EP1470082A2 - Method for treating water in order to reduce the metal ion concentration thereof - Google Patents

Method for treating water in order to reduce the metal ion concentration thereof

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Publication number
EP1470082A2
EP1470082A2 EP20030712275 EP03712275A EP1470082A2 EP 1470082 A2 EP1470082 A2 EP 1470082A2 EP 20030712275 EP20030712275 EP 20030712275 EP 03712275 A EP03712275 A EP 03712275A EP 1470082 A2 EP1470082 A2 EP 1470082A2
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EP
European Patent Office
Prior art keywords
water
electrodes
reactor
treated
demetallization
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Application number
EP20030712275
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German (de)
French (fr)
Inventor
Christian J. Meignen
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Individual
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Individual
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Publication date
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Publication of EP1470082A2 publication Critical patent/EP1470082A2/en
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/467—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction
    • C02F1/4676—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction by electroreduction
    • C02F1/4678—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction by electroreduction of metals
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/4602—Treatment of water, waste water, or sewage by electrochemical methods for prevention or elimination of deposits
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/103—Arsenic compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/20—Heavy metals or heavy metal compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/20—Heavy metals or heavy metal compounds
    • C02F2101/203—Iron or iron compound
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/20—Heavy metals or heavy metal compounds
    • C02F2101/206—Manganese or manganese compounds

Definitions

  • the present invention relates to a new water treatment process aimed at reducing its concentration of metal ions.
  • demetallization of water; the term “demetallization” is understood to mean the reduction in the concentration of certain metals in the composition of water and more particularly water intended for human consumption.
  • the state of the art is essentially concerned with iron and with the consequent problem of water iron removal, that is to say a decrease in the concentration of the ions Fe ++ and Fe +++.
  • a process conventionally used for de-ironing water consists of a so-called "physico-chemical" treatment, namely bringing the water to be treated into contact with air in the purpose of oxidizing the Fe ++ ions to Fe +++; it is then possible to see the appearance of amorphous iron oxides, Fe (OF £) 2 and / or Fe (OH) 3 depending on the pH of the water, which should be collected and filtered so as to obtain the de-ironed water desired.
  • Another known method consists in using a biological treatment using a bed of sand seeded with bacteria on which circulates the water charged with ions.
  • Fe ++ and / or Fe +++ said bacteria absorb ionic energy allowing the formation of iron oxides, which are filtered on the sand bed, thus leading to de-ironed water.
  • the invention which is the subject of the present application is located in the field of water treatment and falls into the category of physical processes and more particularly those using micro-electrolysis where the water to be treated constitutes the electrolyte. .
  • French patent n ° 96 00714 describes a process for the production of water lightened in calcium carbonate, of the type where one carries out a micro-electrolysis within water with treat which constitutes the electrolyte, where the electrolysis is accompanied by a phase of electrogermination and a phase of dehydration of the calcium carbonate germs contained in the water thus treated with the aim of constituting crystals of CaCO3.
  • the above-mentioned germination and dehydration are carried out by means of an appropriate electrical energy which generates at the level of the electrodes the dissociation of water into the ions H + and OH-.
  • the present invention relates to a process for demetallization of water, wherein said method consists in carrying out a micro-electrolysis of the treated water which gives both hydroxides OH- and oxidants such as oxygen or chlorine which will directly or indirectly allow demetallization.
  • the anodic metal of the electrodes used for demetallization is the same as that of the electrodes used for the decarbonation of water which is the subject of French patent n ° 96 00714, the demetallization process and that decarbonation can be performed simultaneously or individually.
  • the electrodes used will be specific to a demetallization process applied alone.
  • the present invention also relates to the means used to achieve the desired demetallization and will be better understood on reading the description which follows, made with reference to the figures given by way of example and in no way limiting, among which:
  • FIG. 1 is a diagram showing a device according to an alternative embodiment where both demetallization and decarbonation of the water to be treated are carried out.
  • - Figure 2 is a diagram showing a device according to another alternative embodiment where both demetallization and decarbonation of the water to be treated are carried out.
  • - Figure 3 is a diagram showing a device according to a third alternative embodiment where only demetallization of the water to be treated.
  • the demetallization of water takes place at the same time as its decarbonation.
