Sewage treatment processes exhibit varying energy intensities, mainly dependent on the methods used. Traditional plants, with mechanical processes like aeration, pumping, and equipment operation, often demand substantial energy. However, advancements such as membrane bioreactors and innovative reactor designs are actively working towards optimising energy usage in sewage treatment. Biological treatment methods, like activated sludge processes and anaerobic digestion, can contribute to overall energy intensity, particularly during aeration. The wastewater treatment industry is proactively engaged in initiatives to enhance energy efficiency. This involves exploring the incorporation of renewable energy sources and adopting sustainable practices to strike a balance between achieving effective treatment outcomes and minimising the environmental impact, including energy consumption.