CA2423213A1 - Combinined electroosmosis and electrocoagulation process - Google Patents

Abstract

Process for treating sludge and / or fluids in order to reach an advanced level of purification comprising two sequences. The first sequence implements an electro-osmosis (SEO) process and is characterized in that: (a) sludge and / or fluids are treated by the combined action of electro-osmosis with faction of the pressure and / or faction of a vibratory system (such as ultrasound or electro-acoustic) in a reactor. Step (a) implements the drainage of at least two effluents of different type. The first effluent comprises at least one pollutant, is generated at the cathode and is of basic pH, preferably between 10 and 12, more preferably still around 11. The second effluent comprises at least one pollutant, is generated at the anode, and is of an acidic pH, preferably between 4 and 6 more preferably still around 5. The second sequence implements an electrocoagulation process (SEC) is characterized in that: (b) treating at least one effluent obtained in the first sequence by passing an electric current through this effluent so as to electrocoagulate at least one pollutant which it contains; and (c) separating the electrocoagulated pollutant from at least one treated effluent. The order in which the sequences are carried out can be reversed, if the sequence is first carried out (SEC), at this time, the effluent collected during the implementation of the sequence (SEC) is used in place of sludge and / or fluids in the sequence (SEO).

Description

COMBINED ELECTRO-OSMOSIS PROCESS AND
electrocoagulation FIELD OF THE INVENTION
The present invention relates to the field of electrochemistry applied to the treatment of sludge and wastewater.
In particular, (the invention relates to a method allowing the dewatering, compression and / or depollution of sludge by the action combined electro-osmosis and / or a vibratory system and / or pressure, then a treatment of wastewater obtained via electrocoagulation of pollutants contained in this wastewater. In some cases, the method allows the formation of a apatite from certain types of wastewater.
PRIOR ART
The treatment of clay soils has always been a problem the civil engineer by its low hydraulic permeability. The techniques of consolidation by loading and vertical drains require a lot of time of immobilization of the land in question and improvements in resistance mechanical properties of the soils are (around 50%.
The phenomenon of electro-osmosis, the transport of water from the pores in the capillaries, under (influence of an electrical potential has been observed for the first time almost 200 years ago. The electro-osmosis phenomenon is based on the causes a direct current electrical potential to cause movement of cation (positive ions), from the positive pole (anode) to the negative pole (cathode) and it trained by viscous action of water molecules. The application of an electrical potential at by means of electrodes implanted in a deposit of fine-grained soil (silty or clay) allows soil drainage, consolidation without overload.
Although known for a long time, electro-Osmotic clay has so far been applied very little. The main difficulty in applying this process is related to losses of potential at the anodes. These losses were attributed to the decrease in content water, in the vicinity of (anode, reduction of the conductivity of the pore water, presence of gases generated by electrolysis reactions and finally dissolution of anode material. These losses can also be due to poor contact physics of the anode with the material. The effective voltage gradient applied to soil can be a small fraction of that applied to the electrodes.
CASAGRANDE, in the 1930s, made applications on the land, by passing an electric current through the ground (materials porous, silts and clays), Skin circulates between two electrodes from the pole (+) towards the pole (-). This technique took the name of electro-osmosis. Electro-osmosis has been used in several applications in civil engineering. It has been used for: (a) increasing the bearing capacity of the piles; (b) reduction of friction negative in the piles; (c) stabilization of slopes; (d) consolidation soils.
During felectro-osmosis applications in the stabilization of embankment and soil consolidation, researchers when they sought to modify the behavior of the water, noted great losses of potentials neighborhood anodes (Wade, 1973; BJERRRUM and Co11., 1967; HANSB0,1970; LO et al., 1990); increases in resistances and reductions in u which are not not uniforms. Drainage rates decrease during treatment. The document Electroosmotically Enhanced Sludge Pressure Filtration published on pages 267 to 276, volume 71, number 3 Water Environnement Research describes a device implement electro-osmosis with a mobile electrode in order to improve the sludge filterability.
In the literature, it has been observed that the problem of consolidation electro-osmotic is linked to the loss of voltages at the anodes [WADE, 1973];
Bjerrum et al. [1967]; Hansbo [1970]; Lo et al. [1990]]. The loss of potential to the anode was attributed to the increase in electrical resistance after reduction of the water content [Casagrande [1983]; Johnson [1967]]. It is believed that the loss of voltage at the anodes is not due solely to the reduction in the content of water, but it is the combination of the following three parameters:
- physical ground-electrode contact;

-2-- presence of the gas produced by the electrolysis reaction; and - increase in electrical resistance by reductions in the content of water and of the conductivity of the pore water.
The application of an electric field can produce a variety of chemical reactions at the electrodes, the charge being transferred through the middle porous. The existence of a current in the medium implicitly requires the Faraday reactions at the limits of the electrodes. Gradient formation chemicals will depend on the extent of electrolysis and chemical reactions coupled between the medium to be treated and the electrolyte produced.
These effects include the electrolysis of water with development simultaneous pH gradients and electrolytic transfer of dissolution of the anode (oxidizable) producing metal ions or the cations of the electrolyte the anode to the cathode.
Chemical reactions can, in ion exchange or precipitation form new mineral phases in the porous mass between the electrodes.
All organic or inorganic sludge consists of a combination of a solid phase with a certain amount of liquid. The behavior of the liquid part is often wrongly considered to be the same than ordinary water. There are different physical forms of water in the sludge who play a decisive role in its extraction.
In this type of material Skin can appear in three states:
- incorporation;
- absorbed skin; and - Interstitial or free skin.
In addition to these three fundamental states, we can cite an intermediate state:
Capillary skin.
The water of constitution is part of the very molecule of the material.
It cannot be extracted from it without altering its composition chemical.
The adsorbed water, by the action of molecular forces, is found in a state

-3-special and does not respond to the classic laws of Free Skin: it cannot evaporate when subjected to a temperature of 100 oC and it presents a significantly higher viscosity.
There was therefore a need for the development of a process putting using electro-osmosis and allowing efficient treatment of sludge, retaining its effectiveness during treatment. In addition, it is necessary to treat the wastewater recovered during the treatment of this sludge.
Coagulation is one of the most important physical-chemicals used in water treatment. This process is notably in use to cause destabilization and aggregation of small particles into more large particles. Water contaminants like ions (heavy metals) and colloids (organic and inorganic) are mainly retained in solution by electrical charges. Schultze, in 1882, showed that the systems colloids could be destabilized by the addition of charged ions opposite to that of the colloid (Benefield et al., 1982). Colloids as well destabilized can be aggregated and subsequently removed by sedimentation and / or filtration.
Coagulation can be done by chemical or electrical means.
Chemical coagulation is less used these days because of the costs high associated with chemical treatments. The high costs are explained by (use chemicals needed for coagulation and also by the large volume of sludge and hazardous heavy metal waste such as hydroxides of metals which are thus generated. Chemical coagulation processes comprising coagulants such as alum, lime and / or polymers have been used over the past few decades.
The principle of electrocoagulation has been patented for the first time in 1906 by AE Dietrich and was used to treat bilge water from boats.
Over time, a number of attempts have been made to improve and commercialize the technology with varying degrees of success. different variety anodes and cathodes having various geometries were used, including plates, rounds, rods, tubes ... etc.

