Water Quality

LOOKING BEYOND DISSOLVED ORGANIC CARBON TO UNDERSTAND WATER TREATABILITY

Cranfield University and Anglian Water have been working together under the umbrella of a strategic partnership to identify what the Water Treatment Works (WTWs) of the future will look like in the current context of water resilience, climate change, variable water quality at source and sustainability.

by Dr Irene Carra

Lecturer in Chemical Processes, Cranfield University

This long-term research is framed by the Water Resources Management Plan and aims at tackling current and future challenges with an integral approach, including organic matter, pesticides and other micropollutants, disinfection and disinfection by-products, biomonitoring and algae, amongst others. Part of this strategic programme is dedicated to the understanding of organic matter at source. Not all organic matter is the same and this research investigates two connected tracks –organic matter characterisation and its treatability.

Anglian’s surface waters are characterised as lowland sources, where organic matter has input from agricultural and anthropogenic sources. They contain low to medium Dissolved Organic Carbon (DOC) concentration and high ionic content, including alkalinity. Whilst lowland waters’ organic content may be lower than upland sources, it can be more persistent to conventional coagulation, particularly in the presence of alkalinity which discourages pH optimisation from a sustainable and cost perspective.

Our research has focused on the characterisation of these lowland sources and the efficiency of conventional and new processes in removing organic matter. This effort is based on the evidence collected over recent years showing that the organic compounds in 5 mg/l DOC in a reservoir in the eastern Anglian region are different to those in 5 mg/l DOC in a river in the western part of the region.

Sophisticated analytical techniques are used to provide information on molecular weight distribution, size, charge density or fluorescence, which in combination can provide a treatability profile for each source. An additional driver to characterise organic matter and its treatability is the future complex movement of large volumes of water across the region through a strategic pipeline to increase water resilience, with new water blends from different sources that may require advanced treatment.

Suspended Ion Exchange for lowland waters not amenable to conventional treatment

One of the water sources that has been studied as part of this research is the River Trent, a lowland river known to be difficult to coagulate, from which Hall WTW directly abstracts water to provide drinking water to the Lincoln area, and which will be part of the new strategic pipeline to move water across the region. A characterisation campaign has been undertaken over three years, capturing seasonality, and creating the fingerprint that represents the River Trent at the point of abstraction. Due to its challenging water quality, the River Trent has also been used to test new technologies for the removal of organic matter. Suspended Ion Exchange (SIX), patented by PWNT (Netherlands) has been available on the market for a few years as treatment for organic matter, quite often in combination with conventional coagulation. It is based on a fluidised bed process which uses a resin with high affinity for organic matter. The resin is separated in a clarifier due to its settleability properties and regenerated with chloride as a counterion. Although there is an overlap in the organic compounds SIX and coagulation can remove, they also target different organic fractions based on charge, size and hydrophobicity, which is why characterising organic matter becomes paramount to understand a source’s treatability. Although this type technology has been more widely explored for upland waters, SIX’s efficiency for lowland sources such as the River Trent has been less explored, particularly where coagulation is not a suitable treatment.

An 8-month SIX pilot trial was carried out at Hall WTWs to understand the potential of this technology for lowland sources not amenable to coagulation. It ran alongside onsite treatment for organic matter, GAC filters, to treat the River Trent’s water (Figs 1 and 2).

During the first five months of the trial, the GAC filters removed ca 60% DOC in the raw water, with certain variability around regeneration times. SIX removed up to 70% DOC with a consistent treated effluent concentration. Despite DOC removal being only 10% higher with SIX, the specific organic compounds

Fig 1. SIX pilot trial set up.

FEATURE: WATER QUALITY

being removed by each process were different, as indicated by molecular weight distribution, hydrophobicity and charge density analysis. This had an impact on chlorine demand, trihalomethane (THM) and haloacetic acid (HAA) formation potentials.

Despite SIX’s efficiency in removing organic matter from this source, operational challenges have also been identified during the trial. Brine waste for one, with high organic matter and ion content removed from the raw water, raising issues around its disposal. Reuse of this type of brine is under research elsewhere, but far from implementation. Large-scale plants where SIX has been implemented have opted for sewer discharge as the most practical option.

Another challenge comes precisely from the high efficiency SIX has shown in the removal of anions in water. Sulphate and bicarbonate are particularly well removed by SIX, while chloride is released during the ion exchange process. This promotes an increase in the Larson corrosivity index, making the SIX treated effluent potentially corrosive and with a subsequent risk to lead release in the network, even after brine optimisation. Based on this finding our research is now focused on using bicarbonate as regenerant to decrease the Larson index and water corrosivity. Shortterm results have been positive, with organic matter removal and THM and HAA formation potential similar to chloridebased regeneration. More difficult to account for are the potential additional benefits downstream of SIX. Namely, the potential for less chlorine for disinfection; UV-based processes such as disinfection or advanced oxidation would benefit from higher UVT and less organics; if ozone were part of the flowsheet, a possible decrease in ozone demand and lower ozone doses; and potential lower disinfection byproduct formation.

Fig 2. SIX pilot plant.

Ongoing research

Our research on alternative regenerants continue in collaboration with PWN (water utility in the Netherlands), where modelling is being used as a tool to estimate long-term responses of SIX when using bicarbonate.

Characterisation of organic matter at source continues and will play a key role in the near future, with the new water blends in the not-so-distant horizon. Moving from DOC towards more sophisticated tools will provide each source with a fingerprint that can be linked to the most suitable treatment strategy and inform catchment risk assessments.

ATI UK

CONTINUOUS MONITORING OF SLUDGE BLANKET LEVELS

ATi UK’s Senior Service Engineer, Mark Holmes, discusses the cutting-edge technologies available for measuring and monitoring sludge blanket, providing optimum efficiency and flexibility through smart, ultrasonic and continuous, real-time measurement.

Measuring and managing the depth of sludge blanket is one of the most critical challenges in the production of good-quality effluent from wastewater treatment plants. Aside from lessening the environmental impact of human waste, modern wastewater treatment plants have embraced advances in science and technology that allow significant, positive inputs, such as producing energy from biogases, such as methane, and in some cases generating revenue streams from processed biosolids, including nutrient-rich fertiliser for farming. However, for these advanced systems to work effectively, one of the most crucial parameters for plant operators to monitor is the total solids, or sludge, as it moves through the plant.

Although the composition and concentration of sludge varies throughout the treatment pathway, understanding the settling characteristics of sludge is vital to optimise control of the plant and wastewater process. Primary sedimentation, biological stages, secondary treatment, effluent quality, and subsequent sludge handling are all greatly affected by how well the settling has been achieved and, importantly, monitored.

Effective Automation to Improve Process Control

By measuring sludge levels in both primary and secondary sedimentation tanks, operators can ensure sludge extraction pumps are used efficiently and ensure poorly settled sludge does not carry over into effluent paths. By measuring sludge levels, operators can study sedimentation characteristics of suspended solids in the plant, understand sensitivities due to disturbances and manage sludge levels to allow sufficient buffering for incoming hydraulic load variations.

