Annual report Chair on Drinking Water Engineering 2007 - TU Delft

INTEGRATED MODELING OF OZONATION FOR OPTIMIZATION OF DRINKING
WATER TREATMENT
Research objectives
The research has two objectives: to determine the objectives for optimization of operation of drinking water treatment
plants and to develop an integrated model for ozonation that can be used for operational support and process
control. The model has to be able to function as a part of an integrated model for the entire Weesperkarspel
drinking water treatment plant of Waternet.
Project outline
Introduction
In the Netherlands, drinking water treatment plants are robust and designs are based on the performance of
individual processes with pre-set boundary conditions. In operation of drinking water treatment plants, the processes
are usually optimized individually on the basis of “rules of thumb” and operator knowledge and experience.
However, changes in operational conditions of individual processes can affect subsequent processes and an optimal
operation, which can include a number of water quality parameters, costs and environmental impact, is different
for every operator. It is assumed that an integrated approach to the entire treatment plant can lead to a more
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an instrument for operational support and for process control to further improve the operation of a drinking water
treatment plant, making maximal use of the installed infrastructure and postponing new investments.
Approach
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it describes integrated modeling of ozonation. Ozonation plays a key role in integrated modeling of the treatment
plants of Waternet, water cycle company for Amsterdam and surrounding areas, that were used in case studies.
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ozonation model, experiments in different bench-scale and pilot-scale ozone installations with different natural waters
are performed. In addition different control strategies for ozonation are assessed, a new design for ozone installations
is developed, and the character and removal of natural organic matter (NOM) prior to ozonation is studied.
Results
The objective for integrated optimization of the operation of drinking water treatment plants should be the improvement
of water quality and not an a priori reduction of environmental impact or costs. Therefore modeling efforts
focused on water quality modeling. The developed ozonation model was used for evaluating the current control strategy
of the full-scale ozone installation at Weesperkarspel and for assessing other control strategies for operational
support and process control of ozonation. It is a tool that directly shows the consequences of changes in operation
of the ozone installation. It enables water supply companies to make more objective choices for operational settings
and, thus, is a valuable tool for controlling the balance between disinfection, bromate (a possible carcinogenic
according to the World Health Organization) formation and AOC formation.From the experimental work and modeling
studies, the importance of the hydraulic conditions for ozonation was demonstrated. The dissolved ozone plug
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in a pre-treated side stream and dosed to the main stream just before a static mixer. Subsequently, contact time in
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48 <strong>Annual</strong> <strong>report</strong> DWE 2007