Pump Technology & Innovation

When Covid-19 restrictions were lifted and people started to take holidays in the UK, Wales had an influx of tourists which highlighted a shortfall in the amount of potable water available.

A plan was drawn up to upgrade strategic Water Pumping Stations operated by DwrCymru (Welsh Water) to increase the flow to its underground reservoirs and keep water flowing throughout the summer holiday. To keep water flowing while works were being carried out at Cornerpiece pumping station, Selwood’s solutions teams were asked to support with a temporary overpump setup which could be automatically put into action when needed.

The challenge

The customer was able to access a piece of the farmland just behind the original pumping station which would house site cabins and a set of generators to run the temporary pump setup. The size of the property presented challenges when it came to deciding where to place the equipment for the overpumping operation. The setup needed to be completely automatic that it would run at a pre-set pressure and flow with the flick of a switch.

The other challenge was the flow and head of the system to meet the required flows, Selwood’s teams were asked to produce 63 litres per second at 110m head, with an inlet pressure of between 3 – 4 bar.

The solution

One pump on its own wouldn’t produce the flow that was needed so two pumps would need to run at the same time.

Selwood’s solution was to use three 55kw Lowara WRAS approved pumps in a Duty 1, Duty 2 and standby configuration. The pumps were coupled with 6”clean water flanged pipework bolted together to make a manifold with a single suction and single discharge connection.

The pumps and pipework were all built up in the depot ready so once the pumps landed on site they only needed to bolt together four flanges. The pumps were controlled via 55kw variable speed drives (VSD) linked to an IFM inlet pressure sensor with programable set points which could be set to shut the pumps down under low suction pressure and prevent the pumps running dry. There was also a 4 to 20m pressure sensor fitted to the discharge pipework which could control the discharge pressure and speed the pumps up or slow them down to maintain outlet pressure when the VSD panels were set to PID (proportional integral derivative) loop. Multiple parts of the VSD program were changed to suit the application:

Ramp up and ramp down times were extended to help against surge pressure.

A start delay timer ensured the generator would have time to warm up.

The result

The result was the customer could run their own pumps while the upgrade works were going on – but if a problem such as a pump failure occurred, they could just flick a switch and the temporary over pumping solution would take over without any other human input. The system was designed to mimic the existing pumping station with the minimum of downtime.

The recommendation

Jason Sanders, SEMD Delivery Manager, DwrCymru, said: “From the initial enquiry right through to the commissioning, Selwood gave great advice and support throughout the entire process. The project started with a site visit to the existing pumping station to ensure all needs were discussed with both the current flows and the proposed flows. Selwood provided a pump selection to suit DCWW design requirements for the Cornerpiece WPS system. It was a smooth transaction from start to finish with the temporary pumps now available to ensure the increased flows to the storage reservoir.” www.selwood.co.uk

In wastewater measurement, accurate readings are essential to ensure proper pump operation. If such a measurement system fails, unhygienic wastewater can overflow and pollute the environment.

The pump systems themselves can also suffer damage if operated incorrectly on the basis of erroneous measurement values. Among other things, wastewater contains organic compounds such as proteins, carbohydrates and fats (grease). The latter in particular have the unpleasant habit of clumping together and forming sediments that are difficult to dislodge.

False measurements due to the formation of sediments

Newport News, Virginia in the USA offers a good example of what can happen in such a situation. Newport News was founded in 1621. It is situated along the James River and its nearly 180,000 residents make it the fifth largest city in Virginia. Here, several restaurants were built in an area serviced by the same municipal wastewater lift station. The high grease content in the wastewater then polluted the existing level measurement equipment, ultimately leading it to break down completely.

Antiquated solutions

Prior to the development of the commercial district, the Newport News Waterworks and the Hampton Roads Sanitation District relied on a combination of mechanical floats and conventional submersible transmitters. Both measurement systems stopped working after the restaurants opened: Both the primary and redundant level measurement equipment failed to properly transmit level data to the pump controller. The heightened grease content in the wastewater caused by the restaurants led clumps to form on the level transmitter membranes, which ultimately blocked the flow of water to the measuring membrane. On the redundant float switch, whose purpose was to trigger the pump in the event of a failed level transmitter, the accumulation of grease blocked the mechanical operation of the float ball. The failure of the level transmitter and the backup system led to the failure of the entire lift station because the pumps either operated constantly or not at all. If technicians hadn’t acted quickly, the entire sewage system could have come to a complete standstill.

Kynar® membrane offers better resistance

If a lift station is to function properly, grease must not be allowed to block the measuring devices. Various manufacturers offer nonfouling products that often present difficulties in other areas, however. The instruments usually employ a Teflon-coated elastomer membrane, which, while non-fouling, is also relatively weak and prone to puncture. The membrane is therefore equipped with a rather bulky protective shield that is mounted on bolts. Grease tends to accumulate in the gaps that result from this setup, however, which means the problem just moves to another location, as clumps of fibres, grease and sludge form the wastewater continue to impair correct measurements.

