CA1232570A - Apparatus for electrochemical purification of contaminated liquids - Google Patents
Apparatus for electrochemical purification of contaminated liquidsInfo
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- CA1232570A CA1232570A CA000455856A CA455856A CA1232570A CA 1232570 A CA1232570 A CA 1232570A CA 000455856 A CA000455856 A CA 000455856A CA 455856 A CA455856 A CA 455856A CA 1232570 A CA1232570 A CA 1232570A
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Abstract
APPARATUS FOR ELECTROCHEMICAL
PURIFICATION OF CONTAMINATED LIQUIDS
Abstract An apparatus is proposed for electrochemical purifi-cation of contaminated liquids which comprises a settling chamber with outlet pipes for discharging the purified li-quid and wastes separated in the course of purification, this settling chamber partially embracing a coagulation chamber disposed coaxially therein and underlying a froth collector, the lower portion of the chamber accommodating an inlet pipe for feeding an electrolyte and consumable electrodes above which there is secured a mixer with pipes for supplying contaminated liquid thereinto, and a sepa-rating wall interposed between the settling chamber and coagulation chamber. A section of the coagulation chamber accommodated in the settling chamber and the separating wall are fashioned as truncated cones facing by their large bases the froth collector, the mixing chamber hav-ing perforated damping partitions.
PURIFICATION OF CONTAMINATED LIQUIDS
Abstract An apparatus is proposed for electrochemical purifi-cation of contaminated liquids which comprises a settling chamber with outlet pipes for discharging the purified li-quid and wastes separated in the course of purification, this settling chamber partially embracing a coagulation chamber disposed coaxially therein and underlying a froth collector, the lower portion of the chamber accommodating an inlet pipe for feeding an electrolyte and consumable electrodes above which there is secured a mixer with pipes for supplying contaminated liquid thereinto, and a sepa-rating wall interposed between the settling chamber and coagulation chamber. A section of the coagulation chamber accommodated in the settling chamber and the separating wall are fashioned as truncated cones facing by their large bases the froth collector, the mixing chamber hav-ing perforated damping partitions.
Description
~32ti~0 APPARAI~S FOR ELECTROCHEMICA~
PVRIFICATION OF CONTAMINATED LIQUIDS
his invention relate generally to the art of li-quid purification, and more particularly to an apparatus for electrochemical purification of contaminated liquids.
The device according to the invention can find ap-plication for purifying liquids contaminated by various impurities nonsoluble in water, such as organic matter, solid suspensions, and the like.
The apparatus of the invention may be utilized with the utmost advantage for purifying liquids polluted by petrolium products and polyrners, such as industrial sew-age containing oils and polymethyl methacrylates.
Among the presently known devices for purifying contaminated liquids an ever increasing use have found lately apparatuses for electrochemical purification of liquids due to their high process efficiency, particular-ly apparatuses capable of effecting electrocoagulation and electroflotation waste water treatment processes.
There are known apparatuses or carrying out elect-rochemical purification of contaminated liquids in in-termittent or in continuous modes of operation, the lat-ter appearing to be more promising.
One such apparatus for electrochemical purification of contaminated liquids comprises a settling chamber hav-ing outlet pipes for discharging the purified liquid and wastes wormed in the course of purification, this ~3~2S'~O
settling chamber partially embracing a coagulation chamb-er dieposed coaxially therein to underlie a froth collect-or, the bottom part of this chamber accommodating a pipe for feeding an electrolyte, and consumable electrodes above which there i9 disposed a mixer provided with an inlet pipe for supplying the contaminated liquid (cf., e.g., USSR Inventor's Certificate No. 644,738; IPC C
02F l/46, published 1979).
The coagulation chamber of this apparatus has an invariable cross-section in terms of height thereof.
In such a structural arrangement of the coagulation chamber wherein consolidation of the particles contained in the liquid being purified occur a certain constric-tion to the mOvement of aggregates of such particles tak-en place to result in partial breaking up of such parti-cles when they collide after being carried up by bubbles of gas emitted from the consumable electrodes.
This effects the efficiency of the apparatus, since for attaining the required degree of purification it it necessary to reduce the rate of feeding the contaminated liquid when the percentage of impurities contained there-in it increased, otherwise the split aggregates of impu-ritie~ vJill tend to be carried by the flow of purified liquid thereby affecting the quality of purification.
