Conclusions
Ozonation showed best results for post treatment of anaerobically
treated effluent for color and COD removal as compared to the pretreatment of combined industrial wastewater
of the same nature. However, efficiency of the ozonation
process was further increased at elevated pH. Optimal
results for raw and biotreated wastewaters were observed at
pH 9 and 8, respectively. Temperature showed an adverse
effect on the removal efficiency as an increase in temperature
(> 30°C) resulted in continuous decrease of color and
COD degradation. Electrical energy comparison demonstrates
that post ozonation is a more cost-effective and feasible
option.