WIPAC Monthly - May 2017

WIPAC MONTHLYThe Monthly Update from Water Industry Process Automation & Control
www.wipac.org.uk Issue 5/2017 - May 2017

In this Issue
From the Editor.................................................................................................................... 3
Industry News..................................................................................................................... 4 - 11
Highlights of the news of the month from the global water industry centred around the successes of a few of the
companies in the global market.
Adopting Water 4.0?......................................................................................................... 12-13
Whether you call it Water 4.0, the Smart Water Industry or the Digital Water Industry it is a potential future for the
Water Industry. The problem is the adoption of technology has always been perceived to be slow. In this opinion piece
some of the barriers to the adoption of a Smart Future for the Water Industry are outlined.
Determination of flow rates in part filled applications using the radar method.................. 14-16
Flow rates in closed pipe applications in the Water Industry has always been challenging with a few technologies
available to cover the application. In this article by Mathia Stratyla of Nivus the use of radar technology for
measurement in part-filled pipes is outlined
Evaluation of a solid state reference electrode junction material for ISEs........................ 17-23
In this technical paper a junction material for use in ion selective electrodes is evaluated with particular reference to
the measurement of pH. This paper was provided by Refex Sensors Ltd
Workshops, Conferences & Seminars................................................................................... 24-25
The highlights of the conferences and workshops in the coming months

The picture on the front cover is the use of advanced radar rainfall monitoring for sewer prediction that is being developed in
Holland
WIPAC Monthly is a publication of the Water Industry Process Automation & Control Group. It is produced by the group
manager and WIPAC Monthly Editor, Oliver Grievson. This is a free publication for the benefit of the Water Industry and please
feel free to distribute to any who you may feel benefit.
All enquires about WIPAC Monthly, including those who want to publish news or articles within these pages, should be directed
to the publications editor, Oliver Grievson at olivergrievson@hotmail.com

From the Editor

Sitting down in the SWAN Conference this month was particularly interesting as it brought a real focus into the context
of the Smart Water Industry and some of the things that were said and one of the most poignant and simple things
that was said by Amir Peleg was right at the start of the conference as he added a most important part to the centre of
the technology triangle. For those of you who aren’t familiar with the concept it basically puts technology, processes and
people as the three key elements of adopting technological solutions and the addition at the start of the conference was
quite simply.....passion. This was followed up with a poll in one of the earlier sessions of the conference that asked the
question as to whether the audience felt that
“Adoption of data-driven technologies is not a technological challenge but rather a management challenge within water
utilities“
The resounding answer was that 81% of the gathered audience felt that it was and this rings true within the industry as a
whole as some of the companies that have adopted data-driven technologies have had inspirational leaders who have taken the decision to go down the route
of adopting technologies which provide situational awareness or technologies that provide process control based upon increased data production through
enhanced use of instrumentation. The industry is building a great number of case studies to show this and hopefully this can be turned around to highlight
the benefits of taking this approach. One of the speakers present at the conference was George Theo from Unitywater in Australia and it was through his
presentation that the gathered audience saw a huge energy and engagement in the digital or smart space and saw a fantastic potential vision of operating a
company under this sort of philosophy and where a real business head had thought about the exploitation of technology. His point of knowing when a pipe
leak was costing more than it costs to repair it is something that alot of us has thought of as something that would improve the way that we work but of course
it proves very difficult to actually do. At Unitywater it is a work in progress that is soon to be realised.
What you can take from all of this is that George Theo amongst a handful of other people in the Global Water Industry is one of a handful of truly inspirational
leaders who have the vision to exploit the “Smart” or Digital Water Industry and these are the people who are driving it forward. These are the inspirational
leaders who will engage the people element of the technological triangle. It is of course about all people within the industry to join a journey that will
transform the industry. Of course the industry is always transforming so a good question is what is different? In someways nothing, it is just the different ways
of working but as the industry moves forward in time it is challenged to work more efficiently, to keep down the costs whilst working in a tighter regulatory
environment along with external elements such as climate change whilst protecting precious water resources that are dwindling and also cope with increased
competition. The industry in someways is under a perfect storm and so to know where we are, how we’re operating and know where the next proverbial wave
is coming from can only help. This is where the technology comes in, it is where the Smart Water Industry comes in.
I’m regularly asked about “why don’t we exploit the possibilities of the smart water industry more?” and the answer lies in the fact of do we have the
inspirational leaders who can convert the possibilities into realities, do we have the people to understand the potential of the opportunities and the resources
like the newly released SWAN Smart Wastewater Network Management Tool (click here) to exploit the huge potentials that this approach has to offer...
The Smart Water Industry has come a long long way in the past six years that WIPAC has been on the scene and it will be interesting to see what the next six
years hold......
Have a good month
Oliver

Schneider Electric Teams with Microsoft to Accelerate
Development of Open IoT Applications
Schneider Electric, the global specialist in energy management and automation, today announced a major advancement in its collaboration with Microsoft
Corp. that significantly enhances the value the companies can offer businesses and organizations across multiple industries. Customers can now gain access to
multiple cloud-based applications from Schneider’s EcoStruxure architecture that utilize the full capabilities of the Azure cloud platform, as well as next-generation
capabilities like mixed reality, to bring new levels of decision making capabilities, productivity and efficiency.
The two industry leaders will accelerate the delivery of cloud-based, IoT solutions for all of Schneider Electric’s end user segments, marrying Microsoft’s experience
in the cloud with Schneider Electric’s deep domain expertise in power management, plants, machines, buildings, data centers and grids to empower companies
in a wide variety of markets to use IoT as a competitive differentiator. This includes several cloud-based applications available today driving plant, building, people
and asset optimization, with others being developed for delivery later this year and beyond.
Alliance Helps Seminole County Ensure Safe Drinking Water
The powerful combination of Schneider Electric industrial software and Azure is already enabling customers, like Seminole Country Florida, to mobilize big data
solutions for use in the field. Seminole County has dramatically improved its ability to ensure safe drinking water for its more than 440,000 residents by allowing
plant managers and operators to view plant data on mobile, handheld and tablet devices and receive critical operational data in minutes.
“By bringing together the strengths of our two companies, we can continue to make IoT valuable, delivering tangible and measurable business results, allowing
customers to tap into new data, create new insights and fuel digital transformation in their organization,” said Cyril Perducat, Executive Vice President, IoT and
Digital Transformation, Schneider Electric.
“We are thrilled to have Schneider Electric alongside Microsoft at Hannover Messe this year,” said Caglayan Arkan, General Manager of Worldwide
Manufacturing and Resources at Microsoft. “The EcoStruxure architecture is an incredible example of how, together, we empower our customers and the
outcomes they are looking to drive.”
New Mixed Reality Capabilities with Microsoft HoloLens
The open and interoperable design of the EcoStruxure architecture and the computing power of Azure will arm industrial companies specifically with easy to
integrate advanced analytics, maintenance and training solutions and empower operations and maintenance personnel with new mixed reality capabilities that
provide an enhanced user experience with digital hologram context and prescriptive actions.
Schneider Electric will continue to build HoloLens technology into its process design and simulation and enterprise asset management solutions to bring mixed
reality capabilities to its industrial maintenance, asset performance and training offerings. Provided as part of the company’s EcoStruxure for Industry solution,
this capability significantly improves personnel safety and asset performance. It also transforms training outcomes by creating an immersive experience that
exposes personnel to interactive and simulated situations and environments to help make operational decisions and investigate processes prior to interacting in
the real-world. This feature will drastically reduce time-to-competency, costly errors in the field and enable more proactive and predictive maintenance.
The relationship builds on Schneider Electric and Microsoft’s work in driving advanced analytic solutions and is part of Schneider Electric’s strategy to build an
ecosystem of industry-leading partners to advance and co-develop its EcoStruxure architecture solutions. For more information, please visit the company’s
Hannover Messe booth, Hall 11, C58 or http://www.schneider-electric.com/b2b/en/campaign/innovation/overview.jsp.
EcoStruxure is Schneider Electric’s open, interoperable, IoT-enabled system architecture delivering enhanced value around safety, reliability, efficiency,
sustainability, and connectivity for our customers. EcoStruxure leverages technologies in IoT, mobility, sensing, cloud, analytics, and cybersecurity to deliver
Innovation at Every Level including Connected Products, Edge Control, and Apps, Analytics & Services. EcoStruxure has been deployed in 450,000+ installations,
with the support of 9,000 system integrators, connecting over 1 billion devices. For more information about EcoStruxure, please read our EcoStruxure brochure.
SWAN Forum launches Smart Wastewater Network Tool
The SWAN Forum this month at their annual SWAN Forum Conference launches the SWAN Wastewater Network tool. The Tool is a further expanision of the SWAN
Interactive Architecture Tool that is product of cross-industry collaboration. The SWAN Interactive Architecture Tool allows you to navigate through smart water
solution diagrams according to your specific business drivers and challenge areas. You may click on individual technology components to learn about their function,
benefits and system requirements, as well as view informative case studies and benefit analyses.
The tool now covers Water Network Management, Energy Managment, Pressure Managment, Leak Detection, Water Quality Monitoring, Customer Metering as
well as Wastewater Network Management.
The tool includes examples of solutions, solution providers as well as case studies and benefit analysis of smart water solutions. The SWAN Smart Tool can be
reached at the following link.
Page 4
Industry News

