Abstract: Disclosed is a method for coagulating the suspended solids in paper mill waste water so that the coagulated solids may be easily separated from the waste water and the clarified waste water reused in the paper making process. Coagulation is induced by first adding sulfuric acid to lower the pH to below 4, mixing thoroughly, and then adding calcium hydroxide to raise the pH to above 10. The coagulated solids separated from the waste water may be used as a landfill, used as a low grade pulp source, or dewatered and burned as a fuel.

Abstract: A selectively operable interposer mechanism for positioning bars, or the like, in a card selector or coder. Each interposer includes an interposer blade of magnetically responsive material disposed in a longitudinal slot of a nonmagnetic platen. A bar is disposed in each slot and is adapted to be pushed by the interposer blade acting through a rolling disc disposed in the slot between the blade and bar. Disposed directly above each interposer blade is a solenoid coil effective, when engaged, to pivot the associated interposer blade into contact with a permanent magnet which captures the interposer blade. A pusher assembly including the permanent magnet is operative to displace each captured interposer blade and the associated bar longitudinally along their respective slots from a rest position to a displaced position. After a coding or sorting operation, the pusher assembly returns the bars and interposers to their initial rest position.