Particle Size and Clogging of Granular Media Permeated with Leachate

Abstract

The effect of particle size (4-, 6-, and 15-mm nominal sizes) on the rate of clogging of columns of porous media permeated with municipal solid-waste leachate is examined. Clogging is shown to be more localized over a small volume of the porous media near the influent end of the column for smaller particles than for larger particles, where clogging was more uniformly distributed along the column. This is attributed to the greater surface area per unit volume of smaller particles allowing greater biofilm growth per unit volume. This increased the reduction in chemical oxygen demand (COD) and caused greater deposition of inorganic clog material per unit length of column than for larger particles. The distribution of methanogenic bacteria was found to closely correspond to the zones of most severe clogging. The bulk density of clog material is shown to be between 1.6 and 1.8 Mg/m