Abstract: The present invention relates to a process for treating a wastewater comprising an ammonium ion species and a phosphorus ion species. The process comprises the steps of: (i) treating the effluent in a first stage of the process to convert the phosphorus to a phosphorus-containing salt; (ii) treating the wastewater in a second stage of the process to convert the ammonium ion species to gaseous ammonia; (iii) removing the struvite and/or other phosphorous containing salts from the effluent; and (iv) removing the gaseous ammonia from the wastewater.

Abstract: A method for reducing the total concentration of barium in a source of ground water, such that the water can safely be returned to the watershed or used for drinking water, is described. The present method includes extracting the water from a source thereof, and contacting the water with an effective amount of sulfuric acid. The method has the additional benefits that it simultaneously reduces the pH of the water as well as reducing the concentration of bicarbonate ions. An example of water often having total barium concentrations too high for release into the watershed, includes water extracted during coal-bed methane production.

Abstract: The invention provides compositions comprising bauxite refinery residues that have been reacted with sufficient calcium and magnesium ions that they have a reaction pH of less than 10.5, and one or more water treating additives. The invention also provides processes for treatment of water containing dissolved inorganic substances involving stepwise treatment of the water in which the reacted bauxite refinery residues are added after the addition of a pH-raising additive. The invention also provides processes for treatment of water containing dissolved inorganic substances in which the reacted bauxite refinery residues are added stepwise, with one or more water treating additives also being added in at least one of the steps.

Abstract: This invention relates to a method for treating acidic waste water, particularly mine effluent, and to a solid waste water treating material useful for the method. This waste water treating material is obtained by solidifying a mixture of rock wool and an inorganic binder mainly containing at least one kind selected from silicates, hydroxides and oxides of alkaline earth metals and alkali metals and has a porosity of 50% or more. When brought into contact with acidic waste water containing iron ions and sulfate ions, this waste treating material can not only neutralize the waste water but also remove harmful heavy metals such as iron and arsenic. Furthermore, it is easy to dispose the spent waste water treating material.

Abstract: A method of removing arsenic from water by using a reactor that is provided with a fluidized bed of carriers is disclosed. An arsenic-containing influent is mixed in the reactor with a sulfide aqueous solution or metallic salt aqueous solution at a predetermined pH, thereby resulting in formation of crystals of arsenic sulfides or arsenic acid metal salts. The arsenic contained in the influent is thus removed by crystallization. An effluent with a reduced arsenic content is discharged from the reactor. The carriers, on which the crystals are formed, are periodically removed from the reactor which is replenished with fresh carriers immediately after.

Abstract: A water stream containing hardness minerals is subjected to a water treatment process using an alkali agent to precipitate the hardness minerals and to produce a softened water stream is used to create an integrated water treatment and flue gas desulfurization process. Thereafter, the softened, alkaline water stream is utilized in a scrubber to scrub a flue gas containing sulfur dioxide to produce a sulfur-lean flue gas. The invention may be applied to a steam-based bitumen recovery operation where bitumen, sour produced gas or other sulfur containing fuels are burned for producing steam for bitumen recovery. More specifically, the associated produced water from the bitumen recovery process may be softened for re-use and for utilization as a scrubbing agent for high-sulfur containing flue gas arising from the steam generators. The process provides an economically favorable process while minimizing waste disposal requirements.

Abstract: An apparatus and method for on-site treatment and reclamation of oil and gas well waste water or fracturing fluids. The mobile treatment process and apparatus provide both chemical precipitation and filtration to treat the drilling fluid waste to a technically and environmentally acceptable level allowing for reuse. Alkaline treating agents are applied to the drilling waste fluids, as they are pumped through the treatment apparatus, to increase the pH of the fluid waste to a preferred pH range and to also cause selective soluble contaminants in the fluids to form a precipitate. The waste fluid is allowed to clarify as the precipitate of insoluble contaminants, through flocculation, settle and form a sludge at the bottom of the drilling pit. The clarified fluids are then filtered to satisfy applicable industry and environmental requirements.

