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.

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.

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).

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.

Described herein is a reactor (1) includes: a first reaction volume (V1), a second reaction volume (V2), wherein: the first reaction volume (V1) is in fluid communication with an inlet port for an oxidizer agent (OX_IN), an inlet port for at least one first reactant (R1_IN) and an outlet port for at least one reaction product (P1_OUT), said second reaction volume (V2) is in fluid communication with an inlet port for at least one second reactant (R2_IN), an outlet port for at least one second reaction product (P2_OUT) and is furthermore in thermal exchange relationship with said first reaction volume (V1), wherein, during operation, in said first reaction volume (V1) an oxidation reaction occurs between said at least one first reactant and said oxidizer agent with the formation of said at least one first reaction product, and in said second reaction volume (V2) a gasification reaction occurs of said second reactant with the contribution of a thermal energy flow exchanged between the first and the second reaction volumes (V1, V2) with formation of said at least one second reaction product.

A horizontal self-balancing supercritical reaction apparatus, comprising a pressure vessel, a high pressure air compression apparatus, and at least one reactor arranged within the pressure vessel. The reactor is internally provided with front and rear pistons, two ends of the reactor are sealed by the reactor front piston and the reactor rear piston, a pressure medium is filled between the reactor front piston and an inner wall of the pressure vessel, the reactor rear piston is connected to a rear piston driving motor by a rear piston push rod, the reactor is provided with a water inlet and a water/air outlet which are controlled by valves, the reactor is internally provided with a heating apparatus, and the high pressure air compression apparatus is connected to the inside of the reactor. The present invention utilises a pressure self-balancing system, which significantly improves the stress characteristics of the reactor.

A process including introducing, into a device, an aqueous fluid containing at least one inorganic salt, the water of the aqueous fluid being in supercritical conditions or close to the supercritical range in the device, and measuring the concentration or the amount of inorganic salt in the device, this measurement preferably being carried out before the entry of the inorganic salt into the device, Then bringing the inorganic salt into contact with an aqueous flow containing at least one hydroxide salt to obtain in the device an aqueous fluid mixture containing an inorganic salt and a hydroxide salt and adjusting the concentration or amount of the hydroxide salt as a function of the concentration or amount of the inorganic salt needed to at least partially solubilize the inorganic salt. Preferably the measurement of the concentration or the amount of inorganic salt leaving the device is also performed.

Disclosed herein are embodiments of a hydrothermal reactor, such as a downflow hydrothermal reactor and methods of using the same. Also disclosed herein are system embodiments comprising the hydrothermal reactor. Method embodiments disclosed herein facilitate determining operation parameters for the hydrothermal reactor that give rise to efficient feedstock conversion to products while maintaining integrity of the reactor (e.g., avoiding corrosion) and providing safe operating conditions. The disclosed reactor and system embodiments facilitate situations where small scale and/or remote destruction of feedstocks (e.g., chemical warfare agents and/or environmental toxins) is needed.