decolorized 89% of anthraquinone colorant (Lambert et al. 2013). Although
electrocoagulation treatment has a series of benefits, some disadvantages are also
encountered, to name a few, the operational control, ineffectiveness on non-ionic
components, sludge production, and treatment costs.
17.4 Biological Methods
A series of physical and chemical techniques for dye remediation have been developed. However, none has satisfied the criteria of economic feasibility, technological
mastery, and environmental safety all at the same time. Biological treatments for dye
remediation have been proposed as cost-competitive and eco-friendly alternatives to
physical and chemical methods (Robinson et al. 2001; Vikrant et al. 2018). Biological treatments or so-called bioremediation utilize microorganisms or biocatalysts for
dye degradation and decolorization. Advantages and disadvantages and/or limitations of both microorganisms and biocatalysts are often compared in terms of
feasibility, efficiency, and working conditions (process control, the concentration
of dye, pH, and temperature).
Microorganism strains of various kinds and origins uptake or produce enzymes
that can biotransform or eliminate recalcitrant compounds from compounds (Xiang
et al. 2016; Vikrant et al. 2018; Kandelbauer and Guebitz 2005). The mechanism
behind the decolorization and degradation of dyes caused by microorganisms
involves the chemical breakdown of chromophore molecules (Ghosh et al. 2017;
Ito et al. 2016). Microorganisms that can decolorize or degrade dyes include bacteria
(Jadhav et al. 2010; Saranraj et al. 2010; Saratale et al. 2010; Mahmood et al. 2011;
Ponraj et al. 2011; Saratale et al. 2011; Alalewi and Jiang 2012; Buthelezi et al.
2012; Cheriaa et al. 2012; Khalid et al. 2012; Khouni et al. 2012; Sriram et al. 2013;
San et al. 2014; Singh et al. 2014; Lalnunhlimi and Krishnaswamy 2016), fungi
(Akar et al. 2009a, b; Couto 2009; Kaushik and Malik 2009; Prigione et al. 2009;
Yang et al. 2009; Diwaniyan et al. 2010; Vaithanomsat et al. 2010; Zhang et al.
2011; Chakraborty et al. 2013a; Daâssi et al. 2013; Hadibarata et al. 2013; Jebapriya
and Gnanadoss 2013; Almeida and Corso 2014; Ma et al. 2014; Rani et al. 2014),
algae (Bekçi et al. 2009; Chu et al. 2009; El-Sheekh et al. 2009; Khataee et al. 2010;
Lim et al. 2010; Rubín et al. 2010; Khataee et al. 2011; Cardoso et al. 2012; Esmaeli
et al. 2013; Khataee et al. 2013; Salima et al. 2013; San Keskin et al. 2015; Wang
et al. 2016), etc.
17.4.1 Dye Removal via Bacterial Strains
Bacteria have been extensively employed for dye degradation and decolorization,
especially for the azo dyes. Generally, bacteria decolorize azo dyes by cleaving azo
bonds either using electron donor moieties or enzymes such as laccase and azo
17 Methods for the Treatment of Wastewaters Containing Dyes and Pigments
635
electrocoagulation treatment has a series of benefits, some disadvantages are also
encountered, to name a few, the operational control, ineffectiveness on non-ionic
components, sludge production, and treatment costs.
17.4 Biological Methods
A series of physical and chemical techniques for dye remediation have been developed. However, none has satisfied the criteria of economic feasibility, technological
mastery, and environmental safety all at the same time. Biological treatments for dye
remediation have been proposed as cost-competitive and eco-friendly alternatives to
physical and chemical methods (Robinson et al. 2001; Vikrant et al. 2018). Biological treatments or so-called bioremediation utilize microorganisms or biocatalysts for
dye degradation and decolorization. Advantages and disadvantages and/or limitations of both microorganisms and biocatalysts are often compared in terms of
feasibility, efficiency, and working conditions (process control, the concentration
of dye, pH, and temperature).
Microorganism strains of various kinds and origins uptake or produce enzymes
that can biotransform or eliminate recalcitrant compounds from compounds (Xiang
et al. 2016; Vikrant et al. 2018; Kandelbauer and Guebitz 2005). The mechanism
behind the decolorization and degradation of dyes caused by microorganisms
involves the chemical breakdown of chromophore molecules (Ghosh et al. 2017;
Ito et al. 2016). Microorganisms that can decolorize or degrade dyes include bacteria
(Jadhav et al. 2010; Saranraj et al. 2010; Saratale et al. 2010; Mahmood et al. 2011;
Ponraj et al. 2011; Saratale et al. 2011; Alalewi and Jiang 2012; Buthelezi et al.
2012; Cheriaa et al. 2012; Khalid et al. 2012; Khouni et al. 2012; Sriram et al. 2013;
San et al. 2014; Singh et al. 2014; Lalnunhlimi and Krishnaswamy 2016), fungi
(Akar et al. 2009a, b; Couto 2009; Kaushik and Malik 2009; Prigione et al. 2009;
Yang et al. 2009; Diwaniyan et al. 2010; Vaithanomsat et al. 2010; Zhang et al.
2011; Chakraborty et al. 2013a; Daâssi et al. 2013; Hadibarata et al. 2013; Jebapriya
and Gnanadoss 2013; Almeida and Corso 2014; Ma et al. 2014; Rani et al. 2014),
algae (Bekçi et al. 2009; Chu et al. 2009; El-Sheekh et al. 2009; Khataee et al. 2010;
Lim et al. 2010; Rubín et al. 2010; Khataee et al. 2011; Cardoso et al. 2012; Esmaeli
et al. 2013; Khataee et al. 2013; Salima et al. 2013; San Keskin et al. 2015; Wang
et al. 2016), etc.
17.4.1 Dye Removal via Bacterial Strains
Bacteria have been extensively employed for dye degradation and decolorization,
especially for the azo dyes. Generally, bacteria decolorize azo dyes by cleaving azo
bonds either using electron donor moieties or enzymes such as laccase and azo
17 Methods for the Treatment of Wastewaters Containing Dyes and Pigments
635