Abstract: A filtering method is directed to a wastewater of CMP process, which includes sub-micrometer particles suspended as colloid. The wastewater is filtered by a gel membrane formed on a surface of plastic filter. A coagulant or a pH adjuster is added to the wastewater so that the sub-micrometer particles are coagulated to form the gel membrane.

Abstract: Pollutants, such as heavy metals, phosphorus, and pathogenic organisms, are removed from water by adding a chemical coagulant to the water within an enclosure. The water and the coagulant are mixed, and coagulation and flocculation are permitted to occur. The mixing is stopped, and a floc is permitted to settle to the enclosure bottom. The floc contains the pollutant; so the treated water above the floc is free from at least some of the pollutant. At least some of the treated water is removed from the enclosure, and new water is added to the enclosure. The new water and the settled floc are mixed to resuspend components of the floc. The process is repeated for multiple iterations, until the floc no longer exhibits contaminant-removal capability, at which time the floc is removed from the enclosure.

Abstract: An apparatus and method for removing phosphorus from a wastewater effluent stream from a hog waste lagoon. The wastewater effluent is introduced to the bottom of an inverted cone-shaped continuous crystallizer including a fluidized bed of struvite therein. An effective amount of ammonia is introduced to the wastewater effluent at the bottom of the crystallizer to elevate the pH of wastewater effluent a predetermined amount. An effective amount of magnesium is also introduced to the wastewater effluent at the bottom of the crystallizer. The composition adjusted wastewater effluent is then continuously passed upwardly through the fluidized bed of struvite to reduce the total phosphorus content of the wastewater effluent a predetermined amount of up to about 80% or more. The treated wastewater effluent stream is removed from the top of the crystallizer, and struvite crystals that grow large enough to sink from the bottom of the crystallizer are periodically removed from a collection chamber therebeneath.

Abstract: Methods of treatment of fluids produced by an oil or gas well following a stimulation operation, allowing separation from the fluids and re-injection of oil and gas hydrocarbons in a production pipeline under pressure, and allowing achievement of suitable quality for the residual fluids compatible with their rejection, for example into the sea, including the following three elements; neutralization of the fluids by mixing with a high pH chemical, until the resulting pH reaches a level compatible with the equipment and pipes; use of optimized emulsion breakers in a phase separator, selected for best results with the fluids produced by the well, to accelerate the separation of oil from the fluids, and to lower the residual oil content in the fluids to levels compatible with environmental regulations; and use of a multi-phase pump to pump the oil and gas hydrocarbons produced and reinject them in a pipeline under pressure.

Abstract: The levels of iron sulfide present in a conduit, such as a pipeline, are reduced by contacting the conduit, on an inner surface, with a composition obtained from an aqueous solution containing at least one compound of Formula (I) and at least one amine or corresponding ammonium derivative in the presence of a solvent, wherein X is an anion of valency n. Preferably, the pH of the solution is about 8. Alternatively, the method employs a composition comprising tris(hydroxymethyl)phosphine (TRIS) and at least one amine or corresponding ammonium derivative. The amine preferably is ammonia or a primary alkylamine. The compositions readily complex and thereby dissolve deposits of iron(II) sulfide, removing them from the conduit.

Abstract: The present invention provides a process for removing metals from aqueous solutions. This process entails contacting the aqueous solution with at least one neutralizing agent and at least one precipitating agent that preferentially precipitates metals from the aqueous solution. The neutralizing agent is a lithic material that neutralizes the acidity of the aqueous solution to promote the precipitation of metals form the aqueous solution. The precipitating agent is a lithic material that serves as a preferred locus of deposition for the metals precipitated by the neutralizing agent, i.e. those metals precipitated form the aqueous solution during neutralization.

Abstract: A method of treating wastewater to increase effluent volatile fatty acid content consisting of providing wastewater to a primary treatment vessel and adding a select quantity of a chemical, typically an aluminum or iron salt, to the wastewater, enhancing the separation of organic matter. Separated organic matter is then removed from the chemically treated wastewater forming a primary sludge and a primary effluent. A portion of the primary sludge is fermented to form a volatile fatty acid rich liquor. The volatile fatty acid rich liquor may then be used with the primary effluent, directed to a bioreactor, thereby forming a volatile fatty acid enriched bioreactor feed. The volatile fatty acid enriched influent may be further treated through known biological phosphorous and nitrogen removal methods.

