This research was developed for the degradation of phenolic compounds, specifically for phenol (C6H5OH) and 2,4-Dichlorophenol (2,4-DCP) as one of the most toxic phenolic compounds and widely used as a basis for pesticides or herbicides and the like in the agricultural world. These phenolic compounds have a huge risk and potential danger to the environment and human health. Therefore, the processing of industrial wastewater contaminated with phenolic compounds is very important for environmental protection. In this study, the ozonation technique was focused on accelerating the decomposition process through the formation of hydroxyl radicals (•OH) by increasing the initial pH of the solution (pH 12), which maximized the degradation of phenolic wastewater. Ferolite, an iron-oxide-based compound (FeO/Fe2O3), which is impregnated into active sand, is used as a catalyst mainly due to its good adsorption ability, good catalytic effectiveness, and high availability. This experimental study was carried out for 60 minutes in a semi-continuous multi-injection bubble column reactor. Optimization of the degradation process in this case is obtained by observing various variable effects such as wastewater flow rate and air flow rate for ozonation, as well as the amount of catalyst for catalytic ozonation. The optimum conditions for the treatment process obtained by non-catalytic ozonation process in multi-injection bubble column reactors can be effectively used for phenolic wastewater treatment reaching 99.48% for phenol degradation and 99.83% for 2,4-DCP degradation.