Abstract: The present invention comprises an additive for compound feed for pigs, sheep, goats, poultry, cattle, horses, dogs, cats and fur-bearing animals, which contains an organic or inorganic acid, or salts thereof, espacially formic acid, with a beneficial effect on the treatment of compound feed, and a spent sulphite liquor from an acidic or neutral cellulose sulphite cook. The additive contains the acid or salts thereof in an amount ranging from 10-90 percentage weight, and the spent sulphite liquor in an amount ranging from 10-90 percentage weight. The additive is added is added to the compound feed in an amount ranging from 0,2 to 3,0 %. The spent sulphite liquor can be adsorbed on a suitable carrier, such as soy meal or water-adsorbing silicates, in order to attain a dry composition.

Abstract: A process for the production of vanillin, 3-methoxy-4-hydroxy-benzaldehyde comprising ultrafiltrating a waste sulfite liquor to obtain a concentrated lignin-rich fraction, and oxidizing said fraction by convention procedures. Advantages of the process are increased yields of vanillin and reduction or avoidance of scale formation on production equipment.