  • the device used may consist of that of the decarbonation process which is the subject of French patent n ° 96 00714; thus this device shown in Figure 1 may include a reactor (1) of cylindrical or parallelepiped shape, the cathode (s) being formed by the side wall forming the reactor and intermediate walls, the anode (s) being arranged parallel to the axis longitudinal of said cylinder or said parallelepiped.
  • said longitudinal axis will be arranged vertically, the water to be treated arriving in the lower part (2) of the reactor, the treated water being recovered in the upper part (3) of said reactor, the calcium carbonate and the oxide of iron being recovered at the base (4) of this reactor (the electrodes inside the reactor are not shown in this figure).
  • the anode or anodes will be filiform or in the form of plate (s); the, or one of the anodes may also constitute the longitudinal axis of said reactor.
  • the other characteristics of the device, as well as the electrical values (amperage, voltage, frequency) and the water circulation parameters (speed, direction) may be those described in the aforementioned patent; preferably the different ranges of these values will be applied in combination.
  • Ocre calcium carbonate is the result of the present invention in the simultaneous application of demetallization and decarbonation, which allows, thanks to electrical energy to create the different precipitation paths of the "iron” ions contained in the water to be ironed in the form of "carbon” or “oxidized” precipitates.
  • carbonaceous precipitates have the following origin: in the presence of carbonate [HCO3-], of carbon dioxide [CO2], depending on the pH of the water to be treated and its evolution during the reactions, part of the precipitation observed concerns iron carbonates [FeCO3] and / or “carbonic irons” [FeCO2] (siderite). This precipitation together with calcium carbonate [CaCO3] organizes the ocher coloration of the calcium carbonate crystals.
  • the “oxidized” precipitate pathway consists of precipitates mainly resulting from oxidation by nascent oxygen [O2] and / or chlorine [C12] induced by the electro-chlorination of Cl- ions present in water , which are adsorbed on the filtering medium consisting of calcium carbonate from the above-mentioned decarbonation and contributes to the mass coloration of the crystals.
  • the iron content is statistically less than 1% of the [CaCO3] content.
  • the Applicant has also been able to show that a device, no longer of the vertical type, but of the lateral type with the electrodes placed in baffles, also gave good results, the same electrical characteristics (15 ⁇ A - 20 A / m or m 2 of electrodes;
  • the reactor (5) has a horizontal longitudinal axis, the electrodes being made up of plates (6) arranged in a baffle; the water inlet takes place at one end (7) and leaves, after treatment, at the other end (8) of the reactor.
  • the Applicant has found that another device could validly be used, namely a device of transverse type where the electrodes would preferably be made of an openwork material, especially in the form of grids; in this variant, the speed of the water to be treated can reach 20 cm / s.
  • a device of transverse type where the electrodes would preferably be made of an openwork material, especially in the form of grids; in this variant, the speed of the water to be treated can reach 20 cm / s.
  • FIG. 3 where the reactor (9) is provided with electrodes (10), in the form of perforated plates or grids, the water to be treated arriving at one end (11) of the reactor and coming out, after demetallization at the opposite end (12), the circulation of the water therefore takes place transversely with respect to the electrodes (10).
  • the device which is also conventional for recovering metallic precipitates or calcium carbonate, is not shown in FIGS. 2 and 3. It also appeared advantageous to have a filtering element, conventional or membrane with the rest of the device; in addition to this filter element, calcium carbonate can constitute an additional filter element when the process simultaneously allows demetallization and decarbonation.
  • the applicant has not limited itself to the demetallization of water where the metal is iron, that is to say its iron removal. According to the present invention, advantageous results can indeed be obtained for other metals; this is the case for calcium and magnesium (alkaline earth), arsenic (metalloid), manganese, nickel, zinc, chromium, copper and lead. Further studies have been carried out by the applicant concerning three of the metals with the most disadvantages, namely iron, arsenic and manganese; the results below clearly show the advantage of the process used by the applicant.
  • the iron removal process according to the invention making it possible to obtain a rate very much lower than the European standard of 200 ⁇ g / 1 for which the water can however retain an unpleasant taste as well only a slight ocher coloration (for the record, water is said to be “comfortable” if the iron content is less than or equal to 100 ⁇ g / 1, which remains much higher than the rate obtained by the applicant).

