Abstract

Eucalyptus hybrid, Mangifera indica and Melia azedarach were treated with different concentrations of CCA, ACA and Copper lignate. Pinus roxburghii (Pine) was also treated with the same preservatives and used as reference species. Two experiments for different periods i.e. 4 and 5 years were conducted in the same cooling tower. Observations in terms of weight loss were taken. It was found that Melia azedarach (Melia), Pinus roxburghii and Eucalyptus hybrid (Eucalyptus) performed excellently when treated with CCA at 16 kg/m3 retention throughout the period of investigation. While ACA (16 kg/m3) and CCA (i) (consisting As2O3.2H2O) treated samples were protected considerably but were not comparable with CCA treated samples. Copper lignate (1.0, 1.5 and 2.0 kg/m3) treated samples (10 x 2.5 x 0.6 cm3) of all species, could not perform satisfactorily. Visual observations of Mangifera indica (Mango) samples indicated heavy attack of soft rot fungus on the sample in the 3rd year of experiment itself, thus indicating none of the preservative treatment being able to protect Mango wood samples. Thus, Eucalyptus hybrid (heartwood) and Melia azedarach  treated with CCA can be recommended for smaller size samples used in cooling towers whereas for bigger size of wood used in cooling towers, where strength is important criteria, bigger samples i.e. stake test (45 x 5 x 4 cm3)  is required.

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