In special separation projects, water treatment membrane technology is mainly used for material concentration, dye wastewater treatment, and protein separation in biopharmaceuticals. Nanofiltration membrane and electrodialysis technologies play a role in selective separation in these fields, such as nanofiltration for the separation of substances with molecular weight differences and electrodialysis to deal with acid and alkali recovery. Downstream purification in biopharmaceuticals requires ultrafiltration and microfiltration to remove viruses or cellular debris to ensure product purity and safety.