CH701271A2 - aqueous effluents decontamination device for separation by immiscible phases and germicidal treatment and / or oxidant to the reduction of BOD and / or COD. - Google Patents

Abstract

The invention relates to a device for decontaminating an aqueous effluent characterized in that it comprises an immiscible liquid phase separator of the aqueous effluent to be treated combined with a treatment unit by aqueous phase germicidal and / or oxidizing for the COD (Chemical Oxygen Demand) and / or BOD (Biological Oxygen Demand) removal of the separated aqueous effluent.

Description

The present invention relates to a device for decontaminating aqueous liquid effluents by immiscible phases separation and germicidal and / or oxidizing treatment for the purpose of reducing the COD (chemical oxygen demand), and the BOD, (Biological oxygen demand), by passage, firstly, the aqueous fluid to be treated in a phase separator commonly called de-oiler, then by introduction in infinitesimal amount, in the same "deoiled" aqueous effluent, a second phase aqueous germicidal and / or oxidizing, during an intimate contact with the latter, generated by a venturi using effluent to be treated as the driving fluid, or any type of agitation for a mixture of the same type between the two phases concerned.

The device allows to introduce into the fluid to be treated after separation of the immiscible phases to minimize the consumption of germicidal agents, from chemistry, injection, or aspiration by venturi, but also that of germicidal agents carried out upstream of the mixture of the germicidal and / or oxidizing aqueous phase and of the effluent, such as the production of nascent oxygen which is extremely germically active, but also on the chemical level, with a view to the simultaneous reduction of biological oxygen demand (BOD), and chemical oxygen demand (COD).

The present invention will treat for the example of a germicidal aqueous phase, carried out in situ of the process, charged nascent oxygen to be introduced into an aqueous effluent, in order to lower its bacteriological contamination, aerobic germs and anaerobic, and reduce the COD by oxidation of the mineral or organic compounds present in the medium to be treated.

The nascent oxygen may be derived from a catalytic reactor, the controlled decomposition of a peroxide, an electrolysis, or any other process capable of producing this element in its nascent form, the amorphous form n ' being very little reactive, or not at all, depending on the medium, for the reduction of BOD or COD.

Various methods are known to reduce bacterial contamination by spraying a germicidal aerosol on a contaminated surface, as mentioned in the patent registered under US 4,678,658.

No. 5,688,387 also discloses the production of incipient oxygen by electrolysis, using electrodes made of perforated aluminum, through which the electrolyte is pumped or pulverized. to ensure maximum contact.

It is also known from the patent registered under US Pat. No. 5,424,032, the production of oxidants for the treatment of contaminated water, in combination with the UV treatment, cooling towers.

Other methods are also known for the decontamination of aqueous media, such as the use of halogens or compounds derived from them, as mentioned in the patent registered under number US 4818 532, referring to brominated compounds. . The introduction of decontaminating agents in the media to be treated is either by pumping or spraying.

Also known from WO 98/047 826, the introduction of microbubbles of ozone gas using a hydro ejector in the aqueous fluid to be treated, from any ozonizer, which hydro ejector acts as a static mixer. It is also mentioned in this patent the possibility of injection of hydrogen peroxide.

Finally, it is known from the patent registered under the number WO 98/047 826, the introduction of ozone gas under pressure in a hydro-ejector in aqueous medium, for a bacteriological only decontamination.

In total opposition to this state of the art, whose effectiveness remains very hypothetical when the bacterial flora is varied and fed continuously by the presence of important organic, as is the case in industrial effluents, and generate a chemical oxygen demand (COD) consistent for their oxidation for their discharge as non-polluting effluent, the present invention ensures, by the introduction of the aqueous germicidal oxidizing phase, the microbiological decontamination and the lowering of the COD to a residual threshold close to zero, because nevertheless continuously fed in a continuous normal cycle in industrial production.

For this purpose, the invention has for its first object, mounted upstream of the oxidizing phase in the device, the prior separation of two immiscible liquid phases when present, first generated in a chamber of rest by natural settling based on the difference in density of the liquids to be separated, said separation chamber having an elimination of the light phase from above, and the densest phase at a low point, the latter remaining hermetically closed until that the denser phase is effectively separated from the less dense, and causes the opening of a weighted valve at a mean density between the two densities of the fluids to be separated, for the elimination of said liquid phase the denser by the low point of the device previously called de-oiler.

