A process performed by a plant for oxidation of a waste stream with oxidizable material is described. In a start-up phase, supercritical water is fed to a supercritical water oxidation reactor, heating the process up to supercritical conditions. In a treatment phase, the waste stream is fed to the reactor for supercritical water oxidation treatment, in which sufficient mass of water under supercritical conditions is present in the reactor to retain supercritical conditions with the newly introduced waste stream. Oxygen is used as oxidant and a stoichiometric quantum is added to the reactor. The energy released from the oxidation reaction substitutes the energy provided by the addition of supercritical water up to a point where the reactor achieves near autothermal conditions with supercritical water providing trim heat requirement. The reactor outlet is quench cooled, neutralised and energy is recovered from it. A gas liquid separator ensures that the effluent stream is degassed.

Supercritical water oxidation (SCWO) is a destruction technology to quickly treat per- and polyfluoroalkyl substance (PFAS)-impacted groundwater, investigation derived waste, and other aqueous matrices such as landfill leachate and aqueous film forming foam. Laboratory-prepared and field-collected samples with inlet PFAS concentrations up to 50 parts per million were consistently destroyed to less than 70 parts per trillion for all PFAS, when running at the determined optimal operating conditions (≥600° C. and 3,500 pounds per square inch). We investigated the correlation between temperature and flowrate of the system, finding that reactor temperatures ≥450° C. destroys perfluorinated carbonic acids, but higher temperatures and specified conditions are necessary to destroy perfluorosulfonic acids. Using a higher density oxygen source also increases the throughput of a SCWO reactor, here up to 140 mL/min, without affecting PFAS destruction. Continuous 5-log reduction in the concentration of PFAS (99.999% destruction) is demonstrated for 3 hours at steady-state operation. The destruction efficiency is not impacted by the addition of co-contaminants such as petroleum and other organic hydrocarbons, and the SCWO process is successfully applied to waste streams without pretreatment. The treated effluent is largely comprised of complete combustion products including carbon dioxide, water, and the corresponding anion acids; hence, the treated liquid can be released back into the environment after neutralization.

The invention relates to a method of producing a binder comprising the steps of preparing (20) a residual material comprising amorphous alumina-rich and/or aluminium hydroxide-rich constituents, heating (30) the residual material to produce a fired material, the heating (30) of the residual material being at a temperature of >800° C.

A waste processing system includes a reactor including an inlet end and an outlet end configured to discharge reactor effluent. The inlet end includes a mixing unit having an oxidizing material input and a waste stream input. The reactor oxidizing material input is configured to receive reactor oxidizing material at a temperature greater than 200° C. and at a pressure greater than 60 atm. A second waste stream input is positioned between the reactor inlet end and the reactor outlet end.

The disclosure discloses a system for treating high-salt high-organic wastewater and recovering energy, the system includes a cold wall-type reactor (6), a multi-level cyclone separator (16, 19, and 25), a waste liquid feeding system, an oxidant feeding system and a fuel feeding system; The cold wall-type reactor designed by the disclosure is formed by inner and outer double-housing structures, a cooling medium is fed into a gap between the inner housing and the outer housing of the reactor, the fluid on an inner wall surface of the inner housing of the reactor is cooled below a supercritical temperature of the water by using countercurrent heat exchange, blockage of the inorganic salts is effectively prevented. The disclosure is capable of realizing gradient utilization of the reaction heat of the high-salt high-organic wastewater supercritical water oxidation system, and improving a system energy recovery utilization ratio in the greatest degree.

The invention relates to the use of a hydraulic binder containing calcium aluminate, obtainable by a method in which a) prepared amorphous residual material rich in aluminium oxide and/or aluminium hydroxide is heated after the addition of a b) calcium ion-containing binder component and c) water, for the production of a constructing material.

A method for processing water treatment residuals, or other amorphous aluminium oxide or aluminium hydroxide rich waste residuals, for use in the manufacture of hydraulic binders, comprising heating the residuals to remove water and oxidise organic material contained therein, comprising controlling the temperature of the residuals during heating such that they are heated to a temperature no higher than 800° C., more preferably no higher than 650° C., to ensure that aluminium compounds in the WTR, in particular aluminium oxide and aluminium hydroxide, remain in an amorphous state. The method may comprise controlling the temperature of the water treatment residuals such that they are heated to a temperature between 350° C. and 650° C., more preferably between 400° C. and 500° C.

A method for processing water treatment residuals, or other amorphous aluminium oxide or aluminium hydroxide rich waste residuals, for use in the manufacture of hydraulic binders, comprising heating the residuals to remove water and oxidise organic material contained therein, comprising controlling the temperature of the residuals during heating such that they are heated to a temperature no higher than 800° C., more preferably no higher than 650° C., to ensure that aluminium compounds in the WTR, in particular aluminium oxide and aluminium hydroxide, remain in an amorphous state. The method may comprise controlling the temperature of the water treatment residuals such that they are heated to a temperature between 350° C. and 650° C., more preferably between 400° C. and 500° C.

Provided herein are methods, systems, and apparatuses for energy-efficient supercritical water oxidation of waste. The supercritical water oxidation processes and systems described herein may incorporate one or more of the following features: compression of large amounts of oxidant for plant-scale operations in an energy-efficient manner; the use of air as an oxidant; using reactor effluent to drive a turbine or other gas expander for energy recovery; and recovery of pressure and heat of reactor effluent. In some embodiments, the systems and methods are energy-neutral or energy-positive.

Aqueous effluent treatment system including a separation reactor having a reactor chamber fluidly connected to an aqueous effluent source, connected via a pump to an inlet of the reactor chamber, a fluid extraction system connected to a liquid effluent outlet at a top of the reactor chamber, and a solid residue extraction system connected to a solid residue outlet at a bottom of the reactor chamber. The separation reactor is operable to generate pressures exceeding 22 MPa and temperatures exceeding 300° C. in the reactor chamber configured to generate a supercritical zone in an upper portion of the reactor chamber to which the liquid effluent outlet is connected, and a subcritical zone in a lower portion of the chamber within the reactor chamber to which the solid residue outlet is connected. The solid residue extraction system comprises an output circuit comprising a collector coupled to the solid residue outlet via a collector input valve (V1) and to a water output tank via a filter and a collector liquid output valve (V4) operable to be opened to cause a pressure drop at the solid residue outlet to draw solid residue out of the reactor chamber, the solid residue extraction system further comprising a gas feed circuit connected via a gas supply valve (V5) to the collector, the gas supply valve operable to be opened to extract solid residues in the collector to a solids output tank connected to the collector via a collector solids output valve (V6).