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Chemistry (AREA)
  • Water Treatment By Electricity Or Magnetism (AREA)
  • Removal Of Specific Substances (AREA)

Abstract

The invention relates to a method for reducing the concentration of certain metals in the composition of water. Said method consists in carrying out microelectrolysis of the water that makes up the electrolyte, the amperage of the electric current used ranging from15µA and 200 A/m or m2 of electrodes; the voltage advantageously ranging from 20 µ.V and 48 V. According to one embodiment, the device for carrying out said method comprises a reactor (1). The water to be treated arrives in the lower part (2), the treated water is recovered in part (3), the carbonate and calcium and the iron oxide are recovered at the base. The invention can be used for treating water such as water for human consumption.

Description

PROCEDE DE TRAITEMENT DE L'EAU EN VUE D'EN REDUIRE SA CONCENTRATION EN IONS PROCESS FOR TREATING WATER WITH A VIEW TO REDUCING ION CONCENTRATION
METALLIQUESMETAL
La présente invention concerne un nouveau procédé de traitement de l'eau visant à réduire sa concentration en ions métalliques.The present invention relates to a new water treatment process aimed at reducing its concentration of metal ions.
Il sera fait référence dans la présente demande à un procédé de « démétallisation » de l'eau ; le terme « démétallisation » s'entend comme la diminution de la concentration de certains métaux dans la composition de l'eau et tout particulièrement l'eau destinée à la consommation humaine.Reference will be made in the present application to a process of "demetallization" of water; the term “demetallization” is understood to mean the reduction in the concentration of certain metals in the composition of water and more particularly water intended for human consumption.
L'état de la technique s'attache essentiellement au fer et au problème conséquent de la déferrisation de l'eau, c'est à dire d'une diminution de la concentration des ions Fe++ et Fe +++. A cet égard, il convient de rappeler qu'un procédé classiquement utilisé pour la déferrisation de l'eau consiste en un traitement dit « physico-chimique », à savoir la mise en contact de l'eau à traiter avec de l'air dans le but d'oxyder les ions Fe++ en Fe+++ ; il est alors possible de voir apparaître des oxydes de fer amorphes, Fe(OF£)2 et/ou Fe(OH)3 selon le pH de l'eau, qu'il convient de recueillir et de filtrer de façon à obtenir l'eau déferrisée souhaitée.The state of the art is essentially concerned with iron and with the consequent problem of water iron removal, that is to say a decrease in the concentration of the ions Fe ++ and Fe +++. In this regard, it should be recalled that a process conventionally used for de-ironing water consists of a so-called "physico-chemical" treatment, namely bringing the water to be treated into contact with air in the purpose of oxidizing the Fe ++ ions to Fe +++; it is then possible to see the appearance of amorphous iron oxides, Fe (OF £) 2 and / or Fe (OH) 3 depending on the pH of the water, which should be collected and filtered so as to obtain the de-ironed water desired.
Un autre procédé connu consiste à utiliser un traitement biologique mettant en œuvre un lit de sable ensemencé avec des bactéries sur lequel circule l'eau chargée en ionsAnother known method consists in using a biological treatment using a bed of sand seeded with bacteria on which circulates the water charged with ions.
Fe++ et/ou Fe+++ ; lesdites bactéries absorbent l'énergie ionique permettant la formation d'oxydes de fer, lesquels sont filtrés sur le lit de sable, aboutissant ainsi à une eau déferrisée.Fe ++ and / or Fe +++; said bacteria absorb ionic energy allowing the formation of iron oxides, which are filtered on the sand bed, thus leading to de-ironed water.
Ces procédés sus mentionnés peuvent s'appliquer sous certaines conditions, à d'autres métaux tel que le manganèse ; ils comportent toutefois un certain nombre d'inconvénients, compte tenu notamment des autres ions contenus dans l'eau à traiter.These processes mentioned above can be applied under certain conditions, to other metals such as manganese; however, they have a number of drawbacks, especially given the other ions in the water to be treated.
Ainsi, une eau chargée en chlore sera difficilement traitée par le procédé biologique précité, les bactéries utilisées pouvant se révéler très sensibles à ce type d'oxydant au pouvoir bactéricide utilisé pour la désinfection de l'eau destinée à la consommation humaine.Thus, water loaded with chlorine will be difficult to treat by the aforementioned biological process, the bacteria used can prove to be very sensitive to this type of oxidant with bactericidal power used for the disinfection of water intended for human consumption.
L'invention faisant l'objet de la présente demande se situe dans le domaine du traitement de l'eau et se range dans la catégorie des procédés physiques et plus particulièrement ceux utilisant une micro-électrolyse où l'eau à traiter constitue l'électrolyte.The invention which is the subject of the present application is located in the field of water treatment and falls into the category of physical processes and more particularly those using micro-electrolysis where the water to be treated constitutes the electrolyte. .
