patents+technologies Used glass offers alternative to sand filter As part of the UK government's initiative, Waste Resources and Action Program...

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patents+technologies Used glass offers alternative to sand filter As part of the UK government's initiative, Waste Resources and Action Programme (WRAP), which is aimed at finding new ways to recycle used glass into high value products Dryden Aqua is currently developing filter media for purifying water that are made from recycled green and brown glass bottles. Many water treatment works employ the conventional method of filtering water through a sand bed to clean it. The rough and pitted surface of sand grains encourage the capture of bacteria and algae, but at the same time the grains can quickly become populated with microorgansims that cause the grains to clump together, and therefore reduce filtering efficiency. To ensure sand filters remain free of microbe contamination frequent, intensive flushing is required. The newly-developed filter media, known as Advanced Filtration Media (AFMC~), is made from used glass ground into fine particles.And unlike sand grains they have very smooth surfaces, so they do not capture particles in the same way as sand grains. Instead, they use two unique mechanisims that not only capture contaminants, but also destroys them. Firstly, during the grinding process molecular bonds are broken, which leaves spare electrons on the particles' surface. This means that the grains have a net negative charge, and therefore attract postively-charged particles. The grains also possess surface catalytic properties. Green and brown glass, are made by the addition of chromium and iron salts, respectively. Both metals possess catalytic activity, and can split oxygen

molecules into single highly-reactive oxygen radicals. Therefore filter media made from coloured glass first electrostatically draw microbes to the surface of the grains, where they then react with the oxygen radicals and are destroyed.

Research to improve filtration of minerals A collaborative research project aimed at improving the performance of filtration equipment used in the mineral industry is due to begin in Australia early next year. Coordinated by the Australian mineral industry's research association, AMIRA International Ltd, research teams at the Melbourne University and the Commonwealth Scientific & Industrial Research Organization (CSIRO) are currently preparing a detailed research proposal for a three-year project, which is expectecd to begin in January 2003. The research will be aimed at opening up the opportunities for improvements in filtration processes through a knowledge based system or improved process models. The initial task is to gain a better understanding of the various types of filters, and their operational dynamics. This will provide some of the key data to be the foundations of the CFD models. The eventual research programme is likely to be in three modules: Chemical Conditioning - Design and Optimization for Filtration; Application of Filtration Models to Industrial Practice; and Development of a Filtration Problem Resolver - a roadmap for finding solutions to filtration problems

Sunlight destroys environmental pollutants Researchers at the University of Nottingham, UK, have discovered an environmentally friendly way of removing micropollutants from the environment by combining a cheap, harmless chemical with sunlight. The research team, led by Dr Gianluca Li Puma, is investigating a novel type of reactor, called the 'fountain photo-catalytic reactor', to treat water containing persistant contaminants, such as pesticides and pharmaceutical residues. The reactor works by pumping the water through a specially designed nozzle, where titanium dioxide, an inexpensive white powder used as a pigment in paints and health products, is added. Titanium dioxide is also a powerful photo-catalyst, i.e. its uses the energy from sunlight to split molecules into free radicals. In water it creates the O H radical, which readily reacts with large carbonbased molecules, such as pesticides and converts them into carbon dioxide and water. The reactor's nozzle produces an umbrella-shaped fountain of water, with the sunlight (or artificial ultraviolet light) falling on the 'canopy' of the umbrella. This allows the titanium dioxide to absorb the solar radiation efficiently, resulting in a more effective destruction of the pollutants. Once the contaminants have been removed, the water can be passed to a settling tank, where the titanium dioxide is recovered and can be re-used for the same process. The team has successfully demonstrated the feasibility of the concept using a 400 litre pilot plant and ultraviolet lamps to simulate sunlight.

Patent Summaries Enhancing Filtration Yields in Tangential Flow Filtration, Scilog Inc, USA. WO 0 2 / 0 0 3 3 1 . Date of Publication: 03 January 2002.

Diesel Fuel Filter with Interchangeable Cartridge, Sogefi Filtration SpA, Italy. WO 0 2 / 0 6 6 6 2 . Date of Publication: 24 January 2002.

Method for Modifying Membrane Rejection Characteristics, Nirosoft Industries Ltd, Israel, WO 02/04082. Date of Publication: 17 January 2002.

Microfiltration Housing, Moulage Industriel de Perseigne "MIP", France. W0 0 2 / 0 7 8 5 6 . Date of Publication: 31 January 2002.

Method and Device for Carrying Out Membrane Purification, Creavis Gesellschaft Fur Technologie und Innovation, Germany. WO 0 2 / 0 5 9 3 6 . Date of Publication: 24 January 2002.

Method and Appartus for Treating Wastewater Using Membrane Filters, CH2M Hill, .USA. WO 0 2 / 1 0 0 7 7 . Date of Publication: 07 February 2002.


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