Interest of electrodialysis to reduce potassium level in vinasses. Preliminary experiments

Nowadays, treatment of vinasse from the alcohol fermentation is a major cost centre which decides the economic viability of this traditional industry. Increasingly stringent environment norms in France have put enormous pressure on manufacturers of alcohol from traditional feedstock like beet molasses. Nowadays, the most industrial treatment is the vinasse valorisation as fertiliser in the field after concentration. Nevertheless, the final solids are limited because of the sulphate potassium crystallisation and precipitation in evaporator tubes, storage tanks and fertiliser sprayers. The paper gives some figures of beet molasses vinasse composition, details the most widely used treatment schemes and presents the first results obtained with an electrodialysis treatment to reduce the potassium concentration in view to prevent the crystallisation and even increase the final dissolved solids of the concentrated vinasse.