EFFECTIVE NITRATE CONTROL WITH ELECTROKINETICS IN SANDY SOIL

摘要

Nitrate contamination of surface and ground water is a problem worldwide. Nitrate in drinking water presents a human health risk. The major source of nitrate contamination is believed to be nitrogen fertilizer from agricultural fields. Best Management Practices have been developed to guide fertilizer use and minimize nitrogen losses, but they do not address control of nitrate movement from the crop root zone. It is proposed that electrokinetics, an in-situ method, could be used to control nitrate movement, retaining it near the root zone. This article reports results from a study on nitrate movement and pH changes in a vertical, partially saturated sandy soil column subjected to an electrical current. The highest measured nitrate concentration (7155 mg/L) was within 5 mm of the anode after application of a 6 h 80 mA current. The nitrate concentration at the cathode was 1/5 of the inflow solute concentration. The pH was 11 near the cathode, 3.5 near the anode, and showed little change in intermediate layers. Studies of different nitrate concentrations and electrical current levels suggest that 80 mA electrical current applied for 6 h duration might effectively control nitrate migration in similar sandy soil conditions.