Zero Liquid Discharge (ZLD) technology is to pretreat and evaporate industrial wastewater, collect the condensed water distilled from the zero liquid discharge system for water recycling applications, and send unevaporated solids to landfills or use them as valuable salt. Class by-products are reused. In 2018, the global ZLD market demand was approximately 5,442 million U.S. dollars, with the largest industrial application being the energy and power industries, followed by the petrochemical and chemical industries.

In recent years, the world has been affected by extreme climates, and the supply of water services has begun to face major changes and tests, causing the world to face more serious water shortage problems. The fierce competition for water resources comes from the fact that the earth will face a 40% water shortage from 2030.