# Pilot-Scale Fenton-like System for Wastewater Treatment Using Iron Mud Carbon Catalyst
## 4 Conclusions  
In this study, the FSC/Fe(VI)/H\({}_{2}\)O\({}_{2}\) system was used in the pilot test, which realized the efficient degradation of COD in the actual wastewater and had higher economic benefits. Specifically, the FSC/Fe(VI)/H\({}_{2}\)O\({}_{2}\) system was applied in the pilot scale, and the degradation rate of COD could be up to 64.59% in a neutral environment (pH = 6.5 \(\pm\) 0.5). Meanwhile, the COD in the effluent reached the Standard within 65 days. In addition, the abundant Fe0 and C=O groups on the surface of FSC promote the activation of Fe(VI) and H\({}_{2}\)O\({}_{2}\). Fe(IV) and \({}^{1}\)O\({}_{2}\) were the main active species in the degradation process. The cost per ton of wastewater treated in the FSC/Fe(VI)/H\({}_{2}\)O\({}_{2}\) system is 0.6209 USD/t. The FSC/Fe(VI)/H\({}_{2}\)O\({}_{2}\) system has stability and operability on a pilot scale and has a wide application prospect in the resource utilization of Fenton iron mud and wastewater treatment. In the future, the activity of the FSC can be recovered by thermal regeneration, further reducing costs. **Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app15158210/s1](https://www.mdpi.com/article/10.3390/app15158210/s1)]([https://www.mdpi.com/article/10.3390/app15158210/s1](https://www.mdpi.com/article/10.3390/app15158210/s1)), Figure SI: The Fe(IV)-oxo species at various pH conditions. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Water** & **Ferrous Iron** & **Sulfuric Acid** & **Hydrogen Peroxide** & **Lime** & **Sludge** \\
**Volume** & **(PPM)** & **(PPM)** & **(PPM)** & **(PPM)** & **(PPM)** \\ \hline
874 & 425.73 & 410.72 & 199.91 & 190.07 & 3.90 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Annual chemical consumption of sewage treatment plants for sewage treatment. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Technology**} & \multirow{2}{*}{**Technical Contrast**} & \multicolumn{4}{c}{**Economic Contrast**} \\ \cline{3-6}  & & **Pharmacy Name** & **Investment** & **Unit-Price** & **Prime Cost (USD/t)** & **Prime Cost (USD/t)** \\  & & & **Specifications** & **and Quantity** & **(USD/t)** & **of Sewage** \\ \hline \multirow{8}{*}{This technology} & \multirow{4}{*}{Strong oxidation} & H\({}_{2}\)O\({}_{2}\) & Technical grade & 169.83 mL/t & 904 & 0.1528 \\  & & FSC & Self-made & 1.48 kg/t & 68.95 & 0.0607 \\  & & Potassium ferrate & Technical grade & 37.13 g/t & 9000 & 0.3342 \\  & & Sulfuric acid & Technical grade & 98 mL/t & 400 & 0.06624 \\  & & Caustic patchs & Technical grade & 2.8 g/t & 2500 & 0.007 \\  & & Pwer consumption & - & kW-h & 0.75 & 0.2200 \\  & & Total & - & - & - & 0.8409 \\  & & & & & 199.91 g/t & 904 & 0.235 \\  & & & Ferisulfas & Technical grade & 425.73 g/t & 530 & 0.111 \\  & & Sulfur acid & Technical grade & 410.72 g/t & 400 & 0.244 \\  & & Calcium hydroxide & Technical grade & 190.07 g/t & 200 & 0.0349 \\  & & Chemical agents & polyacrylamide & Technical grade & 4.28 g/t & 1600 & 0.01261 \\  & & Acid conditions & Sludge disposal & - & - & - & 0.303 \\  & & Power consumption & - & kW-h & 0.75 & 0.1100 \\  & & Total & & & USD/(kW-h) & \\  & & & (USD/t of wastewater) & - & - & - & 1.0505 \\ \hline \multirow{8}{*}{Ozone technology} & Hard to remove & Liquid oxygen & Technical grade & 103 g/t & 720 & 0.7416 \\  & completely & Electric charge & - & 0.8848 & 0.75 & 0.6636 \\ \cline{1-1}  & Difficult to degrade & & & kW-h & USD/(kW-h) & \\ \cline{1-1}  & & organic matter & & & - & - & 1.4052 \\ \cline{1-1}  & Low utilization rate & Total & & & & \\ \cline{1-1}  & of ozone & & (USD/t of wastewater) & - & - & - & 1.4052 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Economic comparison of mainstream treatment technologies. **Author Contributions:** L.W. : Conceptualization, methodology, analysis, writing, review. L.L. : Formal analysis, writing--original draft, validation. J.X. : Methodology, writing--original draft. Y.W. : Software, investigation. B.Y.