Patent EP 0 389 346 discloses the separation of two immiscible liquids on a fiber bundle having a preferential wettability by one of the two liquids, which fiber may be arranged upstream or downstream of a desalter of crude oil.

Also known from patent WO 2006/087 575, the separation of two immiscible liquids based on coalescent filtration, and using for this purpose the hydrophobic, or oleophilic, open-cell foam of the polyurethane type, in combination with a flow of the fluid to be treated through baffles to promote the separation of the two immiscible liquids.

Also known from WO 2007/108 012, the separation of oil and seawater used as ballast on ships by centrifugation associated with so-called hydrodynamic cavitation, and a consequence of this treatment would be to generate a disinfection of the aqueous phase, the effectiveness of which remains to be demonstrated.

WO 2008/110 060 discloses a separating device on a hydrophilic film, non-woven, said anti-priming for the separation of two immiscible liquids.

Patent EP 1 974 784 discloses a filter made of hydrophobic organic fiber, associated with an inorganic fiber of the glass fabric type, which separates an oily phase from an aqueous phase.

Finally, JP 2007 160 264 discloses the separation of two immiscible liquid phases by a succession of particulate filtration, and adsorption of the residual organic phase.

The present invention does not rely on the techniques previously mentioned in the patents dealing with the subject, such as coalescence, or ultrafiltration, centrifugation, or electro filtration.

It is based on decantation in a rest chamber, the two immiscible phases having separated by gravity, thus causing the opening or closing of a weighted valve at a mean density between the two densities of the fluids. to separate.

In a second part of the process, the subject of the invention is the production of a germicidal and oxidizing aqueous phase introduced into the effluent to be treated in divided form, for an immediate oxidation reaction in the flow of a venturi for the example concerned, created by the aspiration of the oxidizing germicidal fluid during the passage of the fluid in a concentric tubular pipe, called venturi. The so-called "duck" circulation of the motor fluid consisting of the effluent to be treated is provided by a pump.

A second pump is mounted on a reservoir containing water, as a transfer fluid, filled to three quarters of its capacity for the example, recycled permanently (in duck) by the second pump mentioned above. The permanently recycled water passes through a catalytic reactor capable of generating nascent oxygen, to reach the aforementioned tank, thus allowing the circulating water to be then engorged with incipient oxygen.

This water, thus oxidizing, is introduced into the effluent to be treated by the venturi constituted by its suction during the passage of the motor fluid.

For the record, the motor fluid that enters under pressure in the venturi flows in a pipe whose section decreases. This results in an increase in the flow velocity, and consequently a decrease in the static pressure. The latter makes it possible to draw a liquid or a gas in the ejector thus constituted, through the suction port in turbulent flow, generating an immediate mixing of the driving fluid and the aspirated fluid, that is, for the example described, a eminent contact between the two phases, oxidizing product and product to be treated.

There is thus no direct contact, upstream of the venturi, between the fluid contained in the emitter reactor of the water containing the nascent oxygen, and the fluid to be treated which undergoes the elimination of the bacterial flora. , aerobic and anerobic, as well as the reduction of COD, in proportion to the treatment time, which is dependent on the bacterial flora present and the concentration of elements to be oxidized initially. A small portion of the water of the flask is entrained with the oxidant by suction in the fluid to be treated.

The amount of oxygenated water extracted from the flask is a function of the calibration of the generated venturi. It is of the order, for the example, of 0.5 liter / hour for a volume of fifty liters of water engaged in the aforementioned balloon, with a flow of the motor fluid of the venturi (effluent to be treated) of 2800 liters /hour.

Compensation of water losses is achieved by an addition determined by the detection of the level established in the reservoir emitting oxidizing water. The duration of the treatment is dependent on the concentrations of the elements to be removed by oxidation, and the capacity of the incipient oxygen production reactor.

A device for the germicidal treatment of aqueous media is thus produced by the introduction of a germicidal and / or oxidizing liquid in the said liquid media to be decontaminated, without using electrolysis, UV radiation, or the use of halogens or compounds derived therefrom, which germicidal and / or oxidizing liquid may be introduced into the effluent to be decontaminated, in addition to a venturi, by any appropriate means, such as for example an injection pump, whatever the type chosen, or by gravity.

The invention will be better understood anyway using the following description, with reference to the accompanying schematic drawings representing, for example, an embodiment of the bacteriological decontamination device and abatement of COD in an aqueous medium.

FIG. 1 is a schematic diagram of the immiscible liquid phase separator.

