Mission critical systems, such as water purification systems, require secure and reliable data networks to ensure they perform efficiently, effectively and without interruption. At some of Anglian Water’s sites (GB), there was automation equipment that was installed over 30 years ago. This was problematic, as it did not provide suitable infrastructure for the transition to modern IP based communication networks. For example, replacing the existing programmable logic controllers (PLC), which was required, made them incompatible with the existing data networks and created the need for the entire automation system to be upgraded at the same time. A key benefit of upgrading the system would be an increase in network redundancy and consequently the reliability of their service for customers. It would also provide Anglian Water with holistic monitoring of the system and access to real time data.

In the autumn of 2019, Anglian Water wanted to upgrade the data networks for one of their sites and enlisted the help of Westermo. The network connected ten remote pumps back to a main water plant near Kings Lynn using a series of RS485 cables. One option was to simply replace the existing ageing data communications equipment with similar devices, but that would not satisfy the requirement for network redundancy and modernisation. In addition, the company wanted to use the existing cables to minimise the cost of the project and to implement a 4G network to provide communication redundancy.

Collaboration on this project started when engineers from Anglian Water attended a Westermo Certified Engineer training course to help them gain the knowledge needed to upgrade their existing data communications network. This led to the development of a network diagram to determine the full scope and significance of this specific project, and it was decided that they would get support from Westermo to design and configure the network.

Network design and installation phases
Working with Anglian Water engineers, Westermo designed a data network that utilised the existing multiplexer network and RS-485 cables to provide a backbone for Ethernet communication, and added a new 4G cellular network to provide redundancy. With this design, the network could continue to function using the 4G communications and a primary link could be added as they went, allowing commissioning, testing and firewalls to be implemented on a `per site’ basis. Once the single-pair high-speed digital subscriber line (SHDSL) was operating, the Westermo Wolverine line extenders would automatically reconfigure the network to operate via the SHDSL.

The importance of this project was evident throughout the design phase due to it supporting a live, mission critical system. The solution needed to be implemented within a tight schedule and start immediately without any issues. Collaboration was key to properly understand the network requirements. Most importantly, the remote pumping stations needed to remain fully operational during commissioning.

The network is constructed predominantly of Westermo WeOS devices, which are using the non-propriety open shortest path first (OSPF) routing protocol and support virtual private networks (VPN). OSPF provides a mechanism to select different paths for network traffic and the VPN provides an added layer of security for the network. This complex setup required a clear understanding of the network structure to determine how the data will be routed should there be a failure at any point on the SHDSL.

To help the customer commission the network, Westermo provided supporting documentation, which was produced using Westermo’s WeConfig software configuration tool. The report function of the software pulled together the whole network to present a clear overview, providing confidence during testing and commissioning stages. WeConfig also allowed a full backup of the whole site in one sweep, and a detailed overview of physical connections.

Each site required Anglian Water to install new external antennas to provide them with suitable 4G coverage. Once the 4G network was available and operating, this allowed the twisted pair cables to be updated one at a time. Once the SHDSL links were commissioned, the network could reroute traffic, via the SHDSL backbone to Anglian Water’s central site.

Unexpected circumstances during commissioning
The 4G network was included in the plan simply to provide redundancy, but it offered an unexpected benefit. During commissioning of the network, the global COVID-19 pandemic hit the world. This made it very difficult for support personnel to go on-site safely and accelerated the need for remote management to monitor the sites.

Fortunately, the new network was designed and configured to enable remote access, using the 4G communications. Originally this was to support network management tasks, but this also provided a method for engineers to remotely connect to the network from within the Anglian Water system to assist with any technical issues during and after the network was configured. Westermo technical engineers were able to provide support to the customer, via this method, ensuring the network was up and running and all members of staff involved were safe.

Foto Jonas Bilberg

Monitoring the System
In addition to designing the network and configuring the network devices, Westermo also configured the ability to monitor the 4G communications and SHDSL port status using Simple Network Management Protocol (SNMP). By monitoring the network, Anglian Water could determine if the connection was using the primary Ethernet backbone or 4G cellular network. This helps them understand if a fault has occurred on one of the SHDSL lines.

Additional support
Once the network was in place and operating, firewalls were added. Due to the pandemic, it was not possible to have support on-site when adding the firewalls, which meant remote support was the only option. Every firewall modification had to be carefully planned to ensure that support engineers were not locked out during testing. Configuration of the firewalls was performed using commands via the 4G communications. Configurations of the firewalls was completed at the central site first to ensure that communication to all of the remote sites was working correctly, before rolling out a full secure network. The remote sites were then added one at a time to reduce risk. Implementing the firewalls was challenging both for Anglian Water and Westermo, with every command needing to be accurate. Ultimately, configuration of the firewalls was successful and going forward has provided the customer confidence that the network is secure.

“We felt fully supported by Westermo throughout design and installation. We are delighted we now have an upgraded, supportable system in place and that this was achieved during extremely challenging times. Collaboration between all parties has made this a success”, explained Charlie Pritchard, Infrastructure Project Manager at Anglian Water.

Products used in application
In total, twelve Wolverine DDW-142 and DDW-225 line extenders were installed to enable the existing cables to be reused to create effective Ethernet networks over long distances to the remote sites. The Wolverines use SHDSL technology, which makes it possible to reuse many types of pre-existing copper cables which can lead to considerable financial savings. All Wolverine devices are powered by Westermo’s WeOS operating system, which enables complex networking functions to be configured easily.

MRD-455

Ten of Westermo’s MRD-455 routers were installed, one at each site, to create the 4G network. As well as forming the 4G network, the cellular routers provide a gateway to the IP network, and a unique method for port forwarding to allow remote support and monitoring. A Westermo RedFox RFI-211-T3G industrial routing switch was installed at the central site, providing the necessary layer 3 functionality required for this type of application. All the Westermo devices were delivered pre-configured to save time and reduce project risk.

Result
Once installed, the network immediately operated correctly, which can be attributed to the careful planning and collaboration between Anglian Water and Westermo. Despite the challenges caused by the COVID-19 pandemic, Westermo was able to develop a stable, secure and ultra-robust network with remote access support as an alternative to on-site support. This has ensured the network has operated smoothly without any interruptions. As a result of this successful network upgrade, the local area can continue to enjoy clean and uninterrupted water supply every day.

Matt Dibbs, Managing Director Meteor Communications Ltd., explains how the Coronavirus pandemic presented significant challenges to the collection of environmental data. However, by utilising novel technology, British water companies and the Environment Agency have been able to continue gathering water quality data in locations from Cornwall to Cumbria. Matt believes that this provides a template for environmental monitoring on the future.

The Coronavirus pandemic presented significant challenges to the collection of environmental data. However, by utilising novel technology, water companies and the Environment Agency have been able to continue gathering key data in locations from Cornwall to Cumbria.

Water quality monitoring
The British Environment Agency and water utilities have statutory obligations to protect and enhance water resources; and in order to fulfil these obligations they undertake large numbers of measurements to establish baseline data, detect trends, monitor mitigation measures, and identify sources of pollution from both point and diffuse sources. This involves making a range of measurements; either collecting samples for laboratory analysis or employing portable instruments in the field. To support these activities, rapidly deployable, automatic, remote monitoring systems have also been developed to provide real-time access to data 24/7.

The Environment Agency’s Environmental Sensor Network (ESNET) is operated by the National Laboratory Service. This agile monitoring capability of over 150 sites is providing a template for sustainable, resilient, environmental monitoring. ESNET is comprised of modular water quality monitoring systems that can be quickly and easily deployed at remote sites. The telemetry modules and website capability are developed and supplied by Meteor Communications Ltd.

The laboratory analysis of samples is vitally important and allows industry and regulators to analyse for an extensive array of parameters. These samples inform a better understanding of longer term trends and facilitate the monitoring of trace and emerging pollutants. However, water bodies are highly dynamic environments. Precipitation, flow and the intermittent or diurnal nature of process and agricultural effluents mean that in some circumstances it is necessary to employ enhanced high-resolution monitoring techniques to provide evidence upon which informed operational and policy decisions can be made.

