This category encompasses specialized equipment for purification and treatment of industrial water used in manufacturing facilities. It handles cutting fluid purification systems, coolant filtration systems, wastewater treatment equipment, pure water production systems, ion exchange resin equipment, reverse osmosis membrane systems, oil-water separation equipment, sedimentation tanks, activated carbon filters, and UV lamp sterilization equipment. It includes essential water quality management systems for manufacturing processes such as cutting fluid recycling in metal processing, pre-treatment water production for plating processes, water quality control in cleaning processes, and wastewater purification for environmental regulation compliance. This category is clearly distinguished from air pollution control equipment and noise control devices, positioned as environmental equipment specialized in water and liquid treatment.