CA1147290A - Apparatus for electrochemical purification of contaminated liquids - Google Patents
Apparatus for electrochemical purification of contaminated liquidsInfo
- Publication number
- CA1147290A CA1147290A CA000348358A CA348358A CA1147290A CA 1147290 A CA1147290 A CA 1147290A CA 000348358 A CA000348358 A CA 000348358A CA 348358 A CA348358 A CA 348358A CA 1147290 A CA1147290 A CA 1147290A
- Authority
- CA
- Canada
- Prior art keywords
- foam
- chamber
- ejector
- settling chamber
- electrocoagulation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
- C02F1/465—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electroflotation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
- B01D17/02—Separation of non-miscible liquids
- B01D17/0205—Separation of non-miscible liquids by gas bubbles or moving solids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
- B01D17/06—Separation of liquids from each other by electricity
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D21/00—Separation of suspended solid particles from liquids by sedimentation
- B01D21/0009—Settling tanks making use of electricity or magnetism
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D21/00—Separation of suspended solid particles from liquids by sedimentation
- B01D21/10—Settling tanks with multiple outlets for the separated liquids
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D21/00—Separation of suspended solid particles from liquids by sedimentation
- B01D21/24—Feed or discharge mechanisms for settling tanks
- B01D21/2433—Discharge mechanisms for floating particles
Abstract
Abstract of the Disclosure An apparatus for electrochemical purific-ation of contaminated liquids comprises a settling chamber having outlet pipes for discharging purified liquid and waste and communicating with an electro-coagulation chamber arranged in said settling chamber and comprising in its bottom portion a system of soluble electrodes. An inlet pipe is provided for feeding contaminated liquid into the electrocoagulation chamber above the soluble electrodes. An inlet pipe is also provided for feeding an electrolyte into the electrocoagulation chamber and a device is provided for removing foam from the apparatus as liquid is discharged into the coagulation chamber into the settl-ing chamber. The foam-removing device has a pipeline for transferring foam outside the settling chamber and is provided with a bell shaped opening at one end thereof and having the other end communicating with the outlet pipe for discharging waste. The pipeline for transferring foam is rotatable in a hori-zontal plane, and the bell shaped opening is arranged substantially above the settling chamber. This pipeline is provided with an air injector for drawing foam into the bell shaped opening and transferring it through the pipeline to the open end thereof. The invention makes it possible to enhance the efficiency of the apparatus and to improve the stability of the pur-ification process.
Description
~7Z910 The present invention relates to apparatus for purifying contaminated liquids and more particularly to apparatus for electrochemical purification of liquids.
The invention may be imployed for purifying liquids contaminated with organic substances, mechanical ! suspensions, surfactants, and the like.
The invention is particularly useful for pur-ifying liquids contaminated with petroleum products, such as waste waters containing oils and greases.
Apparatus for electrochemical purification of liquids, in particular those where liquid is pur-ified by electroflotation and electrocoagulation method~, have recently found ever increasing application owing to their high performance capabilities.
Known in the art are apparatus for electro-chemical purification of liquids is accomplished either periodically, i.e. in batches, or continuously, the latter apparatus seem to be more promising.
There is also known an apparatus for electro-chemical purification of contaminated liquids compris-ing a settling chamber housing an electrocoagulation chamber installed coaxially therewith, a system of soluble electrodes in the latter chamber, an inlet pipe for discharging purified liquid, and a device for re-moving foam from the apparatus (see, for instance, U.S.
Patent No. 3,505,188).
The device for removing foam from the above apparatus may take the form of a rotatable scraper mounted in the top portion of the settling chamber, or of a conveyor belt provided with paddles secured thereto.
B
1147Z~30 With such a structural arrangement of the device, a part of heavy fractions of the foam (free coagulants of electrode metal hydroxides, particles of contaminants etc.) are thrown with the scraper into the liquid contained within the settling chamber. If this settling chamber is not high enough, the above fractions are entrained by the liquid flow and carried into the pipe for discharging purified liquid, which adversely affects the efficiency of the purification process.
There is known an apparaLus or electro-chemical purification of contaminated liquids described in USSR Inventor's Certificate No. 644,738 granted to Nazaryan et al, October 6, 1978~ and comprising a settling chamber having outlet pipes for discharging purified liquid and waste and communicating with an electrocoagulation chamber installed therein. The electrocoagulation chamber is made in the form of a tube accomodating a system of soluble electrodes arranged in the bottom portion thereof. Contaminated liquid is fed into the electrocoagulation chamber through an inlet pipe mounted above the system of the electrodes.
The apparatus is also provided with a device for remov-ing foam, which device is made in the form of a pipe-line having a bell-shaped opening at one end thereof arranged above the electrocoagulation chamber. The other open end of the pipeline is open and communicates with a pipe for discharging waste.
