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: 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 of flocculating and dewatering an aqueous suspension of suspended solids comprising, introducing into the suspension, (a) substantially linear polymer, (b) structured polymer, characterised in that the polymers are introduced into the substrate sequentially. The process brings about improvements in filtration.

Abstract: A method for the reduction of soluble aluminum species in an evaporated salt alkali metal halide brine containing up to 500 ppb aluminum species to provide a brine feedstock suitable for use in a chlor-alkali membrane cell process, said method comprising treating said brine with a magnesium salt in an amount to provide a Mg to Al molar ratio selected from 5-20 to 1 at a Mg concentration selected from 0.5-10 ppm, and sufficient alkali metal hydroxide to provide an excess alkalinity concentration of between 0.1-0.5 g/L alkali metal hydroxide to effect precipitation of a magnesium aluminum hydroxide complex; and removing said complex to provide said brine feedstock.

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

Abstract: Systems and methods for polymer addition control for sludges from water and wastewater treatment. In a treatment process where flocculating agents are used to promote solids aggregation, intrinsic physical properties of the liquid rich stream following separation may be continuously measured in order to control or optimize the amount of flocculating or treatment agent that is added to the process. These intrinsic physical properties may include, for example, the flocculating suspension or network strength. By determining the floc strength using various treating agent dosages, a optimum treating agent dose can be determined. The optimum treating agent dosage is the minimum in a floe strength to polymer dose curve.

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: A method is disclosed for treating a flushing solution from an ion exchanger used in electroplating operations by co-precipitating or selectively precipitating out metal hydroxides derived from metal ions from the structures being plated in the electroplating bath, metal ions from the electrodes use in the electroplating bath and metal ions from the plating metal used in the electroplating bath, and a pH raising agent having a cation with a valence of at least 2. After the metals are precipitated out of the flushing solution, the flushing solution is aerated with carbon dioxide to precipitate out the cation from the pH raising agent as a carbonate. The carbonate precipitate is removed from the flushing solution and the resulting solution consists essentially of water that may be recycled for use in the electroplating plant or safely discharged into the environment.

Abstract: Processes for treating iron containing waste streams are provided. According to these processes, metal-containing compounds, particularly iron oxides are produced. These methods may, for example, be used in the processing of the waste streams from the chlorination of titanium-bearing raw materials and involve the use of certain combinations of neutralization and precipitation steps.

Abstract: The presented invention discloses a process to remove low or high concentrations of common or complexed heavy metals from aqueous solutions as well as oily solutions. The process uses a product (8856A), which is a mixture of 80% phosphoric acid (75-80%) and 20% aluminum sulfate (48%). The percentage of aluminum sulfate in 8856A is very critical in providing optimum solid-liquid separation in the settling stage and removing any excess phosphates from the discharge. Heavy metals such as iron, copper, nickel, zinc, chromium and lead are precipitated as metal phosphates. The process is capable of removing all of the metal in the solution because it discloses a longer detention time of two to four hours, which provides sufficient time to breakdown any complexing agents preventing precipitation of the metal. According to the presented invention, metal concentrations in the treated wastewater are decreased to levels below the detection limits.

Abstract: A method of treating industrial wastewaters is provided. Specifically, the wastewater includes one or more organic contaminant materials and is pre-treated prior to filtering by the following steps The pH of the wastewater is adjusted to a pH in the range of about 2 to 6, and a combination of iron salts and peroxide are added to the wastewater and allowed to react for a period of at least about three minutes. Next, the pH of the wastewater is adjusted upwards to a value of at least 7 and precipitating or flocculating agents are added to form an insoluble contaminant bearing compound. The compound is then filtered from the wastewater thereby removing the contaminant materials from the wastewater. This invention is particularly suited for use with single pass flow-through filters, and most particularly suitable for high flow rate single pass flow-through filters.

Abstract: A method is providing for treating waters, such as standing and flowing waters and waste waters, soils, sediments and/or silts. At least one alkaline earth metal peroxide is brought into contact with such waters or the like, especially to effect immobilization of phosphates and heavy metals except manganese and iron therein.

