularly for biological nutrient removal93
(Singh and Srivastava, 2011). SBR has proven94
to be a viable alternative to the continuous-flow95
systems for nitrogen removal through nitrification96
and denitrification biological processes (Puig et97
al., 2004). There is a need to improve the98
overall performance of the SBRs treating wastewaters99
of chemical complexity. The use of nitrifying100
SBRs for simultaneous removal of ammonium and101
carbonaceous compounds could be very attractive for102
wastewater treatment.103
In this study, a nitrifying SBR was used to104
oxidize simultaneously ammonium and pOHBD. The105
nitrification performance in the SBR and capability106
of the microbial sludge to remove pOHBD were107
evaluated at different initial concentrations of pOHBD108
throughout the operation cycles. Mass balances of109
both nitrogen and carbon were established, while110
efficiencies (ammonium and pOHBD consumption)111
and yields (nitrite, nitrate, and biomass production)112
were used as response variables of the respiratory113
processes.114
2 Materials and methods115
2.1 Inoculum116
The sludge used for inoculating the SBR was117
obtained from a continuous stirred tank reactor118
(CSTR) operated at steady-state nitrification. The119
composition of the medium used for the CSTR was120
(g/L): (NH4)2SO4 (1.73), NH4Cl (1.40), KH2PO4121
(2.73), MgSO4 (0.60), NaCl (1.0), NaHCO3 (9.30) and122
CaCl2 (0.05). The CSTR was continuously aerated123
and operated at 200 rpm, 30◦C ± 3, pH of 7.8 ± 0.3 and124
a hydraulic retention time of 3.5 d. At a NH+4 loading125
rate of 116 ± 9 mg N/L.d, the complete oxidation126
of ammonium (99.0 ± 1.6% of removal efficiency)127
into nitrate (yield of 0.90 ± 0.03 g NO−3 -N/g NH+4 -N128
consumed) was obtained. There was no accumulation129
of nitrite and ammonium in the continuous reactor.130
These results confirmed that nitrification in steady-131
state was achieved in the CSTR and the stabilized132
nitrifying sludge could be used as inoculum for the133
SBR.134
2 www.rmiq.org
Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) XXX-XXX
1 Introduction38
There are several industries that can generate39
effluents containing high concentrations of ammonium40
and phenolic compounds (petrochemical, chemical,41
steel manufacturing, resin producing industries,42
among others) (Olmos et al., 2004). Phenolic43
compounds (phenol, cresols, chlorophenols, etc.)44
are toxic, and might be carcinogenic, mutagenic45
and teratogenic at high concentrations (Autenrieth46
et al., 1991). Nitrogen pollution by ammonium is47
linked to ecological (eutrophication, acidification),48
toxicological and economical impacts (Arredondo-49
Figueroa et al., 2007; Cervantes, 2009).50
Biological nitrification and denitrification51
processes are considered economically feasible52
technologies for nitrogen removal from wastewaters.53
Nitrification is the biological oxidation of ammonium54
(NH+4 ) via nitrite (NO−2 ) to nitrate (NO−3 ), and55
denitrification is the biological reduction of nitrate56
to nitrogen gas (N2). Recently, nitrifying processes57
have been proposed as novel alternative technologies58
for the simultaneous removal of ammonium and59
phenolic pollutants from industrial wastewaters60
(Beristain-Cardoso et al., 2011; Silva et al., 2011).61
Several nitrifying consortia have been reported62
to oxidize simultaneously ammonium and various63
phenolic compounds, being in some cases nitrate64
and carbon dioxide the major products (Yamaghisi65
et al., 2001; Amor et al., 2005; Vazquez et66
al., 2006; Texier and Gomez, 2007; Silva et al.,67
2009; Martınez-Hernandez et al., 2011). These68
results might be useful for using nitrifying reactors69
for the simultaneous removal of ammonium and70
phenolic compounds in one step from wastewaters71
of chemical complexity. There is no work reporting72
the simultaneous oxidation of p-hydroxybenzaldehyde73
(pOHBD) and ammonium in nitrifying reactors.74
pOHBD is a phenolic compound used in the chemistry,75
medicine and pharmaceutical industries and one76
of the intermediates from the p-cresol oxidation77
pathway. p-Cresol oxidation follows the same78
initial pathway under different aerobic and anaerobic79
conditions, consisting of the transient and sequential80
formation of p-hydroxybenzylalcohol, pOHBD, and81
p-hydroxybenzoate (pOHBT) (Haggblom et al.,82
1990). Preliminary results from batch experiments83
suggested that pOHBD oxidation would be the84
limiting step in p-cresol mineralization by a nitrifying85
consortium (Silva et al., 2009). However, more studies86
in biological reactors are necessary to evaluate the87
feasibility of using nitrifying sludge to remove both88
ammonium and pOHBD in a sole bioreactor.89
In recent years, conventional suspended-growth90
activated sludge system has been replaced by cost-91
effective and high-efficiency sequencing batch reactor92
(SBR), particularly for biological nutrient removal93
(Singh and Srivastava, 2011). SBR has proven94
to be a viable alternative to the continuous-flow95
systems for nitrogen removal through nitrification96
and denitrification biological processes (Puig et97
al., 2004). There is a need to improve the98
overall performance of the SBRs treating wastewaters99
of chemical complexity. The use of nitrifying100
SBRs for simultaneous removal of ammonium and101
carbonaceous compounds could be very attractive for102
wastewater treatment.103
In this study, a nitrifying SBR was used to104
oxidize simultaneously ammonium and pOHBD. The105
nitrification performance in the SBR and capability106
of the microbial sludge to remove pOHBD were107
evaluated at different initial concentrations of pOHBD108
throughout the operation cycles. Mass balances of109
both nitrogen and carbon were established, while110
efficiencies (ammonium and pOHBD consumption)111
and yields (nitrite, nitrate, and biomass production)112
were used as response variables of the respiratory113
processes.114
2 Materials and methods115
2.1 Inoculum116
The sludge used for inoculating the SBR was117
obtained from a continuous stirred tank reactor118
(CSTR) operated at steady-state nitrification. The119
composition of the medium used for the CSTR was120
(g/L): (NH4)2SO4 (1.73), NH4Cl (1.40), KH2PO4121
(2.73), MgSO4 (0.60), NaCl (1.0), NaHCO3 (9.30) and122
CaCl2 (0.05). The CSTR was continuously aerated123
and operated at 200 rpm, 30◦C ± 3, pH of 7.8 ± 0.3 and124
a hydraulic retention time of 3.5 d. At a NH+4 loading125
rate of 116 ± 9 mg N/L.d, the complete oxidation126
of ammonium (99.0 ± 1.6% of removal efficiency)127
into nitrate (yield of 0.90 ± 0.03 g NO−3 -N/g NH+4 -N128
consumed) was obtained. There was no accumulation129
of nitrite and ammonium in the continuous reactor.130
These results confirmed that nitrification in steady-131
state was achieved in the CSTR and the stabilized132
nitrifying sludge could be used as inoculum for the133
SBR.134
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Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) 97-104Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) XXX-XXX
2.2 Reactor setup and operation135
A 2-L SBR was inoculated with 0.7 ± 0.1 g volatile136