There it also known an apparatus for electrochemical purification of contaminated liquids (cf. USSR Inventor certificate No. 914,506; IPC C 02 l/46, published i982) comprising a settling chamber with outlet pipe for dip-~3~57(~
charging purified liquid and wastes communicable witha coagulation chamber arranged coaxially therein, the lover portion of this coagulation chamber accommodating an inlet pipe for feeding an electrolyte and a system of consumable electrodes and having a pipe for supplying a contaminated liquid to said chamber disposed abcve the consumable electrodes, and also a separating wall inter-posed between the settling chamber and the electrocoagu-lation chamber. Secured above the electrocoagulation cham-ber i8 a froth collector provided with an air injector for evacuating Roth waste from the apparatus.
The separating wall of this apparatua i9 cylindrical in shape and mounted in parallel with the walls of the electrocoagulation chamber. One more disadvantage of this construction is that the flow rate of the liquid being purified i6 maintained invariable in the zone confined by the separating wall and electrocoagulation chamber, which hampers an increase in the throughput capacity of the apparatus.
It is an object of this invention to provide an appa-ratus fox electrochemical purification of-contaminated liquids of such a construction as to prevent aggregates of particles formed during coagulation from being broken up .
In ac_ordance with the present nvention, there s thus provided an apparatus for electrochemical purification of contaminated liquids,comprising a settling chamber with ~;
~23;~S70 outlet pipes for discharging the purified liquid and wastes a coagulation chamber partially embraced by the settling chamber and arranged coaxially therewithi a froth collector provided wi-th an air injector mounted substantially above -the coagulation chamberi consumable electrodes arranged in the lower part of said coagulation chamberi an inlet pipe for feeding an electrolyte arranged in the bottom part of the coagulation chamber under said consumable electrodes; a mixer having an inlet pipe for supplying thereto a contaminated liquid and provided with perfo-rated damping partitions, the mixer being mounted inside the coagulatlon chamber above the consumable electrodes;
a separating wall interposed between the settling chamber and the coagulation chamber; part of the coagulation chamber disposed inside the settling chamber and the separating wall being in the form of truncated cones having upper larger bases and lower smaller bases with the larger bases facing the froth collector.
The aforedescribed arrangement provides more favour-able conditions for the impurities contained in the con-taminated liquid to coagulate by metal hydroxides produc-ed as a result of electrochemical dissolution of the ele-ctrodes in the pure electrolyte and carried to the mixer by the ascending flow. Constriction to the movement of the aggregates of impurities formed during coagulation and traveling upwards toward the liquid surface and their breaking up is prevented thanks to the disposition of the part of the coagulation chamber inside the settling chamb-.
~32S~7~
- 4a -er above the mixer and fashioning it as a truncated cone with the large base thereof facing the froth collector.
This advantageous effect is attained thanks to that the speed of the ascending flow of liquid tends to slow down , I, b ~3Z~i70 toward the liquid sur~aee due to the upwardly expanding cros~-sectional area of the coagulation chamber. Another attending advantage resides in the lack of excessive stir-ring of the particles of impurities being carried up which otherwise may split apart and affect the efficiency of the apparatus.
Preferably, the part of coagulation chamber disposed inside the settling chamber and fashioned a a truncated cone has a ratio between the area of it upper and lower bases within a range of 6.0 : 1Ø
Such an arrangement of the part of the eoagulation chamber in the form of a truncated cone with the above ra-tio between its upper and lower bases assures reduction in the speed of travel of the aseending flow of liquid to a value facilitating the formation of large aggregates of impurities, which tend to aecumulate at the suxface of the liquid under the froth collector to be evacuated the-refrom by~the air injector, makes the purification process 1.1 to i times more efficient. A further increase in this ratio leads to an increase in the amount of metal consumed for fabrication of the apparatus without adding tangibly effect to the efficiency thereof. Advisably, a filter is provided between the upper bates of the coagu-lation chamber and separating wall, vertical partition bein8 secured under the small base of the separating wall in the settling chamber, these vertical partitions over-lying outlet pipes for evacuating wastes tending to 3ettle down in the settling chamber:
~'~3~7(~
The provision of the filter enables to envigorate the process ox separation of the aggregates of impurities from the liquid, and consequently to increase the degree to which the contaminated liquid i8 purified and improve the efficiency of the apparatus.
