Microbial Contamination of Electrical Power Transformer Oil Obtained from Onitsha, Nigeria

Abstract

Microbial contamination of in-use and unused electrical power transformer oils obtained from Onitsha, Nigeria was studied using cultural techniques. The average bacterial and fungal counts of the in-use oil were 1.2 x 10 2 cfu/ml and 0.7 x 10 2 cfu/ml respectively while the mean bacterial and fungal counts of the unused oil were 0.5 x 10 2 cfu/ml and 0.3 x 10 2 cfu/ml respectively. The microorganisms from the in-use oil were Micrococcus luteus, Pseudomonas aeruginosa, Serratia marcescens, Corynebacterium bovis, Bacillus subtilis, Klebsiella aerogenes, Aspergillus niger, Aspergillus flavus and Mucor pusillus while those from the unused oil were Micrococcus luteus, Serratia marcescens, Bacillus subtilis, Klebsiella aerogenes and Aspergillus fumigatus. Bacillus subtilis occurred most frequently in both oils. The P H of the medium decreased to the acidic level while there was an increase in the viable counts, indicating the utilization of the transformer oils by the isolates. These isolates may cause the deterioration in the oils quality leading to the failure of the transformer with its attendant economic losses. Regular inspection and maintenance of the transformer as well as periodic changing of its oil is recommended to curb the economic losses.

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