4. Conclusions
In this study, the wastewater stream after the industrial reactive
dyeing process was taken into consideration. Due to high
salinity, high pH and intense color, it is the most problematic textile
wastewater type from an environmental perspective. It was
indicated that, using O3 or O3 combined with a moderate concentration
of H2O2 (below 0.005 M) results in good color reduction
and an increase in mineralization, biodegradability and a reduction
in the toxicity of hazard compound RB5. In turn, for the AOPs in
which higher concentrations of H2O2 and/or UV irradiation were
used, lower values of BOD5/COD ratio were found. Treating afterdyeing
discharge by ozone-based AOPs can be a first stage in the
textile wastewater purification process, e.g., prior to biological
treatment, or it can be the only operation when the purified
after-dyeing discharge is used as a source of concentrated brine
(ready to use). Moreover, treating the selected textile wastewater
stream, in this case, after-dyeing discharge, by using a customized
method can be economically reasonable for industry. It should be
noticed that conducting the research focused only on the oxidation