Sonic Characterisation of Change in Sewer Networks

Water companies need enhanced information in two key areas to manage the current and strategic maintenance of sewers efficiently, which relates strongly to the operational and structural conditions and the rate of deterioration. As flooding caused by hydraulic overload can be tackled through capital investment, flooding other causes becomes increasingly significant as a failure of a service with heavy environmental, economical and social impacts. In many situations, it is more efficient to maintain the operational condition of a sewer regularly, rather then replace it in the case of structural collapse. Companies are now looking for new ways of reducing these incidents, however, the existing methods of sewer analysis and CCTV survey remain largely time-consuming and subjective.Recently, a series of acoustic experiments has been carried out by the investigators in a drained sewer pipe to identify the evolution of a small blockage. These initial results suggest that the acoustic signature of the sewer can be used to detect the location and extent of a minor change in the cross-section of a large-diameter pipe. Although, acoustic instruments have already been developed to determine variations of the cross-section of narrow pipes (e.g. musical instruments), there have been no systematic studies into the reconstruction of the cross-section profile of a realistic sewer pipe. The purpose of this project is to develop a novel practical and efficient acoustic technique to monitor the evolution of operation and structural conditions in live sewer networks.