CA2003128C - Process and apparatus for the biological purification of sewage - Google Patents
Process and apparatus for the biological purification of sewage Download PDFInfo
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- CA2003128C CA2003128C CA 2003128 CA2003128A CA2003128C CA 2003128 C CA2003128 C CA 2003128C CA 2003128 CA2003128 CA 2003128 CA 2003128 A CA2003128 A CA 2003128A CA 2003128 C CA2003128 C CA 2003128C
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- settling tank
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- 239000010865 sewage Substances 0.000 title claims abstract description 66
- 238000000034 method Methods 0.000 title claims abstract description 32
- 238000000746 purification Methods 0.000 title claims abstract description 7
- 239000000126 substance Substances 0.000 claims abstract description 33
- 239000010802 sludge Substances 0.000 claims abstract description 18
- 239000000203 mixture Substances 0.000 claims abstract description 17
- 239000003344 environmental pollutant Substances 0.000 claims abstract description 7
- 231100000719 pollutant Toxicity 0.000 claims abstract description 7
- 238000000354 decomposition reaction Methods 0.000 claims description 6
- 238000005192 partition Methods 0.000 claims description 6
- 239000002351 wastewater Substances 0.000 claims description 4
- 238000000926 separation method Methods 0.000 claims description 3
- 230000000630 rising effect Effects 0.000 claims description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 10
- 239000001301 oxygen Substances 0.000 description 10
- 229910052760 oxygen Inorganic materials 0.000 description 10
- 239000007789 gas Substances 0.000 description 9
- 244000005700 microbiome Species 0.000 description 8
- 230000015556 catabolic process Effects 0.000 description 5
- 238000006731 degradation reaction Methods 0.000 description 5
- 238000010008 shearing Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 241000894006 Bacteria Species 0.000 description 2
- 230000000875 corresponding effect Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 235000015097 nutrients Nutrition 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 230000005514 two-phase flow Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/02—Aerobic processes
- C02F3/12—Activated sludge processes
- C02F3/1278—Provisions for mixing or aeration of the mixed liquor
- C02F3/1294—"Venturi" aeration means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/20—Mixing gases with liquids
- B01F23/23—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids
- B01F23/232—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using flow-mixing means for introducing the gases, e.g. baffles
- B01F23/2323—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using flow-mixing means for introducing the gases, e.g. baffles by circulating the flow in guiding constructions or conduits
- B01F23/23231—Mixing gases with liquids by introducing gases into liquid media, e.g. for producing aerated liquids using flow-mixing means for introducing the gases, e.g. baffles by circulating the flow in guiding constructions or conduits being at least partially immersed in the liquid, e.g. in a closed circuit
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/40—Mixing liquids with liquids; Emulsifying
- B01F23/45—Mixing liquids with liquids; Emulsifying using flow mixing
- B01F23/454—Mixing liquids with liquids; Emulsifying using flow mixing by injecting a mixture of liquid and gas
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
- B01F25/20—Jet mixers, i.e. mixers using high-speed fluid streams
- B01F25/21—Jet mixers, i.e. mixers using high-speed fluid streams with submerged injectors, e.g. nozzles, for injecting high-pressure jets into a large volume or into mixing chambers
- B01F25/211—Jet mixers, i.e. mixers using high-speed fluid streams with submerged injectors, e.g. nozzles, for injecting high-pressure jets into a large volume or into mixing chambers the injectors being surrounded by guiding tubes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
- B01F25/20—Jet mixers, i.e. mixers using high-speed fluid streams
- B01F25/23—Mixing by intersecting jets
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Microbiology (AREA)
- Hydrology & Water Resources (AREA)
- Biodiversity & Conservation Biology (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Organic Chemistry (AREA)
- Biological Treatment Of Waste Water (AREA)
- Aeration Devices For Treatment Of Activated Polluted Sludge (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Physical Water Treatments (AREA)
- Activated Sludge Processes (AREA)
Abstract
A process for the biological purification of sewage is specified, with which sewage (AW), containing dissolved pollutants, and air (LT) are fed together to a reactor (1) via at least two mutually separate nozzles (3, 4). To achieve a high substance exchange in the reactor (1), the streams of the two-substance mixture emanating from the nozzles (3, 4) are conducted such that they make impact with each other in the said reactor in an impact zone (PZ). The sewage (AW) is passed from the reactor (1) into Pa settling tank (8), in which bio sludge settles.
Description
Description The invention relates to a process for the biological purification of sewage, with which sewage, containing dissolved pollutants, and air are introduced together under pressure, via at least one nozzle into a reactor designed as a tank and are passed on in the reactor as a two-substance mixture, as well as to an apparatus for carrying out the process.
