CA2066212A1 - Process and device for treating, in particular cleaning, water containing halogenated ethylenes - Google Patents
Process and device for treating, in particular cleaning, water containing halogenated ethylenesInfo
- Publication number
- CA2066212A1 CA2066212A1 CA002066212A CA2066212A CA2066212A1 CA 2066212 A1 CA2066212 A1 CA 2066212A1 CA 002066212 A CA002066212 A CA 002066212A CA 2066212 A CA2066212 A CA 2066212A CA 2066212 A1 CA2066212 A1 CA 2066212A1
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- Prior art keywords
- water
- ozone
- irradiation
- electron
- chamber
- Prior art date
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Classifications
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- 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
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
- C02F1/78—Treatment of water, waste water, or sewage by oxidation with ozone
-
- 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
- C02F1/30—Treatment of water, waste water, or sewage by irradiation
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- Water Supply & Treatment (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Toxicology (AREA)
- Health & Medical Sciences (AREA)
- Physical Water Treatments (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
- Detergent Compositions (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Abstract:
The invention relates to a process and an apparatus for the treatment, in particular the purification, of waters, preferably ground water, containing halogenated ethylenes, for the use and consumption by humans and animals,the waters being subjected to exposure to ozone and high-energy, in particular ionizing, irradiation during flow. The invention is characterized in that a body of water, in particular ground water, essentially brought to or having drinking water properties in regard to the components and/or contaminants present, with the exception of the aforementioned halogenated ethylenes and containing ozone from a previous treatment and/or to which ozone was added, is exposed to electron irradiation during flow, the ozone concentration in the water being or being adjusted in such a manner that essentially immediately after discharge from the irradiation exposure zone, the ozone concentration in the water amounts to at least 0.1 ppm.
The invention relates to a process and an apparatus for the treatment, in particular the purification, of waters, preferably ground water, containing halogenated ethylenes, for the use and consumption by humans and animals,the waters being subjected to exposure to ozone and high-energy, in particular ionizing, irradiation during flow. The invention is characterized in that a body of water, in particular ground water, essentially brought to or having drinking water properties in regard to the components and/or contaminants present, with the exception of the aforementioned halogenated ethylenes and containing ozone from a previous treatment and/or to which ozone was added, is exposed to electron irradiation during flow, the ozone concentration in the water being or being adjusted in such a manner that essentially immediately after discharge from the irradiation exposure zone, the ozone concentration in the water amounts to at least 0.1 ppm.
Description
A Process and an Apparatus for Treating, in Particular for Purifying, Water that Contains Halogenated Ethylenes The present invention relates to a process for treating, in particular for purifying, water that contains halogenated ethylenes, in particular ground water, for the use and/or enjoyment of humans and animals, as well as apparatuses used for carrying out the process.
To an ever greater degree, environmental changes and increasing contamination of ground water are endangering water that, in the form of ground water, feeds wells and springs, or which has been obtained from static or flowing surface water and is intended for the use and enjoyment of humans as well as for animals and plants. In recent years, contamination of the waters described above by halogenated hydrocarbons, in particular by trichlorethylene and perchlorethylene, and occasionally by dichlorethylene, caused by the careless use of solvents in business, industry and households, has become a problem that is rapidly growing more serious; as has been seen, this problem can only be solved to an unsatisfactory degree by using existing methods that are suitable for large throughput rates.
The adsorption of the above-discussed injurious substances on activated carbon is such a process, which can be used today for reducing the content of halogenated hydrocarbons in drinking water that is used to supply heavily populated areas to a level that is below the permissible maximum level. In addition to its frequent lack of effectiveness, an important disadvantage of this method is the fact that, during regeneration of the activated carbon, the injurious substances that are removed from the water are released unchanged and then have to be disposed of separately.
In the search for effective methods, it has been found that treating the contaminated water with oxidants such as j r~ ~ ,? ~
chlorine, hydrogen peroxide, or ozone can, for all practical purposes, contribute nothing to any significant decomposition of the halogenated olefins. Other investigations, in which waters polluted in this manner were subjected to a combined treatment with ozone and ultraviolet light, as described by G.Peyton and W. Glaze in Environ.
