The soil perfusion technique for the biological degradation of sulfite waste liquor.

Considerable attention has been given to chemical methods of reducing the Biochemical Oxygen Demand (B.O.D.) of semi-chemical neutral sulfite waste (S.N.W.). Very little study has been devoted to a biological method. The exact composition of this paper industry waste will vary with the type of wood chip used and the modification of cook. Table 1 shows a typical composition of the liquor resulting from a semi-chemical soda cook.