Real-time, high-resolution water quality monitoring systems
The Environment Agency uses two main types of continuous water quality monitors; a fixed, cabinet or kiosk based system (right), and a portable version which is housed in a rugged case (below). Evidence from these systems is utilised by environment planners, ecologists, fisheries and environment management teams across the agency. These continuous water quality monitoring systems have been developed and refined over the last 20 years, so that they can be quickly and easily deployed at almost any national location; delivering data via telemetry within minutes of installation. This high-intensity monitoring capability substantially improves the temporal and spatial quality of data. The rapid deployment of these monitors now enables the agency to respond more quickly to pollution events.

Each system is built around a battery-powered multi-parameter water quality sonde; situated in the river or located in a bankside flow-through chamber, with samples being taken at 15 minute intervals. Typically, the sondes are loaded with sensors for measuring parameters such as dissolved oxygen, temperature, pH, conductivity, turbidity, ammonium, Blue Green Algae and chlorophyll. Additionally, the systems can incorporate an automatic sampler which can be triggered when pre-determined conditions arise. This means that event-triggered samples can be made available for subsequent laboratory investigation.

Measured data is transferred securely to the Meteor Data Cloud, where stakeholders access graphical, tabular and geospatial views to see live readings and retrieve recorded data. With this customisable data presentation, managers are able to communicate evidence in a form which is more accessible and meaningful to public representatives, interest groups and stakeholders. This also enables bodies such as the Environment Agency to promote the use of open data, providing live data links, advice and services to a diverse range of public groups and organisations such as flood awareness groups, rivers trusts and angling organisations.

During the coronavirus pandemic the Environment Agency collected over 16,000 samples per day using ESNET and the cloud-based viewer was made available to all water quality practitioners across the Defra family, as well as a wide range of external bodies.

The advantages of remote monitoring networks
By collecting data automatically; the volume of evidence increases dramatically, furthermore, such systems are resilient to the effects of issues such as a lockdown; because monitoring practitioners are able to collect and assess data; even if they are isolated at home.

In recent years, sensors and water quality sondes have undergone significant development to improve reliability and extend the period between service and calibration. Meteor Communications provides a comprehensive maintenance program for customers on a monthly basis and freshly calibrated units are constantly in circulation within the ESNET system.

Continuous monitoring enables the detection of transient spikes that can arise from pollution incidents; helping to raise timely alarms and identify ongoing sources of pollution. This evidence can be used to develop informed interventions by stakeholders in industry and agriculture, and to enable the adoption of practices that improve water quality.

Integrated systems such as those operated in the Thames Valley catchment are able to track pollution events as they move with the river, which means for example, that water treatment plants can adjust their intakes accordingly.

Tidal water presents a major monitoring challenge because large volumes of saline water are constantly moving back and forth, which significantly complicates the comparison of measurements at one point on the river. So, for example, a measurement at one location at 9am is not directly comparable with another measurement at 9am a week later, because one might be taken at low tide and the other at high tide. The transient effects of CSO’s and algal activity further complicate the picture. Water quality scientists at the Environment Agency have therefore worked closely with Meteor Communications to develop a software-based monitoring system, known as ‘Half Tide Correction’ (HTC). In simple terms, this corrects for the effects of the tide and allows assessment of the underlying water quality.

Continuous, accurate and robust data allows managers to assess the impact of developments and remediation measures. Good data, used as evidence, informs the evaluation of investments and leads to better decision making.

The ESNET network also provides image acquisition, and the Environment Agency and others have deployed over 600 ESNET camera sites. These remote cameras are used to continuously monitor a wide range of flood defence infrastructure and assets; rapidly detecting blockages or overflows and avoiding the need for unnecessary and costly site visits.

ESNET systems also provide an essential tool for measuring the effectiveness of Natural Flood Management (NFM) schemes. In Oxfordshire for example, working with a wide range of partners in the Evenlode catchment, the systems are helping to evaluate the effectiveness of NFM measures for the local community and other stakeholders.

Utilities – final effluent monitoring
The flexibility of the ESNET systems makes them ideal for monitoring water quality at waste water treatment works. The responsibility for monitoring discharges rests with the operators themselves under the terms of operator self-monitoring (OSM) agreements. OSM is now delivered by a spot sampling regime supported by real time monitors, so an opportunity exists for all stakeholders to benefit from the advantages of continuous monitoring.

A British water company is now operating 130 ESNET final effluent monitoring systems across their business. These sites have continued to operate during the COVID-19 lockdown providing operators and managers with vital data with which to assess performance and compliance during this challenging period.

Summary
Recent advances in technology have enabled the development of continuous monitoring systems that are quick and easy to install. The portable ESNET system is routinely commissioned in less than an hour, and the pumped kiosks can usually be installed within half a day.

With little or no capital works necessary prior to the installation of an ESNET system, continuous, easily accessible, multi-parameter data can be established quickly and cost effectively. Real-time monitoring means less travel, less time on site and a lower carbon footprint. Real time data can also be provided to stakeholders, timely alarms triggered and monitoring can continue unaffected by the impact of viral pandemics.

@MeteorComms @_Enviro_News #PAuto #Water #coróinvíreas #COVID19 #coronavirus

Monitoring is an essential component of natural flooding management, helping to define appropriate measures, measure their success, keep stakeholders informed, identify mistakes, raise alarms when necessary, inform adaptive management and help guide future research.

Great Fen showing Holme Fen woods top left and new ponds and meres in April

Flooding is a natural process, but it endangers lives and causes heavy economic loss. Furthermore, flood risk is expected to increase with climate change and increased urbanisation, so a heavy responsibility lies with those that allocate funding and formulate flood management strategy. In the following article, Nigel Grimsley from OTT Hydromet explains how the success of such plans (both the design and implementation) depend on the accuracy and reliability of the monitoring data upon which they rely.

Climate projections for Britain suggest that rainfall will increase in winter and decrease in summer, and that individual rainfall events may increase in intensity, especially in winter. This paradigm predicates an increased risk of flooding.

Emphasising the urgent need for action on flood risk, (British) Environment Agency chairwoman Emma Howard Boyd, has said that on current trends, global temperature could rise between 2 deg C and 4 Deg C by 2100 and some communities may even need to move because of the risk of floods. Launching a consultation on the agency’s flood strategy, she said: “We can’t win a war against water by building away climate change with infinitely high flood defences.”

In response, Mike Childs, head of science at Friends of the Earth, said: “Smarter adaptation and resilience building – including natural flood management measures like tree-planting – is undeniably important but the focus must first and foremost be on slashing emissions so that we can avoid the worst consequences of climate chaos in the first place.”

Historically, floodplains have been exploited for agricultural and urban development, which has increased the exposure of people, property and other infrastructure to floods. Flood risk management therefore focused on measures to protect communities and industry in affected areas. However, flood risk is now addressed on a wider catchment scale so that initiatives in one part of a catchment do not have negative effects further downstream. This catchment based approach is embodied within the EU Floods Directive 2007/60/EC, and in recent years, those responsible for flood management have increasingly looked for solutions that employ techniques which work with natural hydrological and morphological processes, features and characteristics to manage the sources and pathways of flood waters. These techniques are known as natural flood management (NFM) and include the restoration, enhancement and alteration of natural features but exclude traditional flood defence engineering that effectively disrupts these natural processes.

NFM seeks to create efficiency and sustainability in the way the environment is managed by recognising that when land and water are managed together at the catchment scale it is possible to generate whole catchment improvements with multiple benefits.

Almost all NFM techniques aim to slow the flow of water and whilst closely connected, can be broadly categorised as infiltration, conveyance and storage.

