Chapter 7
Treatability Study of Municipal
Wastewater in Fixed-Bed Hybrid
Bioreactor
7.1 Criteria for Selection of Wastewater
In the medium and small town, the strength of wastewater varies mostly due to disintegrated sewerage systems. In case of low to medium strength municipal wastewater,
main problem for treatment is sustaining the biomass in the reactor without the
return sludge, i.e., settled biomass from the secondary clarifier. Presently, adequate
biomass is maintained through extended aeration and with sludge recirculation,
which increases the overall cost of treatment on account of pumping. In case of
especially low strength municipal wastewater, which is highly biodegradable, the
suspended biomass in the reactor tends to get washed out rapidly if there is no
recirculation of settled biomass. Thus, the introduction of attached biomass into
the suspended-growth system can be reasonably thought for maintaining sufficient
biomass in the reactor. The footprint area of such integrated system, i.e., hybrid bioreactor is thus small compared to the conventional ASP, thereby making the economy
of the treatment system.
7.2 Modality of Treatment of Municipal Wastewater
in the Laboratory-Scale Reactor
For performance evaluation of the reactor as well as for validation of the proposed
mathematical model, initiative was taken up for conducting both the batch and continuous mode operation of the fixed-bed hybrid bioreactor. The laboratory-scale hybrid
bioreactor was run under semi-batch mode using municipal wastewater for determining the kinetic coefficients based on the graphical method as developed from
the mathematical modeling. Continuous study was performed with the municipal
wastewater under various hydraulic retention time (HRT) and biomass concentration.
The validation of the mathematical modeling with the real municipal wastewater was
done considering the kinetic coefficients derived from the semi-batch study.
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
S. Sarkar, Fixed Bed Hybrid Bioreactor, Green Energy and Technology,
https://doi.org/10.1007/978-981-33-4546-1_7
95
Treatability Study of Municipal
Wastewater in Fixed-Bed Hybrid
Bioreactor
7.1 Criteria for Selection of Wastewater
In the medium and small town, the strength of wastewater varies mostly due to disintegrated sewerage systems. In case of low to medium strength municipal wastewater,
main problem for treatment is sustaining the biomass in the reactor without the
return sludge, i.e., settled biomass from the secondary clarifier. Presently, adequate
biomass is maintained through extended aeration and with sludge recirculation,
which increases the overall cost of treatment on account of pumping. In case of
especially low strength municipal wastewater, which is highly biodegradable, the
suspended biomass in the reactor tends to get washed out rapidly if there is no
recirculation of settled biomass. Thus, the introduction of attached biomass into
the suspended-growth system can be reasonably thought for maintaining sufficient
biomass in the reactor. The footprint area of such integrated system, i.e., hybrid bioreactor is thus small compared to the conventional ASP, thereby making the economy
of the treatment system.
7.2 Modality of Treatment of Municipal Wastewater
in the Laboratory-Scale Reactor
For performance evaluation of the reactor as well as for validation of the proposed
mathematical model, initiative was taken up for conducting both the batch and continuous mode operation of the fixed-bed hybrid bioreactor. The laboratory-scale hybrid
bioreactor was run under semi-batch mode using municipal wastewater for determining the kinetic coefficients based on the graphical method as developed from
the mathematical modeling. Continuous study was performed with the municipal
wastewater under various hydraulic retention time (HRT) and biomass concentration.
The validation of the mathematical modeling with the real municipal wastewater was
done considering the kinetic coefficients derived from the semi-batch study.
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
S. Sarkar, Fixed Bed Hybrid Bioreactor, Green Energy and Technology,
https://doi.org/10.1007/978-981-33-4546-1_7
95