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 two-step chemical precipitation process involving hydroxide precipitation and sulfide precipitation combined with “field separation” technology such as magnetic separation, dissolved air flotation, vortex separation or expanded plastics flotation, effectively removes chelated and non-chelated heavy metal precipitates and other fine particles from water. In the first-step, the non-chelated heavy metals are precipitated as hydroxides and removed from the water by a conventional liquid/solids separator such as an inclined plate clarifier to remove a large percentage of the dissolved heavy metals. The cleaned water is then treated in a second precipitation step to remove the residual heavy metals to meet discharge limits. In the second precipitation step, any metal precipitant more effective than hydroxide for metal precipitation can be used.

Abstract: Methods for rendering a cyanide or cyanide-containing compound substantially insoluble in an aqueous solution or suspension of cyanide-containing materials comprising: mixing a reagent comprising a thiosulfate salt with said solution or suspension; and adding to said material a complexing agent selected from the group consisting of divalent copper salts, divalent iron salts, divalent cobalt salts, activated carbon and mixtures of the foregoing are provided.

Abstract: A method for the treatment of a wiping solution, characterized by including: adding a flocculant to a used wiping solution for flocculation of ink contained in said used wiping solution; filtering said used wiping solution for separation of said used wiping solution into sludge and a filtrate; heating said filtrate to produce distilled water and a concentrated solution; returning said distilled water for recycling to serve as a raw material of a wiping solution; and heating said concentrated solution for separation of said concentrated solution into steam and a solid residue. An apparatus for performing the method of the present invention is also disclosed.

Abstract: The present invention provides a method for chemical addition utilizing adaptive process control optimizations having a combination of expert system(s), neural network(s) and genetic algorithm(s).

Abstract: A treating method and apparatus for treating a manganese containing water by crystalizing and removing a soluble manganese in a water to be treated containing carbonic acid ions by passing the water to be treated as an upward flow through a fluidized bed reaction tower having no support bed and containing manganese sand as a fluidized bed material and by adjusting a pH value of the water to be treated in said fluidized bed. A suspended manganese is also removed together with said soluble manganese in the water to be treated by forming a suspended solid in the water to be treated into a layer on said manganese sand fluidized bed by removing said layer of suspended solid. Further, a desired quantity of the treated water is introduced into the water to be treated for circulatory use.

Abstract: A batch or continuous process for the removal by flocculation of silicon and heavy metal contamination from aqueous waste streams by the addition of an aluminum salt, particularly, aqueous streams recycled as electrolyte in the electrolytic production of alkali metal or alkaline earth metal chlorates. The process is particularly suited to the removal of heavy metals and silicon contamination in an electrolyte recycled to an electrolytic cell subsequent to the removal by crystallization of a chlorate salt. An aluminum salt, such as aluminum chloride, aluminum chlorohydrate, and polyaluminum chlorides including polyaluminum chloride sulfates is effective as a flocculating agent.

Abstract: A method of dewatering a mixture of coal tailings, water and contaminants comprising the steps of (a) providing a tank having a base surface and introducing said mixture of coal, tailings, water, and contaminants to said tank and allowing said coal tailings to settle on said base surface, (b) removing the coal tailings from said base surface of said tank along with water and contaminants and then separating said water and at least some of said contaminants from said coal tailings wherein said separated contaminants are suspended in said separated water, (c) adding an agent selected from one or more of the group consisting of a coagulant and a flocculent to said water and suspended contaminants separated from the coal tailings in step (b), (d) allowing the agent added in step (c) to coagulate or flocculate with the suspended contaminants to form a coagulated or flocculated mass and a quantity of supernatant water, and (e) separating the coagulated or flocculated mass formed in step (d) from the quantity of sup

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: A composition for treatment of water and soils comprises components A. CaCO3, B. at least one compound selected from the group consisting of calcium salts, including CaCl2 and Ca(NO3)2, and inorganic magnesium compounds, C. at least one compound selected from the group consisting of NaHCO3 and KHCO3, wherein the components A and B are present in a molar ratio of from 0.1:1 to 1:1, and wherein the components B and C are present in a molar ratio of from 1:3 to 1:1.

Abstract: Embodiments of the present invention relate to methods and systems for removal of contaminants from aqueous solutions. The methods and systems of these embodiments are particularly suited to removal of arsenic species as well as transition-metals, post-transition-metals, phosphates and other contaminants in aqueous solutions. The methods and systems of embodiments of the present invention provide for the addition of a reagent to a contaminated solution in combination with a pressurization process and a depressurization process. Contaminant particulates and solids produced in these processes may be removed by conventional separation techniques.

