Treatment of Sewage Sludge Using Electrokinetic Geosynthetics

The treatment and disposal of sewage sludge has, historically, included depositing to land, forming lagoons. Once deposited, these materials do not change in material characteristics, even after several decades, leaving behind a legacy of deeply deposited low strength material. These pose a potential danger to the public and a source of contamination for adjacent water courses. Several researchers have shown that electrokinetic dewatering of sludge is an efficient means of driving off water from the sludge, thus improving strengthand reducing volume. This involves the application of a D.C Voltage across the sludge, driving water under an electrical gradient from positive (anode) electrode to negative (cathode) electrode. This paper will describe laboratory and field experimentation using electrokinetic geosynthetics: polymer- based materials containing conducting elements. These have been used to minimise the problem of electrode corrosion problematic with the use of traditional, metallic electrodes. Formed as tubes, or ‘wicks’, these materials offer a potential means to dewater sewage lagoons in situ.