Investigating the Quantity of Used Oil Produced by Motor Vehicles in Iran and Providing Management Solutions Based on Health and Environmental Principles

Background. Used oil is a problematic waste containing hazardous and toxic components. This study aimed to investigate the quantity of used oil produced by motor vehicles in Iran and offer management solutions based on health and environmental principles. Methods. First, the conversion ratio of motor oil into used oil was determined. The mass balance method and the conversion ratio were used to estimate the used oil produced in the past 14 years. The amount of used oil produced over the following 15 years was also predicted using an artificial neural network. The current status of used oil management in Iran was assessed through checklists, observations, field visits, and interviews. Finally, an appropriate management solution was provided for it. Results. According to the results, 151.2 to 315.2 kilotons (kt) of used oil were produced annually in Iran between 2003 to 2017, and it would reach 250 kt by 2031 according to prediction. In Iran, approximately 77% of the used oil was collected and recycled, about 5% was used in construction, and the rest was disposed and managed without following the scientific principles. Conclusion. The lack of principled management of used oil may have had a significant adverse impact on the environment. Taking into account the fact that about 55% of used oil was produced by vehicles, and assuming that the remaining 45% of used oil was produced by other sources, it was concluded that the overall percentage of used oil production in Iran was probably two-fold approximately. Therefore, it was recommended that the current situation and its principled management should be minitored.