Wastewater characteristics Biodegradability parameter Work highlights Reference
Municipal WWTP effluent BOD5 Biodegradability increase due to the change in molecular structure of refractory compounds decreased inhibitory effects [68]
Textile dye BOD5 increase, BOD/COD, OD/TOC Under optimal conditions, the BOD/TOC and BOD/COD ratios increased up to 0.58 and 0.27, respectively. [69]
Phenolic solution BOD5/COD The BOD5/COD ratio increased to 0.18, 0.26 for the test solutions, under the best treatment time. [70]
Pulp mill alkaline bleach plant effluent BOD5 increase COD reduction Ozone treatment enhanced the biodegradability of the effluent, monitored as 21% COD reduction and 13% BOD5 enhancement [71]
Procaine penicillin G formulation effluent BOD5 No significant correlation existed between the BOD5 and the toxicity test results [72]
Diclofenac in aqueous solution BOD5/COD Zahn-Wellens test Ozonation promotes a more biocompatible effluent of waters containing diclofenac [73]
Textile wastewater BOD5/COD Biodegradability enhancement by a factor up to 6,8-fold [74]
Table 5: Evaluation of ozone effect on wastewater biodegradability.