Diester plants produce large quantities of glycerin solutions, whose commercial exploitation requires sodium sulphate elimination. Bipolar electrodialysis (BED) has been investigated for its capability to both demineralize solutions and to produce alkali and acid solutions. Demineralization rates above 80% were achieved with glycerin loss below 2%. Alkali and acid solutions were obtained with a final concentration of about 2 N and an energy cost of about 0.5 kWh/kg of pure glycerin. The treatment of waste solutions could be realized with a membrane area of 100 m(2). Economic evaluation demonstrates the suitability of BED since demineralization allows the upgraded solution to be sold at a price 1.4 times higher than the initial solution.