excellent durability. Despite this, a large discharge of colored contaminated effluent
has been found in different textile industries. Such effluents have notable color
concentration greater than 1 mg/L (Hassan and Carr 2018). The presence of ammonia, aniline, vat dyes, nitroglycerin, sodium bicarbonate, soaps, chloride salts, and
heavy metals, such as bronze, arsenic, gold, zinc carbonate, Hg, nickel, and cobalt
chloride hexahydrate, and other auxiliary chemicals, which together present in the
effluents from coloration process, makes it as extremely toxic. Methanol-based dye
fixing agents, cationic-based softeners, and nonrecyclable coloring substances may
also be the other dangerous chemicals found in that wastewaters (Khatri et al. 2015).
Besides dyes, diverse auxiliary chemical compounds are used, which additionally
end up within the waste water. Color and numerous auxiliaries, including organic
acids, fixing agents, defoamers, oxidizing/reducing agents, and diluents, are regular
pollution that are generated in the course of the dyeing step. Quite a big amount of
dyes leaves the system in an unfixed state. The exact amount and the form of
pollution rely on the dyes and the procedure used (Broadbent 2001).
The different steps in printing and coloring unit include pretreatment, coloring,
printing, and finishing. These processes release huge quantities of starch, waxes,
carboxyl methyl cellulose (CMC), polyvinyl alcohol, wetting agents, hydrochloric
acid, Cl 2 , NaOH, H 2 O 2 , emulsifiers, sodium silicate, potassium sulfate, and linters.
These contaminants are unique outcome from the printing and dyeing unit effluent.
They contain high starch, elevated dissolved solids (DS), high BOD, low suspended
solids, and moderate level of heavy metals and seem to be oily and slightly alkaline
(Hardin 2010). In some dyeing processes, around 75% of the total used salts end up
in the generated wastewaters. Printing is a coloring operation, as is dyeing, but it is a
“localized” coloring that typically covers only a specific section of the textile
portion. Printing is normally achieved by using thickened dyes or pigment pastes
on the surface, in accordance with the color design (Hashemi Sanatgar et al. 2017).
During this process, some unused printing paste is discarded that can lead for water
contamination. In order to minimize this risk, the printing paste can also be quickly
extracted with smaller volume lost. The printed paste absorption can be increased
using additional energy that can minimize the discarded pollutants. Recently,
researchers show great interest in color control due to their toxic and genotoxic
effects on living organisms as they have been recognized as carcinogenic substances,
such as benzidines and other aromatic compounds (Bisschops and Henri 2003).
2.3 Finishing Process
Finishing involves one or more processes performed on fiber, yarn, or textile to
enhance their behavioral quality, in specific, durability. For this, many chemicals are
used in padding machines that move the substance under a roller guide and between
two padding sheets. Before the textiles are transferred to a steaming or washing and
drying machine, excess liquid is drained from the sheets (Savin and Butnaru 2008).
This process is achieved by the fabric with a certain amount of UV-protective
200
K. Rajan et al.
has been found in different textile industries. Such effluents have notable color
concentration greater than 1 mg/L (Hassan and Carr 2018). The presence of ammonia, aniline, vat dyes, nitroglycerin, sodium bicarbonate, soaps, chloride salts, and
heavy metals, such as bronze, arsenic, gold, zinc carbonate, Hg, nickel, and cobalt
chloride hexahydrate, and other auxiliary chemicals, which together present in the
effluents from coloration process, makes it as extremely toxic. Methanol-based dye
fixing agents, cationic-based softeners, and nonrecyclable coloring substances may
also be the other dangerous chemicals found in that wastewaters (Khatri et al. 2015).
Besides dyes, diverse auxiliary chemical compounds are used, which additionally
end up within the waste water. Color and numerous auxiliaries, including organic
acids, fixing agents, defoamers, oxidizing/reducing agents, and diluents, are regular
pollution that are generated in the course of the dyeing step. Quite a big amount of
dyes leaves the system in an unfixed state. The exact amount and the form of
pollution rely on the dyes and the procedure used (Broadbent 2001).
The different steps in printing and coloring unit include pretreatment, coloring,
printing, and finishing. These processes release huge quantities of starch, waxes,
carboxyl methyl cellulose (CMC), polyvinyl alcohol, wetting agents, hydrochloric
acid, Cl 2 , NaOH, H 2 O 2 , emulsifiers, sodium silicate, potassium sulfate, and linters.
These contaminants are unique outcome from the printing and dyeing unit effluent.
They contain high starch, elevated dissolved solids (DS), high BOD, low suspended
solids, and moderate level of heavy metals and seem to be oily and slightly alkaline
(Hardin 2010). In some dyeing processes, around 75% of the total used salts end up
in the generated wastewaters. Printing is a coloring operation, as is dyeing, but it is a
“localized” coloring that typically covers only a specific section of the textile
portion. Printing is normally achieved by using thickened dyes or pigment pastes
on the surface, in accordance with the color design (Hashemi Sanatgar et al. 2017).
During this process, some unused printing paste is discarded that can lead for water
contamination. In order to minimize this risk, the printing paste can also be quickly
extracted with smaller volume lost. The printed paste absorption can be increased
using additional energy that can minimize the discarded pollutants. Recently,
researchers show great interest in color control due to their toxic and genotoxic
effects on living organisms as they have been recognized as carcinogenic substances,
such as benzidines and other aromatic compounds (Bisschops and Henri 2003).
2.3 Finishing Process
Finishing involves one or more processes performed on fiber, yarn, or textile to
enhance their behavioral quality, in specific, durability. For this, many chemicals are
used in padding machines that move the substance under a roller guide and between
two padding sheets. Before the textiles are transferred to a steaming or washing and
drying machine, excess liquid is drained from the sheets (Savin and Butnaru 2008).
This process is achieved by the fabric with a certain amount of UV-protective
200
K. Rajan et al.