Le brevet français n° 96 00714 décrit un procédé pour la production d'eau allégée en carbonate de calcium, du type où l'on effectue une micro-électrolyse au sein de l'eau à traiter qui constitue Félectrolyte, où l'électrolyse s'accompagne d'une phase d' électrogermination et d'une phase de déshydratation des germes de carbonate de calcium contenus dans l'eau ainsi traitée dans le but de constituer des cristaux de CaCO3.French patent n ° 96 00714 describes a process for the production of water lightened in calcium carbonate, of the type where one carries out a micro-electrolysis within water with treat which constitutes the electrolyte, where the electrolysis is accompanied by a phase of electrogermination and a phase of dehydration of the calcium carbonate germs contained in the water thus treated with the aim of constituting crystals of CaCO3.
Dans ce procédé, la germination et la déshydratation précitées sont réalisées grâce à une énergie électrique appropriée qui engendre au niveau des électrodes la dissociation de l'eau en les ions H+ et OH-.In this process, the above-mentioned germination and dehydration are carried out by means of an appropriate electrical energy which generates at the level of the electrodes the dissociation of water into the ions H + and OH-.
De façon tout à fait surprenante, il est apparu que le procédé faisant l'objet du brevet français n° 96 00714 pouvait également s'appliquer à la démétallisation de l'eau à traiter, le même procédé pouvant s'appliquer individuellement, simultanément et/ou conjointement à la démétallisation de l'eau et à sa décarbonatation.Quite surprisingly, it appeared that the process which is the subject of French patent n ° 96 00714 could also be applied to the demetallization of the water to be treated, the same process being able to be applied individually, simultaneously and / or jointly with the demetallization of water and its decarbonation.
Plus précisément, la présente invention concerne un procédé de démétallisation de l'eau, où ledit procédé consiste à effectuer une micro-électrolyse de l'eau traitée laquelle donne à la fois des hydroxydes OH- et des oxydants tel que l'oxygène ou le chlore qui permettront directement ou indirectement la démétallisation. Selon une variante de la présente invention, le métal anodique des électrodes utilisées pour la démétallisation est le même que celui des électrodes utilisées pour la décarbonatation de l'eau faisant l'objet du brevet français n° 96 00714, le procédé de démétallisation et celui de décarbonatation pouvant être réalisés simultanément ou individuellement. Selon une autre variante, les électrodes utilisées seront spécifiques à un procédé de démétallisation appliqué seul.More specifically, the present invention relates to a process for demetallization of water, wherein said method consists in carrying out a micro-electrolysis of the treated water which gives both hydroxides OH- and oxidants such as oxygen or chlorine which will directly or indirectly allow demetallization. According to a variant of the present invention, the anodic metal of the electrodes used for demetallization is the same as that of the electrodes used for the decarbonation of water which is the subject of French patent n ° 96 00714, the demetallization process and that decarbonation can be performed simultaneously or individually. According to another variant, the electrodes used will be specific to a demetallization process applied alone.
La présente invention concerne également les moyens mis en oeuvre pour réaliser la démétallisation souhaitée et sera mieux comprise à la lecture de la description qui va suivre, faite en regard des figures données à titre exemplatif et nullement limitatif parmi lesquelles :The present invention also relates to the means used to achieve the desired demetallization and will be better understood on reading the description which follows, made with reference to the figures given by way of example and in no way limiting, among which:
- la figure 1 est un schéma représentant un dispositif selon une variante d'exécution où s'effectuent à la fois une démétallisation et une décarbonatation de l'eau à traiter.- Figure 1 is a diagram showing a device according to an alternative embodiment where both demetallization and decarbonation of the water to be treated are carried out.
- la figure 2 est un schéma représentant un dispositif selon une autre variante d'exécution où s'effectuent à la fois une démétallisation et une décarbonatation de l'eau à traiter. - la figure 3 est un schéma représentant un dispositif selon une troisième variante d'exécution où s'effectue seulement une démétallisation de l'eau à traiter.- Figure 2 is a diagram showing a device according to another alternative embodiment where both demetallization and decarbonation of the water to be treated are carried out. - Figure 3 is a diagram showing a device according to a third alternative embodiment where only demetallization of the water to be treated.