A disadvantage of the apparatus under consider-ation resides in that a part of foam passes into the top portion of the settling chamber through a space between the bell-shaped opening and electrocoagulation chamber. Under continuous operation, a considerable B
amount of foam accumulates in this portion of the apparatus, thereby leading to a formation of a layer of a compact foam which gradually settles down in the settling chamber. This makes it necessary to accom-plish frequent maintenance treatments of the apparatusto remove the compacted foam from the settling chamber, which considerably reduces the efficiency of the appar-atus. Thus, in an apparatus with a purification rate of 6 m per hour such treatments take 10 to 15 min per 1.5 to 2 hours of the -apparatus operation.
Also, there takes place a partial precipitation of the aggregates of contaminants. These aggregates are entrained by a flow of the purified liquid and carried to the outlet pipe, which adversely affects the quality and stability of the purification process.
The foam being formed is characterized by a high thermodynamic stability which amounts to 3 to 5 hours. Since the volume of the foam is 5 to 10 times as high as the volume of the contaminated liquid being treated, the latter is to be delivered to big vessels wherein the foam will be spontaneously extinguished, or special means (mechanical, chemical and others), for extinguishing the foam should be taken advantage of.
The object of the invention is to provide an apparatus for electrochemical purification of contam-inated liquids, wherein a device for removing foam is constructed so as to prevent compaction of foam by continuously removing it from settling chamber and thereby to improve the stability of the purification process and to upgrade the efficiency of the apparatus as well as to reduce the specific expenditures required for the operation of the apparatus.
.
1~7290 The principal object of the present invention is to provide an apparatus for electrochemical purif-ication of contaminated liquids, wherein a device for , removing foam is constructed so as to allow foam to be opportunately removed from a settling chamber without ' stopping the apparatus.
- Another object of the invention is to improve the stability of the purification process.
; Still another object of the invention is to upgrade the efficiency of the apparatus.
' In accordance with a particular embodiment of the invention there is provided an apparatus for electro-chamical purification of contaminated liquids. m e apparatus includes a settling chamber having an outlet pipe for discharging purified liquid and an outlet pipe for discharging waste. Means are provided for defining an outlet for removing foam from the apparatus. An electrocoagulation chamber is installed in the settling chamber and communicates therewith and has an inlet pipe for feeding contaminated liquid and an inlet pipe - for feeding electrolyte. A system of soluble electrodes is installed in the bottom portion of the electrocoagu-lation chamber below the inlet pipe for feeding contam-inated liquid. A device is provided for removing formed foam from the apparatus, the device having a pipeline for transferring from outside the settling chamber, the pipeline being rotatable in a horizontal plane and provided with a bell-shaped opening for drawing foam from the settling chamber, the pipeline being arranged substantially above the settling chamber and having one open end communicating with the outlet pipe for removing foam from the apparatus. The device for removing foam ,~
~7Z'~O
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further includes an air injector installed within the pipeline for drawing foam into the bell-shaped opening and transferring it through the pipeline to the open end thereof.
In accordance with a further embodiment of the invention there is provided an apparatus for con-tinuous electrochemical purification in contaminated liquids. The apparatus includes an electrocoagulation chamber for containing an electrolyte and having sol-uble electrodes therein. Means are provided to intro-duce the electrolyte into the electrocoagulation cham-ber, and means are provided to introduce contaminated ; liquid into the electrocoagulation chamber while it contains the electrolyte. The electrocoagulation - 15 chamber is open at the top. A settling chamber is disposed circumferentially about the electrocoagulation - chamber for receiving liquid from the electrocoagulation chamber after treatment of the contaminated liquid to coagulate impurities therein. A discharge conduit is disposed above the level of the bottom of the settling chamber to discharge purified liquids from the settling chamber. Also provided is a suction type foam removing ejector comprising a suction opening above the level of the electrocoagulation chamber for removing foam from liquid discharge from the electrocoagulation chamber.
The above arrangement of the apparatus pro-vides for continuous removal of foam from the settling chamber, the foam flows thereinto from the electro-coagulation chamber. As a result, the foam does not accumulate in the settling chamber. Even heavy fractions of the contaminants are sucked into the bell-shaped opening to be removed from the apparatus. As a L~
~147'~90 . .
consequence, the purification process becomes more stable, and the recurrent preventive treatments of the apparatus are not needed, as distinct from the prior art apparatus wherein such treatments are carried out to remove the foam accumulated in the settling chamber.
It is advisable that an insertion piece shaped as a hydraulic screw be provided within the pipeline to transfer foam outside the settling chamber.
Such an insertion piece makes it possible to intensify -~ 10 the friction of the foam against the pipeline walls and causes the same foam to divide into such components as oil, water, and air, thereby decreasing the volume of the foam with respect to the liquid products being removed therewith.
It is further advisable that the apparatus be provided with a foam level controller whose sensor is installed in the settling chamber and final control element controls the supply of air into the air injector, depending on the foam level.
The above foam level controller allows the power consumption required for removing foam to be considerably reduced, since, in this case, the air injector is energized only when the foam has accumulated in a sufficient quantity within the settling chamber.
By appropriately adjusting such a controller the power consumption for removing the foam can be reduced to a minimum, while retaining the required stability of the purification process.