Sci. Technol. 22:761-767 (1988), showed that their capacity is much too low for treatment of the throughput volume required for water supply. The treatment of waters containing polychlorinated biphenyls, also by means of ultraviolet irradiation in the presence of ozone is known from Chemical Abstracts 95(1981)29749y. But as the decomposition of aromatic compounds of this type is different from that of halogenated olefins, a prediction as to the effectiveness of this method for a decomposition of halogen olefins which occurs via different intermediaries and radicals is not possible; added to this are the aforementioned drawbacks in respect of throughput volumes.
The method according to W085/04160, which is also based on the use of ultraviolet irradiation combined with ozone, is directed to the decomposition of solids such as resins containing radioactive contaminants. In that case, the decomposition takes place after first suspending the solid in water at a comparatively high concentration. This publication does not offer a solution of the constellation of problems of a degradation of the entirely different halogen olefins present in natural waters in very low concentrations. Experiments with irradiation on a scientific basis show that although useful degrees of degradation were obtained, the periods required therefor were too long due to the low dose rate and only low throughputs were possible in this case, as well, as described in the publication of Gehringer et al. Z.Wasser-Abwasser-Forsch.19:196-203 (1986).
In experiments with treatment of contaminated waters by electron irradiation, it was found that as compared to irradiation, much higher irradiation doses are required for a certain percentage of decomposition of halogenated ~
hydrocarbons.
In investigations on the effect of ~-irradiation combined with ozone, such as they have been described , for instance, by Gehringer et al. in Water Res. 22: 645-646(1988), an essential increase of the degradation rate of halogenated olefins was observed, although it is still not possible to develop technical processes for water treatment on the basis of the effect observed in these investigations.
It was the object of the invention to develop a process for the treatment of waters contaminated by halogenated olefins which permits an effective decrease of these contaminants in the waters at the large throughput volumes usual for water supply and less expenditure in comparison to the decontamination by means of activated carbon previously described.
It was surprisingly found that on exposure to electron irradiation at simultaneous maintenance of given ozone concentrations in the water to be treated, high decomposition rates with throughputs increased by several orders of magnitude as compared to exposure to other types of rays and ozone are obtainable.
Object of the invention is thus a process of the type initially mentioned wherein the waters are subjected to the effect of ozone and high energy, in particular ionizing, irradiation which consists in that a body of water, in particular ground water, essentially brought to or having drinking water properties in regard to the components and/or contaminants present, with the exception of the aforementioned halogenated ethylenes and containing ozone from a previous treatment and/or to which ozone was added, is exposed to electron irradiation preferably during flow, the ozone content of the water being kept at a value of at least 0.1 ppm in the entire area of electron irradiation exposure.
As to the mechanism of action of electron irradiation in the presence of ozone, it is to be noted that halogenated olefins virtually do not react directly with ozone, and that instead their decomposition takes place by the action of OH
radicals formed of the water to be treated and by reaction of certain water radiolysis products with ozone. The advantage of electron irradiation in the presence of ozone is that in decomposition of the halogenated olefins to completely biocompatible substances, such as mainly carbonic acid and chloride ions, a subsequent disposal of the contaminants separated from the water, such as it is necessary in the process using activated carbon, is not required.
It was found that keeping within the aforementioned minimum concentration of ozone is conveniently facilitated according to a favorable variant of the process by adjusting the concentration of ozone in the water to be treated on entering the electron irradiation exposure area to a minimum of 1 ppm, preferably between 1 ppm and 10 PPM.
For achieving the throughputs necessary for water supply systems, it is technically convenient to subject the water containing ozone to an electron irradiation of an energy of at least 0.5 MeV. At this minimum energy, the penetration depth of radiation into the water amounts to 1.4 mm, which combined with an appropriate selection of conditions in plant geometry permits throughputs adequate for a sufficient supply.
The new process is particularly suitable for those low concentration ranges where a conventional decomposition would take too long due to high degrees of dilution. At concentrations of chlorinated olefins of essentially less than about 1 ppm, it was even possible to observe an acceleration of the extent of decomposition as compared to higher values.
