Abstract: Per- and polyfluoroalkyl substances (PFAS) are destroyed by oxidation in supercritical conditions. PFAS in water is concentrated in a reverse osmosis step and salt from the resulting solution is removed in supercritical conditions prior to destruction of PFAS in supercritical conditions.

Abstract: Disclosed is a method for phosphorus absorption by hydration and fluorine recovery for a fume exiting a kiln in a kiln process for the production of phosphoric acid, comprising the following steps: a fume containing P2O5 and fluorine exiting a kiln is introduced into a hydration tower, the fume performs heat and mass transfer with the spraying liquid, with most of the phosphoric acid produced being absorbed into the spraying liquid; the phosphoric acid solution falling from the spraying finally enters the acid solution circulating and spraying system; the fume discharged from a fume outlet then passes through a phosphoric acid mist capturing tower and a mist removing and separating tower successively, such that the phosphoric acid mist entrained in the fume exiting the hydration tower is further captured.

Abstract: The present invention is a purification system for removing hydrogen fluoride and water from an electrolytic solution for lithium-ion secondary batteries in which [1] a purifier for removing hydrogen fluoride containing a hydrogen fluoride adsorbent selected from among carbonate hydrotalcites and calcined hydrotalcites and [2] a purifier for removing water containing an adsorbent for trapping water are connected in this order from upstream to downstream.

Abstract: Wastewater treatment systems, methods and apparatus for polishing a wastewater stream comprising a plurality of contaminants are provided. One system includes a vessel containing a plurality of natural media filtration agents selected to remove selected ones of the plurality of contaminants from the wastewater stream. In one embodiment, the vessel includes a bed of bauxite residue and at least one other natural media filtration agent. In another embodiment, the vessel includes a bed of compost and at least one other natural media filtration agent. The vessel includes a wastewater inlet that is in fluid communication with one or more of the natural media filtration agents. The vessel includes a wastewater outlet that is in fluid communication with one or more of the natural media filtration agents.

Abstract: In order to remove fluorine from a zinc containing solution before zinc electro-refining in lower cost, fluorine is removed by adsorption from a zinc containing solution (leached solution) utilizing the character of the predetermined iron compound or zinc compound which can adsorb fluorine in an acid solution and desorb fluorine in an alkaline solution. The fluorine adsorbent/desorbent having adsorbed fluorine is treated in an alkaline solution, to desorb the fluorine. This makes it possible to regenerate the fluorine adsorbent/desorbent. Further, an electrolytic solution for zinc electro-refining can be prepared in lower cost, thus total zinc refining costs can be reduced.

Abstract: In order to remove fluorine from a zinc containing solution before zinc electro-refining in lower cost, fluorine is removed by adsorption from a zinc containing solution (leached solution) utilizing the character of the predetermined iron compound or zinc compound which can adsorb fluorine in an acid solution and desorb fluorine in an alkaline solution. The fluorine adsorbent/desorbent having adsorbed fluorine is treated in an alkaline solution, to desorb the fluorine. This makes it possible to regenerate the fluorine adsorbent/desorbent. Further, an electrolytic solution for zinc electro-refining can be prepared in lower cost, thus total zinc refining costs can be reduced.

Abstract: To provide a good and simple method for decomposing and detoxifying a hardly decomposable fluorinated organic compound. Specifically, a fluorinated organic compound is decomposed by bringing an aqueous solution of the fluorinated organic compound into contact with a catalyst containing a metal oxide. The metal oxide may preferably be an oxide of at least one metal selected from the group consisting of Ni, Pd, Cu, Mn, Fe and Co, and more preferably be nickel oxide. The contact temperature is preferably within the range of from 0 to 100° C. Preferably, the fluorinated organic compound to be decomposed is an organic fluorocarboxylic acid, an organic fluorosulfonic acid or a salt thereof, which is used as a surfactant or an surface treatment agent.

