Bioremediation Approaches for Degradation …
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In addition, these azo dyes alter the pH, reduce the dissolved oxygen level and
increase the BOD, chemical oxygen demand (COD) and create a grave hazard to
public health. Removal of colored dye substances from effluent is very critical and
crucial one, hence effluents from textile industries has been identified and considered
as a major pollutant among the all other pollutants (Bharathiraja et al. 2018).
1.4 Public Health Hazards/Health Impacts in Human Being
Most of the azo dyes are carcinogenic and mutagenic (Pinherio et al. 2004). The azo
dyes carcinogenic nature is due to the following mechanisms. First mechanism is
based on the release of aromatic amines from the azo dye by cleavage of azo bond.
These azo bonds covalently binds with DNA leads to form metabolically oxidized
state. Second mechanism is based on the free aromatic group from the azo dye,
without azo reduction to form metabolically oxidized form. Third mechanism is
based on the direct oxidation of azo bond with electrophilic diazonium salts of the
azo dyes (Bharathiraja et al., 2018).
Mutagenic nature of the azo dyes is based on the mutagenic compounds like
aromatic amines which includes chloro aniline, napthylamines etc. (Shivangi 2012).
In human health, presence of these azo dyes or its degraded products can cause
different disorders like allergies, hemorrhage, nausea, ulceration of skin infections
(skin irritation, dermatitis) and mucous membranes. Also, it can cause severe damage
to reproductive system, kidney, central nervous system, brain and liver. Different
organ cancers such as liver, spleen and bladder, in addition chromosomal deformities
in mammalian cells were also reported for these azo dyes (Chung and Chen 2009;
Ali 2010; Pooja et al. 2019).
2 Dye Removal (Wastewater Treatment) Techniques
Effluent treatment, disposal cost and regulations have made effluent treatment techniques play a critical role to protect the water resources as well as the environment.
The utmost important objective of the wastewater (effluent) treatment is to safe guard
the environment and to provide socio-economic concerns with public health (Metcalf
and Eddy 1991). The main principle of the wastewater treatment process is to remove
the pollutant from the effluent instead of destroying them. To design an appropriate
technique, understanding the nature of effluent is a fundamental one. Textile dye
effluent treatment techniques are shown in Fig. 2.
Each technique in the dye removal has its own limitations. Selection of an appropriate technique for the dye removal is based on the various factors. The factors
are
• Limits of the contaminants/pollutants in the final effluent from the plant must be
117
In addition, these azo dyes alter the pH, reduce the dissolved oxygen level and
increase the BOD, chemical oxygen demand (COD) and create a grave hazard to
public health. Removal of colored dye substances from effluent is very critical and
crucial one, hence effluents from textile industries has been identified and considered
as a major pollutant among the all other pollutants (Bharathiraja et al. 2018).
1.4 Public Health Hazards/Health Impacts in Human Being
Most of the azo dyes are carcinogenic and mutagenic (Pinherio et al. 2004). The azo
dyes carcinogenic nature is due to the following mechanisms. First mechanism is
based on the release of aromatic amines from the azo dye by cleavage of azo bond.
These azo bonds covalently binds with DNA leads to form metabolically oxidized
state. Second mechanism is based on the free aromatic group from the azo dye,
without azo reduction to form metabolically oxidized form. Third mechanism is
based on the direct oxidation of azo bond with electrophilic diazonium salts of the
azo dyes (Bharathiraja et al., 2018).
Mutagenic nature of the azo dyes is based on the mutagenic compounds like
aromatic amines which includes chloro aniline, napthylamines etc. (Shivangi 2012).
In human health, presence of these azo dyes or its degraded products can cause
different disorders like allergies, hemorrhage, nausea, ulceration of skin infections
(skin irritation, dermatitis) and mucous membranes. Also, it can cause severe damage
to reproductive system, kidney, central nervous system, brain and liver. Different
organ cancers such as liver, spleen and bladder, in addition chromosomal deformities
in mammalian cells were also reported for these azo dyes (Chung and Chen 2009;
Ali 2010; Pooja et al. 2019).
2 Dye Removal (Wastewater Treatment) Techniques
Effluent treatment, disposal cost and regulations have made effluent treatment techniques play a critical role to protect the water resources as well as the environment.
The utmost important objective of the wastewater (effluent) treatment is to safe guard
the environment and to provide socio-economic concerns with public health (Metcalf
and Eddy 1991). The main principle of the wastewater treatment process is to remove
the pollutant from the effluent instead of destroying them. To design an appropriate
technique, understanding the nature of effluent is a fundamental one. Textile dye
effluent treatment techniques are shown in Fig. 2.
Each technique in the dye removal has its own limitations. Selection of an appropriate technique for the dye removal is based on the various factors. The factors
are
• Limits of the contaminants/pollutants in the final effluent from the plant must be