UK software firm honoured for Australian water work
Vancouver headquartered firm Aquatic Informatics Inc. has announced that the U.S. Geological Survey, North America’s premier Earth science agency. has
officially deployed AQUARIUS Time-Series in 25 of 50 states.
The nationwide rollout program is now 50 percent successfully completed and on schedule to finalize by mid-year.
The U.S. Geological Survey (USGS) investigates the occurrence, quantity, quality, distribution, and movement of surface and underground
waters and disseminates the data to the public, State and local governments, public and private utilities, and other Federal agencies involved with
managing water resources.
AJ Leitch of Aquatic Informatics, a global leader in providing innovative software solutions for water data management and analysis, commented:
“The USGS has now migrated over 150 years of historical data into AQUARIUS Time-Series. Within months, over 50,000 measurement locations,
16,500 active gauging sites, and 3 million time series nationwide will be managed in one centralized system. These time series represent over 100
billion data points. That is Big Water Data.”
“AQUARIUS Time-Series is already live in 25 states – it is one of the most important tools in use today by the world’s leading water monitoring
organizations to produce the highest quality data efficiently and accurately.”
The USGS manages more active real-time gauging sites than any other organization in the Americas – with 16,500 stream, groundwater, and
meteorological sites. The agency selected AQUARIUS Time-Series – the USGS collects water data on a very big scale and requires a highly powerful
water data management platform to turn massive volumes of continuous water data into timely, accurate, defensible information.
By mid-year, the AQUARIUS platform will add and process over 500,000 data points per hour and publish them to the National Water Information
System (NWIS) for public access within 1 minute of transmission.
Leitch added that the AQUARIUS Time-Series is today’s most scalable water data management platform, designed to meet the needs of
environmental monitoring organizations of all sizes, from small cities to the world’s largest agencies.
AQUARIUS is the world’s preferred software platform to acquire, process, model, and publish water data. Over 500 organizations in over 50
countries use the highly scalable AQUARIUS platform which provides them with a suite of interoperable applications to manage environmental
samples, correct and analyze time series data into actionable information, and publish data for an interactive web experience.
U.S. Geological Survey opts for AQUARIUS to manage 100bn+
data points
UK software company SEAMS, in partnership with consultancy AECOM, have won a
major award for their asset management work with a water company in Australia.
ICON Water, which provides water and sewerage services to the Australian
Capital Territory, was awarded the AMCouncil Asset Management Award 2017,
recognising excellence in the management of physical assets through their life cycle
and showcasing its use of best practice asset management systems and processes.
Making use of SEAMS’ investment planning expertise and Enterprise Decision
Analytics (EDA) software, ICON Water were able to optimise their sewer asset
intervention strategy to achieve their risk, cost and performance targets over a 20-
year period. The outputs supported their dialogue with stakeholders and informed
their 2018-2023 regulated sewer investment plan.
Richard Hawkins, Accounts Director at SEAMS, said: “We were thrilled to be selected
by ICON Water to work with them and AECOM on this project, and for ICON Water
to win this award with our software makes us immensely proud. We’ve invested a lot of time and energy into developing game-changing technology that’s
unique in its field and this award means a lot.”
Andrew Behn, Project Lead at ICON Water, said: “For Icon Water, this approach has delivered clear articulation and understanding of the balance of cost, risk,
and performance with regard to our sewer network. The application of SEAMS’ EDA is the first of its kind in Australia.
“The new processes and systems, delivered in partnership with SEAMS and AECOM has helped us immensely in identifying and determining various
impacts on levels of services into the future and overall benefits and costs under a number of different investment and intervention scenarios. This award is
recognition of the benefits of using best practice asset investment planning.”
SEAMS was founded in Sheffield, UK in 2002 and has since grown to become one of the UK’s leading asset management software providers, working with
infrastructure based organisations across the globe to help reduce costs and improve service.
Page 5

Accredited Calm Network Operators Passes 6,000 Mark
An online training initiative designed to reduce human error in the way hydrants, valves and pumps are operated has certified over 6,000 water network
operators. Aquam’s Calm Network Training is accredited by the Institute of Water and ensures that candidates achieve an understanding of the causes of
transient surge in the water network.
Research shows that human error in how hydrants, valves and pumps are operated is a major cause of surge effects in water supply networks. Surge is a major
cause of leaks and bursts in pipe infrastructure.
United Utilities (UU) was first to take up Aquam’s online Calm Network Training after launch of the scheme in 2014. The water company made it mandatory for
its contractors to complete the course, which involves a video tutorial and multiple-choice assessment. Over 3,000 operators of UU’s potable water network
have achieved certification to date.
Severn Trent Water has also made Calm Network Training mandatory and has trained over 1,600 users of its networks. Eight other UK utilities have also taken
advantage of the comprehensive and flexible training programme.
The benefits of this training go far beyond reducing surges, they include:
• Increased lifespan of existing infrastructure
• Reduced leakage and water wastage
• Fewer incidents of discolouration and contamination of the water supply caused by ingress
• Fewer customer complaints about leakage, water quality and supply interruptions
• Reduced risk of pollution from burst main run-off to water courses
• Reduced traffic disruption caused by leak repair
• Significant cost reductions
Aquam consultant Roman Boryslawskyj said, “The good news is that much of the harm done to pipe infrastructure can be avoided by modifying the way the
network is operated. This can be achieved by ensuring operators are thoroughly trained, which utilities must do under their duty of care.
“It’s about protecting the network by operating in a calm environment; then you don’t disrupt customers. Each burst attracts an average of 35 complaints and
costs £1,000 a time – and that’s just an average cost.”
Ken Lacey, technical support officer - water regulations, United Utilities said, “We are delighted to be leading the field in training network operators to manage
our infrastructure carefully and safely. The Calm Network Training course offered by Aquam can be undertaken by our own staff, our partners and other users
of the network wherever they are and at whatever time suits them.
“We have already seen the benefits in terms of reduced customer contacts and fewer bursts and leaks.”
Dan Littlewood, senior technician, Severn Trent Water said, “We are already seeing the benefits of training users of our networks to do so safely and calmly.
This is important not only to prevent damage to the pipes and prevent leakage, but also to maintain water quality and avoid disruption to customers and the
wider public.”
Phil Walker, water services director, Aquam, said, “I am delighted that the online Calm Networks Training course developed by Aquam has proven so popular
with utilities and contractors. The regulatory pressure is on to improve customer service and reduce supply interruptions, while simultaneously keeping bills
low.
“Calm Networks Training helps our utility clients reduce leakage, improve water quality, preserve pipework and cut costs. The benefit is on-going too, with best
practice becoming embedded in those utilities that invest in routine training of standpipe operations staff throughout their supply chain and customer base.”
He added, “At Aquam we also manage licensed standpipes for many UK utilities, so we feel we have a duty to help ensure that operators of the network know
what they’re doing with this kit.”
Badger Meter to acquire D-Flow Technology
Badger Meter Inc. announced it has signed a definitive agreement to acquire D-Flow Technology AB of Luleå, Sweden, for approximately $23 million in cash.
D-Flow Technology is a knowledge-based company specializing in ultrasonic technology, primarily for flow measurement.
“There is a growing acceptance of ultrasonic technology within the municipal water market. We believe the D-Flow Technology will strengthen our position in
ultrasonic flow measurement by enabling us to further enhance our existing E-Series® Ultrasonic product line, lower production costs and provide a platform
for the continuing advancement of our ultrasonic capabilities,” said Richard A. Meeusen, chairman, president and chief executive officer of Badger Meter.
“The D-Flow Technology acquisition is similar to our acquisition of Aquacue Inc. in 2013, which enabled us to integrate Aquacue’s technology into our ORION®
Cellular radios. We believe there are similar opportunities between Badger Meter and D-Flow Technology in the ultrasonic flow measurement space. Also
similar to Aquacue, D-Flow Technology’s facilities in Luleå, Sweden, will become a Badger Meter technology center,”added Meeusen.
Page 6

