Processes for treating aqueous solutions to remove dissolved selenium species, for example in the presence of an excess of sulphate anions, which include the use of strongly basic anion exchange resins, or co-precipitation and adsorption of the selenate (and selenite) with mixed ferrous and ferric iron, or combinations thereof. Co-precipitation and adsorption of selenate may take place in an electrolytic cell in the presence of ferrous and/or ferric iron.
C02F 9/04 - Traitement en plusieurs étapes de l'eau, des eaux résiduaires ou des eaux d'égout une étape au moins étant un traitement chimique
B01J 41/00 - Échange d'anionsUtilisation d'une substance comme échangeur d'anionsTraitement d'une substance en vue d'améliorer ses propriétés d'échange d'anions
B01J 49/00 - Régénération ou réactivation des échangeurs d'ionsAppareillage à cet effet
C02F 1/28 - Traitement de l'eau, des eaux résiduaires ou des eaux d'égout par absorption ou adsorption
C02F 1/42 - Traitement de l'eau, des eaux résiduaires ou des eaux d'égout par échange d'ions
C02F 1/461 - Traitement de l'eau, des eaux résiduaires ou des eaux d'égout par des procédés électrochimiques par électrolyse
C02F 1/50 - Traitement de l'eau, des eaux résiduaires ou des eaux d'égout par addition ou emploi d'un germicide, ou par traitement oligodynamique
2.
PROCESSES FOR PRODUCING H2S USING SULPHUR-REDUCING BACTERIA
There is provided a process for producing H2S comprising: a) continuously providing an electron donor at a variable rate to a biosolution comprising sulphur reducing bacteria; b) reacting elemental sulphur with HS to from soluble polysulphide; c) providing said polysulphide to a bioreactor having the biosolution, thereby producing H2S gas in the bioreactor; and d) continuously removing H2S gas from the bioreactor, wherein an average rate of providing polysulphide to sulphur reducing bacteria is equal to an average rate of polysulphide consumption by the sulphur reducing bacteria.
The invention provides waste water treatment processes utilizing an ion exchange resin to remove sulphate anions, while adjusting the pH of the ion exchange loading solution with carbon dioxide gas. The effect of the resin loading reactions is that dissolved sulphate is replaced with sequestered carbon dioxide gas, in the form of dissolved bicarbonate, in the treated water and the cations are not removed from the solution.
C02F 1/42 - Traitement de l'eau, des eaux résiduaires ou des eaux d'égout par échange d'ions
B01D 15/04 - Procédés de séparation comportant le traitement de liquides par des adsorbants ou des absorbants solidesAppareillages pour ces procédés par des substances échangeuses d'ions comme adsorbants
The invention provides hydrometallurgical processes by which dissolved nickel may be removed from water at ambient temperature and low system pressure The continuous process for precipitating nickel ions from a pregnant aqueous solution comprises contacting the pregnant solution with a dissolved sulphide in a contactor to form solid nickel sulphide under contactor conditions that comprise a contacting temperature of between 0 and 5O0C, a contacting pressure of between 0 5 and 1 5 atmosphere, and a contacting pH of between 6 and 9, separating the solid nickel sulphide from the pregnant solution to provide a nickel sulphide sludge and a barren water solution, wherein the nickel sulphide sludge has a mean nickel particle size of at least 5 microns and the barren water solution has a dissolved nickel concentration of less than 10 parts per million, and recycling at least a portion of the nickel sulphide sludge to the contactor
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