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Wednesday, June 23, 2010 |
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Capping an Environmental Evil
:: News
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Source: Leon van der Merwe
Asbestos pollution, as is widely known, is dangerous to humans. Eskom is in the process of aggressively addressing environmental issues such as these on all their plants across South Africa.
Originally, when cooling towers were built the only option to distribute the hot water into the tower was through asbestos cement pipes containing small amounts of asbestos fibre. These have now been replaced with PVC pipes.
Each of the six cooling towers at the Camden Power Station yielded almost 40 ton of material containing some asbestos, leaving a lot of material to dispose of.
In line with the drive to rehabilitate existing asbestos dumps around the country, the Department of Environmental Affairs and Tourism has issued specific permit conditions for the rehabilitation of these dumps. Stefanutti Stocks recently rehabilitated the asbestos dump at Camden, in line with this permit.
The dump covered an area of 12 600m2 and was located adjacent to the ash dump. “Our first task was to clear all the vegetation on the dump,” said site agent Leronti Letoao. “We then imported about 4 000m3 of ash to level the area.”
Four 30-ton cement spreader trucks were then used to place 120 ton of cement on a daily basis for the stabilisation. Over 1 000 ton of cement was used for the entire project. We constructed a 500mm thick cement stabilised ashcrete layer (consisting of two layers of 250mm each), thus creating an impervious capping to the buried asbestos.
The last step was adding 100mm of topsoil over the capping layer in preparation for natural vegetation totake root.
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