In the biological purification of sewage, pollutants dissolved in the same are degraded by bacteria or micro organisms. In order to increase their effectiveness or to accelerate their multiplication, oxygen is fed to the sewage . This can take place by supplying air or else pure oxygen. Often, nutrients are also fed to the sewage. In the case of known sewage treatment plants, this takes place in so-called activated sludge tanks. The sludge biologically produced thereby is separated from the purified waste water in a downstream sedimentation tank.
The tanks used for this process have a large space requirement. In spite of this, the biological degradation rate is not satisfactory and the open design often leads to a very disturbing odour nuisance for the surroundings .
Therefore, processes have been developed in which, instead of the activated sludge tank, high-performance reactors with significantly reduced space requirement and increased biological degradation rate are used. Such a process, described at the beginning, emerges from the German journal "Chew. Ind. XXXVII/January 1985", pages 43 to 46. In this process, a compact reactor is used which consists of a cylindrical tank, in which a cylindrical insert tube, open at both ends, is arranged. A mixture consisting of sewage and air is introduced into the insert tube via a two-substance nozzle. The air fed via the two-substance nozzle is dispersed into tiny bubbles on account of great shearing forces in the region of the two-substance nozzle, so that a large exchange surface is produced and the charge of oxygen is favourably influenced. With this known process, the biological degradation rate can be increased considerably in com-parison with conventional processes with activated sludge 2UU~~28 tanks. However, since the high substance exchange takes place essentially in the region of the two-substance nozzle and the turbulence in the insert tube is damped relatively quickly by the sewage, this process also is unsatisfactory in many cases.
The invention is based on the object of specifying a process for the purification of sewage, with which the substance exchange upon introduction of oxygen into the sewage is significantly increased.
According to the invention, this object is achieved by a process of the type described at the beginning by - the sewage and the air being fed to the reactor via at least two mutually separate nozzles, - the streams of, the two-substance mixture emanating from the nozzles being conducted in the reactor such that they make impact with each other in the said reactor in an impact zone and - by the sewage being passed after de composition from the reactor into a settling tank.
Due to the shearing field of the sewage in the direct region behind the openings of the nozzles, on leaving the nozzles, the air is divided into very small bubbles. At the same time, the sewage jets emanating from the nozzles suck in sewage or an air/sewage mixture from the inside of the reactor. As~'a result, homogeneous two-substance streams form downstream of the nozzles. The two-substance streams are deflected, for example by elbows, such that they collide within the reactor in the impact zone, in which the air bubbles are divided further. The kinetic energy of the flowing air/sewage mixture is thereby dissipated. As a result, a high turbulence and a large substance exchange surface in the impact zone and in the other parts of the reactor above and below the impact zone are produced. With the same ?5 energy charge as in tha case of the known process, the substance exchange thus achieved is significantly higher.
Thus, with this process, in a simple way significantly more oxygen is introduced into the sewage than was previously possible. The process therefore makes possible 2a'~~ 128 a considerably increased biological degradation rate.
Advantageous developments of the invention, which also concern in particular an apparatus for carrying out the process, emerge from the subclaims.
Process and apparatus according to the invention are explained in exemplary embodiments with reference to the drawings in which:
Fig. 1 shows in diagrammatic representation an apparatus for carrying out the process according to the invention, Figs. 2 and 3 show two apparatuses added to in comparison with Fig. 1 and with different arrangement of the nozzles, Figs. 4 and 5 show two apparatuses modified in comparison with Figs. 2 and 3, Figs. 6 and 7 show two further developments of the apparatus.
In a reactor 1, which is preferably designed as an elongated cylinder, air LT and sewage AW, containing dissolved pollutants, are to be mixed with each other. In this process, as large a quantity as possible of oxygen contained in the air LT is to be introduced into the sewage AW. The reactor 1 opens out with its upper end, in working position, into a compartment 2. Two nozzles 3 and 4, to which the sewage AW on the one hand and the air LT
on the other hand are fed, are arranged in the compart-ment 2. The nozzles 3 and 4 are in this case arranged such that the jets emanating from them pass into conduit tubes 5 and 6, which for their part open out into the reactor 1 at two diametrically opposite points.
The conduit tubes 5 and 6 may - as is evident from the drawings - run substantially parallel to the reactor 1 and, after passing around an elbow, of preferably 90°, are connected to the reactor 1. The two-substance mixtures of sewage AW and air LT, conducted separately in the conduit tubes 5 and 6, meet each other in the reactor 1 in an impact zone PZ outlined by broken lines. The sewage can rise upwards according to the arrow 7, from where it passes after decomposition via the compartment 2 into a settling tank 8. The excess air (remaining oxygen and atmospheric nitrogen) can escape as exhaust gas according to the broken-line arrow 9 from the compartment 2 via a filter 10. Exhaust gas escaping from the settling tank 8 can also be passed via the filter 10.
