Environmental Engineering Reference
In-Depth Information
Water out
(a)
Hollow glass tubes
Reflector
Steel casing
Converging lens
TiO
2
and SiO
2
coating
Light source
Water in
TiO
2
and SiO
2
coating
(b)
Light in
Reflector
FIGURE 1.2
(a) Schematic diagram of photocatalytic reactor. (b) Schematics of one hollow tube.
1.5 Conclusion
The work conducted has shown that crumb rubber is an effective iltration medium because of
its favorable porosity gradient. The bottom layer comprising coarse rubber particles does not
promote clogging of the iltration column. The iltered water showed a small head loss (7 cm) at
high iltration rates such as 20 m/s. The turbidity was reduced to low levels (3.0 NTU), suspended
solids were not observed, and the TDS showed lower levels. Exposure of water obtained from
the iltration column showed no evidence of the presence of
E. coli
,
Shigella
spp., and
V. c h o l e r a e
.
The application of the bimodal technique of crumb rubber iltration and UV-supported
n
-TiO
2
catalysts showed a signiicant improvement in water quality. The physiochemical characteris-
tics of water matched the standards invoked by WHO. The current work on the scaling up of a
photocatalytic reactor is based on using hollow nanostructured tubes coated with mesoporous
TiO
2
and
n
-SiO
2
for uniform relection of light. It is expected that this work shall enable the
scaling up of the photocatalytic reactors and allow a new generation to treat the wastewater
from the textile, agricultural, and chemical industries, which is highly challenging.
Acknowledgments
The authors thank Faheemuddin Patel of KFUPM, Dhahran, Kingdom of Saudi Arabia, for
his help in the work done on crumb rubber iltration, and Rizwan Ahmad of COMSATS for
his contribution in designing the photocatalytic reactor. The help provided by Zahra Khan
and Tayyaba Abid is appreciated.
