Characterization of sediment accumulation, erosion and transport processes in comined sewer pipes

Abstract

The analysis of the sediment accumulation, erosion and transport processes in combined sewers is a key issue within urban drainage systems. Sewer sediments represent the main source of pollution in sewer systems to the receiving environment. This thesis aims to study in detail these phenomena to propose optimal solutions that lead to sustainable urban development. To this end, the self-cleansing efficiency and the absence of blockages by gross solids in egg-shaped pipes were tested in comparison with circular sewer pipes. In addition, as a major differentiating element, a Flume Test Facility was set up to perform in-sewer deposition, erosion and transport experiments with various pipes by supplying urban wastewater. In this facility, new techniques and methodologies were developed to increase the accuracy in the measurement of the accumulation and transport of in-sewer sediments, as well as to analyse their physicochemical properties. Furthermore, experiments were also performed on small-scale models to characterise the concentration and size of suspended particles by using acoustic sensors. As a result, a large dataset was obtained to develop advanced strategies for the design, operation and maintenance of combined sewer systems.