The employment in the lower part of the settling chamber under the separating wall of vertical partitions makes it possible to slow down the speed of the flow of purified liquid pausing between the small baee ox the ye-parating wall and coagulation chamber, since the flow of liquid is passed through the spaces between said vertical partitions. This also promotes settling of the particles of impurities thanks to a sudden loss of the kinetic ener-gy of these impurities on the partitions, which again mak-es the apparatus more efficient and favours the purifica-tion process. As the wastes accumulate between the vertic-al partitions, they are periodically evacuated from the apparatus. These partitions may otherwise be inclined to the horizontal, depending on the type of the liquid being purified and on the presence of heterogeneous particles of impurities.
- Preferably, the perforated damping partitions secur-ed in the mixer are fashioned as cones with tops thereof facing the froth collector, a sprinkler being provided bet-ween the perforated damping paritions to assure a highly vigorous mixing of the contaminated liquid with the ascend-ing flow of the electrolyte.
The use of the perforated damping partitions in the ~3Z~70 mixer enables to envigorate mixing of the contaminated liquid with the electrolyte containing metal hydroxides and gas bubbles produced in the electrolyte in the course of electrochemical dissolution of the electrode. Such vigorous mixing facilitates the rate of coagulation of the particle of impurities through their interaction with the metal hydroxide. This i8 also promoted by the presence in the mixer of the sprinkler feeding the contaminated li-quid to the flow of the electrolyte. The sprinkler and the perforated damping partitions act to confine the area of mixing which is advantageous, since expansion of the mix-ing zone may result in breaking up of the coagulated ag-gregate~ of impurities. From the mixer the flow of treat-ed liquid escape through a hole in the upper damping par-tition~ which prevents a further stirring of the flows thereabove. Excessive stirring is also prevented thanks to that the section of the coagulation chamber overlying the mixer expand upwardly to slow down the speed of tra-vel of the liquid.
The conical upward pointing damping partitions pre-vent the accumulation in the mixer of gas and aggregates of impurities entrained by the ascending flow of liquid in the coagulation chamber. The provision of the zone of vigorous mixing of the contam1nated liquid with the as-cending flow of the electrolyte speeds up the rate of pu-rification and consequently results in increased through-put capacity of the apparatus.
The invention will now be dbscribed in greater ^de-~23257~
tail with reference to various specific embodiments there-of taken in conjunction with the accompanying drawings the sole Figure of which represents a general vieY~ of an apparatus for electrochemical purification of contaminat-ed liquids.
An apparatus for electrochemical purification of contaminated liquid according to the invention compri~e~
a settling chamber 1 having outlet pipes 2 and 3 for diæ-charging the purified liquid and wastes, respectively,this settling chamber 1 partially embracing a coagulation cham-ber 4 mounted coaxiall~ therein.
q`he lower section of the coagulation chamber 4 pro-jecting away from the settling chamber 1 accol~modate~ an inlet pipe 5 for feeding an electrolyte and con6umable ele-ctrodes 6. A mixer 7 with a pipe 8 for supplying a conta-minated liquid are arranged above the consumable elect-rodes 6. the mixer 7 is provided with perforated damping partitionæ 9 of conical configuration with tops of the cones pointing upwards. A sprinkler 10 is interposed bet-ween the damping partitions 9 to provide for vigorous mix-ing of the contaminated liquid supplied through the inlet pipe 8 with an ascending flow of electrolyte.
Part of the coagulation chamber 4 arranged coaxially inside the settling chamber 1 ha the form of a truncated cone 11 facing by its large base toward a froth collector 13, the ratio of this large baæe 12 to the small bate of the truncated cone making up this part of the coagulation chamber 4 being preferably 6.9~1Ø
~2325~0 The arrangement of the part of the chamber 4 in the form of a truncated cone with the above ratio between the surface areas of it large and small bases ensures a gra-dual reduction in the speed of the flow of liquid inside the chamber 4 to a value promoting the formation of large-size particles of impurities and preventing these parti-cles from breaking up due to reduced mixing of the system.
Di~po~ed between the settling ohamber 1 and the co-nical part of the coagulation chamber 4 it a separating wall 14 also having the form of a truncated cone with a large base 15 thereof facing the froth collector 13. The froth collector 13 i6 provided in its top part with an injector 16 serving to evacuate wastes formed of as Roth above the level of liquid in the coagulation chamber 4.
In order to envigorate the process of separating wastes from the liquid, a filter 17 it secured between the upp-er bases 12 and 15 of the coagulation chamber 4 and the eeparating wall 14, respectiYely, while under the ~epa-rating wall 14 there are arranged vertical partitions 18 and outlet pipes 19 for discharging the contaminants be-ing settled down.