Abstract: A method for the treatment of waste water from florfenicol production is provided, which mainly comprises the steps as follows: adding iron chips or steel slag to waste water from a copper salt workshop, regulating the pH value, filtering, then adding limestone, lime or Ca(OH)2 and having a solid-liquid separation; blending the treated waste water and waste water from a splitting workshop, oxidizing the residual reductive matter by ozone and removing NH3-N by blowing; blending the treated water and waste water from esterifying or florfenicol workshops and diluting the blended water, adding phosphate and microelement, regulating the pH value, then having an anaerobic treatment in an anaerobic reactor; diluting the treated waste water, then having an aerobic treatment in an aerobic reactor.

Abstract: A process for the treatment of phosphoric acid plant pond water facilitating the recovery of phosphorus values from the input pond water. In certain aspects the process recycles solids from a later stage neutralization and separation into the clarified liquid stream from an initial clarification and neutralization stage. A sufficient amount of solids are added to the clarified liquid stream to effect the pH-dependent precipitation of a phosphate product. In alternative aspects an intermediate pH-dependent precipitation of a phosphate product is achieved through the addition of a neutralizing agent. The phosphate product is further characterized by a low concentration of fluoride. In addition the phosphate product can be further processed to a high purity technical grade phosphoric acid. In certain aspects the process employs flocculating agents to enhance the formation of precipitates. In further aspects, methodologies taught herein facilitate the reduction of silica in the process streams.

Abstract: A process for the treatment of industrial waste water. The process includes the steps of admixing partially-treated waste water containing precipitated impurities with a flocculating agent in a flocculation basin, directing the admixed waste water to an elongated sedimentation basin, allowing flocculated solids in the waste water to settle to the bottom of the sedimentation basin, removing the settled solids from the bottom of the sedimentation basin and directing the treated water from the sedimentation basin. The process can further include the step of adjusting the pH of the waste water to precipitate impurities in the waste water prior to the addition of the flocculation agent. The elongated sedimentation basin can include a pair of sloped sides to consolidate the settled solids at the bottom of the basin. The settled solids can then be removed by suction. The basins can be formed from the excavation or impoundment of earth in an area adjacent to a waste water-generating facility.

Abstract: A wastewater treatment equipment of an embodiment of the present invention neutralizes a WTBT 12 by introducing the WTBT 12 containing fluorine components to a first treatment tank 11A and by introducing an NaOH solution from a second path P2 and so on. The fluorine components contained in the WTBT 12 is then fixed as calcium fluoride by adding calcium components to the WTBT 12 stored in a second treatment tank 11B. Furthermore, MTBR like calcium fluoride are separated from the WTBT in a third treatment tank 11C. The separated MTBR are rinsed and dewatered in a filter press 17.

Abstract: A method for removing fluorine from wastewater includes the steps of: adding a fluorine-reactive agent, that comprises a water-soluble sodium compound and a water-soluble aluminum compound, into the wastewater so as to form sodium ions and aluminum ions in the wastewater and so as to precipitate sodium aluminum fluoride by reaction of the sodium ions and the aluminum ions with fluorine ions in the wastewater; and removing the precipitate of sodium aluminum fluoride from the wastewater.

Abstract: A process to substantially remove the fluorinated anionic surfactants from fluoropolymer dispersions comprising the following steps: a) addition to the fluoropolymer dispersion of an anionic polyelectrolyte; b) contact of the dispersion with an anionic exchanger; c) separation of the dispersion from the anionic exchanger and recovery of the dispersion substantially fluorinated anionic surfactant free.

Abstract: First, a primary fluoric ion concentration detection process is performed, and a primary calcium salt addition process is performed to add calcium salt in a first reaction tank, wherein the dosage of the calcium salt in the primary calcium salt addition process is determined according to the detected fluoric ion concentration. Thereupon, a secondary calcium salt addition process is performed to add calcium salt into the second reaction tank. Following that, a solid-liquid separation process is performed to separate calcium fluoride from the wastewater, and a secondary fluoric ion concentration detection process is performed upon the wastewater after the calcium fluoride is separated. Finally, the dosage of the calcium salt in the secondary calcium salt addition process is determined in a feed back control manner according to the detected fluoric ion concentration.

