WATER & WASTEWATER MANAGEMENT
SMART SLUDGE SOLUTION Thames Water rolls out a novel energy-reducing sludge solution
distance transfer with reduced operational costs by using a combination of PC pump technology and dense-phase conveying. T e technology has already been trialled by T ames Water at its Reading Sewage Treatment Works (STW) and is now being installed as part of the new T ames Water Riverside project, providing an energy- effi cient, high-performance alternative to conventional sludge handling systems. Seepex has a longstanding relationship
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with T ames Water, having worked for many years to increase the water company’s process effi ciency and reduce the energy consumption of dewatered biosolids sludge handling. As the UK’s largest water and sewage treatment company, T ames Water provides wastewater services to 15 million customers and is committed to reducing its energy consumption. Its interest in smart air injection (SAI) technology was linked to a new project at Riverside STW to handle dewatered sludge. Following a visit by T ames Water
representatives to observe SAI in action in Sweden, the company decided to measure the potential energy savings it could make by installing a trial SAI system at its Reading STW. T is site had previously used piston pumps, but as a result of process limitations and high operating costs, T ames Water switched to Seepex’s multistage PC pumps in 2014. T is solution halved energy use, as well as reducing transport and maintenance costs. Four years on, it was time to see if SAI could improve things further.
ne of the leading progressive cavity pump specialists has developed a new system to improve dewatered sludge handling, enabling long
The Seepex solution has allowed Thames Water to reduce pump length and installed motor power, and has improved maintenance
T e SAI Reading trial set out to not only
prove the technology, but also to quantify the additional energy savings that could be delivered by pumping the dewatered biosolids from the centrifuge discharge to the storage silo. An SAI trial unit, including full controls and monitoring, was installed on the multistage PC pumps for a trial period and the results were recorded.
Seepex’s smart air injection technology is an energy-effi cient, high-performance alternative to conventional sludge handling systems
SUPERIOR ENERGY SAVINGS During the trial, energy use and discharge pressure measurements were taken. Using these fi gures, together with the volume and height of the discharge pipework, Seepex engineers could then calculate the optimum amount of air required. T e trial concluded the energy saving with SAI compared to a multistage PC pump without air injection was 15%. Compared to the original piston pumps, the energy saving was an astonishing 61%. However, there were even greater savings to be made by switching to a single stage SAI pump fi tted with Seepex’s smart conveying technology (SCT), instead of the multistage pumps currently in use. Air usage data from a working SAI installation using SCT pumps in Belgium, enabled the fi rm to produce an estimate for T ames Water, based on the trial results from Reading. It concluded that, if SCT single
stage pumps were used in place of multistage pumps, the energy saving at Reading STW would be approximately 40%. When compared to the original piston pumps, an SAI system with SCT pumps would reduce energy consumption on this application by approximately 75%. SCT pumps deliver a range of other
benefi ts, too: reduced investment costs; longer service intervals; lower maintenance costs; smaller pump footprint; maintain in place capability; and long-distance transfer of non-fl owable products. As a result of the successful Reading trial,
T ames Water has procured several of the SAI units for its Riverside project. “We were faced with a particularly tough challenge at Riverside,” explains Paul Fountain, senior consultant – Biosolids, for T ames Water. “Replacing a problematic conveyor system with proven PC pumps was the preferred solution, but due to very tight space constraints, low access walkways and a labyrinth of pipework to work around, the traditional multi-stage pump was not going to be possible. “We decided to purchase several single stage SCT PC pumps, coupled with SAI innovation,” continues Fountain. “T is allowed us to reduce the pump length and installed motor powers, and has the added benefi t of ease of maintenance.”
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