Electrokinetic Injection of Nutrients in Layered Clay/Sand Media for Bioremediation Applications

Electrokinetic processing has been used to inject representative cationic and anionic nutrients into soil layers, which have widely different hydraulic and electrical conductivities. In this case, using parallel clay and sand layers and at a practical current density, ammonium ion concentrations reached 300-35x0 mg/L in the sand and 250–300 mg/L in the clay layer, while the respective values for sulfate ion were 900–1,000mg/L and 1,000–1,200mg/L. This demonstrates the potential for bio-electrokinetic enhancement by nutrient injection for those sites which cannot be bioremediated by natural attenuation alone. Although considerable electroosmosis occurred at the neutral pH of the system, the anions could be injected upstream about one meter by 1,028 hours of processing. Both the power consumption costs and the process rates arepracticable for the injection of such process additives.