Abstract: An improved water decontamination process comprising contacting water containing anionic contaminants with an enhanced coagulant to form an enhanced floc, which more efficiently binds anionic species (e.g., arsenate, arsenite, chromate, fluoride, selenate, and borate, and combinations thereof) predominantly through the formation of surface complexes. The enhanced coagulant comprises a trivalent metal cation coagulant (e.g., ferric chloride or aluminum sulfate) mixed with a divalent metal cation modifier (e.g., copper sulfate or zinc sulfate).

Abstract: Significant amounts of soluble fluoride, known to create problems in processes requiring high quality grade calcium chloride, are removed from calcium chloride solution using hydroxyapatite as a removal mechanism. Under acidic conditions, calcium chloride solution is purified to about less than 10 ppm fluoride, significantly, to less than 1 ppm fluoride. At least 0.1 weight percent hydroxyapatite and concentrated hydrochloric acid are added to calcium chloride solution and slurried to remove fluoride and create a highly purified calcium chloride solution, substantially free of fluoride.

Abstract: The present invention provides a method of removing a fluorinated surfactant from waste water comprising fluoropolymer particles. The method comprises (i) adding a non-fluorinated surfactant to the waste water (ii) contacting the thus obtained waste water with adsorbent particles to adsorb at least a portion of the fluorinated surfactant to the adsorbent particles and (iii) separating the waste water and the adsorbent particles.

Abstract: A method for removing calcium from water containing a high concentration of calcium bicarbonate, permitting a reduction of the calcium bicarbonate equivalent to 200-500 ppm calcium to the level in accordance with the water quality standards for industrial use, not by a method using a large amount of heat and power as heating and deairing, but by a simple chemical treatment. Calcium hydroxide is added to waste water containing a high concentration of calcium in a form of calcium bicarbonate for making them react with each other, and removing calcium by fixing it to calcium bicarbonate.

Abstract: Trace impurities such as organic compounds in an inert, non-reactive or reactive liquid such as ammonia, hydrogen chloride, hydrogen bromide, and chlorine are reduced by at least a factor of 5 using liquid purifying systems that contain an ultra-low emission (ULE) carbon. The moisture level of the purified reactive liquid is only slightly higher than that of the contaminated liquid.

Abstract: A process for the partial purification of contaminated phosphoric acid plant pond water is described, in which the pond water is treated sequentially, with two basic compounds, clarified, aged, clarified again and re-acidified. The thus treated pond water, still containing the majority of the phosphate originally present, can then be concentrated via the removal of essentially pure water, using any conventional means of concentration, without the formation of solid precipitates.

Abstract: An improved method of treating wastewater to remove ammonia and fluoride is provided. The method comprises the steps of chemical destruction of ammonia with an oxidizing agent, followed by treatment with calcium salts to precipitate insoluble calcium fluoride, and filtration to remove the precipitate.

Abstract: A system for removing fluoride from wastewater is provided. The system comprises a reaction tank for processing said wastewater by adding calcium salts, a filtration tank for removing the precipitated fluoride formed in the reaction tank, a single fluoride electrode disposed at the reaction tank for measuring a concentration of fluoride in the influent wastewater and providing an output signal, and a programmable controller for controlling addition of said calcium salts into said reaction tank. The programmable controller defines a setpoint of fluoride concentration in the reaction tank and automatically controls addition of calcium salts based on the setpoint and the output signal provided by the single fluoride electrode. A method of removing fluoride from wastewater is also provided.

Abstract: A method of removing arsenic and fluoride from aqueous solutions in the same process is provided. Specifically, the pH of the aqueous solution is adjusted to a pH in the range of about 5 to 8. A combination of calcium salts, and ferric or aluminum salts are added to form insoluble arsenic and fluoride bearing solids. The solids are then removed from the aqueous solution.