In the case of Newport News, city officials contacted KELLER Pressure, whose 36KyX level transmitter, which is known in the USA as the LevelRat, enables a unique approach to wastewater level measurement.

The Kynar® membrane used in the 36KyX is harder and offers superior abrasion and puncture resistance relative to other nonfouling solutions. Bulky shields are therefore no longer needed, which also enables a more compact design for the sensor. The 36KyX can fully exploit the advantages offered by a non-fouling membrane without anyone having to worry about floating particles and small objects. Put simply, the level transmitter is perfect for this application. No incorrect measurements due to grease deposits have been recorded at Newport News Waterworks since the new transmitters went into operation: The LevelRat solved the problem.

Wastewater treatment plant in Newport News

The 36KyX series was specially developed for brackish water and sewage applications. It is equipped with a non-fouling Kynar separating diaphragm, which combines the antiadhesion properties of PTFE with outstanding hardness and abrasion resistance. This level sensors design can be readily installed in harsh environments, eliminating the need for bulky, costly protective equipment. In addition to the RS485 interface, the measurement results can also be output via the integrated D/A converter as a rangeable analog signal.

keller-druck.com

Hydromarque has now completed a full re-branding exercise to ensure the company continues to be at the forefront of modern technology and to enhance its digital media presence in order to provide solid continuation to its customers, like Anglian Water for many years to come.

Hydromarque are the sole UK & Eire agent/ stockist/service provider for Gorman-Rupp Pumps, the market leaders in self-priming pump technology.

Based in the centre of the region, Hydromarque are ideally placed to support Anglian Water with their specialist range of self-priming, suction lift, solids handling pumps and associated spare parts and accessories. They hold a very large stock inventory of pumps and spare parts to enable them to deliver most items next day and minimise their customers production downtime. Not only do they provide a first class service, but they have over 100 years combined experience in applications, pump selection, commissioning, in-house repairs and troubleshooting. They also provide in-house and on-site training and have trained dozens of Anglian Water Engineers to ensure they are equipped with the know how to maintain the pumps on a day to day basis.

The Hydromarque team is experienced and dedicated to delivering excellent service and innovative pump solutions to existing customers like Anglian Water as well as new customers and enjoy the full back up and support of one of the most innovative pump manufacturers in the world.

range. The pumps are generally installed above ground and ‘high & dry’ above the liquid being pumped. This helps improve Health & Safety issues as it eliminates the need to enter below ground confined space areas and also assists with ease of maintenance as the pumps can be worked on locally, normally without the need for lifting equipment.

More recently, Gorman-Rupp has taken the concept of the solids-handling pump to a higher level of performance. For installations where stringy solids are affecting downtime and maintenance costs, there is now the Eradicator Solids Management System for the most common range, the Super T Series™ pump. The Eradicator is designed specifically for todays ‘new sewage’ issues such as sanitary wipes, plastic bags, hair, sludge and other types of debris.

Hydromarque have recently worked closely with Anglian Water on a project at Whitlingham STW. An emergency diesel driven pump has been supplied in the event that there be a power outage on site. It is process critical that the RAS [Return Activated Sludge] continues to be pumped. Working closely with the design team, Hydromarque selected a 10” pump from the Gorman-Rupp Super T Series™ S-Line range fitted with a Stage V diesel engine. These are capable of running on HVO [Hydrotreated Vegetable Oil] fuels, saving up to 89% on CO2 emissions.

In addition to this, Hydromarque are working closely with Anglian Water on their Storm Tank programme and their phosphorus removal ‘P’ schemes, where the surface mounted, selfpriming, solids handling pump is an excellent solution.

If you feel you need assistance with your pumping solutions then please don’t hesitate to contact the team at Hydromarque on 01733 370545 or sales@hydromarque.com

New sewage, poultry waste, plastic bags, hair, stringy material and other clog-prone materials can wreak havoc on pumps. That’s why you need a dependable solution for handling solid waste. Gorman-Rupp’s innovative Eradicator® Solids Management System upgrade kit for Super T Series® pumps offers just that. The new aggressive self-cleaning wearplate and back cover assembly, incorporating an obstructionfree flow path, are designed to handle clogprone material, keeping your pump operating at peak efficiency. A lightweight inspection cover allows for easy access to the inside of the pump without affecting wearplate-to-impeller clearance. And, the Eradicator can be easily installed into existing Super T Series pumps in the field.

Phone: 01733 370545 Fax: 01733 361249 Email: sales@hydromarque.com YouTube: Gorman-Rupp Eradicator® www.hydromarque.com