The exact nature of this invention will be readily apparent from consideration of the following specification relating to the annexed drawing in which:
11~72~
Fig. 1 i3 a vertical elevation cross-section view of the apparatus for electrochemical purification of contaminated liquids, according to the invention, Fig. 2 is a fragmentary elevation cross-section view of an alternative modification of thedevice for removing foam, Fig. 3 is a fragmentary elevation view of an alternative modification of the apparatus of the present invention, allowing for a reduction of power consumption required for removing foam.
Reference is now made to Fig. 1 showing an apparatus for purification of contaminated liquids comprising a cylindrical settling chamber 1 which houses an electrocoagulation chamber 2 installed co-axially therewith and made in the form of a tube.Between the chambers 1 and 2, there is an annular settling zone defined by the walls of the two chambers.
The settling chamber 1 has an outlet pipe 3 for dis~
charging purified liquid, disposed at its top portion and an outlet pipe 4 for discharging waste, disposed in its lower portion.
A t~bular partition 5 is installed in the annular settling zone to increase the path of travel for purified liquid to pass within the settling chamber 1. In the upper portion of the apparatus there is an annular chute 6 which bridges over the space between the walls of the settling chamber 1 and the tubular partition 5 and is arranged below an upper edge of the partition 5 and an upper open end of the electrocoagul-ation chamber 2. Disposed above the chute 6 there is -~ a pipe or conduit 7 for removing foam.
-B
~7290 In the lower portion of the electrocoagulation chamber 2 there is arranged a system 8 of soluble electrodes, some of these electrodes are connected to a positive terminal 9 of a direct current source (not shown) and the rest of them, to a negative terminal 10 of this source. An inlet pipe 11 for feeding contamin-ated liquid into the electrocoagulation chamber 2 is located above this systém of electrodes.
A foam removing device 12 for removing foam from liquid comprises a pipeline 13 secured in its ~ middle-portion to a pivoting support 14 mounted in a cover 15 of the settling chamber 1. The above pivoting support 14 is constructed in a conventional manner and is set in rotation by an electromotor (not shown); it has passages 16, 17 and 18 for compressed air to pass therethrough into the air injector 19 installed in the pipeline 13. This pipeline has a bell-shaped opening 20 disposed above the settling chamber 1 and a bent open end disposed above the annular chute 6. The air injector 19 and the bell-shaped opening 20 are mutually arranged so that when compressed air is supplied to the air injector 19, the foam is sucked into the bell-shaped opening 20 and then transferred through the pipeline 13 to the open end thereof.
Fig. 2 shows an alternative embodiment of the invention, wherein the partition 5 is made shorter so that its upper portion forms together with the annular chute 6 a flange of a L-shaped configuration in cross-section.
To feed electrolyte into the electrocoagulation chamber 2, an inlet pipe 21 is provided, this pipe is disposed under the system8 of soluble electrodes.
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To provide for a more efficient removal of foam by way of decreasing its cubical content in a foam condensate, an insertion piece 22 (Fig. 2) made in the form of a hydraulic screw may be installed within the pipeline 13.
To reduce the power consumption required for removing foam, the apparatus may be provided with a foam level controller 23 (Fig. 3) whose sensor 24 is installed in the settling chamber 1 and final control element, such as electromagnetic valve 25 is connected to a pipeline 26 for supplying compressed air into the air injector 19.
The apparatus operates in the following way.
Before treating contaminated liquid, the electrocoagulation chamber is filled with pure electro-lyte (industrial water containing small additives of HCl and NaCl), whereupon the system 8 of electrodes is energized, and, after some interval (25-30 sec), contaminated liquid is fed into the apparatus through the inlet pipe 11. This liquid fills the electrocoagu-lation chamber 2.
In the course of the anodic dissolution of the soluble electrodes, there are formed metal hydroxides which float up together with bubbles of gas (hydrogen and oxygen). The metal hydroxides coagulate the colloid - contaminants contained in the liquid into aggregates.
Further, these aggregates are carried up by the gas bubbles up the electrocoagulation chamber.
Thus treated liquid passes together with the aggregates contained therein into the chamber 1 where it separates into layers of oil, foam, and pure liquid.
Under the action of injection, the foam passes into B
114~72~0 the pipeline 13. While passing through this pipeline the foam separates into oil and water and then passes to the chute 6 and therefrom into the outlet pipe 7. As the pipeline 12 rotates, the bell-shapea opening 20 draws in the foam from the settling chamber 1. The air jet from the injector 19 impinges on the foam and thus breaks up the bubbles and decreases the volume thereof.
Thereafter, this valuable condensate is settled in separate vessels. The purified liquid is discharged through the outlet pipe 3. The sludge accumulated in the settling chamber 1 is discharged through the outlet pipe 4, constituting a helical screw or hydraulic screw.
With the insertion piece 22 (Fig 2) installed in the pipeline 13, the foam passing through the pipe-line 13 rotates. Due to the friction of the foam against the walls of the pipeline 13 and the screw sur-face of the insertion piece 22 the process of breaking up the bubbles of the foam and separation thereof into oil and water intensifies, the oil and water passing, as indicated above, to the annular chute 6.