Selon une variante d'exécution de la présente invention, la démétallisation de l'eau se fait en même temps que sa décarbonatation. Dans ce cas le dispositif utilisé pourra consister en celui du procédé de décarbonatation faisant l'objet du brevet français n° 96 00714 ; ainsi ce dispositif représenté à la figure 1 pourra comprendre un réacteur (1) de forme cylindrique ou parallélépipèdique, la ou les cathodes étant constituées par la paroi latérale formant le réacteur et des parois intermédiaires, la ou les anodes étant disposées parallèlement à l'axe longitudinal dudit cylindre ou dudit parallélépipède. Selon cette variante, ledit axe longitudinal sera disposé verticalement, l'eau à traiter arrivant en partie inférieure (2) du réacteur, l'eau traitée étant récupérée dans la partie supérieure (3) dudit réacteur, le carbonate de calcium et l'oxyde de fer étant récupérés à la base (4) de ce réacteur (les électrodes à l'intérieur du réacteur ne sont pas représentées dans cette figure). Toujours selon cette variante, la ou les anodes seront filiformes ou sous forme de plaque(s) ; la, ou l'une des anodes pourra d'ailleurs constituer l'axe longitudinal dudit réacteur. Les autres caractéristiques du dispositif, ainsi que les valeurs électriques (ampérage, tension, fréquence) et les paramètres de circulation de l'eau (vitesse, sens) pourront reprendre celles décrites dans le brevet précité ; préférentiellement les différentes plages de ces valeurs seront appliquées en combinaison.According to an alternative embodiment of the present invention, the demetallization of water takes place at the same time as its decarbonation. In this case the device used may consist of that of the decarbonation process which is the subject of French patent n ° 96 00714; thus this device shown in Figure 1 may include a reactor (1) of cylindrical or parallelepiped shape, the cathode (s) being formed by the side wall forming the reactor and intermediate walls, the anode (s) being arranged parallel to the axis longitudinal of said cylinder or said parallelepiped. According to this variant, said longitudinal axis will be arranged vertically, the water to be treated arriving in the lower part (2) of the reactor, the treated water being recovered in the upper part (3) of said reactor, the calcium carbonate and the oxide of iron being recovered at the base (4) of this reactor (the electrodes inside the reactor are not shown in this figure). Still according to this variant, the anode or anodes will be filiform or in the form of plate (s); the, or one of the anodes may also constitute the longitudinal axis of said reactor. The other characteristics of the device, as well as the electrical values (amperage, voltage, frequency) and the water circulation parameters (speed, direction) may be those described in the aforementioned patent; preferably the different ranges of these values will be applied in combination.
Dans ces conditions de procédé simultané de démétallisation et de décarbonatation, la demanderesse a pu recueillir au fond du réacteur un carbonate de calcium ocré (l'oxyde de fer ayant précipité en même temps que le carbonate de calcium normalement blanc).Under these conditions of simultaneous demetallization and decarbonation process, the applicant was able to collect from the bottom of the reactor an ocher calcium carbonate (the iron oxide having precipitated at the same time as the normally white calcium carbonate).
Le carbonate de calcium ocré est la résultante de la présente invention dans l'application simultanée de la démétallisation et de la décarbonatation, qui permet, grâce à l'énergie électrique de créer les différentes voies de précipitation des ions « fer » contenus dans l'eau à déferriser sous forme de précipités « carbonés » ou de précipités « oxydés ».Ocre calcium carbonate is the result of the present invention in the simultaneous application of demetallization and decarbonation, which allows, thanks to electrical energy to create the different precipitation paths of the "iron" ions contained in the water to be ironed in the form of "carbon" or "oxidized" precipitates.
• les précipités « carbonés » ont l'origine suivante : en présence de carbonate[HCO3-], de dioxyde de carbone [CO2], selon le pH de l'eau à traiter et son évolution au cours des réactions, une partie de la précipitation observée concerne des carbonates de fer [FeCO3] et /ou des « fers carboniques » [FeCO2] (sidérite). Cette précipitation conjointe avec le carbonate de calcium [CaCO3] organise la coloration ocrée des cristaux de carbonate de calcium.• “carbonaceous” precipitates have the following origin: in the presence of carbonate [HCO3-], of carbon dioxide [CO2], depending on the pH of the water to be treated and its evolution during the reactions, part of the precipitation observed concerns iron carbonates [FeCO3] and / or “carbonic irons” [FeCO2] (siderite). This precipitation together with calcium carbonate [CaCO3] organizes the ocher coloration of the calcium carbonate crystals.
