Graph-based identification of critical elements in urban water infrastructure

The purpose of this thesis was to develop and demonstrate methods for determining the criticality of elements in networks. The impact failures could have on the network performance was its primary focus. A second objective was to determine whether the developed method could be applied successfully based on network characteristics. To achieve...

Ageing of plastic pipes in urban drainage systems

Plastic materials, such as PVC and HDPE, have become dominant construction materials for sewer systems, mainly due to their reputed chemical resistance. Nonetheless, plastic sewer pipes have operated for decades in a hostile environment, raising concern among sewer managers over the longevity of their drainage systems. Therefore, the main aim of...

On the build-up of storm water solids in gully pots

A substantial part of urban surfaces is to some extent impermeable. Rainfall on these areas turns into runoff, which mobilises solids present on these surfaces. This runoff is removed from urban built areas by different type of drainage systems via gully pots. The objective of a gully pot is twofold, namely 1) to convey runoff to the drainage...

On the free-surface vortex driven motion of buoyant particles

This is an experimental and theoretical research on the motion of buoyant particles in the flow of a free-surface vortex at moderate to high particle Reynolds numbers.

Domestic Slurry Hydraulics in Transport

Domestic wastewater streams from households implemented with source separation, vacuum toilets, and food waste disposers are highly concentrated with respect to the total suspended solids. The concentrated domestic slurries (CDS), which generally consist of faecal matter, urine, ground kitchen waste (GKW) and water, need to be transported from...

Uncertainty analysis in integrated catchment modelling

The adoption of increasingly restrictive water quality standards is directed to maintain natural ecosystems in a good status. Complying with such standards requires significant investments in water infrastructure and operations. Consequently, mathematical simulation is usually applied to assist in the decision-making process for such large-scale...

The impact of sewer condition on the performance of sewer systems

Sewer systems are underground infrastructure networks, comprising pipes, manholes and ancillary works, that collect and transport rainfall runoff and sewage to wastewater treatment plants. These systems protect society from exposure to faecal contamination and flooding of urban areas due to heavy storm events to a predefined service level....

Performance evaluation of real time control in urban wastewater systems

This thesis deals with real time control (RTC) in urban wastewater systems, where<br/>urban wastewater systems are defined as a combination of combined sewer systems and wastewater treatment plants (WWTPs). Urban wastewater systems discharge, through combined sewer over flows (CSOs) and WWTP effluent, onto the receiving waters. Receiving waters...

A statistical approach to guide the management of the anterior part of the sewer system

The anterior part of the sewer system consists of a system of gully pots and lateral (house) connections that drain to main sewers. The total length of lateral house connections can be similar to the total length of the sewers they drain to. In addition, there are 7 million gully pots with corresponding lateral connections in the Netherlands...

On decision-making for sewer replacement

Analysis of how decisions for sewer replacement are made in practice. Extra attention goes to the role of information quality and collaboration between stakeholders. The applied research methods are interviews, surveys and a serious game.

Assessment Methods for Structural and Hydraulic Properties of Concrete Sewer Pipes

Asset management is a tool for maintaining the required level of serviceability of urban drainage systems, which are costly to construct and in some cases even more costly to replace. The required asset management effort to achieve a certain level of service is unclear due to a limited knowledge on sewer failure mechanisms and due to scarcity of...

On rainstorm damage to building structure and content

Monitoring ground settlement to guide sewer asset management

The study into the influence of (differential) settlement on the functioning of sewer systems was initiated to search for additional criteria to make sewer pipe replacement decisions more sensible. For this Amsterdam was used as a case study. Like many megacities (e.g. Jakarta, Bangkok, Tokyo, Shanghai), Amsterdam is situated in a delta area. As...

Monitoring as a tool for the assessment of wastewater quality dynamics

The wastewater system in the Netherlands comprises approximately 100,000 km of sewer pipes and more than 350 wastewater treatment plants (wwtp). The system collects and treats the majority of domestic and industrial wastewater. A small amount of untreated wastewater, however, is occasionally discharged to rivers and lakes, often resulting in a...

Co-current air-water flow in downward sloping pipes: Transport of capacity reducing gas pockets in wastewater mains

Air-water flow is an undesired condition in many systems for the transportation of water or wastewater. Air in storm water tunnels may get trapped and negatively affect the system. Air pockets in hydropower tunnels or sewers may cause blow-back events and inadmissible pressure spikes. Water pipes and wastewater pressure mains in particular are...

Quantitative risk analysis of urban flooding in lowland areas

Urban flood risk analyses suffer from a lack of quantitative historical data on flooding incidents. Data collection takes place on an ad hoc basis and is usually restricted to severe events. The resulting data deficiency renders quantitative assessment of urban flood risks uncertain. The study reported in this thesis reviews existing approaches...

Interactions within wastewater systems

Wastewater systems consist of sewer systems and wastewater treatment works. As the performance of a wastewater treatment plant is affected by the characteristics, i.e. operation and design, of the contributing sewer systems, knowledge of the interactions between sewers and wastewater treatment works is very important when trying to understand...

Probabilistic assessment of the performance of combined sewer systems