The products of the foam of reducea volume are directed into a separate vessei to settle.
The apparatus of the present invention may be provided with a foam level controller 23 (Fig. 3).
As soon as the foam level in the settling chamber 1 reaches the predetermined limit the sensor 24 of the foam level controller 23 operates and the latter by means of the valve 25 connects a source of compressed air (not shown) to the air injector 19. As the foam level in the settling chamber 1 lowers below the Z~30 predetermined limit, the sensor 24 produces a corres-ponding signal to the foam level controller 23 which disconnects the source of the compressed air from the air injector 19.
Tests of the apparatus of the present invention have shown high reliability of the apparatus in operation the consum~tion of labour for maintanence of the appar-atus has decreased, on average, by 8 to 10%. Removal of foam from the apparatus requires no additional main-tanence.
The screw-shaped insertion piece installed within the pipeline ensures high efficiency in extinguish-ing the formed foam: the volume content of foam in the condensate has decreased by 15 to 20 times and is not more than 0.15 of the volume in the liquid conden-sate. Hence, the foam condensate does not require any further treatment.
The foam level control allows the power con-sumption for removing foam to be greatly reduced. Thus, ~ 20 tests of the apparatus of the present invention have shown that in purifying spent cutting fluids containing impurities in an amount of 1600 to 3200 mg/l the con-sumption of compressed air is 2.7 to 3.0 times lower.
The above embodiments of the present invention - 25 are given for illustration purposes only. It will be understood by those skilled in the art that the invention may be variously otherwise embodied within the scope of the appended claims.
B
The invention may be imployed for purifying liquids contaminated with organic substances, mechanical ! suspensions, surfactants, and the like.
The invention is particularly useful for pur-ifying liquids contaminated with petroleum products, such as waste waters containing oils and greases.
Apparatus for electrochemical purification of liquids, in particular those where liquid is pur-ified by electroflotation and electrocoagulation method~, have recently found ever increasing application owing to their high performance capabilities.
Known in the art are apparatus for electro-chemical purification of liquids is accomplished either periodically, i.e. in batches, or continuously, the latter apparatus seem to be more promising.
There is also known an apparatus for electro-chemical purification of contaminated liquids compris-ing a settling chamber housing an electrocoagulation chamber installed coaxially therewith, a system of soluble electrodes in the latter chamber, an inlet pipe for discharging purified liquid, and a device for re-moving foam from the apparatus (see, for instance, U.S.
Patent No. 3,505,188).
The device for removing foam from the above apparatus may take the form of a rotatable scraper mounted in the top portion of the settling chamber, or of a conveyor belt provided with paddles secured thereto.
B
1147Z~30 With such a structural arrangement of the device, a part of heavy fractions of the foam (free coagulants of electrode metal hydroxides, particles of contaminants etc.) are thrown with the scraper into the liquid contained within the settling chamber. If this settling chamber is not high enough, the above fractions are entrained by the liquid flow and carried into the pipe for discharging purified liquid, which adversely affects the efficiency of the purification process.
There is known an apparaLus or electro-chemical purification of contaminated liquids described in USSR Inventor's Certificate No. 644,738 granted to Nazaryan et al, October 6, 1978~ and comprising a settling chamber having outlet pipes for discharging purified liquid and waste and communicating with an electrocoagulation chamber installed therein. The electrocoagulation chamber is made in the form of a tube accomodating a system of soluble electrodes arranged in the bottom portion thereof. Contaminated liquid is fed into the electrocoagulation chamber through an inlet pipe mounted above the system of the electrodes.
The apparatus is also provided with a device for remov-ing foam, which device is made in the form of a pipe-line having a bell-shaped opening at one end thereof arranged above the electrocoagulation chamber. The other open end of the pipeline is open and communicates with a pipe for discharging waste.
A disadvantage of the apparatus under consider-ation resides in that a part of foam passes into the top portion of the settling chamber through a space between the bell-shaped opening and electrocoagulation chamber. Under continuous operation, a considerable B
amount of foam accumulates in this portion of the apparatus, thereby leading to a formation of a layer of a compact foam which gradually settles down in the settling chamber. This makes it necessary to accom-plish frequent maintenance treatments of the apparatusto remove the compacted foam from the settling chamber, which considerably reduces the efficiency of the appar-atus. Thus, in an apparatus with a purification rate of 6 m per hour such treatments take 10 to 15 min per 1.5 to 2 hours of the -apparatus operation.
Also, there takes place a partial precipitation of the aggregates of contaminants. These aggregates are entrained by a flow of the purified liquid and carried to the outlet pipe, which adversely affects the quality and stability of the purification process.
The foam being formed is characterized by a high thermodynamic stability which amounts to 3 to 5 hours. Since the volume of the foam is 5 to 10 times as high as the volume of the contaminated liquid being treated, the latter is to be delivered to big vessels wherein the foam will be spontaneously extinguished, or special means (mechanical, chemical and others), for extinguishing the foam should be taken advantage of.
