The wastewater treatment process for garment factories is designed based on the source and characteristics of their wastewater. Based on the actual production processes in the garment industry, the typical mainstream treatment process adopts a combination of “pretreatment + biological treatment + advanced treatment + disinfection/sludge treatment,” with the specific steps as follows:
1. Pretreatment
1.1 Bar screen interception: Removes large solids (fabric, thread ends, buttons, etc.)
1.2 Equalization tank: Homogenizes and equalizes volume, adjusts pH to 6–9, and stabilizes water quality.
2. Main treatment
2.1 Coagulation and sedimentation: Adds PAC (polyaluminum chloride) and PAM (polyacrylamide) to remove suspended solids, colloids, and some color.
2.2 Biological treatment:
2.2.1 Anaerobic treatment (e.g., UASB, hydrolysis acidification): Improves biodegradability and decomposes large molecular organic matter.
2.2.2 Aerobic treatment (e.g., activated sludge process, biological contact oxidation): Degrades organic matter and ammonia nitrogen.
3. Advanced treatment (depending on reuse or discharge standards)
3.1 Filtration: Sand filtration and activated carbon adsorption remove residual organic matter and color.
3.2 Membrane technology: Ultrafiltration (UF), nanofiltration (NF), or reverse osmosis (RO) for high reuse rate scenarios.
3.3 Advanced oxidation: Such as Fenton oxidation and ozone oxidation, used for decolorizing recalcitrant dyeing and printing wastewater.
4. Disinfection
4.1 Using ultraviolet light, ozone, or sodium hypochlorite to kill pathogenic microorganisms, especially suitable for wastewater containing medical textile washing wastewater.
5. Sludge treatment
5.1 Sludge is concentrated and dewatered (e.g., by belt filter press or screw press) before being transported for disposal; some is dried and then utilized as a resource.
