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5 Fabrication of Fixed-Bed Hybrid Bioreactor and Hydraulic Studies
5.2 Hydraulic Study on Fixed-Bed Hybrid Bioreactor
Tracer response study was performed to assess the hydraulic performance of the
full-scale reactor used for the treatment of municipal wastewater. The objective of
the study was to establish the hydraulic regime of the laboratory-scale fixed-bed
hybrid bioreactor. The use of inert tracers for developing the residence time distribution curves is one of the simplest and well-established method for ascertaining the
hydraulic regime of the full-scale reactor under any given operating condition.
5.2.1 Approach
The tracer study was conducted under slug input of the tracer at the inlet point and
concurrent measurement of tracer concentration at the outlet point. For this purpose,
lithium chloride (LiCl) as a tracer was used which is very much compatible with the
biological environment. After initiation, at an interval of 15 and 30 min the effluent
was collected from the secondary clarifier and the tracer concentration for the same
was measured for a series of grab samples. The tracer study was conducted for the
MLSS concentration in the range of 2000–2500 mg/l and HRT between 4 and 8 h.
Tracer study in each run was continued until two successive tracer concentrations
remain more or less same. In order to set any HRT say 4 h, the flow rate was adjusted
by means of a peristaltic pump. The amount of tracer concentration was varied from
100 to 500 mg/l. Finally, tracer response curves were drawn in respect of C/C 0 versus
t/t o profile, where, C 0 and C are initial and final tracer concentration corresponding
to t 0 and t, respectively, where t is the actual detention time and t 0 is the theoretical
detention time.
5.2.2 Theoretical Aspect of Tracer Response Curves
For an ideal flow in completely mixed reactor, the ideal tracer response profile can
be represented by [1]
C = C 0 e
−(t/t 0 )
= C 0 e
−θ
Or,
C/C 0 = e
−θ
(5.1)
C 0 = Initial concentration of the tracer in the reactor (mg/l).
C = Concentration of the tracer in the reactor at time t (mg/l).
5 Fabrication of Fixed-Bed Hybrid Bioreactor and Hydraulic Studies
5.2 Hydraulic Study on Fixed-Bed Hybrid Bioreactor
Tracer response study was performed to assess the hydraulic performance of the
full-scale reactor used for the treatment of municipal wastewater. The objective of
the study was to establish the hydraulic regime of the laboratory-scale fixed-bed
hybrid bioreactor. The use of inert tracers for developing the residence time distribution curves is one of the simplest and well-established method for ascertaining the
hydraulic regime of the full-scale reactor under any given operating condition.
5.2.1 Approach
The tracer study was conducted under slug input of the tracer at the inlet point and
concurrent measurement of tracer concentration at the outlet point. For this purpose,
lithium chloride (LiCl) as a tracer was used which is very much compatible with the
biological environment. After initiation, at an interval of 15 and 30 min the effluent
was collected from the secondary clarifier and the tracer concentration for the same
was measured for a series of grab samples. The tracer study was conducted for the
MLSS concentration in the range of 2000–2500 mg/l and HRT between 4 and 8 h.
Tracer study in each run was continued until two successive tracer concentrations
remain more or less same. In order to set any HRT say 4 h, the flow rate was adjusted
by means of a peristaltic pump. The amount of tracer concentration was varied from
100 to 500 mg/l. Finally, tracer response curves were drawn in respect of C/C 0 versus
t/t o profile, where, C 0 and C are initial and final tracer concentration corresponding
to t 0 and t, respectively, where t is the actual detention time and t 0 is the theoretical
detention time.
5.2.2 Theoretical Aspect of Tracer Response Curves
For an ideal flow in completely mixed reactor, the ideal tracer response profile can
be represented by [1]
C = C 0 e
−(t/t 0 )
= C 0 e
−θ
Or,
C/C 0 = e
−θ
(5.1)
C 0 = Initial concentration of the tracer in the reactor (mg/l).
C = Concentration of the tracer in the reactor at time t (mg/l).