Effect of Various Parameters on Electrokinetic Dewatering of Saturated Clay

Electrokinetic dewatering is an effective method to remove water from saturated clay having low hydraulic conductivity. This performs better than other dewatering methods like sand drains, prefabricated vertical drains, vacuum dewatering, etc. In electrokinetic dewatering, low intensity direct current is applied across the soil layer through electrodes, thereby accelerating the flow due to changes in physio-chemical processes. In the present study, a series of laboratory experiments were performed on saturated clay collected from Lunawada region of Gujarat to study the effect of various parameters on electrokinetic dewatering. A water tight wooden box (40 cm × 40 cm × 30 cm) was used to perform the experiments. Hollow circular stainless steel tubes (length = 25 cm and inner diameter = 1.9 cm) were used as electrodes. Perforations with diameter of 5 mm were provided on electrodes at regular intervals to allow and collect water from surroundings during the experiments. Efficiency of electrokinetic dewatering was studied under variations of voltage, electrode spacing and pH. Water collected at cathode was removed manually from top at cathode, and the quantity was measured. The results confirm that dewatering efficiency increases with an increase in voltage as water flows under greater electric gradient at higher potential difference. The decrease in centre to centre spacing between anode and cathode causes overlapping of electric field which enhances dewatering efficiency. Decrease in pH of soil causes soil to be more acidic in nature that results in less dewatering efficiency. Further, cracking patterns near anode for each series of experiments was also studied to enhance the understanding of electrokinetic dewatering. It is confirmed from the experiments that electrokinetic dewatering is greatly influenced by voltage, electrode and pH. Other parameters like electrode pattern, type of soil, type of electrodes, etc., can also be evaluated for better understanding of electrokinetic dewatering.