GROSS SOLIDS MOVEMENT IN SEWERS - LABORATORY STUDIES AS A BASIS FOR AMODEL

A simple model of gross solids' movement in sewers is proposed, based upon the results of studies of part-full pipe flow in two laboratory i nstallations, under steady and unsteady flow conditions. The model cov ers advection and deposition, and is intended as one component in a co mprehensive model of the behaviour of gross solids in sewers, Such a m odel is needed because gross solids are not included in the currently available sewer-flow quality models, even though they can cause pollut ion which is of particular concern to the public. The paper describes the laboratory studies and their results. It sets out the principles o f the proposed model and explains why these differ from existing model s of dissolved and fine suspended pollutants.