11 Water purification installations, namely, water purification units; water purifying apparatus and machines, namely, water filtering units for domestic, commercial or industrial use, iron removal units, disacidification units, demanganization units, precipitation units, water hardening units, water disinfection and distillation units, desalination units, water softening units, degassing units; filtering units for chemical liquids, conditioning and purifying units using ion exchangers for water and chemical liquids; parts of complete structures for river water intake by means of siphon pipes or pumps, namely, coarse screens, fine screens, drum-sieves and pumps; parts of complete river waterworks, namely, coarse screens, fine screens, sieves, pumps, sedimentation tanks, rapid filters; parts of complete chemical dosing stations consisting of dissolving tanks and sedimentation tanks, dosing units and storage tanks, discharging and transportation units for chemicals; sedimentation units for process water; waste water purification units and plants for domestic, commercial and industrial waste water, waste water purification units comprising biological aerated filters and membrane filters; bioreactors used in purifying industrial waste water; process water treatment plants for treatment of fresh and recycled water; potable water treatment plants using multi-barrier systems for treating surface and ground water; sea and brackish water desalination plants; evaporators and evaporation plants; driers for industrial use, fluidized bed driers, sludge drying units, sludge treatment plants