Electrochemical removal of sodium ion from fermented food composts

Abstract

Fermented food composts, to be recycled into fertilizer and animal feed, require sodium chloride concentrations to be less than 1 wt% due to several toxicities. Electrochemical methods are used to remove sodium ions from fermented food composts. By washing the compost with tap water (with no electric current applied), 48% of the initial sodium ion is removed. With an electric current density of 3 mA/cm2 (the distance between the electrodes is 16 cm), the removal efficiency increases to 96% for a 36 h operation. Major factors influencing the efficiency are the treatment time and the electric current density. Removal efficiency increases with energy demand to yield 96% removal at 60 Kwh/m3. Due to the difference in relative ionic mobility, less than 9% of calcium is removed, during the same operation time, which supports the feasibility of this method.