## 3 Results  
### Organic Compounds  
S2V1 had the lowest level of COD. Effluent from the MW-heated reactors contained, on average, 0.30 \(\pm\) 0.07 gO\({}_{2}\)/dm\({}^{3}\) in SER2 (55 \({}^{\circ}\)C) and 0.38 \(\pm\) 0.10 gO\({}_{2}\)/dm\({}^{3}\) in SER1 (35 \({}^{\circ}\)C) (Table 4, Figure 2a). The corresponding COD removal rates were 97.8 \(\pm\) 0.6% and 98.1 \(\pm\) 0.4%, respectively (Table 4, Figure 2b). S1 (C) had significantly higher COD. The SER1 (35 \({}^{\circ}\)C) effluent contained 0.68 \(\pm\) 0.08 g O\({}_{2}\)/dm\({}^{3}\), whereas SER2 (55 \({}^{\circ}\)C) effluent had 0.37 \(\pm\) 0.05 gO\({}_{2}\)/dm\({}^{3}\) (Table 4, Figure 2a). Removal rates were 95.7 \(\pm\) 0.5% and 97.7 \(\pm\) 0.3%, respectively (Table 4, Figure 2b). Increasing the OLR to 2.0 gCOD/dm\({}^{3}\)-d (V2) led to a parallel increase in the effluent COD. The lowest COD values within V2 were noted in S2 (MW) at 0.80 \(\pm\) 0.06 gO\({}_{2}\)/dm\({}^{3}\) (SER1/35 \({}^{\circ}\)C) and 0.62 \(\pm\) 0.03 gO\({}_{2}\)/dm\({}^{3}\) (SER2/55 \({}^{\circ}\)C) (Table 4, Figure 2a). This translated to COD removal rates of 95.0 \(\pm\) 0.4% in SER1 and 96.1 \(\pm\) 0.2% in SER2 (Table 4, Figure 2b). Effluent COD in S1 SER1 was 1.21 \(\pm\) 0.09 gO\({}_{2}\)/dm\({}^{3}\) (Table 4, Figure 2a), at a removal rate of 92.4 \(\pm\) 0.5% (Table 4, Figure 2b). The results for S1 SER2 (55 \({}^{\circ}\)C) were comparable to S2 SER2, with COD levels of 0.66 \(\pm\) 0.05 gO\({}_{2}\)/dm\({}  
levels in the final effluents were fairly similar, with only nonsignificant differences. The lowest COD value was 12.35 \(\pm\) 0.98 g O\({}_{2}\)/dm\({}^{3}\) (S2 SER2), whereas the highest one peaked at 14.31 \(\pm\) 2.66 g O\({}_{2}\)/dm\({}^{3}\) (S1 SER1) (Table 4, Figure 2a). This means that S2 SER2 (55 \({}^{\circ}\)C) performed the best in terms of COD removal (22.8 \(\pm\) 6.1%) (Table 4, Figure 2b). Similar trends were observed for TOC. SER2V1 (both stages) had the lowest TOC levels in the effluent at 0.06 \(\pm\) 0.01 g/dm\({}^{3}\) (Table 4, Figure 3a), which translated to the removal rate of 98 \(\pm\) 0.3% (Table 4, Figure 3b). Significantly higher TOCs were observed for S2 SER1--0.22 \(\pm\) 0.13 g/dm\({}^{3}\)--whereas S1 SER1 produced 0.10 \(\pm\) 0.07 g/dm\({}^{3}\) (Table 4, Figure 3a). An increase in OLR to 2.0 gCOD/dm\({}^{3}\)\(\cdot\)d led to a corresponding spike in the effluent TOC. In this case, the MW-heated series (S2) produced the lowest values: 0.25 \(\pm\) 0.15 g/dm\({}^{3}\) in SER1 (35 \({}^{\circ}\)C) and 1.70 \(\pm\) 0.04 g/dm\({}^{3}\) in SER2 (55 \({}^{\circ}\)C) (Table 4, Figure 3a). The V2 reactors thus managed to remove over 91% TOC (Table 4, Figure 3b). On the other hand, there were no statistically significant differences in TOC between the two stages of V3 (3.0 gCOD/dm\({}^{3}\)\(\cdot\)d). The H-LPSW treatment performance was also similar across all series. The TOC in S1 SER1 (35 \({}^{\circ}\)C) reached 0.50 \(\pm\) 0.19 g/dm\({}^{3}\) (82.9 \(\pm\) 4.1%) versus 0.45 \(\pm\) 0.18 g/dm\({}^{3}\) (84.6 \(\pm\) 3.5%) in S2 SER1 (Table 4, Figure 3a,b). Significantly better results  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**S/V**} & \multicolumn{3}{c}{**Chemical Oxygen Demand (COD)**} & \multicolumn{3}{c}{**Total Organic Carbon (TOC)**} \\ \cline{2-7}  & \multirow{2}{*}{**Parameter**} & \multicolumn{3}{c}{**Series**} & \multirow{2}{*}{**S/V**} & \multirow{2}{*}{**Parameter**} & \multicolumn{3}{c}{**Series**} \\ \cline{3-3} \cline{5-7}  & & **SER1—35 \({}^{\circ}\)C** & & & & **SER2—55 \({}^{\circ}\)C** \\ \hline \multirow{2}{*}{C1} & g/dm\({}^{3}\) & 0.68 \(\pm\) 0.08 & 0.37 \(\pm\) 0.05 & \multirow{2}{*}{C1} & g/dm\({}^{3}\) & 0.1 \(\pm\) 0.07 & 0.06 \(\pm\) 0.01 \\ \cline{2-7}  & \% rem. & 95.7 \(\pm\) 0.5 & 97.7 \(\pm\) 0.3 & & \% rem. & 92.2 \(\pm\) 1.2 & 98.2 \(\pm\) 0.4 \\ \hline \multirow{2}{*}{MW1} & g/dm\({}^{3}\) & 0.38 \(\pm\) 0.1 & 0.30 \(\pm\) 0.07 & \multirow{2}{*}{MW1} & g/dm\({}^{3}\) & 0.22 \(\pm\) 0.13 & 0.05 \(\pm\) 0.02 \\ \cline{2-7}  & \% rem.