Grundfos & TaKaDu join forces to tap growing digital water
market
Can pressure management and intelligent networks help tackle the issue of leakage?
“Any water network is going to have leaks but what the water companies need to know is which are the important ones that need to be fixed now,” says Alan
Cunningham, Servelec Technologies’ technical director, network management, leakage and demand. “It’s all about prioritising issues and whether a major
event is going to cause a problem.”
Cunningham is discussing the merits for water companies to use intelligent systems to manage and optimise their water supply (and even wastewater)
networks. “Companies have tradition-ally responded to events such as bursts in the network by reactively responding to customer calls informing them that
they’ve got a leak in their street or there’s no water pressure; investigating that problem by manual interrogation of their systems; and sending people out to
site, putting a lot of manual resources in.
“The idea of smart pieces of software like our FlowSure is that they provide the water companies with the information they need to be proactive. They are
provided with the minimum ability that they need in order to diagnose, mitigate and resolve those problems before they have real impact on customers.”
Servelec Technologies’ FlowSure is a self-learning anomaly detection software that helps to identify and predict network events to enable companies to prevent
rather than respond to major events.
It uses readily available real-time data and smart algorithms operating in an Artificial Neural Network to automatically identify when a large burst or other
significant event is happening, or is about to occur, in a network. It features a smart alarm system that learns the acceptable level of tolerance for any given
signal. Rather than working to pre-set thresholds, the system teaches itself from pre-installed data what is and is not usual and acceptable within a network’s
telemetry data.
FlowSure sets and continuously adapts its own thresholds and reports anomalies against these learnt behaviours.
“As well as providing the data telemetry around flows and pressures, FlowSure provides maps of the network with prioritised locations, street map views,
network pipe views so contractors can go to the priority places,” says Cunningham.
Mark Hinton, business optimisation director at Servelec Technologies, adds: “There’s an innovation agenda which Flowsure as a product speaks to, and because
it demonstrably saves money as well through just being more smart. It allows companies to be a lot more efficient in the way they go about it and actually
demonstrates how they can avoid in the wastewater sector, for example, pollution events and things like that which have quite heavy fine structures, which
means FlowSure more than pays for itself within a matter of months.”
However, Hinton believes that while the business case for intelligent systems is justified, the water companies are on a journey of cultural shift. “Some of
the story is about having an end-to-end leakage detection system with all the bits in place,” says Hinton, “but clients don’t often procure that way. They’ll do
different bits of it and connect up to whatever they have. They need to do something holistic with their whole systems, which we can provide; our end-to-end
solution includes telemetry hardware, scalable SCADA and optimisation software.”
Hinton says: “A big part of being smart is the prediction aspect of using tools like FlowSure rather than just detection, and a big part of it is being more smart
about the controlled environment. Often, companies can be inundated with a snowstorm of alarms, for example, and are not sure what to do in terms of pri-
oritising them. FlowSure allows them to be much more intelligent in the way that they prioritise that.”
Hinton concludes: “Our experience is that there is interest in the leakage arena in companies. It’s one of the areas they’ve been looking to spend some money
on but they’re adapting to being more smart, and there’s a degree of inertia going forward. It is starting to happen for sure, in our view.”
Being intelligent, the smart thing to do
Page 7
Danish pump giant Grundfos has partnered with Israeli company TaKaDu to tap into the growing smart water management market.
The two companies are running a joint pilot project at Danish water utility Frederikshavn Forsyning where high-tech solutions are employed and tested in a
“live” environment.
It is hoped that the partnership will be able to help utilities to fulfil new operational targets for saving energy and water, as well as managing water network
assets in the most economical way.
The partnership will leverage TaKaDu’s experience of using cloud-based advanced software to detect anomalies in a utility’s water supply, together with
Grundfos’s work on addressing demand driven distribution.
Kenth Hvid Nielsen, group vice president, global water utility, Grundfos said that the partnership “accelerates our efforts in the digitalisation journey, and
allows us to speed up the process of providing our customers with best-in-class, data driven solutions”.
Amir Peleg, founder and CEO of TaKaDu, said: “We are very excited to partner with Grundfos in the global water market, and expand our comprehensive
event management solution to new dimensions of data, related to energy and network operations. Data analytics yields a wide spectrum of benefits, and we
are confident that this partnership will boost efficiency of both water and energy.”

Adoption of Smart Water technologies remains a Utility
Management Challenge
The smart water market is growing, with companies entering and partnerships being forged yet convincing utilities to adopt new technologies continues to
remain a challenge.
During the Smart Water Networks Forum (SWAN) annual conference held in London this week, interactive poll questions were sent to the audience through a
smartphone app.
Attendees were asked if they agreed or disagreed with the following statement: “Adoption of data-driven technologies is not a technological challenge but rather
a management challenge within utilities.”
A total of 81% of people who voted agreed with the statement, suggesting that while the technology has been developed to enable smarter water networks,
there remains a challenge to convince water utilities.
This year’s event attracted over 200 attendees from 30 counties – a significant increase since the event started in 2011 with 20 attendees. As part of an update
on SWAN, executive director Amir Cahn announced that a beta version of a new wastewater network management tool is now available.
Utility perspectives
Speaking at the event, Michael Toh, director of water supply (network) department at Singapore water agency PUB, said: “The water sector is conservative but
this is deservedly so.”
He added: “Being inundated by data can be intimidating for a utility – how can we be sure we don’t miss anything? We need a common data platform for differ-
ent vendors so it becomes more user friendly. We also need to share experiences and talk about mistakes.”
Meanwhile, George Theo, CEO of utility Unitywater in Australia likened smart water networks to the human nervous system.
“Smart water networks are like a human body – if we have a sore knee, a message is sent to our brains. We have to ask the question of how can we turn dumb
pipes and the network around to tell us something is happening before it occurs.” He said:
“At Unitywater we are at a point where we can turn our water network into a smart network – we have a couple more dots to connect but the sewerage network
remains the poor cousin left behind by smart water developments.” The CEO said the utility is also getting interesting insights from social media. In one incident,
following heavy storm water the local media reported that the utility’s water wasn’t safe to drink. Unitywater used social media channels to quickly address
this and inform customers the water supply was safe. On the billing side, the Unitywater CEO said they managed to save AUD$1 million per year by converting
100,000 customers from paper to digital bills, at a mere cost of AUD$6,000.
Dr Tin-Lai Lee from the Taiwan Water Corporation said one of the key drivers for the adoption of smart technologies is that 40% of the utility’s workforce is set
to retire soon. As part of a water reduction plan from 2013-2020, Taiwan aims to cut leakage levels down to 14.25% by 2022, from 16.35% this year.
The utility has started pilot projects with British companies HWM Global and i20, which Dr Lee reported had “calmed down leakage”.
A new smart water leader
Following the launch of its North American Alliance, SWAN is also launching an Asia-Pacific Alliance and is looking for lead partners.
Commenting on the adoption of smart technologies in the US, Marc Bracken, chairman of SWAN North America said: “In five years the US has overtaken other
parts of the world in terms of the adoption of AMI (advanced metering infrastructure) and smart networks…North America is becoming a smart water leader.”
Will Maize, senior analyst at Bluefield Research added that the US has seen the “highest adoption level of AMI”.
He also said that Singapore and Israel had witnessed a high adoption of smart water technology, driven by water scarcity.
The digital water revolution currently taking place has led to multiple industry partnerships and acquisitions in recent months. Companies traditionally involved
in segments such as pumps are looking to diversify into the smart water space.
Last week Danish pump company Grundfos partnered with Israeli firm TaKaDu), with Xylem acquiring US smart metering company Sensus and Singapore firm
Visenti prior to that.
With new companies entering the market, such as Chinese telecommunications firm Huawei (read story), it has become an exciting space and one which is
gaining the interest of investors.
Despite this, during a panel debate on finance, it was said that only 0.25% of global venture capital is directed towards the water market.
Since its first event in 2011, the SWAN annual conference has gathered momentum, with utilities now making up 30% of members and actively participating.
Water suppliers are now talking about pilot projects, results and impacts on efficiency and leakage, rather than speculating on what could be improved.
Water may be late to the digital and smart technology table, but it now has a firm place as it looks to slowly, but surely, improve efficiencies.
Page 8

Northumbrian Water train fire-fighters to avoid pipe bursts
To help tackle burst water pipes and reduce the chances of customers experiencing discoloured water Northumbrian Water is helping to train fire-fighters
across the North- east.
The company is working with fire and rescue services across the region to help them better understand how they can reduce the chances of inadvertently
causing a burst or discolouration when they attend incidents.
Fire-fighters have been attending sessions at Northumbrian Water’s training facility, The Water Shed, in Pity Me, Durham, and a special video has been
produced to spread the learning throughout the region’s frontline crews.
When attending incidents, it is often necessary for fire-fighters to operate hydrants, which can cause fluctuations in the pressure of local water supplies.
Incorrectly doing so can cause massive spikes in water pressure that result in bursts and loss of water supply to local properties.
The training gives fire-fighters the understanding of why this happens and the knowledge of how to avoid it.
Cris Burt, trainer at Northumbrian Water, said: “In the type of high-urgency situations in which fire-fighters work there can often be a need to take action
quickly. However, there is a danger that incorrectly operating valves on the water network when shutting off a water supply can build up pressure very quickly
and cause a burst that leaves customers without water or with discoloured supply.
“We are working with fire-fighters, as well as other organisations that have operational access to hydrants and other parts of the network, to ensure we
continue to deliver the best possible standards of service to our customers.
“We are carrying out training at our centre in Pity Me, but the production of the video means we can get this important message to as many fire-fighters as
possible.”
South Staffs opts for US software firm for customer engagement
South Staffs Water has put a new strategic partnership in place with San Francisco company WaterSmart Software to engage with their end-use customers
through a digital analytics and communications platform.
South Staffs Water is implementing technologies to improve water-use efficiency while driving measurable improvements in customer satisfaction as part of a
broader program to develop and adopt innovative solutions.
Commenting on the partnership, Phil Newland, Managing Director of South Staffs Water said:
“We are excited by the use of technology to engage with our customers. Our aim is that through the WaterSmart platform, our customers will become more
actively involved in the shared challenge of how best to manage our precious water resources.”
The announcement signals international expansion for the digital water technology pioneer. Robin Gilthorpe, WaterSmart Chief Executive Officer commented:
“WaterSmart is excited to bring our award winning engagement and efficiency solutions to the UK market. South Staffs Water is an industry leader and their
embrace of innovative technology approaches in a quest for improved customer engagement is an ideal fit for the WaterSmart platform.”
WaterSmart provides households with access to easy-to-understand information via email Water Reports and a web and mobile portal.
The platform offers detailed water use data, comparative water scores, alerts and notifications, and an innovative ‘discovery’ module that allows customers to
take specific actions to better manage their water usage. The initial program will serve a pilot group with digital Water Reports and will include an additional
randomised control group in order to measure program effectiveness for South Staffs Water.
South Staffs Water (incorporating Cambridge Water) supplies drinking water to around 1.6 million people in its two areas of supply. The company does not
provide wastewater services, but bills customers on behalf of Severn Trent Water and Anglian Water.
OFWAT TAPPED IN Report in March 2017 Ofwat published a report it commissioned looking at best practice in customer engagement, including other sectors
and other countries.
Tapped ln - From passive customer to active participant is intended to help water companies identify the possibilities for them and consider what they need do
to bring customers into their thinking as active participants ahead of the business planning stage of PR19.
WaterSmart said its platform represents a best-of-breed solution that is proven to achieve the objectives of the framework for customer participation called
FACE (futures, action, community, experience) set out in the report, supporting better customer engagement as a prerequisite for improved water system
resiliency.
WaterSmart works exclusively with public and private water suppliers and is one of just 30 companies worldwide to receive the 2016 World Economic Forum
Technology Pioneers Award for their potential to “significantly impact business and society through the design, development and implementation of new
technologies and innovation.”
WaterSmart said suppliers using its cloud-based customer engagement and analytics platform have been proven to reduce costs, protect revenue, and increase
customer satisfaction by more than 25%.
Page 9

