The feasibility of electrophoretic repair of impoundment leaks

Abstract

Geomembrane liners installed in surface industrial impoundment may be impaired due to physical damage, improper installation, abnormal materials, construction cracks, or human mistakes during operation. Conventional repair methods, which involve finding, repairing and testing the leaks, are tedious, expensive, and dangerous to workers. Electrophoretic repair technique is an innovative, economic, and safe method to repair the leakage of impoundments. A suspension of clay particles is induced to the impoundment. The cathode is placed inside and the anode is placed outside the impoundment. An electric field is imposed externally across the leaks of geomembrane liner. The negative charged clay particles are repelled by the cathode and attracted by the anode toward the leak. Thus, clay accumulates in and near the leaks, thereby sealing the liner. This thesis presents the results of cake formation tests conducted to induce electrolyte (NaCl), four organic compounds (methanol, phenol, chloroform, and toluene) and mixture into the clay suspension. The effect of the presence of NaCl and four different organic compounds was investigated. The results of cake formation tests indicate that the cake decreasing rate was dictated by: (1) additions of NaCl which reduced the height and diameter of clay cake due to rapid flocculation; and (2) polar organic liquids with high dielectric constants, such as methanol and phenol, which affected the size of clay cake less than non-polar organic liquids with low dielectric constants.