Infiltration
Land use changes such as set-aside, switching arable to grassland or restricted hillside cropping, can improve infiltration and increase water retention. In addition, direct drilling, ‘no-till’ techniques and cross slope ploughing can have a similar effect. These land use techniques are designed to reduce the soil compaction which increases run-off. Livestock practices such as lower stocking rates and shorter grazing seasons can also help. Field drainage can be designed to increase storage and reduce impermeability, which is also aided by low ground pressure vehicles. The planting of shrubs and trees also helps infiltration and retention by generating a demand for soil moisture, so that soils have a greater capacity to absorb water. Plants also help to bind soil particles, resulting in less erosion – the cause of fertility loss and sedimentation in streams and rivers.

Conveyance
Ditches and moorland grips can be blocked to reduce conveyance, and river profiles can be restored to slow the flow. In the past, peats and bogs have been drained to increase cropping areas, but this damages peatlands and reduces their capacity to retain water and store carbon. The restoration of peatland therefore relies on techniques to restore moisture levels. Pumping and drainage regimes can be modified, and landowners can create strategically positioned hedges, shelter belts and buffer strips to reduce water conveyance.

Storage
Rivers can be reconnected with restored floodplains and river re-profiling, leaky dams, channel works and riparian improvements can all contribute to improved storage capability. In urban areas permeable surfaces and underground storage can be implemented, and washlands and retention ponds can be created in all areas. As mentioned above, the re-wetting of peatland and bogs helps to increase storage capacity.

Many of the effects of NFM might be achieved with the re-introduction of beavers, which build dams that reduce peak flows, create pools and saturate soil above their dams. The dams also help to remove pollutants such as phosphates. Beavers do not eat fish, instead preferring aquatic plants, grasses and shrubs during the summer and woody plants in winter. Beavers are now being introduced in a number of areas in trials to determine their value in the implementation of NFM. One of the key benefits offered by beavers is their ability to quickly repair and rebuild dams that are damaged during extreme weather. However, whilst the potential benefits of beavers are well known, several groups have expressed concern with the prospect of their widespread introduction. For example, farmers and landowners may find increased areas of waterlogged land due to blocked drainage channels. In addition, dams present a threat to migratory fish such as salmon and sea trout.

Beavers are native to Britain and used to be widespread, but they were hunted to extinction during the 17th century. However, other non-native species such as signal crayfish can have a detrimental effect on flood protection because they burrow into river banks causing erosion, bank collapse and sediment pollution. Signal crayfish are bigger, grow faster, reproduce more quickly and tolerate a wider range of conditions than the native white-clawed crayfish. Signal crayfish are also voracious predators, feeding on fish, frogs, invertebrates and plants, and as such can create significant negative ecological effects.

NFM benefits
NFM provides protection for smaller flood events, reduces peak flooding and delays the arrival of the flood peak downstream. However, it does not mitigate the risk from extreme flood events. Effective flood management strategy therefore tends to combine NFM with hard engineering measures. Nevertheless, NFM generally provides a broader spectrum of other benefits.

The creation of new woodlands and wetlands produces biodiverse habitats with greater flood storage capacity. They also enable more species to move between habitats. NFM measures that reduce soil erosion, run-off and sedimentation also help to improve water quality and thereby also improve habitats. In particular, these measures lower nutrient and sediment loading lower in the catchment; two issues which can have dramatic effects on water quality and amenity.

Land use and land management measures help to reduce the loss of topsoil and nutrients. This improves agricultural productivity and lowers the cost of fertilizers. Furthermore, a wide range of grants are available for NFM measures, such as the creation of green spaces and floodplains, to make them more financially attractive to farmers and landowners.

Many NFM measures help in the fight against climate change. For example, wetlands and woodlands are effective at storing carbon and removing carbon dioxide from the atmosphere. Measures that reduce surface run off and soil erosion, such as contour cultivation, can also reduce carbon loss from soil.

Monitoring NFM
Given the wide range of potential NFM benefits outlined above, the number and type of parameters to be monitored are likely to be equally diverse. Baseline data is essential if the impacts of implemented measures are to be assessed, but this may not always be deliverable. For example, it may only be possible to collect one season of data prior to a five year project. However, it may be possible to secure baseline data from other parties. In all instances data should of course be accurate, reliable, relevant and comparable.

Monitoring data should be used to inform the design of NFMs. For example, a detailed understanding of the ecology, geomorphology, hydrology and meteorology of the entire catchment will help to ensure that the correct measures are chosen. These measures should be selected in partnership with all stakeholders, and ongoing monitoring should provide visibility of the effects of NFM measures. Typically stakeholders will include funders, project partners, local communities, landowners, regulators and local authorities.

Since NFM measures are designed to benefit an entire catchment, it is important that monitoring is also catchment-wide. However, this is likely to be a large area so there will be financial implications, particularly for work that is labour-intensive. Consequently, it will be necessary to prioritise monitoring tasks and to deploy remote, automatic technology wherever it is cost-effective.

OTT ecoN Sensor

Clearly, key parameters such as rainfall, groundwater level, river level and surface water quality should be monitored continuously in multiple locations if the benefits of NFM are to be measured effectively. It is fortunate therefore that all of these measurements can be taken continuously 24/7 by instruments that can be left to monitor in remote locations without a requirement for frequent visits to calibrate, service or change power supplies. As a business OTT Hydromet has been focused on the development of this capability for many years, developing sensors that are sufficiently rugged to operate in potentially aggressive environments, data loggers with enormous capacity but with very low power requirement, and advanced communications technologies so that field data can be instantly viewed by all stakeholders.

Recent developments in data management have led to the development of web-enabled data management solutions such as Hydromet Cloud, which, via a website and App, delivers the backend infrastructure to receive, decode, process, display and store measurement data from nearly any remote hydromet monitoring station or sensor via a cloud-based data hosting platform. As a consequence, alarms can be raised automatically, which facilitates integration with hard engineering flood control measures. Hydromet Cloud also provides access to both current and historic measurement data, enabling stakeholders to view the status of an entire catchment on one screen.

Holme Fen – a monitoring lesson from the 1850s

Holme Fen post

Surrounded by prime agricultural land to the south of Peterborough (Cambridgeshire,GB) , the fens originally contained many shallow lakes, of which Whittlesey Mere was the largest, covering around 750 hectares in the summer and around twice that in the winter. Fed by the River Nene, the mere was very shallow and was the last of the ‘great meres’ to be drained and thereby converted to cultivatable land.

Led by William Wells, a group of local landowners funded and arranged the drainage project, which involved the development of a newly invented steam powered centrifugal pump which was capable of raising over 100 tons of water per minute by 2 or 3 feet. A new main drain was constructed to take water to the Wash. Conscious of the likely shrinking effect of drainage on the peaty soil, Wells instigated the burial of a measurement post, which was anchored in the Oxford Clay bedrock and cut off at the soil surface. In 1851 the original timber post was replaced by a cast iron column which is believed to have come from the Crystal Palace in London.

By installing a measurement post, Wells demonstrated remarkable foresight. As the drainage proceeded, the ground level sank considerably; by 1.44 metres in the first 12 years, and by about 3 metres in the first 40 years. Today, around 4 metres of the post is showing above ground, recording the ground subsidence since 1852. The ground level at Holme Post is now 2.75 metres below sea level – the lowest land point in Great Britain.
Several complications have arisen as a result of the drainage. Firstly, there has been a huge impact in local ecology and biodiversity with the loss of a large area of wetland. Also, as the ground level subsided it became less sustainable to pump water up into the main drain.

Holme Fen is now a National Nature Reserve, managed by Natural England, as is the nearby Woodwalton Fen. They are both part of the Great Fen Project, an exciting habitat restoration project, involving several partners, including the local Wildlife Trust, Natural England and the Environment Agency. At Woodwalton, the more frequent extreme weather events that occur because of climate change result in flooding that spills into the reserve. In the past, this was a good example of NFM as the reserve provided a buffer for excess floodwater. However, Great Fen Monitoring and Research Officer Henry Stanier says: “Floodwater increasingly contains high levels of nutrients and silt which can harm the reserve’s ecology, so a holistic, future-proof strategy for the area is necessary.”