The object of the invention is to provide an apparatus for electrochemical purification of contam-inated liquids, wherein a device for removing foam is constructed so as to prevent compaction of foam by continuously removing it from settling chamber and thereby to improve the stability of the purification process and to upgrade the efficiency of the apparatus as well as to reduce the specific expenditures required for the operation of the apparatus.
.
1~7290 The principal object of the present invention is to provide an apparatus for electrochemical purif-ication of contaminated liquids, wherein a device for , removing foam is constructed so as to allow foam to be opportunately removed from a settling chamber without ' stopping the apparatus.
- Another object of the invention is to improve the stability of the purification process.
; Still another object of the invention is to upgrade the efficiency of the apparatus.
' In accordance with a particular embodiment of the invention there is provided an apparatus for electro-chamical purification of contaminated liquids. m e apparatus includes a settling chamber having an outlet pipe for discharging purified liquid and an outlet pipe for discharging waste. Means are provided for defining an outlet for removing foam from the apparatus. An electrocoagulation chamber is installed in the settling chamber and communicates therewith and has an inlet pipe for feeding contaminated liquid and an inlet pipe - for feeding electrolyte. A system of soluble electrodes is installed in the bottom portion of the electrocoagu-lation chamber below the inlet pipe for feeding contam-inated liquid. A device is provided for removing formed foam from the apparatus, the device having a pipeline for transferring from outside the settling chamber, the pipeline being rotatable in a horizontal plane and provided with a bell-shaped opening for drawing foam from the settling chamber, the pipeline being arranged substantially above the settling chamber and having one open end communicating with the outlet pipe for removing foam from the apparatus. The device for removing foam ,~
~7Z'~O
:;
:
further includes an air injector installed within the pipeline for drawing foam into the bell-shaped opening and transferring it through the pipeline to the open end thereof.
In accordance with a further embodiment of the invention there is provided an apparatus for con-tinuous electrochemical purification in contaminated liquids. The apparatus includes an electrocoagulation chamber for containing an electrolyte and having sol-uble electrodes therein. Means are provided to intro-duce the electrolyte into the electrocoagulation cham-ber, and means are provided to introduce contaminated ; liquid into the electrocoagulation chamber while it contains the electrolyte. The electrocoagulation - 15 chamber is open at the top. A settling chamber is disposed circumferentially about the electrocoagulation - chamber for receiving liquid from the electrocoagulation chamber after treatment of the contaminated liquid to coagulate impurities therein. A discharge conduit is disposed above the level of the bottom of the settling chamber to discharge purified liquids from the settling chamber. Also provided is a suction type foam removing ejector comprising a suction opening above the level of the electrocoagulation chamber for removing foam from liquid discharge from the electrocoagulation chamber.
The above arrangement of the apparatus pro-vides for continuous removal of foam from the settling chamber, the foam flows thereinto from the electro-coagulation chamber. As a result, the foam does not accumulate in the settling chamber. Even heavy fractions of the contaminants are sucked into the bell-shaped opening to be removed from the apparatus. As a L~
~147'~90 . .
consequence, the purification process becomes more stable, and the recurrent preventive treatments of the apparatus are not needed, as distinct from the prior art apparatus wherein such treatments are carried out to remove the foam accumulated in the settling chamber.
It is advisable that an insertion piece shaped as a hydraulic screw be provided within the pipeline to transfer foam outside the settling chamber.
Such an insertion piece makes it possible to intensify -~ 10 the friction of the foam against the pipeline walls and causes the same foam to divide into such components as oil, water, and air, thereby decreasing the volume of the foam with respect to the liquid products being removed therewith.
It is further advisable that the apparatus be provided with a foam level controller whose sensor is installed in the settling chamber and final control element controls the supply of air into the air injector, depending on the foam level.
The above foam level controller allows the power consumption required for removing foam to be considerably reduced, since, in this case, the air injector is energized only when the foam has accumulated in a sufficient quantity within the settling chamber.
By appropriately adjusting such a controller the power consumption for removing the foam can be reduced to a minimum, while retaining the required stability of the purification process.
The exact nature of this invention will be readily apparent from consideration of the following specification relating to the annexed drawing in which:
11~72~
Fig. 1 i3 a vertical elevation cross-section view of the apparatus for electrochemical purification of contaminated liquids, according to the invention, Fig. 2 is a fragmentary elevation cross-section view of an alternative modification of thedevice for removing foam, Fig. 3 is a fragmentary elevation view of an alternative modification of the apparatus of the present invention, allowing for a reduction of power consumption required for removing foam.
Reference is now made to Fig. 1 showing an apparatus for purification of contaminated liquids comprising a cylindrical settling chamber 1 which houses an electrocoagulation chamber 2 installed co-axially therewith and made in the form of a tube.Between the chambers 1 and 2, there is an annular settling zone defined by the walls of the two chambers.
The settling chamber 1 has an outlet pipe 3 for dis~
charging purified liquid, disposed at its top portion and an outlet pipe 4 for discharging waste, disposed in its lower portion.