Part of the purified liquid may be used as the ele-ctrolyte and returned by way of pipes 5 and 20 and a re-cycle line 21 having valves 22 to the lower section of the coagulation chamber 4 where the consumable electrod 6 are disposed. Filters 23 are further provided in the pipe 2 and 20 to prevent penetration of contaminant par-ticles to the purified liquid.
~3~5~7(~
'or reducing the operating costs ~esociated with re-placing the consumable electrodes 6 the lower part of the coagulation chamber 4 accommodating theee electrodes 6 is faahioned a a detachable section mounted on a frame 24 having rollers 25.
he apparatus for electrochemical purification of contaminated liquid operates in the following manner.
Prior to purification of a contaminated liquid the interiore of the coagulation chamber 4 and settling chamb-er 1 are filled with a pure electrolyte (technically pure water, or water containing small amounts of NaCl), where-after a direct current voltage i9 applied to the electro-des 6 to cause their dissolution and emission ox gas bub-bles.
During interaction of the ions of the metal of the electrodes 6, such aR Al3~ or Fe3+, transferred to the water solution of the electrolyte by hydroxyle ions 0~
there are formed metal hydroxides Al(0~)3 or Fe(OH)3 cap-able of a high sorbtion capacity relative to the subst-ances contained in the cont~m;nated liquid being purified.
After some time (normally after 0.5 to 2 min.) the supply of the contaminated liquid to the mixer 7 through the sprinkler lO is initiated, which liquid is mixed the-rein with an ascending flow of the electrolyte comprise ing particle of metal hydroxide and gaæ bubbles entering through a hole in the lower perforated damping psrtition 9. As a result of coagulating action of the particles of metal hydroxides, impurities carried by the flow of li-~Z~;~5710 quid through the holes in the upper perforated damping par-tition 9 to the conical portion of the coagulation chamb-er 4 ten to grow in size. Such growth is further facili-tated through flotation of thua formed aggregates by the gas bubbles emitted by the electrode. Because the section of the coagulation chamber 4 im~lediately above the mixer 7 is conical, the speed of travel of the -treated liquid there tends to slow down, since as the flow of liquid a-cende, the cros~-~3ectional area ox the coagulation chamber 4 expand. rl'his prevents collision of the aggregates and therefore their breaking as a result of less vigorous mix-ing action in the conical portlon of the chamber 4. There-fore, the coagulated contaminants tend to accumulate in the froth collector 13 above the layer of liquid in the coagulation chamber 4 to be thereafter evacuated by the air injector 16. the liquid being purified it paused thro-ugh the filter 17, where it is additionally cleared of the contaminants, to a zone between the conical section of the coagulation chamber 4 and the separating wall 14.
By virtue of the fact that this wall 14 is fashioned a a truncated cone with the small base thereof in the down position, the speed of travel of the purified liquid in-creaseG as it moves from top to bottom. Solid particles which failed to be filtered by the filter 17 are carried by the deacending flow to be stopped by the vertical par-titions 18 wherefrom they are later evacuated through the outlet pipe 19. These vertical partitiona 18 may be in-clined, depending on the type of contaminated liquid pro-1i~32'~70 cessed in the apparatus and the content in the purified liquid of particles of various degree of fineness.
Thereafter, the purified liquid it parted through the filter 23 and discharged through the pipe 2.
Part of the purified liquid may be used a electro-lyte supplied to the lower section of the coagulation cham-ber 4 through the pipe 5 and 20 and the recycle line 21 to where the consumsble electrode 6 are disposed. This re3ults in a saving of the technically pure water consum-able for the purpose.
The use of the proposed apparatus for electrochemical purification of contaminated liquids make it possible to attain a l.l to 1.8 increase in efficiency of liquid treat-ment through envigorating coagulation of contaminants pre-Kent in the liquid, reduce the rate of breaking up of the contaminant aggregates due to slowing down of the speed at which they are delivered to the separating zone, and assure a predetermined degree of liquid purification ox up to between 98.4 and 99.8 I.
PVRIFICATION OF CONTAMINATED LIQUIDS
his invention relate generally to the art of li-quid purification, and more particularly to an apparatus for electrochemical purification of contaminated liquids.
The device according to the invention can find ap-plication for purifying liquids contaminated by various impurities nonsoluble in water, such as organic matter, solid suspensions, and the like.
The apparatus of the invention may be utilized with the utmost advantage for purifying liquids polluted by petrolium products and polyrners, such as industrial sew-age containing oils and polymethyl methacrylates.