Abstract: A process for removing metal sulfates from dilute aqueous solutions in which a conductivity control solution is injected into the stream. The solution is selected to increase the conductivity of the stream to a value wherein the ion state of each metal is then modified by passing the stream between electrodes of each pair of an array of pairs of electrodes. A voltage is imposed across each pair of electrodes, selected according to a target ion state for each of the various contaminants. The pH of the stream is then increased to a value where precipitate of metal hydroxide of the metal sulfates are formed. The precipitated metal hydroxide is then removed from the stream leaving a reduced amount of sulfate ions.

Abstract: A method for neutralizing in situ pore water associated with a subsurface waste material body, the pore water having a pH of less than 2, the method includes the steps of adding a non-carbonate alkali to the pore water to produce a pH-modified acidic pore water having a pH between about 4 and about 5; and adding a carbonate alkali to the pH-modified pore water in an amount sufficient to raise the pore water pH to between about 6 and about 8.

Abstract: This invention relates to a method for treating soybean refinery wastewater. More particularly, this invention relates to a method for treating soybean refinery wastewater with an aqueous iron salt solution to produce purified water. An aqueous iron salt solution is admixed with soybean refinery wastewater, the resulting mixture is agitated and passed through at least one filter device to form a filtered effluent, and the pH of the filtered effluent is adjusted to a value below about 8 to form purified water.

Abstract: The present invention is directed to a method and apparatus for the treatment of water and wastewater. In one embodiment, a method of treating water according to the present invention includes mixing sludge and precipitant with the water to be treated, mixing ballast with the water, and separating the water into treated water and sludge. Some or all of the separated sludge may be recycled for mixing with the precipitant and water to be treated.

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: A product and method for the removal of pollutant heavy metals from aqueous solutions which precludes the end user from storing, handling, feeding and controlling hazardous soluble sulfide materials. The product is a slurry which includes a mixture of a liquid medium and an essentially insoluble salt wherein the salt is the reaction product of heavy metal ions, preferably selected from Mn++ ions, Fe++ ions, and Fe+++ ions, and sulfide ions derived from soluble sulfide sources such as sodium sulfide, hydrogen sulfide, and sodium hydrosulfide. Addition of the subject slurry to a wastewater stream will effect the precipitation of heavy metals with lesser equilibrium sulfide ion concentrations than that of the essentially insoluble salt. Solids collected by this method may be returned to subsequent wastewater streams for additional removal of heavy metals by any excess heavy metal sulfide salt.

Abstract: Wastewater treatment systems and processes for: removal of solids, pathogens, nitrogen, and phosphorus from municipal and agricultural wastewater include nitrification of wastewater and increasing the pH of the nitrified wastewater by adding a metallic-containing salt and hydroxide to precipitate phosphorus to form a useable effluent having a specified nitrogen:phosphorus ratio that is useful as a fertilizer or spray for remediation of contaminated soils. The presence of infectious microorganism such as enteropathogenic bacteria and picarnoviruses will be reduced in the useable effluent. The precipitated phosphorus is recovered and used to form useable phosphorus products.

Abstract: The invention provides a method treating acid raw water including the step of neutralising the water by adding calcium carbonate to it in a neutralising stage. The neutralised water is then rendered alkaline or more alkaline by adding an alkali thereto selected from calcium hydroxide, calcium oxide and mixtures thereof in a lime treatment stage. The alkaline water is then treated with carbon dioxide in a carbon dioxide treatment stage, with the carbon dioxide reacting in the carbon dioxide treatment stage with calcium hydroxide dissolved in the water.

Abstract: Process for selectively removing molybdenum from liquid mixtures containing it, in a quantity greater than (200) mg/l, together with vanadium characterized in that it comprises the following steps: bringing the liquid mixture to a pH of less than (3); adding a solution of an alkaline xanthate to the solution so that the molar ratio molybdenum/alkaline xanthate ranges from (¼) to (⅛), maintaining the pH constant by means of the addition of an inorganic acid; stirring the mixture causing the precipitation of the molybdenum present in the mixture.

