C. Ozonation
Ozone (O3) is a powerful oxidant and has been widely used
in various industries at different stages to remove the
organic and inorganic pollutants in the wastewater. It is one
of the best treatment processes since there is no sludge
generation and it is effective for both color removal and
organic reduction through a single step (Preethi et al.2009).
Kurniawan et al. 2006, studied ozonation in combination
with Granular Activated Carbon for degradation of
recalcitrant organics in wastewater and stated that the
combination of Ozone–GAC adsorption shows the higher
removal efficiency for COD when compared to ozonation
alone. On the other hand, O3 treatment provided better
performances that UV irradiation or hydrogen peroxide
addition. In the meantime, it was observed that the
combination of ozonation with photo catalysis (UVA/
TiO2) shows better DOC removal up to 52%, although the
highest overall efficiency was obtained by the combined
UVA/TiO2/O3 with coagulation pretreatment. Westerhoff et
al. (2009) also experimented the O3/H2O2 treatment and
achieved a 75% removal of DOC contained in RO
concentrate. The combination of ozone and Biological
Activated Carbon shows a good potential in reducing
fouling problems in RO plant.