17 Scope of Conventional Versus Advanced Technologies …
399
difficult and tricky task. The conventional methods of treating wastewater are based
upon preliminary, primary, secondary, and tertiary treatment technologies which
involve the biological, physical, and chemical processes. The most frequently used
biological process of treating wastewater is by means of activated sludge. Although
the usual method of biological treatment is greatly efficient as it uses lesser space in
comparison with the non-conventional methods of treatment and its performance is
also independent of outdoor conditions, there are some drawbacks of these treatments
as well. These include constant high electrical energy requirements, the design and
maintenance, supervision, and overall the general cost of production that requires
extremely skilled workers. Similarly, the membranes which are used for the removal
of organic precursor matter are highly effective for the treatment of other emerging contaminants as well but here too; size exclusion is very significant and determines membrane capability. Both MF and UF are useful in removing pathogens from
wastewater but they are limited only to the removal of bacteria and allow viruses and
mycoplasms to pass through them. The membranes are highly sensitive to oxidative chemicals like nitric and sulfuric acids and also to peroxides and persulphates.
The processes of RO and NF have the broadest range of treatment ability and have
proved to be a good substitute of conventional treatment technologies. However,
both are diffusion and size exclusion controlled processes and require high degree
of pretreatment. NF removes harmful contaminates like pesticides and other organic
macromolecules but retains minerals that have to be removed through RO. Different
studies have revealed that the process of adsorption can be used as effective method
for removing the emerging contaminates from the water (Simeonov and Sargsyan
2008). These water wastes can be removed by using the techniques of adsorption.
Nanoparticles which have attracted a great deal of research interest in removal of
ECs release persistent free radicals (PFRs) with a half life of hours and days and
induce toxicity in microbes and plants. Hence, it can be concluded that,
• A single treatment technology cannot be the best strategy for the removal of ECs
from contaminated waters. It is imperative to examine the use of such coupled
systems that can bridge the dearth in a single technology for the removal of the
complex EC from the contaminated waters.
• Though phase-change processes are effective in wastewater treatment but are not
altogether successful in cases where low concentrations of EC are present in water.
Besides this, these procedures also do not have any permanent solution to the
problem due to generation of a concentrated phase after application of one type of
phase. Hence, these procedures can be used for concentration or pretreatment and
then successively coupled with further treatment(s) that are capable of degrading
ECs in aqueous phase.
• The biological processes utilized for scaling-up degradation of ECs do not identify
the microorganisms responsible for degradation; rather they only report their use
in the form of activated sludge which is capable of removing the contaminants.
Additionally, though these type of processes have been presented in the form of
well-organized treatment technologies but scaling-up studies do not confirm to
the experimental developments or detailed description of the processes tested.
399
difficult and tricky task. The conventional methods of treating wastewater are based
upon preliminary, primary, secondary, and tertiary treatment technologies which
involve the biological, physical, and chemical processes. The most frequently used
biological process of treating wastewater is by means of activated sludge. Although
the usual method of biological treatment is greatly efficient as it uses lesser space in
comparison with the non-conventional methods of treatment and its performance is
also independent of outdoor conditions, there are some drawbacks of these treatments
as well. These include constant high electrical energy requirements, the design and
maintenance, supervision, and overall the general cost of production that requires
extremely skilled workers. Similarly, the membranes which are used for the removal
of organic precursor matter are highly effective for the treatment of other emerging contaminants as well but here too; size exclusion is very significant and determines membrane capability. Both MF and UF are useful in removing pathogens from
wastewater but they are limited only to the removal of bacteria and allow viruses and
mycoplasms to pass through them. The membranes are highly sensitive to oxidative chemicals like nitric and sulfuric acids and also to peroxides and persulphates.
The processes of RO and NF have the broadest range of treatment ability and have
proved to be a good substitute of conventional treatment technologies. However,
both are diffusion and size exclusion controlled processes and require high degree
of pretreatment. NF removes harmful contaminates like pesticides and other organic
macromolecules but retains minerals that have to be removed through RO. Different
studies have revealed that the process of adsorption can be used as effective method
for removing the emerging contaminates from the water (Simeonov and Sargsyan
2008). These water wastes can be removed by using the techniques of adsorption.
Nanoparticles which have attracted a great deal of research interest in removal of
ECs release persistent free radicals (PFRs) with a half life of hours and days and
induce toxicity in microbes and plants. Hence, it can be concluded that,
• A single treatment technology cannot be the best strategy for the removal of ECs
from contaminated waters. It is imperative to examine the use of such coupled
systems that can bridge the dearth in a single technology for the removal of the
complex EC from the contaminated waters.
• Though phase-change processes are effective in wastewater treatment but are not
altogether successful in cases where low concentrations of EC are present in water.
Besides this, these procedures also do not have any permanent solution to the
problem due to generation of a concentrated phase after application of one type of
phase. Hence, these procedures can be used for concentration or pretreatment and
then successively coupled with further treatment(s) that are capable of degrading
ECs in aqueous phase.
• The biological processes utilized for scaling-up degradation of ECs do not identify
the microorganisms responsible for degradation; rather they only report their use
in the form of activated sludge which is capable of removing the contaminants.
Additionally, though these type of processes have been presented in the form of
well-organized treatment technologies but scaling-up studies do not confirm to
the experimental developments or detailed description of the processes tested.