Microbe-Mediated Degradation of Synthetic Dyes in Wastewater - Microbial Degradation of Synthetic Dyes in Wastewaters - page 205

Table 1 (continued)
Sl.
No.

Process Advantages Disadvantages References

even with high
suspended solid
concentration. Sim-
ple equipment and
easy implementa-
tion. Reduction of
COD (except with
reactive dyes)
possible

generation. Com-
paratively longer
reaction time
required

4. Photocatalysis No sludge produc-

tion, considerable
reduction of COD,
potential of solar
light utilization

Light penetration
limitation, fouling
of catalysts, and
problem of ne
catalyst separation
from the treated
liquid (slurry
reactors)

Konstantinous and
Albanis ( 2004 )

5. Electrochemical Effective decolor-

ization of soluble/
insoluble dyes;
reduction of COD
possible. Not
affected by pres-
ence of salt in
wastewater

Sludge production
and secondary pol-
lution (from chlori-
nated organics,
heavy metals) are
associated with
electrocoagulation
and indirect oxida-
tion, respectively.
Direct anodic oxi-
dation requires fur-
ther development
for industrial
acceptance. High
cost of electricity is
an impediment.
Efciency depends
on dye nature

Chen ( 2004 ), Rob-
inson et al. ( 2001 )

2.1 Biological Color Removal by Aerobic Microorganisms

2.1.1 Bacteria

Aromatic compounds are susceptible to biological degradation under both aerobic
and anaerobic conditions (Field et al. 1995 ). Under aerobic conditions, the enzymes
mono and dioxygenase catalyze the incorporation of oxygen into the aromatic ring
of organic compounds prior to ring

ssion (Madigan et al. 2003 ). In most mono
oxygenases, the direct coupling to O 2 is through a avin which gets reduced by the