Water & Wastewater Treatment

www.wwtonline.co.uk | WWT | november 2014 | 21 The resmix 5000cc was in- stalled by helicop- ter, and situated at the deepest point of the reservoirs I nstalling a system which de- stratifies Pontsticill Reservoir has allowed Dŵr Cymru Welsh Water to tackle water quality issues and allowed proactive management of its water resource. This summer the company invested £1.5M in improvements at Pontsti- cill, which is located in the Brecon Beacons, north of Merthyr Tydfil. Around £1M of this was spent on the installation of a system - the ResMix 5000cc – which it is hoped will prove the key to ensuring the drinking water originating from the reservoir is more consistently pleasant tasting in the years to come. In recent times the reservoir has had periodic problems with meth- ylisoborneol (MIB) a compound resulting from algae growth, which is particularly prevalent in the summer months. While not a health risk, MIB can give water a musty smell and taste, and requires additional treat- ment processes to eliminate. "In 2011/12 we started experiencing taste and odour issues coming from the Pontsticill reservoir," says Geraint Long, solutions manager at Dŵr Cymru Welsh Water. "We looked at a few different solutions: the normal solution to that would have been a GAC [granular activated carbon] type installation, which is high opex cost and high capital cost to put in place. "But on-site at Pontsticill there was limited space and we really had Water resources Reservoir system tastes sweet for Welsh Water limited options. "So we started looking at the root cause of where we were finding issues, the MIB which was in the reservoir, and whether we could do anything to manage our reservoir source more ef- fectively to reduce the taste and odour issues further down the line." Stratification challenge Dating from 1927, Pontsticill reservoir holds over 15 billion litres of water – equivalent to 6,000 Olympic sized swimming pools. Part of the reason algae was flourishing in the resource was stratification – the process by Project focus ● £1m investment tackles high mIb levels resulting from algae growth ● ResMix system installed to prevent stratification problems ● Largest such system installed in northern Hemisphere JameS Brockett edITor, WaTer & WasTeWaTer TreaTmenT ● algae growth in Pontsticill reservoir was leading to high methylisoborneol (mIB) levels in the water supply, resulting in taste and odour issues, especially in the summer ● removing the mIB in the treatment phase would have required multi- million pound investment ● Installing equipment to de-stratify the reservoir was a cheaper, low energy solution • Drivers • Innovations ● It is the first time the resmix 5000cc, the biggest system manufac- tured by WearS austral- ia, has been used in the Northern Hemisphere ● Installation was by helicopter, for ease of ac- cess and improved safety ● System can be run 24 hours a day but uses one-twentieth of the energy of compressed air alternatives

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