In the compartment 2 there is a weir,ll fitted, by which the decomposition necessary for the separate outflow or discharge of sewage and exhaust gas is achieved. The height of the weir 11 is variable.
Two nozzles 3 and 4 are in each case represented in the drawings. However, more than two nozzles, mutually separate in each case, may also be used. They are prefer-ably made from two concentric tubes as two-substance nozzles . As far as geometry and dimensions are concerned, the nozzles 3 and 4 are preferably identically designed, so that the reactor 1 is fed two or more uniform streams of the two-substance mixture.
The arrangement of the conduit tubes 5 and 6 with a substantially parallel run to the reactor 1 is not obligatory. They could also run obliquely to the reactor 1': The conduit tubes 5 and 6 also do not have to open out into the reactor 1 such that the emanating streams meet each other frontally in the impact zone PZ. Rather, the streams could also make impact with each other at an angle other than 180°. In a preferred embodiment, however, the streams make impact with each other frontally, that is to say at an angle of 180°.
If more than two nozzles 3 and 4 are used, the mouths of the corresponding conduit tubes 5 and 6 are expediently arranged evenly offset on the circumference of the reactor 1, thus, in the case of three nozzles, there is for example an angle of 120° in each case between the mouths. This also applies if the nozzles 3 and 4 open out directly into the reactor 1 without conduit tubes 5 and 6.
The process and apparatus according to Fig. 1 operate for example as follows:
The reactor 1 is fed sewage AW and air LT separately via the nozzles 3 and 4. For this purpose, the sewage AW, ~~~~j2a laden with dissolved pollutants and microorganisms, is delivered by means of a pump 12. On account of the shearing field of the sewage AW at the outlet openings of the nozzles 3 and 4 the air LT is dispersed. The gas bubbles produced are entrained by the sewage AW and the two-substance mixture thus produced makes impact with each other in two streams in the impact zone PZ. As a result, the gas bubbles are further dispersed, so that an increased substance exchange takes place. Starting from the impact zone PZ, two two-substance flows lead in opposite directions within the reactor 1, according to the arrows 7 and 13. It is achieved as a result that a large part of the gas bubbles in the impact zone PZ
remains in suspension and is constantly dispersed further. This leads to a further increase in the sub-stance exchange. For this reason, in a preferred embodi-ment, the impact zone PZ is created in the reactor 1 as centrally as possible, that is to say approximately in the middle.
~ For further improvement of the substance exchange, the two-substance mixture within the reactor 1 may also be conducted in an internal circuit, which is intended to be indicated by the arrows 14. For this purpose, after decomposition, the sewage may also be removed from the reactor 1 in the direction of the arrow 13 and fed by means of a pump 15 back to the nozzles 3 and 4, to be precise together with the sewage AW delivered by the pump 12.
The sewage emanating from the reactor 1 upwards in the direction of the arrow 7 passes into the compartment 2. From there, after decomposition, it is passed through the weir 11 in the direction of the arrow 16 into the settling tank 6, in which the bio sludge containing microorganisms settles and separates from the purified waste water. The waste water can be released into the recipient in the direction of the arrow 17. The bio-sludge can be removed as excess sludge in the direction of the arrow 18 and fed to further processing.
In the case of the embodiments of the apparatus 2fl0~ ~ 28 according to Figs. 1 and 2, the nozzles 3 and 4 are arranged in the upper region of the reactor 1. According to Fig. 3, they may also be fitted in the lower region of the reactor 1. This does not change the operating principle of the apparatus.
The microorganisms required for the purification of the sewage are contained in the bio-sludge settling in the settling tank 8. It is therefore particularly expedient if a part of the bio-sludge is conducted back into the reactor 1 together with the sewage AW . A cor-responding complete apparatus is evident from Figs. 2 and 3:
The sewage AW to be gurified, delivered by the pump 12, and bio-sludge delivered from the settling tank 8 by means of a pump 19 are mixed with the sewage to be returned into the reactor 1 (pump 15) and conducted into the reactor 1 with oxygen-containing air LT via the nozzles 3 and 4. The sewage streams emanating from the nozzles 3 and 4 with the bio-sludge and the evenly distributed gas bubbles are - as already described for Fig. 1 - conducted through the conduit tubes 5 and 6 and deflected by the elbows of the latter. They finally collide within the reactor 1. In the impact zone PZ, again a high substance exchange takes place, on the one hand between the sewage AW and the air LT and on the other hand between the sewage AW and the microorganisms.
