Design and construction of water quality purification engineering, seawater desalination engineering, softened water engineering, circulating water engineering, water supply and drainage engineering, municipal public engineering, landscaping engineering, landscape engineering, environmental treatment engineering, water pollution control engineering, environmental protection engineering, water quality pollution prevention and control engineering, laboratory wastewater treatment engineering, air pollution prevention and control engineering, solid waste treatment engineering, physical pollution prevention and control engineering, and pollution restoration engineering; Sales of water purification equipment, drinking water equipment, softened water equipment, water supply equipment, laboratory water equipment, and medical water equipment; Research and development, sales, installation, maintenance, and repair of water treatment equipment; Sales, installation and maintenance of desulfurization equipment, denitrification equipment, electromechanical equipment, mechanical equipment, household appliances, air purification equipment, central air conditioning equipment, electronic products, and boilers; Sales, installation and maintenance of garbage treatment equipment, metal materials, hardware and electrical equipment, and chemical products (excluding flammable, explosive, and toxic hazardous chemicals); Manufacturing of specialized machinery and equipment for water resources and environmental protection