INHIBITION KINETICS DURING THE OXIDATION OF BINARY MIXTURES OF PHENOL WITH CATECHOL, RESORCINOL AND HYDROQUINONE BY PHENOL ACCLIMATED ACTIVATED SLUDGE

Lobo, C. C.; Bertola, N. C.; Contreras, E. M.

doi:10.1590/0104-6632.20160331s20150173

C. C. Lobo

Centro de Investigación y Desarrollo en Criotecnología de Alimentos, (CIDCA), CONICET, Fac. de Cs. Exactas, UNLP. 47 y 116 (B1900AJJ), La Plata, Argentina. Phone: + 54 221 4254853. E-mail: cintiacecilialobo@hotmail.com

* To whom correspondence should be addressed

N. C. Bertola

Centro de Investigación y Desarrollo en Criotecnología de Alimentos, (CIDCA), CONICET, Fac. de Cs. Exactas, UNLP. 47 y 116 (B1900AJJ), La Plata, Argentina. Phone: + 54 221 4254853. E-mail: cintiacecilialobo@hotmail.com

E. M. Contreras

Instituto de Investigaciones en Ciencia y Tecnología de Materiales (INTEMA), CONICET-Mar del Plata, Av. Juan B. Justo 4302, (7600) Mar del Plata, Argentina.

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Figure 1
Typical examples of DO profiles (a,c) and the corresponding OUR_ex (b,d) during the biodegradation of phenol (a,b) and catechol (c,d) by phenol-acclimated activated sludge. Lines indicate the proposed model ( to ). Experimental conditions: (a,b) X = 3.1 gTSS L^-1, k_La = 19 h^-1, S₀ = 1.06 mM; (c,d) X = 1.3 gTSS L^-1, k_La = 23 h^-1, S₀ = 0.91 mM.

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Figure 2
Typical examples of DO profiles (a,c) and the corresponding OUR_ex (b,d) during the biodegradation of resorcinol (a,b) and hydroquinone (c,d) by phenol-acclimated activated sludge. Lines indicate the fitted kinetic model ( to ). Experimental conditions: (a,b) X = 2.1 gTSS L^-1, k_La = 14 h^-1, S₀ = 0.91 mM; (c,d) X = 2.7 gTSS L^-1, k_La = 10 h^-1, S₀ = 0.91 mM.

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Figure 3
DO profile (a) and the corresponding OUR_ex (b) during the biodegradation of phenol (PH, 1.06 mM), catechol (CA, 0.45 mM), and the mixture of phenol (1.06 mM) and catechol (0.45 mM) (PH+CA) by phenol-acclimated activated sludge. Dotted lines indicate each cycle of addition of substrates.

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Figure 4
DO profile (a) and the corresponding OUR_ex (b) during the biodegradation of phenol (PH, 1.06 mM), resorcinol (RE, 0.45 mM), and the mixture of phenol (1.06 mM) and resorcinol (0.45 mM) (PH+RE) by phenol-acclimated activated sludge. Dotted lines indicate each cycle of addition of substrates.

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Figure 5
DO profile (a) and the corresponding OUR_ex (b) during the biodegradation of phenol (PH, 1.06 mM), hydroquinone (HY, 0.45 mM), and the mixture of phenol (1.06 mM) and hydroquinone (0.45 mM) (PH+HY) by phenol-acclimated activated sludge. Dotted lines indicate each cycle of addition of substrates.

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Figure 6
Examples of oxygen uptake rate (OUR_ex, circles) and oxygen consumed (OC, dashed lines) during the oxidation of: a) PH+CA (black) and CA alone (grey), b) PH+RE (black) and PH alone (grey), c) PH+HY (black) and PH alone (grey). Dotted lines indicate the time corresponding to the end of the first phase of the respirogram. OC₁ = OC of the first phase, OC_T = total OC. Continuous lines represent the proposed model ( to )

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Figure 7
Cumulative oxygen consumption (Sum(OC)) as a function of the cumulative substrate concentration (Sum(S)) corresponding to the mixtures a) PH+CA, b) PH+RE and c) PH+HY. Grey planes in a, c and e represent using the oxidation coefficients depicted in . Continuous lines in b, d and e represent the identity line; dashed lines represent ±15% of the experimental value.

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Figure 8
Effect of the inhibition constant (K_inA/B) on the oxidation of the substrate A (PH, a; RE, b; HY, c) due to the presence of B (CA, a; PH, b, c). Continuous lines represent the percentage of A consumed during the first part of the simulated respirogram (A₁) using the proposed model ( to ) with the coefficients depicted in ; dashed lines indicate experimental A₁ values (). Dotted lines indicate K_inA/B values for which the experimental and simulated A₁ values were similar.

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Table 1
Kinetic coefficients corresponding to the aerobic degradation of phenol (PH), catechol (CA), resorcinol (RE) and hydroquinone (HY) by phenol-acclimated activated sludge (mean ± confidence interval at a 95% confidence level are reported)

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Table 2
Oxygen consumption during the first phase of the respirogram (OC₁), total oxygen consumption (OC_T) and fraction of PH and RE (or HY) consumed during the first phase of the respirograms shown in Figures 3 to 5 corresponding to the binary mixtures studied.

