Based on the results of our micro-pilot study, sodium persulphate could be produced efficiently and economically by conventional electrochemical means. The primary feedstock could be either sodium sulphate or sodium sesquisulphate. Our laboratory investigations had also shown that sodium persulphate was effective in supplementing conventional ClO2 bleaching of kraft wood pulp. In such an application, transitional shortage of ClO2 could be bridged economically. This finding was confirmed in a mill trial.