Applauding the farsightedness of William Wells, Henry says: “As a conservationist I am often called in to set up monitoring after ecological recovery has begun, rather than during or even before harm has taken place. At the Wildlife Trust, we are therefore following the example provided by Wells, and have a network of monitoring wells in place so that we can monitor the effects of any future changes in land management.

“For example, we are setting up a grant funded project to identify the most appropriate crops for this area; now and in the future, and we are working with OTT to develop a monitoring strategy that will integrate well monitoring with the measurement of nutrients such as phosphate and nitrate in surface waters.”

Summary
Monitoring provides an opportunity to measure the effects of initiatives and mitigation measures. It also enables the identification of trends so that timely measures can be undertaken before challenges become problems, and problems become catastrophes.

Monitoring is an essential component of NFM, helping to define appropriate measures, measure their success, keep stakeholders informed, identify mistakes, raise alarms when necessary, inform adaptive management and help guide future research.

#Environment @OTTHydromet @EnvAgency @friends_earth

Methods for checking water quality are an incredibly important part of the many processes involved in ensuring we have access to safe drinking water. However, as contaminants can come from many different sources, finding a general solution for contaminant identification and removal can be difficult.

Purification processes for water treatment include removal of undesirable chemicals, bacteria, solid waste and gases and can be very costly. Utility companies in England and Wales invested £2.1 billion (€2.44b) between 2013 and 2014 into infrastructure and assorted costs to ensure safe drinking water.¹

One of the most widely used measures for assessing whether water is safe for consumption or not is the analysis of the organic carbon (TOC) content. Dissolved organic carbon content is a measure of how much carbon is found in the water as part of organic compounds, as opposed to inorganic sources such as carbon dioxide and carbonic acid salts.²   It has been a popular approach since the 1970s for both assessment of drinking water and checking wastewater has been sufficiently purified.

The proportion of organic carbon in water is a good proxy for water quality as high organic carbon levels indicate a high level of organisms in the water or, contamination by organic compounds such as herbicides and insecticides. High levels of microorganisms can arise for a variety of reasons but are often a sign of contamination from a wastewater source.

Testing TOC
Water therefore needs to be continually monitored for signs of change in the TOC content to check it is safe for consumption. While many countries do not specifically regulate for TOC levels, the concentrations of specific volatile organic compounds are covered by legislation and recommended levels of TOC are 0.05 ml/l or less.³

There are a variety of approaches for testing water for organic carbon. One approach is to measure the entire carbon content (organic and inorganic) and then subtract any carbon dioxide detected (as it is considered inorganic carbon) and any other carbon from inorganic sources. Another is to use chemical oxidation or even high temperature so that all the organic compounds in the sample will be oxidized to carbon dioxide, and measuring the carbon dioxide levels, therefore, acts as a proxy for the TOC concentration.

For wastewater plants, being able to perform online, real-time analysis of water content is key and measurements must be sensitive and accurate enough to pick up small changes in even low concentrations of chemical species. British legislation also makes it an offense to supply drinking water which does not adhere to legislation⁴, with several water suppliers being fined over a hundred million pounds for recent discharges of contaminated waters.⁵

Vigilant Monitors
One of the advantages of using carbon dioxide levels as a proxy for TOC content is that carbon dioxide absorbs infrared light very strongly. This means using nondispersive infrared (NDIR) detectors provide a very sensitive way of detecting even trace amounts of carbon dioxide.

Edinburgh Sensors are one of the world leaders in NDIR sensor production and offer a range of NDIR-based gas detectors suitable for TOC measurements of water.⁶ Of these, for easy, quick and reliable TOC measurements, the Gascard NG is an excellent device for quantifying carbon dioxide levels.⁷

Gascard NG
The Gascard NG is well-suited to continual carbon dioxide monitoring for several reasons. First, the device is capable of detecting a wide range of carbon dioxide concentrations, from 0 – 5000 ppm, maintaining a ± 2 % accuracy over the full detection range. This is important so that the sensor has the sensitivity required for checking TOC levels are sufficiently low to be safe for drinking water but means it is also capable of operating under conditions where TOC levels may be very high, for example in the wastewater purification process.

As it can come with built-in true RS232 communications for both control and data logging, the Gascard NG can be used to constantly monitor carbon dioxide levels as well as be integrated into feedback systems, such as for water purification, to change treatment approaches if the TOC content gets too high. UK legislation also requires some level of record-keeping for water quality levels, which can also be automated in a straightforward way with the Gascard.4

The Gascard NG is capable of self-correcting measurements over a range of humidity conditions (0 – 95 %) and the readings can be pressure-corrected with on-board electronics between 800 to 1150 mbar. Temperature compensation is also featured between 0 to 45ºC to ensure reliable measurements, over a wide range of environmental conditions.

Designed to be robust, maintenance-free and fail-safe, the Gascard NG also comes with several customizable options. The expansion port can be used for small graphical display modules for in-situ observable readings and TCP/IP communications can also be included if it’s necessary to have communications over standard networks. In conjunction with Edinburgh Sensor’s expertise and pre- and post-sales support, this means that the Gascard NG can easily be integrated into existing TOC measurement systems to ensure fast and accurate monitoring at all times.

NOTES

1. Water and Treated Water (2019),
2. Volk, C., Wood, L., Johnson, B., Robinson, J., Zhu, H. W., & Kaplan, L. (2002). Monitoring dissolved organic carbon in surface and drinking waters. Journal of Environmental Monitoring, 4(1), 43–47.
3. DEFRA (2019)
4. Water Legislation (2019),
5. Water Companies Watchdog (2019)
6. Edinburgh Sensors (2019),
7. Gascard NG, (2019),

#Pauto @Edinst

The processing of clean and safe drinking water is an international issue. Estimates suggest that, if no further improvements are made to the availability of safe water sources, over 135 million people will die from potentially preventable diseases by 2020.¹

Even within Britain, water purification and treatment is big business, with £2.1 billion (€2.37b 28/8/2019) being invested by utilities in England and Wales between 2013 and 2014.² Water purification consists of removing undesirable chemicals, bacteria, solids and gases from water, so that it is safe to drink and use. The standard of purified water varies depending on the intended purpose of the water, for example, water used for fine chemical synthesis may need to be ‘cleaner’ i.e. have fewer chemicals present, than is tolerable for drinking water, the most common use of purified water.

Purification Process
The process of water purification involves many different steps. The first step, once the water has been piped to the purification plant, is filtering to remove any large debris and solids. There also needs to be an assessment of how dirty the water is to design the purification strategy. Some pretreatment may also occur using carbon dioxide to change pH levels and clean up the wastewater to some extent. Here, gas monitors are used to ensure the correct gas levels are being added to the water and unsafe levels of the gas do not build up.

The following steps include chemical treatment, an filtration to remove dissolved ionic compounds.³ Then, disinfection can occur to kill any remaining bacteria or viruses, with additional chemicals being added to provide longer lasting protection.⁴ At all stages, the water quality must be constantly monitored. This is to ensure that any pollutants have been adequately removed and the water is safe for its intended purpose.

In-line gas monitors are often used as part of the water treatment process as a way of monitoring total organic carbon (TOC) content. Carbon content in water can arise from a variety of sources, including bacteria, plastics or sediments that have not been successfully removed by the filtration process.⁵ TOC is a useful proxy for water cleanliness as it covers contamination from a variety of different sources.

To use non-dispersive infrared (NDIR) gas monitors to analyze the TOC content of water, a few extra chemical reactions and vaporization need to be performed to cause the release of CO2 gas. The resulting concentration of gas can then be used as a proxy of TOC levels.⁶ This then provides a metric than can be used to determine whether additional purification is required or that the water is safe for use.

