| 摘要 |
PROBLEM TO BE SOLVED: To obtain a pH lowering agent hardly generating scum at a time of the pH reducing treatment of alkaline industrial waste and a pH reducing treatment method, especially, the pH lowering agent of the developing treatment waste soln. of a photosensitive lithographic printing plate capable of stably and certainly lowering pH without generating the scum caused by the gelling of silicate or the precipitation of a polymer and a method for lowering the pH of a developing treatment waste soln. SOLUTION: A pH lowering agent of alkaline industrial waste with a pH of 12.5 or more containing reducing sugars and the pH lowering agent wherein the alkaline industrial waste contains a waste soln. obtained by the development treatment of a photosensitive lithographic printing plate are designated and, in a method for lowering pH of the alkaline waste soln. with a pH of 12.5 or more, the pH lowering agent is added to the waste soln. |
