treatment is necessary. Conventional methods of treatment are cumbersome requiring large footprints, use of chemicals, and subsequent management of sludge
generated.
Membrane is a barrier which helps in the preferential transport of some species
under a potential gradient, be it mechanical, chemical, or electrical. Membranes can
be made from different materials, in different forms, and with different morphologies. Membranes can be porous or nonporous, charged or neutral, and solid or
liquid. Because of its flexibility, a variety of membrane processes has been developed and is being used to mitigate many industrial challenges. Membrane processes
used in wastewater treatment are ambient temperature processes with no phase
change and are rate-governed. The chemical requirements are significantly less
compared to conventional processes leading to less sludge production.
An overview of different membrane processes motivated by pressure, concentration, and thermal and electrical gradients is discussed in the context of mitigating
water stress situations. The technologies discussed include desalination, water
recovery, and recycle and removal of toxic contaminants from wastewater streams
including the latest developments in application areas. Utility of membrane
contactors in improving the performance of the conventional separation processes
is highlighted through membrane solvent extraction, supported liquid membranes,
and membrane bioreactors. The potential applications of forward osmosis in water
treatment are also indicated.
The roles of electrically driven membrane processes such as electrodialysis, bipolar
membrane-based electrodialysis, electrodialysis reversal, and electro-deionization in
water treatment are explained along with its limitations and challenges. The role of
membranes in providing safe drinking water at the point of use has also been
highlighted.
The prospects of combining two or more membrane processes like nanofiltration,
reverse osmosis, and electrodialysis in water and wastewater treatment are
highlighted. With increasing environmental consciousness and the need to recover
value from waste, the concept of decentralization of wastewater treatment is proposed wherein the source of waste is isolated, as membrane processes can operate on
any scale.
In the future, environmental protection is going to become a critical concern, and
the best strategy is to recover everything in the wastewater stream as value toward
realizing the concept of “Waste is unutilized Wealth.” The best way to achieve this is
by isolating the individual wastewater streams as produced and treating them at the
source without mixing with other waste streams. In this context, membrane processes have varieties and are economically viable for different capacities. Since the
various streams are isolated, both the product and retentate streams can be recycled,
thus leading not only to recovering value but also zero discharge to the environment.
This chapter aims at providing necessary background knowledge to select a suitable
scheme for the treatment of the specific wastewater including point-of-use devices
and value recovery.
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A. Kapoor et al.
generated.
Membrane is a barrier which helps in the preferential transport of some species
under a potential gradient, be it mechanical, chemical, or electrical. Membranes can
be made from different materials, in different forms, and with different morphologies. Membranes can be porous or nonporous, charged or neutral, and solid or
liquid. Because of its flexibility, a variety of membrane processes has been developed and is being used to mitigate many industrial challenges. Membrane processes
used in wastewater treatment are ambient temperature processes with no phase
change and are rate-governed. The chemical requirements are significantly less
compared to conventional processes leading to less sludge production.
An overview of different membrane processes motivated by pressure, concentration, and thermal and electrical gradients is discussed in the context of mitigating
water stress situations. The technologies discussed include desalination, water
recovery, and recycle and removal of toxic contaminants from wastewater streams
including the latest developments in application areas. Utility of membrane
contactors in improving the performance of the conventional separation processes
is highlighted through membrane solvent extraction, supported liquid membranes,
and membrane bioreactors. The potential applications of forward osmosis in water
treatment are also indicated.
The roles of electrically driven membrane processes such as electrodialysis, bipolar
membrane-based electrodialysis, electrodialysis reversal, and electro-deionization in
water treatment are explained along with its limitations and challenges. The role of
membranes in providing safe drinking water at the point of use has also been
highlighted.
The prospects of combining two or more membrane processes like nanofiltration,
reverse osmosis, and electrodialysis in water and wastewater treatment are
highlighted. With increasing environmental consciousness and the need to recover
value from waste, the concept of decentralization of wastewater treatment is proposed wherein the source of waste is isolated, as membrane processes can operate on
any scale.
In the future, environmental protection is going to become a critical concern, and
the best strategy is to recover everything in the wastewater stream as value toward
realizing the concept of “Waste is unutilized Wealth.” The best way to achieve this is
by isolating the individual wastewater streams as produced and treating them at the
source without mixing with other waste streams. In this context, membrane processes have varieties and are economically viable for different capacities. Since the
various streams are isolated, both the product and retentate streams can be recycled,
thus leading not only to recovering value but also zero discharge to the environment.
This chapter aims at providing necessary background knowledge to select a suitable
scheme for the treatment of the specific wastewater including point-of-use devices
and value recovery.
248
A. Kapoor et al.