Need for Gas Monitors
NDIR gas sensors can be used as both a safety device in the water purification process as carbon dioxide, methane, and carbon monoxide are some of the key gases produced during the treatment process. ⁵ The other key use is for analysis of TOC content as a way of checking for water purity.⁷ NDIR sensors are particularly well suited for TOC analysis as carbon dioxide absorbs infrared light very strongly. This means that even very low carbon dioxide concentrations can be detected easily, making it a highly sensitive measurement approach.⁶ Other hydrocarbon gases can also easily be detected in this way, making NDIR sensors a highly flexible, adaptable approach to monitoring TOC and dissolved gas content in water.

Sensor Solutions
The need for constant gas monitoring to guide and refine the purification process during wastewater treatment means water purification plants need permanent, easy to install sensors that are capable of continual online monitoring. One of the most effective ways of doing this is having OEM sensors that can be integrated into existing water testing equipment to also provide information on water purity.

These reasons are why Edinburgh Sensors range of nondispersive infrared (NDIR) gas sensors are the perfect solution for water purification plants. NDIR sensors are highly robust with excellent sensitivity and accuracy across a range of gas concentrations. Two of the sensors they offer, the Gascard NG⁸ and the Guardian NG⁹ are suitable for detecting carbon monoxide, carbon dioxide or other hydrocarbon gases. If just carbon dioxide is of interest, then Edinburgh Sensors offers are more extensive range of monitors, including the Gascheck¹⁰ and the IRgaskiT.¹¹

The advantage of NDIR detection for these gases are the device initial warm-up times are less than 1 minute, in the case of the Guardian NG. It is also capable of 0 – 100 % measurements such gases with a response time of less than 30 seconds from the sample inlet. The readout is ± 2 % accurate and all these sensors maintain this accuracy over even challenging environmental conditions of 0 – 95 % humidity, with self-compensating readout.

The Guardian NG comes with its own readout and menu display for ease of use and simply requires a reference gas and power supply to get running. For water purification purposes, the Gascard is particularly popular as the card-based device is easy to integrate into existing water testing equipment so testing of gases can occur while checking purity. .
Edinburgh Sensors also offers custom gas sensing solutions and their full technical support throughout the sales, installation and maintenance process.

References
1. Gleick, P. H. (2002). Dirty Water: Estimated Deaths from Water-Related Diseases 2000-2020 Pacific. Pacific Institute Researc Report, 1–12.

2. Water and Treated Water (2019), https://www.gov.uk/government/publications/water-and-treated-water/water-and-treated-water

3. Pangarkar, B. L., Deshmukh, S. K., Sapkal, V. S., & Sapkal, R. S. (2016). Review of membrane distillation process for water purification. Desalination and Water Treatment, 57(7), 2959–2981. https://doi.org/10.1080/19443994.2014.985728

4. Hijnen, W. A. M., Beerendonk, E. F., & Medema, G. J. (2006). Inactivation credit of UV radiation for viruses, bacteria and protozoan (oo)cysts in water: A review. Water Research, 40(1), 3–22. https://doi.org/10.1016/j.watres.2005.10.030

5. McCarty, P. L., & Smith, D. P. (1986). Anaerobic wastewater treatment. Environmental Science and Technology, 20(12), 1200–1206. https://doi.org/10.1021/es00154a002

6. Scott, J. P., & Ollis, D. F. (1995). Integration of chemical and biological oxidation processes for water treatment: Review and recommendations. Environmental Progress, 14(2), 88–103. https://doi.org/10.1002/ep.670140212

7. Florescu, D., Iordache, A. M., Costinel, D., Horj, E., Ionete, R. E., & Culea, M. (2013). Validation procedure for assessing the total organic carbon in water samples. Romanian Reports of Physics, 58(1–2), 211–219.

8. Gascard NG, (2019), https://edinburghsensors.com/products/oem/gascard-ng/

9. Guardian NG (2019) https://edinburghsensors.com/products/gas-monitors/guardian-ng/

10. Gascheck (2019), https://edinburghsensors.com/products/oem/gascheck/

11. IRgaskiT (2019), https://edinburghsensors.com/products/oem-co2-sensor/irgaskit/

12. Boxed GasCard (2019) https://edinburghsensors.com/products/oem/boxed-gascard/

#Pauto @Edinst

Scientists from the University of Portsmouth have been investigating nutrient concentrations in the Upper River Itchen, in Hampshire (GB), on behalf of Salmon & Trout Conservation (S&TC) to better understand where phosphorus is coming from and how it is impacting river ecology.

The work has been ongoing for over three years and Lauren Mattingley, Science Officer for S&TC says: “Continuous monitoring of phosphorus has improved our understanding of nutrient dynamics in the Itchen. So far, the results from this monitoring have influenced the lowering of discharge limits from watercress companies and trout breeding farms.

“The behaviour of phosphorus in our rivers is relatively poorly understood, and this is often reflected in water quality standards that, in our opinion, lack the scientific evidence to adequately protect the ecology of the UK’s diverse water resources. Research like that which we have commissioned on the Itchen is essential to set informed phosphorus permits to protect our water life.”

Background
The Itchen is a world famous chalk stream; renowned for its fly fishing and clear water. Designated a ‘Special Area of Conservation’ (SAC) the river supports populations of water-crowfoot, Southern damselfly, Bullhead, Brook lamprey, White-clawed crayfish and otters. The upper river does not suffer from wastewater treatment plant discharges, but does support two watercress farms, which have been the focus of initiatives to reduce phosphate concentrations.

S&TC is the only British charity campaigning for wild fish and their habitats. The organisation’s goal is for British waters to support abundant and sustainable populations of wild fish and all other water-dependent wildlife. Within its ‘Living Rivers’ campaign S&TC is seeking to tackle two of the major causes of poor water quality – fine sediment and phosphorus. The Itchen is therefore being treated as a pilot river for their water quality monitoring initiatives.

Phosphorus in fresh water is a major concern globally; mainly because of its role in the formation of algal blooms and eutrophication, which have a harmful effect on water quality and habitats. Under certain conditions, raised phosphate concentrations contribute to the proliferation of nuisance phytoplankton as well as epiphytic and benthic algae. Diffuse sources of phosphate include storm water and agricultural run-off from land, and point sources include septic tanks and wastewater discharges from industry and sewage treatment works. While soluble reactive phosphorus (SRP) is the main concern, because of its availability for aquatic organism growth, other forms of phosphate such as particulate phosphate can contribute to nutrient enrichment.

From River Itchen Data File (Environment Agency)

Efforts to improve the quality of water bodies in Britain have been underway for many years. The EU’s Water Framework Directive (WFD) required Britain to achieve ‘good status’ of all water bodies (including rivers, streams, lakes, estuaries, coastal waters and groundwater) by 2015, but in 2012 only 36% of water bodies were classified as ‘good’ or better.

In 2013 the UK Technical Advisory Group (UKTAG) published recommendations to revise the standards for phosphorus in rivers, because the standards set in 2009 were not sufficiently stringent – in 75% of rivers with clear ecological impacts of nutrient enrichment, the existing standards produced phosphorus classifications of good or even high status! DEFRA (British Government Department looking after environmental matters), therefore, revised the phosphorus standards to lower concentrations. However, the SRP concentration limits vary widely according to the location and alkalinity of the river.

Recognising a gap in the understanding of the relationship between phosphorus and aquatic ecology, S&TC has a unique agreement with the Environment Agency (EA) in Hampshire in which key environmental targets have been established for the Rivers Test and Itchen to help drive ecological improvements. The agreed targets are set around the number of key water insects that should be expected in a 3-minute kick-sweep sample. The targets are for the middle and lower reaches of the catchment to support at least 10 separate mayfly species and 500 freshwater shrimps (Gammarus) – all of which are susceptible to different forms of pollution so their presence provides an effective measure of the environmental health of the river.

S&TC has also conducted research investigating the effects of fine sediment and SRP on the hatching of the blue winged olive, Serratella ignita (Ephemerellidae: Ephemeroptera) a crucial component of the aquatic food chain. The results found that a cocktail of SRP and fine sediment at concentrations exceeding those found in many UK rivers (25 mg/L fine sediment and 0.07 mg/L phosphate) caused 80% of the eggs in the experiment to die. This work was unique because it showed environmental damage caused by phosphorus beyond eutrophication.