suspended solids (VSS)/L of sludge previously137
stabilized in the CSTR. The operating conditions used138
for the SBR are presented in Table 1. Each 12 h139
cycle consisted of 10 min influent addition, 11 h140
aerated reaction, 30 min settling and 20 min effluent141
withdrawal. The hydraulic retention time was 0.55142
d and the volumetric exchange ratio of liquid was143
90%. The chemical composition of the basal medium144
was (g/L): (NH4)2SO4 (0.43), NH4Cl (0.36), KH2PO4145
(2.70), K2HPO4 (1.80), MgSO4 (0.40), NaCl (0.40),146
NaHCO3 (3.40) and CaCl2 (0.03). At the beginning147
of each cycle, the initial NH+4 concentration was 101148
± 3 mg N/L. NaHCO3 was used both as pH buffer149
and as carbon source. The reactor was operated at150
ambient temperature. Firstly, the SBR was operated151
without pOHBD feeding as control test to evaluate the152
nitrifying respiratory process under the experimental153
conditions used. After 70 cycles, pOHBD was154
added into the reactor at initial concentrations ranging155
from 25 to 400 mg C/L (50 to 800 mg pOHBD-156
C/L.d). According to the initial NH+4 -N and pOHBD-157
C concentrations, the C/N ratio varied between 0.25158
and 4. Samples were taken periodically in the159
influent and effluent of the SBR, filtered (0.45 µm),160
and analyzed for ammonium, nitrite, nitrate, pOHBD161
and pOHBT. Microbial performance was evaluated162
in terms of consumption efficiency (E, %, (g of N163
or C consumed/g of N or C fed) × 100) and yield164
(Y, g of N or C produced/g of N or C consumed).165
Additionally, mass balance was established for both166
N and C compounds.167
2.3 Analytical methods168
Ammonium nitrogen was analyzed by a selective169
electrode (Phoenix Electrode Co., USA). Nitrite,170
nitrate, pOHBD, and pOHBT concentrations were171
determined by HPLC as previously described by172
Silva et al. (2009). The volatile suspended solids173
(VSS) were determined according to standard methods174
(APHA, 1998). Lowry’s method was employed to175
measure microbial protein concentration (Lowry et al.,176
1951). In order to express the biomass concentration177
as biomass-N and biomass-C in the mass balances,178
it was considered that 16% of microbial protein is179
nitrogen and 50% of biomass is carbon (Bailey and180
Ollis, 1986). pH and dissolved oxygen concentrations181
were determined by selective electrodes. Analytical182
methods had a variation coefficient of less than 10%.183
Table 1. Operating conditions of thenitrifying sequencing batch reactor.
Conditions Value
Working volume 2 LCycles time 12 h
VSS 0.7 ± 0.1 g/LpH 8.1 ± 0.4
Dissolved oxygen 5.3 ± 0.1 mg/LTemperature 25 ± 5◦C
Agitation 225 rpmAeration flow 2 vvm
vvm: volumes of air per volume of liquidper minute
184
3 Results and discussion185
3.1 Nitrifying performance of the SBR fed186
with p-hydroxybenzaldehyde187
Nitrifying performance of the SBR fed at different188
initial pOHBD concentrations (25-400 mg C/L) is189
presented in Fig. 1 and Table 2. In the first190
period (cycles 1 to 70) when the reactor was fed191
with ammonium alone, the ammonium consumption192
efficiency was 99.5 ± 0.7% and the main product193
was nitrate with a yield of 0.96 ± 0.07 g NO−3 -194
N/g NH+4 -N consumed. These results indicated that195
the sludge showed a stable nitrifying activity under196
the experimental conditions used in the SBR. At all197
initial pOHBD concentrations tested (25-400 mg C/L),198
ammonium was totally consumed with an average199
efficiency of 99.2 ± 1.5%. At pOHBD concentrations200
ranging from 25 to 100 mg C/L, the main nitrogenous201
product of ammonium oxidation was nitrate with a202
YNO3 of 0.97 ± 0.03 g NO−3 -N/g NH+4 -N consumed.203
There was no nitrite accumulation in the SBR. At204
a pOHBD concentration of 200 mg C/L, nitrate205
formation tended to decrease. At 400 mg pOHBD-206
C/L, the YNO3 value dropped to 0.83 ± 0.10 g NO−3 -207
N/g NH+4 -N consumed while nitrite was detected in208
the culture (YNO2 = 0.04 ± 0.01 g NO−2 -N/g NH+4 -N209
consumed). In all cases, except at 200 mg pOHBD-210
C/L, the recovery percentage of nitrogen products211
was higher than 90% from the ammonium initially212
added. Considering a variation coefficient of 10% in213
our results due to variations in analytical methods, this214
result is satisfactory. However, at 200 mg pOHBD-215
C/L, the recovery percentage decreased to 76%. In this216
period, an increase in the pH value was observed in217
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Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) XXX-XXX
2.2 Reactor setup and operation135
A 2-L SBR was inoculated with 0.7 ± 0.1 g volatile136
suspended solids (VSS)/L of sludge previously137
stabilized in the CSTR. The operating conditions used138
for the SBR are presented in Table 1. Each 12 h139
cycle consisted of 10 min influent addition, 11 h140
aerated reaction, 30 min settling and 20 min effluent141
withdrawal. The hydraulic retention time was 0.55142
d and the volumetric exchange ratio of liquid was143
90%. The chemical composition of the basal medium144
was (g/L): (NH4)2SO4 (0.43), NH4Cl (0.36), KH2PO4145
(2.70), K2HPO4 (1.80), MgSO4 (0.40), NaCl (0.40),146
NaHCO3 (3.40) and CaCl2 (0.03). At the beginning147
of each cycle, the initial NH+4 concentration was 101148
± 3 mg N/L. NaHCO3 was used both as pH buffer149
and as carbon source. The reactor was operated at150
ambient temperature. Firstly, the SBR was operated151
without pOHBD feeding as control test to evaluate the152
nitrifying respiratory process under the experimental153
conditions used. After 70 cycles, pOHBD was154
added into the reactor at initial concentrations ranging155
from 25 to 400 mg C/L (50 to 800 mg pOHBD-156
C/L.d). According to the initial NH+4 -N and pOHBD-157
C concentrations, the C/N ratio varied between 0.25158
and 4. Samples were taken periodically in the159
influent and effluent of the SBR, filtered (0.45 µm),160
and analyzed for ammonium, nitrite, nitrate, pOHBD161
and pOHBT. Microbial performance was evaluated162
in terms of consumption efficiency (E, %, (g of N163
or C consumed/g of N or C fed) × 100) and yield164
(Y, g of N or C produced/g of N or C consumed).165
Additionally, mass balance was established for both166
N and C compounds.167
2.3 Analytical methods168
Ammonium nitrogen was analyzed by a selective169
electrode (Phoenix Electrode Co., USA). Nitrite,170
nitrate, pOHBD, and pOHBT concentrations were171
determined by HPLC as previously described by172
Silva et al. (2009). The volatile suspended solids173
(VSS) were determined according to standard methods174
(APHA, 1998). Lowry’s method was employed to175
measure microbial protein concentration (Lowry et al.,176
1951). In order to express the biomass concentration177
as biomass-N and biomass-C in the mass balances,178
it was considered that 16% of microbial protein is179
nitrogen and 50% of biomass is carbon (Bailey and180
Ollis, 1986). pH and dissolved oxygen concentrations181
were determined by selective electrodes. Analytical182
methods had a variation coefficient of less than 10%.183
Table 1. Operating conditions of thenitrifying sequencing batch reactor.
