Water and Effluent Treatment Magazine
Issue link: https://fhpublishing.uberflip.com/i/831969
JUNE 2017 WET NEWS 15 needs a significant amount of land. However, the benefit is that neither chemicals nor electricity are required; aiding the environment and company budgets. An additional stumbling block has been the requirement for the sand used in filtration to be kept clean so that contamination does not occur and the optimum rate of flow through the filter is maintained. Now, thanks to new developments by processing companies such as my own, this is no longer an issue. High performance, high efficiency materials recovery and recycling systems have been developed to substantially reduce waste to landfill and maximise the production of commercial grade products, including sand, from a number of waste streams. These systems offer superior separation of lightweight and fine constituents, through a series of density separation techniques, ensuring the highest quality products can be extracted from waste material. Surface tension means that screening flowrates in more traditional static screens are reduced to what can be forced through the screen under pressure from the incoming material. However, new high- frequency screens use vibrations to move the screen. This breaks the surface tension and increases flowrates considerably. In traditional screening systems, blockages can occur if oversized material is forced against the static screening mesh blinding the screening apertures. This reduces efficiency, and before long, manual intervention is required. However, a high-frequency screen encourages material to be repeatedly li‚ed off the screening surface through the force of the vibrations; vastly reducing blinding. The vibrations also move material forward towards the discharge point. With vibrations 'conveying' screenings forward, there is no need for brushes or mechanical scrapers, removing a point of potential failure. With the prior concerns about flowrate and blinding removed, the specification of the screening size, and type, can be relaxed. This allows for two-dimensional screening (square apertures), rather than the spiral slots previously required to help achieve required flowrate. Within square aperture screening, larger particles are not allowed to pass through, preventing downstream issues. Missed opportunity The new screening technology means that a consistent supply of clean, dry filter sand, of uniform size and meeting all the requirements for slow sand filtration can be achieved, by extracting it from waste material or recycling the sand from the slow sand filtration system. For us, the slow sand filtration method remains the most effective way to ensure water quality, and it is a missed opportunity not to use it, when it offers so many benefits and solutions are now available to alleviate any problems that may have occurred. Developing and implementing new technology that is faster and smaller is o‚en the right thing to do if your business is going to achieve a competitive edge and reach its goals. We are not stuck in the past and many of our innovative solutions to clients' problems use new techniques and technologies. However, sometimes, speed really is not the essence and it is worth taking the time to achieve the right result. Ryan Jackson is project design engineer at waste management specialist CDEnviro. Ryan Jackson FOLLOW US SUPPORTED BY @WWTlive #DrinkingWaterQuality DRINKING WATER QUALITY CONFERENCE 2 NOVEMBER 2017 | BIRMINGHAM IMPROVING WATER QUALITY FROM SOURCE TO TAP An essential event for water quality professionals seeking innovative solutions to the regulatory and technical challenges facing the industry ● Hear a summary of the general annual report for water company performance from the Drinking Water Inspectorate ● Learn how to improve the technical elements of drinking water treatment ● Find new ways to mitigate customer-side risk and improve incident management Marcus Rink Chief inspector Drinking Water Inspectorate Heidi Mottram OBE Chief executive offi cer Northumbrian Water Group Ashlea Lane Director of water supply Wessex Water Dr Robin Price Head of water quality Anglian Water Elise Cartmell Chief scientist Scottish Water Chris Rockey Head of water quality South West Water Julie Spinks Managing director Water Regulations Advisory Scheme EXPERT SPEAKERS INCLUDE: BOOK NOW events.wwtonline.co.uk/ drinking IN ASSOCIATION WITH WWT-DrinkingWater-brochure.indd 1 17/05/2017 10:07