Society goes to the polls.

07/09/2016

Irish candidate goes forward for most senior role in Automation Society

The polls were opened recently for the election of leadership positions for 2017 in the International Society of Automation (ISA). The ballot is for election of new leaders by direct vote of eligible ISA members.

This year for the first time a candidate from the Ireland Section has been nominated for the position of President-elect Secretary. This position is a commitment for three years, the first year as Secretary of the Society, the second year as World-wide President and the third as Past President.

Those nominated for this (and indeed all officer positions in the Societed) are subjected to a rigorous pre-nomination process before their name is placed on the ballot paper. Nomination for an elected Society leadership position is an honour accorded to only a small percentage of the ISA membership.

Brian_J_CurtisBrian J. Curtis (G E Healthcare) Cobh, County Cork, Ireland (right), is one of the candidates this year. He has an impressive leadership background both in the automation industry and in other sectors industrial, commercial and recreational. He has 35 years Pharmaceutical Control Systems experience.

Speaking recently he told us that he has been a member of the ISA for over twenty years and has served in most offices in the very active local section. “I joined my local section to access ISA technical meetings, technical papers, standards and networking opportunities.” However he was also willing to participate more actively in the running of the Section and later in the greater Society, in Europe and Globally.

Brian served in many portfolios within the Ireland Section down through the years including a term as section president (1999-2000). He became Vice President District 12 of the Society (Europe, Africa & Middle East) in 2013.  He also served on the ISA Executive Board 2013 to date, and also on the important ISA Finance Committee. The various society offices involved visiting sections in Europe and the Middle East as well as attendance at various Society governance and  leadership meetings.  His service through the years has been recognised by the Society, as a recipient of the Distinguished Society Services Award, as well as recognition at Section and District levels. He says “My current challenge is working with ISA on our five strategic goals!”

electVoting in the Leadership Elections is relatively easy. Go to the ISA Home Page and look for the button “Vote Now” and follow the instructions.
Only eligible members may vote. You’ll need your ISA ID information of course.
The Ballot lists the candidates with a link to their Biographical details. The voting is simply a matter of ticking the candidate of your choice.

He shared his vision for the Society: “That ISA Sections and Divisions all work together so that membership and industry feel the benefits, both locally and globally, ensuring “ONE ISA” will prosper into the future.”

“I believe we must nurture the volunteer in the society and encourage sections, divisions and standards to work together across geographic and technical boundaries so as to harness and build upon the strength and integrity of ISA in meeting the automation challenges of the future.”

He is particularly in supporting the ISA’s pioneering work in the emerging area of cybersecurity. Industry and production methods are evolving at a fast pace and it is important to identify emerging trends and seize these as opportunities for our member’s and for automation.

He wants to strengthen the Society by encouraging co-operation and communications between sections, divisions, standards and all areas of ISA around the world. He is not afraid to support the tough strategic decisions that will allow ISA to continue to be the leader in the automation industry. It is important also to promote the lifelong opportunities that automation presents as a career for school and college graduates.

There are two other candidates for this position. They are Eric C. Cosman (OIT Concepts, LLC) Midland, Michigan, USA. He was one of the speakers at the groundbreaking Food and Pharmaceutical Symposium in Cork earlier this year. The other candidate is Glynn M. Mitchell (US Nitrogen) Greeneville, Tennessee, USA.

Although most of the Presidents of ISA since its foundation have hailed from the US there have been a handful of Presidents from other regions of the World.

#ISAuto #PAuto
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Reduce data centre asset liabilities.

07/08/2016
How you implement RFID monitoring is critical to the performance of the system.

Harting_Data_Centre_AppWith regular headlines about the latest cybercrime attack stealing important or commercially sensitive data, the physical security of IT equipment is often overlooked. One area in particular is the almost casual theft of small pieces of equipment from the racks. For example, the latest helium filled 10TB hard drive represent a €700  (£600stg) investment and with up to 22 drives used in a 4U storage array, loss through theft can be substantial.

