DETAILS OF PROJECT PROPOSERS
Title of Project or
Research Theme
Project sponsor(s)
Residual Chlorine Modelling for Water Distribution Systems
Organisation
Name
Scottish Water
Mark Haffey
Academic supervisor
University
Name
University of Sheffield
Prof Joby Boxall
DETAILS OF THE PROJECT
Project Description
Background / rationale
Maintenance of disinfection residual within water distribution networks is a fundamental
requirement to ensure that high quality product produced at water treatment works remains
fit for human consumption. Free chlorine is a preferred disinfectant, being highly reactive.
However its very nature makes its behaviour difficult to predict and manage. Over-dosing
results in taste and odour issues, potential by-product formation and costs implication while
under-dosing results in inadequate protection of public health and well being. Maintaining the
correct balance in such a dynamic system presents a significant challenge for all water
companies
This project has been developed in conjunction with a sister project proposal with the
Cranfield University on ‘Modelling CT’. This collaborative research will deliver an integrated
picture on the management and impact of Chlorine from works to tap. Only by linking these
two projects will a more holistic chlorine management solution be realised.
Research challenge / questions
To improve understanding, modelling and practice relating to chlorine within water
distribution networks.
Methodology
1. Literature review of chlorine kinetics and modelling.
2. Training in infoworks – leading commercial 1D network modelling software, use by the
majority of UK water companies
3. Exploration of EPANET MSX - the latest research development from USEPA that enable the
introduction of maths to describe reactions and interactions within networks. Freeware.
4. Laboratory chlorine tests.
4.1 - bulk water chlorine. Jar tests to fully characterised bulk water demand.
4.2 - wall demand tests using exhumed pipe samples. This is perceived as a logistically
complex task, but highly desirable contributing greatly to novelty, adventure and advance of
the work – interaction with sub-contracts will be essential here. Carefully selected
representative samples only will be tested. Chlorine decay to be monitored over time using a
simple bench top re-circulating facility. There is potential for added value for biofilm research
associated with this subtask.
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5. Field chlorine tests.
5.1 - Tracer tests to confirm accuracy of model hydraulics. Salt tracers, detected using
conductivity probes. Accurate displacement pump required for injection. Dose well below
taste limits still provides accurate detection.
5.2 - Chlorine monitoring in the network. To make use of online chlorine monitors. Monitoring
of each network to be for a number of weeks/months. If possible chlorine does to be adjusted
during this period. Monitoring to be repeat for some different networks (ie asset types, source
water characteristics, network size/complexity). Some network to be revisited to explore
temperature and time effects.
6 Modelling
6.1 Data analysis - application of soft computing to determine multi variate trends and
patterns. Such as Self Organising Maps and Support Vector Machines. Apply to data from 4
and 5,
6.2 Network model fitting - application of 2 and 3 to data from 4 and 5 informed by 6.1.
7 Iteration and interaction of 4.2, 5 and 6.
Anticipated outcomes & benefits for the sponsoring organisation and other stakeholders
Outcomes will deliver a better understanding and model of what controls chlorine demand in
our networks - this will subsequently allow us to predict demand through network profiles
and also in identifying/quantifying what impact different interventions can have. Further, this
knowledge will support in:

providing the basis to inform future designs and investments,

assessing and determining the range of mitigation measures that may be taken to
maintain compliance; and,

further provide invaluable contributions in the development of disinfection policies, where
in conjunction with the ‘Modelling CT’ proposal we will be able to deliver a more holistic
chlorine management solution.
This project will have strong added values from association and interaction with ‘modelling CT’
project, also with Scottish water. It is anticipated that this projects will be run with some joint
steering meetings. Overlap will range from literature review, to methods (such as tracer
tests), to analysis techniques.
Scientific contribution of the project together with any other innovative aspects.
Contribution to the general field of chlorine modelling, including particular association with
network profiles and the predicted quantification of the impacts that different interventions
can have within a network.
Business or management element that is to be tackled in the research.
Delivering a more holistic chlorine management solution lies at the heart of this and the sister
project. Developing our knowledge in this area will aid us in a range of key business
objectives – from the further development of the intelligence required to support our
Intelligent Control Centre through to supporting our network/development guys and
their ability to assess the impact of any changes and potential mitigation options to
proposals – e.g. secondary chlorination locations.
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