Among the presently known devices for purifying contaminated liquids an ever increasing use have found lately apparatuses for electrochemical purification of liquids due to their high process efficiency, particular-ly apparatuses capable of effecting electrocoagulation and electroflotation waste water treatment processes.
There are known apparatuses or carrying out elect-rochemical purification of contaminated liquids in in-termittent or in continuous modes of operation, the lat-ter appearing to be more promising.
One such apparatus for electrochemical purification of contaminated liquids comprises a settling chamber hav-ing outlet pipes for discharging the purified liquid and wastes wormed in the course of purification, this ~3~2S'~O
settling chamber partially embracing a coagulation chamb-er dieposed coaxially therein to underlie a froth collect-or, the bottom part of this chamber accommodating a pipe for feeding an electrolyte, and consumable electrodes above which there i9 disposed a mixer provided with an inlet pipe for supplying the contaminated liquid (cf., e.g., USSR Inventor's Certificate No. 644,738; IPC C
02F l/46, published 1979).
The coagulation chamber of this apparatus has an invariable cross-section in terms of height thereof.
In such a structural arrangement of the coagulation chamber wherein consolidation of the particles contained in the liquid being purified occur a certain constric-tion to the mOvement of aggregates of such particles tak-en place to result in partial breaking up of such parti-cles when they collide after being carried up by bubbles of gas emitted from the consumable electrodes.
This effects the efficiency of the apparatus, since for attaining the required degree of purification it it necessary to reduce the rate of feeding the contaminated liquid when the percentage of impurities contained there-in it increased, otherwise the split aggregates of impu-ritie~ vJill tend to be carried by the flow of purified liquid thereby affecting the quality of purification.
There it also known an apparatus for electrochemical purification of contaminated liquids (cf. USSR Inventor certificate No. 914,506; IPC C 02 l/46, published i982) comprising a settling chamber with outlet pipe for dip-~3~57(~
charging purified liquid and wastes communicable witha coagulation chamber arranged coaxially therein, the lover portion of this coagulation chamber accommodating an inlet pipe for feeding an electrolyte and a system of consumable electrodes and having a pipe for supplying a contaminated liquid to said chamber disposed abcve the consumable electrodes, and also a separating wall inter-posed between the settling chamber and the electrocoagu-lation chamber. Secured above the electrocoagulation cham-ber i8 a froth collector provided with an air injector for evacuating Roth waste from the apparatus.
The separating wall of this apparatua i9 cylindrical in shape and mounted in parallel with the walls of the electrocoagulation chamber. One more disadvantage of this construction is that the flow rate of the liquid being purified i6 maintained invariable in the zone confined by the separating wall and electrocoagulation chamber, which hampers an increase in the throughput capacity of the apparatus.
It is an object of this invention to provide an appa-ratus fox electrochemical purification of-contaminated liquids of such a construction as to prevent aggregates of particles formed during coagulation from being broken up .
In ac_ordance with the present nvention, there s thus provided an apparatus for electrochemical purification of contaminated liquids,comprising a settling chamber with ~;
~23;~S70 outlet pipes for discharging the purified liquid and wastes a coagulation chamber partially embraced by the settling chamber and arranged coaxially therewithi a froth collector provided wi-th an air injector mounted substantially above -the coagulation chamberi consumable electrodes arranged in the lower part of said coagulation chamberi an inlet pipe for feeding an electrolyte arranged in the bottom part of the coagulation chamber under said consumable electrodes; a mixer having an inlet pipe for supplying thereto a contaminated liquid and provided with perfo-rated damping partitions, the mixer being mounted inside the coagulatlon chamber above the consumable electrodes;
a separating wall interposed between the settling chamber and the coagulation chamber; part of the coagulation chamber disposed inside the settling chamber and the separating wall being in the form of truncated cones having upper larger bases and lower smaller bases with the larger bases facing the froth collector.
The aforedescribed arrangement provides more favour-able conditions for the impurities contained in the con-taminated liquid to coagulate by metal hydroxides produc-ed as a result of electrochemical dissolution of the ele-ctrodes in the pure electrolyte and carried to the mixer by the ascending flow. Constriction to the movement of the aggregates of impurities formed during coagulation and traveling upwards toward the liquid surface and their breaking up is prevented thanks to the disposition of the part of the coagulation chamber inside the settling chamb-.
~32S~7~
- 4a -er above the mixer and fashioning it as a truncated cone with the large base thereof facing the froth collector.
