## 3 Applications and Limits of ATPs in Water and Wastewater Treatment
### Applications of ATPs in Water and Wastewater Treatment
\begin{table}
\begin{tabular}{l l l} \hline \multicolumn{1}{c}{**Contaminant**} & \multicolumn{1}{c}{**Type of Process**} & \multicolumn{1}{c}{**Remarks/Results**} \\ \hline
2,4,6-trinitrotoluene & Electro-Fenton & Nearly complete TOC mineralization \\ \hline
4-Chlorobenzoic acid & Electrolysis-ozonation & Complete degradation after 30 min \\ \hline Aniline, nitrobenzene, 4-chlorophenol & Photoelectro-Fenton (electrolysis and UVA) & Nearly complete mineralization after 50 min \\ \hline \multicolumn{1}{c}{_Dyes_} \\ \hline Diacryl Red X-GRL & Photolysis & 70\% degradation in 5 h \\ \hline CI Reactive Yellow 145 & UV/O\({}_{3}\) & 80\% TOC removal in 2.5 h with 175 W UV irradiation \\ \hline Rhodamine B & UV/H\({}_{2}\)O\({}_{2}\) & 73\% decoloration achieved \\ \hline CI Reactive Black 5 & Photocatalysis (UV + SrTiO\({}_{3}\)/CeO\({}_{2}\)) & Complete decolorization after 120 min, 57\% TOC removal in 5 h at pH = 12.0 \\ \hline Acid Orange 7 & Photocatalysis (UV/TiO\({}_{2}\)) & 90\% reduction after 4-h \\ \hline CI Direct Red 23 & Ultrasound/O\({}_{3}\) & 98\% removal after 1 min \\ \hline CI Reactive Blue 19 & Ultrasound/O\({}_{3}\) & 65\% TOC removed in 2 h \\ \hline Crystal violet & Homogeneous Fenton (Fe\({}^{2+}\)/Fe\({}^{3+}\) + H\({}_{2}\)O\({}_{2}\)) & Complete degradation after 10 min at pH = 3 \\ \hline Orange II & Heterogeneous Fenton (FeVO\({}_{4}\) + H\({}_{2}\)O\({}_{2}\)) & 94.2\% degradation in 60 min \\ \hline Levafix Blue CA, Levafix Red CA & Electro-Fenton & Complete decolorization and 90–95\% mineralization achieved \\ \hline \multicolumn{1}{c}{_Pharmaceutical compounds_} \\ \hline Amoxicillin, ampicillin, & Photo-Fenton & Complete degradation of antibiotics in 2 min \\ \hline Paracetamol & Photocatalysis (UV/TiO\({}_{2}\)) & \textgreater{}80\% degradation in 5 h \\ Triclosan & Sonolysis & Complete degradation \\ \hline Levodopa, paracetamol & Sonolysis & At initial concentration of 25 mg/L, 91\% levodopa, 95\% paracetamol removed in 4 h \\ \hline Ibuprofen & Electron-Fenton, UVA and solar & Solar photoelectron-Fenton achieved \\  & photoelectro-Fenton & highest mineralization (92\%) \\ \hline Propranolol & Ozonation & Nearly all antibacterial compounds \\ \hline Antibacterial compounds & Ozonation & quantitatively deactivated \\ \hline \multicolumn{1}{c}{_Pesticides_} \\ \hline Linuron & Photocatalysis (TiO\({}_{2}\)/H\({}_{2}\)O\({}_{2}\)/visible light) & \textgreater{}70\% decomposition \\  & Photolysis & 91\% degradation after 16-h irradiation \\ \hline
2,4-dichlorophenoxyacyacetic & Sonolysis & 90\% degradation in 100 min \\ Acid & Ozonation (30 mg/L) with MnO\({}_{x}\)/MZIW & 82\% TOC removal at pH = 3.7 \\ \hline Methamidophos & Anoxic oxidation with Si/BDD & Complete mineralization \\  & electrodes & \\ \hline Atrazine & Photoelectrocatalysis & Complete removal \\ \hline Diuron & Photolysis & 88\% degradation after 16-h irradiation \\ \hline Chlorotoluron & Photolysis & 71\% degradation after 16 h \\ \hline Pesticide mix (alachlor, & \multicolumn{1}{c}{} & \\ atrazine, chlorofenvinphos, & Solar photo-Fenton & All pesticides mineralized after 12–25 min \\ diuron, isoproturon & \multicolumn{1}{c}{} & \\ \hline \end{tabular}
\end{table} 
Table 6: _Cont._As it can be seen from Table 6, most conventional AOPs may require extended process times for contaminants' degradation, ranging from a fraction to several hours to achieve at least a _1-log_ reduction of the original contaminants' mass. It may also be noticed that, when reporting the results of their studies, researchers refer to the fate of the primary target contaminant with the words \"removed\", \"degraded\", or \"decomposed\" without specifying (save for rare occasions) if the actual contaminant's \"end-of-life\" (i.e., mineralization) was reached, or the nature of the degradation products.