River Itchen sampling and analysis
Five automatic water samplers have been strategically located on the river each collecting daily samples. This generates 120 samples per 24 day cycle, which are collected and transferred to the laboratory in Portsmouth. The samples are split into three for the analysis of Total Phosphate, Soluble Reactive Phosphate (SRP) and Total Dissolved Phosphate (TDP). To cope with such a high volume of work, the laboratory in the University of Portsmouth’s School of Earth & Environmental Sciences employs a QuAAtro 5-channel segmented flow autoanalyzer, from SEAL Analytical.

“The QuAAtro has been in heavy use for over 9 years,” says Senior Scientific Officer Dr Adil Bakir. “It has been employed on a number of academic and commercial research projects, and is also used for teaching purposes. As a 5-channel instrument, we are able to study phosphate, nitrate, nitrite, ammonia and silicate, but our work on the River Itchen is focused on the different forms of phosphate.”

The University of Portsmouth’s Environmental Chemistry Analytical Laboratory provides analytical and consultancy services for businesses, universities and other organisations. Dr Bakir says: “Using the QuaAAttro we are able to analyse diverse matrices including river water, sea water and wastewater, and with automatic dilution and high levels of sensitivity, we are able to measure a wide range of concentrations.”

Creating effective discharge consents
The analytical work undertaken by the laboratory at the University of Portsmouth has greatly improved the understanding of the ecology of the River Itchen and thereby informed the development of appropriate discharge consents for the two watercress farms. Effective 1^st January 2016, new discharge permits were issued by the Environment Agency that set limits on phosphate discharges to the River Itchen system. For the Vitacress Pinglestone Farm these limits are set at 0.064 mg/L and are measured as an annual mean increase compared to the inlet sample.

S&TC now works closely with Vitacress, monitoring immediately downstream of the discharge so that the effects of the new discharge limit can be effectively assessed.

Looking forward, Lauren says: “The lessons that we have learned on the Itchen are transferrable, and do not just apply to chalk streams. All rivers have their issues and inputs, so proper diagnosis and understanding of how these inputs shape the biology is essential to the successful restoration of degraded systems.

“In an ideal world phosphorus targets would be bespoke, on a river by river basis, and determined by tailored research and proper monitoring.

“River ecology is impacted by a wide variety of factors and whilst nutrients represent a serious risk, it is important for us to understand all of the threats, and the relationships between them. In summary, without high-resolution monitoring, river standards and river restoration efforts will be blind to their consequences.”

#SealAnalytical #Environmental @SalmonTroutCons @_Enviro_News

Nigel Grimsley from OTT Hydrometry describes relatively new technologies that have overcome traditional barriers to the continuous monitoring of phosphate and nitrate.

The science behind nutrient pollution in rivers is still poorly understood despite the fact that nitrate and phosphate concentrations in Britain’s rivers are mostly unacceptable, although an element of uncertainty exists about what an acceptable level actually is. Key to improving our understanding of the sources and impacts of nutrient pollution is high-resolution monitoring across a broad spectrum of river types.

Background

Green Box Hydro Cycle

Phosphates and nitrates occur naturally in the environment, and are essential nutrients that support the growth of aquatic organisms. However, water resources are under constant pressure from both point and diffuse sources of nutrients. Under certain conditions, such as warm, sunny weather and slow moving water, elevated nutrient concentrations can promote the growth of nuisance phytoplankton causing algal blooms (eurtrophication). These blooms can dramatically affect aquatic ecology in a number of ways. High densities of algal biomass within the water column, or, in extreme cases, blankets of algae on the water surface, prevent light from reaching submerged plants. Also, some algae, and the bacteria that feed on decaying algae, produce toxins. In combination, these two effects can lower dissolved oxygen levels and potentially kill fish and other organisms. In consequence, aquatic ecology is damaged and the water becomes unsuitable for human recreation and more expensive to treat for drinking purposes.

In its State of the Environment report, February 2018, the British Environment Agency said: “Unacceptable levels of phosphorus in over half of English rivers, usually due to sewage effluent and pollution from farm land, chokes wildlife as algal blooms use up their oxygen. Groundwater quality is currently deteriorating. This vital source of drinking water is often heavily polluted with nitrates, mainly from agriculture.”

Good ecological status
The EU Water Framework Directive (WFD) requires Britain to achieve ‘good status’ of all water bodies (including rivers, streams, lakes, estuaries, coastal waters and groundwater) by 2015. However, only 36% of water bodies were classified as ‘good’ or better in 2012. Nutrient water quality standards are set by the Department for Environment, Food & Rural Affairs (DEFRA), so for example, phosphorus water quality standards have been set, and vary according to the alkalinity and height above mean sea level of the river. Interestingly, the standards were initially set in 2009, but in 75% of rivers with clear ecological impacts of nutrient enrichment, the existing standards produced phosphorus classifications of good or even high status, so the phosphorus standards were lowered.

Highlighting the need for better understanding of the relationships between nutrients and ecological status, Dr Mike Bowes from the Centre for Ecology & Hydrology has published research, with others, in which the effects of varying soluble reactive phosphate (SRP) concentrations on periphyton growth rate (mixture of algae and microbes that typically cover submerged surfaces) where determined in 9 different rivers from around Britain. In all of these experiments, significantly increasing SRP concentrations in the river water for sustained periods (usually c. 9 days) did not increase periphyton growth rate or biomass. This indicates that in most rivers, phosphorus concentrations are in excess, and therefore the process of eutrophication (typified by excessive algal blooms and loss of macrophytes – aquatic plants) is not necessarily caused by intermittent increases in SRP.

Clearly, more research is necessary to more fully understand the effects of nutrient enrichment, and the causes of algal blooms.

Upstream challenge
Headwater streams represent more than 70% of the streams and rivers in Britain, however, because of their number, location and the lack of regulatory requirement for continuous monitoring, headwater streams are rarely monitored for nutrient status. Traditional monitoring of upland streams has relied on either manual sampling or the collection of samples from automatic samplers. Nevertheless, research has shown that upland streams are less impaired by nutrient pollution than lowland rivers, but because of their size and limited dilution capacity they are more susceptible to nutrient impairment.

Monitoring technology
Sampling for laboratory analysis can be a costly and time-consuming activity, particularly at upland streams in remote locations with difficult access. In addition, spot sampling reveals nutrient levels at a specific moment in time, and therefore risks missing concentration spikes. Continuous monitoring is therefore generally preferred, but in the past this has been difficult to achieve with the technology available because of its requirement for frequent re-calibration and mains power.

High resolution SRP monitoring has been made possible in almost any location with the launch by OTT Hydromet of the the ‘HydroCycle PO4’ which is a battery-powered wet chemistry analyser for the continuous analysis of SRP. Typically, the HydroCycle PO4 is deployed into the river for monitoring purposes, but recent work by the Environment Agency has deployed it in a flow-through chamber for measuring extracted water.

The HydroCycle PO4 methodology is based on US EPA standard methods, employing pre-mixed, colour coded cartridges for simple reagent replacement in the field. Weighing less than 8kg fully loaded with reagents, it is quick and easy to deploy, even in remote locations. The instrument has an internal data logger with 1 GB capacity, and in combination with telemetry, it provides operators with near real-time access to monitoring data for SRP.

The quality of the instrument’s data is underpinned by QA/QC processing in conjunction with an on-board NIST standard, delivering scientifically defensible results. Engineered to take measurements at high oxygen saturation, and with a large surface area filter for enhanced performance during sediment events, the instrument employs advanced fluidics, that are resistant to the bubbles that can plague wet chemistry sensors.