-4-Electrocoagulation is a principle-based process scientists in which water contaminants are subjected to strong fields electric, thus causing oxidation and reduction reactions. This process is capable of removing more than 99%. hundred of a few heavy metal cations and also appears capable of electrocuting microorganisms in water. The process can precipitate charged colloids and remove quantities important other ions, colloids and emulsions.
Although the mechanism of electrocoagulation is very similar to that of chemical coagulation, the cationic species responsible for the neutralization of the surface of the charges and the characteristics of the waves electrocoagulated differ in each of these processes. An electrocoated stream tends to contain less bound water, it is more resistant to shearing and more easily filterable. Electrocoagulation can often neutralize ions and particle charges, allowing contaminants to precipitate. It is so possible and reduce the contaminant content to lower concentrations at those attainable via chemical precipitation processes. At the same time, he is possible to replace and / or reduce the use of chemical agents expensive such as polymers or metallic salts.
Electrocoagulation is based on the principle of soluble anodes. he is to generate, by imposing a direct current between the iron electrodes, aluminum or any alloy, metal cations (Al3 + or Fe3 +) who will play the role of coagulants to allow destabilization by discharge of suspended particles and colloidal structures.
The formation of iron or aluminum hydroxides and the geometry peculiarities of electrocoagulation reactors cause flocculation. The flows thus formed can be eliminated by flotation.
The electrochemical process in addition to the coagulation phenomena-flocculation involves redox reactions at the electrodes oxidation at the anodes and reductions at the cathodes depending on the reactions presented below below. The following electrochemical reactions develop at electrodes:

Anode 2H20 - 4th 02 + 4H + (1) A1 Al3 + + 3 e (2}
Fe Fe3 + + 3rd (3) Cathode 2Hz0 + 2e H2 + 20H- (4) When two metal electrodes between which a potential difference immerse in a solution, the ions present are subject to the action of the electric field, the negative ions go towards (anode then that positive ions go to the cathode. The passage of current through the solution is thus due to the transport of electrical charges via anions and cations. The ions arriving at the electrodes discharge there and participate in of the reactions of which (together constitutes the phenomenon of electrolysis.
In addition, the streams of ions and charged particles created by the electric field increase the probability of collision between ions and particles of opposite sign which migrate in opposite directions. This action bring them together suspended matter in the form of a floc which is removed by micro bubbles produced at the electrodes.
During water treatment, electrolysis reactions to electrodes (3) and (4) make it possible to produce micro-bubbles of oxygen and hydrogen. These micro bubbles, finely divided will result in their upward movement the flocs thus formed.
For a current of intensity, I, constant, the weight P of electrolyte decomposed is proportional to (current intensity and duration, i.e.
say, at the total amount of electricity, Q, which has passed through the electrolyte. As example, for an aluminum anode, a (I) Faraday (96500 Coulombs) breaks down a gram equivalent, or 9 'of aluminum and 18 grams of iron.
Dissolution of metal ions from the anode increases considerably the roughness of the anodes. For this reason, (electrocautery does not cannot produce tiny, uniform bubbles. The dimensions of bubbles produced by electrocoagulation are generally greater than 100 ~, m. Of more, the roughness of the surface of (anode increases the adhesion strength of bubbles this which decreases the effectiveness of the treatment. It is generally believed that the more bubbles the smaller the separation efficiency of the flotation process big.
Electrocoagulation can also be used with inert electrodes based on titanium coated with iridium or platinum, we speak in this case electroflotation. The advantage of electroflottation is more to remove the particles that have aggregated but not separated during the process electrocoagulation.
Electrofotation with the use of smooth inert electrodes, standardizes and reduces the size of micro bubbles and minimizes the effects of their adhesion. Small bubbles allow better flotation of the particles suspended in the Skin. By cons, (absence of cations metal, necessary to neutralize electrical charges of pollutants, reduced effectiveness the depollution of these waters.
The application of an electric field can produce a variety of chemical reactions at the electrodes, the charge being transferred through the middle porous. The existence of a current in the medium implicitly requires the Faraday reactions at the limits of the electrodes. Gradient formation chemicals will depend on the extent of electrolysis and chemical reactions coupled between the medium to be treated and the electrolyte produced. These effects include the electrolysis of water with the simultaneous development of pH gradients and the electrolytic transfer of the dissolution of the (oxidizable) anode producing ions or the electrolyte cations from the anode to the cathode (Gray and Olsen, 1986). Chemical reactions can, in ion exchange or _7_ precipitation form new mineral phases in the porous mass between the electrodes (Titkov et al., 1961; Gray and Schlocker, 1969).
Coagulation is the destabilization of the suspension by discharging colloidal structures using a chemical reagent called a coagulant.
Wastewater electrocoagulation can also be applied to the formation of apatites having the chemical formula Calo (P04) 6X2 where X can be a ion Cl, F- or OH-. According to the counterion, we would have chloroapatite, fluoroapatite and hydroxyapatite, respectively. There is also a carbonate-apatite (X2 = CO3) but bromoapatite (X = Br) and iodoapatite (X = I) do not exist in the nature. These apatites constitute the most abundant phosphate mineral on earth and have a hexagonal crystal structure. There are two physical forms in nature: centimetric single crystals of magmatic origin (fluoroapatite) or in the form of crystallites of a few microns of sedimentary origin (hydroxyapatite, X = OH). There are synthetic hydroxyapatites marketed in powder form, such as that of the company BioRad.
The hydroxyapatite formation reactions have been widely studied and often imperfectly explained. Work in this area are more news. Salt Ca3 (P04) 2 is never the product of the reaction of precipitation. If the pH is neutral, alkaline or only slightly acidic, the precipitated phosphorus remains insoluble. These disparities are due to the mechanism of two-stage precipitation first involving acid phosphates of calcium. The doses of lime are directly dependent on the nature of the water to treat. We notice that, thermodynamically speaking, there is competition enter here precipitation of calcite and hydroxyapatite between pH 9 and pH 10.5.
Several research groups have previously used reagents chemicals to Treat wastewater and form hydroxyapatite. Gray (nineteen eighty one) reported the use of an acidic bauxite attack solution which contains mainly ferric sulfate and aluminum sulfate. Kuziemska (1980) a used in primary precipitation, an aqueous leach solution of ashes thermal power plant. The efficiency obtained is attributed to the presence _G_ simultaneous calcium, iron and aluminum. On the other hand, Doboly (1978) was able cause the phosphating of water by electrolytically generating ions aluminum. The efficiency of the latter process was found to be higher compared to the use of alum containing the same amount of aluminum.
This improvement is due to a greater reactivity of the Al3 + ions (aluminum incipient), than that of the hydrated aluminum complexes coming from the reagent chemical.
The main reactions to the electrodes have been described above by reactions (1) and (4).
The production of H + ions by electrolysis, causes a drop in pH
by reaction (1), undesirable. The neutralization of these H + products occurs made in presence of calcium according to the following reaction (5) 4H + + 2CaC03 ----, 2Ca2 ~ + H2C03. ( This neutralization promotes the diffusion of calcium ions in the middle.
The production of OH- ions makes the pH basic by reaction (3).
The latter is essential for achieving the desired pH. The presence of ions calcium, phosphorus and hydroxide ions allow the reaction (6) above below, relating to the formation of hydroxyapatite.
SCa2 + + 3HP042- + 40H '--r Case (OH) (P04) 3 (hydroxyapatite) + 3H20 (b) A first aspect of the invention relates to a treatment method sludge and / or fluids in order to reach an advanced level of purification comprising two sequences, the first sequence implementing an electro-osmosis process (SEO) is characterized in that:

