## Results and Discussion  
### Bioreactor Experiments  
This study was focused on the development of a new technology for the treatment of industrial wastewater polluted with hydrocarbons based on adsorption biodegradation processes. The biosorbent materials need to have efficient hydrocarbon retention, be easy to handle, not be expensive and be available in the market. According to these properties, cork sorb and propylene fiber sorbents were selected as a carrier to build the bioreactor (2018, 2019). Previously, the microcosm's assays demonstrated the ability of CorkSorbtm 01025, Pad Sentectm and Barrier Sentectm biosorbent to adhere to indigenous microorganisms from the polluted wastewater to the carriers' surface, making a stable biofilm (2018). In addition, it was observed that the higher the hydrocarbon content pollution was the more the microbiota adhered to the surface carrier, suggesting that the wastewater's indigenous microorganisms were tolerant of hydrocarbon pollution and could have a useful degrading capacity (2018). These assays were performed in vertical flow bioreactors, inside of which, sorbent materials were installed, taking up the entire section of bioreactor. The wastewater was recirculating from the bottom to the top of the bioreactor and the efficiency of treatment was monitored in terms of hydrocarbon removal from polluted water and the formation of biofilms on the surface carrier. When the industrial wastewater polluted with hydrocarbons was treated in the bioreactors, hydrocarbon content, regardless of the support material used, was almost totally removed. After 7 days, 92.6%, 97.5% and 94.5% of total petroleum hydrocarbons (TPHs) were removed from the bioreactor filled with Pad Sentectm, CorkSorbtm 01025 and Barrier Sentectm, respectively (Figure 2). Among them, the Pad Sentec(tm) bioreactor was the most efficient as the hydrocarbon removal was reached after the first cycle of recirculation. Table 2 shows the average of the initial hydrocarbon fractions concentration in the influent; while gas chromatography/Mass Spectrometry (GC/MS) analysis revealed that after one wastewater recirculation cycle, no hydrocarbon fraction was detected in the effluent. This suggests that, in the early stages of treatment, hydrocarbon removal was the result of a physical process of the support material combined with the microbial activity. In the case of the control assay, after 7 days of treatment there was a reduction in the TPH content by 20%, probably due to abiotic degradation processes. Results obtained demonstrate the high hydrocarbon retention capacity of the sorbent carriers employed. In addition, it can be suggested that this physical process was important at the beginning of the process but as the treatment was progressing, a biotransformation process was taking place in conjunction with hydrocarbon retention by the supporting material. In this sense, [PERSON] et al. [25] reported that the hydrocarbon absorption capacity of the meltblown polypropylene carriers was in the 7-9 g/gcarrier range, with a higher amount of hydrocarbon in the water to be treated. However, we observed an absorption capacity of only 0.04 and 0.07 g/gcarrier (53.2 and 109.4 mg/Lwater) for Pad Sentec(tm) and Barrier Sentec(tm) carriers, respectively. Gravimetric determination of TPH showed that the hydrocarbon content in the outlet wastewater after 7 days of treatment was 35.0 and 30.0 mg/Lwater, from 475.0 and 550.0 mg/Lwater in the inlet wastewater \begin{table}
\begin{tabular}{c c} \hline \hline
**Hydrocarbon Fraction** & **Average Concentration (ppm)** \\ \hline c10–c20 & \(145.6\pm 45.1\) \\ c20–c40 & \(14.6\pm 5.1\) \\ Branched/Cyclic alkanes & \(21.9\pm 6.4\) \\ Phytane & \(15.5\pm 4.0\) \\ Pristane & \(19.8\pm 7.3\) \\ Aromatics & \(10.4\pm 3.0\) \\ Alkenes & \(6.7\pm 3.8\) \\ Pregnanes & \(20.9\pm 6.8\) \\ Hahnfett & \(0.0\pm 0.0\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Average concentrations of hydrocarbon fractions in the influent wastewater before the start of the assays (initial time).