recovery followed by aerobic polishing, and (iv) reverse osmosis. Out of the four
routes, anaerobic treatment has been considered as the most attractive first-step
treatment technique for the SW due to its reputation as an eco-friendly and
low-cost technique besides its methane production potential (Oller et al. 2011). In
addition, anaerobic treatment is preferred due to fact that a significant component of
SW is biodegradable. The anaerobic treatment is reported to remove about 40–50%
COD and 60–65% BOD from the SW (Arimi et al. 2015). The color of SW converts
darker with higher TDS after anaerobic digestion due to complexation of organic and
inorganic pollutants present in the SW. This means that SW after anaerobic treatment still contains high organic and inorganic load and it is not safe for discharge
into the environment (Chandra and Kumar 2017a; Chandra et al. 2018a).
The SW received after anaerobic treatment (methanogenesis) is called postmethanated distillery effluent (PMDE) or biomethanated distillery effluent
(BMDE). PMDE is characterized by an extremely higher level of BOD, COD,
TDS, TKN, SO 3
2À
, Na
+
, and PO 4
3À , with alkaline pH and dark-brown color. In
addition, PMDE retains a high amount of various toxic HMs, viz., Ni, Mn, Fe, Zn,
Cu, Pb, and Cd along with melanoidins and various recalcitrant/refractory organic
pollutants (ROPs) (Bharagava and Chandra 2010a; Chandra et al. 2012). Moreover,
Indian distilleries produce approximately 1500 tons of distillery sludge per day
during anaerobic treatment of SW (Kansal et al. 1998) which is characterized by
high organic matter (OM), phenolics, SO 3
2À , Na
+
, PO 4
3À
, and HMs along with
melanoidins and various androgenic and mutagenic compounds (Chandra et al.
2018b; Chandra and Kumar 2017a). Satyawali and Balakrishnan (2008) reported
that anaerobic treatment does not result in effective color removal from SW. When
the untreated or partially treated melanoidins containing SW or PMDE are released
into water bodies, they damage aquatic ecosystem by reducing the sunlight penetration power and finally the photosynthetic activities and dissolved oxygen content,
whereas in agricultural soil it causes depletion of vegetation by reducing the soil
alkalinity and Mn availability and inhibiting the seed germination (Chowdhary et al.
2017) (Fig. 20.1). Therefore, it is essential to study additional pre- or post-treatment
methods to remove color and recalcitrant organic compounds from PMDE. Fig. 20.1
shows the environmental pollution caused by discharged SW and PMDE.
The complexity of distillery effluent makes not easy for the development of
efficient tertiary treatment technologies for removal of color and toxic androgenic
and mutagenic compounds prior to its disposal into the environment. For instance,
Indian distilleries have been directed by the Ministry of Environment, Forest, and
Climate Change, Govt. of India, to achieve zero liquid discharge into the surface
water bodies from December 2005. In many regions of India, distillery industries
dilute the PMDE by mixing with raw water prior to discharge in the environment in
order to meet the set effluent disposal standard. This dilution of PMDE even though
accepted in some regions of India is of great environmental concern as it does not
reduce the complete pollution load of the PMDE (Chaudhari et al. 2007). Various
physicochemical methods such as membrane filtration (Kumar et al. 2008), flocculation (Liang et al. 2009a), coagulation (Liang et al. 2009b), adsorption (Onyango
et al. 2011), ozone oxidation (Kim et al. 1985), and ultraviolet/hydrogen peroxide
20 Bioremediation of Melanoidins Containing Distillery Waste for. . .
497
routes, anaerobic treatment has been considered as the most attractive first-step
treatment technique for the SW due to its reputation as an eco-friendly and
low-cost technique besides its methane production potential (Oller et al. 2011). In
addition, anaerobic treatment is preferred due to fact that a significant component of
SW is biodegradable. The anaerobic treatment is reported to remove about 40–50%
COD and 60–65% BOD from the SW (Arimi et al. 2015). The color of SW converts
darker with higher TDS after anaerobic digestion due to complexation of organic and
inorganic pollutants present in the SW. This means that SW after anaerobic treatment still contains high organic and inorganic load and it is not safe for discharge
into the environment (Chandra and Kumar 2017a; Chandra et al. 2018a).
The SW received after anaerobic treatment (methanogenesis) is called postmethanated distillery effluent (PMDE) or biomethanated distillery effluent
(BMDE). PMDE is characterized by an extremely higher level of BOD, COD,
TDS, TKN, SO 3
2À
, Na
+
, and PO 4
3À , with alkaline pH and dark-brown color. In
addition, PMDE retains a high amount of various toxic HMs, viz., Ni, Mn, Fe, Zn,
Cu, Pb, and Cd along with melanoidins and various recalcitrant/refractory organic
pollutants (ROPs) (Bharagava and Chandra 2010a; Chandra et al. 2012). Moreover,
Indian distilleries produce approximately 1500 tons of distillery sludge per day
during anaerobic treatment of SW (Kansal et al. 1998) which is characterized by
high organic matter (OM), phenolics, SO 3
2À , Na
+
, PO 4
3À
, and HMs along with
melanoidins and various androgenic and mutagenic compounds (Chandra et al.
2018b; Chandra and Kumar 2017a). Satyawali and Balakrishnan (2008) reported
that anaerobic treatment does not result in effective color removal from SW. When
the untreated or partially treated melanoidins containing SW or PMDE are released
into water bodies, they damage aquatic ecosystem by reducing the sunlight penetration power and finally the photosynthetic activities and dissolved oxygen content,
whereas in agricultural soil it causes depletion of vegetation by reducing the soil
alkalinity and Mn availability and inhibiting the seed germination (Chowdhary et al.
2017) (Fig. 20.1). Therefore, it is essential to study additional pre- or post-treatment
methods to remove color and recalcitrant organic compounds from PMDE. Fig. 20.1
shows the environmental pollution caused by discharged SW and PMDE.
The complexity of distillery effluent makes not easy for the development of
efficient tertiary treatment technologies for removal of color and toxic androgenic
and mutagenic compounds prior to its disposal into the environment. For instance,
Indian distilleries have been directed by the Ministry of Environment, Forest, and
Climate Change, Govt. of India, to achieve zero liquid discharge into the surface
water bodies from December 2005. In many regions of India, distillery industries
dilute the PMDE by mixing with raw water prior to discharge in the environment in
order to meet the set effluent disposal standard. This dilution of PMDE even though
accepted in some regions of India is of great environmental concern as it does not
reduce the complete pollution load of the PMDE (Chaudhari et al. 2007). Various
physicochemical methods such as membrane filtration (Kumar et al. 2008), flocculation (Liang et al. 2009a), coagulation (Liang et al. 2009b), adsorption (Onyango
et al. 2011), ozone oxidation (Kim et al. 1985), and ultraviolet/hydrogen peroxide
20 Bioremediation of Melanoidins Containing Distillery Waste for. . .
497