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)

Applications Claiming Priority (3)

Publications (1)

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ID=27619709

Family Applications (1)

Country Status (7)

Families Citing this family (11)

Family Cites Families (5)

• 2002
  • 2002-01-29 FR FR0201015A patent/FR2835248B1/fr not_active Expired - Fee Related
• 2003
  • 2003-01-22 EP EP20030712275 patent/EP1470082A2/de not_active Withdrawn
  • 2003-01-22 AU AU2003216956A patent/AU2003216956A1/en not_active Abandoned
  • 2003-01-22 PL PL03371604A patent/PL371604A1/xx not_active Application Discontinuation
  • 2003-01-22 WO PCT/FR2003/000205 patent/WO2003064329A1/fr not_active Ceased
• 2004
  • 2004-07-29 TN TNP2004000143A patent/TNSN04143A1/fr unknown
  • 2004-08-04 MA MA27810A patent/MA26404A1/fr unknown

Non-Patent Citations (1)

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