This project deals with the challenge of optimizing the maintenance of pumped sewer
systems. Recently, a method to monitor the health condition of a pump system
based on pressure measurements has been developed. The method is inspired by
electrocardiography, as the pressure measurements during transients are converted
to knowledge about the condition of both the pump and the pipeline. Currently, the
monitoring is used to reduce maintenance costs by enabling a demand-controlled
maintenance program. In this project, the method is used to optimize the energy
consumption of pump systems. An analysis of the current operation of two typical
Danish pumped sewer mains in Kongerslev and Tvis, Denmark shows that it is
possible to reduce the energy consumption by 60% in Tvis, if the flow velocity
is reduced to 0,5m/s . However, normal engineering practice is to avoid such low
velocities as they are associated with a risk of insuffcient self-cleaning. In the project,
the possibility of reducing the flow velocity without increasing the roughness is
investigated, when a hydraulic flushing of the pipeline is implemented. In such a
pump operation, the pressure measurements serve as an indicator for the need for
?ushing. However, an analysis of the efficiency of a regular hydraulic flushing of a
pipeline indicates that the typical pump sump is too small to facilitate an e?ective
cleaning of the pipe. Therefore, hydraulic ?ushing can only be implemented in an
energy optimization, if the current standards for pump system design are altered.
Another widespread issue with the long pumped sewer systems is the formation
of hydrogen sulfide. In this project, the effectiveness of adding pressurized air to
the pipeline as a means for reducing hydrogen sulfide formation is investigated. The
analysis concludes that air injection in certain pipelines is a cost-effective solution but
cannot be considered a general means, as the air in some pipelines causes operational
issues. In the last part of the project, commercial CFD-software is used to analyse
and optimize the self-cleaning ability of two pump sumps. The use of CFD-software
shows a potential to improve pump sump design. However, CFD-simulations will
be particularly useful in the design of pump sumps if a new solution method is
implemented. The method should enable the simulation of free surface ?ows without
the current requirements to describe the air phase