Environment Agency application
The National Laboratory Service Instrumentation team (NLSI) provides support to all high resolution water quality monitoring activities undertaken across the Agency, underpinning the EA’s statutory responsibilities such as the WFD, the Urban Waste Water Directive and Statutory Surface Water Monitoring Programmes. It also makes a significant contribution to partnership projects such as Demonstration Test Catchments and Catchments Sensitive Farming. Technical Lead Matt Loewenthal says: “We provide the Agency and commercial clients with monitoring systems and associated equipment to meet their precise needs. This includes, of course, nutrient monitoring, which is a major interest for everyone involved with water resources.”

Matt’s team has developed water quality monitoring systems that deliver high resolution remote monitoring with equipment that is quick and easy to deploy. There are two main options. The ‘green box’ is a fully instrumented cabinet that can be installed adjacent to a water resource, drawing water and passing it though a flow-through container with sensors for parameters such as Temperature Dissolved Oxygen, Ammonium, Turbidity, Conductivity pH and Chlorophyll a. Each system is fitted with telemetry so that real-time data is made instantly available to users on the cloud.

Conscious of the need to better understand the role of P in rivers, Matt’s team has integrated a HydroCycle PO4 into its monitoring systems as a development project.
Matt says: “It’s currently the only system that can be integrated with all of our remote monitoring systems. Because it’s portable, and runs on 12 volts, it has been relatively easy to integrate into our modular monitoring and telemetry systems.

“The HydroCycle PO4 measures SRP so if we need to monitor other forms of P, we will use an auto sampler or deploy a mains-powered monitor. However, monitoring SRP is important because this is the form of P that is most readily available to algae and plants.”

Explaining the advantages of high resolution P monitoring, Matt refers to a deployment on the River Dore. “The data shows background levels of 300 µg P/l, rising to 600 µg P/l following heavy rain, indicating high levels of P in run-off.”

Nitrate
Similar to phosphates, excessive nitrate levels can have a significant impact on water quality. In addition, nitrates are highly mobile and can contaminate groundwater, with serious consequences for wells and drinking water treatment. Nitrate concentrations are therefore of major interest to the EA, but traditional monitoring technology has proved inadequate for long-term monitoring because of a frequent recalibration requirement. To address this need, which exists globally, OTT Hydromet developed the SUNA V2, which is an optical nitrate sensor, providing high levels of accuracy and precision in both freshwater and seawater.

The NLSI has evaluated the SUNA V2 in well water and Matt says: “It performed well – we took grab samples for laboratory analysis and the SUNA data matched the lab data perfectly. We are therefore excited about the opportunity this presents to measure nitrate continuously, because this will inform our understanding of nitrate pollution and its sources, as well as the relationship between groundwater and surface water.”

Summary
The new capability for high-resolution monitoring of nutrients such as phosphorus will enable improved understanding of its effects on ecological status, and in turn will inform decisions on what acceptable P concentrations will be for individual rivers. This is vitally important because the cost of removing P from wastewater can be high, so the requirements and discharge limits that are placed on industrial and wastewater companies need to be science based and supported by reliable data. Similarly, nitrate pollution from fertilizer runoff, industrial activities and wastewater discharge, has been difficult to monitor effectively in the past because of the technology limitations. So, as improved monitoring equipment is developed, it will be possible to better understand the sources and effects, and thereby implement effective prevention and mitigation strategies.

@OTTHydrometry @EnvAgency @CEHScienceNews #Water #Environment

Extreme weather is becoming increasingly common throughout the world, making flooding a growing threat. Flood defence measures have traditionally been based on mechanical equipment, but innovative automation technology can now be used to provide greater protection for people and the local environment. AWA – the Office for Water and Waste in the Swiss canton of Berne – is using this latest technology to regulate water levels at the region’s Brienzersee, Thuner and Bielersee lakes, 24 hours a day, 365 days a year.

“Water level regulation must protect people from flooding and prevent damage – ideally in an economically justifiable way,” said Dr Bernhard Wehren, head of maritime regulation at AWA. “Some of our important control operations are particularly time-critical, but until recently, we relied on dataloggers that only sent the different measurements we require every few hours or so. Now, thanks to the new state-of-the-art technology we have implemented, this happens in real time. It is therefore very important that the data communications technology supports this by reliably meeting all the challenges and requirements of our unique mission-critical communications infrastructure.”

Modernising facilities
To help provide the most reliable flood protection, AWA decided to modernise its water regulation facilities for the lakes, encompassing four historic locks, the large Port of Bruggweir and accompanying hydropower plant, and a flood relief tunnel. Due to the increasing demand for the availability of more data, AWA also decided to upgrade all the measurement stations with state-of-the-art technology. The measurement stations play a crucial role in regulating water levels in the lakes.

When developing a plan to modernise the equipment, great attention was paid to both operational safety and system redundancy. There was a need to address the obsolete electrical engineering at Port of Brugg. This would include the conversion of all existing drives and the renewal of the energy supply, a large part of the cabling and the control and monitoring elements for the five weirs. Regulation and control technology also needed attention. Not only was there a need for redundancy in the event of a device failure or a line interruption, but also in case of communication disruptions, such as interruptions to the internet connection.

BKW Energie AG was appointed as the technical service provider and after a thorough review of suitable data communications technology companies, they chose Westermo to provide its robust networking solutions for the project.

Fast communication performance
“Crucial to the selection of Westermo was that their products met our high standards and requirements for the project. This included fast communication performance, multiple routing ports per device, high MTBF periods, extended temperature ranges and very low power consumption,” said Rénald Marmet, project engineer at BKW Energie. “Another factor was the operation and parameterisation of the networking hardware via the WeOS operating system. Also, the extremely efficient and time-saving update capability provided by the WeConfig network management software, which enables the central configuration and management of all Westermo devices.”

The main control network incorporates the AWA control centre in the capital, Berne,and further control centres at the water locks, Thun and Interlaken, each with one SCADA server and redundant controller. The control centres connect to 29 substations (measuring points). Eight SCADA clients access these servers. There is also a SCADA server located in the hydropower plant, providing BKW employees with access. The hydropower plant part is monitored by the BKW control centre in Mühleberg.

Westermo networking technology allows all data to be transferred in real-time between the participating sites. Should an emergency arise, this enables those responsible to take the appropriate measures immediately to ensure the best possible protection against flooding. Also, maintenance and software updates for all the installed Westermo networking devices can be performed easily and quickly with just a few mouse clicks.

In total, Westermo provided thirty of its RFIR-227 Industrial Routing Switches, twenty-seven VDSL Routers, twenty-fiveMRD-4554G Mobile Routers, thirty-five Lynx 210-F2G Managed Ethernet Switches with Routing Capability, thirty-six L110-F2G Industrial Layer -2 Ethernet Switches, and over eighty 100 Mbps and 1 Gbps SFP fibre optic transceivers via multimode and single-mode fibre for distances up to 80km.

Greater network redundancy
The three control centres all have two firewall routers connecting them to the internet providers and enabling them to receive or set up the IPsec and OpenVPN tunnels. There are also two redundant Siemens Simatic S7-400controllers installed in a demilitarized zone (DMZ) and a WinCC SCADA server connected to the local network. The AWA SCADA station has the same design, but without the control functionality.

BKW took care not only to create network redundancy, but also to set up redundant routes to the internet providers. The VDSL routers use the service provider Swisscom, and the MRD-455 4G mobile radio routers are equipped with SIM-cards from Sunrise. The heart of the main network – the three control centres and the AWA control centre- are linked by IPsec-VPN Tunnels and Generic Routing Encapsulation(GRE) and form the automation backbone via Open Shortest Path First(OSPF) technology.

The result of this is that even should there be simultaneous connection failure to an internet provider in one location and the other provider at another station, or the total failure of one provider, communication between all centres, the connected remote stations and the remote access by BKW or AWA is still possible.

For increased safety, the external zones are segmented further. The service technicians can connect to the control centres through an OpenVPN tunnel and have access to all measuring stations on the network.