Abstract: The present invention provides a process for eliminating halogen-containing compounds contained in a gas or a liquid, characterized in that the gas or liquid is brought into contact with a composition based on an alumina and/or a hydrated alumina and at least one compound (A) comprising at least one metallic element selected from metals from groups VIII, IB and/or IIB of the periodic table, and in that the total metallic element(s) content is at most 45% by weight with respect to the total composition weight, the complement by weight preferably comprising in a major part alumina and/or hydrated alumina.

Abstract: An apparatus for treatment of fluorine waste water has an introduction tank, a main treatment tank, a calcium hydroxide tank, a polychlorinated aluminum tank, a macromolecular flocculant tank, a settling tank, and a concentration tank. Fluorine waste water is introduced through the introduction tank into a lower part of the main treatment tank through a lower inlet pipe. Also, return sludge from the concentration tank and silicon sludge from a silicon waste water treatment system are introduced into an upper part of the main treatment tank. Thus, silicon recovered from silicon waste water is recycled for treatment of fluorine waste water. Also, unreacted chemicals, which have been loaded in the calcium hydroxide tank, polychlorinated aluminum tank, macromolecular flocculant tank, are recycled. The main treatment tank has no stirrer, and thus conserves electrical energy, but can neutralize the waste water.

Abstract: A process and apparatus for treating a fluorine-containing waste solution that is able to maintain a high treatment volume while also facilitating easy maintenance. A calcium salt such as calcium hydroxide and an inorganic coagulant are added with timing to the fluorine-containing waste solution, followed by filtration of said waste solution by cross-flow filtration.

Abstract: In the waste water treatment apparatus, organic matter-containing fluorine waste water is treated in a reaction tank into which biological sludge and calcium-containing chemical sludge are introduced, thus making it possible to treat organic matters in the waste water by microorganisms contained in the biological sludge, and simultaneously to treat fluorine in the waste water by the calcium-containing chemical sludge. Therefore, since organic matters in the waste water and fluorine in the waste water, which differ in chemical properties from each other, can be treated with one reaction tank, it is no longer necessary to provide two reaction tanks, thus allowing the initial cost to be reduced. That is, this waste water treatment apparatus is capable of reducing the quantity of waste materials and reducing both initial cost and running cost.

Abstract: The present invention relates to a remover of dissolved fluoride ion for removing fluoride ions contained in wastewater and a treatment method for wastewater containing fluoride using the same. In order to achieve the above objects, the present invention provides a remover of dissolved fluoride ion comprising: a) hydrochloric acid solution reacted with calcium carbonate, and b) a mixture of poly sodium metaphosphate and active aluminum or aqueous solution of mixtures thereof, or an aqueous solution of rare earth element compound, and a treatment method for wastewater containing fluoride using the same.

Abstract: The present invention relates to a method of defluoridation of waste water, including a step of acid neutralization between a basic neutralization step and a decantation step.

Abstract: The present invention concerns a process for eliminating, reducing and/or suppressing halogenated compounds, in particular chlorinated compounds, contained in a gas or a liquid, in which the gas or liquid is brought into contact with a composition obtained by depositing at least one compound comprising at least one element selected from alkalis on an alumina, followed by calcining the alumina at a temperature of at least 600° C. When at least one compound comprising at least one element selected from alkaline-earths and rare earths is deposited on the alumina, the alumina calcining temperature is at least 500° C.

Abstract: An apparatus for treatment of fluorine waste water has an introduction tank, a main treatment tank, a calcium hydroxide tank, a polychlorinated aluminum tank, a macromolecular flocculant tank, a settling tank, and a concentration tank. Fluorine waste water is introduced from the introduction tank into a lower part of the main treatment tank through a lower inlet pipe. Also, return sludge from the concentration tank and silicon sludge from a silicon waste water treatment system are introduced into an upper part of the main treatment tank. Thus, silicon recovered from silicon waste water is recycled for treatment of fluorine waste water. Also, unreacted chemicals, which have been loaded in the calcium hydroxide tank, polychlorinated aluminum tank, macromolecular flocculant tank, are recycled. The main treatment tank has no stirrer and thus conserves electrical energy, but can still neutralize the waste water.

