## 3 Results
### Oxygen Uptake Rate Tests  
#### 3.2.1 Batch Tests  
As can be seen in Figure 2, the kinetics of the oxygen consumption increased by lowering the pH from about 9-10 to about 8. Furthermore, because industrial biomass B1 was already acclimated to \"unconventional\" pollutants, it had higher biological kinetics than the municipal biomass B2 when put in contact with the substrate containing AOXs, even if the endogenous value was lower for biomass B1. Figure 2: Effect of pH value. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Parameter** & **Lab-1** & **Lab-2** & **Lab-3** & **Lab-4** \\ \hline \multirow{4}{*}{**Adsorption procedure:** **frits (batch), column**} & Frits (shaking procedure paragraphs 9.3.2 of the ISO 9562 method) & 100 mL of sample (diluted based on expected concentration) + 5 mL of nitrate solution (NaNO\({}_{3}\) + HNO\({}_{3}\)), agitated with a rocking agitator for 1 h & & Column method (paragraphs 7.1.3 and from ISO 9562 method & 9.3.4 of the ISO 9562 method) \\ \hline \multirow{4}{*}{**Adsorption procedure:** **frits (batch), column**} & Frits (shaking procedure paragraphs 9.3.2 of the ISO 9562 method) & 50 mg of activated carbon & Analytik Jena vials containing \(\sim\)50 mg each; 2 vials used per sample & Specific cartridges provided by supplier; quantity was approx. 50–200 mg \\ \hline \multirow{4}{*}{**Volume of sample** **used for adsorption or contact with the fruit**} & 100 mL & 100 mL (diluted as needed) & 100 mL of sample used as or diluted & 100 mL per method \\ \hline \multirow{4}{*}{**Volume of ultrapure** **waster used for washing before** **combustion**} & 5–10 mL of diluted & Washed with sodium nitrate solution used for washing, additional 5 mL for rinsing & 25 mL of washing solution as per supplier method & 25 mL of washing solution, prepared by diluting stock solution \\ \hline \multirow{4}{*}{**Any other data for AOX quantification**} & Blank counts: \(\sim\)0.2 ug; dilution factor: 100; formula: (sample counts—blank counts) & Calibration curve: 10–250 ppb; control charts for blanks; adsorption capacity checks; 0.01 M HCl titration check & & Initial 100 mL sample volume; dilution factor considered; results in \(\mu\)g/L \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Additional information requested from different analytical laboratories. Figure 3 compares the biological kinetics of the different biomasses from municipal WWTPs with different capacities. It can be observed that, as the biological kinetics increased with plant capacity, the biomasses originating from medium-to-low WWTPs required acclimatization. Comparing the kinetics of oxygen consumption in the tests of the different samples containing different AOX concentrations, it can be noticed that there was no a considerable change in short-term oxygen consumption with a DF of 1:5 (Figure 4). With regard to DF 1:1, there was an increase in oxygen consumption shifting from the sample with the higher AOX concentration (i.e., for 148.00 mg\({}_{\text{AOX}}\) L\({}^{-1}\), the sOUR was 13.884 mg\({}_{\text{DO}}\) g\({}_{\text{vSS}}\)\({}^{-1}\) h\({}^{-1}\)) to the sample with the lower AOX concentration (i.e., for 2.00 mg\({}_{\text{AOX}}\) L\({}^{-1}\), the sOUR was 20.891 mg\({}_{\text{DO}}\) g\({}_{\text{vSS}}\)\({}^{-1}\) h\({}^{-1}\)). Thus, for a sample with a given AOX content, it may be concluded that the sample's oxygen consumption will increase with the dilution factor. Figure 4: Effect of AOX concentration on biomass B1. Figure 3: Effect of biomasses coming from municipal WWTPs with different capacities. Figure 5 shows that the different types of AOXs--i.e., conventional (natural) AOX and bad (anthropogenic) AOX--had similar short-term oxygen consumption kinetics for both types of biomasses tested (B1 and B2). However, with a higher DF, i.e., a lower concentration of the AOX, the kinetics of the oxygen consumption was higher.