3.3. Electric energy consumption
The important economical parameters in PEP are including: electrical energy consumption and current efficiency that the major operating cost of electrochemical process is associated with them. As shown from Fig. 9, the minimum energy consumption, was 2 kWh (kg COD)−1 at 20 mA cm−2 current density for 60 min electrolysis time that was calculated using the Eq. (23):