FIG. 2 is a schematic diagram of the hydraulic circuit, and the positioning in space of the elements constituting the germicidal and oxidizing device for the treatment of a contaminated liquid phase.

Considering first, FIG. 1, the device for separating immiscible liquid phases comprises an enclosure 1, called the rest chamber of the mixture to be separated 2, introduced into the chamber 1 by the pipe 3, which can be pierced with a multitude of holes 4, for reduce the turbulence of the liquid 2 during its introduction into the chamber 1, and thus facilitate the settling phase in the chamber 1.

The mixture of immiscible liquid phases to be separated is introduced by any suitable means through the tubing 3 into the chamber 1.

The light liquid phase decanted is positioned in the upper part of the chamber 1, without being able to exceed the level 5 constituting the limit of the gravitational flow of the light phase through the tubing 6 having an air vent 7 , to maintain a constant level of liquid in the chamber 1, itself at the same (atmospheric) internal pressure provided by the tubing 8.

Maintaining level 5 of the chamber 1 is ensured by the opening and closing of the valve or ball valve 9, the sealing is made effective by the flexible seal 10, via the float 11 whose density of the material is between the two densities of the fluids to be separated injected into the chamber 1 by the tubing 3, which float 11 is secured to the ball 9 of the valve, said ball or ball, by the rod rigid 12.

When the float 11 is immersed in the light liquid phase 2 decanted, said float being of a density greater than that of the aforesaid phase 2, the ball 9 is positioned in contact with the seal 10 ensuring the seal between the rest chamber 1, and the chamber 13 which receives only the separated liquid phase 14, usually consisting essentially of water or stable aqueous emulsion.

When the level of the densest liquid phase is the largest, in mass or volume, in the chamber 1, the float 11, of a density less than that of the densest liquid phase in which it is then immersed, physically ascends into the dense phase and thus releases the ball 9 from its contact with the seal 10; the tightness of the valve is then no longer ensured, the most dense liquid phase flows through the tubing 15.

The movement of the float 11, from bottom to top or from top to bottom, is effected at the discretion of the presence at said float 11 of the so-called light liquid phase or the so-called dense liquid phase.

The float 11 performs the aforementioned task only when a liquid phase, light or dense, is perfectly decanted, an intermediate density mixing phase can not trigger its movement, in order to drive in turn the displacement of the ball 9 for the flow or not of the dense phase through the orifice 17, which separates the two chambers 1 and 13.

The tubing 15 for removing the dense phase decanted 14, whose flow is gravity, is positioned to ensure a constant level of liquids in the bodies 1 and 13 of the immiscible phase separator, at a level of less, as to the flow, than that of the flow of the light phase through the tubing 6, the complement of the previous liquid level to the outlet 6 consisting of the light phase; maintaining the total filling of the apparatus at the maximum level imposed by the outlet pipe 6 of the light liquid phase is obviously ensured by the displacement of the float 11 associated with the valve 9 and its seal 10, which regulates the withdrawal of the one or the other liquid phase decanted according to its density, and the immersion of the float 11 in one or other of the decanted phases.

The chamber 13 may optionally receive a spongy substrate, not soluble in the liquids in the presence to be separated, in order to trap traces of residual hydrocarbons in the case of the most common separation of the oil / water mixture, and allow the release by settling of the light phase which rises in the chamber 1 by density difference with the denser phase, and eliminated by the tubing 6 intended for this purpose.

The gravity flow of the dense liquid phase through the tubing 15 is ensured by putting the latter at atmospheric pressure through the tubing 16.

When the separation of the liquid phases of the effluent to be treated is effective, the germicidal and / or oxidizing treatment for the abatement of the BOD and the COD can then be engaged in accordance with the device shown in FIG. 2.

This new device comprises a water tank 18, filled to about three quarters of its capacity 19.

A first transfer pump 20 whose physical characteristics are in adequacy with the flow rate and the pressure required for the continuous flow of water in the device, connected to the balloon 18 by the manifold 21, feeds a reactor 22 in-situ production of incipient oxygen, then the return of the oxidizing water through the pipe 23 to the top of the balloon 18 free of water in its upper part 24.

A tubing 25 ensures the venting of the balloon 18.

A second pump 26 for transferring liquid, whose physical characteristics are also in adequacy with the flow rate and the necessary pressure, ensures the continuous circulation of the effluent to be treated 27 contained in the tank 28, by the tubing The effluent to be treated can be introduced into the tank by gravity, by pumping or any other appropriate method according to the configuration of the process. According to the embodiment shown in FIG. 2, the effluent to be treated comes from the tubing 15 for removing the decanted dense phase. In some examples where only the germicidal and / or oxidative treatment phase is carried out, as explained at the end of the description, the tubing 15 is obviously not necessary.