• la voie des précipités « oxydés » consiste en des précipités issus principalement de l'oxydation par l'oxygène [O2] naissant et/ou le chlore [C12]induit par l'électro-chloration des ions Cl- présents dans l'eau, lesquels sont adsorbés sur le média filtrant constitué par le carbonate de calcium issu de la décarbonatation précitée et contribue à la coloration en masse des cristaux.• the “oxidized” precipitate pathway consists of precipitates mainly resulting from oxidation by nascent oxygen [O2] and / or chlorine [C12] induced by the electro-chlorination of Cl- ions present in water , which are adsorbed on the filtering medium consisting of calcium carbonate from the above-mentioned decarbonation and contributes to the mass coloration of the crystals.
Dans le cas des eaux destinées à la consommation humaine la teneur en fer est statistiquement inférieure à 1% de la teneur en [CaCO3]. La demanderesse a également pu montrer qu'un dispositif non plus de type vertical, mais de type latéral avec les électrodes placées en chicanes donnait également de bons résultats, les mêmes caractéristiques électriques (15μA - 20 A/m ou m2 d'électrodes ;In the case of water intended for human consumption the iron content is statistically less than 1% of the [CaCO3] content. The Applicant has also been able to show that a device, no longer of the vertical type, but of the lateral type with the electrodes placed in baffles, also gave good results, the same electrical characteristics (15 μA - 20 A / m or m 2 of electrodes;
20μN - 48 N ; 0 - 1 GHz) et paramètres de circulation de l'eau au sein du réacteur20μN - 48 N; 0 - 1 GHz) and water circulation parameters within the reactor
(0-10 cm/s) pouvant être repris ; il est apparu à la demanderesse que l'ampérage pouvait avantageusement augmenter pour atteindre 200 A/m ou m2 d'électrodes. Dans cette variante illustrée à la figure 2, le réacteur (5) présente un axe longitudinal horizontal, les électrodes étant constituées de plaques (6) disposées en chicane ; l'arrivée d'eau se fait à une extrémité (7) et ressort, après traitement, à l'autre extrémité (8) du réacteur.(0-10 cm / s) can be resumed; it appeared to the applicant that the amperage could advantageously increase to reach 200 A / m or m 2 of electrodes. In this variant illustrated in FIG. 2, the reactor (5) has a horizontal longitudinal axis, the electrodes being made up of plates (6) arranged in a baffle; the water inlet takes place at one end (7) and leaves, after treatment, at the other end (8) of the reactor.
Dans le cas d'un procédé visant seulement à la démétallisation de l'eau, la demanderesse a trouvé qu'un autre dispositif pouvait valablement être utilisé, à savoir un dispositif de type transversal où les électrodes seraient préférentiellement constituées d'un matériau ajouré, notamment sous forme de grilles ; dans cette variante d'exécution, la vitesse de l'eau à traiter pourra atteindre 20 cm/s. C'est ce qui est illustré à la figure 3 où le réacteur (9) est doté d'électrodes (10), sous forme de plaques ajourées ou de grilles, l'eau à traiter arrivant en une extrémité (11) du réacteur et ressortant, après démétallisation en l' extrémité opposée (12), la circulation de l'eau se faisant donc transversalement par rapport aux électrodes (10). Pour des raisons de clarté, le dispositif, classique par ailleurs de récupération des précipités métalliques ou de carbonate de calcium ne sont pas représentés dans les figures 2 et 3. Il est également apparu avantageux de disposer d'un élément filtrant, classique ou membranaire à la suite du dispositif ; outre cet élément filtrant, le carbonate de calcium peut constituer un élément filtrant supplémentaire lorsque le procédé permet simultanément la démétallisation et la décarbonatation.In the case of a process aimed solely at the demetallization of water, the Applicant has found that another device could validly be used, namely a device of transverse type where the electrodes would preferably be made of an openwork material, especially in the form of grids; in this variant, the speed of the water to be treated can reach 20 cm / s. This is illustrated in FIG. 3 where the reactor (9) is provided with electrodes (10), in the form of perforated plates or grids, the water to be treated arriving at one end (11) of the reactor and coming out, after demetallization at the opposite end (12), the circulation of the water therefore takes place transversely with respect to the electrodes (10). For reasons of clarity, the device, which is also conventional for recovering metallic precipitates or calcium carbonate, is not shown in FIGS. 2 and 3. It also appeared advantageous to have a filtering element, conventional or membrane with the rest of the device; in addition to this filter element, calcium carbonate can constitute an additional filter element when the process simultaneously allows demetallization and decarbonation.
