Providing new distilling and/or de-scaling methods and systems herein is a matter of allowing for thermal balance without the need to fill a hot wet emulsion separation system with more steam and heat rejection devices to waste steam. A solutions set begins with efficiently utilizing three types of waste: (1) de-oiled and/or cooled down produced water; (2) blowdown steam from drum-type boilers (DBs); and (3) return condensate of dry steam from the DBs. It ends with: (1) removing calcium hardness, magnesium hardness and silica, thereby recovering them as useful minerals; and (2) producing distillate for viscous oil recovery by steam injection and de-scaled hot brine for improved oil recovery by hot water flooding and/or other related methods. The vehicle to attain this solutions' set is a multi-effect distillation train comprises a backward feed section along with two flashing stages.