CE= M0∫tIdt/(Fb ʋan ∆COD)                                                                     

Where M is the molecular weight of oxygen (32), F is Faraday’s constant (9.64870x104 Coloumbs/faraday), b=4 indicates the number of electrons exchanged per mole of oxygen, ʋan is the volume of liquid in the anode compartment (250 ml) and ∆COD (CODin= 250, CODout= 20 mg/litre)is the change in the COD over time, ‘t’.