Valorization of Waste Fines and Reject Fibers Produced in Recycled Liner Manufacturing - Biochemical Conversion Processes

Recycled linerboard mills produce packaging paper from old corrugated carton (OCC) wastes by first repulping them, followed by refining of the pulps to improve the bonding abilities of the fibers. A large amount of fiber fragments known as fines are produced in this process. The waste streams contain significant amount of such fines in addition to calcium carbonate and clay fillers. The removal of hornified cellulosic fines can accelerate water removal from the pulps on the papermachines and in the dryer sections, leading to significant productivity increases while improved inter-fiber bonding in the sheet due to a lower ‘waste fines’ content improves strength. These waste fines and fiber rejects from the repulping process can be converted into higher value added products if successful conversion processes are developed.

We discuss the bioconversion of these waste fines by enzymatic hydrolysis into sugars which are further converted into biodegradable bioplastics such as polyhydroxy-alkanoates (PHA)s. Other routes for valorization can include methods of 're-activating' the hornified cellulosic surfaces by cationic polymers and their reintroduction into the furnish.