TREATMENT OF WASTE LIQUID OF PHOTOSENSITIVE RESIN PLATE

PROBLEM TO BE SOLVED: To execute flocculation, separation and filtration for a short time utilizing a simple device by mixing a macromolecular cationic flocculating agent with resin containing waste liquid, at the time of treating the resin containing waste liquid generated when a photosensitive resin plate which contains an ionic hydrophilic group shown by the specified formula is developed by developer to remove an uncured resin. SOLUTION: At the time of treating resin containing waste liquid generated when a photosensitive resin plate which contains at least one ionic hydrophilic group selected from the group consisting of a group shown by -COOM, -SO3M, -SO4M, -nPO(OM), (O)3 and -nPO(OM)n (wherein M is hydrogen atom, a I-III element, amine group or ammonium group and n is 1-2) is developed by developer to remove an uncured resin, a macromolecular cationic flocculating agent is mixed with the resin containing waste liquid. The macromolecular cationic flocculating agent is a copolymer consisting of amines and epichlorohydrin. The macromolecular cationic flocculating agent is mixed with the resin containing waste liquid to flocculate the resin in the waste liquid and then an acid compound is further mixed to the resultant liquid.