a) sludge and / or fluids are treated by combined faction of electro-osmosis with faction of pressure and / or with the action of a system vibratory (such as ultrasound or electro-acoustic) in a reactor, step (a) using drainage of at least two different types of effluents, the first effluent comprising at least one pollutant is generated at the level of the cathode has a basic pH, preferably between 10 and 12, more preferably still around 11, and the second effluent comprising at least less pollutant is generated at the anode is of an acidic pH, understood preferably between 4 and 6 more preferably still around 5;
and the second sequence implementing a process of electrocoagulation (SEC) is characterized in that:
b) treating at least one effluent obtained in the first sequence by passing an electric current through this effluent from way to electrocoagulate at least one pollutant it contains; and c) separating the pollutant electrocoa.gulé from said at least one treated effluent.
The order in which the sequences are performed can be reversed, if first carry out the sequence (SEC), at that time, the effluent collected when implementation of the sequence (SEC) is used in place of sludge and / or fluid in the sequence (SEO).
A second aspect of the invention relates to a treatment method sludge and / or fluids in order to reach an advanced level of purification comprising two sequences, the first sequence implementing an electro-osmosis process (SEO) is characterized in that:
a) sludge and / or fluids are treated by the combined action of electro-osmosis with faction of pressure and / or with the action of a system vibratory (such as ultrasound or electro-acoustic) in a first reactor, (step (a) implementing the drainage of at least two effluents of the type different, the first effluent comprising at least one pollutant is generated at the level of the cathode has a basic pH, preferably between 10 and 12, more preferably still around 11; and the second effluent comprising at less pollutant is generated at the anode is of an acidic pH, understood preferably between 4 and 6 more preferably still around 5;
and the second sequence implementing a process of electrocoagulation (SEC) is characterized in that:
b) at least one effluent obtained is introduced into the first sequence in a second reactor fitted with electrodes, i.e. at least one cathode and at least one anode;
c) an electric current is passed through the chosen effluent to step (b) so as to electrocoagulate said at least one pollutant which it contains; and d) separating said electrocoagulated pollutant from said at least one effluent.
The order in which the sequences are performed can be reversed, if fon first performs the sequence (SEC), at that time, the effluent collected when implementation of the sequence (SEC) is used in place of sludge etlou fluid in the sequence (SEO).
A third aspect of the invention relates to a treatment method sludge and / or fluids in order to reach an advanced level of purification comprising two sequences, the first sequence implementing an electro-osmosis process (SEO) is characterized in that:
a) sludge and / or fluids are treated by combined faction of electro-osmosis with the action of pressure and / or with the action of a system vibratory (such as ultrasound or electro-acoustic) in a first reactor, (step (a) implementing the drainage of at least two effluents of the type different, the first effluent comprising at least one, pollutant is generated at the level of the cathode has a basic pH, preferably between 10 and 12, more preferably still around 11, and the second effluent comprising at least less pollutant is generated at the anode is of an acidic pH, understood preferably between 4 and 6 more preferably still around 5;
and the second sequence implementing a process of electrocoagulation (SEC) is characterized in that:
b) at least one effluent obtained is introduced into the first sequence and, where appropriate, an additive chosen from the group consisting of a ion source F-, ion source CI-, ion source B ~, source of ions I-, a source of C032 ~ ions and a mixture of said sources, in a second reactor provided with at least one cathode and at least one soluble anode comprising a source of Ca2 + ions, said at least one effluent comprising at least one orthophosphate; and c) an electric current is passed through said at least one effluent chosen in step (b) so as to cause diffusion of Ca2 + ions in said at least one effluent and thus form a precipitate consisting of an apatite or a mixture of apatites, the pH of said at least one effluent in step (c) being maintained at a value of around 8.9.
The order in which the sequences are performed can be reversed, if we first carry out the sequence (SEC), at that time, the effluent collected during of the implementation of the sequence (SEC) is used in place of sludge and / or fluid in the sequence (SEO).
A fourth aspect of the invention relates to a treatment method sludge and / or fluids in order to reach an advanced level of purification comprising two sequences, the first sequence implementing an electro-osmosis process (SEO) is characterized in that:
a) sludge and / or fluids are treated by the combined action of electro-osmosis with faction of pressure and / or with the action of a system vibratory (such as ultrasound or electro-acoustic) in a first reactor, said step (a) implementing the drainage of at least two effluents from type different, the first effluent comprising at least one pollutant is generated at level of the cathode has a basic pH, preferably between 10 and 12, more preferably still around 11; and the second effluent comprising at less pollutant is generated at the anode is of an acidic pH, understood preferably between 4 and 6, more preferably still around 5;
and the second sequence implementing a process of electrocoagulation (SEC) is characterized in that:
b) at least one effluent obtained is introduced into the first sequence and, if appropriate, an additive chosen from the group consisting of a source of ions F ~, a source of ions Cl-, a source of ions Br, a source of ions I-, a source of CO32 ~ ions and a mixture of said sources, in a second reactor provided with at least one cathode and at least one soluble anode comprising a source of Ca2 + ions, said at least one effluent comprising at least one orthophosphate; and c) an electric current is passed through said at least one effluent chosen in (step (b) so as to cause diffusion of Ca2 + ions in said at least one effluent and thus form a precipitate consisting of at least one apatite, the pH of said at least one effluent at (step (c) being maintained at a value about 8.9 The order in which the sequences are performed can be reversed, if we first carry out the sequence (SEC), at this point Here, the effluent collected when implementation of the sequence (SEC) is used in place of sludge and / or fluid in the sequence (SEO).
A fifth aspect of the invention relates to a combined method of treatment of sludge and / or fluids in order to reach an advanced level of purification and preparation of an apatite of formula:
Case (P04) 3X (I) or Calo (P04) 6Xa (II) or of a mixture of apatites of formula (I) or (II), formulas in which X
represents an ion chosen from the group consisting of F-, Cl-, Br, I-, OH-and CO3a-, provided that when fapatite meets formula (I), X cannot represent CO32-, comprising two sequences, the first sequence implementing an electro-osmosis process (SEO) is characterized in that:
a) the sludge and / or the fluids are treated by the combined action of electro-osmosis with the action of pressure and / or with the action of a system vibratory (such as ultrasound or electro-acoustic) in a first reactor, said step (a) implementing the drainage of at least two effluents from type different, the first effluent comprising at least one pollutant is generated at level of the cathode has a basic pH, preferably between 10 and 12, more preferably still around 11, and the second effluent comprising at least less pollutant is generated at the anode is of an acidic pH, understood preferably between 4 and 6 more preferably still around S;
and the second sequence implementing a process 1 S of electrocoagulation (SEC) is characterized in that:
b) at least one effluent obtained is introduced into the first sequence and, where appropriate, an additive chosen from the group consisting of a source of F- ions, source of Cl- ions, source of Br ions, source of ions I-, a source of CO32- ions and a mixture of said sources, in a second reactor provided with at least one cathode and at least one soluble anode comprising a source of Ca2 + ions, said at least one effluent comprising at least one orthophosphate; and c) an electric current is passed through said at least one effluent chosen in step (b) so as to cause a diffusion of Ca2 + ions in said 2S at least one effluent and thus form a precipitate consisting of an apatite of formula (I) or (II), or of a mixture of apatites of formula (I) or (II), the pH of said effluent to step (c) being maintained at a value of approximately 8.9.
The order in which the sequences are performed can be reversed, if fon first performs the sequence (SEC), at that time, the effluent collected when implementation of the sequence (SEC) is used in place of sludge etlou fluid in the sequence (SEO).
It was surprisingly found that the movement of the electrodes by inserting mechanical pressure, allows better contact on the totality cross sections of the electrodes and on the material. The reduction in volume of the sample represented by the reduction in the length of the material allows increasing the voltage gradient for a voltage kept constant Between the electrodes for the duration of the treatment.
It was also surprisingly found that in the case of agrifood sludge, the water content is very high which leaves assume the presence of a fluid at the start of treatment. With fixed electrodes, we have found that drainage or reduction of water leads to reduction of area of contact between the material and the electrode. The extracted water flow decreases, in considering the coefficient of electro-osmotic permeability ke constant, according to relation Qe = ke A.ie, where i ~ represents the electric gradient, At the section transversal and Qe the flow. Which, according to the previous mathematical relation, results in a decrease in flow.
BR ~ VE DESCRIPTION OF THE FIGURES
Figure 1 shows an electro-osmosis cell according to a mode of realization of the present invention. In the cell that is more particularly suitable for discontinuous sludge treatment:
1- Represent a cell in Plexiglas 2- Represents an extension of the cell to house the anode 3- A mobile anode 4- A pneumatic piston connected to the anode

