Where M is the molecule weight of oxygen (32), F Faradays constant (9.64870x10 Coloumbs\ Faraday), b=4 indicates the number of electrons exchanged per mole of oxygen, van is the volume of liquid in the anode compartment (250 ml) and COD (COD in =250, COD out =20 mg \ litre) ia the change in the COD overtime "t''