To an ever greater degree, environmental changes and increasing contamination of ground water are endangering water that, in the form of ground water, feeds wells and springs, or which has been obtained from static or flowing surface water and is intended for the use and enjoyment of humans as well as for animals and plants. In recent years, contamination of the waters described above by halogenated hydrocarbons, in particular by trichlorethylene and perchlorethylene, and occasionally by dichlorethylene, caused by the careless use of solvents in business, industry and households, has become a problem that is rapidly growing more serious; as has been seen, this problem can only be solved to an unsatisfactory degree by using existing methods that are suitable for large throughput rates.
The adsorption of the above-discussed injurious substances on activated carbon is such a process, which can be used today for reducing the content of halogenated hydrocarbons in drinking water that is used to supply heavily populated areas to a level that is below the permissible maximum level. In addition to its frequent lack of effectiveness, an important disadvantage of this method is the fact that, during regeneration of the activated carbon, the injurious substances that are removed from the water are released unchanged and then have to be disposed of separately.
In the search for effective methods, it has been found that treating the contaminated water with oxidants such as j r~ ~ ,? ~
chlorine, hydrogen peroxide, or ozone can, for all practical purposes, contribute nothing to any significant decomposition of the halogenated olefins. Other investigations, in which waters polluted in this manner were subjected to a combined treatment with ozone and ultraviolet light, as described by G.Peyton and W. Glaze in Environ.
Sci. Technol. 22:761-767 (1988), showed that their capacity is much too low for treatment of the throughput volume required for water supply. The treatment of waters containing polychlorinated biphenyls, also by means of ultraviolet irradiation in the presence of ozone is known from Chemical Abstracts 95(1981)29749y. But as the decomposition of aromatic compounds of this type is different from that of halogenated olefins, a prediction as to the effectiveness of this method for a decomposition of halogen olefins which occurs via different intermediaries and radicals is not possible; added to this are the aforementioned drawbacks in respect of throughput volumes.
The method according to W085/04160, which is also based on the use of ultraviolet irradiation combined with ozone, is directed to the decomposition of solids such as resins containing radioactive contaminants. In that case, the decomposition takes place after first suspending the solid in water at a comparatively high concentration. This publication does not offer a solution of the constellation of problems of a degradation of the entirely different halogen olefins present in natural waters in very low concentrations. Experiments with irradiation on a scientific basis show that although useful degrees of degradation were obtained, the periods required therefor were too long due to the low dose rate and only low throughputs were possible in this case, as well, as described in the publication of Gehringer et al. Z.Wasser-Abwasser-Forsch.19:196-203 (1986).
In experiments with treatment of contaminated waters by electron irradiation, it was found that as compared to irradiation, much higher irradiation doses are required for a certain percentage of decomposition of halogenated ~
hydrocarbons.
In investigations on the effect of ~-irradiation combined with ozone, such as they have been described , for instance, by Gehringer et al. in Water Res. 22: 645-646(1988), an essential increase of the degradation rate of halogenated olefins was observed, although it is still not possible to develop technical processes for water treatment on the basis of the effect observed in these investigations.
It was the object of the invention to develop a process for the treatment of waters contaminated by halogenated olefins which permits an effective decrease of these contaminants in the waters at the large throughput volumes usual for water supply and less expenditure in comparison to the decontamination by means of activated carbon previously described.
It was surprisingly found that on exposure to electron irradiation at simultaneous maintenance of given ozone concentrations in the water to be treated, high decomposition rates with throughputs increased by several orders of magnitude as compared to exposure to other types of rays and ozone are obtainable.
Object of the invention is thus a process of the type initially mentioned wherein the waters are subjected to the effect of ozone and high energy, in particular ionizing, irradiation which consists in that a body of water, in particular ground water, essentially brought to or having drinking water properties in regard to the components and/or contaminants present, with the exception of the aforementioned halogenated ethylenes and containing ozone from a previous treatment and/or to which ozone was added, is exposed to electron irradiation preferably during flow, the ozone content of the water being kept at a value of at least 0.1 ppm in the entire area of electron irradiation exposure.
