Chapter 1
Introduction
1.1 Background
Due to the rapid increase in population growth, urbanization, industrialization and
more luxurious lifestyles, huge amount of pollutants are produced day by day and
discarded into the water system. Billions of gallons of wastewater are produced
every day from domestic and industrial sources. Due to the adverse effect of
different pollutants of wastewater on the surrounding water environment, wastewater treatment becomes inevitable nowadays. The treatment of wastewater should
be adequate enough to satisfy the discharge standard so that potential of the final
effluent remains within natural purification capacity of the watercourse. Biological
treatment method plays an important role in removing biodegradable carbonaceous
matter from domestic and industrial wastewater. Out of various biological methods
activated sludge process (ASP) and its several modifications are widely being used
throughout the world. Apart from that, attached-growth fixed-film system can also
be used for the biological treatment of both domestic and industrial wastewater.
Among these two, activated sludge process exhibited better flexibility in operation
to improve the effluent quality. The ASP system can also be used for simultaneous
carbon oxidation and nitrification in its modified configurations.
However, activated sludge process has also experienced some inherent problems
while functioning in the wastewater treatment plants. The major problems encountered by this process are to maintain the uniform biomass concentration in the aeration tank, increased volume of tank, incapability of the biomass to resist the shock
effect due to sudden increase in the organic load in wastewater, poor settleability in
secondary clarifier, inadequacy to withstand toxic and inhibitory substances, high
power inputs toward pumping for recirculation, etc. Even, for the treatment of
low strength wastewater like municipal wastewater, biomass in the activated sludge
process is susceptible to washout if there is no recirculation of biomass To alleviate
these limitations and operational problems of ASP, the current practice is to integrate
the fixed-film media into activated sludge reactor, which is emerged as integrated
fixed-film activated sludge system, also known as aerobic hybrid bioreactor.
© 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_1
1
Introduction
1.1 Background
Due to the rapid increase in population growth, urbanization, industrialization and
more luxurious lifestyles, huge amount of pollutants are produced day by day and
discarded into the water system. Billions of gallons of wastewater are produced
every day from domestic and industrial sources. Due to the adverse effect of
different pollutants of wastewater on the surrounding water environment, wastewater treatment becomes inevitable nowadays. The treatment of wastewater should
be adequate enough to satisfy the discharge standard so that potential of the final
effluent remains within natural purification capacity of the watercourse. Biological
treatment method plays an important role in removing biodegradable carbonaceous
matter from domestic and industrial wastewater. Out of various biological methods
activated sludge process (ASP) and its several modifications are widely being used
throughout the world. Apart from that, attached-growth fixed-film system can also
be used for the biological treatment of both domestic and industrial wastewater.
Among these two, activated sludge process exhibited better flexibility in operation
to improve the effluent quality. The ASP system can also be used for simultaneous
carbon oxidation and nitrification in its modified configurations.
However, activated sludge process has also experienced some inherent problems
while functioning in the wastewater treatment plants. The major problems encountered by this process are to maintain the uniform biomass concentration in the aeration tank, increased volume of tank, incapability of the biomass to resist the shock
effect due to sudden increase in the organic load in wastewater, poor settleability in
secondary clarifier, inadequacy to withstand toxic and inhibitory substances, high
power inputs toward pumping for recirculation, etc. Even, for the treatment of
low strength wastewater like municipal wastewater, biomass in the activated sludge
process is susceptible to washout if there is no recirculation of biomass To alleviate
these limitations and operational problems of ASP, the current practice is to integrate
the fixed-film media into activated sludge reactor, which is emerged as integrated
fixed-film activated sludge system, also known as aerobic hybrid bioreactor.
© 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_1
1