There are two different types of measuring stations. The high availability station consists of two completely separate networks. Each PLC is installed ‘behind’ a Westermo Lynx 210 device, which acts as a firewall and establishes the connection to the control centre via an OpenVPN tunnel. The redundant internet access is provided either via a VDSL router, which is connected to Swisscom, or a MRD-455 with Sunrise as the provider. A ‘standard’ station has only one PLC with a Lynx 210 acting as a firewall router and building the VPN tunnels in parallel via the two internet routers.

Security requirements
As well as network redundancy, security was also part of the requirements to guarantee high communication availability. The network implemented by BKW and Westermo provides the necessary security in accordance with recommendations found in the BDEW whitepaper and IEC-62443 standard. The outstations not only form their own zone, but other areas are also segmented where necessary. The network for the SCADA servers in the control centres is also decoupled from the backbone using two VRRP routers.

The flood defence system now has one of the most modern data communication systems in Switzerland. Explaining why this is so important to AWA, Dr Bernhard Wehren said: “Protection against flooding must be guaranteed at all times. Depending on the meteorological or hydrological situation, the availability of the required measured values is critical. Because access to the measuring stations in the extensive regions of the canton is generally very time-consuming, network device failures and communication interruption must be kept to a minimum. It is therefore extremely important that all components of our communication systems meet the highest standards, offer extreme reliability and can be upgraded to meet new requirements.”

“We were able to simplify processes, make them secure, redundant and transparent for the engineering department via VPN connections. This contributes significantly to the simple, safe and efficient maintenance of the system,” Rénald Marmet said. “Thanks to the extensive cooperation with Westermo network engineers, we were able to create the ideal solution that meets all requirements and was delivered on time. Westermo’s reliable networking technologies have given AWA and BKW the opportunity to build individual data communication solutions for critical industrial applications, while providing scalable, future-proof applications. The solution also offers all involved a high degree of investment security.”

#Switzerland. @Westermo @bkw #Environment #PAuto

A number of British landfill operators are turning wastewater into a resource by utilising OTT monitoring and control systems to manage the irrigation of Willow crops (for renewable energy generation) with pre-treated effluent.

Background
Leachate from landfill sites represents a significant potential environmental liability, extending long into the future after a landfill site has closed. Conventional treatment and disposal options involve biological treatment and consented discharge to either the wastewater treatment network or to the environment. Alternatively, effluent may be collected by tanker for treatment and disposal off-site. However, to improve sustainability and broaden the treatment options, work initiated in the 1990s developed an approach that sought to use effluent as a source of nutrients and water for a Short Rotation Coppice (SRC) crop planted upon the restored landfill.

Willows fed on wastewater!

Following the success of early trials, the Environment Agency published a Regulatory Position Statement in 2008, which said: ‘SRC as part of a landfill leachate treatment process… is a technique (that) can be an environmentally acceptable option if managed appropriately.’

Early systems were operated and managed manually but with the addition of OTT sensors, telemetry and control systems, the process was automated to optimise irrigation and maximise both the disposal of effluent and biomass yield.

Willow SRC has become increasingly popular in environmental restoration work, providing a cost-effective material for stabilisation and reclamation of disturbed landscapes, bioremediation and biomass production.

SRC involves the planting of high yielding varieties of willow at a high density, typically 15,000 plants per hectare. The crop can be expected to last for around 30 years, with harvesting taking place every 3-5 years, and yields varying from 8 to 18 tonnes of dry woodchip per hectare per year. Willow grows quickly and has a particularly high demand for water, so it is ideal for the disposal of large volumes of treated effluent. In addition, the high planting density results in the development of a dense root hair system; effectively creating a biological filter for the treatment of organic compounds and the absorption of nutrients and some heavy metals. Soil fauna help to break down the effluents applied to the crop and soil particles control the availability of nutrients to the willow.

Monitoring and control
In early schemes, irrigation was managed manually on a timed basis with irrigation quantities based on external estimates of evapotranspiration. However, increased levels of monitoring and control are now possible. OTT’s Matthew Ellison explains: “The key objective is to supply the crop with an optimised amount of water, whilst minimising the requirement for staff on site. Too much irrigation would cause run-off and too little would under-utilise the treated effluent and result in poor growth conditions which would affect yield and potentially threaten the crop.

Soil moisture sensors

“An on-site weather station feeds local weather data to the system which uses crop data to predict evapotranspiration that is used to determine irrigation rates. Soil moisture sensors then check that soil moisture status is correct. Other sensors monitor the performance of the system; checking irrigation feed reservoir level, in-pipe pressure and there are sensors to check flow rates from the drip-feed irrigation. This communication capability is made possible with OTT’s Adcon Telemetry radio network.

“Our latest monitoring and control equipment automates the management of the system for unattended operation and staff are only required by exception. This means that the system is able to operate autonomously, delivering regular data reports, and staff are notified by email or text if alarm conditions occur.”

Emphasising the advantages of controlling the entire network, Matthew adds: “This system facilitates the ability to control and synchronise the main pump, and to open and close the valves at each irrigation zone.”

The latest OTT monitoring and control systems include:

1. Soil moisture sensors
2. Irrigation tank level sensors
3. Irrigation function check sensors
4. Pipe valves and pressure sensors
5. Automatic weather station (to calculate local evapotranspiration)
6. Radio telemetry
7. ADCON Gateway and PC running addVANTAGE software
8. Internet connectivity for remote log in

Summary
Looking back over a number of SRC projects, Stephen Farrow one of the instigators of this approach in the UK, and now an Independent Consultant says: “When viewed practically, environmentally and commercially, experience has demonstrated the viability of the overall approach.

“It is also clear that process optimisation with relatively low cost investment in OTT’s monitoring and control equipment has significantly added to the support functionality in terms of both operation and regulatory management.’’

OTT’s Matthew Ellison agrees, adding: “SRC clearly offers a sustainable option for effluent treatment, with highly positive effects on carbon footprint and biodiversity.

“In addition to the environmental benefits, process automation has significantly reduced labour requirements and helped to demonstrate compliance with the site-specific requirements of the Environment Agency.”

By Brian Booth, VP of the Water Treatment Innovation Platform, NCH Europe

There’s a lot of chemistry, physics and maths involved in perfecting your water treatment solution. To make sure you successfully treat and protect your system you need to get the equilibrium right, and this relies on balancing all the appropriate equations – even the little things you may not give much thought to. Missing something like half life out of your planning can have serious negative implications for your water treatment, especially when it comes to complying with regulations such as those for Legionella control.

When dosing your water cooling system with biocides it’s imperative that the concentration is correct and that it remains at a continuous concentration for a suitable period of time. While this sounds simple, it’s easy to forget that any bleed water required to compensate for water that may evaporate out of a system, will take a portion of your biocide with it.

Say you put 10 tonnes of make-up water into your system, and every hour 1 tonne runs off as bleed water, this will determine the half life for your system. So for example, let’s imagine the chemical you are using to meet the Government’s Health and Safety Executive (HSE) Legionella control L8 Code of Practice needs to remain at a concentration of 100 parts per million (ppm) for three hours to be successful.

If you just dose 100ppm and walk away, the concentration will gradually fall from the time of dosing and will not remain high enough for long enough as the bleed water will take a portion away with it. This will result in a failure to meet the regulation, making you negligent and leaving you liable.

This is why it’s vital to be aware of half life so that you can increase the dose of your biocide accordingly. Do you know how many hours it would take to reduce a 100ppm dose to 50ppm in your water cooling system?

Although it’s hard to be 100 per cent accurate, you can work out your half life with this simple equation:

If you know your biocide is going to take three hours to be effective, but the half life of your system is one hour you’re going to have to make some adjustments to maintain appropriate concentration. For instance, using our above example of legionella control biocide, to stay at a minimum of 100ppm for long enough you’ll need to dose to 800ppm.

A bit of predictive mathematics goes a long way towards protecting your water system and keeping you compliant. Don’t let a little thing like half life leave you vulnerable to negligence claims – do the maths first!