WET News

OCTOBER 2014 WET NEWS 25 Consideration should be given to systems that can cope with very low load- ings and shock loadings. A solution: Sizing and speciing off-mains products A s has been indicated ear- lier, commercial pump stations such as the King- span Klargester Pumpstor, offer the option of a connection to the sewer for properties where grav- ity cannot be relied on. There are two principle regu- lations dictating design and use of pump stations – Building Regulations H1 and British Standard EN 752-6. Section H1 of Building Regulations for Foul Drainage details the need for 24 hours of foul storage within the pump station in case power supplies fail. BS EN 752-6 gives general design guidance for package pump stations. When specifying a pump sta- tion the following is important to understand: • The height and distance from the product to the main sewer if pumping directly to it • The depth of the incoming drain • The type of liquid that needs to be pumped and • The type and number of users Most commonly, people mis- calculate the depth of the incoming drain and fail to accu- rately measure the distance and height to the main sewer into which they're planning to pump. Another important issue is the electrical capacity of the property. If the main drain is a significant distance away from the property then three phase electricity could be needed. Pump stations operated by sin- gle phase electricity are best suited to small developments. Private drainage options If pumping effluent to the main sewer proves too difficult because it is too far away or access is problematic then sew- age will need to be dealt with inside the boundaries of the property. Sewage treatment plants such as the Kingspan Klargeser Envirosafe should be consid- ered as the preferred, default • Maximises permissible downstream flows • Adjustable to + 30% from design flow • Minimises upstream storage through constant discharge • Simplifying design and construction of dam structures • Manufactured to meet any design requirements • Non-powered mechanical control • Included in Micro Drainage software Speak to us about our HydroSlide Flow Control HydroSlide Flow Control Regulators Regulators www.hydrok.co.uk 01726 861900 sales@hydrok.co.uk The family of HydroSlide flow regulators accurately control discharge flows to +/- 5% throughout the impounding head range enabling optimum discharge of the storage system. This reduces the footprint of the required storage to a minimum and saving on land and construction costs. Hy- droSlides can be configured to provide varying 'stepped' flow rates to cater for discharge from in- creasing storm return flow outputs, further optimising tank design. A proven cost effective technique for controlling flows and alleviating flooding: Hydrok Flooding 10.14:WET News 19/08/2014 13:32 Page 1 Stormwater Solutions Turning Water Around... ® For further information call the Hydro-Brake ® hotline: 01275 337937 or visit www.hydro-int.com Try the design tool at: www.hydrobrakeoptimum.com Hydro-Brake Optimum ® Design Tool A software tool to help engineers fine-tune surface water flood prevention Generates dimensioned drawings and hydraulic modelling data outputs. Registered charity numbers 288701 (England and Wales) and SC039479 (Scotland) WaterAid/GMB Akash/Panos Learn how your company can help WaterAid reach 25 million people with safe water and sanitation by 2015. Email us at waterindustry@wateraid.org 25 million. www.wateraid.org Generic WIP Ad A4 portrait.indd 1 06/11/2013 10:18:35 Blowers, Screw Blowers and Turbos for Aeration Oil-free energy efficient solutions A range of machines to ensure optimal capital and whole life cost solutions High reliability Extensive water industry experience Aerzen Machines Ltd Compressed Air, Gas and Vaccuum solutions, Sales, Service, Maintenance and Rental +44 (0) 208 502 8100 sales@aerzen.co.uk www.aerzen.co.uk solution; they provide an envi- ronment where aerobic bacteria can break down sewage and are highly efficient, treating more than 90% of the pollutants. Packaged sewage treatment systems with tertiary treatment such as packaged reed beds are the current 'gold standard', bringing the efficiency rating up to 98%. They produce a clear overflow that is environmentally friendly and suitable for dis- charging even on sensitive sites. Effluent from an sewage treatment plant is allowed to discharge into a watercourse, but this is regulated and may require registration with the Environment Agency / Environ- mental Protection Agency. Applications for discharges can be made online, but always seek advice first. Sizing a sewage treatment plant Commercial waste can vary greatly from one site to the next in terms of quantity, flows, load- ing, and concentration of solids, ammonia and biological oxygen demand (BOD). British Water's Flows and Loads code of practice is invalu- able reading for system design- ers, providing help in calculat- ing daily sewage loading, plus advice on the nature of the sew- age to be treated, and anything which may affect treatability and system performance. If we consider a campsite scenario, then there are static as well as touring caravans, tents, as well as full and part time staff to consider. Consideration should be given to systems such as the Envirosafe that can cope with very low loadings and shock loadings as well as prolonged periods of shut-down. The sewage strength from the cocktail of detergents, cleaners, and chemicals in com- mercial applications demands a greater treatment capacity than a purely residential application. n Geoff Oakley is technical sales manager at Kingspan Klargester

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