The constant monitoring of what equipment is located inside the data centre has additional benefits not only in terms of security but also in managing cooling air-flow requirements and power consumption, which support growing need to demonstrate compliance with Green IT initiatives.

In response, data centres have been increasingly looking for cost efficient solutions for key asset management. Data Centre Infrastructure Management (DCIM)* is an emerging holistic management approach that combines traditional data centre equipment and facilities with monitoring software for centralized control. DCIM includes physical and asset level components and by combining both information technology and facilities management it raises the effectiveness of a data centre.

RFID has been seen by many as a key element to providing real-time monitoring of component location within the data centre. By installing passive RFID tags on every removable component of the rack data centre systems integrators and site operations managers can easily use them not only to record locations but more information about the device than they could before with standard asset tags.

But how you implement RFID monitoring is critical to the performance of the system.

Portable hand-held RFID reader systems have a very small UHF read range and only offer a slightly better performance than relying on paper records or barcodes because it requires employees to walk down aisles and identify the piece of equipment and its location. This is a very time-consuming task and as such is not undertaken very often. It also relies on the competence and integrity of the operator carrying out the check.

Fig1_HartingRFID

Fig 1

Up until now it has been unrealistic from a physical location point of view to directly integrate even the most compact passive RFID UHF patch antennas into existing data centre server rack arrays.

Typically, 4 antennas would have to be separately mounted either side of the front of each server rack, in both the upper and lower areas and carefully positioned to ensure there are no gaps in the RF field coverage. Correspondingly, with such an arrangement it would also be necessary to utilise multiple readers, resulting in excessive installed cost

Harting now have the ideal solution to remove this higher cost multiple patch antenna and reader arrangement with its innovative Ha-VIS RFID LOCFIELD® coaxial cable waveguide antenna.

They can be directly integrated, with insulating spacers, onto the rear side of the front access door of each server rack. Only one of these Ha-VIS RFID LOCFIELD® antennas needs to be fitted for a fully installed 45U sever rack. By fitting in an extended S-shape design (See Fig. 1) you can achieve the best possible RF field coverage of the complete rack. In conjunction with a single reader which has the required power to match the correct read distances, it can register passive RFID tags that provide specific item identification within a rack and additional sensor functionalities e.g. detecting empty or occupied slots, thus minimizing the complete data centre system installation cost.

The Ha-VIS RFID LOCFIELD® is a traveling wave RFID antenna consisting of a coax cable that—when plugged into the antenna port of a Harting UHF EPC Class1 Gen 2 reader—conveys the reader’s RF signal along the cable’s copper core and to the antenna’s far end, where a coupling element draws the RF wave out and onto the cable’s exterior. When that signal reaches the reader, a metal protecting shield prevents the interrogator from receiving its own signal and interfering with its performance. N.B. The Ha-VIS LOCFIELD ® antenna should not be mounted directly onto a metal surface but raised-off slightly with insulating spacers.

Fig2_HartingRFID

Fig 2 – Harting HA-VIS RFID LOCFIELD® antenna

By its functional nature the Ha-VIS RFID LOCFIELD® antenna facilitates real-time monitoring of movements in and out to the rack enclosure and is available in different lengths up to 10 metres and is 5 millimeters in diameter. If used with a high-powered reader, such as Harting’s Ha-VIS RF-R500 long range reader transmitting a signal of 4 watts (36dBm), it can read passive EPC Class 1 slot Gen 2 transponders located up to 2.5 metres away radially over its entire length.

Put simply Harting’s Ha-VIS RFID LOCFIELD® antennas allow you to identify what is in a data centre rack, its population status and where a specific item is located.

* DCIM was originally defined in the US and describes a methodology of IT and facilities management.
@Harting #PAuto

Manufacturing improvements with PLM.

