www.swimmingpoolnews.co.uk
FiltrationMedia DEC 2011 SPN
53
NEW WATER TREATMENT RESEARCH REVEALS A MAJOR BREAKTHROUGH
Leading environmental and water treatment experts Dryden Aqua say their work on activated glass filtration media is set to bring new levels of safety to pool water treatment – bringing with it not only health benefits but savings to pools and less damage to systems and buildings. A seminar in Switzerland in March will present the findings but in a special report we highlight the key developments and research which has been carried out
ver the last 15 years Dryden Aqua have been analysing and modelling swimming pool water treatment systems to determine the mechanisms by which chlorine reaction products are formed. “It is only once you have an understanding of the biology, chemistry and mechanics of the process is it possible to optimise the water treatment systems. We are now approaching the conclusion of pool water treatment,” says Dr Howard Dryden.
O
“The elimination of chlorine by-products is essential for the health of the public, especially young children and the staff that work in swimming pools. It also makes economic sense, the less chlorine and water used, the lower the operating costs, and less damage will be inflicted on the building and ventilation systems by stress corrosion cracking,” he adds.
AFM THE ACTIVE FILTER MEDIA All systems using sand filters, either on their own or in combination with UV or ozone are biological processes that depend on the action of bacteria in the filter to remove urea, ammonium and other dissolved organic matter. Combined chlorine problems may be solved using UV but
nitrogenous disinfection by-products (N-DBPs), such as nitrosamines, cyanogen chloride may be formed and these are more dangerous than combined chlorine because they are genotoxic and cytotoxic.
Diatomaceous (DE) or perlite filters are not biological, but because coagulation and flocculation cannot be used without blocking the filter cake, the water will have a higher concentration of dissolved organic matter and urea. The dissolved chemicals can be removed by chlorine oxidation, but this generates high combined chlorine. If the organics are not oxidised by the chlorine they will act as a food source for bacteria which again gives high combined chlorine and potential bio-hazard. It is almost impossible to eliminate the biohazard associated with sand or DE filtration systems, or the production of disinfection by-products. Dryden Aqua developed AFM which is an activated glass filtration media. Other companies have tried to develop their own glass filtration media. The company invested 1.2m euros in research in co-operation with the European Commission to develop a glass filter media which has similar properties to self- cleaning glass windows.
“The elimination of chlorine by-products is essential for the health of the public, especially young children and the staff that work in swimming pools”
AFM is not a recycled product, a high percentage of the glass is manufactured by Dryden Aqua
AFM is not a recycled product, a high percentage of the glass is manufactured by Dryden Aqua and a proportion is recycled. The material is then subjected to an activation process and coupled with the high purity and particle size and shape; this gives AFM its high performance. Independent tests comparing sand and crushed glass conducted over the last 12 months have confirmed sand performs better than a basic crushed glass, and you avoid the risks associated with crushed glass causing eye and skin damage to the bathers.
Independent trials conducted by a French National Government organisation over the last six months between AFM and one of the better crushed glass products again confirmed the far superior performance of AFM. The trial had to be cut short because the crushed glass filter was
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92