While no two waste-water treatment plants are identical, the push to improve efficiency through automation and improved process control is a common theme. Relying solely on manual sampling means that thorough analysis of plant characteristics and trends is limited to the frequency of sampling, with the addition of labour costs. In a plant with continuous, automatic measurement of critical process variables, there is a wealth of feedback that creates a robustness of system control, capable of rapidly identifying disturbances or operational problems.

Contactless sludge blanket level measurement

For measuring the depth of sludge blanket, two conventional methods are widely used; contact and contactless methods. The contactless method is considered more desirable, as it doesn’t depend on direct measurement by human operation. One leading example of contactless measurement is ATi UK’s EchoSmart, designed for superior sludge level detection in a wide range of water and wastewater applications. The EchoSmart sensor generates an ultrasonic sound wave that propagates through a liquid medium and is reflected back from material that is present in the vessel, which are typically settled solids, suspended solids, or the tank bottom. The sound wave travels at known velocities, providing the ability to convert elapsed time into Range and Level measurements, offering continuous, realtime measurement. The underwater acoustic measurement principle allows the sensor to track well settled blankets, as well as being configured to track dispersed solids, such as ‘fluff’ or ‘rag-layer’.

The EchoSmart sensor does more than just produce a raw signal; it is equipped with an advanced programmable microprocessor and dynamic memory. Through these facilities, the sensor provides all signal control, enhancement and interpretation, and determines the final process measurement. The smart sensor also communicates with an EchoSmart Controller via digital communication, offering greater flexibility in equipment configuration options, enhanced communication capabilities and reduced installation costs.

Flexible, smart networked monitoring

EchoSmart can be used for a wide range of applications and industries, such as sludge thickeners in wastewater, primary or final settlement tanks, and also within the clean water treatment process, including clarifiers on water treatment works. It is adaptable and can be programmed to suit various shapes and tank sizes, with the additional option for turbidity measurement, offering further insight into tank and solids activity, which is useful for less dense blankets.

There are also options available for a variety of installation requirements, including a remote or local controller, a stand-alone system, or alternatively a network of up to 16 sensors can be added to one controller. Communication can be achieved through hard wired connections or radio-link network, which can eliminate the need for costly installation. The system comes standard with analogue and digital outputs, as well as Modbus, but other digital communications can be attained if required.

The EchoSmart sludge blanket level monitor is simple to install and operate, providing an advanced yet user friendly solution, offering cost effective, trouble-free and reliable measurement.

EchoSmart and FilterSmart. Eliminating the guesswork from sludge blanket and gravity filterbed monitoring.

EchoSmart FilterSmart

The ATi UK EchoSmart controller is an underwater, interface level analyser for sludge blanket monitoring. It will eliminate the guesswork from sludge blanket measurements in clarifiers, thickeners and anywhere an underwater interface measurement is needed.

Built on a digital platform with technology which allows users to locate the analyser in the sensor. Our sensors generate and process the ultrasonic signal for continuous, real-time measurement, resulting in greater flexibility in equipment configuration options, enhanced communication capabilities and reduced installation costs.

EchoSmart interface level analysers are unique. Our smart-sensor technology enables users to control up to 16 smart sensors with one EchoSmart controller, with either wired or wireless configurations. These options allow for a field network of sensors to be created, offering support for even the most challenging processes. The ATi UK FilterSmart monitor is an interface level analyser incorporating a turbidity sensor and configured to the unique requirements of filter applications. Built on our EchoSmart digital technology platform, FilterSmart outputs results that are specific to gravity filters, namely media level and turbidity. The FilterSmart sensor is located in the top of a gravity filter just below the top of the wash trough. During a backwash, the ultrasonic sensor tracks the level of the media and the turbidity sensor measures how clean or dirty the wash water is as it flows into the wash trough. These two simple measurements produce trends that together provide an extremely accurate profile of the backwash, allowing the operator to ‘see’ into the process like never before.

FilterSmart virtually eliminates media loss and mud ball formation and leads to better filter health and efficiency.

sales@atiuk.com / +44 (0) 1457 873 318 / atiuk.com

ATi UK is a leading provider of engineered, analytical sensor monitoring solutions for water and gas applications and data analytics. Our pioneering and industry leading range of Smart Network Monitors, Water Quality Monitors and Gas Detectors provide innovative solutions for the most demanding of applications.

IS WATER QUALITY THE POOR RELATION TO LEAKAGE?

We are living through interesting and testing times. One of the silver linings of the pandemic is that the world has become more connected; there is a real spirit of collaboration to tackle some of the issues we face.

by Michael Strahand

SWAN Ambassador and SWIG board member

This increased connectivity has made it abundantly clear that we as a race face some common problems, many of which involve our world of water. What are some of these “wicked problems” (as Will Sarni CEO of the Water Foundry calls them) that challenge us daily? Water scarcity, water inequality, water poverty, water pollution, water contamination are problems all around the world.

Water water everywhere but how much can we drink?

Our world of water is awash, pardon the pun, with talk of digital transformation and leveraging the power of big data and the IoT to make the world of water a better and maybe a fairer place.

When I survey the drinking water supply landscape from my vantage point as a SWAN Forum Ambassador and SWIG board member, I see some amazing progress in the field of leak detection and leak reduction. The price and complexity of leak detection technologies such as noise logging and pressure logging have tumbled in the past couple of years to allow water utilities to deploy sometimes tens of thousands of sensors to locate leaks more efficiently and effectively. AMI (Advanced Metering Infrastructure) harness smart water meters, data communications infrastructure and data analysis to unpeel the leakage onion and identify for example customer side leakage.

Finding and fixing leaks makes sense, why treat water to throw it away?

Amongst all this activity though, what is happening in the vital area of water quality?

In the developed world, the production of water is a well understood and well

FEATURE: WATER QUALITY

controlled process. The measurement of the quality of raw water and of the final water is a vital part of the process. Online water quality monitors control filtration, coagulation and disinfection to high levels of precision and accuracy and with adequate levels of reliability.

Once the water leaves the treatment facility and goes into supply it is a different story. The only thing we can say with certainty about the quality of water as it makes its way from a treatment facility to a customer’s tap is that it does not improve (secondary treatment notwithstanding).

Water quality deteriorates as the water moves through the system. For example, discoloration caused by flow changes shearing material off the inside of pipes, contamination due to ingress and loss of disinfectant with time all lead to decreasing aesthetics and more importantly to a possible increased health risk.

Why then is there so little investment, relatively speaking, in water quality measurement in water supply networks? The reasons that fall into three categories. 1. Legislation: Legislation around leakage, especially in the UK, with very demanding targets, drives investment towards leakage measurement. The compulsion to measure water quality in water supply networks is not so strong. 2. Sensors: The current generation of sensors are often too complex, too expensive, too large, too power consuming to encourage deployment in the numbers needed. 3. Business case/ROI. Compared to leakage, it is harder to make a business case for water quality, will measuring water save money or increase revenues?

The good news is that things are changing.

The objective of the Directive (EU) 2020/2184 of the European Parliament and of the Council 16 December 2020 is “to protect human health from adverse effects of any contamination of water intended for human consumption by ensuring that it is wholesome and clean”. The World Health Organisation (WHO) Guidelines for Drinkingwater Quality sets out recommended maximum levels of hundreds of known water contaminants. The EU directive came into force on January 12th this year. All water companies with more than 50,000 connections are now compelled to develop water safety plans and increase the amount of water quality monitoring.