04/05/2016
Adam Bannaghan, technical director of Design Rule, discusses three ways that the digital continuity of PLM helps manufacturers deliver high quality innovative products with ease.
Adam_Bannaghan

Adam Bannaghan

No one hates being faced with a problem they weren’t expecting more than manufacturers. During the design and build process, unplanned events can increase cycle times and have a detrimental impact on the management of materials and working hours. There is now a demand in the manufacturing sector for a system that provides real-time visual status and control, alongside product quality predictions. Enter, product lifecycle management (PLM).

 

PLM is used by different sectors for various reasons. For manufacturers, the virtual production element is used to improve the planning, management and optimisation of industrial operations. The software also allows users in multiple locations to work on projects simultaneously, tracking progress and inputting operational data. Manufacturers may not have as much paperwork to track or intellectual property to protect as other sectors, but there are three important reasons why manufacturers should invest in PLM software.

Immediate insight
When used as part of a PLM system, virtual production software can visualise the build of a product before the assembly line is in place. This means engineering and manufacturing directors can identify possible constraints and fix errors before the product reaches the manufacturing stage. Engineers can then evaluate ‘what-if’ scenarios months before making the commitment to production. Having a 3D visualisation of how the product interacts in the real world means designers can make changes, optimise operations and facilitate higher quality innovation.

For instance, misjudged timings are a major cause of product delay and error. Having this software in place ensures all parties developing or manufacturing a product are in sync. This synchronisation is referred to as digital continuity, where all parties have access to the same design at every stage of the design and build process. This optimises the manufacturing process, bringing lead times forward and helps those involved spot errors before they have a serious impact.

Smoother collaboration
Interconnectivity and the industrial internet have increased the complexity of PLM requirements, especially in operations planning, management and optimisation.

Many manufacturers now run their design and build operations across multiple locations. Distance, cultural differences and diverse approaches to problem-solving can sometimes result in costly production errors if seamless communication is not possible. By using software that bridges the gap between different locations, businesses can plan, manage and optimise industrial processes.

For example, a common problem when part measurements and specifications being are sent overseas for production is that poor translations or measurement system differences can sometimes cause costly production errors. Engineering teams can easily fix these errors in the manufacturing process, but they still cause delay, confusion and ultimately cost money. By using 3D virtual production software, users can communicate instructions and measurements clearly as well as alter specifications during the design stage.

Optimised manufacturing
The more complex a product is, the more critical the assembly process becomes. Software that allows companies to properly plan, simulate and implement production lines can benefit all departments, from design to engineering, sales and marketing. By implementing a digital continuity platform, all parties can start planning well in advance, bringing lead times forward and reducing the risk of missing deadlines.

Whether a company is experiencing geographical expansion, requests for more complex products or has a history of misjudged timings, implementing virtual production software, such as Dassault Systèmes’ DELMIA, could prevent you from getting a nasty surprise during your next project.

@DesignRulePLM #PAuto

Changing industry standards for OEMs Enginers & contractors: one year on!

04/10/2015

In 1998, Google was founded, the first Apple iMac was introduced and the legendary Windows ’98 was released by Microsoft. In a less glamorous but equally important corner of industry, a new commission was being formed to revise the complex IEC 60439 industry standard, which governed the safety and performance of electrical switchgear assemblies. Although Windows ‘98 has long been consigned to history, the new industry standard – BS EN 61439 – only became mandatory on November 1, 2014.

One year on, Pat McLaughlin, Boulting Technology’s Operations Director, evaluates how original equipment manufacturers, panel builders, electrical engineers, consulting engineers and contractors have been affected by the new BS EN 61439 standard.

Boulting_BS_EN_61439

Why a new standard?
In a market where the demand to optimise and reduce costs blends heavily with higher needs for assembly flexibility, the introduction of a new set of standards was needed to guarantee the performance of Low Voltage Switchgear Assemblies.

