Regardless of many sources of wastewater stream, a ZLD system usually consisted of two steps as shown in figure.Pre-Concentration: Pre-concentration of brine generally obtained with membrane brine concentrators. These technologies are able to recover 60-80% of the water as per following processes shown in figure 3. Evaporation/ Crystallisation: The next step, evaporation evaporates all the leftover water, collect it and direct it for reuse. The remaining waste then moves towards a crystallizer which boils all the water until all the impurities crystallise and filtered out as a solid as shown in the figure