Water sector: cyber attack reporting
requirement now in force
The Water Industry (Suppliers’ Information) Direction 2017 which came into force on 1 April 2017, has included an obligation for the first time for the water
companies to report on cyber attacks.
The new Information Direction has been issued by the Drinking Water Inspectorate (DWI) to all water companies in England and Wales setting out their
obligations to provide detailed data in electronic format on a wide range of operational parameters.
The Direction also requires them to report “any significant occurrence, apprehended or otherwise of where the company has identified interference with
electronic systems caused by external interference (‘cyber attack’) that has or could impact quality or sufficiency of water.”
The requirement is included in a list of information the water companies must provide for events, incidents, emergencies etc. under a range of circumstances.
They are also required to report on any other matter that in the opinion of the supplier, is of significance and has attracted or, in the opinion of the supplier, is
likely to attract local or national publicity.
In the event of a cyber attack, the DWI expects some answers in three days. The notification must be given as soon as possible after the event or matter has
come to the supplier’s attention, by telephone; and confirmed in writing (by electronic mail) no later than 3 working days after compliance.
The Direction says the notification must also include:
• a description of the geographical area affected by the event and the site reference of any assets impacted by the event
• an assessment of its effect or likely effect on the quality or sufficiency of water supplied by the supplier;
• an estimate of the population affected and whether particularly sensitive water users such as hospitals, schools, or food manufacturers are affected;
• any information available about the cause or likely cause of the event or matter;
• particulars of the action taken or proposed to be taken to inform and protect customers and to rectify the situation, and an estimate of when supplies
are likely to be back to normal;
• a list of any persons (other than customers of the supplier) notified of the event or matter, and a copy of any notice issued to customers and to the
press about the event or matter
Depending on the category of the event, within 20 working days of the date of the notification the water companies are also required to submit an assessment
of the effectiveness of the action taken in respect of the event or matter, together with a statement of any lessons learned and of any proposals, if any, for
further action that the water supplier considers necessary or desirable in the light of the event or matter.
DWI assumes water companies’ capability to detect a cyber attack and to readily understand it how happened
Commenting in the Waterbriefing LinkedIn AMP6 Discussion Group, Sheridan Morris, Principal Consultant with PA Consulting Group, who specialises in cyber
security and risk management of OT systems and organisational data assets, said:
“DWI makes two key assumptions in setting this Direction: firstly that water companies have the capability to detect that such a cyber attack has occurred, and
secondly that companies have the capability to readily understand how such an attack took place.”
“It can take weeks of specialist investigation to understand a compromise within organisations such as banks and defence organisations who maintain a high
level of network and system security monitoring and an incident response capability.”
Deployment of cyber security measures in operational water infrastructure is “less common”
According to Morris, although a degree of such cyber security measures exist within water company corporate IT networks, their deployment in operational
water infrastructure is less common.
The supporting, but critical, presence of maintained cyber incident response plans and trained staff are also less frequent for this side of the business.
“This is reflected in the fact that cyber security across the water sector was assessed as low-to-medium by Defra in 2016. Hence the identification of cyber
incident response planning as one of six cyber security areas of focus for the sector in the recent release of Defra’s first Water Sector Cyber Security Strategy.”
Morris said.
Water companies need to ask key questions
The cyber security expert said the water companies need to ask themselves the following questions promptly.
• Does their risk register contain a scenario that encompasses a successful cyber attack upon systems that could impact supply and/or quality?
• What are their confidence levels that they could identify such a cyber attack?
• What is the depth of their defensive security and what might it detect?
• What technical measures do they currently have in place that would enable a forensic investigation into the chain of events over the preceding month,
or preceding three months?
• Do they know what these technical measures look like?
• What policy, process and people capabilities do they have in place to respond quickly and effectively once a problem is identified?
Page 10

Other data the DWI also requires the water companies to provide in electronic format includes:
For each abstraction point– its designation, its type of source water such as surface, ground or mixed, the national grid reference of its location and an estimate
of the average total daily volume (in cubic metres) of water that it supplies; the designation of each water treatment works that it serves.
For each water treatment works– its designation and the national grid reference of its location; the designation of each supply point (if applicable), service
reservoir and water supply zone that it serves.
For each service reservoir– its designation, the national grid reference of its location and its capacity; the designation of each water supply zone that it serves.
For each supply point– its designation, the national grid reference of its location and an estimate of the average daily volume (in cubic metres) of water that it
supplies;
For each water supply zone – its designation; an estimate of the number of people living within it; where a water supply zone receives a supply of water from
another water supplier, for each such supply, details of the upstream water treatment works from where the water originates; and details of all other upstream
assets associated with the original supply.
Provision of information for mapping
The water companies are also required to provide the drinking water quality regulator in electronic format with the following data to allow maps to be
produced to an appropriate scale:
• the location of each abstraction point, water treatment works, supply point and service reservoir;
• the boundaries of each water supply zone;
• each abstraction point, treatment works, supply points, service reservoir and water supply zone must also be allocated a unique name and number.
• The Direction has also been updated to make changes necessary due to the commencement of competition with respect to non-household sup-
plies and to update requests for data to reflect needs of the Inspectorate.
Royal HaskoningDHV takes lead on Rotterdam rain radar data
project
Rotterdam remains at the forefront of climate adaptation following the
engagement of a Royal HaskoningDHV-led Smart Water team. The team is
assigned to improve the accessibility of data gathered by the city’s Rain Radar,
enabling end-users such as traffic information systems and pumping stations
to response proactively to extreme weather events.
Installed on top of one of Rotterdam’s tallest buildings, the city’s Rain
Radar which measures local precipitation levels is the first of its kind in the
Netherlands and forms part of the city’s wider Climate Change Adaptation
Strategy.
A high volume of data has already been gathered by the radar but a client
consortium of the City of Rotterdam, three local water authorities and the
province of Zuid-Holland has taken the next step by engaging a team, led by
Royal HaskoningDHV and including experts from Nelen & Schuurmans and
Infoplaza to ensure data can be translated into better, more accurate
forecasting, allowing stakeholders to act proactively on these predictions.
Hanneke Schuurmans, project manager for Royal HaskoningDHV said, “Rotterdam is leading the way in the creation of climate resilient cities. We will work
in close corporation with SkyEcho and TU Delft, who are developing specific software to transform the radar signal into rainfall intensities. We will combine
this data with data from six other radars and use this to develop forecasts. As a result we will improve our current rainfall images by a factor of 100, making
forecasting 100 times more accurate.”
“These improvements will result in a wealth of applications designed to improve the resilience of city services from control of pumping stations and storm water
collection to traffic management during extreme rainfall.”
Johan Verlinde, Asset Manager Water, City of Rotterdam said: “Rotterdam is proud to be recognised as one of the world’s leading resilient cities but as climate
continues to change and our city continues to grow, we must embrace the available technology to ensure that our infrastructure and residents are better
prepared to adjust to those changes.”
Royal HaskoningDHV has extensive experience in the creation of smart water solutions having recently delivered a high profile Flash Flood Forecasting app to
the citizens of Ghana and are currently working on a Flood Information System for Parramatta Sydney (Australia). Work on the Rotterdam project started in April
and is expected to run for two years. The team expects initial work will be complete by June, allowing the system to catch the intense rainfall events that mostly
occur in the summer months.
Page 11