The apparatuses according to Figs . 4 and 5 differ from those of Figs. 2 and 3 in that the reactor 1 is integrated with the settling tank 8, which is set on the reactor 1 on the upper end, in working position of the said reactor instead of the compartment 2. The separation of the sewage in the reactor 1 from the sewage in the settling tank 8 is performed by a rotating, preferably cylindrical, partition wall 20. In Fig. 4, the gassing of the sewage from above is represented and in Fig. 5 from below. Since, in gassing from below, the nozzles 3 and 4 can suck in the sludge to be returned from the settling tank 8 into the reactor 1, the use of the pump 19 for the return of the bio-sludge can be dispensed with in the ~ou~~2 _,_ case of this apparatus.
The reactor 1 is distinguished by a very high substance exchange rate. This means that only a small reactor volume and a small average residence time are required in order to achieve a certain oxygen concentra-tion in the sewage. The space requirement for the degrad-ation of the pollutants dissolved in the sewage to be achieved by the microorganisms is higher than that for the intensive gassing of the sewage AW in the reactor 1.
The separation of the reactor space into two zones can therefore lead to a reduction in the energy requirement.
Fig. 6 shows such an apparatus for the case where the gassing of the reactor 1 is performed from below.
The first zone corresponds to the reactor 1, into which a high volume-related output is introduced. In this zone, the oxygen concentration in the sewage AW is greatly increased (>~ 2 mg/1) and very small bacteria agglomerates with a large volume-related exchange surface are generated by the bio-sludge in the sewage. The second zone contains the volume of the sewage within the partition wall 20 and above the reactor 1. In this space, a cylindrical circulation tube 21 may preferably be fitted concentrically to the partition wall 20. Due to the pulsed stream of the two-phase flow emanating from the reactor 1 and the upward force of the rising gas bubbles, a sewage circulation takes place in this zone.
An oxygen exchange between the gas bubbles and the sewage likewise takes place in the second zone. However, compared with the first zone, this substance exchange occurs with reduced intensity. In the annular gap between the circulation tube 21 and the partition wall 20, the sewage flows downwards. At the lower end of the annular gap, a part of the downwardly directed sewage stream is deflected back into the' circulation tube 21. The remaining part of the sewage stream passes into the settling tank 8. The bio-sludge is sucked in by the settling tank 8 by means of the nozzles 3 and 4, (or, if appropriate, by means of a pump) and partially returned into the reactor 1.
2~~~128 _8_ The second zone may also be provided with a fixed bed 22 in the form of a fill or an ordered pack. The fixed bed 22 has the effect of immobilising the micro-organisms contained in the sewage and increasing their concentration in this zone. In order that the sewage circulation in the second zone is not excessively damped by the fixed bed 22, the said bed is preferably only arranged in the annular gap between partition wall 20 and circulation tie 21, as can be seen from Fig. 7.
By increasing the concentration of microorganisms in the second zone by means of the fixed bed 22, the requirement for bio-sludge to be returned from the settling tank 8 can be dispensed with completely.
In the case of the apparatuses according to Figs. 6 and 7, the nozzles 3 and 4 can be fitted to the reactor 1 at the bottom. However, they may also be arranged at the top, as emerges in principle from Figs. 1, 2 and 4.
In the biological purification of sewage, pollutants dissolved in the same are degraded by bacteria or micro organisms. In order to increase their effectiveness or to accelerate their multiplication, oxygen is fed to the sewage . This can take place by supplying air or else pure oxygen. Often, nutrients are also fed to the sewage. In the case of known sewage treatment plants, this takes place in so-called activated sludge tanks. The sludge biologically produced thereby is separated from the purified waste water in a downstream sedimentation tank.
The tanks used for this process have a large space requirement. In spite of this, the biological degradation rate is not satisfactory and the open design often leads to a very disturbing odour nuisance for the surroundings .
Therefore, processes have been developed in which, instead of the activated sludge tank, high-performance reactors with significantly reduced space requirement and increased biological degradation rate are used. Such a process, described at the beginning, emerges from the German journal "Chew. Ind. XXXVII/January 1985", pages 43 to 46. In this process, a compact reactor is used which consists of a cylindrical tank, in which a cylindrical insert tube, open at both ends, is arranged. A mixture consisting of sewage and air is introduced into the insert tube via a two-substance nozzle. The air fed via the two-substance nozzle is dispersed into tiny bubbles on account of great shearing forces in the region of the two-substance nozzle, so that a large exchange surface is produced and the charge of oxygen is favourably influenced. With this known process, the biological degradation rate can be increased considerably in com-parison with conventional processes with activated sludge 2UU~~28 tanks. However, since the high substance exchange takes place essentially in the region of the two-substance nozzle and the turbulence in the insert tube is damped relatively quickly by the sewage, this process also is unsatisfactory in many cases.
