equipped with a pump 24 this conduit 23 leading to a hydrocyclone 25 extending out of the hydrocyclone 25 is a line or conduit 26 to a second secondary pulper or fiberizer 30 which can be constructed in the same manner as the first secondary pulper or fiberizer 10 thus as a matter of convenience the components or parts thereof have been designated by generally the same reference characters as the analogous parts or components of the fiberizer 10 leading from the outlet housing 15 of the second secondary pulper or fiberizer 30 is a line or conduit 31 to the good stock vat 18 an outlet line or conduit 32 which extends out of the central region of the housing 11 of the fiberizer 30 leads to an intermediate vat 33 or equivalent structure an outlet line or conduit 34 leading from the circumference of the housing 11 of the secondary pulper or fiberizer 30 conveys heavy contaminants or rejects which should be eliminated from the installation and deposited leading from the intermediate vat 33 is a line or conduit 35 which extends to a dynamic jarrer or vibrator 36 which contains a vibrating screen 37 and a throughpass container or vat 38 leading outwardly from the throughpass container 38 is an outlet or outfeed line 40 which has two branches 41 42 and specifically branch 41 which leads to the good stock vat 18 and a.