Abstract: A media is used to remove species from aqueous solutions, particularly in the treatment of water to enable it to be suitable for drinking. The media includes a material selected from the group consisting of zirconium hydroxide, titanium hydroxide, hafnium hydroxide and combinations thereof. A preferred form of the media is a layer having an aspect ratio of at least 1:1, more preferably, at least about 10:1. Removed from the water are species selected from the group consisting of arsenate, selenate, chromate, borate, perchlorate, fluoride and combinations thereof. In particular arsenite (As+3) containing species are also removed from water. Arsenite may be removed from water to levels not greater than 10 parts per billion with a single exposure to the media. The media is selective for certain species over others.

Abstract: This invention provides a compact effluent water reclamation apparatus which is minimized in the kinds and amounts of chemicals to be used for the recovery of water to thereby reduce the amount of waste and eliminate equipment which necessitates a large area for installation. The effluent water reclamation apparatus comprises a reverse osmosis device and is adapted to treat acid-alkali effluent water containing organic matter but no fluorine, by concentrating the acid-alkali effluent water containing organic matter by reverse osmosis, evaporating the resulting concentrated water to dryness and collecting the water permeating through a reverse osmosis membrane.

Abstract: A waste water treatment equipment treats a fluorine waste water containing organic matter, nitrogen, phosphor and hydrogen peroxide by an anaerobic tank 3 in which a calcium carbonate mineral 9 is placed and an aerobic tank 15 in which the calcium carbonate mineral 9 is placed and into which a biologically treated water is introduced from a treatment equipment 444 of another system. Therefore, the fluorine in the waste water can be treated by the calcium carbonate mineral 9 placed in the anaerobic tank 3 and the aerobic tank 15 with the formation of calcium fluoride 11. The organic matter of the surface active agent and so on in the waste water can be treated by the microorganism included in the biologically treated water. Furthermore, nitrate nitrogen can be treated so as to be reduced to a nitrogen gas in the anaerobic tank 3, while ammoniacal nitrogen and nitrite nitrogen can be treated so as to be oxidized in the aerobic tank 15.

Abstract: In a waste water treatment apparatus, sludge settled in a settling tank is treated by being introduced (returned) into a return sludge reaction tank having a settling section in its rear portion. Therefore, unreacted chemicals contained in the sludge that has settled in the settling tank can be utilized in the return sludge reaction tank. Therefore, the unreacted chemicals are not discharged as sludge. Accordingly, as compared with the conventional treatment method of discharging a sludge from the settling tank, it is possible to reduce the amount of generated sludge remarkably and consequently, reduce a sludge disposal fee, the use amount of slaked lime, and a running cost such as maintenance cost of a dehydrator.

Abstract: Fluorine-containing water is treated by contacting the fluorine-containing water with calcium carbonate to react the fluorine in the fluorine-containing water with the calcium carbonate and fix it as calcium fluoride. After the fluorine-containing water is contacted with the calcium salt in the reaction tank to react the fluorine in the fluorine-containing water with the calcium salt and fix it as calcium fluoride, it is subjected to solid/liquid separation, and the treated water is removed while a portion of the sludge concentrated by the solid/liquid separation is returned to the reaction tank.

Abstract: A process for reducing boron and/or fluoride ion content of water. Feed water is contacted, in the presence of magnesium, with an alkaline hydroxide to produce treated water and a magnesium precipitate containing boron and fluorine. The precipitate is separated from the treated water. The boron content of water is reducible from above about 0.8 mg/L to below about 0.7 mg/L, and the fluoride ion content is reducible from above about 1 mg/L to below about 0.9 mg/L. The magnesium precipitate is optionally used to neutralize pressure oxidized ore slurry or roaster calcine in the context of gold recovery operations.

