## 3 Results and Discussion
### Cost Analysis of a Medium-Scale Photocatalytic System  
The economic viability of phenolic compound degradation was simulated using a magnetically recoverable BiOI/ Fe\({}_{3}\)O\({}_{4}\) photocatalyst. The Composite Parabolic Solar Concentrator (CPC)-type photocatalytic system was selected as a good option to achieve high percentages of photodegradation due to its reflective geometry [77], based on parabolic and involute sections to increase their efficiency (Figure 13). The CPC has great potential to be implemented in Pisco Endemico, given that this small industry generates a maximum amount of 1167 L/month of wastewater in its pisco production.  
The CPC collector will purify 40 L/day with a useful ground area of 3 m\({}^{2}\) in 180 min, data that are corroborated by [PERSON] et al. [39]. The heterogeneous photocatalysis system implies being a unitary primary post-treatment operation to improve the water quality physicochemical parameters and biodegradability indices, so that the treated effluent is compatible with a subsequent biological treatment [78].  
The photocatalytic system has a hydraulic pump with corrosion resistance of 70 L/min and 220 V, and an anodized aluminum CPC solar collector molded according to parabola and involute angles, allowing the installation of five 50 mm borosilicate glass tubes connected using PVC pipes, as shown in Figure 13a. It also has a magnetic separation unit. It considers adding 400 ppm of BF-5 to the continuous system for 180 min, which will be activated by solar radiation. In this way, a simple cost analysis was performed and tabulated in Table 3, following the methodology of [PERSON] et al. [41].  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Unit** & **Value** \\ \hline Chemical oxygen demand (COD) & mg/L & 11978 \\ Biochemical oxygen demand (BOD\({}_{5}\)) & mg/L & 2400 \\ BOD\({}_{5}\)/COD & - & 0.20 \\ pH & - & 3.73 \\ Turbidity & NTU & 309 \\ Electrical conductivity (EC) & mS/cm & 2.97 \\ Total suspended solids (TSS) & mg/L & 733.30 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Characterization of the Pisco Endemico tributary (measured in February 2024).  
Figure 13: (a) Photocatalytic system setup and (b) compound parabolic concentrator curve.  
According to the analysis, the treatment cost for removing pollutants with low biodegradability using magnetically recoverable BF-5 with a load of 400 mg/L is estimated at USD 16,178/h. In this case, the raw material for the manufacture of the photocatalyst contributed 80.67% of the total cost. Therefore, reducing these costs, such as replacing the solvent used in the synthesis of BF-5, will generate a significant fluctuation in the operating price in the near future. Cheaper syntheses should be investigated using the hydrothermal method (water and ethanol) to reduce operating costs to USD 4,234/h.  
By way of comparison, according to several studies [6; 79; 80; 81], one of the most effective methods to remove a high organic load with low biodegradability from vinasse wastewater is anaerobic membrane bioreactor (AnMBR) digestion. According to [PERSON] et al. [79], removing the BOD\({}_{5}\) and COD parameters in LIW comprising Vinasse using AnMBR would have a total cost of USD 271,405/h, higher than the USD 16,178/h to implement a photocatalytic system using BF-5. The high value of AnMBR can be attributed to what is indicated by [PERSON] et al. [82]. The authors argue that the main challenge lies in the high cost of the membranes and the substantial energy consumption associated with mitigating the membrane damage, despite the inherent energy advantages of anaerobic systems. Considering current systems' complexity and high costs, heterogeneous photocatalyst represents a promising solution for eliminating low-biodegradability organic compounds.