The invention is based on the object of specifying a process for the purification of sewage, with which the substance exchange upon introduction of oxygen into the sewage is significantly increased.
According to the invention, this object is achieved by a process of the type described at the beginning by - the sewage and the air being fed to the reactor via at least two mutually separate nozzles, - the streams of, the two-substance mixture emanating from the nozzles being conducted in the reactor such that they make impact with each other in the said reactor in an impact zone and - by the sewage being passed after de composition from the reactor into a settling tank.
Due to the shearing field of the sewage in the direct region behind the openings of the nozzles, on leaving the nozzles, the air is divided into very small bubbles. At the same time, the sewage jets emanating from the nozzles suck in sewage or an air/sewage mixture from the inside of the reactor. As~'a result, homogeneous two-substance streams form downstream of the nozzles. The two-substance streams are deflected, for example by elbows, such that they collide within the reactor in the impact zone, in which the air bubbles are divided further. The kinetic energy of the flowing air/sewage mixture is thereby dissipated. As a result, a high turbulence and a large substance exchange surface in the impact zone and in the other parts of the reactor above and below the impact zone are produced. With the same ?5 energy charge as in tha case of the known process, the substance exchange thus achieved is significantly higher.
Thus, with this process, in a simple way significantly more oxygen is introduced into the sewage than was previously possible. The process therefore makes possible 2a'~~ 128 a considerably increased biological degradation rate.
Advantageous developments of the invention, which also concern in particular an apparatus for carrying out the process, emerge from the subclaims.
Process and apparatus according to the invention are explained in exemplary embodiments with reference to the drawings in which:
Fig. 1 shows in diagrammatic representation an apparatus for carrying out the process according to the invention, Figs. 2 and 3 show two apparatuses added to in comparison with Fig. 1 and with different arrangement of the nozzles, Figs. 4 and 5 show two apparatuses modified in comparison with Figs. 2 and 3, Figs. 6 and 7 show two further developments of the apparatus.
In a reactor 1, which is preferably designed as an elongated cylinder, air LT and sewage AW, containing dissolved pollutants, are to be mixed with each other. In this process, as large a quantity as possible of oxygen contained in the air LT is to be introduced into the sewage AW. The reactor 1 opens out with its upper end, in working position, into a compartment 2. Two nozzles 3 and 4, to which the sewage AW on the one hand and the air LT
on the other hand are fed, are arranged in the compart-ment 2. The nozzles 3 and 4 are in this case arranged such that the jets emanating from them pass into conduit tubes 5 and 6, which for their part open out into the reactor 1 at two diametrically opposite points.
The conduit tubes 5 and 6 may - as is evident from the drawings - run substantially parallel to the reactor 1 and, after passing around an elbow, of preferably 90°, are connected to the reactor 1. The two-substance mixtures of sewage AW and air LT, conducted separately in the conduit tubes 5 and 6, meet each other in the reactor 1 in an impact zone PZ outlined by broken lines. The sewage can rise upwards according to the arrow 7, from where it passes after decomposition via the compartment 2 into a settling tank 8. The excess air (remaining oxygen and atmospheric nitrogen) can escape as exhaust gas according to the broken-line arrow 9 from the compartment 2 via a filter 10. Exhaust gas escaping from the settling tank 8 can also be passed via the filter 10.
In the compartment 2 there is a weir,ll fitted, by which the decomposition necessary for the separate outflow or discharge of sewage and exhaust gas is achieved. The height of the weir 11 is variable.
Two nozzles 3 and 4 are in each case represented in the drawings. However, more than two nozzles, mutually separate in each case, may also be used. They are prefer-ably made from two concentric tubes as two-substance nozzles . As far as geometry and dimensions are concerned, the nozzles 3 and 4 are preferably identically designed, so that the reactor 1 is fed two or more uniform streams of the two-substance mixture.
The arrangement of the conduit tubes 5 and 6 with a substantially parallel run to the reactor 1 is not obligatory. They could also run obliquely to the reactor 1': The conduit tubes 5 and 6 also do not have to open out into the reactor 1 such that the emanating streams meet each other frontally in the impact zone PZ. Rather, the streams could also make impact with each other at an angle other than 180°. In a preferred embodiment, however, the streams make impact with each other frontally, that is to say at an angle of 180°.
If more than two nozzles 3 and 4 are used, the mouths of the corresponding conduit tubes 5 and 6 are expediently arranged evenly offset on the circumference of the reactor 1, thus, in the case of three nozzles, there is for example an angle of 120° in each case between the mouths. This also applies if the nozzles 3 and 4 open out directly into the reactor 1 without conduit tubes 5 and 6.