Conditions Value
Working volume 2 LCycles time 12 h
VSS 0.7 ± 0.1 g/LpH 8.1 ± 0.4
Dissolved oxygen 5.3 ± 0.1 mg/LTemperature 25 ± 5◦C
Agitation 225 rpmAeration flow 2 vvm
vvm: volumes of air per volume of liquidper minute
184
3 Results and discussion185
3.1 Nitrifying performance of the SBR fed186
with p-hydroxybenzaldehyde187
Nitrifying performance of the SBR fed at different188
initial pOHBD concentrations (25-400 mg C/L) is189
presented in Fig. 1 and Table 2. In the first190
period (cycles 1 to 70) when the reactor was fed191
with ammonium alone, the ammonium consumption192
efficiency was 99.5 ± 0.7% and the main product193
was nitrate with a yield of 0.96 ± 0.07 g NO−3 -194
N/g NH+4 -N consumed. These results indicated that195
the sludge showed a stable nitrifying activity under196
the experimental conditions used in the SBR. At all197
initial pOHBD concentrations tested (25-400 mg C/L),198
ammonium was totally consumed with an average199
efficiency of 99.2 ± 1.5%. At pOHBD concentrations200
ranging from 25 to 100 mg C/L, the main nitrogenous201
product of ammonium oxidation was nitrate with a202
YNO3 of 0.97 ± 0.03 g NO−3 -N/g NH+4 -N consumed.203
There was no nitrite accumulation in the SBR. At204
a pOHBD concentration of 200 mg C/L, nitrate205
formation tended to decrease. At 400 mg pOHBD-206
C/L, the YNO3 value dropped to 0.83 ± 0.10 g NO−3 -207
N/g NH+4 -N consumed while nitrite was detected in208
the culture (YNO2 = 0.04 ± 0.01 g NO−2 -N/g NH+4 -N209
consumed). In all cases, except at 200 mg pOHBD-210
C/L, the recovery percentage of nitrogen products211
was higher than 90% from the ammonium initially212
added. Considering a variation coefficient of 10% in213
our results due to variations in analytical methods, this214
result is satisfactory. However, at 200 mg pOHBD-215
C/L, the recovery percentage decreased to 76%. In this216
period, an increase in the pH value was observed in217
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Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) 97-104Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) XXX-XXX
the SBR, which might provoke nitrogen volatilization218
as NH3. As soon as the pH value was newly219
controlled in the system (at 400 mg pOHBD-C/L),220
the recovery percentage increased to 90%, showing221
that the main products of ammonium oxidation were222
detected as nitrite, nitrate and biomass. These results223
suggest that pOHBD at higher concentrations than224
100 mg C/L might alter the nitrifying performance225
of the SBR as nitrate production tended to diminish226
and nitrite to accumulate. As shown in Table 2,227
biomass formation increased with the initial pOHBD228
concentrations, indicating an increase in nitrogen229
assimilation. However, the maximum YBM value was230
0.03 ± 0.01 g biomass-N/g NH+4 -N consumed. This231
shows that only 3% of the ammonium consumed was232
used for biosynthesis and the nitrifying process kept233
essentially dissimilatory. The addition of organic234
matter in bioreactors generally causes an increase235
in the microbial growth and alters the nitrifying236
performance due to competition for ammonium and237
dissolved oxygen between nitrifiers and heterotrophs238
in the sludge (Hanaki et al., 1990). However, in our239
study, the pOHBD-C/N ratio was maintained at low240
values (0.25 - 4.00) and biomass growth was limited.241
The experimental results demonstrated that242
nitrification can successfully occur at an initial243
pOHBD concentration up to 100 mg C/L,244
corresponding to a pOHBD loading rate of 200 mg245
C/L.d. Benzaldehydes are known for having an246
antibacterial activity and it has been suggested that247
they act on the cell surface by reacting with sulfhydryl248
groups (Ramos-Nino et al., 1998). Results from249
the study of Silva et al. (2009) performed in batch250
experiments indicated that pOHBD could be the main251
intermediate from p-cresol oxidation that would be252
responsible for nitrification inhibition. The authors253
observed the inhibitory effect through a decrease in254
the nitrification specific rates. This suggests that in the255
present study, the nitrification process might have been256
slower in the SBR due to the pOHBD inhibitory effect257
but the 12 h cycles were sufficiently longer to reach258
high values for ENH4 and YNO3 . At higher pOHBD259
concentrations than 100 mg C/L, the inhibitory effect260
of the aromatic compound might induce a decrease261
in nitrate formation and a nitrite accumulation in262
the reactor. However, further research is needed to263
understand better how pOHBD affects nitrification264
processes, including studies with axenic cultures and265
nitrifying consortia, in batch cultures as in biological266
reactors. Recently, Silva et al. (2011) observed in267
batch assays that pOHBD would not be inhibitory for268
nitrification when the sludge was previously fed with269
p-cresol, suggesting that the previous exposure of the270
sludge to a phenolic compound might contribute to271
a better tolerance to pOHBD. In the present work,272
the use of a SBR as bioreactor where there is a273
repetitive exposure of the sludge to the phenolic274
compound might contribute to a higher tolerance of275
the consortium to the toxic throughout the cycles.276
277
Fig. 1. Nitrifying performance of the SBR fed with p-hydroxybenzaldehyde (p-OHBD) at different initial278
concentrations (25-400 mg C/L).279
4 www.rmiq.org
Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) XXX-XXX
the SBR, which might provoke nitrogen volatilization218
as NH3. As soon as the pH value was newly219
controlled in the system (at 400 mg pOHBD-C/L),220
the recovery percentage increased to 90%, showing221
that the main products of ammonium oxidation were222
detected as nitrite, nitrate and biomass. These results223
suggest that pOHBD at higher concentrations than224
100 mg C/L might alter the nitrifying performance225
of the SBR as nitrate production tended to diminish226
and nitrite to accumulate. As shown in Table 2,227
biomass formation increased with the initial pOHBD228
concentrations, indicating an increase in nitrogen229
assimilation. However, the maximum YBM value was230
0.03 ± 0.01 g biomass-N/g NH+4 -N consumed. This231
shows that only 3% of the ammonium consumed was232
used for biosynthesis and the nitrifying process kept233
essentially dissimilatory. The addition of organic234
matter in bioreactors generally causes an increase235
in the microbial growth and alters the nitrifying236
performance due to competition for ammonium and237
dissolved oxygen between nitrifiers and heterotrophs238
in the sludge (Hanaki et al., 1990). However, in our239
study, the pOHBD-C/N ratio was maintained at low240
values (0.25 - 4.00) and biomass growth was limited.241
The experimental results demonstrated that242
nitrification can successfully occur at an initial243
pOHBD concentration up to 100 mg C/L,244
corresponding to a pOHBD loading rate of 200 mg245
C/L.d. Benzaldehydes are known for having an246
antibacterial activity and it has been suggested that247
they act on the cell surface by reacting with sulfhydryl248
groups (Ramos-Nino et al., 1998). Results from249
the study of Silva et al. (2009) performed in batch250