This advantageous effect is attained thanks to that the speed of the ascending flow of liquid tends to slow down , I, b ~3Z~i70 toward the liquid sur~aee due to the upwardly expanding cros~-sectional area of the coagulation chamber. Another attending advantage resides in the lack of excessive stir-ring of the particles of impurities being carried up which otherwise may split apart and affect the efficiency of the apparatus.
Preferably, the part of coagulation chamber disposed inside the settling chamber and fashioned a a truncated cone has a ratio between the area of it upper and lower bases within a range of 6.0 : 1Ø
Such an arrangement of the part of the eoagulation chamber in the form of a truncated cone with the above ra-tio between its upper and lower bases assures reduction in the speed of travel of the aseending flow of liquid to a value facilitating the formation of large aggregates of impurities, which tend to aecumulate at the suxface of the liquid under the froth collector to be evacuated the-refrom by~the air injector, makes the purification process 1.1 to i times more efficient. A further increase in this ratio leads to an increase in the amount of metal consumed for fabrication of the apparatus without adding tangibly effect to the efficiency thereof. Advisably, a filter is provided between the upper bates of the coagu-lation chamber and separating wall, vertical partition bein8 secured under the small base of the separating wall in the settling chamber, these vertical partitions over-lying outlet pipes for evacuating wastes tending to 3ettle down in the settling chamber:
~'~3~7(~
The provision of the filter enables to envigorate the process ox separation of the aggregates of impurities from the liquid, and consequently to increase the degree to which the contaminated liquid i8 purified and improve the efficiency of the apparatus.
The employment in the lower part of the settling chamber under the separating wall of vertical partitions makes it possible to slow down the speed of the flow of purified liquid pausing between the small baee ox the ye-parating wall and coagulation chamber, since the flow of liquid is passed through the spaces between said vertical partitions. This also promotes settling of the particles of impurities thanks to a sudden loss of the kinetic ener-gy of these impurities on the partitions, which again mak-es the apparatus more efficient and favours the purifica-tion process. As the wastes accumulate between the vertic-al partitions, they are periodically evacuated from the apparatus. These partitions may otherwise be inclined to the horizontal, depending on the type of the liquid being purified and on the presence of heterogeneous particles of impurities.
- Preferably, the perforated damping partitions secur-ed in the mixer are fashioned as cones with tops thereof facing the froth collector, a sprinkler being provided bet-ween the perforated damping paritions to assure a highly vigorous mixing of the contaminated liquid with the ascend-ing flow of the electrolyte.
The use of the perforated damping partitions in the ~3Z~70 mixer enables to envigorate mixing of the contaminated liquid with the electrolyte containing metal hydroxides and gas bubbles produced in the electrolyte in the course of electrochemical dissolution of the electrode. Such vigorous mixing facilitates the rate of coagulation of the particle of impurities through their interaction with the metal hydroxide. This i8 also promoted by the presence in the mixer of the sprinkler feeding the contaminated li-quid to the flow of the electrolyte. The sprinkler and the perforated damping partitions act to confine the area of mixing which is advantageous, since expansion of the mix-ing zone may result in breaking up of the coagulated ag-gregate~ of impurities. From the mixer the flow of treat-ed liquid escape through a hole in the upper damping par-tition~ which prevents a further stirring of the flows thereabove. Excessive stirring is also prevented thanks to that the section of the coagulation chamber overlying the mixer expand upwardly to slow down the speed of tra-vel of the liquid.
The conical upward pointing damping partitions pre-vent the accumulation in the mixer of gas and aggregates of impurities entrained by the ascending flow of liquid in the coagulation chamber. The provision of the zone of vigorous mixing of the contam1nated liquid with the as-cending flow of the electrolyte speeds up the rate of pu-rification and consequently results in increased through-put capacity of the apparatus.
The invention will now be dbscribed in greater ^de-~23257~
tail with reference to various specific embodiments there-of taken in conjunction with the accompanying drawings the sole Figure of which represents a general vieY~ of an apparatus for electrochemical purification of contaminat-ed liquids.
