Microalgae
Recently, the use of microalgae for bioremediation textile wastewaters has drawn a
huge interest due to their excellent role in carbon dioxide fixation. The culture of
vulgaris in the textile waste effluent showed that these microalgae can be used to
extract color and reduce COD. Additionally, the biomass from algae has great value
as feedstock for the production of biofuel (Huang et al. 2010). Such kind of
bioremediation with microalgae can be an ideal for environmental sustainability
(Ellis et al. 2012, Chandran et al. 2002). Bioremediation using microalgae shows
several advantages in terms of cost-effectiveness and easy scale-up. Using
microalgae, bioremediation, and CO 2 mitigation can be carried out simultaneously;
also, high-added-value molecules can be biosynthesized.
Aerobic Biodegradation
The toxic compounds present in the textile wastewaters can be decomposed into
harmless inorganic solids by the bacterial catalysis being involved during the
biodegradation treatment. Generally, bacteria can be categorized into aerobic, anaerobic, and facultative bacteria based on the oxygen requirement. The aerobic bacteria
purify wastewaters, by decomposing it, and reduce unpleasant odors with the help of
aerobic and facultative bacteria. The aerobic treatment process is performed by an
activated sludge and biofilm process (Robinson et al. 2001). Activated sludge
process (ASP) is a widely used biological process to treat textile wastewater effluent
treatment. In this process, a kind of colony comprising deferent microorganisms that
have high level of biosorption and decay capacity, colloquially called as “activated
sludge.” Such kind of biological treatment eliminates the organic matter, residual
solids, and non-settable solids. Here, microorganisms, particularly bacteria, are
employed. ASP works based on the principle of microorganisms that forms a colony
by growing and clumping together. During ASP, the microorganisms form agglomerated organic materials and settle down to the bottom of the tank, which creates a
clear liquid free from suspended solids. The most commonly used activated sludge
methods are the oxidation ditch and the sequenced batch reactor (SBR) process
(Mani and Bharagava 2018). A biofilm is a biological effluent treatment process that
involves microorganisms, which are attaching to the outer edge of the fixed object to
develop a film, which allows purifying the swirling effluent. The biofilm mechanisms are mainly carried out at biological contact oxidation, revolving biological
contractors, and fluidized bioreactor (Dos Santos et al. 2007).
Anaerobic Biodegradation
Anaerobic degradation occurs when the medium contains no oxygen or very low
oxygen. This procedure also degrades some sort of waste in the effluents. So, the
substance can be forecasted with low water solubility, which may be subject to
10 A Harmless Approach on Textile Effluent Detoxification: Bioremediation and. . .
209
Recently, the use of microalgae for bioremediation textile wastewaters has drawn a
huge interest due to their excellent role in carbon dioxide fixation. The culture of
vulgaris in the textile waste effluent showed that these microalgae can be used to
extract color and reduce COD. Additionally, the biomass from algae has great value
as feedstock for the production of biofuel (Huang et al. 2010). Such kind of
bioremediation with microalgae can be an ideal for environmental sustainability
(Ellis et al. 2012, Chandran et al. 2002). Bioremediation using microalgae shows
several advantages in terms of cost-effectiveness and easy scale-up. Using
microalgae, bioremediation, and CO 2 mitigation can be carried out simultaneously;
also, high-added-value molecules can be biosynthesized.
Aerobic Biodegradation
The toxic compounds present in the textile wastewaters can be decomposed into
harmless inorganic solids by the bacterial catalysis being involved during the
biodegradation treatment. Generally, bacteria can be categorized into aerobic, anaerobic, and facultative bacteria based on the oxygen requirement. The aerobic bacteria
purify wastewaters, by decomposing it, and reduce unpleasant odors with the help of
aerobic and facultative bacteria. The aerobic treatment process is performed by an
activated sludge and biofilm process (Robinson et al. 2001). Activated sludge
process (ASP) is a widely used biological process to treat textile wastewater effluent
treatment. In this process, a kind of colony comprising deferent microorganisms that
have high level of biosorption and decay capacity, colloquially called as “activated
sludge.” Such kind of biological treatment eliminates the organic matter, residual
solids, and non-settable solids. Here, microorganisms, particularly bacteria, are
employed. ASP works based on the principle of microorganisms that forms a colony
by growing and clumping together. During ASP, the microorganisms form agglomerated organic materials and settle down to the bottom of the tank, which creates a
clear liquid free from suspended solids. The most commonly used activated sludge
methods are the oxidation ditch and the sequenced batch reactor (SBR) process
(Mani and Bharagava 2018). A biofilm is a biological effluent treatment process that
involves microorganisms, which are attaching to the outer edge of the fixed object to
develop a film, which allows purifying the swirling effluent. The biofilm mechanisms are mainly carried out at biological contact oxidation, revolving biological
contractors, and fluidized bioreactor (Dos Santos et al. 2007).
Anaerobic Biodegradation
Anaerobic degradation occurs when the medium contains no oxygen or very low
oxygen. This procedure also degrades some sort of waste in the effluents. So, the
substance can be forecasted with low water solubility, which may be subject to
10 A Harmless Approach on Textile Effluent Detoxification: Bioremediation and. . .
209