As to the mechanism of action of electron irradiation in the presence of ozone, it is to be noted that halogenated olefins virtually do not react directly with ozone, and that instead their decomposition takes place by the action of OH
radicals formed of the water to be treated and by reaction of certain water radiolysis products with ozone. The advantage of electron irradiation in the presence of ozone is that in decomposition of the halogenated olefins to completely biocompatible substances, such as mainly carbonic acid and chloride ions, a subsequent disposal of the contaminants separated from the water, such as it is necessary in the process using activated carbon, is not required.
It was found that keeping within the aforementioned minimum concentration of ozone is conveniently facilitated according to a favorable variant of the process by adjusting the concentration of ozone in the water to be treated on entering the electron irradiation exposure area to a minimum of 1 ppm, preferably between 1 ppm and 10 PPM.
For achieving the throughputs necessary for water supply systems, it is technically convenient to subject the water containing ozone to an electron irradiation of an energy of at least 0.5 MeV. At this minimum energy, the penetration depth of radiation into the water amounts to 1.4 mm, which combined with an appropriate selection of conditions in plant geometry permits throughputs adequate for a sufficient supply.
The new process is particularly suitable for those low concentration ranges where a conventional decomposition would take too long due to high degrees of dilution. At concentrations of chlorinated olefins of essentially less than about 1 ppm, it was even possible to observe an acceleration of the extent of decomposition as compared to higher values.
2~
It is thus preferab:Le to expose water with a content in halogenated ethylenes of up to 1,000 ppb to the action of ozone and electron irradiation If, as is provided by another advantageous embodiment of the present invention, in order to maintain the cited minimum concentration of 0.1 ppm ozone, additional ozone, preferably in the form of contaminated water that has been enriched with ozone, is added to the water that is in through-flow, this being done directly in the area in which the electron irradiation is effective, preferably transversely to the direction of flowthrough, the contents of halogenated olefins can be effectively reduced or eliminated in water that contains large quantities of bicarbonates and nitrates.
As has been found, a particularly favourable exploitation of the synergism between electron irradiation and ozone content can be achieved by the use of a through-flow chamber, the height of which is greater that the penetration depth of the electrons, if the volumetric fraction of the water that is flowing through the through-flow chamber, which is directed against the penetrating electron irradiation, is mixed very thoroughly with its remaining volumetric fraction, preferably by causing a turbulent flow.
By this means, it iæ possible to achieve an expansion of the decomposition of the injurious substances from the volumetri~ fraction that is close to the source of the radiation to the whole of the effective area. By doing this, it is possible to achieve a significant increase of the throughput or, if this is not required, it is possible to manage with much less power, by using an electron accelerator.
According to another advantageous variant of the ~?~
present process, one can proceed such that essentially in the whole effective are~ of the electron irradiation, the content of dissolved ozone in the water is kept to a value of at least 0.1 ppm.
An additional object of the present invention is an embodiment of an apparatus for carrying out the process described above, with respect to optimal use of the electron irradiation. At this point, it should be noted that DE-A 25 46 756 describes an apparatus for a completely different purposes, namely for sterilizing sewage sludge, said apparatus incorporating a delivery trough for the sludge, the base of this being formed, in the irradiation area of a source of electron radiation that is located above it, as a nozzle base for the introduction of a gas that contains oxygen, a device for feeding in the sludge in a layer of even thickness being incorporated in the apparatus.
The apparatus according to the present invention, which has at least one electron accelerator and at least one irradiation chamber that is located within the effective irradiation cone of this, and which incorporates inlet and outlet lines for a fluid medium and through which said fluid medium flows and which, preferably on its side that is remote from the effect of the irradiation, incorporates openings for the introduction of a fluid medium that contains ozone, is characterized in that essentially at the beginning of outlet line that is connected to the through-flow chamber through which the water that contains the halogenated ethylenes flows, there is a sensor that is used to determine the ozone content and that is connected through a control unit to at least one servo-element for at least one feed regulating element of at least one contaminated water feed line.
