Introduction: During developing, because the alkaline developer reacts with the photosensitive layer of CTP exposure, the solution turns from colorless transparent state to green, dark green, or even a darker color. With the increase of developing times, the developing effect becomes poorer gradually, which greatly influences the printing plate developing quality. In order to keep a consistent developing effect, it is required either to remove old solution regularly and quantitatively and add new developer or replace the developer. Both removed old solution and replaced developer are developer waste-water, which will pollute the environment seriously if it is directly drained into the sewer. Thus, the printing plate developer waste-water should be treated before drainage.

UF membrane can purify, separate, or concentrate solution. Separation technology can remove 0.01~0.001 μm substances and intercept tiny suspensions and colloids, so as to realize the purification, separation, and concentration of raw solution. The application of UF membrane technology to treatment of printing plate developer waste-water can not only make the waste-water reach the discharge standard but also recycle the waste-water, optimizing the waste-water and sewage resources.

Technological process: Developer waste-water flows into adjustment tank for adjustment of water volume and quality from storage tank, so as to ensure its stability. Waste solution is delivered by centrifugal pump through precision filter to UF membrane module. After separated by the membrane, developer waste-water becomes clear and transparent. The UF membrane module can recycle developer waste-water to fulfill zero emission and to cut the recovery cost.