Loughborough University
Leicestershire, UK
LE11 3TU
+44 (0)1509 222222
Loughborough University

Centre for Innovative and Collaborative Construction Engineering

Current research engineers

Vasiliki Koutsospyrou


Novel, non-intrusive microwave sensors


Dynamic Flow Technologies Limited (DFTL)


Prof Graham Sander
Dr Ashraf El-Hamalawi

Martin Croft
Duncan Wallis

Director of Research:
Dr Chris Goodier

Research Period:

2014 - 2018


Novel, non-intrusive microwave sensors

Company Background:

Dynamic Flow Technologies is a start-up company based in Holywell Park with and serving the major water utilities. The business plan and portfolio includes a range of innovative sensors at various stages of development. There is a major need for better and more reliable sensors to improve the performance of complex water networks. For a large utility this will include over 50,000km of buried pipes of various materials, diameters, interconnections and duties. The increasing costs of this infrastructure and the need to avoid wastage in an era of water scarcity has led to a demand for improvements to monitoring. This has created a major new market for both qualitative and quantitative monitoring. Dynamic Flow Technologies has been set up to fulfil this need with the financial support of Severn Trent and Wessex Water together with Siemens Instrumentation.

Current state-of-the-art:

At present non-intrusive flow measurement is by electromagnetic or laser Doppler measurements. These require either full pipes or clear fluid; wastewater flows are often measured as open channel levels by ultrasound or less reliably pressure transducers. Open channel or permanently full pipes are not practical in most gravity sewers and the lack of available measurements is a real difficulty in accurate control and billing in complex networks. This project is to research microwave analysers for which international patents are pending. It is unique in its use of microwave reflection and absorption for measuring flow and composition of wastewater.

The system will be based around transceiver electronics, configured to transmit either a narrow or wideband microwave signal into the water pipe and then receive a multitude of reflections. This will be coupled with processing circuitry to analyse the various reflections of the microwave signal, for example, height of water in the pipe and then converting this data into wetted area to determine volume. It is anticipated that this function can also be used to alert for blockages in the pipe – an alarm can be triggered if the processing circuitry determine the height of wastewater in the pipe has been constant for longer than a threshold period of time.

It should be possible to programme the device to transmit readings automatically and remotely to be analysed off site. This would reduce the need to service the instrument for manual calibration and data validation.

Preliminary research in the Physics Department at Leicester University has also established that measurements of the chemical characteristics of the water in the pipe could be determined from the frequency of microwave absorption. The energy absorbed caused molecular rotation which was in discrete quantum steps of excitation. The rotation absorption spectrum of a molecule was dependant on a dipole moment between its centre of mass and charge. This means that the functional groups in organic compounds will have a unique uneven charge distribution signature across the molecule which can be analysed from the microwave rotational spectra.

Data on the microwave absorption spectra of some simple organics (alkanes, alkenes, alcohols, aldehydes, ketones and carboxylic acids) has been published in the research literature. Many of these are common breakdown products of the more complex organics found in wastewater. It should therefore be possible to use the processing circuitry pre-programmed to recognise specific impurities by their unique signature, removing the routine need for manual chemical analysis. There is also the possibility of identifying target priority pollutants in clean water, such as the disinfection by-products, plasticizers and pharmaceutical residues. This is speculative and requires research and well controlled experiments to better understand the balance of types of interactions (reflectance/absorption) between water and microwaves. This will be a significant contribution to fundamental knowledge. Little is known at the moment about interferences and interactions between solids, sediment, biofilms, organic/inorganic materials and pipe materials. Microwaves offer the potential of increasing the range of new non-invasive sensors for both qualitative and quantitative analysis.

Aims and Objectives:

Research on the fundamentals of the interactions of the new meter microwaves with water and wastewater. Development of a new meter for quantitative and qualitative water analysis. Validation of the new meter supported with basic theory.


Understand the effectiveness and range of potential applications of microwaves for water analysis:

1. Measure reflectance performance with different pipe diameters and materials (plastics).

2. Predict the impact of solids deposition or corrosion (wetted perimeter) and surges on microwave signals.

3. Understand the effect of pipe features; connections and geometry (bends, junctions) on microwave signals.

4. Carry out basic experimental research on the microwave adsorption spectra of different particle sizes and composition (organic/inorganic).

5. Research on the microwave absorption signature of priority pollutants in water and wastewater. These would include residual carboxylic acids both volatile and complex (e.g. humic, fulvics) and other indicator compounds such as mercaptans and amines.

6. Investigations of the sensitivity of microwave signals would also be carried out on persistent problem compounds such as the plasticizers, pesticides and pharmaceutics in clean water.

Expected Benefits and Outcomes:

The outcome is to develop more reliable sensors and meters to allow better control of these complex pipe distribution systems. This is an urgent requirement primarily to improve environmental quality, resilience to climate change, system deterioration and charging for services.

This is an important market opportunity existing invasive sensors are unreliable and not suitable for qualitative analysis.

The research is expected to generate a greater range of commercially valuable analytical tools. Thus improving the cost effectiveness of monitoring and control of complex process systems.

Independent validation of novel sensors and techniques linked to basic theory of flow and water quality.

Understanding the effectiveness and benefits of new methods over a range of field and commercial conditions.




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+44 (0)1509 222623

The Centre Administrator
Loughborough University
LE11 3TU

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