Abstract: The invention concerns a method for treating water to abate their content in suspended matter and, as the case may be in parasites, characterised in that it consists in causing said water to pass through at least one sedimentation tank (1) at a treatment speed higher than 20 mph then, through at least a multilayer filter with decreasing size grading (2) at a treatment speed higher than 10 mph. The sedimentation tank used is preferably a sedimentation tank with ballasted floc preferably lamellar.

Abstract: Wastewater treatment processes and preferred systems for practice of the processes, the invention particularly intends the removal of particulates and dissolved materials contaminating the effluent of garment stonewashing, acid washing and similar processes including chlorinated processes, thereby to allow reuse or sewer discharge of water used in such commercial processes. The processes of the invention typically involve initial filtration to remove solid particulates such as pumice, sand, glass beads and the like followed by acidification of the wastewater and contact with a magnesium hydroxide/activated carbon bed, the activated carbon removing organics such as dyestuffs and the like while the magnesium hydroxide precipitates other dissolved materials for subsequent mechanical removal. After treatment with magnesium hydroxide, parcipitating compounds such as iron sulfate and/or ferric chloride are added to precipitate other inorganic substances and dissolved materials.

Abstract: A method for removing accumulated metals from a cleaning solution is provided. After removal of the metals, the cleaning solution can be discharged or recycled. The process manipulates the pH levels of the solution as a means of precipitating solids. Preferably a dual phase separation at two different pH levels is utilized.

Abstract: The invention relates to a process for treating a chromate waste liquid containing an organic acid component. This process includes (a) adding a chromium precipitation accelerating agent containing at least one of a calcium component and a magnesium component, to the chromate waste liquid; and (b) adjusting the chromate waste liquid to having a first pH of 9 or higher, thereby precipitating a chromium component from the chromate waste liquid and thereby reducing a concentration of a dissolved chromium component of the chromate waste liquid.

Abstract: An improved process for the removal of cyanide ion from aqueous dispersions (e.g., aqueous spent cadmium plating solutions or plating rinse water solutions) is provided wherein a source of Fe+2 ion is reacted with a cyanide ion-containing aqueous dispersion at low pH to form a relatively insoluble reaction product complex, whereupon the reaction product is removed by filtration or the like. In preferred practice, the pH of a waste water is adjusted to a level of up to about 2, followed by the addition of ferrous ammonium sulfate.

Abstract: A system and process for removing contaminants from water and wastewater, where the water or wastewater is transformed into purified water that can be discharged to the environment. Wastewater is transported through several stations for purification, including an electrochemical cell. The purification process begins by sending the wastewater to a classifier through an in-line basket strainer. The wastewater stream in the classifier is drawn through a solid-liquid hydrocyclone, which returns the solids to the classifier and sends the remaining liquid to feed tanks. Contaminants that float are removed from the wastewater by skimming from the surface of the feed tank. The wastewater underflow from the feed tanks is pumped directly to the electrochemical cell where it enters into the bottom of the cell, and exits from the top of the cell. The discharge, including coagulated solids, hydrogen gas, and oxygen gas, is mixed with a polymer as well as compressed air just prior to entering a static in-line mixer.

Abstract: A process for the treatment of waste waters containing chemically reducible dissolved organic and inorganic pollutants and suspended mater in particulate or colloidal form. The process comprises of contacting the water with metallic iron or ferrous ions (Fe2+), or mixtures thereof, in the presence of promoter metals, such as Cu, Pd, Pt, Au, Ag, and Ni, or oxides, sulfides and other insoluble compounds of these meals, which catalyze the redox reductions carried out by the iron or ferrous reagents. The production of ferric ions (Fe3+) as a final iron oxidation product allows for the simultaneous coagulation and precipitation of suspended colloidal and particulate solids out of the aqueous phase. In addition to the main reductive reaction scheme, the system performs a multitude of secondary reactions involving the ferrous and ferric ions produced in-situ which allows for the simultaneous removal of specific target pollutants, such as phosphate and hydrogen sulfide.

Abstract: A method is taught for converting metal contaminants in the soil to less toxic forms as well as permitting their removal from groundwater. A first reactive solution comprising ferrous sulfate and an acid selected from the group consisting of sulfuric acid and phosphoric acid is injected to decomplex contaminants and precipitate them as insoluble compounds. A second reactive solution comprising hydrogen peroxide and an acid selected from the group consisting of sulfuric acid and phosphoric acid is then injected to destroy organic liquids and enhance decomplexation. The pH of the first solution may range from 3 to 5, and the pH of the second solution range from 3 to 7, preferably 5 to 7. The process is particularly effective where chromium compounds such as hexavalent chromium are the contaminants.