experiments indicated that pOHBD could be the main251
intermediate from p-cresol oxidation that would be252
responsible for nitrification inhibition. The authors253
observed the inhibitory effect through a decrease in254
the nitrification specific rates. This suggests that in the255
present study, the nitrification process might have been256
slower in the SBR due to the pOHBD inhibitory effect257
but the 12 h cycles were sufficiently longer to reach258
high values for ENH4 and YNO3 . At higher pOHBD259
concentrations than 100 mg C/L, the inhibitory effect260
of the aromatic compound might induce a decrease261
in nitrate formation and a nitrite accumulation in262
the reactor. However, further research is needed to263
understand better how pOHBD affects nitrification264
processes, including studies with axenic cultures and265
nitrifying consortia, in batch cultures as in biological266
reactors. Recently, Silva et al. (2011) observed in267
batch assays that pOHBD would not be inhibitory for268
nitrification when the sludge was previously fed with269
p-cresol, suggesting that the previous exposure of the270
sludge to a phenolic compound might contribute to271
a better tolerance to pOHBD. In the present work,272
the use of a SBR as bioreactor where there is a273
repetitive exposure of the sludge to the phenolic274
compound might contribute to a higher tolerance of275
the consortium to the toxic throughout the cycles.276
277
Fig. 1. Nitrifying performance of the SBR fed with p-hydroxybenzaldehyde (p-OHBD) at different initial278
concentrations (25-400 mg C/L).279
4 www.rmiq.org
Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) XXX-XXX
the SBR, which might provoke nitrogen volatilization218
as NH3. As soon as the pH value was newly219
controlled in the system (at 400 mg pOHBD-C/L),220
the recovery percentage increased to 90%, showing221
that the main products of ammonium oxidation were222
detected as nitrite, nitrate and biomass. These results223
suggest that pOHBD at higher concentrations than224
100 mg C/L might alter the nitrifying performance225
of the SBR as nitrate production tended to diminish226
and nitrite to accumulate. As shown in Table 2,227
biomass formation increased with the initial pOHBD228
concentrations, indicating an increase in nitrogen229
assimilation. However, the maximum YBM value was230
0.03 ± 0.01 g biomass-N/g NH+4 -N consumed. This231
shows that only 3% of the ammonium consumed was232
used for biosynthesis and the nitrifying process kept233
essentially dissimilatory. The addition of organic234
matter in bioreactors generally causes an increase235
in the microbial growth and alters the nitrifying236
performance due to competition for ammonium and237
dissolved oxygen between nitrifiers and heterotrophs238
in the sludge (Hanaki et al., 1990). However, in our239
study, the pOHBD-C/N ratio was maintained at low240
values (0.25 - 4.00) and biomass growth was limited.241
The experimental results demonstrated that242
nitrification can successfully occur at an initial243
pOHBD concentration up to 100 mg C/L,244
corresponding to a pOHBD loading rate of 200 mg245
C/L.d. Benzaldehydes are known for having an246
antibacterial activity and it has been suggested that247
they act on the cell surface by reacting with sulfhydryl248
groups (Ramos-Nino et al., 1998). Results from249
the study of Silva et al. (2009) performed in batch250
experiments indicated that pOHBD could be the main251
intermediate from p-cresol oxidation that would be252
responsible for nitrification inhibition. The authors253
observed the inhibitory effect through a decrease in254
the nitrification specific rates. This suggests that in the255
present study, the nitrification process might have been256
slower in the SBR due to the pOHBD inhibitory effect257
but the 12 h cycles were sufficiently longer to reach258
high values for ENH4 and YNO3 . At higher pOHBD259
concentrations than 100 mg C/L, the inhibitory effect260
of the aromatic compound might induce a decrease261
in nitrate formation and a nitrite accumulation in262
the reactor. However, further research is needed to263
understand better how pOHBD affects nitrification264
processes, including studies with axenic cultures and265
nitrifying consortia, in batch cultures as in biological266
reactors. Recently, Silva et al. (2011) observed in267
batch assays that pOHBD would not be inhibitory for268
nitrification when the sludge was previously fed with269
p-cresol, suggesting that the previous exposure of the270
sludge to a phenolic compound might contribute to271
a better tolerance to pOHBD. In the present work,272
the use of a SBR as bioreactor where there is a273
repetitive exposure of the sludge to the phenolic274
compound might contribute to a higher tolerance of275
the consortium to the toxic throughout the cycles.276
277
Fig. 1. Nitrifying performance of the SBR fed with p-hydroxybenzaldehyde (p-OHBD) at different initial278
concentrations (25-400 mg C/L).279
4 www.rmiq.org100 www.rmiq.org
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Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) 97-104Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) XXX-XXX
Table 2. Nitrogen mass balance in the nitrifying SBR fed withp-hydroxybenzaldehyde.
Added Input-N (mg/L) Output-N (mg/L)pOHBD NH+
4 -N NH+4 -N NO−2 -N NO−3 -N Biomass-N
(mg C/L)
0 101.1 ± 0.6 0.5 ± 0.7 0 96.7 ± 6.9 0.4 ± 0.125 103.0 ± 0.1 0.2 ± 0.2 0 95.7 ± 5.3 0.4 ± 0.150 98.2 ± 0.1 0.2 ± 0.3 0 98.6 ± 5.2 0.9 ± 0.1
100 96.7 ± 0.1 0.1 ± 0.1 0 93.6 ± 5.4 1.6 ± 0.1200 106.4 ± 0.2 0.0 ± 0.0 0 77.5 ± 7.3 3.1 ± 0.1400 101.5 ± 0.1 4.0 ± 1.8 3.7 ± 1.2 81.3 ± 9.9 2.1 ± 0.1
280
281
Fig. 2. p-Hydroxybenzaldehyde (p-OHBD) consumption and p-hydroxybenzoate (p-OHBT) production in a282
nitrifying sequencing batch reactor.283
Bacteria can develop mechanisms to change284
membrane configuration and acquire a higher285
resistance to toxics such as benzaldehydes (van Schie286
and Young, 2000). Nonetheless, further works are287
required in order to understand this phenomenon.288
3.2 p-hydroxybenzaldehyde oxidation in289
the nitrifying SBR290
At all initial concentrations (25-400 mg C/L), pOHBD291
consumption was complete, resulting in an EpOHBD of292
100% (Fig. 2 and Table 3). It has been previously293
reported that in abiotic assays under conditions of294
aeration and agitation similar to those used in the295
present study, the lost of pOHBD by volatilization was296
negligible (Silva et al., 2011). p-Hydroxybenzoate297
(pOHBT) was detected as intermediate of pOHBD298
oxidation by the consortium. In the first cycles299
operated at 25 mg pOHBD-C/L (cycles 70 to 100),300
pOHBT was accumulated at 21.1 ± 1.9 mg C/L,301
corresponding to 85% of the pOHBD initially added.302
However, in the following SBR cycles, pOHBT was303
removed at efficiencies higher than 95%. It was304
also verified by HPLC that no aromatic compounds305
were accumulated in the culture. It has been306
previously observed in batch studies that pOHBD307
is a recalcitrant phenolic compound that shows low308
specific consumption rates under nitrifying conditions309
www.rmiq.org 5
Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) XXX-XXX
Table 2. Nitrogen mass balance in the nitrifying SBR fed withp-hydroxybenzaldehyde.