The directive has “reinforced water quality standards which are more stringent than WHO recommendations.” Some key features are: ■ A preventive approach favouring actions to reduce pollution at source by introducing the “risk based approach”.

This is based on an in-depth analysis of the whole water cycle, from source to distribution. ■ Measures to ensure better access to water, particularly for vulnerable and marginalised groups. ■ Measures to promote tap water, including in public spaces and restaurants, to reduce (plastic) bottle consumption.

This strengthened directive’s objective and the WHO Guidelines are focussed on and concerned with water quality. How do these documents and the appetite for digital transformation come together?

To truly unlock the potential of the IoT and the power of machine learning and AI there is a need for simple, inexpensive, reliable water quality sensors that will act as gatekeepers, as human health guardians. This next generation of sensor will allow water companies to comply with the law and much more importantly to minimise the risk to public health.

In our rush towards digital we often forget the biggest analogue element of the journey, people. Whatever equipment we deploy must be accessible to all. A poll in a recent webinar run by Aquatech Global Events identified people skills as a key water quality challenge. If water quality sensors require skilled technicians to install them and skilled technicians to keep them working, they can only be deployed in areas where those skills exist and where the skills are not expensive.

Most water quality sensors currently deployed in water supply networks started life as analysers that automated a laboratory technique, they evolved out of the lab into the world of process control. The purpose of most water quality monitors is not to protect health, it is to control a process, these are different things. The next stage of water quality sensor evolution is to make them fit for the purpose of “protecting human health from adverse effects of any contamination”.

Great products are emerging now that fit the need, that answer the “why?”. Autonomous IoT enabled sensors for catchment monitoring, sensors for river monitoring, sensors for in-pipe water quality monitoring are coming to market. They are not all coming from the traditional water supply chain. It is to be hoped that innovation initiatives and funding opportunities around the world accelerate the evolution of the much-needed next generation of water quality sensors. What happens when we have this next generation of monitors? All these products will still rely on people to use them and people to make decisions based on the information and insights they offer up.

Who are, or who will be, “the people”? More and more the white-haired middle age (mostly men) people are leaving the water industry to be replaced by millennials who want to work for something more than a paycheck and security. Our water industry needs to attract them in bigger numbers and make the water sector exciting and meaningful. Focussing on quality, public health and wellbeing, as well as leakage, is far more likely to bring millennials into the sector.

That is a good enough reason on its own to get water quality up the agenda.

In conclusion, “Is water quality the poor relation to leakage?” Maybe not the poor relation but it is the quiet relation whose voice needs to be heard!

IT ALL STARTS WITH A RELIABLE SOURCE OF CLEAN WATER

Nearly every part of the world has experienced the effects of climate change through increasingly unpredictable, intense weather.

Despite a fall in carbon emissions last year due to COVID-19 restrictions, the climate crises continued and 2020 was one of the joint hottest years on record. We’ve witnessed wildfires in Australia and the United States, floods in China and Japan, and storms in the Americas, and the UK has not escaped unscathed from the impacts of climate change.

And while the climate crisis manifests in a range of erratic weather, it is through water that its most immediate impacts are felt. For the billions of people without access to a safe, reliable supply of clean water, these impacts are catastrophic.

WaterAid’s upcoming report to mark World Water Day shows that without a reliable source of clean water, the world’s poorest communities will struggle to withstand the rapidly changing climate. The greatest injustice is that the people who have done the least to cause the crisis are the hardest hit and least able to adapt.

As water becomes scarcer, people – mostly women and girls – must walk further to access it, affecting education and livelihoods. This exacerbates ever-growing inequalities, within and between countries.

Tackling climate change

Many industries are showing a strong commitment to tackling climate change, with the water sector leading the way in becoming the world’s first industry to commit to net-zero carbon emissions by 2030 to help mitigate the extreme impacts of the climate crisis.

While the reduction of carbon emissions is crucial in dealing with climate change, it must go hand-in-hand with developing sustainable climate adaptation plans, enabling communities around the world to cope with whatever the future holds.

Collaboration is key

The scale and interconnected nature of universal access to water, sanitation and hygiene (WASH) and climate change means these issues cannot be dealt with alone; collective action is critical to tackling these interrelated crises; the private sector, utilities, including the UK water industry, government and NGOs must all work together in a coordinated and collective way.

Through our work with the UK water industry over the past 40 years, WaterAid has been able to deliver reliable water facilities that keep operating through disastrous weather, while ensuring communities are equipped with the skills needed to manage and maintain water infrastructure.

But there’s still more to do to ensure all have access to safe, accessible water by 2030, in line with the UN’s Sustainable Development Goal (SDG) 6, as the more our climate changes, the more challenging this becomes. With expertise in adaptation and mitigation, WaterAid and the water companies are hoping to fulfil SDG 6 together. And with the world’s most important forum on climate expected to take place in the UK in 2021 COP 26, it will bring the debate closer to home for many of us.

This year, as the world makes big decisions on how to recover from a global health crisis, we have a once-in-a-generation opportunity to create a greener, fairer society. This is our moment to amplify the voices of the communities living with the devastating impacts of climate change on their water sources. And bring us closer to a world in which everyone, everywhere has access to clean water that they can rely on, today and long into the future, whatever our changing climate brings.

WaterAid/ Drik Picture Library Limited/ Farzana Hossen

WaterAid’s annual World Water Day report will be available on washmatters.wateraid.org from 22 March.

Nearly five million people in Bangladesh don’t have clean water close to home.

This is a women’s group in Manik Khali village in the Assasuni district. Most of these women have tubewells in their courtyards for their water, but they contain high levels of salt, brought in by rising sea levels caused by climate change. As a result of coming into contact with the saline water, many women in this group have skin allergies, experience hair loss, and often suffer from diarrhoea. To get clean water they are forced to walk miles to another tubewell.

WaterAid is working with Severn Trent to improve access to water and sanitation services for 100,000 people in the area. Up to 80 women will be trained in the operation and maintenance of reverse osmosis Water Treatment Plants and entrepreneurship.

HACH

IMPROVED AMMONIUM CONTROL AND ENERGY SAVINGS IN ACTIVATED SLUDGE PLANTS

Thames Water’s Beckton STW in East London is one of Europe’s largest wastewater plants, treating an average flow of 1,150,000 m3/d.

by Russell Baxter,

Process Municipal Sales Consultant

Martin Butterfield,

Application Development Manager (RTC)

& Richard Addison

Municipal Projects Manager

It was identified that one section, ASP4, treating 30% of the site’s flow had issues, despite the fact that with 7.5 m deep aeration tanks and variable speed aeration blowers this should have been the most efficient plant out of the three ASPs on site.

Initial performance was disappointing and after several investigations the decision was taken to modify the ASP under a “spend to save initiative” as energy costs at the site were in the region of £8M per annum. The project was carried out in 2 distinct phases to address both the process issues and reduce energy consumption.

The first phase involved refurbishing or replacing existing air valves and automating a number of others in the aeration lanes, increasing the number of dissolved oxygen (D.O.) measurement and control points along with the associated changes to blower controls supplying air to the plant.