Using this apparatus, it is possible to regulate the ozone content within the through-flow chamber very precisely and economically. The sensor can, for example, be in the 2~?~i~ 2 form of a through-flow cell of an ultraviolet spectral photometer that is incorporated in a by-pass that branches off from the outlet line of the through-flow chamber.
A further object of the present invention is the use of an apparatus as described above, wit:h at least one electron accelerator and with at least one irradiation chamber that is located within the effective cone of this, and which incorporates inlet and outlet lines for a fluid medium and through which said fluid medium flows, which, preferably on its side that is remote from the effect of the irradiation, incorporates openings for the introduction of a fluid medium that contains ozone, provided, however, that the water that contains the halogenated ethylenes flows through the chamber and that contaminated water that has been enriched with ozone and/or ozone [alons] is introduced into this through the openings discussed above, there being a sensor to determine the ozone content arranged essentially at the beginning of the outlet line that is connected to the through-flow chamber, this sensor being connected through a control unit with at least one servo-elèment for at least one feed regulating element, at least of one feed line, for contaminated water to the openings, for treating, in particular for purifying, water that contains halogenated ethylenes and which is intended for the use and/or enjoyment of humans and animals, according to the process described above and preferred embodiments thereof.
In order to ensure the particularly even maintenance of the ozone concentration in the contaminated water that is to be subjected to the electron irradiation, an advantageous manner of use foresees that the side of the chamber that is remote from the electron irradiation is configured, at least in part, as a sieve base or frit.
When this is done, according to a variant that is of relatively simple construction but which, as has been shown, meets all the demands for the desired high level of ;~?6~
decomposition, it can be advantageous if the base of the chamber, essentially in the area of half of the through-flow section of the water incorpora~es at least one row of openings or nozzles for the introduction of contaminated water that is enriched with ozone and/or ozone [alone], this row of openings or nozzles being transverse to the direction of flow.
An increase in the degree of exploitation of the electron irradiation and of the ozone that is introduced can be achieved by using an apparatus in which, in addition or alternatively to the configuration of the base as a sieve base or frit, there are elements to generate a turbulent flow built into the irradiation chamber.
With an arrangement like this, the water flowing through the chamber previously described can be present in a layer thickness essentially exceeding the penetration depth of electron irradiation even at low penetration depth.
The invention is explained in detail on the basis of the following example.
Example:
To two different bodies of water A and B, namely from the water supply of Vienna and spring water frGm a rural area (Bucklige Welt) whose composition is evident from Table 1, tetrachloroethylene and trichloroethylene were added in the starting concentrations indicated in column 1 of Table 2.
Table 1 . total HC03- _ Cl S04 Hardneg 9 ppm ppm ppm ppm Water A 9 . 6 195 6. 5 4. 5 31 Water B 9 . 5 99 4 5 21 ~ ?~ ~
By means of ~-ray source (Co-60) with a dose rate of approximately 1.5 Gy/s (= Gray/second) and by means of an 0.5 MeV electron accelerator essentially corresponding to the diagram of the system represented in the drawing, the bodies of water A and B were irradiated at a water temperature of 10C with the concentrations of chlorinated ethylenes indicated above, the irradiation in each case being carried out with and without the addition of ozone, at concentration of about 3 ppm of 03 for waters A and B
containing trichloroethylene and about 5 ppm of 03 for waters A and B containing tetrachloroethylene.
The degrees of decomposition of 90, 95 and 99 percent determined in these investigations are evident from columns 3,5,7 and 9 of Table 2.
On the basis of these experimentally determined dose values, maximum obtainable throughputs in M3/h were calculated, on the assumption that a technically still feasible Co-60 gamma ray source with 1 MCi Co-60 activity corresponding to a rate of about 13Kw and an electron ray source in the form of a technically conventional electron accelerator in the higher rate range with an energy of 3 MeV
and a beam current of 50 m~, corresponding to a rate of 150 kW would be available for irradiation. The corresponding data are contained in columns 4,6,8 and 10.
A comparison of the dose values obtained for the various samples of waters A and B shows the unexpected effect of the decomposition of contaminants by means of electron irradiation combined with ozone.