Added Input-N (mg/L) Output-N (mg/L)pOHBD NH+
4 -N NH+4 -N NO−2 -N NO−3 -N Biomass-N
(mg C/L)
0 101.1 ± 0.6 0.5 ± 0.7 0 96.7 ± 6.9 0.4 ± 0.125 103.0 ± 0.1 0.2 ± 0.2 0 95.7 ± 5.3 0.4 ± 0.150 98.2 ± 0.1 0.2 ± 0.3 0 98.6 ± 5.2 0.9 ± 0.1
100 96.7 ± 0.1 0.1 ± 0.1 0 93.6 ± 5.4 1.6 ± 0.1200 106.4 ± 0.2 0.0 ± 0.0 0 77.5 ± 7.3 3.1 ± 0.1400 101.5 ± 0.1 4.0 ± 1.8 3.7 ± 1.2 81.3 ± 9.9 2.1 ± 0.1
280
281
Fig. 2. p-Hydroxybenzaldehyde (p-OHBD) consumption and p-hydroxybenzoate (p-OHBT) production in a282
nitrifying sequencing batch reactor.283
Bacteria can develop mechanisms to change284
membrane configuration and acquire a higher285
resistance to toxics such as benzaldehydes (van Schie286
and Young, 2000). Nonetheless, further works are287
required in order to understand this phenomenon.288
3.2 p-hydroxybenzaldehyde oxidation in289
the nitrifying SBR290
At all initial concentrations (25-400 mg C/L), pOHBD291
consumption was complete, resulting in an EpOHBD of292
100% (Fig. 2 and Table 3). It has been previously293
reported that in abiotic assays under conditions of294
aeration and agitation similar to those used in the295
present study, the lost of pOHBD by volatilization was296
negligible (Silva et al., 2011). p-Hydroxybenzoate297
(pOHBT) was detected as intermediate of pOHBD298
oxidation by the consortium. In the first cycles299
operated at 25 mg pOHBD-C/L (cycles 70 to 100),300
pOHBT was accumulated at 21.1 ± 1.9 mg C/L,301
corresponding to 85% of the pOHBD initially added.302
However, in the following SBR cycles, pOHBT was303
removed at efficiencies higher than 95%. It was304
also verified by HPLC that no aromatic compounds305
were accumulated in the culture. It has been306
previously observed in batch studies that pOHBD307
is a recalcitrant phenolic compound that shows low308
specific consumption rates under nitrifying conditions309
www.rmiq.org 5
Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) XXX-XXX
Table 2. Nitrogen mass balance in the nitrifying SBR fed withp-hydroxybenzaldehyde.
Added Input-N (mg/L) Output-N (mg/L)pOHBD NH+
4 -N NH+4 -N NO−2 -N NO−3 -N Biomass-N
(mg C/L)
0 101.1 ± 0.6 0.5 ± 0.7 0 96.7 ± 6.9 0.4 ± 0.125 103.0 ± 0.1 0.2 ± 0.2 0 95.7 ± 5.3 0.4 ± 0.150 98.2 ± 0.1 0.2 ± 0.3 0 98.6 ± 5.2 0.9 ± 0.1
100 96.7 ± 0.1 0.1 ± 0.1 0 93.6 ± 5.4 1.6 ± 0.1200 106.4 ± 0.2 0.0 ± 0.0 0 77.5 ± 7.3 3.1 ± 0.1400 101.5 ± 0.1 4.0 ± 1.8 3.7 ± 1.2 81.3 ± 9.9 2.1 ± 0.1
280
281
Fig. 2. p-Hydroxybenzaldehyde (p-OHBD) consumption and p-hydroxybenzoate (p-OHBT) production in a282
nitrifying sequencing batch reactor.283
Bacteria can develop mechanisms to change284
membrane configuration and acquire a higher285
resistance to toxics such as benzaldehydes (van Schie286
and Young, 2000). Nonetheless, further works are287
required in order to understand this phenomenon.288
3.2 p-hydroxybenzaldehyde oxidation in289
the nitrifying SBR290
At all initial concentrations (25-400 mg C/L), pOHBD291
consumption was complete, resulting in an EpOHBD of292
100% (Fig. 2 and Table 3). It has been previously293
reported that in abiotic assays under conditions of294
aeration and agitation similar to those used in the295
present study, the lost of pOHBD by volatilization was296
negligible (Silva et al., 2011). p-Hydroxybenzoate297
(pOHBT) was detected as intermediate of pOHBD298
oxidation by the consortium. In the first cycles299
operated at 25 mg pOHBD-C/L (cycles 70 to 100),300
pOHBT was accumulated at 21.1 ± 1.9 mg C/L,301
corresponding to 85% of the pOHBD initially added.302
However, in the following SBR cycles, pOHBT was303
removed at efficiencies higher than 95%. It was304
also verified by HPLC that no aromatic compounds305
were accumulated in the culture. It has been306
previously observed in batch studies that pOHBD307
is a recalcitrant phenolic compound that shows low308
specific consumption rates under nitrifying conditions309
www.rmiq.org 5www.rmiq.org 101
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Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) 97-104
Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) XXX-XXX
Table 3. Carbon mass balance in the nitrifying SBR fed withp-hydroxybenzaldehyde.