As an extension to the first phase it was discovered that the ASP’s anoxic zones were not functioning correctly due to excessive residence times in the pump wet well. At times this was allowing anaerobic conditions to develop in the ASP’s anoxic zones promoting foaming. In order to ensure that the anoxic zones functioned correctly these were converted to dual function ‘swing zones‘ which can be either aerated (aerobic) when nitrates are low or just mixed with static mixers (when in anoxic mode) when nitrate concentrations are sufficient.

The project’s second phase involved installing HACH’s N-RTC, measuring inlet and outlet ammonium concentrations and ensuring that the permit conditions were being met at least cost. After implementation it was found that D.O. levels were controlled more precisely and efficiently as each individual zone has its own motorised air valve and associated

FEATURE: WATER QUALITY

D.O. probe. The new valves are better suited to process conditions and to date have been trouble free.

Hach’s RTC system responds to incoming ammonium load and Nitrate levels. If insufficient nitrate is available for the anoxic zones to function the zone is aerated to prevent phosphorus release. If high incoming ammonium load is observed (such as during storms) the anoxic zone is switched to an aerated zone irrespective of nitrate levels to ensure that ammonium compliance is within permit conditions.

When sufficient nitrate levels are available and incoming load allows, the swing zone is run in an anoxic state to recover as much bound oxygen as possible therefore saving energy. Hach’s RTC system continuously calculates actual and possible nitrification rates. This ensures that when conditions allow, D.O. set points are lowered saving on air and hence energy. During high load periods the D.O. set points are increased to ensure compliance with permit conditions. The baseline starting point before modifications were implemented was 5.3 kwhr/kg Ammonium removed. Following the completion of both phases and commissioning of the RTC, the ammonium removal rate was improved to 3.8 kwhr/ kg representing an overall saving of 28% which equates to savings of approximately £0.5 million per annum and importantly a project payback period of just over 1 year.

Further work is now in progress to initiate the ‘sludge age’ controller in the RTC. This should allow further energy savings to be achieved anticipated to be 3.5 Kwhr/kg N removed.

The Success of this project is a result of foresight by Thames Water and making sufficient funds available to enable the modifications to be implemented. Additionally, the partnership approach between all stakeholders has allowed the goals to be met.

Our capabilities incorporate various market sectors, including business, industrial and housing developments. We have extensive experience and expertise working within the design of water network distribution & water network trunk mains.

From initial overview and preparation through to detail civil design, while also equipped to provide planning, project management and construction support services.

We would welcome the opportunity to visit you for an initial consultation to discuss your aims and needs. We would endeavour to incorporate our design and engineering solutions to match your business requirements.

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LONG TERM LEAD STRATEGIES

Hot off the press from the Drinking Water Inspectorate is a research report concluding three years work, led by WRc, gathering evidence and examining long-term strategies to reduce exposure to lead from drinking water.

by Mark Kowalski

Principal Consultant, Water Research Centre

by Joanne Hulance

Senior Project Engineer, Water Research Centre

by Robert Fairhurst

Project Analyst, Water Research Centre

by Frank White

Drinking Water Inspector, DWI

This research was commissioned to help inform policy development and strategies for dealing with lead from 2025, and is considered to be a major step forward in informing the next steps for the water sector. As Milo Purcell, Deputy Chief Inspector of the DWI commented: “We have been on quite a journey when it comes to dealing with lead – a journey that has been controversial at times, and in many respects frustrating as well – but we have an opportunity now to put greater focus on what remains as a lead problem with the main emphasis as a public health issue”.

Reflecting discussions in Europe regarding a recasting of the Drinking Water Directive on lead and following the scientific opinions of leading organisations including the World Health Organisation, the research has sought to quantify the impact of (a) reducing the lead concentration in drinking water to 5 µg/l by no later than 2040, and (b) achieving no detectable lead in drinking water by 2060 at the latest. The baseline year was set at 2025, and all policy options were evaluated against a reference scenario which is – broadly speaking – the status quo that is designed to achieve compliance with the current 10 µg/l standard. Analysis of recent compliance sampling shows that doing nothing more is not an option: a significant minority of water supply zones would not currently comply with a new water quality standard for lead of 5 µg/l or better.

Continued efforts to reduce lead in drinking water are being driven by the need to protect human health. In a recent webinar on the topic, Project Technical Lead Mark Kowalski explained that there is good awareness of the link between lead and neurodevelopmental effects in children – but there is also a growing body of evidence that chronic low-level lead exposure can have adverse health effects in the adult population, including chronic kidney disease, raised blood pressure and cardiovascular disease. The research explored the prevalence of environmental lead, including the contribution from drinking water, and used that to assess the health impacts of reducing lead concentrations in drinking water from the current baseline. Biokinetic models translate the lead concentrations found in environmental sources to a Blood Lead Level (BLL). The uptake of lead by the human body is a function of age, so two separate models were used to represent children and adults. Project Analyst, Robert Fairhurst comments, “although blood lead is dominated by exposure to dust and soil, the results of the project demonstrate that changes to the small contribution from drinking water can have a significant impact on the health of a population”.

Options for addressing lead in water were explored and a set of policy options that incorporate practical and achievable strategies for meeting a lower lead standard were defined. Economic modelling for both England and Wales was completed to look at the cost effectiveness of each option. Of these options for controlling lead, the project team reached the conclusion that the only feasible and enduring way to guarantee compliance with a 5 µg/l or better standard for lead in drinking water is to remove the lead service

Fig 1 – illustration of the costs and benefits included within the economic analysis

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Fig 2 – Modelled costs and benefits of lead pipe replacement in high risk zones in England and Wales (optimistic remediation outcome)

pipe – with replacement needed to either the property wall or, preferably, to the water quality compliance point (usually the kitchen tap).

For the study, the principle of materiality was used to restrict the economic analysis [Fig 1]. Contributing to costs are the cost of lead service pipe remediation (replacement) as well as the embodied carbon cost of new polyethylene (PE) pipe.

Contributing to benefits are the avoided adverse health effects, a reduction in cost of upstream conditioning (including orthophosphate dosing), the cost of water saved from reduced leakage, and the lead scrap value of removed pipes. These avoided costs included both a direct and carbon component when applicable.

The research was keen to explore a variety of lead remediation options. However Senior Project Engineer, Joanne Hulance, explains many intervention options had to be rejected as their benefits could not be sustained or guaranteed for the longer term. Lead pipe replacement to the property wall does not eliminate all lead, and this gives lower health benefits as a result, making this a much less cost-beneficial approach than lead pipe replacement to the kitchen tap. The research concludes that lead pipe replacement to the kitchen tap should be cost-neutral or better in water supply zones at high risk of non-compliance, as well as for most medium- and low-risk water supply zones in England. Provided that lead pipe replacement to the kitchen tap reduces lead concentrations to below the limit of detection, replacement to the kitchen tap would also be cost-neutral overall in Wales. Baseline lead in water concentrations in Wales were found to be lower than that for England – which is why the same lead exposure mitigation policies appear less cost-beneficial in Wales compared to England.

