The feasibility of the use of an electrocoagulation system (EC) directly powered by a photovoltaic (PV) array has been demonstrated. The model pollutant used was a reactive textile dye Remazol Red RB 133. It has been proved that PV array configuration is a factor of great influence on the use of the generated power. The optimum PV array configuration must be reshaped depending on the instantaneous solar irradiation. A useful and effective methodology to adjust the EC-PV system operation conditions depending on solar irradiation has been proposed. The current flow ratio, J(v), is established as the control parameter. (C) 2007 Elsevier B.V. All rights reserved.