Added Input-C (mg/L) Output-C (mg/L)pOHBD pOHBD pOHBD pOHBT Biomass-C(mg C/L)
0 0.0 ± 0.0 0.0 ± 0.0 0.0 ±0.0 0.0 ± 0.025 24.7 ± 1.3 0.0 ± 0.0 21.1 ± 1.9 2.0 ± 0.150 56.1 ± 0.9 0.0 ± 0.0 1.7 ± 1.6 4.1 ± 0.3
100 100.0 ± 1.9 0.0 ± 0.0 1.0 ± 0.2 7.9 ± 0.5200 195.6 ± 2.2 0.0 ± 0.0 8.7 ± 0.2 15.0 ± 0.3400 402.5 ± 5.8 0.0 ± 0.0 0.7 ± 2.5 16.3 ± 0.3
310
(Silva et al., 2009, 2011). In our work, it was311
shown that under the experimental conditions used312
in the SBR, the consortium was able to oxidize313
pOHBD at a maximum concentration of 400 mg C/L,314
corresponding to a loading rate of 800 mg C/L.d. In315
spite of the recalcitrance of pOHBD, the SBR could316
be a good technology for pOHBD treatment. This317
type of reactor has previously been shown to allow the318
metabolic adaptation of sludge through the operation319
cycles, resulting in higher specific consumption rates320
of recalcitrant pollutants (Zhuang et al., 2005). As321
it can be seen in Table 3, carbon assimilation for322
biomass synthesis increased with the initial pOHBD323
concentration. However, in terms of biomass yield,324
it was found that the process was dissimilatory as325
the maximum YBM was only of 0.08 biomass-C/g326
pOHBD-C consumed. In the study of Eiroa et al.327
(2005), the simultaneous removal of formaldehyde328
and ammonium in a lab-scale activated sludge unit329
was investigated. High removal efficiencies were330
obtained for both ammonium and formaldehyde (99.9331
and 99.5%, respectively). However, at formaldehyde332
loading rates higher than 0.48 g COD/L.d, the nitrate333
concentration in the effluent decreased. According to334
the authors, this decrease can be basically attributed335
to denitrification and ammonium assimilation by the336
heterothophs. However, the authors did not present337
data of N2 production or biomass yield. In the present338
study, the low value for YBM indicated that growth of339
the heterotrophic population of the consortium was340
limited under the experimental conditions used in341
the SBR (low C/N ratio, lithoautotrophic medium,342
physiologically stable nitrifying inoculum).343
Conclusions344
In a SBR fed with ammonium at 100 mg N/L (200345
mg N/L.d) and pOHBD at concentrations between346
25 and 400 mg C/L (50 to 800 mg C/L.d), the347
nitrifying sludge achieved total removal of ammonium348
and pOHBD with efficiencies of 99.2 ± 1.5% and349
100 ± 1%, respectively. At pOHBD concentrations350
lower than 100 mg C/L, nitrification was not affected351
and nitrate was the main end product of the nitrifying352
pathway. Nitrite was not accumulated and the biomass353
formation kept very low. These results show that354
nitrifying SBR could be a good alternative for the355
simultaneous removal of ammonium and recalcitrant356
phenolic compounds from wastewaters. Additionally,357
results showed a novel and interesting aspect of358
using nitrifying consortia physiologically stable in359
wastewater treatment as they might perform various360
biological respiratory processes in a unique reactor for361
oxidizing ammonium and organic pollutants.362
References363
Amor, L., Eiroa, M., Kennes, C. and Veiga, M.C.364
(2005). Phenol biodegradation and its effect on365
the nitrification process. Water Research 39,366
2915-2920.367
APHA (1998). Standard Methods for the368
Examination of Water and Wastewater. 20th369
Edition, American Public Health Association370
(APHA), Washington.371
Arredondo-Figueroa, J.L., Ingle de la Mora, G.,372
Guerrero-Legarreta, I., Ponce-Palafox, J.T. and373
Barriga-Sosa, I. de los A. (2007). Ammonia and374
6 www.rmiq.org
Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) XXX-XXX
Table 3. Carbon mass balance in the nitrifying SBR fed withp-hydroxybenzaldehyde.
Added Input-C (mg/L) Output-C (mg/L)pOHBD pOHBD pOHBD pOHBT Biomass-C(mg C/L)
0 0.0 ± 0.0 0.0 ± 0.0 0.0 ±0.0 0.0 ± 0.025 24.7 ± 1.3 0.0 ± 0.0 21.1 ± 1.9 2.0 ± 0.150 56.1 ± 0.9 0.0 ± 0.0 1.7 ± 1.6 4.1 ± 0.3
100 100.0 ± 1.9 0.0 ± 0.0 1.0 ± 0.2 7.9 ± 0.5200 195.6 ± 2.2 0.0 ± 0.0 8.7 ± 0.2 15.0 ± 0.3400 402.5 ± 5.8 0.0 ± 0.0 0.7 ± 2.5 16.3 ± 0.3
310
(Silva et al., 2009, 2011). In our work, it was311
shown that under the experimental conditions used312
in the SBR, the consortium was able to oxidize313
pOHBD at a maximum concentration of 400 mg C/L,314
corresponding to a loading rate of 800 mg C/L.d. In315
spite of the recalcitrance of pOHBD, the SBR could316
be a good technology for pOHBD treatment. This317
type of reactor has previously been shown to allow the318
metabolic adaptation of sludge through the operation319
cycles, resulting in higher specific consumption rates320
of recalcitrant pollutants (Zhuang et al., 2005). As321
it can be seen in Table 3, carbon assimilation for322
biomass synthesis increased with the initial pOHBD323
concentration. However, in terms of biomass yield,324
it was found that the process was dissimilatory as325
the maximum YBM was only of 0.08 biomass-C/g326
pOHBD-C consumed. In the study of Eiroa et al.327
(2005), the simultaneous removal of formaldehyde328
and ammonium in a lab-scale activated sludge unit329
was investigated. High removal efficiencies were330
obtained for both ammonium and formaldehyde (99.9331
and 99.5%, respectively). However, at formaldehyde332
loading rates higher than 0.48 g COD/L.d, the nitrate333
concentration in the effluent decreased. According to334
the authors, this decrease can be basically attributed335
to denitrification and ammonium assimilation by the336
heterothophs. However, the authors did not present337
data of N2 production or biomass yield. In the present338
study, the low value for YBM indicated that growth of339
the heterotrophic population of the consortium was340
limited under the experimental conditions used in341
the SBR (low C/N ratio, lithoautotrophic medium,342
physiologically stable nitrifying inoculum).343
Conclusions344
In a SBR fed with ammonium at 100 mg N/L (200345
mg N/L.d) and pOHBD at concentrations between346
25 and 400 mg C/L (50 to 800 mg C/L.d), the347
nitrifying sludge achieved total removal of ammonium348
and pOHBD with efficiencies of 99.2 ± 1.5% and349
100 ± 1%, respectively. At pOHBD concentrations350
lower than 100 mg C/L, nitrification was not affected351
and nitrate was the main end product of the nitrifying352
pathway. Nitrite was not accumulated and the biomass353
formation kept very low. These results show that354
nitrifying SBR could be a good alternative for the355
simultaneous removal of ammonium and recalcitrant356
phenolic compounds from wastewaters. Additionally,357
results showed a novel and interesting aspect of358
using nitrifying consortia physiologically stable in359
wastewater treatment as they might perform various360
biological respiratory processes in a unique reactor for361
oxidizing ammonium and organic pollutants.362
References363
Amor, L., Eiroa, M., Kennes, C. and Veiga, M.C.364
(2005). Phenol biodegradation and its effect on365
the nitrification process. Water Research 39,366
2915-2920.367
APHA (1998). Standard Methods for the368
Examination of Water and Wastewater. 20th369
Edition, American Public Health Association370
(APHA), Washington.371
Arredondo-Figueroa, J.L., Ingle de la Mora, G.,372
Guerrero-Legarreta, I., Ponce-Palafox, J.T. and373
Barriga-Sosa, I. de los A. (2007). Ammonia and374
6 www.rmiq.org
Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) XXX-XXX
Table 3. Carbon mass balance in the nitrifying SBR fed withp-hydroxybenzaldehyde.
