Water & Wastewater Treatment

14 | MAY 2014 | WWT | www.wwtonline.co.uk Project focus: Mobile treatment at a greater rate than using tank- ers, while minimising the impact of the flows on the environment and reducing tanker road move- ments – something which can have an impact on local communities, particularly small villages. There is also a substantial cost benefit. "At the peak of our work to tackle flooding, we were spending in excess of £100,000 a day on tankers and over-pumping, and most of that on tankering," says Paul Kent, Asset Strategy Manager, Southern Water. "Commissioned, fitted with strainers, and operating 24/7, these mobile units cost around £25,000 each, so it does not take long to recover the capital costs of the equipment," he says. Southern Water purchased ten units, initially used to alleviate the impact of groundwater flooding on its sewers and sufficient for current needs, Kent says. As water levels subside these units will be decommissioned progressively and transfer to support wastewater treatment works. "We will keep under review how many of these portable units we need in the future," he says. The Environment Agency has also expressed interest in Southern Wa- ter's mobile treatment solution. "It is something the EA are very interested in," says Kent. "As we take more and more samples and understand the efficiency, we will be sharing results with the EA so that they can see the benefits of the units." "It may be a route other companies reliant on over-pumping could go down. We are more than happy to share our experience." Kent says. For further reading go to wwtonline.co.uk "It may be a route other companies reliant on over- pumping could go down. We are more than happy to share our experience" Paul Kent • Lessons learned The portable treat- ment units have worked exceptionally well so far, says Palmer, However, as with any new design there have been some lessons learned on the units, with some small details that will be changed if Southern Water builds more. "Initially we put small, fixed strainers on the sides of the units to ensure we did not clog the filter. However, because of the amount of material in sewers, the small strainers blocked quickly. We had expected a daily service routine – we have to tend the pump attached to the tank daily to refuel and service it – but in opera- tion we needed to extend that period. We construct- ed larger strainers fitted to the end of the pumps sucking flows from man- holes and that's given us four days without the need for maintenance work," he says. "When we built the units we consciously designed them for operation in areas without power, such as roadsides and within fields. It meant we kept away from anything that had powered equipment, avoiding the need for gen- erators. It is deliberately a very simple design, com- pletely self-contained with little maintenance other than cleaning the strainer and refuelling the associ- ated pump or pumps on a daily or so visit." "There is still an ongoing debate about the need for walkways on the units to help with maintenance. However, we deliberately kept these off the units, bearing in mind the prob- able public siting of the equipment, to discourage unwanted visitors climb- ing on the tanks." • Challenges 2 ● One of the challenges Southern Water faced is a highly visible presence in Kent and Hampshire tackling the impact of groundwater flooding on its sewer network. Not only is it necessary to do a lot of ground work to gain access for tanker operations, but it is also important to inform local politicians and the public about what is being done and why equipment, such as the mobile treatment units, are being used. Southern Water pro-actively briefed local stakeholders, such as MPs and councillors, and actively involved regional television and newspapers to explain the merits of its mobile treatment units,gaining good coverage locally. Top: Craning units into place near Canterbury, Kent. Bottom: Positive publicity for the new units gained from active engagement with local media Knowledgeable Staff We value experience and training FOR MORE INFORMATION VISIT www.burdens.co.uk We recognise that our most important resource is our people. Our customers appreciate the vital contribution Burdens staff make to their working relationship by bringing in-depth product knowledge as well as a huge wealth of experience to every job. Specialists in Below Ground Drainage for Civils and Utilities J13-096 Burdens_adverts for WWT_210x297_v05.indd 3 11/02/2014 17:15

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