Hazardous effects of waste transformer oil and its prevention: A review

Transformer oil is the insulating oil that is utilized in power transformers for insulation and cooling during the operation of transformers. After a long run, the properties of the transformer oil such as breakdown voltage, and dielectric dissipation factor decrease to 32 kV, 0.41% while water content increases by 31 ppm resulting in waste oil. The disposal of waste transformer oil (WTO) is a big issue since it is contaminated with many virulent pollutants such as PCBs, PAHs, harmful gases, etc. which have adverse effects on the environment and living beings. Many scientists in this area studied to reduce its environmental impact and disposal problem by using different methods of recycling and re-use of WTO or re-refined into new transformer oil and also utilized in blended form with diesel fuel as an alternative fuel in diesel engines resulting in less smoke and hydrocarbon emission, increased BTE and NOx emission. In this review, we provide information about waste transformer oil, its toxic effects on the environment, the various techniques to recycle WTO, and its application in alternate fuels.