Provided are a method of treating spent caustic occurring in a refinery process, a petrochemical process, and an environmental facility, and an apparatus thereof, wherein the spent caustic may be economically treated by a Fenton-like oxidation reaction at room temperature and atmospheric pressure in a reactor in which catalyst structures are stacked as compared to conventional methods of treating spent caustic.

A method of degrading 1,4-dioxane in the wastewater produced during the manufacture of alkyl ether sulfates is disclosed. The method includes the steps of (a) mixing from 100 to 10,000 ppm, preferably 1,000 to 4,000 ppm of ozone with the wastewater; (b) introducing H.sub.2O.sub.2 into the wastewater in an amount of 0.01 to 10, preferably 0.1 to 0.5 molar equivalents of H.sub.2O.sub.2 to ozone, and (c) mixing the ozone, H.sub.2O.sub.2, and wastewater to generate hydroxyl radicals reactive with the 1,4-dioxane, without the addition of a metal catalyst. The hydroxyl radicals react with the 1,4-dioxane and degrade it into carbon dioxide, water and/or carbonate. The method is effective to reduce a concentration of 1,4-dioxane in the wastewater from a range of about 10 ppm to about 1000 ppm of dioxane down to less than 5 ppb of 1,4-dioxane after treatment. The method is also effective for removing hydrocarbon species that may be present in the wastewater.

Methods, systems, and techniques for removal of PFAS contaminants from contaminated soil or sediment are provided. Example embodiments provide a water-based ex-situ method and system at a site that utilizes particle size and particle density segregation; deagglomeration, attrition, and retention time and sequential contacts with purified water; a recirculating water system with continual water treatment, and additional modules for destructive treatment of concentrated PFAS. In an example embodiment, the water treatment system of an example PFAS contaminant removal system and process includes ion exchange resin filtration component to remove PFAS effectively.

A method of purifying a produced water comprising contacting a produced water stream with a composition comprising a (i) a chelant; (ii) an oxidizing agent; and (iii) a surfactant under conditions suitable for the formation of a purified produced water. A composition for purifying produced water comprising (i) a biochelant in an amount of from about 1 wt. % to about 10 wt. %: (ii) an oxidizing agent in an amount of from about 3 wt. % to about 50 wt. %; (iii) a surfactant in an amount of from about 0.1 wt. % to about 70 wt. % wherein the weight percentage is based on the total weight of the composition; and (iv) a solvent.

A photodynamic composite including a porphyrin having four quaternized nitrogens, wherein the porphyrin is covalently bonded to a polymer containing reactive amines covalently bonded to a solid-state support is claimed. A method for sanitizing contaminated water is claimed including exposing the contaminated water to the photodynamic composite, in the presence of light and oxygen, wherein, a sufficient quantity of singlet oxygen and super oxide anions is provided by the chemical reaction of the light and the photosensitizer to destroy the pollutants or pathogens present in the contaminated water and to oxidize organic contaminants into carbon dioxide and water; thereby rendering the water potable.

An alkaline aqueous ferric iron salt solution is disclosed. Generally, the alkaline aqueous ferric iron salt solution comprises ferric ions (Fe.sup.3+), potassium ions (K.sup.+), carbonate ions (CO.sub.3.sup.2−), bicarbonate ions (HCO.sub.3.sup.−), hydroxide ions (OH.sup.−), optionally nitrate ions (NO.sub.3.sup.−). Further, a molar ratio of the potassium ions to the ferric ions is generally at least 5.0. The ferric iron is complexed with carbonate, bicarbonate or both to form a water-soluble complex that is anionic in nature and highly soluble in the alkaline aqueous ferric iron salt solution at pH above 8.5, and a pH of the alkaline aqueous ferric iron salt solution is at least 8.5.

An alkaline aqueous ferric iron salt solution is disclosed. Generally, the alkaline aqueous ferric iron salt solution comprises ferric ions (Fe.sup.3+), potassium ions (K.sup.+), carbonate ions (CO.sub.3.sup.2−), bicarbonate ions (HCO.sub.3.sup.−), hydroxide ions (OH.sup.−), optionally nitrate ions (NO.sub.3.sup.−). Further, a molar ratio of the potassium ions to the ferric ions is generally at least 5.0. The ferric iron is complexed with carbonate, bicarbonate or both to form a water-soluble complex that is anionic in nature and highly soluble in the alkaline aqueous ferric iron salt solution at pH above 8.5, and a pH of the alkaline aqueous ferric iron salt solution is at least 8.5.

A method for removing silica from an aqueous solution is provided. The method includes steps of flowing the aqueous solution into an electro-Fenton reactor, wherein the reactor comprises one or more electrodes in a bipolar arrangement positioned between a monopolar iron anode and a monopolar cathode; applying an electric current to the aqueous solution such that silica aggregates form on ferric hydroxide; and removing the silica aggregates from the aqueous solution.

The invention relates to the methods for sewage treatment contaminated by mechanical impurities, fats, proteins and other organic and inorganic compounds, and can be used for purification and water disinfection contaminated by heavy and radioactive metals, saturated or unsaturated fats, filtrate from landfills, meat processing plants, and/or oil and petroleum. The method includes flotation, electrocoagulation and filtration, and provides: mixing water with carbon-based sorbent; filtration of water and carbon sorbent on rubber-based hydrophobic sorbent; decomposition of organic substances accumulated on carbon and rubber sorbents; floatation with hydrogen peroxide; recovery active substance in hydrogen peroxide; reuse thereof; electrocoagulation with water saturation with oxygen and hydrogen, formed on indispensable carbon or metal electrodes based on the of aluminum, titanium, sodium, tin, copper, and other metals; water disinfection by electro-cavitation; generation of active substance based on the iron and titanium atoms; water filtration on the precoat filter; and filtering on activated carbon filter.

A method of removing chemical contaminants from a composition comprising an active, a solvent, and a contaminant can include providing an initial feed supply, wherein the initial feed supply comprises the active, the solvent, and the contaminant, wherein the contaminant can include 1,4 dioxane, dimethyl dioxane, or a combination thereof; including filtering the initial feed stock through a nanofilter and using reverse osmosis.