Rather than defining a roadmap to compliance, the research outputs have been designed to inform the debate about the standards, approaches, pace of delivery and priority actions. The research has been made possible with contributions from many organisations including water companies, Public Health England and Public Health Wales, DEFRA economists and water policy advisors, water industry economists and UKWIR. DWI has supported preparatory investigations in the current price control period for many companies in England and Wales and there are now proposals for pilot studies coming forward under the Green Recovery Programme – some of which will be significant over coming years. These will further inform the evidence base for the enormous programme of work that is anticipated to be needed. The hard work has begun with the planning and provision for this work to be done now so that it can be included in the PR24 business plans.

In concluding remarks at the report launch event Milo commented: “We have the foundations of something special here and indeed we consider that this asset management programme is likely the most significant contribution to public health that the water industry in the UK can take for a generation”.

The full research report can be viewed

here https://www.dwi.gov.uk/long-termstrategies-to-reduce-lead-exposure-fromdrinking-water/

GROUNDBREAKER

TAKE THE LEAD ON LEAD

Awareness of the potential health problems caused by lead in the water supply, particularly in infants and children is growing.

Houses built before 1970 would have been constructed with lead water supply pipes and if still in place can be causing developmental harm to young occupants. Although the use of lead in plumbing has been banned in the UK for more than 50 years, there are still many properties where a risk of lead contamination of water is a risk. In some areas of the UK up to a third of these older properties are still receiving their water through these original lead pipes1 .

In properties with lead supply pipes, the only totally secure method to reduce lead levels in the water supply is to replace the original supply with modern plastic pipe. These new materials can also provide the additional benefits of improving flow rates and reducing pipe noise.

Traditionally, any lead replacement program requires major excavations outside a property and causes huge disruption within. Resulting in mess and disturbance to householders over several days. This disruption has often been the cause of users’ reluctance to have the work undertaken.

Replace lead water supply pipes in under 2 hours…no major excavations, minimal disruption with INSUduct®

INSUduct® is an innovative solution. Minimising disturbance, time and cost.

Unlike traditional methods, INSUduct® allows the new water service to be routed up the external face of the building and connected to the internal plumbing above ground level, whether this is the ground floor or upper storey. In multi-occupancy properties INSUduct® allows multiple supply pipes to be installed, as it is

designed to provide frost protection for up to three 32mm OD water pipes installed to the exterior of the building.

INSUduct only requires one simple core drilled hole through the wall, at an appropriate point to connect with the internal plumbing. This enables most water supply replacements to be completed within a couple of hours, without the traditional mess and disruption to the householders or occupiers. The improvement in work efficiency and reduction on the impact to occupants is a win for both contractor and customer. There is also little impact to the exterior appearance of the property, as the INSUduct system provides a neat, clean finish to the job.

Groundbreaker products are designed to provide long lasting and effective thermal protection to water pipes and fittings outside the thermal envelope of a building. They offer frost protection for 3 days or more with temperatures as low as -15°C, temperatures we rarely reach in the UK - even with today’s erratic climate! Carefully fabricated to provide long lasting and effective thermal protection to water pipes and fittings in external situations, the products exceed British Standard 5422 and all relevant Water Regulations for frost protection and is on the “approved list” of most UK water companies.

Steve Leigh, developer of the range and Managing Director of Groundbreaker, has over 40 years’ experience in the Water Industry. “We’ve been putting pipes in holes in the ground to protect them from frost for decades,” he explained. “Although it works, todays new materials allow for a much better solution. Keeping pipes on the surface reduces the risk of leaks developing and allows for easy repair and maintenance. It’s just a must better method of working.”

This isn’t just Steve’s opinion in 2018 Groundbreaker were recognised by the HBF (Home Builders Federation) as the Utility Company of the Year for their innovative range that meets the highest standards in both product specification and leak free installation design. The company is also a contributor to the recently launched BPEC (British Plumbing Employers Council) Groundworker, Service Pipe and Meter Housing Installation Training course2. The course highlights the elements of the Water Supply (Water Fittings) Regulations 1999, relevant to groundwork and ensures contractors have met the minimum competency requirements for entry into WIAPS Approved Contractors Scheme (Groundworker Section).

Lead Water Supply replacement has become a priority for water companies across the UK. Systems such as Groundbreaker can overcome user reluctance and provide and time and cost-efficient methods of water supply pipe reluctance.

FEATURE: WATER QUALITY

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1. https://www.lovemoney.com/news/19726/themost-common-home-insurance-claims 2. https://bpec.org.uk/qualification/groundworkservice-pipe-and-meter-housing-installation/

SMART THINKING, SMARTER WATER

ATi UK’s Technical Performance and Data Analyst, Derek Leslie, discusses why putting the customer’s individual needs first has never been more important for the future of smart water.

Digitalisation is bringing new possibilities for managing water utilities more efficiently and resiliently to proactively safeguard water quality and create intelligent, optimised, Smart Water networks. As the emphasis on the future of Smart Water rises, water professionals are becoming more focused on finding the right, tailored solutions that help to improve water quality, by extracting deeper insights on pipeline networks and enhancing operational efficiencies.

The entire water industry has been entrusted with the responsibility of supplying vital water services to communities, safeguarding water at all points on its journey from source to tap. As custodians of this journey, we are also responsible for continually developing innovative solutions to manage these systems efficiently, effectively and in a transparent manner.

Until recently, utilities lacked the tools to manage our ageing water systems and proactively manage water quality, however, advances in digital technologies are now enabling better knowledge, system hygiene, more efficient monitoring, diagnostics and targeted investments, along with intelligent system management.

It has already been proven that collaborative, intelligent, networked systems are the key to the future of water management, assisting in identifying and predicting water quality issues. But they also improve operational tactics, promote conservation, minimise consumption and offer 24/7 reassurance that safe and wholesome water is being delivered to communities and this is what is helping to drive the industry towards becoming truly smart. However, as is the case with most problems, there isn’t a ‘one size fits all’ solution. This is where technical innovation and collective expertise play a vital role.

As an example, if a car dealership revealed the last 20 cars that they sold, very few would be the exact same model or specification. This is because customers buy a car based on their specific requirements and budget limitations, essentially selecting a bespoke model fit for individual needs. So why should the water industry be any different, forced to follow the crowd when it comes to what defines Smart Water? The simple answer is, it isn’t.

New technology enables the bespoke design of water quality monitoring systems for a variety of applications. Like cars, the basic monitors are similar, as all water companies monitor leakage and pressure pretty much as standard, but different options are then available to build modular systems to suit individual site requirements. This is what makes the systems truly smart. By taking the time to listen and understand what each water utility’s individual needs and challenges are, working together with skilled, multi-technology partners to create tiered options, results in bespoke solutions tailored to specific needs.

FEATURE: WATER QUALITY

However, it is important to remember that one water professional’s ideal Smart Water solution will differ from another’s, depending on the application and the ‘pain’, even from within the same water company.

Scalable, smart network solutions that can be customised for different applicational needs are fast becoming a prerequisite, rather than a luxury. These solutions require a truly smart approach, one driven by data, innovative technology and collaboration, allowing utilities to select the functions they need to tackle the problems they are facing, adapting to meet their changing needs over time.

