Electrodialysis treatment of rhamnolipids hydrolysate and its waste water for use as water-soluble fertilizer

Rhamnolipids can serve as a precursor for rhamnose production, but using ion exchange resin in purifying rhamnolipids hydrolysate results in excessive high-salinity wastewater, making the process environmentally and economically unfeasible. This study introduced electrodialysis technology as an alternative for purifying rhamnolipids hydrolysate, significantly reducing wastewater to less than 5 % compared to the resin method. To achieve zero wastewater discharge, the electrodialysis-treated wastewater was repurposed into a water-soluble fertilizer containing 7.1 g/L of rhamnolipids, 11.4 g/L of fatty acid, 2.4 g/L of amino acid, and 8.2 g/L of po-tassium. Unlike traditional fertilizers, the nutritional components with rhamnolipids showed remarkable po-tential in enhancing tomato plant growth, flowering, and fruit quality. Taken together, the electrodialysis treatment of rhamnolipids hydrolysate largely reduced the water volume, the economic cost, and took a full use of the final wastewater as efficient water-soluble fertilizers, making it applicable for large-scale rhamnose production.

Automated summary

This study introduced electrodialysis technology as an alternative method for purifying rhamnolipids hydrolysate, significantly reducing wastewater generation and repurposing it into water-soluble fertilizer. This fertilizer with various nutritional components showed promising effects in enhancing tomato plant growth and fruit quality. The electrodialysis treatment has the potential for reducing water volume and economic costs, making it suitable for large-scale rhamnose production.