Switchgear and Control Gear assemblies are multifaceted and have an endless number of component combinations. Before the introduction of the new standard, testing every conceivable variant was not only time consuming and costly, but impractical.

The intricate character of assemblies also meant that many did not fit into the previous two testing categories: Type Tested Assembly (TTA) and Partially Tested Assembly (PTTA). For example, panels which were too small to be covered by TTA and PTTA fell outside the standard. Finally, in the case of a PTTA, ensuring the safety and suitability of a design was often dependent strictly on the expertise and integrity of the manufacturer.

Design verification
The major change introduced by the new BS EN 61439 standard refers to testing. It states that the capabilities of each assembly will be verified in two stages: design verification and routine verification. This means the new standard completely discards the type-tested (TTA) and partially type-tested assemblies (PTTA) categories in favour of design verification.

Although BS EN 61439 still regards type testing as the preferred option for verifying designs, it also introduces a series of alternative routes to design verification.

The options include using an already verified design for reference, calculation and interpolation. The BS EN 61439 standard specifies that specific margins must be added to the design, when using anything other than type testing.

One of the main benefits of the new design verification procedure is its flexibility. Under the old BS EN 60439 specification customers would demand a Type Test certificate for each assembly particularly Incoming Air Circuit Breakers, which was very expensive and time consuming.

The new standard allows users and specifiers to pertinently define the requirements of each application. Annex D of the BS EN 61439 standard provides a list of 13 categories or verifications required, what testing method can be used and what comparisons can be made. In order to optimise testing time, the standard allows derivation of the rating of similar variants without testing, assuming the ratings of critical variants have been established by test.

Dividing responsibility
The second major change implemented by the new industry standard refers to the responsibilities of each party involved in the design, test and implementation of low voltage switchboard assemblies. Unlike BS EN 60439, which stated the OEM or the system manufacturer was solely responsible throughout the testing programme, the new standard divides the responsibilities between the OEM and the assembly manufacturer, or panel builder.

The new standard recognises that several parties may be involved between concept and delivery of a switchboard assembly. The OEM is responsible for the basic design verification. In addition, the assembly manufacturer is meant to oversee the completion of the assembly and routine testing.

For innovators like Boulting Technology, the new BS EN 61439 has brought more freedom and flexibility when designing switchboard assemblies. For example, Boulting Technology has designed and launched the Boulting Power Centre, a range of low voltage switchboards, which are available in 25kA, 50kA, 80kA and 100kA, fault ratings, and up to 6300Amp current ratings.

Although change is never much fun, it’s what technology and industry are all about. If this wasn’t the case, we would all still be using Windows 98 or the indestructible Nokia 5110.


ABB Process instrumentation, analytical technology and gas detection in Ireland

19/01/2015

Hanley Measurement & Control has built a reputation for the supply of specialist solutions and expertise in process instrumentation, process analytical technology and gas detection. Founded in 1981 it has long been considered as a leading automation in Ireland. The company has recently been appointed as channel partner in Ireland by ABB, to expand its instrument and analyser offering into the Irish process market

Left to Right: Chris Kennedy, Gavin O’Driscoll & Eoin O’Neill of Hanley Measurement & Control together with Aidan Edwards of ABB stand next to a representation of a 3 meter magnetic flowmeter (the largest every supplied!) during a recent visit to the ABB flow meter manufacturing facility in Stonehouse, GB.

Left to Right: Chris Kennedy, Gavin O’Driscoll & Eoin O’Neill of Hanley Measurement & Control together with Aidan Edwards of ABB stand next to a representation of a 2.4 meter magnetic flowmeter (the largest every supplied!) during a recent visit to the ABB flow meter manufacturing facility in Stonehouse, GB.

The partnership will see the company acting as the official sales agent for ABB’s complete portfolio of instrumentation and analyser products for applications in the pharmaceutical, chemical, food and beverage and other related industries.

