Abstract:
A method of concentrating waste liquid from a plate-making process for a photosensitive planographic printing plate precursor, including: subjecting, in a single development processing bath of an automatic developing machine, a photosensitive planographic printing plate precursor, having a radical polymerizable image recording layer on a support, after exposure simultaneously to a development process and a desensitization process using a developer liquid that contains from 1 to 10% by mass of a surfactant having a phenyl or naphthyl group and an ethylene oxide or propylene oxide group, and has a content of an organic solvent having a boiling point of from 100° C. to 300° C. of 2% by mass or less; evaporatively concentrating plate-making process waste liquid produced by the processes using a waste liquid concentrating apparatus so as to have a volume of from 1/2 to 1/10; and producing reclaimed water by condensing water vapor separated in the evaporative concentration.