Abstract: In a fluoride including waste water processing device which comprises a reaction vessel and a sedimentation vessel, a calcium compound adding device adds calcium compound in fluoride including waste water in the reaction vessel to react the calcium compound with fluoride of the fluoride including waste water to generate calcium fluoride. The sedimentation vessel has a bottom which is associated with a bottom of the reaction vessel through an opening hole. The fluoride including waste water is sent to the sedimentation vessel from the reaction vessel through the opening hole. The sedimentation vessel has an inclined bottom surface. The calcium fluoride is sent back, by a self-weight of the calcium fluoride, to the reaction vessel from the sedimentation vessel along the inclined bottom surface. An agitator aggregates the fluoride including waste water in the reaction vessel. A polymer solution adding device adds polymer solution in the fluoride including waste water in the reaction vessel.

Abstract: Waste water containing fluorine, nitrogen and organic matter is treated by introducing the waste water into a water tank filled with calcium carbonate mineral and anaerobic microorganic sludge. An upper portion of the water tank is occupied by the anaerobic microorganic sludge concurrently with natural precipitation of the calcium carbonate mineral toward a lower portion of the water tank. Calcium ions dissolving from the calcium carbonate mineral precipitated in the lower portion of the water tank are made to chemically react with the fluorine in the waste water. At the same time, the organic matter in the waste water is treated by utilizing anaerobic microorganisms in the anaerobic microorganic sludge in the upper portion of the water tank. The nitrogen in the waste water is treated to be reduced by reducibility that the anaerobic microorganisms in the waste water own.

Abstract: The present invention provides a crystallization process for removing fluoride from waste water. Fluoride-containing waste water is introduced into a fluidized bed crystallizer provided with a carrier. A water soluble sodium reagent and a water soluble aluminum reagent are added into the fluidized bed crystallizer to form crystallized cryolite (Na3AlF6) onto the carrier. The treated waste water is separated from the fluidized bed crystallizer to obtain a primary treated water. The formed cryolite is in the form of crystals, which contain about less than 10% water, and is very convenient for re-utilization.

Abstract: This waste water treatment equipment introduces granular calcium carbonate mineral 13, a calcium fluoride 14 in a floc form and a microorganism 15, which are flowing in a lower section 8, into an upper section 7 and sprinkles the same. Therefore, in the upper section 7, the granular calcium carbonate mineral 13 chemically treats fluorine in an exhaust gas, while the calcium fluoride 14 in the floc form chemically treats acid components in the exhaust gas although the effect is little. At the same time, the microorganism 15 biologically treats the organic matter in the exhaust gas. Then, the granular calcium carbonate mineral 13, the calcium fluoride 14 and the microorganism 15 that have not been utilized for exhaust gas treatment treat again the waste water in the lower section 8.

Abstract: A process for removing fluoride from wastewater is presented. Calcium (or magnesium), sodium and aluminum reagents are added into a fluidized bed crystallizer to remove most of the fluoride in wastewater. The remaining fluoride is removed by aluminum hydroxide. Alternatively, two fluidized bed crystallizers are used in series to treat the fluoride-containing wastewater: in the first fluidized bed crystallizer, calcium (or magnesium), sodium and aluminum reagents are used to treat the wastewater which contains high concentrations of fluoride, so that the fluoride concentrations thereof are largely reduced. Then, in the second fluidized bed crystallizer, a calcium reagent is added to further remove fluoride therein.

Abstract: To remove the olefinic impurities from a hydrochlorofluoroethane of formula: CF.sub.3 --CHClX (X=H, F, or Cl), it is subjected to a photochlorination stage.

Abstract: A process and system for removing heavy metals, fluoride, silica and other contaminants from large volumes of wastewater is disclosed. In the process, a wastewater stream containing the contaminant is treated with a chemical coagulant to create a particle having a diameter greater than 5 microns. Treated wastewater is passed through a microfiltration membrane which physically separates the metal contaminant particle from the wastewater. Commercially available microfiltration membranes having a pore size from 0.5 micron to 5 microns may be used. The treated wastewater flow rate through the microfiltration membranes can range from 700 gallons per square foot of membrane per day ("GFD") to 1500 GFD. Solids are removed from the membrane surface by periodically backflushing the microfiltration membranes and draining the filtration vessel within which the membranes are located. The dislodged solid material within the filtration vessel is flushed into a holding tank for further processing of the solids.

