Abstract:
A large amount of mother liquor was produced during the production of glyphosate by glycine method. The mother liquor was a hazardous waste in the National Hazardous Waste List. The composition of mother liquor was complex. The content of refractory organic matter, salt, glyphosate, COD and total phosphorus in the mother liquor was high, which had great potential harm to the ecological environment and human body. The mother liquor could be better treated by membrane treatment/high-temperature catalytic oxidation or multi-effect evaporation/directional conversion. Most of the pollutants in the mother liquor could be removed by these two processes. However, in the process of treatment, not only waste gas and waste water would be discharged to the environment, but also waste salts such as disodium hydrogen phosphate, sodium pyrophosphate and sodium chloride would also be produced. The hazardous waste properties of waste salts produced by mother liquor treatment were unknown, which made their management disordered. The environmental risks of comprehensive utilization and disposal of waste salts were high. The comprehensive utilization of waste salts from glycine glyphosate process was hindered by the lack of their pollution control standards. The environmental risk of wastewater could not be effectively controlled due to the lack of pollutant discharge standards for wastewater from mother liquor treatment. In view of the current situation of mother liquor production and treatment as well as the existing problems in treatment, it was suggested to comprehensively improve the environmental risk prevention and control level of mother liquor from five aspects, namely, reduction of mother liquor, utilization of combined mother liquor treatment process, addition of waste salt from mother liquor treatment in the National Hazardous Waste List, formulation of pollution control standard for waste salts from glycine glyphosate process and water pollutant discharge standard for pesticide industry.