Opinion:
Adopting Water 4.0?
The question that I am often asked is why the Water Industry hasn’t gone futher in adopting the Smart Water Industry or Water 4.0. For the sake of this article I am
going to call them one and the same thing, those out there who distinguish between the two will be cringing but give me a few lines to explain.
The Water Industry has often been accused of acting in a somewhat glacial fashion when it comes to adopting technology and to most of the suppliers out there it
probably seems the same when it comes to the newest buzz word in the arsenal that of Water 4.0 or the “Smart Water” Industry or the Digital Industry. New things
are being developed all the time and for those in the industry who are technology biased the use of data and the Smart Water Industry seems to be somewhat of
a no brainer. We as an industry collect data and the Smart Water Industry is exploiting the data, turning it into information to allow the industry to operate more
efficiently. Its simple. However, the art of it is the art of a true professional and that is making things that are incredibly complex look simple and this is the key.
On top of this, in the industry at the moment, we have a huge amount of very clever and very intelligent things from smart water meters to instruments that are
self-diagnosing and able to control elements of the industry’s systems to Software as a Service that detect things at incredibly small amount to drones that can be
used to conduct aerial surveys to satellites which detect things from outer space. The array of innovations in instrumentation and the digital space is quite simple
awe inspiring at the moment. So why aren’t all of these things being adopted and used. There are several reasons and the rest of this opinion piece is going to be
dedicated to outlining some of the reasons why all of these great technological innovations aren’t being adopted at the fast pace that would surely make that next
bit of efficiency savings.
Understanding the technology
There is a huge array of technology out there promising to do a wide variety of things and some of it is aligned with what the Water Companies do and some of
it doesn’t and yet more is technology that has been developed to satisfy a need that has been anticipated will happen but not yet. The really difficult thing to do
is understand the technology, its strengths and its weaknesses and its potential application and of course being able to find ways of testing things when time is
not necessarily available. Of course when it is relatively small things then this can be relatively easy. Over the past few years I have trialled a few instruments with
relative ease and worked with the suppliers and with some the first purchase has come relatively quickly as the applications have come up and with others the first
sale is yet to be made.
It has often been said of this industry is that it necessary to trial technology for extended periods of time and in each and every company but of course the real key is
actually understanding where the technology will work for instrumentation. Of course for larger, system wide innovations then the complexity of things increases a
huge amount more. This is particularly the case of control systems based upon treatment works and this possibly where the key barrier to adopting “Smart” Control
Systems becomes a huge barrier.
The main problem is understanding what the innovation is and what it actually does and what the benefit will be and lastly why it can’t be done in house with an
instrument or two and somebody programming a PLC. Of course the answer in some of these innovations is that it can be done in-house with some instruments
and someone programming a PLC but the essence of the innovation will be lost and the full savings of what purchasing the system from a supplier lost. The point
just missed. This is a problem of understanding that buying technology actually is something that is almost equal to a more traditionally based capital scheme and
the delivery of these innovation is best dealt with in this sort of field as an alternative to pouring concrete with efficiencies in the capital delivery readily there to be
realised. This of course would rely on the technology aligning itself with the need of the capital scheme....a more efficient way of operating the treatment works en-
abling its capacity so that a “Smart Solution” could realise extra capacity in the treatment works to enable more major investment to be deferred a few more years.
Understanding the benefits
Where do the benefits lie? Why should I invest in this particular widget? What is it going to do for the company? These are all questions that anyone who has stood
in front of their manager or an investment board will face. The questions are of course very fair and the line you will often face is “If you were spending your own
money would you buy it?” It can be quite a terrifying thing standing in a room in front of a board of people and explaining why this particular widget should be taken
and adopted by the business and for most of the technologies that are out there the benefits aren’t always fully understood. If you are lucky then you have a wealth
of case studies to fall back on and can explain “Well this particular thing will address this particular problem and the benefits that we will see are going to be this
and that and that. Of course if all of the benefits aren’t understood then this process becomes incredibly difficult.
Imagine the situation - you are standing in a room of 20 people who have asked for a particular situation to be resolved and you have a technological solution that
will do everything that you want and importantly more. You present and are asked “What are the benefits and how sure of them are you?” and “What is the Return
on the Investment?” and “Where has this been delivered before?” If all of the answers are there then everything is absolutely fine, if the business case is there and
the Return on the Investment is right then everything is absolutely fine however if it isn’t and all of the benefits and all of the savings are not understood then stand-
ing in front of the 20 people in a room becomes a very uncomfortable place to be. Return to the case of “If you were spending your own money would you buy it?”
You are asking for a leap of faith from a number of people and although not impossible the argument becomes alot more difficult
Direction and timing
For some companies it is simply not the right time for a particular technology be it an instrument or an entire system. A good example of this was one of the
Water Companies in the UK who installed metering across the whole company, a fantastic achievement which helped the company to understand exactly what was
going on. This was a small number of years before the big “Smart Meter” roll-out across the industry and of course they are now in the situation where reinstalling
thousands of relatively new meters with Smart Meters does not represent a good business case. Is this the right thing to do? Absolutely and for this particular
company it simply not the right time to look at the absolute newest developments. Its the equivalent of buying a new car just after you’ve bought a car just because
its got the newest features that would provide a benefit but not a huge one over what you’ve already bought. The Water Industry when it puts something in tends
to do it for a relatively long while. This is a problem of timing.
Page 12

The other potential reason is direction. Each company is going to have some challenges which are the same as all of the others, efficiency of operation is always
going to be one. How is electrical consumption going to be decreased? How is power production going to be increased? How are we going to decrease the
amount of non-revenue water? How are we going to decrease flooding incidents? These are all questions that go around every water company in the globe
virtually? But of course some of these questions are different - How are we going to meet the challenges of making all of our beaches are of an excellent stand-
ard ( of course not all water companies have beaches to worry about) and so a company without beaches in their catchment areas are going to be less worried
about UV disinfection. So for some companies the drivers and thus the direction is going to be completely different from another.
Things have already been adopted
Of course there are situations where things have already been adopted and things have already been done some in a good way and some in a way that maybe
aren’t as good as the latest widget but for the moment at least, good enough. These are the situations which have succeeded, where technology and the Smart
Water Industry are starting to be adopted. The data has been integrated and the information transformed to a point where it is providing intelligence within
the business. The most recent way of working here is at Spernal in Severn Trent Water in the UK where all of the instruments and their data have been brought
together to pride tangible benefits from the information that has been gathered and the benefits are understood and the investment is starting to see returns
in a number of different ways.
Discussion
So how are we going to realise a “Smart Water” Industry? The problems outlined so far are all inclusive in why things haven’t necessarily been adopted and
of course when they have. The main reasons are the fact that the benefits aren’t understood or a particular technology isn’t right for a particular company
at a particular time or actually the technology just isn’t really understood or isn’t the right fit for the particular company at this particular time. Where wa-
ter companies have adopted a particular approach it has usually been because of a particular need or a particular direction has been decided upon
when the technology has been seen.
Whatever you call it be it Water 4.0, the Smart Water Industry or the Digital Industry there are huge benefits from taking this approach. For those companies
that have adopted the approach there have been some amazing case studies of the benefits that have been realised. The problem of course is that these case
studies have not always been widely spread or the benefits acknowledged but not particularly understood. The challenge for the industry as a whole be it com-
pany or supply chain is to understand the benefits of the direction, the benefits of the approach and share them so that the benefits are understood so that the
business case answers the question so that the person standing in front of 20 people can answer an emphatic yes when the question of “ if you were spending
your money, would you buy it?”
Cable management system provides solution for Severn Trent grit
A new cable management system has proved the key to the more effective dredging of grit at a sewage treatment works operated by Severn Trent. When
Severn Trent Water needed to replace the cable management system on its grit tank at Coalport Sewage Treatment Works (STW), the company didn’t just want
to replace like for like. Although the old system had been in service for years, it had several flaws, so this was an opportunity to completely redesign and improve
the whole cable management system.
A grit tank is the first filter in the treatment of raw sewage, part of the primary treatment process. Essentially, the tank, which is 24 metres long, slows down the
flow of water so that the ‘grit’, which can be anything from sand, pebbles and stones, can settle to bottom. Across the tank is a bridge, which slowly moves up
and down its length dredging up the grit. Its removal is particularly important, since it can otherwise cause excessive wear and tear on pumps and other plant
equipment during the secondary treatment process.
The bridge is driven by an electric motor with the electrical functions, such as controls, I/O and sensors, running alongside. The original system was worn out
and needed replacing with something robust and reliable.
A well-known specialist in water and wastewater treatment work, within the construction and civil engineering industry, was contracted by Severn Trent Water
to provide a replacement solution for the bridge. The company’s experience spanned across the full spectrum of capital works – from source to tap and sink to
river. Regarding power provision for the bridge, the contractor approached igus, the motion plastics expert, for advice.
There are various cable management options, with each one having its merits and flaws. Festooning the cables along the tank was a popular solution in the past
– though these systems are prone to failure in adverse weather and the hanging cables can snag, look untidy and are rarely used these days. Traditional energy
chains are a good, commonly used solution, though as open systems they are also at risk of damage over time. A cable reeling drum is another obvious choice,
since it is neat and tidy. However, over time, the spring in the small cable reeling drums and the larger ones, which have a clutch and motor, tend to wear out.
In addition, as the drum carries only one cable, a custom hybrid cable is required to carry all the services, with an accompanying high price tag.
igus provided a full turnkey cable management system for the bridge. Completely enclosed and thus insensitive to dirt, dust and humidity, as well as harsh
environmental conditions, “basic flizz” is particularly suitable for automated applications. The compact system routes energy, data and media for travels of up to
120m. At the heart of the system is an energy chain that guides and protects moving media and control cables within a metal guiding channel. The latter ensures
a compact and easy to attach containment which protects the e-chain from debris such as branches or ice build-up.
“igus supported the contractor on this project right from the start,” says Mark Smith, Projects & Installations Manager at igus. “We worked closely with its
engineers and project managers throughout every aspect to get a complete, reliable solution. The basic flizz cable management system is modular in design
and thus easy to install. It’s fully enclosed and so protected from the elements and its polymer e-chain enclosed design make it robust and maintenance free.”
During the project, igus collaborated closely with the contractor and took full control of the cable management replacement project.
Page 13

