Ozonation was carried out for decolorization and COD removal of raw and anaerobically treated UASB
(upflow anaerobic sludge blanket) combined industrial (mainly textile) effluent in a lab-scale bubble column
reactor. Ozonation of anaerobic bioprocess effluent at a dose of 300 mg/h for 10 min resulted in
81% color and 75% COD removal (100 mgO3
/80 mg COD) while for raw wastewater 25 min ozonation
furnished 51% color and 67% COD removal (250 mgO3
/345 mg COD). Optimal process conditions for
biotreated effluent (pH = 8 and temperature = 25°C) resulted in 100% color and 96% COD removal for 10
min ozonation (100 mgO3
/104 mg COD). Electrical energy comparison demonstrated that post ozonation
required less electrical energy, 16 and 2.9 times as compared to pre ozonation.