Keywords Textile effluent · Biodegradation · Synthetic dye · Wastewater treatment
1 Introduction
Recently, the textile industries are gaining a remarkable economic significance
globally. The textile industry sector is diverse bodies which involve different
manufacturing elements with different kind of fibers for manufacturing various
fabrics having attractive properties. In the textile industries, more than 8000 chemical compounds are used annually for preparing 400 billion m
2 of fabric around the
world. During the manufacturing process of textile fabrics, different chemical
treatments such as sizing, scoring, mercerizing, coloring, printing, and finishing
are carried out (Alkaya et al. 2012). Wet processing is a common method which
utilizes huge quantities of water and various chemical compounds for ameliorating
the properties of auxiliary textiles, such as fabric texture, serviceability, and
durability.
As a primary wet processing step, starch content is removed from the cloth by
“desizing.” After desizing, the fabric may contain oils, fats, waxes, seed pieces, leaf
particles, natural coloring matters, etc. The presence of oils, fats, and waxes is
considerably influencing for determining the hydrophobic characteristics of the
cloth. So, these compounds are liable to affect the cloth absorbance that leads to
the subsequent process of improper dyeing, printing, and finishing. Hence, eradication of these impurities from the fabric is much important and is called scouring
(or) Kier boiling. The removal of natural coloring material is carried out by the
technique called bleaching. Luster of the fabric can be boosted through mercerization. Dyeing is a very important process for adding colors to the fabric. During the
dyeing process, different synthetic dyes, curing agents, bleaches, solvents, and
heavy metal enriched detergents are used.
The surplus hazardous chemicals, such as polyvinyl chloride, chlorine, benzidine,
and toluidine, involved in the different steps on textile processing are the key factor
for toxic emissions from the textile mills (Choudhury 2017). Additionally, formaldehyde, lead, and mercury are other harmful and cancer-causing agents, which are
used in routine textile operations. The release of these untreated toxics would
contaminate rivers and groundwater reservoirs. Over 10,000 different dyes and
pigments are expected to be used in textile industry. Based on the current statistics,
more than 7105 tons of synthetic colors are produced annually (Hasanbeigi and Price
2015). Approximately 40% of these dyes use organic volatile chlorine, carcinogen.
Such organic matter present in the textile effluents needs a great concern of wastewater treatment, since they respond with many disinfectants, in specific chlorine
(Brüschweiler and Merlot 2017).
The chemical pollutants from the textile wet processing can also pose a serious
safety risk to the environment. There are different schematic approaches that have
been proposed for controlling the textile wet processes to meet a better environment
and to protect the ecosystem. Modern management for the treatment of waste
196
K. Rajan et al.
1 Introduction
Recently, the textile industries are gaining a remarkable economic significance
globally. The textile industry sector is diverse bodies which involve different
manufacturing elements with different kind of fibers for manufacturing various
fabrics having attractive properties. In the textile industries, more than 8000 chemical compounds are used annually for preparing 400 billion m
2 of fabric around the
world. During the manufacturing process of textile fabrics, different chemical
treatments such as sizing, scoring, mercerizing, coloring, printing, and finishing
are carried out (Alkaya et al. 2012). Wet processing is a common method which
utilizes huge quantities of water and various chemical compounds for ameliorating
the properties of auxiliary textiles, such as fabric texture, serviceability, and
durability.
As a primary wet processing step, starch content is removed from the cloth by
“desizing.” After desizing, the fabric may contain oils, fats, waxes, seed pieces, leaf
particles, natural coloring matters, etc. The presence of oils, fats, and waxes is
considerably influencing for determining the hydrophobic characteristics of the
cloth. So, these compounds are liable to affect the cloth absorbance that leads to
the subsequent process of improper dyeing, printing, and finishing. Hence, eradication of these impurities from the fabric is much important and is called scouring
(or) Kier boiling. The removal of natural coloring material is carried out by the
technique called bleaching. Luster of the fabric can be boosted through mercerization. Dyeing is a very important process for adding colors to the fabric. During the
dyeing process, different synthetic dyes, curing agents, bleaches, solvents, and
heavy metal enriched detergents are used.
The surplus hazardous chemicals, such as polyvinyl chloride, chlorine, benzidine,
and toluidine, involved in the different steps on textile processing are the key factor
for toxic emissions from the textile mills (Choudhury 2017). Additionally, formaldehyde, lead, and mercury are other harmful and cancer-causing agents, which are
used in routine textile operations. The release of these untreated toxics would
contaminate rivers and groundwater reservoirs. Over 10,000 different dyes and
pigments are expected to be used in textile industry. Based on the current statistics,
more than 7105 tons of synthetic colors are produced annually (Hasanbeigi and Price
2015). Approximately 40% of these dyes use organic volatile chlorine, carcinogen.
Such organic matter present in the textile effluents needs a great concern of wastewater treatment, since they respond with many disinfectants, in specific chlorine
(Brüschweiler and Merlot 2017).
The chemical pollutants from the textile wet processing can also pose a serious
safety risk to the environment. There are different schematic approaches that have
been proposed for controlling the textile wet processes to meet a better environment
and to protect the ecosystem. Modern management for the treatment of waste
196
K. Rajan et al.