The process and apparatus according to Fig. 1 operate for example as follows:
The reactor 1 is fed sewage AW and air LT separately via the nozzles 3 and 4. For this purpose, the sewage AW, ~~~~j2a laden with dissolved pollutants and microorganisms, is delivered by means of a pump 12. On account of the shearing field of the sewage AW at the outlet openings of the nozzles 3 and 4 the air LT is dispersed. The gas bubbles produced are entrained by the sewage AW and the two-substance mixture thus produced makes impact with each other in two streams in the impact zone PZ. As a result, the gas bubbles are further dispersed, so that an increased substance exchange takes place. Starting from the impact zone PZ, two two-substance flows lead in opposite directions within the reactor 1, according to the arrows 7 and 13. It is achieved as a result that a large part of the gas bubbles in the impact zone PZ
remains in suspension and is constantly dispersed further. This leads to a further increase in the sub-stance exchange. For this reason, in a preferred embodi-ment, the impact zone PZ is created in the reactor 1 as centrally as possible, that is to say approximately in the middle.
~ For further improvement of the substance exchange, the two-substance mixture within the reactor 1 may also be conducted in an internal circuit, which is intended to be indicated by the arrows 14. For this purpose, after decomposition, the sewage may also be removed from the reactor 1 in the direction of the arrow 13 and fed by means of a pump 15 back to the nozzles 3 and 4, to be precise together with the sewage AW delivered by the pump 12.
The sewage emanating from the reactor 1 upwards in the direction of the arrow 7 passes into the compartment 2. From there, after decomposition, it is passed through the weir 11 in the direction of the arrow 16 into the settling tank 6, in which the bio sludge containing microorganisms settles and separates from the purified waste water. The waste water can be released into the recipient in the direction of the arrow 17. The bio-sludge can be removed as excess sludge in the direction of the arrow 18 and fed to further processing.
In the case of the embodiments of the apparatus 2fl0~ ~ 28 according to Figs. 1 and 2, the nozzles 3 and 4 are arranged in the upper region of the reactor 1. According to Fig. 3, they may also be fitted in the lower region of the reactor 1. This does not change the operating principle of the apparatus.
The microorganisms required for the purification of the sewage are contained in the bio-sludge settling in the settling tank 8. It is therefore particularly expedient if a part of the bio-sludge is conducted back into the reactor 1 together with the sewage AW . A cor-responding complete apparatus is evident from Figs. 2 and 3:
The sewage AW to be gurified, delivered by the pump 12, and bio-sludge delivered from the settling tank 8 by means of a pump 19 are mixed with the sewage to be returned into the reactor 1 (pump 15) and conducted into the reactor 1 with oxygen-containing air LT via the nozzles 3 and 4. The sewage streams emanating from the nozzles 3 and 4 with the bio-sludge and the evenly distributed gas bubbles are - as already described for Fig. 1 - conducted through the conduit tubes 5 and 6 and deflected by the elbows of the latter. They finally collide within the reactor 1. In the impact zone PZ, again a high substance exchange takes place, on the one hand between the sewage AW and the air LT and on the other hand between the sewage AW and the microorganisms.
The apparatuses according to Figs . 4 and 5 differ from those of Figs. 2 and 3 in that the reactor 1 is integrated with the settling tank 8, which is set on the reactor 1 on the upper end, in working position of the said reactor instead of the compartment 2. The separation of the sewage in the reactor 1 from the sewage in the settling tank 8 is performed by a rotating, preferably cylindrical, partition wall 20. In Fig. 4, the gassing of the sewage from above is represented and in Fig. 5 from below. Since, in gassing from below, the nozzles 3 and 4 can suck in the sludge to be returned from the settling tank 8 into the reactor 1, the use of the pump 19 for the return of the bio-sludge can be dispensed with in the ~ou~~2 _,_ case of this apparatus.
The reactor 1 is distinguished by a very high substance exchange rate. This means that only a small reactor volume and a small average residence time are required in order to achieve a certain oxygen concentra-tion in the sewage. The space requirement for the degrad-ation of the pollutants dissolved in the sewage to be achieved by the microorganisms is higher than that for the intensive gassing of the sewage AW in the reactor 1.
The separation of the reactor space into two zones can therefore lead to a reduction in the energy requirement.
Fig. 6 shows such an apparatus for the case where the gassing of the reactor 1 is performed from below.
