Environmental Engineering Reference
In-Depth Information
the strength of
κ
-CN will be improved in the near future and more applications of
κ
-CN entrapped cells including bioaugmentation will then take place.
7.3.1.3 Polyvinyl Alcohol Entrapped Cell Bioaugmentation
Up to date, there has been no work on PVA entrapped cell bioaugmentation for
wastewater treatment. Based on several previous successful cases of PVA entrapped
cell applications as a stand alone wastewater treatment process, PVA entrapped cell
bioaugmentation will likely be attempted soon. The PVA entrapped cells success-
fully removed more than 90% of contaminants such as organic carbon, nitrogen,
2-methylnaphthalene, and phenol [21, 28, 71-73]. Sharanagouda and Karegoudar
[72] reported that 2-methylnaphthalene removal efficiencies by PVA entrapped cells
(60 to > 90%) are higher than those by corresponding free cells (20-60%).
The PVA matrices provide a proper microstructure for the contaminant-
degrading cultures [57]. Figure 7.10 presents the SEM images of PPVA entrapped
atrazine degraders, which reveals two porous bead layers. The outer layer has less
porosity providing an effective structure for cell retention. Additionally, PVA matri-
ces were proven to be a good entrapment material in terms of mechanical, chemical,
and biological stabilities. The matrices were found unbroken after 6-month uti-
lization [28], reusable more than 30 times without losing degradation ability for
Fig. 7.10
SEM images of PPVA entrapped cells: (
a
) Cross-section at 250
×
,(
b
) Exterior layer at
3000
×
,(
c
) Interior layer at 3000
×
,and(
d
) External surface at 5000
×
[57]
