Printing plants using water-based ink do indeed require wastewater treatment. This is because water-based ink wastewater has some special properties, such as high COD (chemical oxygen demand), high chromaticity, and difficult biodegradation. If directly discharged into the environment, it will cause serious pollution to water bodies, threatening human production and life as well as the ecological balance of nature.
During the printing process using water-based ink, printing factories generate a large amount of wastewater, which contains residues, impurities, and cleaning agents used for cleaning equipment. If these wastewater are discharged directly without treatment, it will not only cause environmental pollution, but may also trigger a series of ecological problems.
To treat these wastewater, printing factories can adopt various sewage treatment methods, including chemical, biological, physical, and comprehensive methods. The specific choice of method needs to be comprehensively considered based on factors such as wastewater quality, scale, discharge standards, and treatment costs.
Chemical method: using chemical reactions to remove organic matter, nitrogen, phosphorus and other elements from wastewater. Common chemical agents include sodium chloride, calcium chloride, sodium sulfate, etc. Chemical methods have good treatment effects, but the cost of chemicals is high and may cause secondary pollution.
Biological method: using the degradation effect of microorganisms to remove organic matter, nitrogen, phosphorus and other elements from sewage. Commonly used microorganisms include aerobic bacteria, anaerobic bacteria, etc. The biological method has stable treatment effects and low operating costs, but the treatment time is relatively long. For high concentration water-based ink wastewater, anaerobic biological treatment can be used to degrade it first, improve the biodegradability of the wastewater, and then enter the aerobic biological treatment system.
Physical method: Using methods such as filtration, precipitation, and air flotation to remove suspended solids and insoluble solids from wastewater. The physical method has good processing effect and low operating cost, but the processing time is relatively long. For water-based ink wastewater containing a large amount of suspended solids, a coagulation air flotation combined process can be used for treatment.
Integrated approach: Combining chemical, biological, and physical methods to fully leverage their respective advantages and achieve optimal treatment results. The comprehensive method has stable processing effect, low operating cost, and short processing time.