Suspended solids within sewers: an experimental study

A precise determination of the pollutant loads processed through the sewer networks is required for legal, environmental and management reasons. Such a determination requires a good evaluation of concentrations, which is not an easy task because samplers or sensors can perform measurements in a cross-sectional area of only a few locations, and this local information must then be extrapolated across the whole cross-sectional area of the sewer network. This latter step is problematical. A great deal of attention must be given to suspended solids because they are prone to settle and display heterogeneous concentration patterns. A two-dimensional sampler has been designed to measure the variation of suspended solids concentration throughout a cross-sectional area. This paper presents the principles upon which the conception of this experimental device was based and the building process. Experimental results are presented and discussed.