It is evident that in the absence of ozone in the waters when using electron irradiation at identical degrees of decomposition, in particular where these increase, substantially higher doses than when using gamma irradiation are required, as for instance for decomposition of 90 and 99 _ 10 --Tab~e 2:
--3 14 1 5 i 6 7 18 ~ 19 11 5 h~/ Degree ~- :~ Elec~n l~;i~
Ccn of Oegra ~tl~ut 03 ~,LLth 03 h~Lt~t 03 h~th 03 tard~ dati~n d~;e dose thrw~ dose ~ dose ;~
% put put put put Gy m3/h Gy m3/h Gy m3/h Gy m3/h 10 ~-- ~ _ _ _ _ hbt~ A 90 185 253 50 936 390 ~ 48 11~50 100 ppb 95 240 195 65 720 600 9C0 68 7~41 tetra . 99 370 126 100 468 ~220 443 1~6 5143 15 etiyl~e h~rter A 90~DO 468 10 4680 205 2634 9 60000 100 ppb 95130 3~0 20 2~40 385 1403 21 . 25714 t;~ am 99195 240 60 780 1~0 514 60 90~0 20 etlyl~e .
l~t~ B 9096 487 14 3343 135 4000 15 36000 - 100 ppb 95~5 374 25 1872 190 2842 25 216C0 tet~ 991~3 242 50 936 425 1270 52 1~385 25d~
h~ter B 9058 807 9 5200 90 6~0 10 54000 100 ppb 9575 624 11 4255 160 3375 11 490~0 30 tr~ar~ 99 115 407 20 2340 425 1270 22 24545 e~e ~ _ percent, the doses on using electron irradiation as compared to those of gamma radiation increase by a factor of about 2 to about 4 to 5. It was surprisingly found that in the presence of ozone, the doses obtained by using electron irradiation were virtually identical to those obtained by using gamma irradiation. The concerted use of ozone thus permits decomposition rates of contaminants by means of electron irradiation which are equal to those obtained by means of gamma rays.
The throughput values computed in support of the significance of these results for practice show that the throughputs obtainable by using electron irradiation combined with ozone are about five to twelve times as high as those obtainable by means of gamma irradiation combined with ozone.
The drawing serving for the further explanation of the invention shows a diagrammatic representation of a preferred embodiment of a plant provided for carrying out the new process with particular emphasis placed on the flow chamber to be exposed to electron irradiation.
In the plant diagrammatically represented in the drawing and serving for the treatment of waters contaminated with chlorinated olefins, a main stream of the water containing the contaminants is fed via line 1, a buffer container 2 and a pump 3, a partial stream of the water being fed from container 2 via a branch line 5 by means of pump 6 into a container with ozone and strong water and a mixer 7 which is in turn supplied via line 10 with ozone from the ozonizer 9 fed with oxygen via a line 8. In the container 7, "strong water" enriched in ozone is produced and conveyed via line 11 to that for still untreated starting water via the aforementioned line 1, whereupon the united streams 1 and 11 are intimately mixed in the mixer 13 for adjusting a desired starting concentration of ozone. The ozone-containing water thus obtained and to be ;X~ 2 decontaminated is fed via line 14 into flow chamber 15 with electron-permeable window 151 disposed underneath an electron accelerator 17 with exposure area 171, the water flows through the chamber and is exposed to electron irradiation in area 171. Approximately at half of the flow path, the bottom 155 of the chamber 15 is provided with a row of nozzle orifices 153 communicating with an inlet channel 154 and serving for assuring a minimum concentration of ozone in the chamber 15 by means of a partial stream 111 branching off from the strong water line 11 and leading directly into the irradiation chamber 15. Chamber 15 is provided with elements such as baffle plates 152 for increasing the effect by generating turbulent flow. In the chamber 15, the chlorinated ethylenes are decomposed to biocompatible substances due to the àforementioned synergism between electron radiation and ozone. The treated water now present in the chamber 15 is discharged via a line 18 provided with a balance vessel 19 and can be directly fed into a water supply system. The flow regulating organs 4, 12 and 16 represented in the drawing serve for a mutually adapted adjustment of the streams of water to be treated and ozonized strong water.
