ANAEROBIC-DIGESTION OF WASTE-WATER PRODUCED IN THE MANUFACTURE OF CELLULOSIC PULP FROM WHEAT-STRAW IN IMMOBILIZED CELL BIOREACTORS

The kinetics of the anaerobic digestion of wastewater produced in the manufacture of cellulosic pulp from wheat straw (GOD of 38.8 g/l) were studied. Laboratory experiments were carried out in 1-1 bioreactors containing supports of different chemical composition and features, namely: saponite, montmorillonite, bentogel, sepiolite (pansil) and PVC, to which the microorganisms responsible for the process adhered. The process was simultaneously performed in a control digester with suspended biomass. The bioreactors used were batch fed by incrementing the volume loads from 10 to 200 ml over a period of 5 months. Inhibition phenomena and low biodegradability of the wastewater (29-30%) were observed in the COD range studied (0.4-7.8 g/l) due to the accumulation of lignin and its derivatives. The model used showed a slight influence of the support on the kinetics of the biodegradation.