Abstract: A method of treating spent alkaline pulping liquor (black liquor) includes the steps of providing black liquor containing lignin, and acidulating a phosphate containing material, wherein phosphoric acid is generated by the acidulating step. The black liquor is mixed with phosphoric acid from the acidulated phosphate containing material, wherein lignin is separated and clarified liquor results. The method can include the step of adding a water soluble, surface active, polymeric, coagulant agent to the black liquor before mixing with the phosphoric acid from the phosphate containing material. The clarified liquor comprises anion species including phosphate.

Abstract: Nickel and lead ions are eliminated from an acidic concentrated iron(II) salt solution by adding an alkali sulfide and precipitating nickel and lead sulphides.

Abstract: Systems for removing arsenic from water by addition of inexpensive and commonly available magnesium oxide, magnesium hydroxide, calcium oxide, or calcium hydroxide to the water. The hydroxide has a strong chemical affinity for arsenic and rapidly adsorbs arsenic, even in the presence of carbonate in the water. Simple and commercially available mechanical systems for removal of magnesium hydroxide particles with adsorbed arsenic from drinking water can be used, including filtration, dissolved air flotation, vortex separation, or centrifugal separation. A system for continuous removal of arsenic from water is provided. Also provided is a system for concentrating arsenic in a water sample to facilitate quantification of arsenic, by means of magnesium or calcium hydroxide adsorption.

Abstract: A method of removing arsenic from water by using a reactor that is provided with a fluidized bed of carriers is disclosed. An arsenic-containing influent is mixed in the reactor with a sulfide aqueous solution or metallic salt aqueous solution at a predetermined pH, thereby resulting in formation of crystals of arsenic sulfides or arsenic acid metal salts. The arsenic contained in the influent is thus removed by crystallization. An effluent with a reduced arsenic content is discharged from the reactor. The carriers, on which the crystals are formed, are periodically removed from the reactor which is replenished with fresh carriers immediately after.

Abstract: A method for removing dissolved arsenic from an aqueous medium comprising adding lime to the aqueous medium, and adding one or more sources of divalent metal ions other than calcium and magnesium to the aqueous medium, whereby dissolved arsenic in the aqueous medium is reduced to a lower level than possible if only the step of adding lime were performed. Also a composition of matter for removing dissolved arsenic from an aqueous medium comprising lime and one or more sources of divalent copper and/or zinc metal ions.

Abstract: This metal containing waste water treatment method introduces a metal containing waste water from above into a submerged membrane separation tank 1 in which a reaction section 2, a submerged membrane section 3 having a submerged membrane 5 and a precipitation section 4 are arranged in order from top to bottom, causes a reaction by adding a pH adjuster to the reaction section 2, subsequently separates water from metal by the submerged membrane 5 of the submerged membrane section 3 and subsequently precipitates and concentrates the metal in the precipitation section 4. As described above, according to this treatment method, the pH adjuster is added to the reaction section 2, and therefore, solid-liquid separation can be effected by the submerged membrane 5 with a hydroxide formed. Moreover, the metal can be precipitated and concentrated by the action of gravity without using energy in the precipitation section 4.

Abstract: A system is provided for removing dissolved metals from industrial wastewater by electrocoagulation. The system includes an electrocoagulation reactor with a DC power supply having an insulation support enclosure with positive and negative electrode plates disposed thereon. The electrode plates are insulated for each other but remain in direct contact with the wastewater as it flows between the electrodes. The DC power supply induces opposite charges on alternate electrodes thereby generating an electric field between adjacent electrodes to cause the electrodes to ionize and go into solution for interaction with the contaminants in the wastewater as it flows through the reactor. The reactor is housed in a pressure vessel container so the exterior pressure on the reactor is higher than its internal pressure preventing leakage of fluids and oxygen and hydrogen gases produced in the reactor by decomposition of water.