A t~bular partition 5 is installed in the annular settling zone to increase the path of travel for purified liquid to pass within the settling chamber 1. In the upper portion of the apparatus there is an annular chute 6 which bridges over the space between the walls of the settling chamber 1 and the tubular partition 5 and is arranged below an upper edge of the partition 5 and an upper open end of the electrocoagul-ation chamber 2. Disposed above the chute 6 there is -~ a pipe or conduit 7 for removing foam.
-B
~7290 In the lower portion of the electrocoagulation chamber 2 there is arranged a system 8 of soluble electrodes, some of these electrodes are connected to a positive terminal 9 of a direct current source (not shown) and the rest of them, to a negative terminal 10 of this source. An inlet pipe 11 for feeding contamin-ated liquid into the electrocoagulation chamber 2 is located above this systém of electrodes.
A foam removing device 12 for removing foam from liquid comprises a pipeline 13 secured in its ~ middle-portion to a pivoting support 14 mounted in a cover 15 of the settling chamber 1. The above pivoting support 14 is constructed in a conventional manner and is set in rotation by an electromotor (not shown); it has passages 16, 17 and 18 for compressed air to pass therethrough into the air injector 19 installed in the pipeline 13. This pipeline has a bell-shaped opening 20 disposed above the settling chamber 1 and a bent open end disposed above the annular chute 6. The air injector 19 and the bell-shaped opening 20 are mutually arranged so that when compressed air is supplied to the air injector 19, the foam is sucked into the bell-shaped opening 20 and then transferred through the pipeline 13 to the open end thereof.
Fig. 2 shows an alternative embodiment of the invention, wherein the partition 5 is made shorter so that its upper portion forms together with the annular chute 6 a flange of a L-shaped configuration in cross-section.
To feed electrolyte into the electrocoagulation chamber 2, an inlet pipe 21 is provided, this pipe is disposed under the system8 of soluble electrodes.
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To provide for a more efficient removal of foam by way of decreasing its cubical content in a foam condensate, an insertion piece 22 (Fig. 2) made in the form of a hydraulic screw may be installed within the pipeline 13.
To reduce the power consumption required for removing foam, the apparatus may be provided with a foam level controller 23 (Fig. 3) whose sensor 24 is installed in the settling chamber 1 and final control element, such as electromagnetic valve 25 is connected to a pipeline 26 for supplying compressed air into the air injector 19.
The apparatus operates in the following way.
Before treating contaminated liquid, the electrocoagulation chamber is filled with pure electro-lyte (industrial water containing small additives of HCl and NaCl), whereupon the system 8 of electrodes is energized, and, after some interval (25-30 sec), contaminated liquid is fed into the apparatus through the inlet pipe 11. This liquid fills the electrocoagu-lation chamber 2.
In the course of the anodic dissolution of the soluble electrodes, there are formed metal hydroxides which float up together with bubbles of gas (hydrogen and oxygen). The metal hydroxides coagulate the colloid - contaminants contained in the liquid into aggregates.
Further, these aggregates are carried up by the gas bubbles up the electrocoagulation chamber.
Thus treated liquid passes together with the aggregates contained therein into the chamber 1 where it separates into layers of oil, foam, and pure liquid.
Under the action of injection, the foam passes into B
114~72~0 the pipeline 13. While passing through this pipeline the foam separates into oil and water and then passes to the chute 6 and therefrom into the outlet pipe 7. As the pipeline 12 rotates, the bell-shapea opening 20 draws in the foam from the settling chamber 1. The air jet from the injector 19 impinges on the foam and thus breaks up the bubbles and decreases the volume thereof.
Thereafter, this valuable condensate is settled in separate vessels. The purified liquid is discharged through the outlet pipe 3. The sludge accumulated in the settling chamber 1 is discharged through the outlet pipe 4, constituting a helical screw or hydraulic screw.
With the insertion piece 22 (Fig 2) installed in the pipeline 13, the foam passing through the pipe-line 13 rotates. Due to the friction of the foam against the walls of the pipeline 13 and the screw sur-face of the insertion piece 22 the process of breaking up the bubbles of the foam and separation thereof into oil and water intensifies, the oil and water passing, as indicated above, to the annular chute 6.
The products of the foam of reducea volume are directed into a separate vessei to settle.
The apparatus of the present invention may be provided with a foam level controller 23 (Fig. 3).
As soon as the foam level in the settling chamber 1 reaches the predetermined limit the sensor 24 of the foam level controller 23 operates and the latter by means of the valve 25 connects a source of compressed air (not shown) to the air injector 19. As the foam level in the settling chamber 1 lowers below the Z~30 predetermined limit, the sensor 24 produces a corres-ponding signal to the foam level controller 23 which disconnects the source of the compressed air from the air injector 19.
Tests of the apparatus of the present invention have shown high reliability of the apparatus in operation the consum~tion of labour for maintanence of the appar-atus has decreased, on average, by 8 to 10%. Removal of foam from the apparatus requires no additional main-tanence.
