2.8 Landfill Leachate Treatment
In the era of landfill leachate treatment, bacterial polymers play a vital role in the
removal of humic acids from landfill. Rhizomonas sp. was used to extract
exopolysaccharides (EPS) instead of alum for the removal of humic acids in
synthetic solutions. Apart from these EPS showed significant reduction of chemical oxygen demand (COD) up to 45% during landfill leachate treatment
(Zouboulis et al. 2004). Similarly, other reports showed that optimum EPS dosage
of per liter was 20 mg and pH range from 7À7.5 gives better result and it will go up
to 85% of humic acid removal by EPS-producing bacterial species. Newly
established (<5-year-old) landfill’s leachate are abundant source of organic matter;
these can be harnessed (as raw materials) by bacteria for EPS generation (Fusconi
et al. 2006; Zouboulis et al. 2004).
2.9 Soil Remediation and Reclamation
Since the past two decades, several studies were reported particularly in the remediation of xenobiotic by the development of biofilm reactors (Singh et al. 2006). The
formation of biofilms take place by the action of microbial communities and
exopolysaccharides from microbes. This kind of microbial biofilms has shown
higher rate of degradation of recalcitrant compounds as well as these microbial
biofilms have shown the immobilization of these recalcitrant compounds via EPS
matrix (Singh et al. 2006). Similarly, the EPS matrix is used to reduce migration of
solids in soil during runoff water; it reduces heavy metal transport, and particularly it
stabilizes soil structure and texture and reduces formation of dust during soil
pollution process (Gerbersdorf et al. 2008).
EPS are obtained from different single pure and/or mixed cultures, and these
exopolysaccharides are obtained via aerobic fermentation process. After production, EPS are directly separated from the production media and extracted as noncross-linking material. These nonreactive (non-cross-linking) EPS, directly
applied to the soil, (mix the soil with dry EPS), and, water added to form a gel
within the soil matrix, (soil molecules bind with EPS and form a soil-EPS intermediates). In particular, bacterial EPS directly acts as a cohesive force in the
formation of surface erosion resistance in soil and their sediments (Droppo
2009). For example, cyanobacteria are previously used and applied for promoting
this kind of soil adhesion studies in arid regions (Prasanna et al. 2008). Soil
modification using these EPS-rich natural products gives pathway to understand
the concept of bio-geo-civil engineering (Ivanov and Chu 2008).
7 Recent Trends in Application of Bacterial Polymers to Mitigate Organic and. . .
145
In the era of landfill leachate treatment, bacterial polymers play a vital role in the
removal of humic acids from landfill. Rhizomonas sp. was used to extract
exopolysaccharides (EPS) instead of alum for the removal of humic acids in
synthetic solutions. Apart from these EPS showed significant reduction of chemical oxygen demand (COD) up to 45% during landfill leachate treatment
(Zouboulis et al. 2004). Similarly, other reports showed that optimum EPS dosage
of per liter was 20 mg and pH range from 7À7.5 gives better result and it will go up
to 85% of humic acid removal by EPS-producing bacterial species. Newly
established (<5-year-old) landfill’s leachate are abundant source of organic matter;
these can be harnessed (as raw materials) by bacteria for EPS generation (Fusconi
et al. 2006; Zouboulis et al. 2004).
2.9 Soil Remediation and Reclamation
Since the past two decades, several studies were reported particularly in the remediation of xenobiotic by the development of biofilm reactors (Singh et al. 2006). The
formation of biofilms take place by the action of microbial communities and
exopolysaccharides from microbes. This kind of microbial biofilms has shown
higher rate of degradation of recalcitrant compounds as well as these microbial
biofilms have shown the immobilization of these recalcitrant compounds via EPS
matrix (Singh et al. 2006). Similarly, the EPS matrix is used to reduce migration of
solids in soil during runoff water; it reduces heavy metal transport, and particularly it
stabilizes soil structure and texture and reduces formation of dust during soil
pollution process (Gerbersdorf et al. 2008).
EPS are obtained from different single pure and/or mixed cultures, and these
exopolysaccharides are obtained via aerobic fermentation process. After production, EPS are directly separated from the production media and extracted as noncross-linking material. These nonreactive (non-cross-linking) EPS, directly
applied to the soil, (mix the soil with dry EPS), and, water added to form a gel
within the soil matrix, (soil molecules bind with EPS and form a soil-EPS intermediates). In particular, bacterial EPS directly acts as a cohesive force in the
formation of surface erosion resistance in soil and their sediments (Droppo
2009). For example, cyanobacteria are previously used and applied for promoting
this kind of soil adhesion studies in arid regions (Prasanna et al. 2008). Soil
modification using these EPS-rich natural products gives pathway to understand
the concept of bio-geo-civil engineering (Ivanov and Chu 2008).
7 Recent Trends in Application of Bacterial Polymers to Mitigate Organic and. . .
145