ZLD (zero liquid discharge) is a wastewater distillation process that helps reduce waste brine discharge to the environment and recover the majority of the wastewater as clear reusable water. In addition, it can turn the brine to a solid waste and in some cases even a useful product that can be profitably sold.
The ZLD process is becoming very important and economical for many industry segments to meet more stringent environmental regulations. Industries such as power, chemical, refining, manufacturing, paper, and others utilize ZLD processes. One of the last steps of the ZLD process is crystallization, in which the concentration is further increased by evaporating water from the pre-filtered or already concentrated wastewater to a level not possible or efficient by distillation.