It is thus preferab:Le to expose water with a content in halogenated ethylenes of up to 1,000 ppb to the action of ozone and electron irradiation If, as is provided by another advantageous embodiment of the present invention, in order to maintain the cited minimum concentration of 0.1 ppm ozone, additional ozone, preferably in the form of contaminated water that has been enriched with ozone, is added to the water that is in through-flow, this being done directly in the area in which the electron irradiation is effective, preferably transversely to the direction of flowthrough, the contents of halogenated olefins can be effectively reduced or eliminated in water that contains large quantities of bicarbonates and nitrates.
As has been found, a particularly favourable exploitation of the synergism between electron irradiation and ozone content can be achieved by the use of a through-flow chamber, the height of which is greater that the penetration depth of the electrons, if the volumetric fraction of the water that is flowing through the through-flow chamber, which is directed against the penetrating electron irradiation, is mixed very thoroughly with its remaining volumetric fraction, preferably by causing a turbulent flow.
By this means, it iæ possible to achieve an expansion of the decomposition of the injurious substances from the volumetri~ fraction that is close to the source of the radiation to the whole of the effective area. By doing this, it is possible to achieve a significant increase of the throughput or, if this is not required, it is possible to manage with much less power, by using an electron accelerator.
According to another advantageous variant of the ~?~
present process, one can proceed such that essentially in the whole effective are~ of the electron irradiation, the content of dissolved ozone in the water is kept to a value of at least 0.1 ppm.
An additional object of the present invention is an embodiment of an apparatus for carrying out the process described above, with respect to optimal use of the electron irradiation. At this point, it should be noted that DE-A 25 46 756 describes an apparatus for a completely different purposes, namely for sterilizing sewage sludge, said apparatus incorporating a delivery trough for the sludge, the base of this being formed, in the irradiation area of a source of electron radiation that is located above it, as a nozzle base for the introduction of a gas that contains oxygen, a device for feeding in the sludge in a layer of even thickness being incorporated in the apparatus.
The apparatus according to the present invention, which has at least one electron accelerator and at least one irradiation chamber that is located within the effective irradiation cone of this, and which incorporates inlet and outlet lines for a fluid medium and through which said fluid medium flows and which, preferably on its side that is remote from the effect of the irradiation, incorporates openings for the introduction of a fluid medium that contains ozone, is characterized in that essentially at the beginning of outlet line that is connected to the through-flow chamber through which the water that contains the halogenated ethylenes flows, there is a sensor that is used to determine the ozone content and that is connected through a control unit to at least one servo-element for at least one feed regulating element of at least one contaminated water feed line.
Using this apparatus, it is possible to regulate the ozone content within the through-flow chamber very precisely and economically. The sensor can, for example, be in the 2~?~i~ 2 form of a through-flow cell of an ultraviolet spectral photometer that is incorporated in a by-pass that branches off from the outlet line of the through-flow chamber.
A further object of the present invention is the use of an apparatus as described above, wit:h at least one electron accelerator and with at least one irradiation chamber that is located within the effective cone of this, and which incorporates inlet and outlet lines for a fluid medium and through which said fluid medium flows, which, preferably on its side that is remote from the effect of the irradiation, incorporates openings for the introduction of a fluid medium that contains ozone, provided, however, that the water that contains the halogenated ethylenes flows through the chamber and that contaminated water that has been enriched with ozone and/or ozone [alons] is introduced into this through the openings discussed above, there being a sensor to determine the ozone content arranged essentially at the beginning of the outlet line that is connected to the through-flow chamber, this sensor being connected through a control unit with at least one servo-elèment for at least one feed regulating element, at least of one feed line, for contaminated water to the openings, for treating, in particular for purifying, water that contains halogenated ethylenes and which is intended for the use and/or enjoyment of humans and animals, according to the process described above and preferred embodiments thereof.
In order to ensure the particularly even maintenance of the ozone concentration in the contaminated water that is to be subjected to the electron irradiation, an advantageous manner of use foresees that the side of the chamber that is remote from the electron irradiation is configured, at least in part, as a sieve base or frit.
