176
R. Sukanya Devi et al.
Table 1 Various treatment processes for cotton textile process effluents with their merits and
demerits
Process
Advantages
Disadvantages
References
Coagulation/flocculation Removal of insoluble
dyes
Fouling due to sludge
generation
[10]
Adsorption using
activated carbon
Control over suspended
solids and organic
substances
Cost of activated carbon
used
[11]
Biodegradation
Effective elimination of
oxidizable substances
Poor biodegradability of
dyes
[12]
Ozonation
Effective dye
decolourization
No significance in terms
of the COD removal; cost
of ozonation systems
[13]
Electrochemical
oxidation process
Well suited for different
volumes and pollution
loads
Excess iron hydroxide
sludge formation
[14, 15]
Ultra-filtration and micro
filtration
Low pressure
Pre-treatment for NF or
RO and reduce fouling on
NF and RO
[16]
Nano filtration
Effective filtration of low
molecular weight organic
compounds and divalent
ions from monovalent
salts
Not efficient for
separation of monovalent
salts, fouling
[17–20]
Reverse osmosis
Effective removal of
mineral salts and
hydrolyses reactive dyes
and other chemical
auxiliaries
Requires high pressure,
fouling
[21–23]
wastewater due to the formation of hydroxyl radicals in the presence of organic matter
in high concentration. Introduction of a homogeneous (dissolved ions as Fe
2+ , Mn
2+ ,
Cu
2+ ) or heterogeneous (i.e. MnO 2 , Ni 2 O 3 , Fe 2 O 3 , CuO, Al 2 O 3 , TiO 2 ) catalyst can
serve as an opportunity to accelerate the ozonation reaction and the decomposition
of the target compounds [26]. For instance, it is showed that the combined ability
of ozone and a catalyst/adsorbent shows high potential in elimination of dyes from
wastewater. These AOPs used for the removal of dyes from wastewater effluents
are conducted on industrial wastewater treatment plants effluents and designed as
end-of-the-pipe solution.
Table 2 shows the characteristics of the dye bath and wash water effluent (raw
effluent and before/after each process) (26). The TDS levels at RO reject and the
ME evaporator inlet/concentrate are so intense and require an alternate methods
to reduce the pollutant. Many new treatment methods are suggested and are under
laboratory trials. One such process is the advanced oxidation treatment, which has
a promising results, and some processes are already in use. Advanced oxidation
processes are wide range of technologies which are used/investigated mainly to
R. Sukanya Devi et al.
Table 1 Various treatment processes for cotton textile process effluents with their merits and
demerits
Process
Advantages
Disadvantages
References
Coagulation/flocculation Removal of insoluble
dyes
Fouling due to sludge
generation
[10]
Adsorption using
activated carbon
Control over suspended
solids and organic
substances
Cost of activated carbon
used
[11]
Biodegradation
Effective elimination of
oxidizable substances
Poor biodegradability of
dyes
[12]
Ozonation
Effective dye
decolourization
No significance in terms
of the COD removal; cost
of ozonation systems
[13]
Electrochemical
oxidation process
Well suited for different
volumes and pollution
loads
Excess iron hydroxide
sludge formation
[14, 15]
Ultra-filtration and micro
filtration
Low pressure
Pre-treatment for NF or
RO and reduce fouling on
NF and RO
[16]
Nano filtration
Effective filtration of low
molecular weight organic
compounds and divalent
ions from monovalent
salts
Not efficient for
separation of monovalent
salts, fouling
[17–20]
Reverse osmosis
Effective removal of
mineral salts and
hydrolyses reactive dyes
and other chemical
auxiliaries
Requires high pressure,
fouling
[21–23]
wastewater due to the formation of hydroxyl radicals in the presence of organic matter
in high concentration. Introduction of a homogeneous (dissolved ions as Fe
2+ , Mn
2+ ,
Cu
2+ ) or heterogeneous (i.e. MnO 2 , Ni 2 O 3 , Fe 2 O 3 , CuO, Al 2 O 3 , TiO 2 ) catalyst can
serve as an opportunity to accelerate the ozonation reaction and the decomposition
of the target compounds [26]. For instance, it is showed that the combined ability
of ozone and a catalyst/adsorbent shows high potential in elimination of dyes from
wastewater. These AOPs used for the removal of dyes from wastewater effluents
are conducted on industrial wastewater treatment plants effluents and designed as
end-of-the-pipe solution.
Table 2 shows the characteristics of the dye bath and wash water effluent (raw
effluent and before/after each process) (26). The TDS levels at RO reject and the
ME evaporator inlet/concentrate are so intense and require an alternate methods
to reduce the pollutant. Many new treatment methods are suggested and are under
laboratory trials. One such process is the advanced oxidation treatment, which has
a promising results, and some processes are already in use. Advanced oxidation
processes are wide range of technologies which are used/investigated mainly to