The first zone corresponds to the reactor 1, into which a high volume-related output is introduced. In this zone, the oxygen concentration in the sewage AW is greatly increased (>~ 2 mg/1) and very small bacteria agglomerates with a large volume-related exchange surface are generated by the bio-sludge in the sewage. The second zone contains the volume of the sewage within the partition wall 20 and above the reactor 1. In this space, a cylindrical circulation tube 21 may preferably be fitted concentrically to the partition wall 20. Due to the pulsed stream of the two-phase flow emanating from the reactor 1 and the upward force of the rising gas bubbles, a sewage circulation takes place in this zone.
An oxygen exchange between the gas bubbles and the sewage likewise takes place in the second zone. However, compared with the first zone, this substance exchange occurs with reduced intensity. In the annular gap between the circulation tube 21 and the partition wall 20, the sewage flows downwards. At the lower end of the annular gap, a part of the downwardly directed sewage stream is deflected back into the' circulation tube 21. The remaining part of the sewage stream passes into the settling tank 8. The bio-sludge is sucked in by the settling tank 8 by means of the nozzles 3 and 4, (or, if appropriate, by means of a pump) and partially returned into the reactor 1.
2~~~128 _8_ The second zone may also be provided with a fixed bed 22 in the form of a fill or an ordered pack. The fixed bed 22 has the effect of immobilising the micro-organisms contained in the sewage and increasing their concentration in this zone. In order that the sewage circulation in the second zone is not excessively damped by the fixed bed 22, the said bed is preferably only arranged in the annular gap between partition wall 20 and circulation tie 21, as can be seen from Fig. 7.
By increasing the concentration of microorganisms in the second zone by means of the fixed bed 22, the requirement for bio-sludge to be returned from the settling tank 8 can be dispensed with completely.
In the case of the apparatuses according to Figs. 6 and 7, the nozzles 3 and 4 can be fitted to the reactor 1 at the bottom. However, they may also be arranged at the top, as emerges in principle from Figs. 1, 2 and 4.
Claims (18)
1. Process for the biological purification of sewage, with which sewage, containing dissolved pollutants, and air are introduced together under pressure via at least one nozzle into a reactor designed as a tank and are passed on in the reactor as a two-substance mixture, characterized - in that the sewage (AW) and the air (LT) are fed to the reactor (1) via at least two mutually separate nozzles (3, 4), - in that the streams of the two-substance mixture emanating from the nozzles (3, 4) are conducted in the reactor (1) such that they make impact with each other in the said reactor in an impact zone (PZ) and, - in that the sewage (AW) is passed after decomposition from the reactor (1) into a settling tank (8).
2. Process according to Claim 1, characterized in that a part of the sludge settling in the settling tank (8) is returned into the reactor (1) via the nozzles (3, 4).
3. Process according to Claim 1 or 2, characterized in that the throughput of sewage (AW) and air (LT) is evenly divided between the nozzles (3, 4).
4. Process according to one of Claims 1 to 3, characterized in that two-substance nozzles are used as nozzles (3, 4).
5. Process according to one of Claims 1 to 4, characterized in that the streams emanating from the nozzles (3, 4) are conducted such they make impact with each other frontally in the reactor (1).
6. Process according to one of Claims 1 to 5, characterized in that the streams are fed to the reactor (1) via conduit tubes (5, 6).
7. Process according to one of Claims 1 to 6, characterized in that the two-substance mixture is partially removed from the reactor (1) and fed once again to the said reactor via the nozzles (3, 4).
8. Process according to one of Claims 1 to 7, characterized in that the two-substance mixture in the reactor (1) is partially conducted in an internal circuit.
9. Process according to one of Claims 1 to 8, characterized in that sewage (AW) and air (LT) are fed to the reactor (1) from above.
10. Process according to one of Claims 1 to 8, characterized in that sewage (AW) and air (LT) are fed to the reactor (1) from below.
11. Apparatus for carrying out the process according to one of Claims 1 to 10, characterized by the use of a reactor (1) which has a compartment (2), arranged at its upper end in the position for use, at least two conduit tubes (5, 6), which end approximately in the central region of the reactor (1) at the same height in the said reactor, and at least two nozzles (3, 4), which project into the conduit tubes (5, 6) at the ends of the said tubes remote from the reactor (1), and a settling tank (8), connected to the reactor (1).
12. Apparatus according to Claim 11, characterized in that at least one weir (11), running vertically in the position for use of the apparatus, is fitted in the compartment (2).
13. Apparatus according to Claim 11 or 12, characterized in that the reactor (1) is dimensioned long enough for a decomposition of sewage (AW) and air (LT) to take place in its lower region.
14. Apparatus according to one of Claims 11 to 13, characterized in that geometry and dimensions of the nozzles (3, 4) are identical.