Abstract: This invention relates to a method for treating acidic waste water, particularly mine effluent, and to a solid waste water treating material useful for the method. This waste water treating material is obtained by solidifying a mixture of rock wool and an inorganic binder mainly containing at least one kind selected from silicates, hydroxides and oxides of alkaline earth metals and alkali metals and has a porosity of 50% or more. When brought into contact with acidic waste water containing iron ions and sulfate ions, this waste treating material can not only neutralize the waste water but also remove harmful heavy metals such as iron and arsenic. Furthermore, it is easy to dispose the spent waste water treating material.

Abstract: The present invention relates to anaerobic curing impregnation sealant compositions which are readily separable from water upon mixing.

Abstract: A simplified process for the partial purification of contaminated phosphoric acid plant pond water having a molar calcium plus magnesium to fluorine ratio greater than or equal to about 0.60, is described, in which the pond water is treated with a basic compound, 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: 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: This invention relates to a novel process for treating and removing undesirable impurities from oil and gas well fracturing fluid. A method for treating fracturing water comprising: (a) passing contaminated fracturing water containing solids and liquid through a mechanical separator to remove solids from the liquid; (b) treating the fracturing water liquid with an alkaline agent to increase the pH of the liquid to a level of above 9; (c) adding a coagulant to the fracturing water to form an agglomerate and separating the agglomerate from the fracturing water; (d) reducing the pH of the fracturing water of step (c) to a level of less than about 5.5; and (e) adding an oxidizing agent to the fracturing water of step (d) to oxidize oxidizable impurities in the fracturing water.

Abstract: A method for pretreating waste water for use in reverse osmosis filtration is provided. Small amounts of chemicals are added to the waste water to promote formation of filterable particles from colloidal and dissolved solids. These particles are then removed via a closed-end, low pressure, high flowrate filtration system prior to reverse osmosis treatment.

Abstract: A method for removing metal contaminants from acidic mine wastewater using lignin derivatives, such as lignosulfonates and kraft lignin, an alkali coagulant, such as a lime compound, and an alkaline composition for increasing the pH. The lignin derivatives are dispersed in the wastewater and the coagulant is added, increasing the pH to about 4.5-8.5 and causing the formation of a floc. The alkaline composition is then added to bring the pH to about 9 to 10, causing the further formation of a floc. Optionally, air oxidation is carried out, reducing the pH to about 8.1-8.6. Optionally, a ferric or ferrous salt may also be added. The flocs comprise metal-lignin colloids, metal hydroxides and metal salts. The flocs coagulate to form a sludge. Optionally, fly ash or diatomaceous earth may be added to increase the density and stability of the sludge. The sludge that is formed contains the metals and is separated from the treated water by filtration.

Abstract: A method of treating an electroless plating waste is provided. The waste is contained and an ability of a reducing agent to reduce a metal of the waste is decreased, for example by adding a stabilizing chemical or by exposing the waste to an anode to which a positive voltage is applied. Poisonous and explosive gases evolve from the waste, which are vented. Upon completion, the waste is drained.

Abstract: The present invention relates to heat curing impregnation sealant compositions, which are readily separable from water upon mixing.

Abstract: This invention provides a method for reducing phosphorous in a body of water. This method comprises calcining a plurality of rocks and collecting carbon dioxide formed as a result of the calcining process; crushing the plurality of calcined rocks; pumping source water from the body of water into to a plurality of retaining cells; flocculating the phosphorus in the source water by introducing the plurality of calcined rocks into the source water in the retaining cells; settling out a phosphorous precipitate formed by the flocculating act; adjusting the pH level of the flocculated source water to a predetermined range of values by pumping carbon dioxide created by the calcining of the rocks into the source water to created treated water; and transferring the treated water back to the body of water.

Abstract: The invention provides compositions comprising bauxite refinery residues that have been reacted with sufficient calcium and magnesium ions that they have a reaction pH of less than 10.5, and one or more water treating additives. The invention also provides processes for treatment of water containing dissolved inorganic substances involving stepwise treatment of the water in which the reacted bauxite refinery residues are added after the addition of a pH-raising additive. The invention also provides processes for treatment of water containing dissolved inorganic substances in which the reacted bauxite refinery residues are added stepwise, with one or more water treating additives also being added in at least one of the steps.