Abstract: This invention relates to a process for the decomposition of material selected from the group consisting of organic compounds, inorganic compounds, or combinations thereof to compounds which are environmentally acceptable, or are amenable to further degradation by conventional disposal systems to produce environmentally acceptable products, which process comprises: (a) conveying an aqueous solution or an aqueous slurry of material into a reaction zone capable of withstanding the temperatures and pressures of decomposition of the material; (b) contacting the material in the reaction zone with aqueous sodium carbonate as a reactant in an amount effective to decompose the material under hot water or supercritical water oxidation conditions of between about 300.degree. and 600.degree. C. and a pressure of between about 20 and 400 atmospheres for between 0.

Abstract: A process for removing dissolved fluorides from an aqueous stream using at least two reactors wherein the dissolved fluoride containing aqueous feed and an unreacted aluminum containing sludge are combined in the first reactor to give a first reactor admixture after which the first reactor effluent stream is directed to the second reactor and therein combined with fresh alum and fresh sodium aluminate to give a second reactor admixture comprising a reduced fluoride aqueous solution and a partially reacted aluminum containing sludge and thereafter recovering the reduced fluoride aqueous solution and recycling at least a portion of the aluminum containing sludge to the first reactor.

Abstract: A composition for treating water or flue gases that contains metal ions and possibly also organic and/or inorganic compounds is produced by reacting sulfur with an alkali- and/or alkaline earth metal hydroxide in the presence of water.The inventive composition corresponds to general formula IM.sub.x S.sub.y O.sub.z, (I)where M represents an alkali or alkaline earth metal,x is 1 or 2,y is in the range 0.5x-4.0x, andz is in the range 0.1-2.5.Alkali sulfite salts, particularly sodium salts, may also be added to the compound for reducing H.sub.2 S emission.

Abstract: The invention relates to the treatment of waste water containing a harmful ion such as a heavy metal ion or fluorine ion by the coagulating sedimentation method using an inorganic coagulant such as an iron compound or an aluminum compound. After separating treated water from the sediment (sludge) in which the harmful ion is incorporated in insoluble form, the pH of a mixture of the sediment and water is suitably adjusted to cause elution of the harmful ion from the sediment. Then the sediment is separated from the eluate and reused as an inorganic coagulant. By reusing the sediment in this manner, the waste water treatment is accomplished without producing a large quantity of sludge and the consumption of inorganic coagulant and auxiliary chemicals can be greatly reduced, while the concentration of the harmful ion in the treated water becomes sufficiently low.

Abstract: This invention relates to a process for the decomposition of material selected from halogenated organic compounds, to compounds which are environmentally acceptable, or are amenable to further degradation by conventional disposal systems to produce environmentally acceptable products, which process comprises: (a) conveying an aqueous solution or an aqueous slurry of material into a reaction zone capable of withstanding the temperatures and pressures of decomposition of the material; (b)contacting the material in the reaction zone with aqueous sodium carbonate as a reactant in an amount effective to decompose the material under hydrothermal oxidation conditions of between about 300.degree. and 400.degree. C. and a pressure of between about 20 and 400 atmospheres for between 0.

Abstract: A first reaction/adjustment tank has a lower portion containing a calcium carbonate mineral, an upper portion containing a calcium carbonate mineral and a plastic filler, and an air lift pump for circulating waste water from the lower portion to the upper portion. Exhaust gas is introduced into a space. A second reaction/adjustment tank has a lower portion containing a calcium carbonate mineral and charcoal, and an upper portion containing charcoal and a plastic filler. Waste water circulates sequentially through the lower and upper portions of the first reaction/adjustment tank, and the lower and upper portions of the second reaction/adjustment tank. Exhaust gas circulates sequentially through the upper portion of the first reaction/adjustment tank and the upper portion of the second reaction/adjustment tank.