The pollutants in hydrazine hydrate production wastewater are expressed in the form of COD, ammonia nitrogen and salinity. Therefore, the current treatment methods of hydrazine hydrate production wastewater are mainly aimed at these three kinds of pollutants. In addition, hydrazine hydrate is a specific project in the surface water source of centralized domestic and drinking water, so the degradation and removal of hydrazine hydrate in wastewater is also very important. Due to local differences, the treatment requirements and discharge standards of hydrazine hydrate production wastewater from different enterprises are also different: if the municipal pipe network in the industrial zone or non industrial zone is perfect, it only needs to be treated to meet the takeover standard of the local urban sewage plant; If there is no municipal pipe network in the industrial or non industrial area and the effluent needs to be directly discharged, it needs to be treated to meet the direct discharge standard.

1. Removal of COD

Due to the high salinity of hydrazine hydrate production wastewater, it is usually not suitable to directly adopt biochemical treatment methods, and its cod is mainly removed by physicochemical methods (such as oxidation).

2. Removal of ammonia nitrogen

The content of ammonia nitrogen in hydrazine production wastewater is usually very high, which belongs to high ammonia nitrogen wastewater. Ammonia nitrogen wastewater treatment technologies such as air stripping method, photocatalytic oxidation method, ion exchange method, chemical precipitation (map) method, membrane filtration method, adsorption method and biological method are usually used to remove it.

3. Removal of hydrazine hydrate

At present, the methods of removing hydrazine hydrate from wastewater mainly include ultrasonic decomposition, oxidative degradation and biodegradation. As hydrazine hydrate is a reducing substance, it can be converted into ammonia nitrogen by some oxidants (such as hydrogen peroxide and ozone) oxidation or catalytic oxidation (such as ultraviolet catalytic advanced oxidation) for further treatment.

4. Recovery of salt

In the production process of hydrazine hydrate, when sodium hypochlorite is used as oxidant, a high concentration of by-product sodium chloride will be produced, and when urea production process is used, sodium carbonate will be produced. These high salt wastewater need salt recovery treatment. At present, the conventional salt recovery methods are mainly physicochemical methods, such as thermal separation, membrane separation, electrochemical method and so on. Sodium chloride is mainly recovered by evaporation or distillation crystallization and salt residue purification. The recovered sodium chloride can be used as raw material for chlor alkali production, which can not only reduce environmental pollution, but also greatly reduce the production cost of chlor alkali.