Network Automation Control Systems

While Smart Water offers untold benefits, utilities are still working to understand how to gather, manage, analyse and action the data being generated by ever-evolving new technologies. The only problem with Big Data is that we can often become overwhelmed by the amount of information we receive. Understanding and interpreting this data is an essential part of the puzzle if we are to achieve true Smart Water.

This is where network automation is needed to be able to progress from what is currently being badged as Smart Water to the next advance in technology. To combine the controls of flow and pressure with water quality data, offering early warning alerts to events, must be the goal ahead. The end result does not have to be a singular, a one size fits all, much like the choice of car and model. A modular approach to control systems is what the industry requires.

At the moment, the understanding of this complex data and ensuring you get the best value from your investments comes down to people. People within water companies, academia and consultants that can tell you what this all means and when things are happening within your networks.

With the right sensing technology, tailored to specific needs and detailed data analytics, there is sufficient and accurate information to optimise treatment, cost, protect assets and predict the future, whilst avoiding issues in the present, but only if you have the correct focus on ‘data to decisions’

Collective Expertise

The final piece of the Smart Water jigsaw is empowering water companies and the supply chain to be bold enough to turn innovations into business-as-usual processes and streamline activities to ensure effective collaboration. The challenge moving forwards is to learn from each other by sharing best practice, information and expertise for mutual benefit. What wisdom is there in several companies repeating similar trials and tests only to produce the same results?

Sharing must also involve people and skills. This includes academia, such as The University of Sheffield, Manchester University, and Imperial College, that work alongside the water industry to carry out independent studies and trials. There are manufacturers of sensors, loggers, control systems, data analysts, IOT and water consultants, all of whom have an immense repository of skills and knowledge for us to tap into and develop. Sharing experiences would quickly enable the industry to foster best practice in both Smart Water quality solutions and processes, encouraging the much-needed formation of multi-layered, multi-faceted, strategic partnerships rather than working in silo. Transparent collaboration, with shared values to improve the industry, is what will help us to achieve the goal of true Smart Water.

The onset of the digital revolution is bringing the possibility of comprehensive Smart Water networks ever closer. It is essential that, as an industry, we innovate and grasp this opportunity with both hands; this will lead to greater efficiency, improved network performance and enhanced customer service in an everdemanding business environment.

The challenge now is to keep evolving and work smarter, developing new, innovative, customer focused technologies, with inter-disciplinary ways of working that are motivated by the goals of each individual project, tailored to the applications they are used in. Digital innovation will be the key to success and survival, enabling organisations to build a connected workforce, modernise operational processes and deliver enhanced customer service. Smart Water is changing the water industry as we know it and embracing innovation and digital transformation is not only enabling utilities to address today’s unprecedented challenges, but also invest in the future.

BRITISH WATER ENGINEERING COLLEGE

ARE YOUR PEOPLE TECHNICAL ENOUGH?

When I was doing my A levels, Chemistry, Physics and Pure Maths, I had to know and be able to answer questions about electronic orbitals configurations and the order they were filled in, the equations of motion and be able to differentiate and integrate equations from first principles. And I still can to this day. Truly gifts that keeps giving.

Today an level 3 qualification is held to be the equivalent of A Levels. So why am I not seeing topics like I studied when delivering L3 courses? Also why is there a move away from the broader courses like the Water Operations s HNC and the Cabwi L4 diplomas in favour of shorter, more specialised courses?

One argument is that the current L3 technical courses are more practical, focusing on the “what” rather than the “why”. I disagree with this.

My first reason is personal. I feel I perform better because I have a wide-ranging technical background, and both a Cranfield MSc, which has whole new meanings for the word “technical”, and an MBA. Together they give me a wide variety of problem solving tools.

Does it actually work? Well, for nearly five years in the last eight I have been doing nominally full-time interim roles on three days a week contracts. And did other work, had days off and enjoyed a sensible worklife balance.

My second reason is that I see individuals who delve into the “why” seem to have better career outcomes than those who are just happy to pass tests and exams. This is subjective, but I stand by it as an opinion. I also see something similar for those who take an interest in what goes on in other parts of their organisation.

Sadly, organisations are increasingly employing people in narrower, more specialised, roles in the interest of efficiency. I argue that this is a false economy in the medium term. I foresee the most talented individuals becoming

frustrated by narrow job roles and looking to broaden their experience elsewhere.

Remember, we are in a period where something like a third of the utility sector workforce is reaching retirement age in the next five years. Yes, a third. Also, there are fewer young people in the population and the young people in the jobs market are turning away from STEM studies.

This is not a great time to risk losing your best pest people. And it is your best people who will find it easier to get another job. What can you do about it? Think about what your people want from a job, typically wanting it to be fulfilling and rewarding, and above all to be appreciated.

Studies have shown that wider ranging jobs and offering development opportunities helps with attracting and retaining staff. For example, graduates consistently put development opportunities ahead of salary when considering potential jobs.

BWEC can help you, too. If you have an idea for a broader based approach for the training and development of your workforce that current qualifications don’t cover, give me a call.

I’m currently doing this with a new qualification on Reverse Osmosis for the AquaGib, aka Gibraltar Water. With a newly developed unit, an adapted unit, and an existing unit they have a training pathway that really suits their situation.

Why settle for what you are being offered? Give your people what they really want.

About BWEC

At BWEC (www.bwec.org.uk) we love creating a course or development programme which is exactly what you want. It’s straightforward and inexpensive, and you get the benefits for years to come.

If you are interested in finding out more, please get in touch for a chat. M: 07554 994855 E: bob@bwec.org.uk

FEATURE: WATER QUALITY

TRADE EFFLUENT: THE DARK ART EXPLAINED

When I was presenting a webinar recently Trade Effluent (TE) was introduced as the ‘dark arts’. So, this article attempts to shed some light upon the subject, demystify it and make it accessible to all.

by Nick Womack

Trade Effluent Specialist, Blackwell Water Consultancy

A Little History

TE has a long history. Sewerage Undertakers (SU) are the statutory regulators of TE services in their licenced area with powers set out in the Water Industry Act 1991. This carries forward legislation contained in 1937 Public Health (Drainage of Trade Premises) Act which was the first to deal specifically with authorising industrial discharges to sewer. However, the contents of that Act can be traced back to the Public Health Act 1890 which first introduced prohibitions on discharging certain substances into sewers, developing the earlier Public Health Act 1875. So, the current legislation harks back to the Victorian age and still contains clauses relevant to then, Section 111 specifically prohibits the discharge of ‘carbide of calcium’ to the public foul sewer (PFS).

For those of you who don’t remember … dripping water on to calcium carbide (Ca2C) produces acetylene (ethyne) gas which was then burnt to provide light in lamps. Presumably this was included in response to incidents of sewers exploding due to careless disposal. Water UK worked with DEFR in 2010 to modernise the legislation under the ‘Red Tape Challenge’ (RTC) initiative but, so far, the legislation remains unchanged. Perhaps more important matters came along!?

There is a right to discharge domestic sewage to the PFS. Domestic sewage is not legally defined but ‘domestic sewerage purposes’ are and refer to the removal of the ‘contents of lavatories’ and ‘water used for cooking and washing’.

