# Life Cycle Assessment of Different Waste Lubrication Oil Management Options in Serbia
## 3 Methodology
### Quantities of WLO in Serbia  
In 2010, the Regulation on Conditions, Manner, and Procedure of Waste Oil Management was adopted in the Republic of Serbia (RSerb). However, the participants' position in collecting, transporting, and processing waste oils is not clearly defined. The EU subsidies and taxes incentives received in recent years have often been awarded to dubious companies which do not have defined legal procedures for collecting, transporting, and treating oil. The Environmental Protection Agency of Serbia (EPAS) has access to completely different data compared to the Statistical Office of the Republic of Serbia (SORS), which also deals with WLO. The authors had great difficulty in obtaining relevant data on the quantities of WLO in Serbia. All data on the quantities of WLOs in Serbia used herein were obtained from the official institutions dealing with this issue. According to the EPAS data, a total of 38,654 (t) of lubricating oil are sold annually in Serbia. However, the unofficial data obtained from oil distributors, producers, and importers indicate that annual lubricate oil sales approximate to 54,000 (t) in the RSerb market. The authors wish to point out the major environmental problems that arise due to the uncollected WLO. The quantities of uncollected WLO are greater than those of treated oil and end up in unknown waste streams. Tables 1 and 2 show the annual quantities of new oils sold and WLOs collected and exported. \begin{table}
\begin{tabular}{l r r r r r r r r r} \hline \hline
**Source WLO** & \multicolumn{2}{c}{**2015**} & \multicolumn{2}{c}{**2016**} & \multicolumn{2}{c}{**2017**} & \multicolumn{2}{c}{**2018**} & \multicolumn{2}{c}{**2019**} \\ \hline  & **WLO** & **PCB\(*\)** & **WLO** & **PCB\(*\)** & **WLO** & **PCB\(*\)** & **WLO** & **PCB\(*\)** & **WLO** & **PCB\(*\)** \\ \hline Agriculture, & & & & & & & & & & \\ forestry, and & - & - & 163 & 3 & - & - & 111 & - & 68 & - \\ fisheries & & 97 & 0 & 139 & 17 & - & - & 2765 & 6 & 129 & 49 \\ Mining & & 2346 & 28 & 6447 & 35 & - & - & 4624 & 49 & 5444 & 47 \\ However supply & & & & & & & & & & \\ energy, gas, and & 399 & 6775 & 473 & 100 & - & - & 286 & - & 323 & - \\ steam & & & & & & & & & & \\ Water supply and & & & & & & & & & & \\ wastewater & 33 & 2 & 29 & 1 & - & - & 28 & 1 & 29 & 1 \\ management & & & & & & & & & & \\ Construction & 128 & - & 180 & 23 & - & - & 133 & - & 397 & - \\ Service sectors & 1681 & 1 & 1209 & 19 & - & - & 1817 & 1 & 1361 & 3 \\ In TOTAL & 4684 & 6806 & 8640 & 198 & - & - & 9764 & 57 & 7751 & 100 \\ \hline \hline \end{tabular}  
* PCs—waste oil with PCB  
\end{table} 
Table 1: Quantities of created WLO in (t) from 2015 to 2019 [27]. According to the results of [PERSON] et al. (2019), the process of PCB oil recycling can be performed well in cement kilns. Cement kilns were found to develop a sufficiently high combustion temperature to burn WLO with an acceptable emission of pollutants, thus polluting the environment less than other technologies. Figure 3 shows the ratios between untreated, treated, and exported quantities of WLO and the amounts of new lubricating oil placed on the market. According to the data of the Agency of the RSFb (27,28), the amounts of dangerous PCBs have been decreasing for years. Significant PSB quantities of 6806 tons were destroyed, especially after 2015. Thereafter, those quantities have ranged between 50 and 100 tons per year. The difference between the amounts of oil placed on the Serbian market (new oil) annually and the treated, untreated and exported WLO is most alarming. Table 2 and Figure 3 show the quantities of (new) oil placed on the Serbian market and the quantities of oil that were treated, exported and untreated. Of particular concern are the quantities of untreated oil recorded in 2019, which are almost double in value compared to the previous ones. It is known that of the total amount of oils placed on the market, 55 to 60% of oils are engine oils ([PERSON] et al., 2019).