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C instantaneous dissolved oxygen (DO) concentration (mM) CA0 initial catechol concentrations (mM) Ce DO concentration in the absence of an oxidizable substrate (mM) DO Dissolved oxygen (mM) Ki substrate inhibition coefficient (mM) KinA/B inhibition constant for the consumption of A due to the presence of B (mM) KinPH/CA inhibition constant for phenol in the presence of catechol (mM h-1) KinZ/PH inhibition constant for Z (RE or HY) in the presence of phenol (mM h-1) kLa oxygen mass transfer coefficient (h-1) KO2 oxygen saturation coefficient (mM) KS substrate saturation coefficient (mM) OC1 oxygen consumption during the first phase of the respirogram (mM) OCT total oxygen consumed (mM) OURex oxygen uptake rate associated with the substrate oxidation (mM h-1) PH0 Initial phenol concentrations (mM) qO2m maximum specific oxygen consumption rate (mmol gTSS-1 h-1) qSm maximum specific substrate consumption rate (mmol gTSS-1 h-1) RCA consumption rate corresponding to catechol (mM h-1) RPH consumption rate corresponding to phenol (mM h-1) RS substrate consumption rate (mM h-1) RZ consumption rate corresponding to Z, where Z is resorcinol or hydroquinone (mM h-1) S substrate concentration (mM) Sum(OC) cumulative oxygen consumption (mM) Sum(S) cumulative substrate concentration (mM) t time (h) YO/CA oxidation coefficient for catechol (mol/mol) YO/PH oxidation coefficient for phenol (mol/mol) YO/S oxidation coefficient for S, where S represents CA, RE or HY (mol/mol) Z0 initial concentration of RE or HY (mM)

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	q_Sm(mmol gTSS^-1 h^-1)	K_S (mM)	K_i (mM)	KO₂ (mM)	Y_O/S (mol/mol)
PH	1.82 ± 0.26	0.021 ± 0.004	2.1 ± 0.6	0.06^* * from Contreras et al. (2008)	1.52 ± 0.07
CA	7.40 ± 1.21	0.045 ± 0.030	^n.a. n.a. : not applicable	0.087 ± 0.018	0.87 ± 0.13
RE	0.26 ± 0.11	0.013 ± 0.004	3.6 ± 1.4	^n.a. n.a. : not applicable	2.04 ± 0.11
HY	0.20 ± 0.04	0.029 ± 0.010	1.7 ± 0.5	^n.a. n.a. : not applicable	2.05 ± 0.41

	PH+CA			PH+RE			PH+HY
Test number	OC₁ (mM)	OC_T (mM)	*f_PH1(%)^ * Eq. (12) using YO/PH = 1.52, YO/CA = 0.87, PH0 = 1.06 mM, CA0 = 0.45 mM**	OC₁ (mM)	OC_T (mM)	f_RE1(%)^ Eq. (13) using YO/PH = 1.52, YO/RE = 2.04, YO/HY = 2.05, PH0 = 1.06 mM, RE0 = 0.45 mM, HY0 = 0.45 mM	OC₁ (mM)	OC_T (mM)	f_HY1(%)^ Eq. (13) using YO/PH = 1.52, YO/RE = 2.04, YO/HY = 2.05, PH0 = 1.06 mM, RE0 = 0.45 mM, HY0 = 0.45 mM
1	0.49	2.15	4.0	2.33	3.16	27.6	2.16	3.08	17.9
2	0.39	1.61	5.8	2.00	2.63	34.0	2.00	2.84	18.7
3	0.31	1.49	1.6	1.64	2.29	21.8	1.99	2.69	28.5
4	0.44	1.75	6.9	1.94	2.67	24.7	1.93	2.73	19.5
5	0.56	2.04	9.8	1.62	2.21	26.4
6	0.37	1.64	3.7
Mean	0.42	1.78	5.3	1.91	2.59	26.9	2.02	2.84	21.2
Confidence interval (95%)	0.10	0.27	3.0	0.36	0.47	5.6	0.16	0.28	7.8

C	instantaneous dissolved oxygen (DO) concentration (mM)
CA₀	initial catechol concentrations (mM)
C_e	DO concentration in the absence of an oxidizable substrate (mM)
DO	Dissolved oxygen (mM)
Ki	substrate inhibition coefficient (mM)
K_inA/B	inhibition constant for the consumption of A due to the presence of B (mM)
K_inPH/CA	inhibition constant for phenol in the presence of catechol (mM h^-1)
K_inZ/PH	inhibition constant for Z (RE or HY) in the presence of phenol (mM h^-1)
k_La	oxygen mass transfer coefficient (h^-1)
K_O2	oxygen saturation coefficient (mM)
K_S	substrate saturation coefficient (mM)
OC₁	oxygen consumption during the first phase of the respirogram (mM)
OC_T	total oxygen consumed (mM)
OUR_ex	oxygen uptake rate associated with the substrate oxidation (mM h^-1)
PH₀	Initial phenol concentrations (mM)
qO_2m	maximum specific oxygen consumption rate (mmol gTSS^-1 h^-1)
q_Sm	maximum specific substrate consumption rate (mmol gTSS^-1 h^-1)
R_CA	consumption rate corresponding to catechol (mM h^-1)
R_PH	consumption rate corresponding to phenol (mM h^-1)
R_S	substrate consumption rate (mM h^-1)
R_Z	consumption rate corresponding to Z, where Z is resorcinol or hydroquinone (mM h^-1)
S	substrate concentration (mM)
Sum(OC)	cumulative oxygen consumption (mM)
Sum(S)	cumulative substrate concentration (mM)
t	time (h)
Y_O/CA	oxidation coefficient for catechol (mol/mol)
Y_O/PH	oxidation coefficient for phenol (mol/mol)
Y_O/S	oxidation coefficient for S, where S represents CA, RE or HY (mol/mol)
Z₀	initial concentration of RE or HY (mM)

[TFN01] ^n.a.
: not applicable

[TFN02] ^*
from Contreras et al. (2008)

Brasil

Brasil

INHIBITION KINETICS DURING THE OXIDATION OF BINARY MIXTURES OF PHENOL WITH CATECHOL, RESORCINOL AND HYDROQUINONE BY PHENOL ACCLIMATED ACTIVATED SLUDGE

Abstract