TE however can only be discharged to the PFS with the SUs permission.

What is Trade Effluent?

TE is wastewater derived from industrial processes. However, it is not tightly defined in law although over time legal opinions have been offered and judgements made which have made the interpretation clearer. For example, it was determined in 1980 that effluent from a launderette was TE even though its contents are identical to that from a washing machine at home. The key principle established was that the water was produced as part of a business and so was TE.

In many cases it is clear that a discharge is TE, for example wastewaters from food factories or rinses from engineering plating shops. Others such as the discharge from fish pedicure tanks or the water from the emptying of ornamental fountains are a grey area whilst discharges from take-aways and restaurants are not determined to be TE by all SUs.

Why do we need to control it?

The 4 Ps - People, Plant, Processes and Products/Permits.

Unregulated discharge of industrial wastes can harm those working on the sewerage network or at receiving sewage works, most often reported is staff being impacted by the release of noxious gases.

Chemicals can also damage or corrode pipes and pumps in sewer networks or at sewage works. Chloride (salt) is a good example, particularly if associated with warm discharges.

Sewage works rely to a significant degree on biochemical processes to clean wastewater and these are impacted by toxins. There has been a recent case of a discharge of cyanide effectively ‘killing’ a sewage works. Potentially disastrous environmental damage results from both the toxin itself and the pollution caused by untreated sewage. Such discharges can also harm staff working on the sewerage infrastructure.

Lastly sewage works have permits to discharge which will contain a variety of chemical limits set to protect the receiving water course. For example metals which, although they may be partitioned in sludge and reduced in concentration, are not in any way destroyed during treatment. Regulating metals helps to ensure compliance against both final effluent permit levels and limits in sludge.

How is it regulated?

People who wish to discharge TE to the PFS must therefore seek permission or consent from their SU, in legal terms they are required to ‘serve notice’ on them. The permission granted is commonly known as ‘a consent to discharge’, or simply ‘a consent’. The RTC work recommended that the archaic term ‘a consent’ be changed to ‘trade effluent permit’ or similar wording to bring it into line with other environmental legislation terminology.

The law requires the SU to decide whether or not they can accept the effluent and

FEATURE: WATER QUALITY

what conditions they will apply to the discharge such as a total volume and rate of discharge and a range of chemical limits. These will depend on the nature of the discharge but normally include chemical oxygen demand, settled solids, pH and temperature. Food wastes which are high in fat should contain limits on fats oils and grease but probably not heavy metals whilst those from a galvanising plant will not require a fats oils and grease limit but will require a limit on zinc and perhaps associated metals. The art of the TE practitioner is to set limits that a fair to the discharger whilst protecting those 4 Ps.

In reality most companies producing TE have little alternative other than to discharge it to sewer. A direct discharge to the environment may be too far away and anyway will only be allowed by the EA if there is no suitable alternative route for disposal and even then, the conditions applied are necessarily likely to be more stringent than those applied to a discharge to sewer. Tankering away may be a solution for small volumes of hazardous waste but not for most where the costs will far outweigh the charges applied by the SU (charges are discussed below).

As TE dischargers will normally be reliant on obtaining a TE consent to operate profitably allow, it is important that SU’s apply consistent rules in determining a request to discharge. Their decision should be fair, equal to all and transparent. In reality an application may require discussions and perhaps compromises for it to be accommodated. If no agreement can be reached (eg the SU perhaps wants tighter flow or load limits than the discharger is able or willing to meet) then the discharger has a legal right of appeal to OFWAT who have the powers to set consent conditions. It is rare that they intervene so radically, but it is important that all TE dischargers are aware of their right of appeal and that the SUs can be called to account.

When working as a regulator I was once told by a barrister: “You have the power to criminalise and bankrupt my client. You must use those powers carefully.”

She was of course correct. It is not a phrase I have ever forgotten and it is very useful to have in your mind when considering TE applications.

Enforcement

Failure to meet conditions on a consent or discharging without a consent is a criminal offence. If serious enough offenders can be tried in Crown Court and face unlimited fines and/or a prison sentence. The offence is one of strict liability which means that intent does not have to be demonstrated, only that the offence has been committed. In practice most breaches do not result in court appearances, SUs will try to draw up action plans or similar so that compliance can be assured. When deciding what action to take in discovering a breach the SU would normally take into account all the circumstances, for instance was the discharge serious, deliberate and repeated a single event, or an oversight which had little impact?

If a company is discovered discharging without a consent an SU would usually ensure the discharge was properly regulated going forward rather than immediately prosecute, although being a strict liability offence they could do so if the situation warranted it.

TE practitioners will normally draw up a plan of random inspection visits based on the risk the discharge represents for the SU. At these visits a sample will normally be taken which not only determines their compliance with quantitative limits on their consent but can also be used to raise charges. These visits also enable TE practitioners to cast an eye over the wider site. One eagled eye member of staff spotted that the company was using fire hydrant water to supply to their process which is unmeasured so not charged and illegal!

Charging

A significant element of TE work is the raising of charges for discharges. These charges are regulated by OFWAT and reflect the cost of transporting and treating the discharge. Different SUs vary slightly but generally the charge is related to the volume and strength using forms of the Mogden formula (so called because this method was first used at Mogden sewage works in SW London).

Most SUs calculate strength using the chemical oxygen demand and suspended solids in the discharge.

Market Separation

In 2017 competition was introduced for non-household customers (NHHC) including TE charging.

The NHHCs choose a Retailer to whom they pay charges, the Retailer then pays a wholesale bill to the SU. The principle is that the NHHC does not interact directly with Wholesaler. However, as TE is primarily a regulatory function and the consent is still a direct link between the SU (wholesaler) and NHHC, this does not fit within the wholesaler/retailer model. This leads to difficulties as there are various contradictions and tensions between the Market Codes and the law.

I hope to explain these issues and possible solutions more fully in a later article.

Finally, is it ‘Trade Effluent’ or ‘trade effluent’? I am afraid that is a mystery that has as yet not been revealed to us mere mortals.

CHANGES IN THE NEW EUROPEAN DRINKING WATER DIRECTIVE REQUIRE UPDATES IN PORTABLE WATER SENSING PLATFORMS

Hand in hand with population growth and industrialisation comes increased resource requirements, most critical in perpetuity has been safe drinkable water.

by Dr Alejandro GarciaMiranda Ferrari

Faculty of Science and Engineering, Manchester Metropolitan University and KTP Associate with Aquacheck Engineering

In early history, settlements were typically built next to water sources, later within civilised urban conurbations water was supplied from an external source using a pipe network. With one of the earliest known water networks dating by to Mesopotamian times (3000 BC). The industrial revolution further improved and complicated water supply networks with the implementation of water treatment plants. One of the major challenges for the UK in the coming century is the maintenance and improvement of the dated, malfunctioning and incredibly complicated water infrastructure found within many cities. Failing to tackle this problem will result in a wide variety of severe issues, some of which are healthrelated. Heavy metal contamination within household water supplies is a ubiquitous problem, arising from the existing water distribution networks, but also from human, industrial, mining and/ or agricultural activities. Some of the most common metal contaminants in drinking water are mercury, lead and cadmium, which are toxic to humans when entering the body in high quantities.1, 2

Heavy metal toxicity within fauna arises from their capacity to bind with certain protein sites blocking the original essential metals, bio-accumulating and becoming dangerous. In humans heavy metal poisoning is typically characterised by damage to the nervous system, hard tissue and particularly kidney and liver function.3-7

The European Union (EU) first tried to limit the harmful effect of heavy metal water contamination in 1980 with the establishment of the Water Framework Directive (WFD) by setting limits as to the acceptable concentrations of heavy metals within water supplies. The WFD was published to ensure the protection of water bodies, environmental groups, nature itself and every sector of society that uses water. Later in 2015, Drinking Water Directive (DWD) was updated to include new monitoring systems, sampling methods and parameters.