La demanderesse ne s'est pas limitée à la démétallisation de l'eau où le métal est le fer, c'est à dire à sa déferrisation. Selon la présente invention, des résultats avantageux peuvent en effet être obtenus pour d'autres métaux ; il en va ainsi du calcium et du magnésium (alcalino-terreux), de l'arsenic (métalloïde), du manganèse, du nickel, du zinc, du chrome, du cuivre et du plomb. Des études plus poussées ont été menées par la demanderesse concernant trois des métaux offrant le plus d'inconvénients, à savoir le fer, l'arsenic et le manganèse ; les résultats ci-dessous montrent bien l'intérêt du procédé utilisé par la demanderesse.The applicant has not limited itself to the demetallization of water where the metal is iron, that is to say its iron removal. According to the present invention, advantageous results can indeed be obtained for other metals; this is the case for calcium and magnesium (alkaline earth), arsenic (metalloid), manganese, nickel, zinc, chromium, copper and lead. Further studies have been carried out by the applicant concerning three of the metals with the most disadvantages, namely iron, arsenic and manganese; the results below clearly show the advantage of the process used by the applicant.
Métal Norme européenne Concentration obtenue grâce au procédé selon l'invention Fer 200 μg/1 < 30 μgMetal European standard Concentration obtained using the process according to the invention Iron 200 μg / 1 <30 μg
Manganèse 50 μg/1 < 30 μgManganese 50 μg / 1 <30 μg
Arsenic 10 μg/1 < 2 μgArsenic 10 μg / 1 <2 μg
On notera en particulier le résultat particulièrement intéressant concernant le fer, le procédé de déferrisation selon l'invention permettant d'obtenir un taux très nettement inférieur à la norme européenne de 200 μg/1 pour laquelle l'eau peut conserver cependant un goût désagréable ainsi qu'une légère coloration ocrée (pour mémoire une eau est dite « confortable » si la teneur en fer est inférieure ou égale à 100 μg/1, ce qui reste très supérieur au taux obtenu par la demanderesse). Note in particular the particularly interesting result concerning iron, the iron removal process according to the invention making it possible to obtain a rate very much lower than the European standard of 200 μg / 1 for which the water can however retain an unpleasant taste as well only a slight ocher coloration (for the record, water is said to be “comfortable” if the iron content is less than or equal to 100 μg / 1, which remains much higher than the rate obtained by the applicant).

Claims

REVENDICATIONS
1) Procédé permettant de réduire la concentration en ions métalliques contenus dans l'eau notamment destinée à la consommation humaine, caractérisée en ce qu'il consiste à effectuer une micro-électrolyse de l'eau constituant l'électrolyte, les constantes électriques étant choisies dans les fourchettes suivantes : • 15 μ A - 200 A/m ou m2 d' électrodes pour P ampérage,1) Method for reducing the concentration of metal ions contained in water especially intended for human consumption, characterized in that it consists in carrying out a micro-electrolysis of the water constituting the electrolyte, the electrical constants being chosen in the following ranges: • 15 μ A - 200 A / m or m 2 of electrodes for P amperage,
• 20 μN - 48 V pour la tension• 20 μN - 48 V for voltage
• 0 - 1 GHz pour la fréquence• 0 - 1 GHz for frequency
2) Procédé selon la revendication 1 caractérisé en ce que la vitesse du courant d'eau à traiter est comprise entre 0 et 20 cm/s au sein du réacteur. 3) Procédé selon l'une des revendications 1 ou 2 caractérisé en ce que la démétallisation de Peau est menée simultanément à sa décarbonatation par déshydratation des germes de carbonate de calcium.2) Method according to claim 1 characterized in that the speed of the water stream to be treated is between 0 and 20 cm / s within the reactor. 3) Method according to one of claims 1 or 2 characterized in that the demetallization of water is carried out simultaneously with its decarbonation by dehydration of the calcium carbonate seeds.
