How to treat the wastewater in the flexo process?

With the increasingly stringent environmental protection requirements for volatile organic components, many flexographic printers are trying to use water-based ink technology to reduce environmental issues. With the increase in the production and use of water-based inks, many of the waste-water treatment operations for these inks also need to change. Wastewaters that use water-based inks include pigment particles (pigments and dyes), binders (alkaline soluble substances, emulsions, or colloidal dispersion chemicals), and auxiliary solvents (alcohol, glycol, and glycol ethers). And some other additives (waxes, plasticizers and defoamers). Colored wastewater may be the most important concern. The specified chemical composition and the number and quality of the particles may exceed the maximum that the environment can tolerate. In order to discharge the wastewater directly into the environment, a rot system can be selected to treat the wastewater. Industrial wastewater is not allowed to be discharged into rot systems. Because the working waste water will be discharged into the rot system, it will cause groundwater pollution problems and therefore require additional cleaning costs. For printers, discharging wastewater to a public sewer treatment plant is the smartest way. In foreign countries, discharge of waste water into a sewage channel needs to be approved by relevant agencies. Prior to obtaining permission, the composition of the emissions should be analyzed by a dedicated sewer treatment plant and then licensed according to the circumstances. The most practical methods of wastewater treatment for water-based flexo ink printing are the following: 1. Chemical separation in a continuous or batch process. After adjusting the pH of the wastewater, the solid particles were subjected to flocculation treatment and continuous wastewater treatment. 2, small filter, extreme filtration, fine filtration and anti-leakage treatment. This kind of treatment works a bit like a mammal's kidney function. 3. Use activated carbon black for bioabsorption treatment. 4. Oxidation and ozone/ultraviolet oxidation mode system oxidation techniques. 5, the quality and content of waste water, is the key to choose the processing method. For most flexo manufacturers, chemical separation is generally applicable. Although many companies can use simple methods to filter and treat wastewater, removing some solid substances and some colored particles, it is important to understand the following points: Many flexographic wastewaters and cleaning solutions will be changed due to the addition of ink, water, and cleaning solution. Emulsion formation. The method for effectively treating the waste water can first use a chemical separating agent to separate the emulsion and then physically filter the remaining substances. There are many chemicals that can be used for emulsion treatment and will be completed in the following steps: • Neutralization of pH • Use of absorbents to absorb specific chemical and suspended substances in water • Addition of additives to agglomerate solvent substances • Suitable for use Chemical solid components that are hazardous to industrial processes • Physical filtration using a band filter or filter press operation. The optimum operating environment for most chemical separation agents is between pH 6.5-9. If the pH of the wastewater exceeds this range, pre-treatment and conditioning should be performed. Water looks easy to come by and it is cheap. However, the actual use and processing costs are very high. Therefore, minimizing the amount of water used is also a cost saving and environmental protection aspect. Reducing the use of water resources will reduce the amount of waste water. Ways to reduce water consumption include: reducing raw material use and recycling. From the environmental point of view, raw material reduction will be better than recycling. How to control the amount of water? Regularly draw water consumption maps and water balance (in/out) maps in the plant, and try to find water saving methods to determine a series of water saving procedures. The following training for the printing staff can reduce the amount of water used. · Discharge the ink into the container as much as possible. • Completely wipe the printer components before cleaning with water. • Before the ink is dried, the cleaning efficiency is increased by making the ink device cleaner. Use a low-flow nozzle. Use a water saver. Using the reused wastewater, the following adjustments can be made to the cleaning of the printer: 1. Use dirty water to wash away most of the ink 2. The ink left after the first cleaning is cleaned with clean waste water. The remaining ink is rinsed with clean water