RECYCLING PULP AND PAPER SLUDGE IN MEDIUM DENSITY FIBERBOARD PRODUCTS

摘要

Water treatment processes in pulp and paper mills generate solid residues called pulp and paper sludge. The most common sludge disposal methods are landfilling, incineration for power production, and land application for soil amendment. Current disposal alternatives are affected by shrinking space, public opposition, increasing regulatory pressure, and above all, poor economics. Valuing sludge as a commercial product would be a beneficial way to recycle this residue. Pulp and paper sludge is valuable for medium-density fiberboard (MDF) manufacturing because primary sludge (PS) contains fibres and secondary sludge (SS) has adhesive properties. PS represents a fibre source for the growing MDF industry that faces decreasing forest resources. SS contains proteins that may react with formaldehyde (HCHO) in adhesives. It can therefore be used as additive to produce reduced urea-formaldehyde (UF) resin content MDF products and reduce toxic HCHO emission. The general objective was to evaluate the characteristics of different sludge sources available and their potential for MDF production.