The screw-shaped insertion piece installed within the pipeline ensures high efficiency in extinguish-ing the formed foam: the volume content of foam in the condensate has decreased by 15 to 20 times and is not more than 0.15 of the volume in the liquid conden-sate. Hence, the foam condensate does not require any further treatment.
The foam level control allows the power con-sumption for removing foam to be greatly reduced. Thus, ~ 20 tests of the apparatus of the present invention have shown that in purifying spent cutting fluids containing impurities in an amount of 1600 to 3200 mg/l the con-sumption of compressed air is 2.7 to 3.0 times lower.
The above embodiments of the present invention - 25 are given for illustration purposes only. It will be understood by those skilled in the art that the invention may be variously otherwise embodied within the scope of the appended claims.
B
Claims (16)
1. An apparatus for electrochemical purifica-tion of contaminated liquids comprising:
a settling chamber having an outlet pipe for discharging purified liquid and an outlet pipe for dis-charging waste;
means for defining an outlet for removing foam from the apparatus;
an electrocoagulation chamber installed in said settling chamber, communicating therewith, and having an inlet pipe for feeding contaminated liquid and an inlet pipe for feeding electrolyte;
a system of soluble electrodes installed in the bottom portion of said electrocoagulation chamber below the inlet pipe for feeding contaminated liquid;
a device for removing formed foam from the apparatus, said device having a pipeline for trans-ferring from outside the settling chamber, said pipeline being rotatable in a horizontal plane, provided with a bell-shaped opening for drawing foam from the settl-ing chamber, arranged substantially above said settling chamber and having one open end communicating with said outlet for removing foam from the apparatus, said device for removing foam further including an air injector, installed within said pipeline for drawing foam into the bell-shaped opening and transferring it through the pipeline to the open end thereof.
a settling chamber having an outlet pipe for discharging purified liquid and an outlet pipe for dis-charging waste;
means for defining an outlet for removing foam from the apparatus;
an electrocoagulation chamber installed in said settling chamber, communicating therewith, and having an inlet pipe for feeding contaminated liquid and an inlet pipe for feeding electrolyte;
a system of soluble electrodes installed in the bottom portion of said electrocoagulation chamber below the inlet pipe for feeding contaminated liquid;
a device for removing formed foam from the apparatus, said device having a pipeline for trans-ferring from outside the settling chamber, said pipeline being rotatable in a horizontal plane, provided with a bell-shaped opening for drawing foam from the settl-ing chamber, arranged substantially above said settling chamber and having one open end communicating with said outlet for removing foam from the apparatus, said device for removing foam further including an air injector, installed within said pipeline for drawing foam into the bell-shaped opening and transferring it through the pipeline to the open end thereof.
2. An apparatus as claimed in claim 1, further comprising an insertion piece installed within said pipeline for transferring foam therethrough and shaped as a hydraulic screw.
3. An apparatus as claimed in claim 1 or 2 further comprising a foam level controller having a sensor installed within the settling chamber and a final control element to control the supply of air into the air injector, depending on the foam level.
4 Apparatus for continuous electrochemical purification of contaminated liquids comprising, an electrocoagulation chamber for containing an electrolyte and having soluble electrodes therein, means to intro-duce said electrolyte into said electrocoagulation chamber, means to introduce contaminated liquid into said electrocoagulation chamber while it contains said electrolyte, said electrocoagulation chamber being open at the top, a settling chamber disposed circumferentially about said electrocoagulation chamber for receiving liquid from the electrocoagulation chamber after treat-ment of the contaminated liquid to coagulate impurities therein, a discharge conduit above the level of the bottom of the settling chamber to discharge purified liquid from the settling chamber, and a suction type foam-removing ejector comprising a suction opening above the level of said electrocoagulation chamber for removing foam from liquid discharged from the electro-coagulation chamber.
5. Apparatus for continuous electrochemical pur-ification of contaminated liquids according to claim 4, in which said foam-removing ejector suction opening comprises a bell-shaped opening above the level of said settling tank, a discharge conduit in communication with said bell-shaped opening for discharging outwardly of said apparatus foam collected by said foam-removing ejector.
.
.
6. Apparatus for continuous electrochemical purification of contaminated liquids according to claim 5, in which said ejector comprises an air injector for introducing air into said ejector for drawing said foam into the ejector through said bell-shaped opening.
7. Apparatus for continuous electrochemical pur-ification of contaminated liquids according to claim 4, a tubular partition disposed in said settling chamber spaced from outer surfaces of walls of the electro-coagulation chamber and inner surfaces of walls of the settling chamber and spaced upwardly from the bottom of the settling chamber thereby defining an annular space circumferentially of the electrocoagulation cham-ber into which liquid treated in the electrocoagulation chamber spills over the upper open end of the electro-coagulation chamber, and said bell-shaped opening of said foam-removing ejector being disposed directly over the annular space.
8. Apparatus for continuous electrochemical pur-ification of contaminated liquids according to claim 4, in which said foam-removing ejector is pivotally mounted for rotation along a path about the electro-coagulation chamber, and pivot means pivotally mounting said ejector.
