Method for classifying, treating and recycling plating washing water on line

The invention discloses a method for classifying, treating and recycling plating washing water on line, which comprises the following steps of: removing oil, coarsening, reducing, activating, peptizing, chemically plating nickel, preplating nickel, plating copper, plating nickel and plating chromium in a plating process; and treating water and washing water during production and cleaning. The method specifically comprises the following steps of: preparing pure plating water, circularly processing acid and alkaline waste water, coarsening, circularly treating chromium-plating washing water, circularly treating chemically nickel-plating washing water, circularly treating copper-plating washing water and circularly treating nickel-plating washing water. Waste water in each procedure is directly used beside a tank edge in a closed cycle by an economical and effective means after being treated, no wastewater is discharged, and the cross contamination of different water qualities among the procedures is avoided. The method is a technological innovation for realizing zero emission of plating waste water and plating cleaner production.