Ex situ pilot scale electrokinetic restoration of saline soil using pulsed current

This study was conducted to investigate electrokinetic removal of salts from saline soil with reduced electrical energy consumption using pulsed current that periodically repeats on/off using a direct current (DC) power supply in a pilot scale system (15 min on and off periodically). Each experiment was operated with a constant voltage gradient of 1 V/cm in a reactor (1 × 1 × 0.18 m) using real saline soil during 9 weeks. The removal efficiency of anions in the conventional DC system was slightly higher than that of the pulse system. However, there was less of a difference in removal efficiency between the conventional DC and pulse systems, except with NO3-. The removal efficiency of cations in the conventional DC system was higher than that of the pulse system, which is beneficial for cultivation because cations such as Na ⁺, Mg²⁺ and K⁺ are essential elements for crop growth. Even though the pulsed current removed slightly fewer salts and less electrical conductivity than conventional power, the system lowered the electrical energy consumption to 64% and effectively prevented pH changes and electrode corrosion compared with conventional power. Therefore, pulsed current could be an effective technique for electrokinetic restoration of saline soil.