4) Procédé selon la revendication 3 caractérisé en ce que la vitesse du courant d'eau à traiter est comprise entre 0 et 10 cm/s au sein du réacteur. 5) Dispositif pour la mise en oeuvre du procédé selon l'une des revendications 1 ou 2 caractérisé en ce que les électrodes utilisées se présentent sous forme d'un métal ajouré, la circulation de l'eau se faisant alors transversalement par rapport aux électrodes.4) Method according to claim 3 characterized in that the speed of the water stream to be treated is between 0 and 10 cm / s within the reactor. 5) Device for implementing the method according to one of claims 1 or 2 characterized in that the electrodes used are in the form of an openwork metal, the circulation of water then taking place transversely to the electrodes .
6) Dispositif selon la revendication 5 caractérisé en ce que les électrodes se présentent sous forme de grilles. 7) Dispositif pour la mise en œuvre du procédé selon l'une des revendications 3 ou 4, caractérisé en ce que le réacteur est de forme cylindrique ou parallélépipédique, la ou les anodes étant disposées parallèlement à l'axe longitudinal dudit cylindre ou dudit parallélépipède, ledit axe étant disposé verticalement.6) Device according to claim 5 characterized in that the electrodes are in the form of grids. 7) Device for implementing the method according to one of claims 3 or 4, characterized in that the reactor is of cylindrical or parallelepiped shape, the anode or anodes being arranged parallel to the longitudinal axis of said cylinder or said parallelepiped , said axis being arranged vertically.
8) Dispositif selon l'une quelconque des revendications 5 à 7, caractérisé en ce qu'il est suivi d'un élément filtrant classique ou membranaire.8) Device according to any one of claims 5 to 7, characterized in that it is followed by a conventional filter element or membrane.
9) Dispositif selon l'une des revendications 7 ou 8 caractérisé en ce que la ou les anodes sont filiformes.9) Device according to one of claims 7 or 8 characterized in that the anode or anodes are filiform.
10) Dispositif selon l'une des revendications 7 ou 8 caractérisé en ce que la ou les anodes sont sous forme de plaque(s). 11) Dispositif pour la mise en œuvre du procédé selon l'une des revendications 3 ou 4 caractérisé en ce que les électrodes se présentent sous forme de plaques disposées en chicanes, l'entrée et la sortie de l'eau se faisant latéralement, l'axe du dispositif se présentant alors horizontalement. 10) Device according to one of claims 7 or 8 characterized in that the anode or anodes are in the form of plate (s). 11) Device for implementing the method according to one of claims 3 or 4 characterized in that the electrodes are in the form of plates arranged in baffles, the inlet and outlet of the water being made laterally, l axis of the device then being presented horizontally.
EP20030712275 2002-01-29 2003-01-22 Method for treating water in order to reduce the metal ion concentration thereof Withdrawn EP1470082A2 (en)

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FR0201015 2002-01-29
FR0201015A FR2835248B1 (en) 2002-01-29 2002-01-29 PROCESS FOR TREATING WATER WITH A VIEW TO REDUCING ITS CONCENTRATION IN METAL IONS
PCT/FR2003/000205 WO2003064329A1 (en) 2002-01-29 2003-01-22 Method for treating water in order to reduce the metal ion concentration thereof

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CN102659220B (en) * 2012-05-07 2013-12-11 四川大学 Method for removing ferric phosphate film and ferrous phosphate passivating film from filler surface layer in iron-carbon microelectrolysis reactor
CN102659219B (en) * 2012-05-07 2013-08-21 四川大学 Method for removing ferrous sulfide passivating film from filler surface layer in iron-carbon microelectrolysis reactor
CN103241907B (en) * 2013-05-28 2014-04-02 无锡百奥源生态环保科技有限公司 Method and device for treating organic oil-containing wastewater
CN103395919B (en) * 2013-08-03 2015-04-01 大连交通大学 Equipment for pretreatment of high-concentration perfume wastewater and method
CN104556307B (en) * 2013-10-09 2016-05-04 中国石油化工股份有限公司 A kind of compound micro-electrolysis stuffing and preparation method thereof
CN104230102B (en) * 2014-09-05 2016-06-22 河海大学 A kind of Novel sewage advanced treating biological denitrification strengthened denitrification device
CN104193110A (en) * 2014-09-17 2014-12-10 安徽省绿巨人环境技术有限公司 Wastewater treatment device and method
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WO2003064329A8 (en) 2004-04-29
FR2835248B1 (en) 2004-10-22
FR2835248A1 (en) 2003-08-01
PL371604A1 (en) 2005-06-27

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