A tubing 31 of reduced diameter and concentric in the recycle tubing 30 of the effluent to be treated 27, constitute a venturi for the suction of oxidizing water from the balloon 18, for a regulated introduction into the effluent 27 concerned, during an eminent contact by its turbulent flow within the latter in the tubing 30 at the venturi.

The extreme reactivity of the oxygen in its nascent form with the contaminant elements contained in the fluid to be treated 27, ensures the simultaneous reduction of the biological oxygen demand (BOD), and the chemical oxygen demand (COD) ).

A makeup water for the maintenance of the level 19 of the latter is obviously carried out directly in the balloon 18 in an industrial environment, by an annex tubing not shown in the block diagram of FIG. 2.

The device for decontaminating aqueous effluents by immiscible phases separation and germicidal and / or oxidizing treatment for the abatement of COD and BOD described above, is applicable to the treatment of industrial effluents, effluents food plants, aqueous effluents from cooling towers, effluents from the hospital environment, both for biological oxygen demand (BOD) and chemical oxygen demand (COD) separately or concomitantly.

It goes without saying that the invention is not limited to the embodiments that have been described above as examples; it embraces, on the contrary, all variants of implementation and application respecting the same principle. Thus, one would not depart from the scope of the invention by applying this device to cold sterilization in the food industry, as for example, for milk, fruit or vegetable juices, or wine, or the disinfection of washing water of fresh products intended for human consumption. It is the same for the disinfection of swimming pool water, and the BOD and COD removal of agro-industrial effluents.

In addition, one would not move away from the scope of the invention by applying the device to the decontamination of ambient air, limiting it to the production of an aerosol, considering obviously the performance of a material in line with the volume of air to be treated in air conditioning.

Finally, one would not depart from the scope of the invention by applying only the decontamination device of an aqueous effluent by means of immiscible liquid phase separator of the aqueous effluent to be treated in COD reduction (Fig. 1) independent of the water-based and / or oxidizing aqueous treatment device for the removal of the COD and / or BOD of the aqueous effluent (Figure 2). ) and reciprocally.

Indeed, the device for separating immiscible liquids on the one hand and the germicidal device and BOD / COD abatement on the other hand, can be used simultaneously or separately depending on the liquid effluents to be treated, which can be process water or wastewater. The liquid effluents to be treated may contain biological pollutants (BOD) or chemical contaminants (COD) that require the reduction of BOD and / or COD. This is possible according to the present invention by separately using the immiscible liquid separation properties thus contributing to the reduction of BOD and / or COD, or separately the oxidizing properties of the process (BOD and / or COD), or simultaneously the oxidizing properties and the separation properties of immiscible liquids.

For example, for the abatement of COD in the aqueous effluents polluted by hydrocarbons such as washing water in the mechanical industry, the device for separating immiscible liquids can be used separately since it allows by itself the separation of pollutants from the polluted liquid matrix since the pollutant load is in the immiscible phase in the aqueous phase.

In another example, the reduction of the COD in the aqueous effluents of the organic chemistry requires both a separation of immiscible liquids and an oxidation.

Note that the principle of separate use of the immiscible liquid separation device on the one hand and the germicidal device e of BOD / COD abatement on the other, can be applied for the microbiological disinfection of products. of the fourth range dan: agri-food (eg prepackaged salads, or vegetables of the same type) and the reduction of BOD in the wash water. Indeed, this; effluents do not contain immiscible liquids and their treatment does not require the use of the device for separating non-miscible liquids.

One can also mention the treatment of aqueous effluents of the sugar industry which contain BOD but does not require: the use of germicidal properties.

On the other hand, the two separation and treatment devices will be used for agro-industrial aqueous effluents such as those for example from the dairy industry which are contaminated with immiscible liquids such as fatty substances and having a phase aqueous high BOD content.

