Currently, the treatment of sewage water, whether it comes from industrial or residential sources, has become a progressively important procedure. Rapid industrialization and modern urbanization are the key factors of numerous harmful compounds released into natural water sources, which lead to the severe contamination of freshwater supplies. Because of its increasing importance and widespread influence, environmentalists from all over the globe have been focussing more on this issue as of late. Many methods have been suggested for improving wastewater management; however, most of these have drawbacks including low mineralization, high operational costs, insufficient capacity, and the generation of waste byproducts. In this context, aerobic treatment is a feasible option for cleaning concentrated industrial effluent, as it offers a quicker alternative to the more time-consuming anaerobic treatment methods. The use of aerobic wastewater treatment as a cost-effective approach with minimal operational and maintenance expenses is becoming more common. To handle increasing wastewater loadings, it is necessary to increase biomass and dissolved oxygen levels. This chapter has evaluated the potential of pure oxygen aeration and its constraints. By using pure oxygen, it can efficiently handle larger amounts of municipal sewage while maintaining the quality of the discharged effluent. Even at lower flow rates, aeration using pure oxygen can produce a better decontamination result than mixed air.