Abstarct: In this research, the performance and efficiency of wastewater aeration of beverage industries with micro-nano bubbles has been investigated, emphasizing the removal of chemical oxygen demand (COD). Air micro-nano bubbles were injected into a 3 cubic meter tank filled with raw sewage. Two methods of attached growth and suspended growth were used to measure their performance in COD reduction. This research showed that micro-nano bubbles have a significant effect on COD removal and ensured that it can be a suitable method in biological treatment processes, especially in the beverage industry. Also, active bio-curtains were used in the attached growth process. In both the attached growth and suspended growth processes, the reduction results were relatively similar, and in the best case, we saw a reduction of 73.75 and 75.44%, respectively. Since in this research, the raw wastewater from the factory outlet was used, and in the attach growth experiments, there were accidentally stronger wastewaters with a higher COD value, according to the equal time of wastewater processing, the actual results were obtained 1450 and 2950 mg/L reduction, respectively. The results of this research show the better performance of micro-nano bubbles with 2-day retention time compared to the existing anaerobic facilities in the Nissan-Shargh factory with 3 days; Also, the performance was better than the conventional aerators and the energy consumption was lower. The order of reaction calculated as the second order, compared to other biological methods which are the first order, and this indicates the higher speed of the reaction in aeration with micro-nano bubbles. In the end, it can be stated that micro-nano bubble is a suitable aeration method for soft drink industries.