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Ethylenediaminetetraacetic acid (EDTA) was decomposed by supercritical water oxidation (SCWO) in a tubular plug-flow reactor. The effect of the oxidant amount on the decomposition rate and efficiency was more significant at lower temperature. Also, excess oxidant played a key role in decreasing the activation energy for EDTA decomposition as CODCr. The nitrogen from EDTA was found to transform into NO3 -−N by thermal decomposition, while a portion of the nitrogen of EDTA and NO3 -−N was transformed into NH4 +−N and finally converted to N2 gas in the SCWO process. The decomposition kinetics of EDTA as CODCr in the SCWO process was described by a global rate expression.

A surface chemical analysis on the corrosion of various alloys under supercritical water oxidation (SCWO) conditions with relatively high concentrations of halogenated compounds and hydrogen peroxide was conducted using an Auger electron spectroscopy/scanning Auger-electron spectroscopy. The tested alloys (Inconel 600, Hastelloy C-276, Monel 400, stainless steel (SUS 316), Titanium G2, and Zirconium 702) were exposed to the same conditions:  4000 mg/L of 2,4-DCP at 400 °C and 250 bar, with 700% stoichiometric H2O2 in a Hastelloy C-276 batch reactor. Even under the supercritical water (SCW) condition of 4.8 pH without H2O2, a certain degree of corrosion was observed on the surface of all the alloys, especially SUS 316. Under the severe SCWO condition with excess H2O2, the surface corrosion of all the alloys was significant, but the types of corrosion on the alloy surfaces differed. Chromium in the SCWO process that contained H2O2 for halogenated compounds could potentially lead to the corrosion type and degree of alloys, but a certain amount of nickel depletion was also observed. Among the alloys tested, Titanium G2 was the most resistant to corrosion, under the conditions of the experiment. Considering that the surfaces of the alloys were covered by a carbon-contaminated layer, it may be concluded that the metal oxides or metal ions on the surface of the alloy have a role in forming the carbon-contaminated layer in the decomposition of halogenated compounds under SCWO.