Article:
Determination of Flow Rates in
part-filled Applications using the
Radar Method
Introduction
The radar measurement method plays an increasingly important role in the water and wastewater field. This is particularly reflected by the “Metering outside
of the medium” trend. Flow measurement using radar which enables contactless measurements thus becomes a major focal point. It features a wide range of
applications and hence is useful as permanent measurement system for many applications with part filled pipes or canals in the water and wastewater field.
Flow Rate Determination
The determination of flow rates is indispensable for many processes when it comes to monitor water or wastewater volumes. In order to ensure continu-
ous flow determination, however, a measurement system is required which enables optimum velocity detection for the according application. The radar
measurement method allows contactless flow velocity metering. Therefore it is ideal for applications with strong sedimentation on the channel bottom or if
sensors cannot be installed on the channel bottom or within the medium due to several reasons. In contrast to other measurement systems radar metering
entails the advantage that it is largely independent from the properties of the measurement medium such as conductivity, density, temperature or viscosity.
Moreover the microwave-based method stands out from the crowd of other flow measurement methods due to low maintenance and easy installation.
Measurement Principle
Radar sensors are installed outside of or above the measurement medium. The
radar sensor sends out a signal with a certain frequency. The signal is reflected
as soon as it impinges on the water surface. A frequency shift is induced once the
signal is reflected from the water surface. The reflected signal is detected by the
radar sensor and will be evaluated by using the Doppler principle.
Image: Schematic drawing: Radar measurement principle
The precondition for the radar method is wave formation on the water surface. The
sensor measures the movement of the waves and hence the surface velocity of
the water. On the water surface a single velocity is measured selectively. With the
aid of the hydraulic COSP model developed by NIVUS it is possible to compute the
average flow velocity from the selective single velocity. The flow level is measured
by utilising an extra level sensor which enables to determine the wetted area A.
Flow Q is calculated from the average velocity ¯v and the wetted area A as follows:
Q=¯v ×A
Q = Flow rate
¯v = Average velocity
A = Wetted area
Formula 1: General flow rate calculation
Radar Technologies
A distinction is made between pulse radar units and continuous wave radar units. Pulse radar units emit high-frequency impulse signals at high power. Once
reflected, the radar sensor receives the signal as echo. New signals will not be transmitted before an echo has been received. Continuous-wave radar units
(abbreviation: CW radar units) transmit continuous signals. Reflected signals are hence received permanently which permits to permanently measure velocities
e.g. in the water and wastewater field. Utilising the radar technology NIVUS rely on the latter method for flow measurement.
Radar Meter System
The standard radar metering system comprises a radar flow velocity sensor (optionally with Ex zone 1 approval), a level sensor and the new NivuFlow 550
transmitter. Both sensors provide the measured data for the transmitter which in turn computes the flow Q by considering hydraulic models.
Installation and system set-up can be carried out quick and easy since all measurement place parameters can be set directly on the transmitter. Extra software
or hardware are not required.
In a WWTP inlet sewer flow volume as well as flow velocity were to be determined and logged. The measurement serves as control measurement to avoid
flooding the treatment plant. The customer demanded a contactless low-maintenance system due to partially high dirt loads and thus sedimentation were
expected on the channel bottom. Due to this installing e. g. water-ultrasonic sensors on the channel bottom was not desired. A radar meter was the most
suitable measurement system for this measurement site since all requirements were met: an easy-to-install contactless measurement system.
Page 14
Schematic drawing: Radar measurement principle

Application example WWTP inlet sewer
Hybrid Flow Measurement
Apart from pure radar meter systems, NIVUS is the only provider to offer a hybrid measurement system for flow measurement. This hybrid system represents
an extension of the radar measurement system. Besides flow velocity detection using radar the flow velocity is additionally detected by using ultrasonic cross
correlation. The measurement system is therefore equipped with two flow velocity sensors, one level sensor and the NivuFlow 7550 hybrid transmitter.
Photos: Hybrid measurement system: v-sensor 1 OFR radar sensor, level sensor i-Sensor, v-sensor 2 POA sensor, NivuFlow 7550 hybrid transmitter
The transmitter combines or completes the measured flow velocities obtaining the average flow velocity. Depending on the sensor installation positions and
the filling level there are two basic applications for hybrid meter system: hybrid metering as extended measurement range e. g. during flood conditions and
hybrid metering as redundant measurement to increase accuracy.
Extended Measurement Range: Flood Sensor
Standard discharge measurement situation:
The ultrasonic wedge sensor is fastened on the pipe ceiling. In this system configuration
normally only the radar sensor measures the flow velocity.
High level measurement situation:
The ultrasonic sensor which is installed slightly out of the channel crest begins to meas-
ure shortly before the flood situation is reached depending on the installation point. In
this case, the ultrasonic sensor as well as the radar sensor measure parallel. The example
shown here (see below) has a very small measurement range since the ultrasonic sensor is
fastened to the ceiling and begins to measure only shortly before the dead zone is reached.
Based on the local flow velocities detected by the ultrasonic sensor the hydraulic model can
be optimised for the entire measurement situation.
Flood measurement situation:
Measuring with the radar sensor is not possible any more once the sensor’s dead zone is
reached. From this point on the ultrasonic sensor exclusively takes over the measurement
task.
A reliable measurement is guaranteed over the entire measurement range since the level
during such situations is measured using the pressure cell of the ultrasonic sensor.
Complete radar measurement system: OFR radar sensor, level sensor type i-Series (left) and NivuFlow 550 transmitter
Hybrid measurement system; Standard discharge measurement situation
Hybrid measurement flood condition
Page 15

Redundant Measurement for increased Accuracy
In this approach to hybrid measurement the ultrasonic sensor is installed below the minimum
filling level. Parallel to radar metering a redundant flow velocity measurement using ultrasound
is therefore carried out constantly. The ultrasonic cross correlation sensor detects local velocities
in up to 16 layers. In combination with the flow velocities determined by the radar sensor it is
possible to create an accurate hydraulic model of the measurement situation. Based on this model
the average flow velocity and hence the flow rates can be determined very accurately.
Summary
Flow metering using radar systems is becoming increasingly popular in the past years. Radar
measurement systems stand out for a wide range of uses in a large number of part filled
applications. Due to contactless measurement and the ease of maintenance radar metering is
particularly suitable for applications featuring high dirt loads or sedimentation even if it is not
possible to install sensors within the medium. The use of radar technology for flow measurement
is completed through the options provided by hybrid measurement systems thanks to increasing
the accuracy or extending the measurement.
Literature
Technical documents NIVUS GmbH, Eppingen (2017)
Internet
http://www.radartutorial.eu/02.basics/Dauerstrichradarger%C3%A4te.de.html [called up on 17.03.2017]
http://www.radartutorial.eu/02.basics/Impulsradar.de.html [called up on 17.03.2017]
Redundant flow metering
About the Author
Mathias Stratyla is a product manager at the specialist flow monitoring company Nivus, who are a developer, manufacturer and
supplier of instrumentation for the water industry. For more than 45 years NIVUS works in the field of flow measurements and
is one of the worldwide leading companies in this sector.
The product portfolio, among other devices, includes units for flow measurement, flow velocity detection, level measurement,
pressure measurement and water quality measurement. Moreover the product range comprises software for recording, logging
and evaluation of data. The range of products is completed by an extensive process control system. One of the NIVUS main areas
is flow measurement as well as the various flow meters.
Not only development and production of devices benefit from company know-how and experience, but also services such as
the implementation of complete measurement campaigns. Installation and initial start-up of flow instruments and other NIVUS
products as well as competent support on how to operate our pressure, level and flow meters are more parts of our portfolio.
Anglian Water extends use thermal imaging drones for leak
detection
Anglian Water is extending its use of thermal imaging drones to detect leaking water pipes – the utility’s performance on leakage is already around half the
national average. The new technology has already been used to successfully identify leaks in the rural villages in Norfolk, and the company plans to trial the new
technology more over the coming months. The drones have already saved Anglian Water time and money by finding hard-to-spot leaks.
The sensor and camera on the drone can identify differences in soil temperature which could be caused by water escaping from the pipe. The differences are then
investigated further by a leakage technician on-site, rather than needing to be analysed back in the office. With nearly 40,000 kilometres of water pipes, much
of it in rural and remote areas, Anglian Water hopes the aerial technology will help reduce the cost and time taken to find a leak and pinpoint its location more
precisely by spotting changes in soil temperature near the water pipes.
Paul Valleley, Director of Water Services for Anglian Water said the company is determined to keep reducing leaks, commented:
“Anglian Water is bucking the trend. We’ve cut leakage every year since privatisation in 1989 and our leakage is at record low levels - around half the national
average. We have set ourselves much tougher targets than those set by our regulator, and beaten them for three years running.”
“The East of England is a dry region and we want to do as much as possible to conserve water. Addressing the challenge of leakage is one of the reasons we can
be confident that there won’t be a hosepipe ban in the Anglian Water region this summer.”
“Last year we achieved our lowest ever level of leakage beating the target Ofwat set us, and we have ambitious targets to do even more. We’ve launched a £60m
war on leakage to continue driving levels down even further between now and the end of the decade.”
Over the last few years the water company has recruited a 300-strong team focussed purely on leakage. Anglian has also invested in state-of-the-art technology -
innovative pressure management schemes are dramatically reducing bursts and leak Technologies being used by the Intensive Leakage Teams include the thermal
imaging drones and specialist robots
Page 16