Added Input-C (mg/L) Output-C (mg/L)pOHBD pOHBD pOHBD pOHBT Biomass-C(mg C/L)
0 0.0 ± 0.0 0.0 ± 0.0 0.0 ±0.0 0.0 ± 0.025 24.7 ± 1.3 0.0 ± 0.0 21.1 ± 1.9 2.0 ± 0.150 56.1 ± 0.9 0.0 ± 0.0 1.7 ± 1.6 4.1 ± 0.3
100 100.0 ± 1.9 0.0 ± 0.0 1.0 ± 0.2 7.9 ± 0.5200 195.6 ± 2.2 0.0 ± 0.0 8.7 ± 0.2 15.0 ± 0.3400 402.5 ± 5.8 0.0 ± 0.0 0.7 ± 2.5 16.3 ± 0.3
310
(Silva et al., 2009, 2011). In our work, it was311
shown that under the experimental conditions used312
in the SBR, the consortium was able to oxidize313
pOHBD at a maximum concentration of 400 mg C/L,314
corresponding to a loading rate of 800 mg C/L.d. In315
spite of the recalcitrance of pOHBD, the SBR could316
be a good technology for pOHBD treatment. This317
type of reactor has previously been shown to allow the318
metabolic adaptation of sludge through the operation319
cycles, resulting in higher specific consumption rates320
of recalcitrant pollutants (Zhuang et al., 2005). As321
it can be seen in Table 3, carbon assimilation for322
biomass synthesis increased with the initial pOHBD323
concentration. However, in terms of biomass yield,324
it was found that the process was dissimilatory as325
the maximum YBM was only of 0.08 biomass-C/g326
pOHBD-C consumed. In the study of Eiroa et al.327
(2005), the simultaneous removal of formaldehyde328
and ammonium in a lab-scale activated sludge unit329
was investigated. High removal efficiencies were330
obtained for both ammonium and formaldehyde (99.9331
and 99.5%, respectively). However, at formaldehyde332
loading rates higher than 0.48 g COD/L.d, the nitrate333
concentration in the effluent decreased. According to334
the authors, this decrease can be basically attributed335
to denitrification and ammonium assimilation by the336
heterothophs. However, the authors did not present337
data of N2 production or biomass yield. In the present338
study, the low value for YBM indicated that growth of339
the heterotrophic population of the consortium was340
limited under the experimental conditions used in341
the SBR (low C/N ratio, lithoautotrophic medium,342
physiologically stable nitrifying inoculum).343
Conclusions344
In a SBR fed with ammonium at 100 mg N/L (200345
mg N/L.d) and pOHBD at concentrations between346
25 and 400 mg C/L (50 to 800 mg C/L.d), the347
nitrifying sludge achieved total removal of ammonium348
and pOHBD with efficiencies of 99.2 ± 1.5% and349
100 ± 1%, respectively. At pOHBD concentrations350
lower than 100 mg C/L, nitrification was not affected351
and nitrate was the main end product of the nitrifying352
pathway. Nitrite was not accumulated and the biomass353
formation kept very low. These results show that354
nitrifying SBR could be a good alternative for the355
simultaneous removal of ammonium and recalcitrant356
phenolic compounds from wastewaters. Additionally,357
results showed a novel and interesting aspect of358
using nitrifying consortia physiologically stable in359
wastewater treatment as they might perform various360
biological respiratory processes in a unique reactor for361
oxidizing ammonium and organic pollutants.362
References363
Amor, L., Eiroa, M., Kennes, C. and Veiga, M.C.364
(2005). Phenol biodegradation and its effect on365
the nitrification process. Water Research 39,366
2915-2920.367
APHA (1998). Standard Methods for the368
Examination of Water and Wastewater. 20th369
Edition, American Public Health Association370
(APHA), Washington.371
Arredondo-Figueroa, J.L., Ingle de la Mora, G.,372
Guerrero-Legarreta, I., Ponce-Palafox, J.T. and373
Barriga-Sosa, I. de los A. (2007). Ammonia and374
6 www.rmiq.org
102 www.rmiq.org
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Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) 97-104Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) XXX-XXX
nitrite removal rates in a closed recirculating-375
water system, under three load rates of rainbow376
trout Oncorhynchus mykiss. Revista Mexicana377
de Ingenierıa Quımica 6, 301-308.378
Autenrieth, R.L., Bonner, J.S., Akgerman, A.,379
Okaygum, M. and McCreary, E.M. (1991).380
Biodegradation of phenolic wastes. Journal of381
Hazardous Materials 28, 29-53.382
Bailey, J.E. and Ollis, D.F. (1986). Biochemical383
Engineering Fundamentals. 2da Edition,384
McGraw-Hill International Editions, Singapore.385
Beristain-Cardoso, R., Perez-Gonzalez, D.N.,386
Gonzalez-Blanco, G. and Gomez, J. (2011).387
Simultaneous oxidation of ammonium, p-388
cresol and sulfide using a nitrifying sludge in389
a multipurpose bioreactor: A novel alternative.390
Bioresource Technology 102, 3623-3625.391
Cervantes, F.J. (2009). Anthropogenic sources of N-392
pollutants and their impact on the environment393
and on public health. In: Environmental394
Technologies to Treat Nitrogen Pollution, (F.J.395
Cervantes, ed.), Pp. 1-17. IWA Publishing,396
London.397
Eiroa, M., Kennes, C. and Veiga, M.C. (2005).398
Simultaneous nitrification and formaldehyde399
biodegradation in an activated sludge unit.400
Bioresource Technology 96, 1914-1918.401
Haggblom, M.M., Rivera, M.D., Bossert, I.D.,402
Rogers, J.E. and Young, L.Y. (1990). Anaerobic403
biodegradation of para-cresol under three404
reducing conditions. Microbial Ecology 20,405
141-150.406
Hanaki, K., Wanatwin, C. and Ohgaki, S. (1990).407
Effects of the activity of heterotrophs on408
nitrification in a suspended-growth reactor.409
Water Research 24, 289-296.410
Lowry, O.H., Rosebrough, N.J., Farr, A.L. and411
Randall, R.J. (1951). Protein measurement with412
the folin phenol reagent. Journal of Biology and413
Chemistry 193, 265-275.414
Martınez-Hernandez, S., Texier, A-C., Cuervo-415
Lopez, F.M. and Gomez, J. (2011). 2-416
Chlorophenol consumption and its effect on417
the nitrifying sludge. Journal of Hazardous418
Materials 185, 1592-1595.419
Olmos, A., Olguin, P., Fajardo, C., Razo, E.420
and Monroy, O. (2004). Physicochemical421
characterization of spent caustic from the422
OXIMER process and sour waters from423
Mexican oil refineries. Energy & Fuels 18,424
302-304.425
Puig, S., Vives, M.T., Corominas, L.I., Balaguer,426
M.D. and Colprim, J. (2004). Wastewater427
nitrogen removal in SBRs, applying a step-feed428
strategy: from lab-scale to pilot-plant operation.429
Water Science and Technology 50, 89-96.430
Ramos-Nino, M.E., Ramirez-Rodriguez, A.,431
Clifford, M.N. and Adams, M.R. (1998).432
QSARs for the effect of benzaldehydes on433
foodborne bacteria and the role of sulfhydryl434
groups as targets of their antibacterial activity.435
Journal of Applied Microbiology 84, 207-212.436
