Use of Ozone-Photocatalytic Oxidation ( O3 /UV/ TiO2 ) and Biological Remediation for Treatment of Produced Water from Petroleum Refineries

Batch ozone-photocatalytic oxidation ( O3 /UV/ TiO2 ) and biological remediation by macroalgae were performed in a laboratory-scale reactor to evaluate the efficiency of these processes in the degradation of contaminants and/or decrease in the ecotoxicity of produced waters of petroleum refineries. The effectiveness of the hybrid advanced oxidation process followed by biological treatment was evaluated through the physicochemical time-course analysis and ecotoxicological tests. The results showed that after 5 min of treatment the O3 /UV/ TiO2 combination was very effective and phenol concentration decreased by 99.9%, sulfide by 53.0%, COD by 37.7%, O&G by 5.2%, and ammonia by 1.9%. The following reductions in contaminants were obtained after 60 min of oxidation treatment: phenols 99.9%, O&G 98.2%, sulfide 97.2%, COD 89.2%, and ammonia 15%. The acute toxicity tests with the bacterium Vibrio fischeri (Lumistox) and the fish Poecilia vivipara showed a high toxicity of the raw effluents ( E (L) C50