5- A fixed cathode

6- Support

7- Electrical contacts

8- Drainage and gas evacuation orifices

9- Voltages measurement pads Figure 2 represents a batch cell according to another mode of realization of the invention;
Figure 3 shows an internal front view and a bitter view S of a batch cell according to the invention and according to the cutting plane (1.2A) -(1.2A) parallel to the walls of the facing electrodes;
Figure 4 shows a front view of an anode according to the invention and the corresponding side sections;
Figure 5 shows the lower part of a batch cell according to the invention provided with perforations;
Figure 6 shows on the left a continuous system according to the invention and the corresponding right part in internal section;
Figure 7 shows a top view in section showing the sludge removal system after treatment;
Figure 8 is a schematic representation of an apparatus for wastewater treatment, according to a preferred embodiment of the invention;
Figure 9 is a perspective view of the reactor used in The device illustrated in Figure 8, including the cover and a side wall vertical have been removed for illustration purposes;
Figure 10 is a perspective view of a variant of the reactor used in the device illustrated in Figure 8, the cover and a wall vertical lateral have been removed for illustration purposes; and Figure 11 is a perspective view of the sludge collector used in the device illustrated in Figure 8.
DETAILED DESCRIPTION OF THE INVENTION
The process of dehydration, compacting and depollution of sludge by combined action of pressure and electro-osmosis, present invention is a mechanical-electro-osmotic process: This mechanical-electro-osmotic, in horizontal or vertical position, consists of a container, of the electrodes, a frame, a pressure system and a power supply electric.

The mud is inserted into the container between the two electrodes. A
pressure system allows the application of pressure to allow a better permanent contact of the entire surface of the electrodes on the mud. Cables and the tubes are connected to the holes and to the pads provided for this purpose to the two electrodes.
The cell is designed to contain the mud. The cross section of the latter can be rectangular or circular. The container will be installed in horizontal or vertical position.
Sludge, with low dryness, is introduced into the container by a pumping system through an opening provided in the upper part, provided with a valve to prevent the return of sludge. The container is extended to one of his ends to accommodate the mobile electrode. In the extension of the container of the reservations (holes) are provided for the passage of cables and piping.
The system will be fixed on a support. The latter will allow fixing, the rigidity of the system. In addition it will also allow the movement of the containing for emptying the sludge after treatment. The container must be straight, to allow uniform movement; constant friction between the interface internal anode-wall. The system will be sealed by rubber provided for this purpose.
At each end of the container, an electrode of the same shape as the cross section of the container. The electrode is composed of two parts:
- the first part preferably consists of a metal plate perforated and in contact with sludge; and - the second part is preferably made of a non-conductive material such as plastic with a tank on the back of the plate metallic.
This tank will be provided with two (2) orifices, one provided for drainage, the other for gases produced by electrolysis reactions.
The metal plate is connected by a metal stud to a cable which is connected to the power source. It is imperative to have seals resistant and flexible sealants to minimize friction on the walls of container.
The DC generator is installed in the system to produce the power required for operation.
Figure 8 shows schematically an apparatus for wastewater treatment comprising a supply tank 10 intended for receive the water to be treated, a 12 or 12 'reactor used to treat the waste water and one sludge collector 14 for recovering the sludge formed during the treatment of the skin worn. The supply tank 10 is connected to a pump 16 via a conduit 18. The pump 16 is connected to the inlet 20 of the reactor 12 or 12 ′ by a conduit 22.
Wastewater contained in the tank 10 can be an effluent generated or collected during of treatment of a sludge via an electro-osmosis process as described in the this request. In addition, the sludge formed and recovered by the collector 14 during the wastewater treatment can also be treated via the electro-osmosis described in this application.
As illustrated in FIG. 9, the reactor 12 comprises a carcass 24, a bottom 26, a removable cover (not illustrated) and two blocks of electrodes 28 and 30, arranged inside the carcass 24. Each of these electrode blocks is mounted on a support 32. The supports 32 respectively define under the blocks 28 and 30, spaces 34 and 36 allowing the passage of the skin to be treated. The block electrode 28 includes electrodes 38 arranged in parallel and the electrodes are spaced in order to define between them spaces 40 allowing the passage of Skin. Analogously; the block 30 includes electrodes 42 arranged way parallel and the electrodes 42 are spaced to define between them spaces 44 allowing the passage of Skin. The electrode blocks 28 and 30 can include or not the same number of electrodes and the electrodes 38 and 42 can be made of the same material or not. The nature of the material (s) component the electrodes 38 and 42 may vary according to the composition of the water to be treated and according to contaminants contained therein. The electrode blocks 28 and 30 are separated by two walls 45 and 46 respectively having an upper slot 47 and a lower slot 48 and defining between them a space 49 allowing water from laminar flow. The upper slot 47 is arranged at a height such preventing the mud from entering the space 49. A wall 50 is arranged in upstream of the block of electrodes 28, the wall 50 defining a lower slot 52 intended to receive Skin to be treated. A wall 53 defining a slot higher 55 is arranged downstream of the electrode block 30 and a wall 54 defining a slot lower 56 is arranged downstream of the wall 53. The walls 53 and 54 define between them a space 57 allowing the water to flow in a laminar manner before enter a retaining compartment 68 disposed downstream of the wall 54 and intended to receive the treated water.
The Z 2 reactor also includes a feed compartment 58 disposed upstream of the wall 50. The compartment 58 is provided with walls 60 and 62 defining respectively upper slots 64 and 66 which allow (laminar flow of water. On the other hand, the compartment of detention 68 comprises a wall 70 defining an upper slot 72 and a sub-compartment 74 used to collect the water intended to be discharged from the reactor via an outlet 76 and through a conduit 78.
As illustrated in Figure 10, the reactor 12 'includes a carcass 24, a bottom 26, a removable cover (not shown) and a block of electrodes disposed at (inside the carcass 24: The electrode block 28 is mounted on a support 32. Support 32 defined under the electrode block 28 a space 34 allowing the passage of the water to be treated. The electrode block 28 includes electrodes 38 arranged in parallel and the electrodes 38 are spaced in order to define between them spaces 40 allowing the passage of water. Nature from where materials constituting the electrodes may vary depending on the composition of water to treat and according to the contaminants contained in the latter. A wall 50 East disposed upstream of the electrode block 28, the wall 50 defining a slot lower 52 intended to receive the water to be treated. A wall 53 defining a slit upper 55 is arranged downstream of the electrode block 28 and a wall 54 defining a lower slot 56 is arranged downstream of the wall 53. The walls 53 and 54 define between them a space 57 allowing the water to flow in a way laminar before entering a holding compartment 68 disposed downstream of the wall 54 and intended to receive the treated water.
The reactor 12 'also includes a feed compartment 58 disposed upstream of the wall 50. The compartment 58 is provided with walls 60 and 62 defining respectively upper slots 64 and 66 which allow the flow of water in a laminar fashion. On the other hand, the compartment of detention 68 comprises a wall 70 defining an upper slot 72 and a sub-compartment 74 used to collect the feaù intended to be evacuated from the reactor 12 ' via an outlet 76 and through a conduit 78.
As illustrated in Figure 11, the sludge collector 14 includes a recovery tank 80 connected to a vacuum cleaner 82 via a pipe 84. The tank 80 comprises a carcass 86 provided with an inlet 88, an outlet lower 90 and an upper orifice 92 connected to the conduit 84. A wall 94 provided with perforations 96 is arranged at (inside the carcass 86. The wall 94 define a upper chamber 98 and a lower chamber 100. Entrance 88 is connected to a conduit 102 through which the formed mud is sucked. The perforations 96 of the wall 94 allow mud to pass from the upper chamber 98 to the chamber lower 100.
When the apparatus of FIG. 8 is provided with the reactor 12, (water to to be treated is homogenized in the reservoir 10 by means of homogenization (no illustrated), then it is routed through pump 16 in the conduits 18 and 22 before reaching inlet 20 of reactor 12. The water to be treated arrives then in the compartment 58 of reactor 12 where it flows in a laminar fashion along the walls 60 and 62, and through the upper slots 64 and 66. Then, the water flows from laminar between the walls 50 and 62 before passing through the slot lower 52 and circulate in (space 34 under the electrode block 28 resting on the support 3f. The water then rises laminarly between the electrodes 38, in the spaces 40, in order to be treated and a mud is thus formed. Water as well treated a first time, go through the slot 47 in order to reach the space 49 defined between the walls 45 and 46 where it flows in a laminar fashion before passing through slot lower 48. Then, the water circulates in the space 36 under the block of electrodes resting on the other support 32. The water then rises laminarly between the electrodes 42, in spaces 44, in order to be treated a second time and another mud is thus formed. Following this second treatment, the treated water through the slot 55 in order to reach the space 57 defined between the walls 53 and 54 where she laminar flow before passing through the bottom slot 56 and join the holding compartment 68.
The treated water then runs along the wall 70 before passing through the upper slot 72 and reach the sub-compartment 74. Finally, the water treated is evacuated from the reactor 12 by the outlet 76 then by the conduit 78.
When the apparatus of Figure 8 is equipped with the reactor 12 ', the water circulates in the reactor 12 ′, in a similar manner to the above mentioned for reactor 12.
As shown in Figure 11, the mud formed above the blocks of electrodes 28 and 30 of reactor 12, or that formed above the block electrode 28 of the reactor 12 ′, is recovered by the sludge collector 14. The sludge is sucked through the conduit 102 enters the upper chamber 98 of the reservoir 80 via the inlet 88. This suction is generated by the vacuum cleaner 82 which is connected to the tank 80 by the conduit 84. Then, the mud passes through the perforations 96 of the wall 94 in order to reach the lower chamber 100 where it is finally evacuated via the lower outlet 90.
EXAMPLES
The following examples are given for illustrative purposes only and do not can in no way be interpreted as constituting any limitation of the subject of the present invention.
Example 1- Food sludge Procedure - material Carrying out the test requires carrying out the operations following:

- filling the cell with the sludge to be treated;
- the complete mounting of the cell on the device; and - (installation of electrodes and connections.
First place the cell shown in horizontal position on Figure 1, in the vertical position and the cover Z is opened consisting of removable extension of the cell in which the sludge is treated.
Elecirode 3 is also disassembled and cell 1 completely filled with the mud to treat.
Once (electrode 3 positioned on the upper surface of the mud, the cover 2 which is an integral part of the cell is closed and the cell 1 repositioned in horizontal position. The cell is secured to the ground help supports 6, using threaded rods passing through the feet of the supports 6.
The electrodes are energized by connecting the contacts 7 with the power source (not shown).
The device is then put under pressure using the piston 4 which is secured to the electrode 3 by means of the rod 10 and the pressure is then gradually increased. The evacuation of liquid effluents is carried out.
at level of the drainage orifices 8.and that of the gaseous effluents is produced at level 8 'holes. When the emission of effluents decreases significantly, we stopped treatment, we finally measure the dryness of the treated sludge, this value is significant of the waste water content.
Performing the test Agrifood sludge obtained in the processing industry meat is processed. It is a mud resulting from several treatments physico-chemical type DAF, in particular with ferric sulfate, on a mixture of meats consisting essentially of pork. This mud has summer filtered to remove all meat residue exceeding 2 mm. This mud East characterized by a resistivity of 238 S2.cm.

The sludge is placed in a cell in a humidity-controlled chamber and this, in order to reduce the drying of sludge due to the temperature of the piece that could be between 20 and 25 ° C.
The mud is installed in the cell in five (5) 3 cm layers each with a low compaction carried out with a pestle of approximately 200 grams to reduce voids and to ensure uniformity of all layers.
The anode and the piston are installed and the assembly is assembled to the help from four (4) threaded rods. The electrical connections as well as the pipes are installed.
The mud sample is subjected to an average pressure of the order 13 kPa. This pressure, at the start of treatment, is of the order of 2 to 3 kPa and she is increased to SO kPa. The water contents of the initial sludge are measured during the installation of each layer:
After pressurization, the sludge sample is put under electric tension. Thus, an initial voltage gradient of the order of 0.5 Volts / cm is applied which leads to a total voltage applied between the electrodes 8.5 Volts. This voltage was kept constant throughout the treatment. A
current initial of 130 mA was measured just at the output at pad number 7.
After a few minutes of treatment, i.e. after the mud has been subjected to pressure as well as voltage, there is a flow of liquid through the two electrodes, i.e. both at anode than at the cathode. It should be noted that the electrodes were, at the prior, perforated:
The effluents collected are characterized by their color as well as by their pH. Thus, the effluent collected at the anode has a yellowish color and a pH
neighbour of 4, while the effluent collected at the cathode has a color brownish and a pH close to 12.

Example 2 - Food sludge Agrifood sludge obtained in the processing industry meat is processed. It is a mud resulting from several treatments physico-chemical type DAF, in particular with ferric sulfate, on a mixture of meats consisting essentially of pork. This mud has summer filtered to remove all meat residue exceeding 2 mm. This mud East characterized by a resistivity of 244 SZ.cm.
After 24 hours of storage in a humid room at 13 ° Celsius and with a moisture content of 90%, the sludge is placed in the installation in batch with a volume of 1100 ml described in Example 1.
The pressure applied is the same as in the previous example.
The voltage applied for 6 hours to the electrodes is set to 8.5 volts and the voltage gradient is 0.5 Volt / cm. The volume of water drained is from 466 ml. The initial dryness measured for the feed slurry is 10% and that of the mud after treatment is 25.3%.
Example 3 - Food sludge The food-processing mud used in (example is of the same nature than the one treated in example 2, with the difference that it was stored during 1 week in the humid chamber. This sludge is characterized, before treatment, through a resistivity of 290 S2.cm. This sludge is subjected to a treatment in the even installation only in (example 1, for 6 hours and the conditions of pressure applied are also the same.
The applied voltage gradient is also 0.5 Volt / cm. In in this case, the volume of water drained is set to 280 ml.
While the initial dryness of the feed slurry was 9%, that of the final mud is 25%.