Claims (13)

1. Device for decontaminating an aqueous effluent characterized in that it comprises an immiscible liquid phase separator of the aqueous effluent to be treated for the purpose of reducing the COD (chemical oxygen demand). 2. Device for decontaminating an aqueous effluent according to claim 1, characterized in that the immiscible liquid phase separator consists of a rest chamber (1) in which is injected by a pipe (3) a liquid mixture of immiscible phases (2), for phase separation by settling in a non-turbulent medium. 3. Device for decontaminating an aqueous effluent according to claim 2, characterized in that it comprises a drain valve of the rest chamber (1) consisting of a closure valve (9) sealing by a seal (10), the valve being connected by a rod (12) to a float (11) whose density is between the two densities of the fluids to be separated injected into the enclosure (1). 4. Device for decontaminating an aqueous effluent according to claim 3, characterized in that the elimination of the decanted light phase is effected by a pipe (6) located on the upper part of the separator, when the float (11). is immersed in said light phase, and the dense phase decanted by the tubing (17) positioned at the lower part of the rest chamber (1), via the valve (9), when the float is immersed in the the densest liquid phase. 5. Device for decontaminating an aqueous effluent according to claims 1 to 4, characterized in that the maintenance of the presence of the liquids to be separated in the bodies (1) and (13) perfectly full of the separator, is provided by an adjustment levels of elimination of the dense phase by the tubing (15) provided for this purpose, and the tubing (6) for the elimination of the light phase. 6. Device for decontaminating an aqueous effluent according to any one of the preceding claims, characterized in that the immiscible liquid phase separator of the aqueous effluent to be treated is associated with a treatment unit by aqueous phase germicide and / or oxidizing for COD (chemical oxygen demand) and / or BOD (biological oxygen demand) removal of the separated aqueous effluent. 7. Device for decontaminating an aqueous effluent according to claim 6, characterized in that the treatment unit comprises a catalytic reactor (22) which generates nascent oxygen ensuring an immediate reaction with contaminant elements contained in the fluid to be treated in permanent circulation during the treatment period. 8. Device for decontaminating an aqueous effluent according to claim 7, characterized in that the treatment unit comprises a flask (18) containing circulating water, by means of a pump (20) through the reactor catalytic converter (22) which generates reactive nascent oxygen, this incipient water / oxygen mixture being conveyed through a pipe (31) by suction by a venturi created by the concentricity of this tubing (31) and the tubing (30). ) of circulation of the fluid to be treated (27), conveyed by a pump (26) through the suction pipe (29) using said fluid to be treated (27) as the driving fluid of the venturi thus formed, ensuring an immediate reaction with the contaminant elements contained in the fluid to be treated in constant circulation during the treatment period, from the storage tank (28) via the suction pipe (29) integral with the circulation pump (26) of the effluent to be treated. tra iter (27) and the discharge pipe (30). 9. A device for decontaminating an aqueous effluent according to claim 8, characterized in that the decontamination of the fluid (27) takes place when the so-called oxidizing water from the catalytic reactor (22) and contained in the balloon (18). is introduced into the fluid to be treated (27), during an eminent contact in the venturi consisting of two concentric tubes (30) and (31), and its turbulent flow within the latter. 10. Device for decontaminating an aqueous effluent according to claim 8 or 9, characterized in that it allows to introduce into the fluid to be treated (27) germicidal agents from the chemistry or made upstream of the mixture of water from the flask (18) and the effluent to be treated (27) in the venturi intended for this purpose, and created by the concentricity of the tubes (30) and (31) conveying the fluids into contact, such as the production of nascent oxygen that is highly germically active in a catalytic reactor (22) integrated in the device, and chemically for the simultaneous reduction of biological oxygen demand (BOD) and chemical oxygen demand (COD). 11. Device for decontaminating an aqueous effluent according to one of claims 7 to 10, characterized in that the nascent oxygen may be from a catalytic reactor (22), the controlled decomposition of a peroxide, d electrolysis, or any other process capable of producing this element in its nascent form. 12. A decontamination device for an aqueous effluent according to one of claims 8 to 11, characterized in that the nascent water and oxygen mixture is introduced into the fluid to be treated (27) by a venturi consisting of two concentric tubes (30). ) and (31) conveying the germicidal and / or oxidizing fluid, as well as the fluid to be treated (27), or introduced into the same effluent to be treated (27) by any appropriate means such as a pump whatever the type used . 13. A device for treating an aqueous effluent characterized in that it comprises a treatment unit by aqueous phase germicidal and / or oxidizing for the reduction of COD (chemical oxygen demand) and / or BOD (biological oxygen demand) of the separated aqueous effluent, the treatment unit comprising a catalytic reactor which generates nascent oxygen to ensure an immediate reaction with contaminating elements contained in the aqueous effluent to be treated in permanent circulation during the duration of treatment.