An apparatus for electrochemical purification of contaminated liquid according to the invention compri~e~
a settling chamber 1 having outlet pipes 2 and 3 for diæ-charging the purified liquid and wastes, respectively,this settling chamber 1 partially embracing a coagulation cham-ber 4 mounted coaxiall~ therein.
q`he lower section of the coagulation chamber 4 pro-jecting away from the settling chamber 1 accol~modate~ an inlet pipe 5 for feeding an electrolyte and con6umable ele-ctrodes 6. A mixer 7 with a pipe 8 for supplying a conta-minated liquid are arranged above the consumable elect-rodes 6. the mixer 7 is provided with perforated damping partitionæ 9 of conical configuration with tops of the cones pointing upwards. A sprinkler 10 is interposed bet-ween the damping partitions 9 to provide for vigorous mix-ing of the contaminated liquid supplied through the inlet pipe 8 with an ascending flow of electrolyte.
Part of the coagulation chamber 4 arranged coaxially inside the settling chamber 1 ha the form of a truncated cone 11 facing by its large base toward a froth collector 13, the ratio of this large baæe 12 to the small bate of the truncated cone making up this part of the coagulation chamber 4 being preferably 6.9~1Ø
~2325~0 The arrangement of the part of the chamber 4 in the form of a truncated cone with the above ratio between the surface areas of it large and small bases ensures a gra-dual reduction in the speed of the flow of liquid inside the chamber 4 to a value promoting the formation of large-size particles of impurities and preventing these parti-cles from breaking up due to reduced mixing of the system.
Di~po~ed between the settling ohamber 1 and the co-nical part of the coagulation chamber 4 it a separating wall 14 also having the form of a truncated cone with a large base 15 thereof facing the froth collector 13. The froth collector 13 i6 provided in its top part with an injector 16 serving to evacuate wastes formed of as Roth above the level of liquid in the coagulation chamber 4.
In order to envigorate the process of separating wastes from the liquid, a filter 17 it secured between the upp-er bases 12 and 15 of the coagulation chamber 4 and the eeparating wall 14, respectiYely, while under the ~epa-rating wall 14 there are arranged vertical partitions 18 and outlet pipes 19 for discharging the contaminants be-ing settled down.
Part of the purified liquid may be used as the ele-ctrolyte and returned by way of pipes 5 and 20 and a re-cycle line 21 having valves 22 to the lower section of the coagulation chamber 4 where the consumable electrod 6 are disposed. Filters 23 are further provided in the pipe 2 and 20 to prevent penetration of contaminant par-ticles to the purified liquid.
~3~5~7(~
'or reducing the operating costs ~esociated with re-placing the consumable electrodes 6 the lower part of the coagulation chamber 4 accommodating theee electrodes 6 is faahioned a a detachable section mounted on a frame 24 having rollers 25.
he apparatus for electrochemical purification of contaminated liquid operates in the following manner.
Prior to purification of a contaminated liquid the interiore of the coagulation chamber 4 and settling chamb-er 1 are filled with a pure electrolyte (technically pure water, or water containing small amounts of NaCl), where-after a direct current voltage i9 applied to the electro-des 6 to cause their dissolution and emission ox gas bub-bles.
During interaction of the ions of the metal of the electrodes 6, such aR Al3~ or Fe3+, transferred to the water solution of the electrolyte by hydroxyle ions 0~
there are formed metal hydroxides Al(0~)3 or Fe(OH)3 cap-able of a high sorbtion capacity relative to the subst-ances contained in the cont~m;nated liquid being purified.
After some time (normally after 0.5 to 2 min.) the supply of the contaminated liquid to the mixer 7 through the sprinkler lO is initiated, which liquid is mixed the-rein with an ascending flow of the electrolyte comprise ing particle of metal hydroxide and gaæ bubbles entering through a hole in the lower perforated damping psrtition 9. As a result of coagulating action of the particles of metal hydroxides, impurities carried by the flow of li-~Z~;~5710 quid through the holes in the upper perforated damping par-tition 9 to the conical portion of the coagulation chamb-er 4 ten to grow in size. Such growth is further facili-tated through flotation of thua formed aggregates by the gas bubbles emitted by the electrode. Because the section of the coagulation chamber 4 im~lediately above the mixer 7 is conical, the speed of travel of the -treated liquid there tends to slow down, since as the flow of liquid a-cende, the cros~-~3ectional area ox the coagulation chamber 4 expand. rl'his prevents collision of the aggregates and therefore their breaking as a result of less vigorous mix-ing action in the conical portlon of the chamber 4. There-fore, the coagulated contaminants tend to accumulate in the froth collector 13 above the layer of liquid in the coagulation chamber 4 to be thereafter evacuated by the air injector 16. the liquid being purified it paused thro-ugh the filter 17, where it is additionally cleared of the contaminants, to a zone between the conical section of the coagulation chamber 4 and the separating wall 14.