Silva, C.D., Gomez, J., Houbron, E., Cuervo-437
Lopez, F.M. and Texier, A.C. (2009). p-cresol438
biotransformation by a nitrifying consortium.439
Chemosphere 75, 1387-1391.440
Silva, C.D., Gomez, J. and Beristain-Cardoso,441
R. (2011). Simultaneous removal of442
2-chlorophenol, phenol, p-cresol and443
p-hydroxybenzaldehyde under nitrifying444
conditions: Kinetic study. Bioresource445
Technology 102, 6464-6468.446
Singh, M. and Srivastava, R.K. (2011). Sequencing447
batch reactor technology for biological448
wastewater treatment: a review. Asia-Pacific449
Journal of Chemical Engineering 6, 3-13.450
Texier, A.-C. and Gomez, J. (2007). Simultaneous451
nitrification and p-cresol oxidation in a452
nitrifying sequencing batch reactor. Water453
Research 41, 315-322.454
van Schie, P.M. and Young, L.Y. (2000).455
Biodegradation of phenol: mechanisms and456
applications. Bioremediation Journal 4, 1-18.457
Vazquez, I., Rodrıguez, J., Maranon, E.,458
Castrillon, L. and Fernandez, Y. (2006).459
Simultaneous removal of phenol, ammonium460
and thiocyanate from coke wastewater by461
aerobic biodegradation. Journal of Hazardous462
Materials B173, 1773-1780.463
Yamagishi, T., Leite, J., Ueda, S., Yamaguchi, F.464
and Suwa, Y. (2001). Simultaneous removal465
www.rmiq.org 7
Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) XXX-XXX
nitrite removal rates in a closed recirculating-375
water system, under three load rates of rainbow376
trout Oncorhynchus mykiss. Revista Mexicana377
de Ingenierıa Quımica 6, 301-308.378
Autenrieth, R.L., Bonner, J.S., Akgerman, A.,379
Okaygum, M. and McCreary, E.M. (1991).380
Biodegradation of phenolic wastes. Journal of381
Hazardous Materials 28, 29-53.382
Bailey, J.E. and Ollis, D.F. (1986). Biochemical383
Engineering Fundamentals. 2da Edition,384
McGraw-Hill International Editions, Singapore.385
Beristain-Cardoso, R., Perez-Gonzalez, D.N.,386
Gonzalez-Blanco, G. and Gomez, J. (2011).387
Simultaneous oxidation of ammonium, p-388
cresol and sulfide using a nitrifying sludge in389
a multipurpose bioreactor: A novel alternative.390
Bioresource Technology 102, 3623-3625.391
Cervantes, F.J. (2009). Anthropogenic sources of N-392
pollutants and their impact on the environment393
and on public health. In: Environmental394
Technologies to Treat Nitrogen Pollution, (F.J.395
Cervantes, ed.), Pp. 1-17. IWA Publishing,396
London.397
Eiroa, M., Kennes, C. and Veiga, M.C. (2005).398
Simultaneous nitrification and formaldehyde399
biodegradation in an activated sludge unit.400
Bioresource Technology 96, 1914-1918.401
Haggblom, M.M., Rivera, M.D., Bossert, I.D.,402
Rogers, J.E. and Young, L.Y. (1990). Anaerobic403
biodegradation of para-cresol under three404
reducing conditions. Microbial Ecology 20,405
141-150.406
Hanaki, K., Wanatwin, C. and Ohgaki, S. (1990).407
Effects of the activity of heterotrophs on408
nitrification in a suspended-growth reactor.409
Water Research 24, 289-296.410
Lowry, O.H., Rosebrough, N.J., Farr, A.L. and411
Randall, R.J. (1951). Protein measurement with412
the folin phenol reagent. Journal of Biology and413
Chemistry 193, 265-275.414
Martınez-Hernandez, S., Texier, A-C., Cuervo-415
Lopez, F.M. and Gomez, J. (2011). 2-416
Chlorophenol consumption and its effect on417
the nitrifying sludge. Journal of Hazardous418
Materials 185, 1592-1595.419
Olmos, A., Olguin, P., Fajardo, C., Razo, E.420
and Monroy, O. (2004). Physicochemical421
characterization of spent caustic from the422
OXIMER process and sour waters from423
Mexican oil refineries. Energy & Fuels 18,424
302-304.425
Puig, S., Vives, M.T., Corominas, L.I., Balaguer,426
M.D. and Colprim, J. (2004). Wastewater427
nitrogen removal in SBRs, applying a step-feed428
strategy: from lab-scale to pilot-plant operation.429
Water Science and Technology 50, 89-96.430
Ramos-Nino, M.E., Ramirez-Rodriguez, A.,431
Clifford, M.N. and Adams, M.R. (1998).432
QSARs for the effect of benzaldehydes on433
foodborne bacteria and the role of sulfhydryl434
groups as targets of their antibacterial activity.435
Journal of Applied Microbiology 84, 207-212.436
Silva, C.D., Gomez, J., Houbron, E., Cuervo-437
Lopez, F.M. and Texier, A.C. (2009). p-cresol438
biotransformation by a nitrifying consortium.439
Chemosphere 75, 1387-1391.440
Silva, C.D., Gomez, J. and Beristain-Cardoso,441
R. (2011). Simultaneous removal of442
2-chlorophenol, phenol, p-cresol and443
p-hydroxybenzaldehyde under nitrifying444
conditions: Kinetic study. Bioresource445
Technology 102, 6464-6468.446
Singh, M. and Srivastava, R.K. (2011). Sequencing447
batch reactor technology for biological448
wastewater treatment: a review. Asia-Pacific449
Journal of Chemical Engineering 6, 3-13.450
Texier, A.-C. and Gomez, J. (2007). Simultaneous451
nitrification and p-cresol oxidation in a452
nitrifying sequencing batch reactor. Water453
Research 41, 315-322.454
van Schie, P.M. and Young, L.Y. (2000).455
Biodegradation of phenol: mechanisms and456
applications. Bioremediation Journal 4, 1-18.457
Vazquez, I., Rodrıguez, J., Maranon, E.,458
Castrillon, L. and Fernandez, Y. (2006).459
Simultaneous removal of phenol, ammonium460
and thiocyanate from coke wastewater by461
aerobic biodegradation. Journal of Hazardous462
Materials B173, 1773-1780.463
Yamagishi, T., Leite, J., Ueda, S., Yamaguchi, F.464
and Suwa, Y. (2001). Simultaneous removal465
www.rmiq.org 7www.rmiq.org 103
![Page 8: Revista Mexicana de Vol. 12, No. 1 (2013) 97-104 ... · Revista Mexicana de Ingeniería Q uímica CONTENIDO Volumen 8, número 3, 2009 / Volume 8, number 3, ... Esta informacion puede](https://reader034.fdocuments.net/reader034/viewer/2022042217/5ebfee19685674328e627319/html5/thumbnails/8.jpg)
Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) 97-104Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) XXX-XXX
of phenol and ammonia by an activated sludge466
process with cross-flow filtration. Water467
Research 35, 3089-3096.468
Zhuang, W.-Q., Tay, J.-H., Yi, S. and Tay, T.-L.S.469
(2005). Microbial adaptation to biodegradation470
of tert-butyl alcohol in a sequencing batch471
reactor. Journal of Biotechnology 118, 45-53.472
8 www.rmiq.org
Tellez-Perez et al./ Revista Mexicana de Ingenierıa Quımica Vol. 12, No. 1 (2013) XXX-XXX
of phenol and ammonia by an activated sludge466
process with cross-flow filtration. Water467
Research 35, 3089-3096.468
Zhuang, W.-Q., Tay, J.-H., Yi, S. and Tay, T.-L.S.469
(2005). Microbial adaptation to biodegradation470
of tert-butyl alcohol in a sequencing batch471
reactor. Journal of Biotechnology 118, 45-53.472
8 www.rmiq.org104 www.rmiq.org