Chris Kennedy, Managing Director of Hanley Measurement & Control commented that “partnering with ABB enables the company to provide its customers with an enhance product range specifically in relation to flow measurement and analytical solutions.”

Commenting on the partnership, Tim Door, General Manager for ABB’s Measurement and Analytics business in the Britain and Ireland says: “The partnership with Hanley Measurement and Control marks a positive move forward that underlines our intent to grow our presence in the Irish process market. The company is a great fit for our growing range of measurement and control products for improving process performance and efficiency.”

“Utilising a well-known and respected partner such as Hanley Measurement & Control will allow our customers in Ireland to get full access to support and service going forward into 2015 and beyond.”

• Following the completion of a management buyout Hanley Measurement & Control is no longer part of the Hanley group of companies. Hanley Measurement & Control is now a subsidiary of Eolas Scientific which also has an operating company in the UK called Eolas Technology. The management team of Chris Kennedy, Gavin O’Driscoll and Eoin O’Neill are committed to ensuring our customers receive exceptional service and a world class range of products.

Failure is not an option!

18/10/2014

ProSoft Technology’s PROFIBUS Modules and Industrial Radios allow critical data to be transmitted from ControlLogix PACs at Flood Defense System.

Failure is not an option when upgrading a flood barrier’s control system. Should a flood barrier malfunction, thousands of homes and businesses could be severely impacted.

Upgrading a flood barrier isn’t a task that can be done overnight. It takes months and months of work. The barrier has to remain available for use throughout the upgrade, making it a considered and careful task. There has to be several fail safe measures and redundancies in place. Whoever said redundancies are a bad thing hasn’t taken a look at a flood barrier system.

dartford_scheme

Two concrete towers stand 20 meters above the ground on either side of the mouth of Dartford Creek. This is the UK Environment Agency’s Dartford Barrier Flood Defense System in Kent, South East England. The barrier is routinely closed, in conjunction with the bigger Thames Barrier upstream, to prevent high tide water levels in the River Thames Estuary flowing back up the creek and flooding Dartford and the surrounding area.

Two steel gates, each 30-metre across and weighing over 160 tons each, are suspended at high level between the two concrete towers. Like a huge guillotine at the creek mouth, one gate may be slowly lowered on its supporting chains onto the river bed to block the flow of water. Then the second gate may be slowly lowered to rest onto the top of the first gate. When closed together, the 160 ton steel gates can withstand up to 10.4 meters of water.

The gates are raised and lowered by direct drive oil hydraulic motors. The drive system comprises two 18.5kW pump and motor units, providing both duty and standby facilities, enabling a gate to be raised or lowered in 15-minutes. When not in use both gate structures are safely held in the fully raised position and latched using hydraulic latch mechanisms. This permits vessels to pass underneath the gates along the creek.

It is envisaged that due to climate change that the barrier may need to operate an average of 50 times per annum over the next 25 years.

“The system has to be highly available with many fallback systems in case of failures,” said Andrew Garwood, a Senior Contracts Manager in the Controls Division of Qualter Hall & Co Limited, Barnsley (GB).

Just a couple of years ago, the control system was starting to show its age. As part of a large upgrade to the barrier, its associated control system was overhauled. The original control system was a completely hardwired based relay system that was over 30 years old. Spare parts for the 30 year-old system were becoming scarce.

Qualter Hall provided the M&E contracted works on behalf of the principal contractor Birse Civils, who had engaged Qualter Hall as the Systems Integrator for the project and as the Mechanical and Electrical Engineering Contractor in charge of upgrading the control system; they had several goals in mind. Number one was safety and reliability. Flooding, should it occur, could cause extensive damage to the surrounding area.

instrument_inst_DartfordQualter Hall, who provides an attractive ‘one stop shop’ for a multitude of engineering solutions, decided to call ProSoft Technology. Qualter Hall selected this company, because it was a reliable, cost effective solution that was endorsed by Rockwell Automation. ProSoft Technology is a Rockwell Automation Encompass Partner.