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: The present invention relates to a process for treating more or less concentrated aqueous effluents, such as processing waters, industrial or urban waste waters, and sludges, in particular sludges derived from these waste waters. The said process comprises at least one step of physical separation of a liquid phase and of a solid phase dispersed in the said liquid phase and at least one addition of chemical conditioning reagents and optionally of antifoaming agents. The process also comprises the injection of carbon dioxide (CO2) into the said aqueous effluents, in an amount which is sufficient to give them a pH of less than 7.8.

Abstract: This invention relates to a process for removing sulphates and calcium from a water stream which includes the steps of: combining the water stream and an amount of amorphous aluminum trihydroxide (Al(OH)3); allowing the formation of ettringite (3CaO.Al2O3.3CaSO4.31/32H2O) as a precipitate; and removing the precipitated ettringite from the water stream.

Abstract: The present invention relates to a method of treating alkaline waste water originating from washing spent oil which has undergone an alkaline treatment with water and which contains organic material. This method can produce water which can be discharged into conventional industrial water treatment facilities or which can be used directly as a base for preparing fertilizers or for preparing an agent for preventing ice formation on road surfaces.

Abstract: A method and apparatus for removing a group of species of metal ions from an aqueous solution to be purified which involves the steps for each species in succession of adjusting the pH of the aqueous solution to a value where hydroxide precipitates of said species in its highest valency state are insoluble, then passing the aqueous solution through an ion state modification cell to raise the valence of the respective species to its highest valency state thus causing the ion specie to form the insoluble hydroxide, then removing the precipitated hydroxide from the aqueous solution by appropriate steps of settling and press filtering. A magnetic field is imposed between the electrodes which improves the efficiency of the ion state modification step.

Abstract: The present invention is directed to a method for removing selenium from a waste stream. The process is a multi-step process that removes selenium from a waste stream in the form of barium selenate and/or barium selenite. In a further step, the barium selenate and/or barium selenite forms a complex precipitate with barium sulfate, which encapsulates the barium selenate and/or barium selenite. The complex precipitate is subsequently removed from the waste stream.

Abstract: A method for removing the oxy-anions of selenium from FGD scrubber purge water. The purge water is contacted with free hydroxyl radicals to effect oxidation of reduced forms of sulfur to sulfate and the destruction of sulfur-nitrogen compounds present in the purge water. The purge water is then subjected to chemical reduction and co-precipitation of selenium with an amount of ferrous ions effective to remove the oxy-anions of selenium in the liquid in less than 30 minutes of reaction time. The resultant ferrous-selenium solids generated are separated and stabilized to elemental selenium in a separate reaction vessel.

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: The present invention relates to an apparatus for removing volatile impurities such as mercury and selenium from a weak acid solution resulting from scrubbing gases created in the production of sulfuric acid by roasting of sulfide concentrates. The apparatus comprises a calcine filtering unit for removing calcine from the weak acid solution, a sodium sulfide mixing unit for precipitating mercury from the weak acid solution, a sodium dithionite mixing unit for precipitating selenium from the weak acid solution, and a mercury-selenium filtering unit for filtering the precipitated mercury and selenium from the weak acid solution. The present invention further relates to a treatment plant utilizing such an apparatus, a process for removing volatile impurities from a weak acid solution, and a selenium cake obtained by utilizing the resent invention.

Abstract: Wastewater streams containing tacky or sticky components and heavy metals, such as photoresist-containing streams from printed-circuit board manufacture and water streams from paint spraying processes, can be detackified and the metals simultaneously removed by addition of a metal salt, such as an iron salt, and a sulfide material. The combination of metal salts and sulfide reacting products produces a detackified metal sulfide sludge that improves the filterability of the wastewater while also removing dissolved metal ions from the wastewater.

Abstract: A method for removing selenocyanate from aqueous waste water containing a reducing agent by adding a water soluble cupric salt, said waste water containing a reducing agent having a potential to reduce the cupric ion to the cuprous ion, and removing the resulting selenocyanate precipitate from said waste water.

