Electroosmotic Contaminant‐Removal Processes

Abstract

Theoretical fluid transport and chemical‐reaction equations are presented for one‐ and two‐dimensional fluid flow induced by an electrical field. Laboratory column and two‐dimensional model studies examine electroosmosis (EO) as a method of contaminant removal from saturated clay. Experimental results are compared with theoretical fluid transport and chemical‐reaction relationships. Nutrient‐transport processes are evaluated as a precursor to potential in situ biological treatment of organic contaminants in fine‐grained soil. Laboratory studies are conducted with clay box models and with glass columns packed with low hydraulic‐conductivity soil, including Kaolin, glacial tills, and mixtures of sand and clay. Experimentation shows that saturated clay behaves as an electrochemical cell. Chemical reactions are driven by induced currents. Average flow rates in three‐dimensional systems can be predicted from soil column studies. Electroosmotic conductivity is proportional to soil porosity. Nutrient‐transport studies show the feasibility of nitrogen transport, and the inability to transport phosphorus through a soil medium. Nitrates are reduced to ammonia and phosphorus precipitated at column anodes.