Thanks to the pressure generated by the popular ‘Right2Water’ campaign, which achieved more than 1.8 Million citizens’ signatures, in 2020 the EU has passed the latest updated of the DWD. The 2020 DWD update now specifies 48 different parameters that must be controlled by water suppliers and regulators, such as heavy metals, pesticides and microbes.8

A heavy metal contaminant that is of particular concern due to its acutely negative impact upon health is lead (Pb2+). The presence of Pb2+ within drinking water is mostly a result to its use in the plumbing/distribution system. Lead solder and fittings were standardly used until their ban in the UK in 1970, however they are still present within many plumbing systems installed before their ban. The cost to replace lead containing systems is calculated to be ca. £7 billion for British properties alone, with the global cost being a significant barrier to tackling the problem of lead within water supplies globally.9 The new Pb2+ limit in drinking water, designated by the DWD, is 5 parts per billion (ppb) rather than the previous limit of 10 ppb. EU water suppliers have the next 10 years to meet this new target.

In order for a typical water supplier to analyse the concentration of Pb2+ within the water they supply they need to send a specialist to collect a sample, which has to be transported to a centralised lab overnight where they are analysed. Unfortunately, the chemical, biological and physical composition of these samples change during transportation, handling and the analysis itself of the samples, leading to potentially mistaken results.10

The normal analytical methods that water companies undertake uses bulky, complicated and costly laboratory-based techniques to analyst the presence of heavy metals such as atomic absorption spectrometry (AAS), inductively coupled plasma (ICP)-mass spectrometry (MS), atomic emission spectrometry (AES), X-Ray fluorescence (XRF) and a variety optical techniques. The protocols for these techniques might also need pre-treatment/pre-concentration and/ or separation techniques, which need to be performed by a highly qualified technician in order to be able to perform the chosen analysis. A water company needs to analyse thousands of samples in this manner in order to build an accurate representation of the lead contamination within a specific area.

There is a clear need to develop a new generation of state-of-the-art in-situ sensors that are able to eliminate the transportation step, decrease sampling times and reduce the associated costs.

FEATURE: WATER QUALITY

Figure 1. Schematic representation of electrochemical hand-held device for lead in drinking water, developed by the KTP at Manchester Metropolitan University and Aquacheck Engineering.

This will enable an increase in the monitoring studies and tackle the heavy metal presence in our water network. Identification of areas that are likely to be most at risk of high exposure (i.e. schools and hospitals) using affordable, massproducible, in-situ and accurate methods is recognised as one of the top priorities of the water industry.

Current commercial heavy metal test kits exhibit high sensitivities, but require complex image analysis or molecular recognition probes11, 12 at high price levels. Given this, these kits are not a cost-effective solution for large scale insitu water monitoring. Electrochemistrybased methods in comparison are more suitable options for in-situ heavy metal analysis13-15, offering small and portable equipment size, low-cost, lack/easy sample preparation and the possibility of multi-elemental detection.

Manchester Metropolitan and Aquacheck Engineering currently have a Knowledge Transfer Project (KTP) developing a handheld sensor device for lead in drinking water, as depicted in Figure 1, setting the first stone in the path for a larger aim of developing a series of multielemental detection that can be performed within minutes at the client’s tap. The collaborative project between Aquacheck Engineering and Manchester Metropolitan University has recently published a tutorial review explaining the latest advances in portable sensing solutions based in electrochemical methods in the Royal Society of Chemistry (RSC) Journal “Environmental Science: Water Research & Technology”.16

The tutorial review titled “Recent advances in portable heavy metal electrochemical sensing platforms”16 comprehensively introduces and explores the current advances related to electrochemical methods, material selection and development that researchers have to consider in order to develop a portable electrochemical sensors capable of meeting the newly EU introduced legislation.

If the DWD thresholds for heavy contamination within water are to be met, it is paramount to improve our current detection techniques and transition from rather large, complicated and expensive laboratory-based methods to in-situ, miniaturised, user-friendly and less chemical reagent waste heavy metal monitoring devices.

References

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Biotechnology, 2020, 104, 907-914. 2. P. B. Tchounwou, C. G. Yedjou, A. K. Patlolla and D. J. Sutton,

Exp Suppl, 2012, 101, 133-164. 3. G. Aragay, J. Pons and A. Merkoçi, Chemical Reviews, 2011, 111, 3433-3458. 4. J. W. Hamilton, R. C. Kaltreider, O. V. Bajenova, M. A. Ihnat, J.

McCaffrey, B. W. Turpie, E. E. Rowell, J. Oh, M. J. Nemeth, C. A.

Pesce and J. P. Lariviere, Environmental health perspectives, 1998, 106 Suppl 4, 1005-1015. 5. B. L. Vallee and D. D. Ulmer, Annual review of biochemistry, 1972, 41, 91-128. 6. T. Partanen, P. Heikkila, S. Hernberg, T. Kauppinen, G. Moneta and A. Ojajarvi, Scandinavian journal of work, environment & health, 1991, 17, 231-239. 7. M. Jaishankar, T. Tseten, N. Anbalagan, B. B. Mathew and K.

N. Beeregowda, Interdisciplinary toxicology, 2014, 7, 60-72. 8. E. C. I. ECI, Right2Water, https://www.right2water.eu/, (accessed 04/02/2020). 9. S. Potter, Journal, 1997, 97. 10. Z. Zou, A. Jang, E. T. MacKnight, P. Wu, J. Do, J. S. Shim, P.

L. Bishop and C. H. Ahn, IEEE Sensors Journal, 2009, 9, 586594. 11. G. G. Morbioli, T. Mazzu-Nascimento, A. M. Stockton and E.

Carrilho, Analytica Chimica Acta, 2017, 970, 1-22. 12. N. Ullah, M. Mansha, I. Khan and A. Qurashi, TrAC Trends in

Analytical Chemistry, 2018, 100, 155-166. 13. J. Wang, in Encyclopedia of Electrochemistry, 2007, DOI: 10.1002/9783527610426.bard030203. 14. G. E. Batley, Marine Chemistry, 1983, 12, 107-117. 15. Y. Lu, X. Liang, C. Niyungeko, J. Zhou, J. Xu and G. Tian,

Talanta, 2018, 178, 324-338. 16. A. García-Miranda Ferrari, P. Carrington, S. J. Rowley-Neale and C. E. Banks, Environmental Science: Water Research &

Technology, 2020, DOI: 10.1039/D0EW00407C.