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: The present invention relates to a process for treating more or less concentrated aqueous effluents, such as processing waters, industrial or urban waste waters, and sludges, in particular sludges derived from these waste waters. The said process comprises at least one step of physical separation of a liquid phase and of a solid phase dispersed in the said liquid phase and at least one addition of chemical conditioning reagents and optionally of antifoaming agents. The process also comprises the injection of carbon dioxide (CO2) into the said treated aqueous effluents, in an amount which is sufficient to give them a pH of less than 7.8.

Abstract: A process for removing or stabilizing arsenic and/or selenium from aqueous streams or slurries is provided that includes contacting the streams or slurry with a composition containing lanthanum chloride. The lanthanum chloride composition can optionally contain various lanthanides. The composition can optionally contain ferric or ferrous sulfate. The process is preferably conducted by adjusting the pH of solution to between about 8 or 10, adding 2 moles of lanthanum chloride for every mole of arsenic or selenium ions present in solution, adding 5 to 6 moles ferric or ferrous ions for every mole of arsenic or selenium ions present in solution and adjusting the oxidation potential of the solution to between 200-400 mV for removal of selenium ions and between 100-200 mV for removal of arsenic ions.

Abstract: The invention relates to desalination of Sea water and of brakish water, and removal of harmful CO2 gas in exhaust from combustion apparatuses. The exhaust, rich in carbon dioxide (CO2) is diverted to a process chamber, where Sea water, after being mixed with Ammonia, as a catalyst to weaken the salt molecules, is pumped into the chamber and dispersed at many points near the top, as a fine spray, exposing the salt to the CO2 gas there. The internal bond of the salt molecules (NaCl) are weaker by the Ammonia in the water attaching and pulling on their Cl atom. The CO2 in the chamber is attaching and pulling on the Na atom of the salt molecules and are further reduces the bond, breaking them apart. Two heavy solids are formed, they settle in a clarifier below and are removed. Desalinated Sea water, in large quantities per ton of salt, over flows from the clarifier, for use in communities and for agriculture.

Abstract: The present invention relates to a process for the treatment of arsenic-containing sludge obtained by adjusting arsenic-containing waste water to a PH of 12 or greater by the addition of a calcium compound and subjecting the waste water to solid-liquid separation, the process comprising the steps of adding a calcium compound to the arsenic-containing sludge slurry obtained by the solid-liquid separation, dewatering the resulting sludge, drying the dewatered sludge, and calcining the dried sludge. According to the present invention, arsenic-containing sludge obtained by treating waste water to precipitate arsenic present therein can be calcined to yield a calcined product which involves no risk of arsenic redissolution when it is dumped. Moreover, there is no possibility that arsenic compounds may be volatilized during calcination.

Abstract: A method and apparatus for the treatment of wastewater effluent from a laundromat combines multiple filtering, particularly including, bag filters, to remove particulates including fine particulates followed by treatment in a weak base anion exchange resin bed to remove MBAS. The weak base resin was found to remove MBAS and organics such as LAS which were highly de-adsorbed in the efficient regeneration of the resin. The weak base anion exchange resin is preferably macroporous in the sulfate form. The invention contemplates multiple bag filters of different degrees of coarseness.

Abstract: According to the present invention there is provided a method of treating reject from a plant for de-inking waste paper which reject comprises in an aqueous medium a mixture of suspended solids comprising at least ink particles, inorganic particles and fibers, which method includes the steps of (i) chemically treating an aqueous suspension comprising said reject by adding to the aqueous suspension a source of alkaline earth metal ions and a source of carbonate ions to react with the alkaline earth metal ions to form therein a composite particulate material comprising a substantially white insoluble alkaline earth metal carbonate compound precipitated by the said reaction which compound bonds to and entrains material comprising ink particles, inorganic particles and fibers contained in said reject, whereby the darkness of the reject is reduced by formation of the precipitate of the carbonate compound; and (ii) recovering the composite particulate material and delivering the composite particulate material for r

Abstract: A method to remove heavy metals concentrations in water down to very low levels is described. The method calls for the addition of a soluble sulfide to the water. This is followed adding a soluble iron reagent such as ferrous sulfate or ferrous chloride. The water is aerated. As an alternative to aeration, the pH of the water can be increased. Finally, the solids generated from the above steps are separated from the water. This method has been shown to remove heavy metals, particularly copper and zinc, from actual industrial wastewater to very low concentrations, i.e., below about 100 ppb. Furthermore, the treated water is free of sulfide. The byproduct sludge comprises iron sulfide, iron oxides, iron hydroxides, and the heavy metal sulfides.