Soil Clogging Phenomena in Vertical Flow

Particle movement and deposition are known to be serious problems for filtration systems. Dramatic reductions in filter permeability are observed in such cases as consequence of deposition of fine particles transported by fluid in the porous media. Accumulation and deposition of suspended solids in porous media can ultimately lead to clogging. The main purpose of this paper is to assess some relations governing filtration behaviour. Packed sand columns were used to investigate soil clogging, focusing on the questions of identification and the description of porosity damage. Some laboratory filtration tests were carried out using various granular sizes of filters and changes in soil water retention, pore size distribution, and saturated hydraulic conductivity due particle deposition were investigated. The results obtained show that filtration and likely clogging depend on particle concentration and flow conditions. The research results clearly show under what conditions soil clogging occurs and how to mitigate this problem. This potential for clogging has been expressed in terms of soil-type parameters used in soil physics, such as a pore damage index, which gives engineers and geo-hydrologists a tool to assess the potential for clogging in a specific soil condition. Maximum clogging occurs mainly in the upper lay of the bed and is dependent on the suspension concentration, pore structure and flow rate.