9. Apparatus for continuous electrochemical purification of contaminated liquids according to claim 8, including means for selectively rotating said ejector on said pivot means.
10. Apparatus for continuous electrochemical pur-ification of contaminated liquids according to claim 4, a tubular partition disposed in said settling chamber spaced from outer surfaces of walls of the electro-coagulation chamber and inner surfaces of walls of the settling chamber and spaced upwardly from the bottom of the settling chamber thereby defining an annular space circumferentially of the electrocoagulation chamber into which liquid treated in the electrocoagulation chamber spills over the upper open end of the electro-coagulation chamber, and a bridge between outer walls of the settling chamber and said partition for support-ing foam thereon.
11. Apparatus for continuous electrochemical purification of contaminated liquids according to claim 4, including control means for automatically controlling the level of the foam.
12. Apparatus for continuous electrochemical pur-ification of contaminated liquids according to claim 11, in which said control means comprises sensor means sensing the level of the foam to control removal of foam by said ejector.
13. Apparatus for continuous electrochemical pur-ification of contaminated liquids according to claim 12, in which said foam-removing ejector comprises an air injector for supply of air under pressure into said ejector, and said control means including means to automatically control supply of said air.
14. Apparatus for continuous electrochemical pur-ification of contaminated liquids according to claim 4, including means to break the bubbles in the foam in said ejector to extract the foam as liquid therefrom.
15. Apparatus for continuous electrochemical pur-ification of contaminated liquids according to claim 14, in which said means to break up the bubbles in-cludes a driven helical screw in said ejector.
16. Apparatus for continuous electrochemical purification of contaminated liquids according to claim 4, in which said foam-removing injector comprises an air injector delivering air under pressure into said ejector effective to break up bubbles in the foam and reduce the volume thereof.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SU2740571 | 1979-03-26 | ||
| SU2740571 | 1979-03-26 | ||
| SU2787088 | 1979-07-02 | ||
| SU2787088 | 1979-07-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1147290A true CA1147290A (en) | 1983-05-31 |
Family
ID=26665768
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000348358A Expired CA1147290A (en) | 1979-03-26 | 1980-03-25 | Apparatus for electrochemical purification of contaminated liquids |
Country Status (3)
| Country | Link |
|---|---|
| CA (1) | CA1147290A (en) |
| DE (1) | DE3011691C2 (en) |
| FR (1) | FR2452305A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012024759A1 (en) * | 2010-08-25 | 2012-03-01 | Boydel Wastewater Technlogies Inc. | Wastewater treatment apparatus and method |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1986001124A1 (en) * | 1984-08-11 | 1986-02-27 | Edgar Renzler | Process for the separation of emulsions containing water as a continuous phase and device for the application of the process |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR873952A (en) * | 1941-06-26 | 1942-07-31 | ||
| NL253723A (en) * | 1960-02-08 | |||
| US3505188A (en) * | 1965-06-18 | 1970-04-07 | Fairbanks Morse Inc | Electrolytic flotation method and apparatus |
| US3512453A (en) * | 1968-05-22 | 1970-05-19 | Caterpillar Tractor Co | System for actuation of hydraulic motors on tractor powered implements |
| AU455172B2 (en) * | 1969-04-08 | 1974-11-01 | Shelley King Arthur | Fluid treatment system with cooling means |
| FR2228037A1 (en) * | 1973-05-02 | 1974-11-29 | Mitsubishi Electric Corp | Electrolytic purificn of sewage water and effluents - by flocculation, maintaining a narrow gap between the electrode faces |
| CH594570A5 (en) * | 1976-09-15 | 1978-01-13 | Bbc Brown Boveri & Cie | |
| DE2644650C3 (en) * | 1976-10-02 | 1979-10-04 | Rolf 3061 Buchholz Hilker | Teaching about building gable walls in the roof area |
| DE2657319A1 (en) * | 1976-12-17 | 1978-06-29 | Sachs Systemtechnik Gmbh | Anodic oxidation fluid purifying equipment - has auxiliary electrodes as circular plates rotating on common axis in packet |
| SU644738A1 (en) * | 1977-08-23 | 1979-01-30 | Харьковский Ордена Ленина И Ордена Октябрьской Революции Моторостроительный Завод "Серп И Молот" | Apparatus for electrochemical purification of waste water |
-
1980
- 1980-03-25 CA CA000348358A patent/CA1147290A/en not_active Expired
- 1980-03-26 DE DE3011691A patent/DE3011691C2/en not_active Expired
- 1980-03-26 FR FR8006768A patent/FR2452305A1/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012024759A1 (en) * | 2010-08-25 | 2012-03-01 | Boydel Wastewater Technlogies Inc. | Wastewater treatment apparatus and method |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2452305A1 (en) | 1980-10-24 |
| FR2452305B1 (en) | 1982-12-10 |
| DE3011691C2 (en) | 1983-11-03 |
| DE3011691A1 (en) | 1980-10-09 |
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