8.2 Methodology for Experimental Validation
113
Accordingly, a best-fit line was drawn for this scatter diagram as shown in Fig. 8.4
of Annexure VI-a with a relationship y = −0.021x + 0.129. Considering p = 0.93, the
value of k was determined from the intercept value. In addition, the yield coefficient,
i.e., Y was obtained from the relationship Y = μ max /k.
Now, from Fig. 8.4 of Annexure VI-a, 1/pk = 0.129 day, p = porosity = 0.93.
Hence, k = 8.33 day
−1 , Y = μ max /k = 6.36/8.33 = 0.76.
The value of Y showed a higher value in comparison with that for municipal
wastewater, as stated in earlier literatures, presumably exhibiting high rate of organic
conversion.
8.2.2.3 Determination of B s , B t and B d
In order to determine b s , b t and b d , the biomass balance for hybrid bioreactor system
at steady-state condition was considered. It was represented by the equation YAJ/PX
= 1/θ c − (YkS w )/(K s + S w )) (Ref. Clause 3.2, Chapter 3), where J=substrate flux
within the attached-growth system, θ c = solid retention time (SRT).
Now, θ c is calculated as p* θ for the case of no recirculation. The values of (1/θ c
− (YkS w )/(K s + S w )) and (YaJ)/(pX) are presented in Table 8.2.
Accordingly, a best-fit line was drawn as shown in Fig. 8.6. The slope of the
best-fit equation, i.e., y = 2.284x + 0.354, represents the values of (b s + b d )/b s .
On the other hand, the intersection of Y-axis represents the value b d (b s + b d )/b s .
The coefficient of total biomass loss, i.e., b t , can be calculated as b t =b s + b d . From
Fig. 8.6, m = 2.284 and c = 0.354, which shows biomass decay loss is 0.15 day
−1 ,
biomass shear loss is 0.12 day
-1 and total biomass loss is 0.27 day
−1 (Ref. Sect. 3.2,
Chapter 3).
Therefore, the kinetic coefficients and physical data used for the prediction of
the effluent substrate (COD) concentration under continuous study with municipal
wastewater are as follows:
k = 8.33 day
−1 , Y = 0.76, K = 0.012 mg/cm
3 , b t = 0.27 day
−1 , b s = 0.12 day
−1 ,
b d = 0.15 day
−1 , D f = 0.64 cm
2 /day (assumed).
8.3 Plotting of Predicted and Observed COD Concentration
The output data like effluent substrate concentration (i.e., COD) were experimentally obtained in continuous study with both synthetic carbonaceous and municipal wastewater. The experimental COD concentration was then compared with that
derived from computer programming for establishing the accuracy of the present
model. To accomplish this, the observed COD concentrations were plotted in Yaxis with respect to the COD concentrations predicted from the model in X-axis.
A 45° line as well as two lines representing (+/−) 10% deviation was also drawn
to understand the closeness of the experimental and predicted data. The graphical
presentation of this comparison is shown in Figs. 8.7 and 8.8.
113
Accordingly, a best-fit line was drawn for this scatter diagram as shown in Fig. 8.4
of Annexure VI-a with a relationship y = −0.021x + 0.129. Considering p = 0.93, the
value of k was determined from the intercept value. In addition, the yield coefficient,
i.e., Y was obtained from the relationship Y = μ max /k.
Now, from Fig. 8.4 of Annexure VI-a, 1/pk = 0.129 day, p = porosity = 0.93.
Hence, k = 8.33 day
−1 , Y = μ max /k = 6.36/8.33 = 0.76.
The value of Y showed a higher value in comparison with that for municipal
wastewater, as stated in earlier literatures, presumably exhibiting high rate of organic
conversion.
8.2.2.3 Determination of B s , B t and B d
In order to determine b s , b t and b d , the biomass balance for hybrid bioreactor system
at steady-state condition was considered. It was represented by the equation YAJ/PX
= 1/θ c − (YkS w )/(K s + S w )) (Ref. Clause 3.2, Chapter 3), where J=substrate flux
within the attached-growth system, θ c = solid retention time (SRT).
Now, θ c is calculated as p* θ for the case of no recirculation. The values of (1/θ c
− (YkS w )/(K s + S w )) and (YaJ)/(pX) are presented in Table 8.2.
Accordingly, a best-fit line was drawn as shown in Fig. 8.6. The slope of the
best-fit equation, i.e., y = 2.284x + 0.354, represents the values of (b s + b d )/b s .
On the other hand, the intersection of Y-axis represents the value b d (b s + b d )/b s .
The coefficient of total biomass loss, i.e., b t , can be calculated as b t =b s + b d . From
Fig. 8.6, m = 2.284 and c = 0.354, which shows biomass decay loss is 0.15 day
−1 ,
biomass shear loss is 0.12 day
-1 and total biomass loss is 0.27 day
−1 (Ref. Sect. 3.2,
Chapter 3).
Therefore, the kinetic coefficients and physical data used for the prediction of
the effluent substrate (COD) concentration under continuous study with municipal
wastewater are as follows:
k = 8.33 day
−1 , Y = 0.76, K = 0.012 mg/cm
3 , b t = 0.27 day
−1 , b s = 0.12 day
−1 ,
b d = 0.15 day
−1 , D f = 0.64 cm
2 /day (assumed).
8.3 Plotting of Predicted and Observed COD Concentration
The output data like effluent substrate concentration (i.e., COD) were experimentally obtained in continuous study with both synthetic carbonaceous and municipal wastewater. The experimental COD concentration was then compared with that
derived from computer programming for establishing the accuracy of the present
model. To accomplish this, the observed COD concentrations were plotted in Yaxis with respect to the COD concentrations predicted from the model in X-axis.
A 45° line as well as two lines representing (+/−) 10% deviation was also drawn
to understand the closeness of the experimental and predicted data. The graphical
presentation of this comparison is shown in Figs. 8.7 and 8.8.