Process for treating waste via hydrothermal treatment

摘要

Hydrothermal oxidation of organic compounds, optionally with oxidizable inorganic compounds, is contained in an aqueous effluent. The aqueous effluent is injected within a tubular reactor and brought to supercritical pressure, and temperature is increased to a supercritical temperature, without any intermediate decrease in temperature, by introducing sufficient amounts of oxidizing agent within the tubular for totally oxidizing the organic compounds, and optionally for partly oxidizing oxidizable inorganic compounds. The oxidizing agent is introduced in a fractionated way in several points increasingly located downstream, and the composition and/or the concentration of the organic compounds and/or oxidizable organic compounds within the effluent to be treated varies over time. Further, upstream from the tubular reactor where oxidation is carried out, the effluent's total chemical oxygen demand of the effluent to be treated is measured and monitored at more than 120 grams/liter (g/L) and less than 250 g/L prior to injecting the tubular reactor.

主权项

1. A process for hydrothermal oxidation of organic compounds contained in an aqueous effluent, optionally with oxidizable inorganic compounds, wherein said aqueous effluent is injected within a tubular reactor wherein the effluent is brought to a supercritical pressure and wherein the temperature of the effluent is gradually increased from its initial temperature up to a supercritical temperature, designated by Tfinal, without any intermediate decrease in temperature during the increasing time-dependent change up to Tfinal, by introducing within said tubular reactor a sufficient amount of oxidizing agent for totally oxidizing the organic compounds and optionally for at least partly oxidizing oxidizable inorganic compounds, the oxidizing agent being introduced in a fractionated way into several points increasingly located downstream from the reactor,
characterized in that the composition and/or the concentration of the organic compounds and/or oxidizable inorganic compounds within the effluent to be treated varies over time, and in that, upstream from the tubular reactor wherein oxidation is carried out, the TOD of the effluent to be treated is measured and maintained or adjusted if required, to a value of more than 120 g/L and of less than 250 g/L prior to its injection into the tubular reactor.