By virtue of the fact that this wall 14 is fashioned a a truncated cone with the small base thereof in the down position, the speed of travel of the purified liquid in-creaseG as it moves from top to bottom. Solid particles which failed to be filtered by the filter 17 are carried by the deacending flow to be stopped by the vertical par-titions 18 wherefrom they are later evacuated through the outlet pipe 19. These vertical partitiona 18 may be in-clined, depending on the type of contaminated liquid pro-1i~32'~70 cessed in the apparatus and the content in the purified liquid of particles of various degree of fineness.
Thereafter, the purified liquid it parted through the filter 23 and discharged through the pipe 2.
Part of the purified liquid may be used a electro-lyte supplied to the lower section of the coagulation cham-ber 4 through the pipe 5 and 20 and the recycle line 21 to where the consumsble electrode 6 are disposed. This re3ults in a saving of the technically pure water consum-able for the purpose.
The use of the proposed apparatus for electrochemical purification of contaminated liquids make it possible to attain a l.l to 1.8 increase in efficiency of liquid treat-ment through envigorating coagulation of contaminants pre-Kent in the liquid, reduce the rate of breaking up of the contaminant aggregates due to slowing down of the speed at which they are delivered to the separating zone, and assure a predetermined degree of liquid purification ox up to between 98.4 and 99.8 I.
Claims (7)
1. An apparatus for electrochemical purification of contaminated liquids comprising a settling chamber with outlet pipes for discharging the purified liquid and wa-stes; a coagulation chamber partially embraced by said settling chamber and arranged coaxially therewith; a froth collector provided with an air injector mounted sub-stantially above said coagulation chamber; consumable ele-ctrodes arranged in the lower part of said coagulation chamber; an inlet pipe for feeding an electrolyte arrang-ed in the bottom part of said coagulation chamber under said consumable electrodes; a mixer having an inlet pipe for supplying thereto a contaminated liquid and provided with perforated damping partitions, the mixer being mount-ed inside said coagulation chamber above said consumable electrodes; 8 separating wall interposed between said settling chamber and said coagulation chamber; part of said coagulation chamber disposed inside said settling chamber and said separating wall being in the form of truncated cones having upper larger bases and lower smaller bases with the larger bases facing said froth collector.
2. An apparatus as defined in claim 1, wherein the ratio between the areas of the upper and lower bases of said conical portion of said coagulation chamber is with-in a range of 6 : 1.
3. An apparatus as defined in claim 1, wherein a filter is provided between said upper bases of said co-agulation chamber and separating wall.
4. An apparatus as defined in claim 1, wherein ver-tical partitions are secured under said smaller base of said separating wall in said settling chamber, these ver-tical partitions overlying outlet pipes for evacuating wastes being settled down.
5. An apparatus as defined in claim 1, wherein said damping partitions provided in said mixer are fashioned as cones with tops thereof facing said froth collector.
6. An apparatus as defined in claim 1, wherein a sprinkler is disposed inside said mixer between said per-forated damping partitions to assure a highly vigorous mixing of the contaminated liquid with an ascending flow of the electrolyte.
7. An apparatus as defined in claim 5, wherein a sprinkler is disposed inside said mixer between said per-forated damping partitions to assure a highly vigorous mixing of the contaminated liquid with an ascending flow of the electrolyte.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000455856A CA1232570A (en) | 1984-06-05 | 1984-06-05 | Apparatus for electrochemical purification of contaminated liquids |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000455856A CA1232570A (en) | 1984-06-05 | 1984-06-05 | Apparatus for electrochemical purification of contaminated liquids |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1232570A true CA1232570A (en) | 1988-02-09 |
Family
ID=4128031
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000455856A Expired CA1232570A (en) | 1984-06-05 | 1984-06-05 | Apparatus for electrochemical purification of contaminated liquids |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1232570A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10669170B2 (en) | 2015-10-08 | 2020-06-02 | Axolot Solutions Holding Ab | Electroflotation apparatus having an outlet pipe with a low turbulence orifice |
-
1984
- 1984-06-05 CA CA000455856A patent/CA1232570A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10669170B2 (en) | 2015-10-08 | 2020-06-02 | Axolot Solutions Holding Ab | Electroflotation apparatus having an outlet pipe with a low turbulence orifice |
| EP3359493B1 (en) * | 2015-10-08 | 2020-12-30 | Axolot Solutions Holding AB | Electroflotation apparatus having an outlet pipe with a low turbulence orifice |
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