Water and Effluent Treatment Magazine
Issue link: https://fhpublishing.uberflip.com/i/671821
12 WET NEWS MAY 2016 ONSITE DrAinAge TECHKNOW • A mix of Super Wispaset 100mm and Super Wispaset 150mm silenced pumps were used to pump water away • The Super Wispaset 100 can pump 45l/s and the Super Wispaset 150s can pump 90l/s • Both pumps operate at less than 65dBA at a distance of 7m • Bunded fuel tanks fed the pumps on site NEED TO KNOW 1 Lime content in the ground has posed a problem for network rail because of the impact it has on water management 2 Calcium carbonate deposit build-up on drainage channels, meant an increased risk of flooding 3 The pumps had to remain operational 24/7 throughout the project 4 The pipes were replaced using carrier drains formed from pre-cast open concrete units with grP mesh grid covers THE VERDICT With the over-pumping infrastructure in place, the QTS team could begin the water management improvements by replacing the existing 600mm twin wall carrier pipe with a PC concrete carrier. The pipes were replaced using pre-cast concrete carrier drains Keeping rail drainage improvements on track • network rail needed to install track drainage in the Peak District. But an over-pumping operation was essential for the project. Sykes Pumps' Chris graham explains. pROjECT SpECS • install new track drainage, including three new under track crossings • establish an over-pumping operation to ensure site safely • Provide equipment to comfortably handle potential flow rates of 550l/ sec • remove and replace the old drainage channels T he Peak District has a long history of quarrying and mining which can be seen in both the stonework of traditional homes and across the landscape. Some of the legacy of that industrial past can also be seen in waste mounds, and much of it is also hidden below ground in the form of restored quarry voids containing un-burnt lime- stone, ash, quick lime and slaked lime. It is that lime content in the ground that has posed a problem for Network Rail because of the impact it has on water management in an area known for high levels of rainfall. The hyper-alkaline (pH>9) lime in the soil has high concentrations of soluble calcium hydroxide which enters the water table causing heavy precipitation of calcium carbonate when the water absorbs atmospheric carbon dioxide. When these calcium carbonate deposits build up on drainage channels, it impedes the passage of water, leading to an increased risk of flooding. It is an issue that Network Rail needed to address to protect the railway sidings between the villages of Peak Dale and Dove Holes, near Buxton in Derbyshire. As a result, specialist rail contractor QTS Group was brought in to install new track drainage, including three new under track crossings (UTX), in a scheme that also included a sidings programme. QTS Group enlisted the help of Sykes Pumps to enable the over-pumping operation required to get the work done safely. Safe working While Network Rail already had an over-pumping operation at the site, this had been put in place to help manage the overflow caused by the calcium carbonate deposits that were effectively blocking the drainage channels. In order to take the old drainage channels out and replace them, the QTS team had to install an over-pumping system that would keep the site dry throughout the project, to enable both construction / engineering works and investigations that included a topographical survey, gauging sweeps, trial pits and automatic ballast sampling, with associated de-vegetation and an ecological and fauna survey. The Sykes Pumps team worked with the engineers