Article:
Evaluation of a Solid-State
Reference Electrode Junction Material
for Ion-Selective Electrodes
An often-neglected consideration when choosing an ion selective electrode (ISE) system is that of a suitable reference electrode. Indeed, recent extensive
reviews cite only 12 articles devoted to reference electrode considerations in potentiometric analyses [ 1,2] for the period 1988-1992. Conventional calomel
and Ag/AgCl electrodes with free flow (capillary) or ceramic junctions are suitable for general applications, but for certain important applications such as
measurement of pH in low ionic strength water or electrochemical measurements at high temperatures or pressures, the characteristics of these electrodes
may not be suitable.
The fundamental consideration for a reference electrode is that it provides a stable junction potential. The maintenance of this potential is probably the factor
that causes most difficulty in potentiometric measurements. In potentiometry, one monitors the cell potential (Ecell
), which includes a contribution from the
reference electrode junction potential (Efn
), the reference electrode half cell potential (Eref
), and the ISE .Potential (EISE
). On transferring between solutions, the
change in cell potential (ΔEcell
) is given by
potential in solution 1: Ecell(1)
= EISE(I)
- Eref(l)
+ Efm(I)
potential in solution 2: Ecell(2) = EISE(2) - Eref(2)
+ Ejn(2)
change in cell potential: ΔEce11
= Ecell(2)
- Ecell(2)
Hence, the conditions Ejn(1)
= Ejn(2)
and Eref(1)
= Eref(2)
must hold if the overall change in cell potential is to be determined solely. by the ISE and, thus, enable deductions regarding the concentration or activity of the
primary ion in unknown solutions to be made via the Nernst equation. The reference half-cell potential is usually unaffected by transferring from solution to
solution, as it is not in direct contact with the sample solutions. However, maintenance of stable junction potentials can be a real problem in many applications
and is unfortunately often overlooked as a major source of error in potentiometric measurements.
The role of the junction is to provide an electronically conducting pathway between the ISE and the reference half-cell via ion transfer from the salt bridge
solution into the sample, but which does not allow bulk mixing of the bridge electrolyte and the sample solution. Commercial electrodes incorporate a
porous ceramic frit, fiber wick, microcapillary, or ground sleeve to enable the salt bridge ions to diffuse slowly into the sample. In all of these junction designs,
prevention of bulk mixing of salt bridge and sample ions is achieved through the use of very small areas of contact between the two solutions. For high-
precision pH work, a renewable liquid junction, as in a free-diffusion junction (microcapillary), is recommended [3 ]. However, this type of junction is obviously
unsuitable for measurements at high pressure (such as in chemical or bioreactors) as the sample would be forced into the reference electrode body and hence
cause shifts in the reference half-cell potential. In addition, frits may experience residual memory effects from buffer solutions, which could give rise to errors
[ 4]. For pure water applications, it has been recommended that the porosity of the junction be increased by reducing the length of the ceramic frit to decrease
junction potentials [5]. In many situations, the reference electrode junction potential can become unstable, e.g., due to clogging or poisoning (in hostile
industrial environments), dilution of the salt bridge (in pure waters), or precipitation of protein (in clinical samples) [6]. Obviously, when a very restricted
diffusion path is used, as in almost all commercially available reference electrode junction designs, the susceptibility to clogging is very high, with
consequent adverse affects on the stability of the liquid junction potential and the accuracy /precision of the electrochemical measurements. The solution to
these problems lies in the development of junction materials with the following characteristics:
• low electrical resistance;
• low leakage rate of ions into sample;
• no permeability of ions from sample to internal electrode reference element (e.g., Ag/AgCl wire);
• capability of using large-area junctions;
• resistance to pressure and/or temperature effects; and
• resistance to contamination from troublesome samples (e.g., in clinical, environmental, or food analysis).
From these considerations, what clearly is needed is a solid-state material capable of forming a stable junction potential in a wide variety of media with minimal
contamination of either the junction or the sample during measurements.
In routine applications, KCl is normally used as the bridge electrolyte as the almost-equitransferrent ions minimize the magnitude of the junction potential.
However, a number of other electrolytes such as lithium acetate or lithium sulphate can be substituted for KCl in situations where leakage of these ions into
the sample is undesirable [7]. For this reason, KC! was used as the dopant salt in the Refex polymer and in the internal reference half-cell in all the studies
subsequently described.
Experimental
Design and Fabrication of Reference Electrodes with Refex ]unctions
Samples of the KCl/vinyl ester mixture were provided by Amagruss Electrodes Ltd., Castlebar, Co. Mayo, Ireland, and used as received. The samples obtained
were 50% m/m KCl/vinylester resin in composition. Prior to polymerization, the material is not particularly viscous and can be preformed in molds or spun into
tubes. During the curing process (24 hours typically after addition of an initiator, MEKP (2-butanone peroxide]), it becomes hard and can be machined or turned
successfully even though it is quite brittle. In this research, two types of junction design were investigated.
Page 17

Type A (standalone reference electrode). In this design, the KCl/vinyl ester mixture was poured into a glass form with an external diameter of 10 mm. An Ag/
AgCl half-cell, with a filling solution of 2.8 M KC!, was then placed in this mixture and positioned as close to the edge of the form as possible. The Refex material
was allowed to cure overnight, removed from the glass form, and fixed into an epoxy body so that 12 mm of the Refex protruded (Figure 1).
Type B (combination pH electrode). An internal pH combination electrode with four frit-restricted liquid junctions (Figure 2A) was positioned inside an epoxy
body with four windows by means of an “O” ring so that the four ceramic frits were opposite the windows in the body. These windows and the pH membrane
were then protected with parafilm. The body of the electrode was then inverted and filled with the Refex material. This was allowed to cure overnight to give
a double-junction (DJ) design, with a Refex junction in direct contact with each of the ceramic frits (Figure 2B). A second O ring was used to seal the Refex and
to help keep the glass electrode in position.
Precision and Stability Studies
Measurements were made on a deionized water that had a base conductivity of 1.5 to 2.0 μS pH and mV measurements were made using a Jenway 3040
ion-analyzer and a commercially available pH glass electrode (Amagruss Ltd.). Commercially available Orion DJ Ag/ Agel, saturated calomel electrodes (SCE) and
Ag/ AgCl disk electrodes were used versus the Refex electrode for general stability studies. All materials were of reagent grade and used as received.
pH measurements in deionized water were taken in both static and slowly stirred solutions. Buffers conforming to DIN 19267 standard at pH 7.00 and 4.01
(Merck, Darmstadt, Germany) were used to calibrate the electrodes. pH measurements in pure water were taken at 30 second intervals up to 10 minutes. This
procedure was repeated 10 times, and the average and standard deviation were calculated in each case. All measurements were made at 25 ± 0.1°C.
Linearity of response over the pH range 2.0 to 11.9 was examined using a stand-alone (type A) Refex electrode and a conventional pH glass combination
electrode (innovative Sensors Inc.). Phosphate buffer solutions were made up as described by Christian [8] in 0.1M NaCl All potentiometric measurements were
made at 25 ± 0.1°C.
Electrolyte Leakage Studies
Leakage of electrolyte from the reference electrode junctions was assessed by
1. Measuring the increase in conductivity of water in which the electrodes were immersed using a Jenway 3070 conductivity meter. This was monitored
according to the following procedure:
The Refex electrodes were soaked in deionized water for 2 to 3 days to remove any KCl that may have built up on the outer surface: 100 mL of the ·pure water
was placed in a polycarbonate bottle, and the conductivity of the water was measured prior to insertion of the electrodes. The bottle was then sealed with
parafilm to prevent any particulate contamination. During measurements, the electrode was removed, the water was stirred for 1 minute, the conductivity
probe was placed in the water, and the conductivity was measured after 1 minute. The electrode was then replaced in the water and resealed until the next
measurement. The leakage from the electrodes was monitored over a period of 5 days.
2. Measuring the increase of concentration of potassium ions in the water in which the electrodes were immersed, using a Dionex Ion-Chromatography system
(Ion-Pac CS3 column, mobile phase 25 m.’11 HCL/0.2; mM DAP-HCl (DL-diaminopropionic monohydrochloride), flow rate 1.5 mL/min, and 100 mM TBAOH
(Tetrabutylammonium hydroxide) as the regenerant. The same procedure as described earlier was used except that samples Q200 μL) of the deionized water
were removed for analysis by the ion-chromatograph at regular intervals over a period of 4 days.
Electrochemical Impedance Measurements
In this study, the impedance spectrum of an electrode with an undoped (inactive) Refex type~ A junction (i.e., does not contain any KCl) was compared to that of
an identical electrode with the normal doped (active) Refex junction. The measurements were performed in 0.1 M aqueous NaBF4 at room temperature using a
HP-9816 computer-controlled S-5720B frequency response analyzer and a NF-2000 potentiostat/galvanostat with a GPIB interface (NF Circuit Design Block Co.
Ltd., Japan). The typical amplitude of the sinusoidal voltage signal used was 100 and 200 mV.
Figure 1: Schematic diagram of RepHex type A standalone
reference electrode.
Figure 2: Schematic of RepHex type B combination pH electrode showing (A) the internal pH combination electrode
and (B) the outer RepHex body with active RepHex windows in contact with the ceramic plugs from the combination
electrode salt bridge.
Page 18

