licheniformis and mixed with CaCl 2 showed significant improvement in drinking
water treatment. At variable temperature, from 4 to 25
C, the effectiveness of EPS
on drinking water treatment was also reported. The drinking water COD and
turbidity removal from the water were noticed as 61.2% and 95.6%, respectively.
Based on the experimental study by Li et al. (2009), the EPSs synthesized by
Bacillus licheniformis were safe, and it is recommended for drinking water treatment. It can remove both gram-positive (S. aureus and Streptococcus faecalis) and
gram-negative (Escherichia coli and Klebsiella oxytoca) bacteria from river water up
to 98.3%. In substitution of alum study, Buthelezi et al. (2009) reported that bacterial
EPS is a potential alternative to alum and it acts as the best organic coagulant in the
river water treatment.
2.5 Wastewater Flocculation and Setting
Flocculation and setting is the main unit operation process still practiced in wastewater treatment process. Still, both conventional and advanced oxidation processes
are also implemented to speed up flocculation and settling process. One of the
emerging areas is usage of microbes and/or microbial products as flocculants in
wastewater treatments. Exopolysaccharides from Serratia ficaria were showed to be
potentially used in wastewater treatments and industries such as brewery, soy sauce
brewing, meat processing, pulp and paper, etc. (Gong et al. 2008). For example, EPS
is used to treat swine wastewater with turbidity (91%) and COD (42%) of removal
efficiency, and these percentages of removal are better than the polyaluminum
chloride (Zhang et al. 2012). Lian et al. (2008) reported that the EPS from Bacillus
mucilaginosus is most commonly used to treat municipal, brewage, and pharmaceutical wastewater. Consortium and their effectiveness are also studied to check their
potential removal efficiency. The EPS from Staphylococcus sp. and Pseudomonas
sp. applied in treatment of indigotin printing and dyeing wastewater, and it was
reported that COD removal percentage was around 80 (Zhang et al. 2007). Similarly,
polysaccharide-based EPS from Paenibacillus elgii (B69) showed the wastewater
COD (68%) and turbidity (83%) removal potential (Li et al. 2013). Based on
literature survey, majority of the reports indicated that the application of EPS in
wastewater treatment demonstrated at laboratory scale.
2.6 Dewatering from Sludge
In the area of sludge dewatering process, particularly in mechanical sludge
dewatering process, huge quantities of chemically derived polymers are mostly
used. In wastewater treatment process, it will become highly expensive (More
et al. 2010). When we are using exopolysaccharides (EPS) in sludge dewatering
process, the concentration, type, and characteristics of EPS are very important
7 Recent Trends in Application of Bacterial Polymers to Mitigate Organic and. . .
143
water treatment. At variable temperature, from 4 to 25
C, the effectiveness of EPS
on drinking water treatment was also reported. The drinking water COD and
turbidity removal from the water were noticed as 61.2% and 95.6%, respectively.
Based on the experimental study by Li et al. (2009), the EPSs synthesized by
Bacillus licheniformis were safe, and it is recommended for drinking water treatment. It can remove both gram-positive (S. aureus and Streptococcus faecalis) and
gram-negative (Escherichia coli and Klebsiella oxytoca) bacteria from river water up
to 98.3%. In substitution of alum study, Buthelezi et al. (2009) reported that bacterial
EPS is a potential alternative to alum and it acts as the best organic coagulant in the
river water treatment.
2.5 Wastewater Flocculation and Setting
Flocculation and setting is the main unit operation process still practiced in wastewater treatment process. Still, both conventional and advanced oxidation processes
are also implemented to speed up flocculation and settling process. One of the
emerging areas is usage of microbes and/or microbial products as flocculants in
wastewater treatments. Exopolysaccharides from Serratia ficaria were showed to be
potentially used in wastewater treatments and industries such as brewery, soy sauce
brewing, meat processing, pulp and paper, etc. (Gong et al. 2008). For example, EPS
is used to treat swine wastewater with turbidity (91%) and COD (42%) of removal
efficiency, and these percentages of removal are better than the polyaluminum
chloride (Zhang et al. 2012). Lian et al. (2008) reported that the EPS from Bacillus
mucilaginosus is most commonly used to treat municipal, brewage, and pharmaceutical wastewater. Consortium and their effectiveness are also studied to check their
potential removal efficiency. The EPS from Staphylococcus sp. and Pseudomonas
sp. applied in treatment of indigotin printing and dyeing wastewater, and it was
reported that COD removal percentage was around 80 (Zhang et al. 2007). Similarly,
polysaccharide-based EPS from Paenibacillus elgii (B69) showed the wastewater
COD (68%) and turbidity (83%) removal potential (Li et al. 2013). Based on
literature survey, majority of the reports indicated that the application of EPS in
wastewater treatment demonstrated at laboratory scale.
2.6 Dewatering from Sludge
In the area of sludge dewatering process, particularly in mechanical sludge
dewatering process, huge quantities of chemically derived polymers are mostly
used. In wastewater treatment process, it will become highly expensive (More
et al. 2010). When we are using exopolysaccharides (EPS) in sludge dewatering
process, the concentration, type, and characteristics of EPS are very important
7 Recent Trends in Application of Bacterial Polymers to Mitigate Organic and. . .
143