A high percentage of the solid residues in the pulp and paper industry is paper sludge produced during wood pulping and papermaking operations. The US pulp and paper industry generates approximately 100 lb of paper sludge per ton of paper produced (NCASI Technical Bulletin, 1991). Fig. 1 is a schematic illustration of paper sludge production. The disposal cost of paper sludge is approximately half of the cost of wastewater treatment (Springer, 1986); hence, the paper manufacturing industry is very interested in reducing the paper sludge disposal cost through recycling and reuse.