Zero-discharge process system for sewage treatment

The invention discloses a zero-discharge process system for a sewage treatment system. The zero-discharge process system gives consideration to sodium chloride crystal recovery and sodium sulfate crystal recovery. The whole zero-discharge system is formed by organically combining reclaimed water external supply, sodium chloride recovery and sodium sulfate recovery, each part is divided into a plurality of units like a pretreatment unit, a softening unit, a salt separation unit, a sodium chloride concentration and purification unit, a sodium sulfate concentration and purification unit and an MVR evaporation and crystallization unit according to functions, and each unit is divided into a plurality of subsystems according to different specific treatment modes. The large-scale zero-discharge system can realize the concentrated water treatment capacity of about 38800 tons/day, the recyclable water resource is about 30000 tons/day, and the total recycling amount of sodium chloride and sodiumsulfate is about 540 ton