In waste, one of the important indicators is Chemical Oxygen Demand (COD). COD is the need for oxygen to oxidize organic substances contained in one liter of water. Chemical or chemical oxygen requirements for the oxidation reaction of waste materials in water. Chemical Oxygen Demand is an important water quality parameter because it can assess the effect of effluent from wastewater to be discharged into the receiving environment (water bodies). In this study, COD analysis was carried out using optimum conditions at 700 W and an air injection flow rate of 0.2 lpm, 0.02 M concentration of Na2SO4 electrolyte, 0.5 cm tungsten anode depth, 60°C of operating temperature, 100 mg/L initial phenol waste concentration, Fe2+ ion concentration 20 mg/L, volume of sample solution 1.5 L, and stirring speed 2 mot. The results showed a decrease in COD levels which only reached 71.14% due to cyclic chains in the widest area. Observation analysis of LC MS obtained the formation of intermediate compounds which include 2-Oxo-1.3-dioxole-4.5-dicarboxylic acid, ethyleneetetracarboxylic acid, and 2.2-oxydisuccinic acid.