Nitrate pollution control in different soils by electrokinetic

Laboratory experiments were conducted to determine if nitrate transport in soils can be controlled using electrokinetic (EK) technology. Nitrate concentration, pH, electrical potential and soil water content were measured in soil column tests with three soils at different distances from the anode and at desired times. Constant electrical current was applied to the system for 9 hrs and continued for a total of 48 hrs. The results showed that in sandy soils nitrate can be strongly retained near the anode, even against gravity and drainage effects. When the percentage of clay in the soil was increased, the EK effect was decreased; due to the increase of fine clay particles both the transports of ions and the water were inhibited. The loam soil showed slight increase of nitrate concentration near the anode, but the clay soil showed no change. An increase of pH near the cathode was seen in all soils. Water content measurement showed that in sandy soil, water content was higher at the bottom and lower at the top, but for loam and clay soil, the lowest water content was at the layer just above the cathode. The electrical potential required to obtain constant amperage was 97.23 V in sandy soil, 18.24 V in loamy soil and 14.22 V in clayey soil. For sandy soil, the highest potential fraction was found near the top of the column in the system, but for loam and clay soil, the highest potential portion was near the bottom, next to the cathode, suggesting that these locations were the critical zones limiting the ion transport.