Agitated Thin Film Dryer (ATFD) | Final-Stage Drying for Concentrated Slurries, High TDS Effluent & ZLD Systems When concentrated slurry, viscous residue or high TDS effluent needs to be converted into dry solids, normal drying methods often struggle. An Agitated Thin Film Dryer spreads the feed into a thin, continuously renewed film on a heated surface. The result is controlled final drying, better heat transfer and reliable handling of difficult feeds that are sticky, viscous, scaling or high in solids.