Effect of process control on optimization of pulp and paper mill wastewater treatment by electrocoagulation

The objective of this study was to determine the effect of electrical conductivity, pH and temperature which were kept constant during treatment via an advanced control strategy on chemical oxygen demand, color, turbidity and total suspended solids removal and energy consumption. Central Composite Design matrices were formed for aluminum and iron electrode systems separately with different combinations of 5 independent variables (electrical conductivity, pH, temperature, current intensity and electrolysis time). Obtained results revealed that aluminum electrode system was found to be more effective than iron electrode system under controlled conditions. Comparison of uncontrolled and controlled studies at optimum values of aluminum electrode system showed an increase by 31.67% in chemical oxygen demand removal and a decrease by 48.30% in energy consumption under controlled case. Results indicated that constant electrical conductivity, pH and temperature during electrocoagulation process of pulp and paper mill wastewater by means of a controller enhanced treatment efficiency. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.