Case Studies on Deinking Wastewater Treatment

Wastewater Issues: The domestic packaging industry primarily uses water-based ink printing technology. During production, the process of changing inks and cleaning printing equipment generates a certain amount of ink wastewater, which is characterized by very high color intensity and COD values. Biological treatment methods cannot be used, as the primary pollutants are water-soluble acrylic resins (color carriers), cyclic organic compounds with chromophores (pigments), and high-molecular-weight alcohol- or phenyl-based dispersants, which cause COD levels to exceed regulatory limits.

Solution: First, improve the wastewater’s biodegradability through pretreatment, acid washing and coagulation, neutralization, and filtration; then send it to a contact oxidation tank, where it is mixed with domestic wastewater for advanced treatment. Polyacrylamide products are primarily used in mixed wastewater treatment processes. In this process, polyaluminum chloride is also required as a coagulant. After treating the residual sludge and other physicochemical contaminants in the system, they are concentrated to form a sludge cake, enabling environmentally friendly recycling.

Treatment Results: Meets discharge standards