In order to meet the conductivity emission standards, some factories have gradually adopted zero-discharge wastewater systems. However, the end still produces solid waste such as miscellaneous salt or sludge. If you want to improve this situation, you must adopt a zero-discharge wastewater solution with full resource recycling. Taking semiconductor factories as an example, in order to solve the problem of ammonia nitrogen wastewater, most use MD (membrane deaerator) membranes to separate ammonia nitrogen in wastewater and use sulfuric acid to absorb the ammonia sulfate waste liquid with a concentration of about 30wt%, which is outsourced and transported to reuse plants for treatment. Since the water body is too large in forepart, sulfuric acid must be added to adjust the pH to 6.5~7.0 before entering the RO system to concentrate the water body to about 20% of the original water volume; liquid caustic soda must be added to adjust the pH to 11~12 required by the MD system. Although the ammonium sulfate method solves the problem of ammonia nitrogen in wastewater, it also contributes a large amount of conductivity. For this reason, our company has issued a method without medicine, using high-pressure seawater RO, evaporation concentration system and crystallization system to directly produce industrial ammonium sulfate products. At the same time, a mechanical vapor recompression (MVR) system is used to save energy in the evaporation system, reducing energy consumption by more than 80%.