Example 4 - Food sludge Agrifood sludge from a slaughterhouse with resistivity of 308 S2.cm is treated, after 3 days of storage in a humid chamber, in batch in a rectangular cell equipped with a 185 cm2 section electrode.
The cell volume is 925 ml and the duration of treatment in the cell of 4 hours.
The voltage at the electrodes is 2.5 Volts / cm and the voltage gradient applied is also 0.5 Volt / cm and this time the volume of water drained is of 194 ml.
While the initial dryness of the mud was 14%, that of the mud after treatment is 40%.
Example 5 - Food sludge Agrifood sludge of the same nature as that treated in the previous example, but stored for a week in the humid chamber, is used for the realization of (example. The resistivity of the front buoy treatment is 3 6 S2. cm:
The duration of the treatment is 5 hours 30 minutes.
The voltage gradient applied to the electrodes is 1 Volt / cm and the volume of water drained is 122 ml.
Whereas the initial dryness of the mud was 8%, that of the mud after treatment is 25%.
Example 6 - Continuous municipal sludge cell A sludge with a resistivity of 22 S2 / cm, obtained by treatment biological effluent from a treatment plant in Victoriaville, Province of Quebec, Canada, is treated for 335 minutes in a continuous installation in cylinder shape as shown in Figure 6 and a volume of 24 liters.

The volume of water drained is 30; 2 liters and the volume of sludge is 80 liters.
The voltage applied to the electrode is 30 Volts and the gradient of voltage is 5 Volts / cm.
Whereas the initial dryness was 2.14%, that of the treated sludge in the lower part of the cell is 17.60%.
The effluents recovered during the treatment of the sludge in the examples above can be processed according to any of the sequences previously described electrocoagulation.
Example 7- Treatment of the effluents recovered in Example 6 The effluents recovered during (example 6 are, on the one hand an effluent anodic, coming from (anode, and on the other hand, a cathodic effluent derived from the cathode. The anodic effluent is acidic and the cathodic effluent is basic.
Each of the effluents has been treated individually and the mixture of these two the latter was also processed. When mixing the two effluents the training a precipitate was observed.
The effluents and the effluent mixture were treated using a device as illustrated in Figure 10. The electrodes used are formed aluminum and have dimensions of 16.5 cm x 25.5 cm. First, the pH of the effluents (or the mixture) was measured and then they were inserted into the reactor. About four liters of the effluent (or mixture) has summer introduced into the reactor and the latter was subjected to a direct current of which was applied consistently throughout the treatment, i.e.
period varying from 60 to 74 minutes. During this treatment, periodic withdrawals have been made for analysis purposes. The results of these treatments are presented in Table 1.

Table 1. Results of the treatment of various effluents by electrocoagulation.
Effluent Energy Charge pH pH Turbidit Color MES

final final electrical consumption (units) (mg / L) (kWh / m3) (Ah / m3) (T'TU) anodic 23.00 2310 6.01 4.04>750> 500 183 5.48 cathodic 12.65 2280 8.84 8.51 22 119 0 9.75 mixture 13.40 2000 6.64 7.03 10 44 1 (anodic and cathode)

Claims (88)

The embodiments of the invention, about which an exclusive right to property or lien is claimed, are defined as follows: 1. Process for treating sludge and / or fluids for the purpose reach an advanced level of purification comprising two sequences, the first sequence implementing an electro-osmosis process (SEO) is characterized in that:
a) sludge and / or fluids are treated by the combined action of electro-osmosis with the action of pressure and / or with the action of a system vibratory (such as ultrasound or electro-acoustic) in a reactor, said step (a) using the drainage of at least two effluents of different types, the first effluent comprising at least one pollutant is generated at the level of the cathode has a basic pH, preferably between 10 and 12, more preferably still around 11; and the second effluent comprising at less pollutant is generated at the anode is of an acidic pH, understood preferably between 4 and 6 more preferably still around 5;
and the second sequence implementing a process of electrocoagulation (SEC) is characterized in that:
b) treating at least one effluent obtained in the first sequence by passing an electric current through this effluent from way to electrocoagulate at least one pollutant it contains; and c) separating said electrocoagulated pollutant from said at least one treated effluent, the order in which the sequences are performed can be reversed, if first carry out the sequence (SEC), at that time, the effluent collected when implementation of the sequence (SEC) is used in place of sludge and / or fluid in the sequence (SEO). 2. Method according to claim 1, characterized in that the reactor step (a) also comprises other electrodes including at least one cathode and an anode intended to treat at least one effluent. 3. Method according to claim 2, characterized in that the electrodes intended to treat at least one effluent comprise a metal chosen from the group made up of aluminum, calcium and iron. 4. Method according to claim 2, characterized in that the electrodes intended to treat at least one effluent consist of aluminum, calcium or of iron. 5. Method according to claim 2, characterized in that said at at least one anode of the electrodes intended to treat at least one effluent is a soluble anode. 6. Method according to claim 2, characterized in that the electrodes intended to treat at least one effluent are inert electrodes. 7. Method according to claim 6, characterized in that the electrodes inert materials include titanium coated with iridium or platinum. 8. Sludge and / or fluid treatment process for the purpose reach an advanced level of purification comprising two sequences, the first sequence implementing an electro-osmosis process (SEO) is characterized in that:
a) sludge and / or fluids are treated by the combined action of electro-osmosis with the action of pressure and / or with the action of a system vibratory (such as ultrasound or electro-acoustic) in a first reactor, said step (a) implementing the drainage of at least two effluents from type different, the first effluent comprising at least one pollutant is generated at level of the cathode has a basic pH, preferably between 10 and 12, more preferably still around 11, and the second effluent comprising at least less pollutant is generated at the anode is of an acidic pH, understood preferably between 4 and 6 more preferably still around 5;
and the second sequence implementing a process of electrocoagulation (SEC) is characterized in that:
b) at least one effluent obtained is introduced into the first sequence in a second reactor fitted with electrodes, i.e. at least one cathode and at least one anode;
c) an electric current is passed through said effluent chosen in step (b) so as to electrocoagulate said at least one pollutant it contains; and d) separating said electrocoagulated pollutant from said at least one effluent, the order in which the sequences are performed may be reversed; if first carry out the sequence (SEC), at that time, the effluent collected when implementation of the sequence (SEC) is used in place of sludge and / or fluid in the sequence (SEO). 9. Method according to claim 8, characterized in that the electrodes of said second reactor comprise a metal chosen from the group consisting through aluminum, calcium and iron. 10. Method according to claim 8, characterized in that the electrodes of said second reactor consist of aluminum, calcium or iron. 11. Method according to claim 8, characterized in that said at at least one anode of said second reactor is a soluble anode. 12. ~ Method according to claim 8, characterized in that the anode and the cathode of said second reactor are inert electrodes. 13. ~ Method according to claim 12, characterized in that the electrodes inert materials include titanium coated with iridium or platinum. 14. ~ Process for treating sludge and / or fluids for the purpose reach an advanced level of purification comprising two sequences, the first sequence implementing an electro-osmosis process (SEO) is characterized in that:
a) sludge and / or fluids are treated by the combined action of electro-osmosis with the action of pressure and / or with the action of a system vibratory (such as ultrasound or electro-acoustic) in a first reactor, said step (a) implementing the drainage of at least two effluents from type different, the first effluent comprising at least one pollutant is generated at level of the cathode has a basic pH, preferably between 10 and 12, more preferably still around 11, and the second effluent comprising at least less pollutant is generated at the anode is of an acidic pH, understood preferably between 4 and 6 more preferably still around 5;
and the second sequence implementing a process of electrocoagulation (SEC) is characterized in that:
b) at least one effluent obtained is introduced into the first sequence and, where appropriate, an additive chosen from the group consisting of a source of F- ions, source of Cl- ions, source of Br- ions, source of ions I-, a source of CO3 2- ions and a mixture of said sources, in a second reactor provided with at least one cathode and at least one soluble anode comprising a source of Ca2 + ions, said at least one effluent comprising at least one orthophosphate; and c) an electric current is passed through said at least one effluent chosen in step (b) so as to cause diffusion of Ca2 + ions in said at least one effluent and thus form a precipitate consisting of an apatite or a mixture of apatites, the pH of said at least one effluent in step (c) being maintained at a value of around 8.9, the order in which the sequences are performed may be reversed, if first carry out the sequence (SEC), at that time, the effluent collected when implementation of the sequence (SEC) is used in place of sludge and / or fluid in the sequence (SEO). 15. Process for treating sludge and / or fluids for the purpose reach an advanced level of purification comprising two sequences, the first sequence implementing an electro-osmosis process (SEO) is characterized in that:
a) sludge and / or fluids are treated by the combined action of electro-osmosis with the action of pressure and / or with the action of a system vibratory (such as ultrasound or electro-acoustic) in a first reactor, said step (a) implementing the drainage of at least two effluents from type different; the first effluent comprising at least one pollutant is generated at level of the cathode has a basic pH, preferably between 10 and 12, more preferably still around 11, and the second effluent comprising at least less pollutant is generated at the anode is of an acidic pH, understood preferably between 4 and 6 more preferably still around 5;
and the second sequence implementing a process of electrocoagulation (SEC) is characterized in that:

b) at least one effluent obtained is introduced into the first sequence and, where appropriate, an additive chosen from the group consisting of a source of F- ions; a source of Cl- ions, a source of Br- ions, a source of ions I-, a source of CO3 2- ions and a mixture of said sources, in a second reactor provided with at least one cathode and at least one soluble anode comprising a source of Ca2 + ions, said at least one effluent comprising at least one orthophosphate; and c) an electric current is passed through said at least one effluent chosen in step (b) so as to cause diffusion of Ca2 + ions in said at least one effluent and thus form a precipitate consisting of at least one apatite, the pH of said at least one effluent in step (c) being maintained at a value about 8.9 the order in which the sequences are performed may be reversed, if first carry out the sequence (SEC), at that time, the effluent collected when implementation of the sequence (SEC) is used in place of sludge and / or fluid in the sequence (SEO). 16. Combined sludge and / or fluid treatment process for the purpose to reach an advanced level of purification and preparation of an apatite of formula:
Ca5 (PO4) 3X (I) or Ca10 (PO4) 6X2 (II) or of a mixture of apatites of formula (I) or (II), formulas in which X
represents an ion chosen from the group consisting of F-, Cl-, Br-, I-, OH-and CO3 2-, provided that when the apatite meets formula (I), X cannot represent CO3 2-, comprising two sequences, the first sequence implementing an electro-osmosis process (SEO) is characterized in that:
a) sludge and / or fluids are treated by the combined action of electro-osmosis with the action of pressure and / or with the action of a system vibratory (such as ultrasound or electro-acoustic) in a first reactor, said step (a) implementing the drainage of at least two effluents from type different, the first effluent comprising at least one pollutant is generated at level of the cathode has a basic pH, preferably between 10 and 12, more preferably still around 11, and the second effluent comprising at least less pollutant is generated at the anode is of an acidic pH, understood preferably between 4 and 6 more preferably still around 5;
and the second sequence implementing a process of electrocoagulation (SEC) is characterized in that:
b) at least one effluent obtained is introduced into the first sequence and, where appropriate, an additive chosen from the group consisting of a source of F- ions, source of Cl- ions, source of Br- ions, source of ions I-, a source of CO3 2- ions and a mixture of said sources, in a second reactor provided with at least one cathode and at least one soluble anode comprising a source of Ca2 + ions, said at least one effluent comprising at least one orthophosphate; and c) an electric current is passed through said at least one effluent chosen in step (b) so as to cause diffusion of Ca2 + ions in said at least one effluent and thus form a precipitate consisting of an apatite of formula (I) or (II), or of a mixture of apatites of formula (I) or (II), the pH of said effluent to step (c) being maintained at a value of approximately 8.9, the order in which the sequences are performed may be reversed, if first carry out the sequence (SEC), at that time, the effluent collected when implementation of the sequence (SEC) is used in place of sludge and / or fluid in the sequence (SEO). 17. The method of claim 16, for the preparation of an apatite of formula (I) or (II) where X represents OH-, characterized in that, in step (b) said at at least one effluent used contains an orthophosphate without adding said additive. 18. Method according to any one of claims 14 to 17, characterized in that the orthophosphate is present in said at least one selected effluent at step (b) at a concentration of 50 ppm to 300 ppm. 19. The method of claim 18, characterized in that the orthophosphate concentration is between 75 ppm and 250 ppm. 20. The method of claim 19, characterized in that the Orthophosphate concentration is around 120 ppm. 21. Method according to any one of claims 14 to 20, characterized in that the second reactor consists of a conductive material. 22. Method according to claim 21, characterized in that the material conductor is a metal. 23. The method of claim 21 or 22, characterized in that the second reactor is of cylindrical or parallelepiped shape. 24. The method of claim 23, characterized in that the reactor is cubic in shape. 25. Method according to any one of claims 21 to 24, characterized in that the second reactor is used as a cathode. 26. Method according to any one of claims 14 to 25, characterized in that the cathode of said second reactor used generates OH- ions. 27. Method according to any one of claims 14 to 26, characterized in that said at least one anode of said second reactor is constituted a mixture comprising a source of Ca2 + ions, a support and water. 28. The method of claim 27, characterized in that the Ca2 + ions are present in the mixture in a proportion of 15 to 40% by weight, for relative to the total weight of the mixture. 29. Method according to claim 28, characterized in that the proportion Ca2 + ions in the mixture is about 25% by weight, relative to the weight total of the mixture. 30. Method according to any one of claims 27 to 29, characterized in that the source of Ca2 + ions comprises calcium carbonate. 31. Method according to any one of claims 27 to 30, characterized in that the support is present in the mixture in a proportion of 40 to 60%
by weight, relative to the total weight of the mixture. 32. Method according to claim 31, characterized in that the proportion of the support in the mixture is about 50% by weight, relative to the weight total of the mixture. 33. Method according to any one of claims 27 to 32, characterized in that the support comprises silty clay, ceramic or concrete driver. 34. Method according to claim 33, characterized in that the concrete conductor includes conductive industrial waste. 35. Method according to claim 34, characterized in that the waste industrial conductor includes titanium and / or iron. 36. Method according to claim 33, characterized in that the support includes silty clay. 37. Method according to any one of claims 27 to 36, characterized in that water is present in the mixture in a proportion of 2 to 6% by weight, based on the total weight of the mixture. 38. Method according to claim 37, characterized in that the proportion of water in the mixture is between 3 and 5% by weight, relative to the weight total of the mixture. 39. Method according to any one of claims 27 to 38, characterized in that said at least one anode further comprises a rod consisting of a conductive material, said rod being coated with said mixture. 40. Method according to claim 39, characterized in that the material conductor includes iron. 41. Method according to claim 39 or 40, characterized in that the conductive material includes graphite. 42. Method according to claim 41, characterized in that the material conductor includes titanium coated with iridium. 43. Method according to any one of claims 27 to 42; characterized in that said mixture is coated with a membrane permeable to Ca2 + ions. 44. Method according to claim 43, characterized in that the membrane includes geotextile material. 45. Method according to any one of claims 14 to 20, characterized in that said at least one cathode and said at least one anode of said second reactor are planar electrodes. 46. Method according to any one of claims 14 to 20, characterized in that the cathode and the anode of said second reactor are electrodes cylindrical. 47. Method according to any one of claims 14 to 46, characterized in that the diffusion of Ca2 + ions is favored by neutralization ions H + by anions from the Ca2 + ion source. 48. Method according to any one of claims 14 to 47, characterized in that the electric current used is a direct current having a intensity between 1 and 100 A. 49. Method according to claim 48, characterized in that the intensity of the current is around 80 A. 50. Method according to any one of claims 14 to 49, characterized in that the electric current used is a direct current having a difference from potential from 1.6 to 36.0 volts. 51. Method according to claim 50, characterized in that the difference current potential is around 5 volts. 52. Method according to any one of claims 8 to 51, characterized in that electrocoagulation is carried out in step (c). 53. Method according to any one of claims 1 to 7, characterized in that electrocoagulation is carried out in step (b). 54. Method according to any one of claims 1 to 13, characterized in that the mud is chosen from the group consisting of mud organic and / or inorganic such as colloidal sludge, paper mills, all sludge from chemical and / or biological treatment, dairy sludge, sludge slaughterhouse, sludge resulting from the processing of slurry, in particular from slurry from pork, sludge resulting from treatment plants. 55. Method according to any one of claims 14 to 52, characterized in that the sludge to be treated comprises at least one orthophosphate. 56. Method according to claim 54 or 55, characterized in that chemical agents for improving sludge treatment are added to said mud, the chemical agents added are preferably those which facilitate the dehydration and these are preferably polymeric compounds. 57. Method according to any one of claims 1 to 56, characterized in that the sludge treated in the first sequence is subjected to a electro-osmosis under the following conditions:
- metal and / or steel and / or lead oxide and / or electrodes perforated (s);
- voltage gradient between the electrodes varying from 0.5 V / cm to 15 V / cm, preferably the voltage varies from 0.5 V / cm to 10 -V / cm, more preferably still from 0.5 to 5 V / cm; and - duration of electro-osmosis from 1 to 6 hours, preferably from 4 to 5 hours. 58. Method according to claim 57, characterized in that a precipitate appears when mixing the effluents collected at the electrodes in the first sequence, at the anode and at the cathode, during the treatment and, preferably, said precipitate after recovery is recycled in the process. 59. Method according to claim 58, characterized in that a part of the mud located near one of the electrodes of the first reactor is subject to a pressure. 60. Method according to claim 59, characterized in that the pressure is generated on the mud by setting in motion at least one of the electrodes, of preferably using mechanical and / or pneumatic means, such as a piston or dead load. 61. Method according to claim 59 or 60, characterized in that said electrode is the anode. 62. Method according to claim 61, characterized in that the pressure generated in the mud, by the anode in the first sequence, varies depending of the consistency of the mud, preferably said pressure increases progressively than the consistency of the mud increases. 63. Method according to any one of claims 57 to 62, characterized in that the pressure exerted on the mud is zero at the start of electro-osmosis and gradually increased when the mud is subjected to a pressure. 64. Method according to any one of claims 57 to 63, characterized in that the two electrodes are perforated and a drop of liquid positioned in the center of the first reactor has to travel only half of the distance between the electrodes. 65. Method according to any one of claims 1 to 64, characterized in that the electrode voltage in the first sequence is maintained substantially constant throughout the process and / or during stages successive to during which the voltages are adjusted to a fixed value. 66. Method according to any one of claims 1 to 65, characterized in that at least one electrode in the first sequence (preferably the cathode) is fixed and / or at least one electrode (preferably the anode) is mobile. 67. Method according to any one of claims 1 to 66, characterized in that at least one electrode in the first sequence is chosen so at allow the flow of effluents. 68. Method according to claim 67, characterized in that at least one of the electrodes is of the perforated type. 69. Method according to any one of claims 1 to 68, characterized in that at least one and preferably at least two means of detention (tanks transit) are present in the first sequence near the electrode (of preferably near the mobile electrode), the first means of retaining being located near an upper part of the electrode and collects a gas fraction (essentially consisting of at least one of the group's gases consisting of H2, O2, NH3 and CO2 and possibly a little water) produced in the upper part of the electrode and which preferably passes through channels and / or orifices present in the upper part of the electrode and the second means retained being preferably located near a lower part of the electrode and collects a liquid part (mainly water) produced in the part low of the electrode and which preferentially passes through channels and or orifices present in the lower part of the electrode. 70. ~~ Method according to any one of claims 1 to 69, characterized in that the sludge to be treated is inserted into the first reactor nearby at minus one of the electrodes, preferably between two electrodes. 71. ~~ Method according to any one of claims 1 to 70, set works continuously or in batch. 72. ~~ Method according to any one of claims 1 to 71, characterized in that the anode and the cathode in there first. sequence have a section different, preferably, one of the electrodes is inside the other, more preferably still coaxially. 73. ~~ Method according to any one of claims 1 to 59 implementation works continuously. 74. ~~ Method according to claim 73, characterized in that the pressure is generated on the mud (near one of the electrodes in the hands), preference to using mechanical and / or pneumatic means. 75. ~~ Process according to claim 73 or 74, characterized in that the pressure generated in the mud varies according to the consistency of the mud, of preferably said pressure increases as the consistency of the mud increases. 76. Method according to any one of claims 73 to 75, characterized in that the pressure exerted on the mud is zero at the start of electro-osmosis and gradually increased during the electro-osmosis process when the mud is subjected to pressure. 77. Method according to any one of claims 73 to 76, characterized in that the two electrodes are perforated and a drop of liquid positioned in the center of the cell has to cover only half of the distance between the electrodes. 78. Method according to any one of claims 73 to 77, characterized in that the voltage at the electrodes is maintained substantially constant during the whole process and / or during successive stages during which the voltages are adjusted to a fixed value. 79. Method according to any one of claims 73 to 78, characterized in that at least one electrode (preferably the cathode) is fixed and / or at least one electrode (preferably the anode) has a variable section or all the electrodes have a constant section. 80. Method according to any one of claims 73 to 79, characterized in that the anode and the cathode have a different section, of preference, one of the electrodes is inside the other, more preferably more coaxially. 81. Method according to claim 80, characterized in that at least one of the electrodes in the first sequence is hollow. 82. Method according to any one of. claims 73 to 81, characterized in that at least one electrode is chosen so as to allow effluent flow. 83. The method of claim 82; characterized in that at least one of the electrodes is of the perforated type. 84. Method according to any one of claims 73 to 83, characterized in that the sludge to be treated in the first sequence constitutes a ring having a thickness which is at least twice the thickness distance from the central axis of the cell to the point furthest from a wall at least one of the electrodes. 85. Method according to any one of claims 73 to 84, characterized in that the sludge to be treated is inserted at a part higher at least one of the electrodes of the first reactor, preferably between two electrodes. 86. Process according to any one of claims 73 to 85, characterized in what the first sequence or the second sequence can be repeated many time. 87. Use of one of the methods according to any one of claims 1 to 88 for the depollution of sludge; for increasing the concentration of solids in sludge (dry), for reduction of the concentration of cationic pollutants in sludge, for the concentration of the cationic pollutants in the effluent collected at the cathode, for the reduction of anionic pollutants in sludge, for the concentration of pollutants anionic in the effluent collected at the anode and / or for the compaction of sludge. 88. Use of a method according to any one of claims 1 87, characterized in that the sludge is dewatered for protection purposes of the environment.