Wastewater quality. The quality of domestic sewage is usually relatively stable, and general treatment methods include acidification, aerobic biological treatment, disinfection, etc. The reasonable selection of process flow for industrial wastewater should be based on specific water quality conditions. It should be noted that when using aerobic biological treatment technology to treat wastewater, attention should be paid to the biodegradability of the wastewater. Anaerobic biological hydrolysis acidification can also be carried out to improve the biodegradability of wastewater, or non biological physical or chemical methods can be considered for treatment.

Deepening Resource Utilization: Transitioning from "wastewater treatment" to "resource recovery", equipment will not only purify wastewater but also prioritize the recovery of resources such as nitrogen and phosphorus. For instance, struvite crystallization equipment is employed to recover phosphorus from wastewater, which is then used to produce slow-release fertilizers. The treated reclaimed water is extensively utilized in industrial production, agricultural irrigation, and urban ecological replenishment, alleviating water resource pressure.

Printing and dyeing wastewater is discharged by printing and dyeing factories that primarily process cotton, linen, chemical fibers, and their blended products. The volume of printing and dyeing wastewater is substantial, with 100 to 200 tons of water consumed for every ton of textile processed, of which 80 to 90% becomes wastewater. Characteristics of printing and dyeing wastewater: Printing and dyeing wastewater is one of the more difficult industrial wastewaters to treat, characterized by high COD concentration, high chromaticity, high salt content, refractory organic matter that is difficult to biodegrade, and significant variations in water quality and quantity over time (wastewater is discharged intermittently). The prominent issues in printing and dyeing wastewater treatment are chromaticity and refractory organic matter ....

During the pulping process, fiber separation occurs. During bleaching and papermaking, processes such as dilution, pressing, and drying of the pulp material result in the discharge of highly concentrated wastewater, known as black water, containing a large amount of pollutants such as fibers, inorganic salts, and pigments. The washing and bleaching processes generate a significant amount of intermediate water containing high concentrations of lignin, cellulose, resinates, and other components that are difficult to biodegrade. The papermaking machine discharges wastewater containing a large amount of fibers, fillers, and sizing agents, known as white water. The characteristics of papermaking wastewater include high COD and suspended solids (SS) content, and severe coloration. The SS in papermaking wastewater