Two Rockwell Automation ControlLogix redundant PACs are inside each of the 20-meter towers to control the opening and closing of the barrier, but much of the equipment the control system spoke to was PROFIBUS or Siemens based. Two PROFIBUS Master communication module (MVI56-PDPMV1) from ProSoft Technology were installed inside the ControlLogix PACs to facilitate communication from the Rockwell Automation processors.

“The ProSoft Technology modules were utilized to provide PROFIBUS DP into the ControlLogix rack and permitted four separate PROFIBUS DP segments for redundant operation,” Andrew Garwood said.
Fiber optic cables were installed between the two towers, as part of the control system overhaul. While the cable links were being constructed, ProSoft Technology 802.11 Industrial Hotspot radios served as the communication link.

“The wireless link was then used as an automatic fallback connection should fiber optic connection be lost. The ProSoft Technology equipment was selected for its flexibility and support of the spanning tree protocol (RSTP) “, Andrew Garwood said.

ProSoft Technology’s solutions helped ease the engineering work by making it possible for the ControlLogix system to communicate as one single protocol.

The system now allows data to be reviewed quickly, centrally and remotely, providing convenience when accessing diagnostic information.

Thousands of homes and businesses are now safely protected.


Process optimisation by Real-Time Control!

23/08/2014
Major installation at English sewage treatment works.

Wessex Water, an English water authority,  is investing around £20m at its Taunton sewage treatment works to improve the facilities for wastewater and sludge treatment in a project that is due for completion by the end of March 2015. The upgrade to the works under the DWF (Dry Weather Flow) Improvements Scheme will increase the site’s treatment capacity whilst also improving the efficiency and quality of the treatment process, lowering energy costs and reducing the site’s carbon footprint.

Prior to the implementation of the DWF Scheme, the STW was comprised of an inlet pumping station and balance tank, coarse and fine screens, grit removal (detritor), primary settlement tanks, a conventional ASP & biological filter beds, final & humus tanks and final effluent lagoons. The construction work involves the creation of a new four-lane ASP to replace the existing 16 biological filters. To facilitate this, one of the lagoons and four of the filters are being taken out of service to create space for the new works, and this has allowed all development to remain within the existing site boundaries enabling most works to be constructed under permitted development rights.

tauntonProcess optimisation of the new ASP stage will be achieved through implementation of Hach Lange’s Real-Time Control (RTC) system, which monitors influent ammonium concentration and dissolved oxygen concentrations along the aeration lanes, providing more efficient control of the fine bubble diffused aeration. The measurement of other quality parameters in the process train provides feedback to the RTC. A reduction of up to 15% energy usage is anticipated as a result.

Balfour Beatty has provided the civil works and Nomenca Ltd is responsible for the supply, installation, commissioning, and performance testing of the mechanical and electrical components of the new works. Contracts Manager Trevor Farrow says, “Nomenca’s reputation is built on a track record of successfully delivered projects, and the relationships that we develop with both clients and suppliers are key to this success. We have already worked with Hach Lange’s instrumentation on a wide variety of projects, so we are confident that this project will be a further success.”

As Project Manager for Wessex Water, Garry Orford says: “The drivers for this works upgrade include an increased treatment capacity requirement and a tightening of the consent, taking in to account longer-term requirements that may be implemented in AMP6. We have already implemented Hach Lange’s RTC process optimisation systems at our Holdenhurst plant – 175,000 PE – near Bournemouth, and this has delivered energy savings of around 25% so we are confident that we can repeat this success at Taunton – 85,000 PE.”

taunton2Following completion of the new works, the site will meet the following consent conditions:

  • Dry Weather Flow (DWF)   30,595 m3/d
  • Sanitary parameters BOD:SS:AmmN 15:30:3 mg/l

In addition to the upgrade of the sewage treatment facilities, a third anaerobic digester (AD) is also being built at the Taunton works. “This will increase our capacity to generate renewable energy and further reduce our electricity bill,” according to Garry Orford. “The power generation of the AD plants is fairly stable, but the energy demand of the treatment plant varies according to the load, so there will be occasions where we can sell energy back to the grid, and others where we will continue to have a power requirement. It is essential therefore that we use this power as efficiently as possible.” 

