Techno-economic analysis of resource recovery of glyphosate liquor by membrane technology

• A zero discharge process was proposed to recover acid, base and glyphosate.
• A cost assessment of the recovery of glyphosate is presented.
• Membrane technology is environmentally friendly to treat the glyphosate liquor.

Glyphosate is a contaminant in organisms including humans, but also in food, fodder and ecosystems. The direct discharge of mother liquor as a waste stream can cause the loss of the target product as well as a severe water pollution, which should be controlled. This study presents two alternative technologies, i.e., pressure driven membrane and electrodriven membrane, to recover glyphosate from waste liquor for resource recovery and pollution control. A cost assessment is presented. Integrated systems using nanofiltration/reverse osmosis (RO) combinations could be effectively applied in glyphosate recovery from mother liquor produced by the iminodiacetic acid process. NF and electrodialysis with bipolar membranes (BMED) are feasible and environmentally friendly technologies, and cost effective choices to treat the glyphosate liquor of the glycine dimethylphosphite (DMP) process compared to conventional technology. However, both NF and BMED are not industrially applied for glyphosate liquor treatment. For NF, the presence of phosphate in the mother liquor is a huge challenge to the membrane filtration because phosphite could lead to severe membrane scaling, which substantially reduce the membrane efficiency and membrane lifetime. The membrane price, especially for bipolar membranes, was found to be the bottleneck for BMED to be applied in large-scale applications.

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