Water & Wastewater Treatment

WATER TREATMENT £5M filter media plant opens in Scotland Dryden Aqua's new AFM manufacturing plant near Edinburgh The opening of a £5M glass-processing plant to manufacture activated filter media in Scotland is helping Dryden Aqua meet global demand. However, says managing director Howard Dryden, uptake in the UK is lagging behind. Freelance reporter Claire Smith made a visit to the facility to find out more about the company's global and UK ambitions G iant models of a dolphin, a starfish and an angelfish decorate the conference room at Dryden Aqua's new manufacturing plant near Edinburgh. Entrepreneur and inventor Howard Dryden began life as a marine biologist, which is how he first became interested in the business of filtering water. After doing a PhD on sand filters in closedsystem aquaculture, Dr Dryden created an artificial filter medium from re-engineered recycled glass. His new plant in Bonnyrigg, Midlothian can produce 40,000t/year of activated filter media (AFM). The product is used in public aquariums around the world, in swimming pools across Europe and has just been ordered for a water treatment works in China, for a city with a population of 1.2M. AFM is being built into water filtration systems in places such as India and Israel and Dryden Aqua is a big player in the European swimming pool market - with 80% of Swiss pools and 20% of those in the Netherlands using the product. Global installations The company believes there are now 100,000 water treatment systems around the world which use AFM instead of sand. However, 90% of all its orders go abroad and Dryden has been frustrated by the lack of interest from the water industry in the UK - although he says replacing sand filters with AFM can dramatically improve drinking water quality and can reduce the need for the addition of chemicals. He says, "The UK water industry is very riskaverse and very slow to adopt new technology. If you are a small-to-medium enterprise - that can be hard. "For a small company to get involved with the water industry is very difficult. Most of our contracts with the water industry have been in the middle east and Asia." The development of AFM originally grew from Dryden's research into aquaculture. Fish farms which recycle water in closed systems have to have extremely efficient methods of filtering out bacteria in order to keep fish healthy. After working with zeolytic sand engineered to repel bacteria - the biologist started to research alternatives - and was awarded a £1.2M EC grant to look into ways of processing glass to create a substance which would not just filter but actively absorb certain sorts of molecules. After 30 years of research and development, the inventor is a passionate advocate for his product - which he says has many advantages over traditional sand. "No two sands are the same, but with AFM you know exactly what you are getting. We can improve the quality of water by 50% - reducing the need for additional chlorine and flocculent and saving water companies' money." Dryden Aqua officially opened a new £5M manufacturing plant in Bonnyrigg, Midlothian, in December 2013. The factory, which is completely computer-operated, is already running smoothly. Glass recycling Against the outside walls of the plant lies a huge pile of broken recycled green grass - which is the raw material for the product. Inside the factory the glass is ground and broken up into smooth, sand-like particles, then treated using heat and chemicals in a secret process. The three-stage process alters the molecular structure of the glass particles, 16 Water & Wastewater Treatment January 2014 "The UK water industry is very risk-averse and very slow to adopt new technology. If you are a small-to-medium enterprise - that can be hard." making it resistant to bacteria and less prone to coagulate. The surface area of the glass particles becomes three hundred times as great - taking it to more than 1Mm2/t. The re-engineered glass has an increased negative charge and extra metal oxide catalysts and can be tailor-made to remove specific substances such as arsenic, fluoride and chromium. At an onsite laboratory, researchers are looking at other ways to engineer the product to target different kinds of pollutants. Bagged up by robot packers, the finished material is light green, sparkling and surprisingly soft and smooth to touch. Large white sacks of the green magic media are bagged up and labelled for delivery - the current batch is destined for Tel Aviv. Although 90% of the material produced by the plant is currently exported - Dryden believes that will

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