Real-Time Control in industrial processes is commonplace. However, wastewater monitoring represents a greater challenge because of its physical and chemical variability. Historically, wastewater monitoring technology was prone to drift (especially galvanic dissolved oxygen monitors) and required a high level of maintenance, so RTC was not feasible. However, the latest sensors offer much higher levels of reliability than was possible in the past, with substantially lower levels of maintenance and recalibration. This has been a major factor in enabling the development of RTC in wastewater treatment. In addition, many of the latest sensors provide a ‘health status’ output in addition to the readings. As a result, if any problems arise they can be quickly remedied, and control systems can ignore data from sensors that are not performing to their target specification.

Monitoring technology
The capital outlay for the addition of RTC to a treatment plant is relatively small; the most significant extra cost is the requirement for extra sensors plus the RTC unit. The Taunton build includes the installation of the latest sensors for dissolved oxygen, ammonium and turbidity, controlled by an sc1000 network, providing reliable data on the influent, and from within the treatment process.

IMG_0056The LDO sc dissolved oxygen sensor employs an optical luminescence method for calibration-free and drift-free measurements. Once the construction work is complete there will be four new lanes, each with three zones, so a total of 12 LDO probes will monitor dissolved oxygen.

In addition, two SOLITAX ts line dip probes will measure Mixed Liquor Suspended Solids (MLSS) content in the aeration lanes and the solids content of the Returned Activated Sludge. The RTC at Taunton will also control sludge retention time, which enhances plant efficiency. The suspended solids probes employ a patented dual scattered light method with a built-in wiper, to provide colour-independent measurement of solids without a requirement for calibration. Ammonium measurements will be undertaken at both the entrance and exit of the aeration lanes with two AMTAX sc instruments; high-precision analysers that continuously collect samples via an air-bubble cleaned filter probe. The ammonium analysers will be mounted directly over the filters to minimise the distance travelled by samples.

Real-Time Control
The Hach Lange RTC is implemented on an industrial PC which communicates with an sc controller network and the local PLC. The RTC system determines the most efficient aeration level and continuously feeds DO set points to the PLC which controls the blowers. This means that under RTC, DO set points are no longer ‘fixed’, instead they ‘float’ according to the load. The RTC modules continuously deliver set points to the PLC, which applies them to the process. This ensures that response to changing conditions is immediate. The algorithms employed by the N-RTC (Nitrification Real Time Controller) are mainly based on the Activated Sludge Models of the International Water Association.

The N-RTC also constantly reads the NH4-N concentration at the outlet of the aeration lane. This value provides a feedback control loop and ensures that the DO concentration is fine tuned to achieve the desired ammonium set point at the end of the ASP. In this way, the N-RTC control module combines the advantages of feed forward and feedback control, which are (1) rapid response, (2) set point accuracy and (3) robust compliance.

Aeration to achieve the biological oxidation of ammoniacal compounds to nitrate is the most energy intensive process at activated sludge plants because blower power consumption can represent over 50% of total costs at some plants. However, in addition to the advantages of the process optimisation system, four new Sulzer high speed HST-20 turbo-compressors are being installed by Nomenca, following trials on similar units by Wessex Water. These machines employ a control system that manages both the number of blowers to run, and the speed of the blowers, which will further improve energy efficiency.

Summarising, Garry Orford says: “Wessex Water has an ambitious long-term objective of carbon neutrality, and these improvement works projects provide us with useful opportunities to make a significant contribution to that goal.”