Water & Wastewater Treatment

Round table paRticipants Andrew Ball, Water Utilities Director, Grundfos John Bower, Consultant, British Pump Manufacturers Association (BPMA) Steve Burge, M&E Engineer, Wessex Water Tom Burgoyne, Energy Efficiency Monitoring Specialist, Anglian Water Matthew Griffey, Research Engineer, The University of Exeter/South West Water Darren Hewerdine, Asset Specialist, Energy & Pumping, Affinity Water Izabela Kasak, Energy Optimisation Engineer, Anglian Water Tom Mills, Senior Maintenance Lead, Veolia Water Alastair Tawn, Wastewater Energy & Efficiency Manager, Northumbrian Water Bob Turner, Range Manager, Pumps, United Utilities Richard Willetts, Energy Performance Manager, Southern Water 10 | JULY 2017 | WWT | www.wwtonline.co.uk The Talk Round Table: Pumps and energy W ith water companies being some of the country's biggest energy users, and pumps making up a hey proportion of the energy that they use, it is only natural that pumps are a focus for efficiency and sustainability efforts in the water industry. Utilities could save millions on their energy bills, and reduce carbon emissions to boot, if they could ensure that their pumping assets are using only the minimum amount of energy necessary for the job at hand. However, there are a number of strands to this challenge – making sure that new pumps are correctly sized and chosen with efficiency in mind; that existing pumps are controlled in a way that they run at full speed only when needed; that pumps are maintained properly to stay efficient; and that pumps that are losing efficiency at the end of their life are identified and replaced at the right time. These challenges and more were discussed at length in the WWT roundtable 'Optimising the energy use Monitoring and maintenance the key for pump optimisation these were installed in the days of local authorities, when there was a lot more money", according to one participant. The cost of installing pump scheduling is too high for water companies to be able to make use of it at every treatment works, it was noted. The participants agreed that Totex (total expenditure) was a primary consideration in purchasing pumps, but there were some inconsistencies in the way this is being applied, with pumps installed on capital projects more likely to be subject to a thorough consideration of whole-life energy costs than those bought to replace existing assets at short notice. When it comes to pump monitoring, digitalisation has great potential in providing operation information that can then be used to lower running costs and extend pump life. Anglian Water has made great strides in this department through its Energy Efficiency Monitoring System (EEMS) which is being rolled out to cover a significant proportion of the utility's pumps. Participants agreed that continuous monitoring using digital technology was a valuable tool which would yield an abundance of information to drive energy costs down. Going one step further, extending digital technology into pump control could make controlling the rate of pump use "an exact science", and be a gamechanger for water companies, it was predicted. Some attendees are currently undergoing trials of such technology. United Utilities, for example, is trialling a number of digital control systems which it is using to measure pump dynamic efficiency, energy use, flow rates to predict pump life. And, for sites where it has multiple pumps pumping to the same reservoir via the same network, the system will determine which is the most efficient combination of pumps. However, the struggle is getting operations teams to utilise digital control systems to their full potential, observed one participant. Operations teams come up with "endless reasons" for doing things in a traditional way rather than trusting the technology. Moreover, digital controllers are currently expensive – around £10,000 per pump, according to this speaker – "which takes a lot of justifying." The conversation turned to the value of sub-metering, which allows companies to obtain more in- depth data and is required by some energy standards such as ISO50001. Implementing such systems does have of pumps' held in London on May 17th in association with Grundfos. One of the problems with sizing pumps correctly is the unpredictability of the British weather, said participants. Water utilities must ensure that pumping stations are designed to cope with the severe flooding that might follow a 1-in-a-100- year storm, but dry weather presents its own problems. Attendees pointed out that unexpectedly dry weather at the beginning of May this year meant that huge pumps had to be running right at the bottom of their capabilities, just to deal with the low flows that were being experienced. This way of operating is not only inefficient, but can cause issues such as cavitation and overheating if motors aren't given time to cool down properly. Pump scheduling - where different- sized pumps kick in to do different duties – is one way to combat this issue. Some water companies have plants with pump scheduling built in, which work well. However, "most of

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