Results & Discussions
pH Measurements in Deionized Water
The results obtained with the Refex A and conventional ceramic frit DJ reference electrodes are shown in Figure 3 for measurements of pH in deionized water
(the same glass electrode was used for both sets of measurements), which was stirred slowly during the experiment. From these results, it is clear that the
Refex junction gave much more precise results over the entire 10 minute measurement period compared to the ceramic frit electrode.
Even after 10 minutes, the standard deviation of results obtained with the ceramic frit junction was approximately 0.18 pH. Furthermore, the mean value did
not stabilize for around 6 minutes. In contrast, the cell incorporating a Refex junction gave almost instantaneously stable results with much better precision
(standard deviation 0.07 pH after 0.5 minutes, decreasing to 0.035 pH after 10 minutes). Note that the range of pH values obtained in both studies (pH 5.5 to
6.0) is typical for deionized water in equilibrium with atmospheric C02 [9].
Stability in Buffer Solutions
The results obtained from seven studies are summarized in Table 1 and in Figure 4. Table 1 illustrates the performance of the Refex type A electrode in
three commonly used buffer systems as the background concentration of NaCl is gradually raised. In these experiments, either a calomel (SCE) or Ag/AgCl
reference electrode was used to check the stability of the Refex signal. In every case, the overall cell potential showed no change to within the limits of
accuracy of the meter 0.1 mV), except for the boric acid buffer (pH 9.2) where the signal versus the SCE changed b~ around -0.3 mV during the addition of the
NaCl. Furthermore, on raising the pH from 5 to 9.2, a change in overall cell potential of around +2.0 mV is obtained vs. SCE, and around -2.0 mV vs. Ag/ AgCl
reference electrode. These results clearly demonstrate that the Refex electrode can provide a very stable reference potential for pH measurements in these
buffers, which is independent of variations in NaCl concentration up to 0.016 M. This is relatively small in comparison to the change of around 240 mV, which
would be obtained theoretically with a pH glass electrode over the same range, and the error at <l.0% is entirely acceptable for these types of potentiometric
measurements.
This assumes the worst-case situation, i.e., that all the variation in the cell potential arises at the Refex
junction. However, it is unclear at this stage whether the error is arising at the Refex junction or at the
liquid junctions of the conventional electrodes (or both). It should also be noted that replicate meas-
urements performed with an undoped Refex type A electrode gave very unstable signals in ~very case,
which demonstrates the fundamental role played by the KCl in providing the very attractive properties of the doped Refex. Impedance measurements (see
subsequent discussion) confirm that the high salt loading of the Refex material imparts the desirable properties, and in the absence of the salt, a classic
Figure 3: Comparison of RepHex type B and conventional combination pH electrode for pH determinations in stirred deionized water showing the mean and standard deviation for
measurements taken at 30 s intervals up to 10 min (n = 10)
Table 1: Stability Tests for Refex Type A Stand-Alone Reference Electrode in Various pH Buffers during Addition of
Aliquots of 1.0 M NaCl to 50 ml of Buffer . .All Readings are in mV, Taken 1 Min and 2 Min after Immersion of the
Electrodes in the Sample or Addition of the NaCl.
Figure 4: Response of Ag/AgCl disk electrode versus
Refex reference electrode in 50 ml 0.1 M pH 5 acetate buffer
to additions of 50, 100, 200, 400, and 800 μL of 1.0 M NaCl.
Measurements taken 1 and 2 min after each addition; S =
53.68 mV /decade Cl-, r2 = 0.9999 (after 1 min), and S = 54.147
mV/decade c1-, r2 = 1.0000 (after 2 min).
Page 19

electrical “blocked” interface of very high resistance is obtained. · ‘
Figure 4 shows the response obtained in an identical experiment performed with a Ag/ AgCl disk indicator electrode and the same Refex type A reference
electrode as aliquots of 1.0 M NaCl (50, 100, 200, 400, and 800 μL) were added to 50 mL 0.1 M pH 5.0 acetate buffer. Measurements were made at 1 and 2
minutes after the additions. The two curves are virtually superimposable, and the log [Cl] versus potential curves were very linear (S = 53.68 mV /decade Cl, r2
= 0.9999 (after 1 minute), and S = 54.147 mV /decade Cl, r2
= 1.0000 (after 2 minutes)). Clearly, these results demonstrate that the Refex electrode is capable
of providing a very stable junction for pH and ion-selective measurements and is unaffected by variations in background electrolytes such as NaCl.
pH Linearity Studies
In order to further test the Refex electrode, its performance was examined over the pH range 2.0 to 11.9 in a constant background of 0.1 M NaCl. Three replicate
sets of potential versus pH readings were taken for a conventional pH glass combination electrode with an integral Ag/ AgCl reference half-cell (fiber wick
junction) over the pH range investigated, and the mean and standard deviation of the results were calculated. The reference half-cell was then disconnected
from the meter and the experiment repeated using a stand-alone Refex (type A) electrode as reference for the same glass electrode. The results (Table 2 and
Figure 5) show almost identical behaviour over the entire range. Clearly, there is a curvature at pH values <4.0, which is independent of the reference elec-
trode used, and is reproduced over the six experimental runs. The standard deviations obtained are smaller in almost every case (except pH 11.9) with the
Refex reference electrode, while with both reference half-cells, the precision appears to deteriorate toward high pH values. The mean slope obtained (pH
6 to pH 11.9) is 58.89 mV /pH with the Refex electrode compared to 58.54 mV /pH with the combination cell. Once again, these data confirm that Refex-based
reference
electrodes can be used with confidence for pH measurements in place of conventional reference electrodes.
Measurements without Liquid function
The previous experiment was repeated using a Ag/ AgCl wire (without liquid junction) versus Refex
electrode type A Hence, the only junction is that of the Refex electrode, and as the chloride ion
activity is kept constant, in theory, the Ag/ AgCl wire should maintain a constant
potential against which variations in the Refex electrode junction potential can
be detected. The results for three replicate experiments are presented in Table 3.
These results show that the Refex junction again behaves very similarly to
the calomel/ceramic junction electrode. In both cases, the junction potential chang-
es by around -5.0 mV, assuming the variation to arise solely at the junction, with simi-
lar standard deviations (most of which are substantially less than 1.0 mV). Once again,
this strongly suggests that the Refex junction will behave similarly to conventional
reference electrode junctions in routine pH measurements.
Leakage Studies
The results of the conductivity studies are presented in Figure 6 for five reference
electrodes, two with type A active Refex junctions (Refex Al and Refex A2), two double
junction Ag/ AgCl reference electrodes with ceramic frit junctions (DJl and DJ2), and
one combined glass electrode with the Refex B type junction (Refex B). The
increase in conductivity brought about by leakage of KCl from the reference
electrode junction into deionized water samples was greatest with the ceramic frit electrodes. This is surprising, considering the much greater junction area
(see Table 4) and heavy KC! loading of the Refex electrodes. The lower leakage rate obtained with the Refex B to Refex A electrode is predictable from the
smaller junction area.
These trends were confirmed by monitoring the increase in K+ in the storage water using ion chromatography. Figure 7 shows results obtained with Refex A,
Refex B, and ceramic frit junctions (DJ). Once again, the leakage of K+ is greatest with the ceramic frit, and the general trends in the curves obtained are very
similar to those obtained with the conductivity measurements, confirming that it is leakage of KC! from the Refex junction that is causing the observed increase
Table 2: Comparison of a Glass Combination Electrode Performance with that of the Same Glass-Electrode Half-Cell
Versus a Refex-Type A Reference Electrode
Figure 5: Response curves obtained with a combination pH
electrode () and a Ref ex type A reference electrode (□) in buffer
solutions (pH 2.0 to 11.9, background 0.1 M NaCl). After obtaining
the combination electrode results, the in-built Ag/AgCl reference
electrode was disconnected from the pH meter and replaced with
the Refex electrode.
Table 3: Mean and Standard Deviations (n = 3) of Potentials of a Refex Type A
Reference Electrode and a Calomel Reference Electrode (Ceramic Frit Junction)
Measured over the pH Range 2.0 to 11.9 in a Constant Background of 0.1 M NaCl vs.
Ag/ AgCl Wire Electrode (without Liquid Junction)
Page 20

in conductivity. When the leakage rates are normalized for junction area, the rate of K+ leakage with Refex A and Refex B junctions are almost the same at
around 6.0 x 10-8 mol/ h/mm2
. In contrast, leakage through the frit junction is almost three orders of magnitude higher at 2.67 x 10-5 mol/h/mm2
(see Table
4), which is typical for junctions of this type [10,11]. Clearly, the release of KCl into sample solutions is extremely slow compared to the ceramic frit junction
when normalized in terms of junction area. This is a very surprising result, in view of the heavy loading of KCl in the Refex resin and the relatively large active
area over which leakage may occur. This situation offers many potential advantages:
• as KCl is released from the outer boundary of the Refex junction, there remains a huge reservoir of KCl within the resin matrix. Hence, release will occur in
a consistent, controlled manner over extended periods of time leading to stable. reproducible junction potentials:
• stability is further enhanced by the ability to use large junction areas compared to other designs based on diffusion of KC! from an internal bridge
solution that is restricted by means of a narrow capillary. a ceramic frit, or a fiber wick. Hence, clogging, coating, or blockage can be expected to be much
less problematic with Refex junctions:
• reduction of Refex junction areas and salt loading can be expected to produce much lower leakage rates than those observed in this study, although this
may reduce the junction potential stability; and
• the liquid nature of the salt-loaded resin before curing offers very flexible handling during fabrication and raises the prospect of possible applications in
more specialized designs, such as a reference element in solid-state sensor manufacturing (e.g., in ISFETs or hybrid devices).
Impedance Studies
The impedance spectra for the undoped (inactive) and doped (active) electrodes with Refex type A junctions are shown in Figures 8 and 9, respectively,
together with equivalent circuits for each. The results (Figure SA) show a blocked interface effect on the inactive Refex junction as demonstrated by the
extremely high impedance at low frequencies, and an unblocked Faradaic impedance with the active Refex junction (Figure 9A). The almost vertical line to the
right of the semicircle in Figure SA is typical of a blocked interface, with no fixed DC resistance and no DC current.
The equivalent circuit for the inactive Refex junction is given in Figure SB. This shows a double-layer capacitance (Cd) in series with the bulk resistance and
capacitance (Rm and Cm), which gives rise to the very high impedance at low frequencies.
In contrast, rhe impedance spectrum for the active Refex junction (Figure 9A) shows two adjacent semicircles characteristic of an unblocked interface [12],
reflecting two relaxation processes with time constants (τ’ and τ’) given by
τ’ = Rm
Cm
= 1 = 0.03 ms
ω’
and
Figure 6: Changes in conductivity in deionized water solutions in contact with RepHex type A
electrodes (RepHex A1 and RepHex A2), RepHex type B (RepHex B) and two ceramic frit double
junction electrodes (DJ1 and DJ2) as a function of time.
Figure 7: Increase in potassium concentration of deionized water solutions in
contact with RepHex type A, RepHex type B, and ceramic frit double junction electrodes
measured by ion chromatography.
Table 4: Physical Characteristics of Junctions Investigated
Page 21

WIPAC Monthly - May 2017

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