[1][2] ZLD technologies help industrial facilities meet discharge and water reuse requirements, enabling them to meet government discharge regulations, reach higher water recovery (%), and treat and recover valuable materials from the wastewater streams such as potassium sulfate, caustic soda, sodium sulfate, lithium, and gypsum.
Thermal technologies are the conventional means to achieve ZLD, such as evaporators (for instance multi stage flash distillation), multi effect distillation, mechanical vapor compression, crystallization, and condensate recovery.
ZLD processes begin with pre-treatment and evaporation of an industrial effluent until its dissolved solids precipitate.
[3] This has led to processes like electrodialysis, forward osmosis, and membrane distillation.
A quick overview and comparison can be seen in the following representative table:[4][5] Despite the variable sources of a wastewater stream, a ZLD system is generally comprised by two steps: