Desorption and Retentivity of Filtering Materials

An experimental study of the influence of the nature of the surface of filtering material on the mechanism of attachment of suspended matters has been conducted. The results indicate that the retentivity, defined as: r = (M_o) − m/M_o in which r = retentivity of filtering material; M_o = total quantity of suspended water retained by the filter during the filtration period; and m = quantity of suspended matter which can be recuperated by a given quantity of wash water. This can be utilized as a nondimensional intensive parameter to evaluate relative affinity of a filtering material to suspended matters. This affinity has a great influence on the duration of the effective period of filtration. The conclusions of this study, together with information obtained from a literature review, lead to a formulation of an opinion on the mechanism of filtration of water through a uniform bed of filtering materials.