Abstract: A system to control nutrients, suspended algae, and filamentous algae in lakes, ponds, and estuaries includes a structure for containing macrophytic vegetation. One embodiment segregates a column of water within a body of water desired for remediation and shields the water column from sunlight sufficiently to kill phytoplankton therein, the lysis thereof releasing nutrients. The released nutrients are sequestered, and remediated water is replaced in the water column with water from the body of water. Floating or submerged macrophytes can be introduced in combination with shading and induced water movement to optimize nutrient uptake by the macrophytes. Water column shading may also be achieved by the macrophytes themselves, or by other means. The macrophytes can include floating aquatic plants, such as water hyacinths, submerged aquatic plants, and terrestrial or aquatic plants caused to float artificially. The invention also deals with toxic algae in a safe and sequestered way.

Abstract: Process wherein the vanadium present in the chromium ore chromite is recovered as vanadium pentoxide during the course of the fusion of the chromium ore with alkali and its work-up to produce sodium chromate solution and sodium dichromate.

Abstract: A filtering method is directed to a wastewater of CMP process, which includes sub-micrometer particles suspended as colloid. The wastewater is filtered by a gel membrane formed on a surface of plastic filter. A coagulant or a pH adjuster is added to the wastewater so that the sub-micrometer particles are coagulated to form the gel membrane.

Abstract: A process for dewatering and reducing pathogens in liquid waste sludge having a liquid component and a sludge solids component. Alkaline material is added to the liquid waste sludge. Flocculent may then be mixed with the liquid waste sludge. The liquid waste sludge is then fed into a screw press having a screw. The screw simultaneously heats and dewaters the liquid waste sludge for a sufficient period of time and at a predetermined temperature for the sludge solids component from the screw press to be pasteurized. An apparatus is also provided for carrying out the process for dewatering and reducing pathogens in liquid waste sludge.

Abstract: The present invention is to provide a method for treating a wastewater containing heavy metals using a used iron oxide catalyst, which is to treat an acidic wastewater having a pH value of about 1.0 and containing Cu, Fe, Ni, Cr or Zn, the method including: adding the used iron oxide catalyst containing at least 70% magnetite (Fe3O4) to the wastewater at a weight ratio of 1:0.05; stirring the wastewater mixed with the iron oxide catalyst at a speed of 60 rpm for 15 minutes in a stirrer; and subjecting the wastewater to solid-liquid separation using a magnet for adsorption and removal of the heavy metals.

Abstract: A method is provided for fixing and eliminating fluorine and phosphorus in waste water wherein the waste water includes a fluorophosphate compound in which hydrochloric acid is added to the waste water including the fluorophosphate compound. The waste water to which hydrochloric acid has been added is heated in order to decompose the fluorophosphate compound into hydrogen fluoride and phosphoric acid, while hydrogen chloride gas located within a treating vessel in which the waste water is contained is introduced into a condenser provided outside of the treating vessel, and then a calcium salt is added to the waste water after decomposition in order to fix and eliminate fluorine and phosphorus.

Abstract: A method for treating livestock wastewater includes directing screened wastewater to a hydrocyclone/separation tank system. The hydrocyclone directs the wastewater stream in a generally helical fashion to create bubble-particle aggregates. Activating chemicals can be added to the wastewater upstream of the hydrocyclone or within the hydrocyclone itself. The wastewater is channeled from an outlet of the hydrocyclone through a diffuser to a separation tank, where the bubble-particle aggregates are separated as they rise and accumulate on a free liquid surface of the tank. The treated wastewater settles below the bubble-particle aggregate accumulation and is transferred to a reservoir for later use as irrigation water or barn wash water. Salts may also be removed from the wastewater by filtering the wastewater through salt-removing filters before the wastewater is transferred to the reservoir.

Abstract: In accordance with the present invention, a basic material, preferably ammonia, is injected into the stream of soot water leaving the gasification reactor prior to being processed in a filtration-type soot removal unit. The elevated pH of the soot water causes more metals to remain in the filter cake. Thus, the metals content of the grey water is reduced. More grey water can then be recycled back to the gasification unit, with less grey water being handled by the wastewater treatment unit.

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.