15. Apparatus according to one of Claims 11 to 14, characterized in that reactor (1) and settling tank (8) are combined into one unit.
16. Apparatus according to one of Claims 11 to 15, characterized in that at least one rotating partition wall (20) for the separation of two-substance mixture and purified waste water is fitted in the settling tank (8).
17. Apparatus according to one of Claims 11 to 16, characterized in that the settling tank (8) is arranged in the upper region of the reactor (1) as an extension of the said reactor and in that a circulation tube (21), for receiving two-substance mixture rising from the reactor (1), is fitted in the settling tank (8).
18. Apparatus according to one of Claims 11 to 17 characterized in that a fixed bed (22) of a fill or an ordered pack is arranged around the circulation tube (21).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3838846.4 | 1988-11-17 | ||
| DE19883838846 DE3838846A1 (en) | 1988-11-17 | 1988-11-17 | METHOD AND DEVICE FOR BIOLOGICAL WASTE WATER TREATMENT |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2003128A1 CA2003128A1 (en) | 1990-05-17 |
| CA2003128C true CA2003128C (en) | 2000-08-15 |
Family
ID=6367312
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2003128 Expired - Fee Related CA2003128C (en) | 1988-11-17 | 1989-11-16 | Process and apparatus for the biological purification of sewage |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0369455B1 (en) |
| JP (1) | JPH0667514B2 (en) |
| AT (1) | ATE74885T1 (en) |
| AU (1) | AU618642B2 (en) |
| CA (1) | CA2003128C (en) |
| DE (2) | DE3838846A1 (en) |
| ES (1) | ES2031340T3 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2951654A1 (en) * | 2009-08-11 | 2011-04-29 | Mohamed Rhouma | Oxidating and contacting fluids for biological treatment of wastewater, comprises simultaneously injecting two fluids in two pipes, mixing fluids in an impact zone, and passing the mixture of fluids to outer body of reactor |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4434540C2 (en) * | 1994-09-27 | 1997-07-31 | Hans Dieter Voelk | Process for aerobic high-performance wastewater treatment under pressure and strong dynamics and device for carrying out the process |
| FR2838067B1 (en) * | 2002-04-04 | 2005-02-04 | Toulouse Inst Nat Polytech | METHOD OF CONTACTING PHASES, IN PARTICULAR GAS / LIQUID, REACTOR RELATED TO MULTIDIRECTIONAL IMPACTS, AND APPLICATION TO OXIDIZING WATER TREATMENT |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5915005B2 (en) * | 1979-10-17 | 1984-04-07 | コニカ株式会社 | Distribution method |
| US4695378A (en) * | 1984-11-07 | 1987-09-22 | The United States Of America As Represented By The Secretary Of The Interior | Acid mine water aeration and treatment system |
| US4956080A (en) * | 1987-08-03 | 1990-09-11 | Microlift Systems, Incorporated | High pressure oxygen-saturated water treatment apparatus |
-
1988
- 1988-11-17 DE DE19883838846 patent/DE3838846A1/en active Granted
-
1989
- 1989-11-16 CA CA 2003128 patent/CA2003128C/en not_active Expired - Fee Related
- 1989-11-16 AU AU44763/89A patent/AU618642B2/en not_active Ceased
- 1989-11-17 JP JP29775489A patent/JPH0667514B2/en not_active Expired - Fee Related
- 1989-11-17 AT AT89121254T patent/ATE74885T1/en not_active IP Right Cessation
- 1989-11-17 EP EP19890121254 patent/EP0369455B1/en not_active Expired - Lifetime
- 1989-11-17 ES ES89121254T patent/ES2031340T3/en not_active Expired - Lifetime
- 1989-11-17 DE DE8989121254T patent/DE58901180D1/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2951654A1 (en) * | 2009-08-11 | 2011-04-29 | Mohamed Rhouma | Oxidating and contacting fluids for biological treatment of wastewater, comprises simultaneously injecting two fluids in two pipes, mixing fluids in an impact zone, and passing the mixture of fluids to outer body of reactor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0667514B2 (en) | 1994-08-31 |
| ES2031340T3 (en) | 1992-12-01 |
| DE3838846C2 (en) | 1993-09-09 |
| DE3838846A1 (en) | 1990-05-23 |
| JPH02237697A (en) | 1990-09-20 |
| AU618642B2 (en) | 1992-01-02 |
| AU4476389A (en) | 1990-05-24 |
| EP0369455B1 (en) | 1992-04-15 |
| DE58901180D1 (en) | 1992-05-21 |
| EP0369455A1 (en) | 1990-05-23 |
| CA2003128A1 (en) | 1990-05-17 |
| ATE74885T1 (en) | 1992-05-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |