Thesis defence J.A.C. van Bijnen: sewer systems

22 June 2018 12:30 - Location: Aula, TU Delft - By: webredactie

The impact of sewer condition on the performance of sewer systems. Promotor 1: Prof.dr.ir. F.H.L.R. Clemens (CiTG); Promotor 2: Dr.ir. J.G. Langeveld (CiTG).

Sewer systems are underground infrastructure networks, comprising pipes, manholes and ancillary works, to collect and transport rainfall runoff and sewage to wastewater treatment plants. Systems protect society from exposure to faecal contamination and flooding of urban areas due to heavy storm events. Furthermore, protection of the environment (surface water and groundwater) is a main prerequisite. Consequently, it is important to maintain the defined service level over time.

In the Netherlands, 1,5 billion euro is spent annually to maintain and operate sewer systems. Increasingly, risk based sewer asset management is being advocated to balance the required budget and the provided service to society. A prerequisite for risk-based sewer asset management is to be able to relate the condition of the infrastructure with infrastructure performance and consequently, the provided service level.

In the research project, a new method has been developed to identify in sewer defects by using advanced model calibration. In addition, it is demonstrated that currently, there is a big gap between theoretical system performance and system performance in reality due to the condition of the sewers. Consequently, the return period for urban flooding decreases from 2 years to 1 year on average with as a negative side effect an increase in the infection probability. Improved sewer maintenance or more robust sewer design could be applied to circumvent this issue. The results show that risk-based sewer asset management should focus more on risks and performance rather than on cost savings.

More information?

For access to theses by the PhD students you can have a look in TU Delft Repository, the digital storage of publications of TU Delft. Theses will be available within a few weeks after the actual thesis defence.