Methods are provided for reuse of a sludge from a waste fiber supply including an organic fraction and an inorganic fraction. Generally, methods include converting the sludge by burning the sludge to remove a majority of the organic fraction and produce an ash with inorganic materials in an amount of at least about 80% by weight of the ash and adding the ash to a plastic pyrolysis system in an effective amount to remove at least a portion of one or more contaminants from a plastic feed stream of the plastic pyrolysis system. Integrated recycling systems also are provided and include a fiber recovery system; a means for at least partially dewatering a sludge; a burner; and a pyrolyzer.