When this is done, according to a variant that is of relatively simple construction but which, as has been shown, meets all the demands for the desired high level of ;~?6~
decomposition, it can be advantageous if the base of the chamber, essentially in the area of half of the through-flow section of the water incorpora~es at least one row of openings or nozzles for the introduction of contaminated water that is enriched with ozone and/or ozone [alone], this row of openings or nozzles being transverse to the direction of flow.
An increase in the degree of exploitation of the electron irradiation and of the ozone that is introduced can be achieved by using an apparatus in which, in addition or alternatively to the configuration of the base as a sieve base or frit, there are elements to generate a turbulent flow built into the irradiation chamber.
With an arrangement like this, the water flowing through the chamber previously described can be present in a layer thickness essentially exceeding the penetration depth of electron irradiation even at low penetration depth.
The invention is explained in detail on the basis of the following example.
Example:
To two different bodies of water A and B, namely from the water supply of Vienna and spring water frGm a rural area (Bucklige Welt) whose composition is evident from Table 1, tetrachloroethylene and trichloroethylene were added in the starting concentrations indicated in column 1 of Table 2.
Table 1 . total HC03- _ Cl S04 Hardneg 9 ppm ppm ppm ppm Water A 9 . 6 195 6. 5 4. 5 31 Water B 9 . 5 99 4 5 21 ~ ?~ ~
By means of ~-ray source (Co-60) with a dose rate of approximately 1.5 Gy/s (= Gray/second) and by means of an 0.5 MeV electron accelerator essentially corresponding to the diagram of the system represented in the drawing, the bodies of water A and B were irradiated at a water temperature of 10C with the concentrations of chlorinated ethylenes indicated above, the irradiation in each case being carried out with and without the addition of ozone, at concentration of about 3 ppm of 03 for waters A and B
containing trichloroethylene and about 5 ppm of 03 for waters A and B containing tetrachloroethylene.
The degrees of decomposition of 90, 95 and 99 percent determined in these investigations are evident from columns 3,5,7 and 9 of Table 2.
On the basis of these experimentally determined dose values, maximum obtainable throughputs in M3/h were calculated, on the assumption that a technically still feasible Co-60 gamma ray source with 1 MCi Co-60 activity corresponding to a rate of about 13Kw and an electron ray source in the form of a technically conventional electron accelerator in the higher rate range with an energy of 3 MeV
and a beam current of 50 m~, corresponding to a rate of 150 kW would be available for irradiation. The corresponding data are contained in columns 4,6,8 and 10.
A comparison of the dose values obtained for the various samples of waters A and B shows the unexpected effect of the decomposition of contaminants by means of electron irradiation combined with ozone.
It is evident that in the absence of ozone in the waters when using electron irradiation at identical degrees of decomposition, in particular where these increase, substantially higher doses than when using gamma irradiation are required, as for instance for decomposition of 90 and 99 _ 10 --Tab~e 2:
--3 14 1 5 i 6 7 18 ~ 19 11 5 h~/ Degree ~- :~ Elec~n l~;i~
Ccn of Oegra ~tl~ut 03 ~,LLth 03 h~Lt~t 03 h~th 03 tard~ dati~n d~;e dose thrw~ dose ~ dose ;~
% put put put put Gy m3/h Gy m3/h Gy m3/h Gy m3/h 10 ~-- ~ _ _ _ _ hbt~ A 90 185 253 50 936 390 ~ 48 11~50 100 ppb 95 240 195 65 720 600 9C0 68 7~41 tetra . 99 370 126 100 468 ~220 443 1~6 5143 15 etiyl~e h~rter A 90~DO 468 10 4680 205 2634 9 60000 100 ppb 95130 3~0 20 2~40 385 1403 21 . 25714 t;~ am 99195 240 60 780 1~0 514 60 90~0 20 etlyl~e .
l~t~ B 9096 487 14 3343 135 4000 15 36000 - 100 ppb 95~5 374 25 1872 190 2842 25 216C0 tet~ 991~3 242 50 936 425 1270 52 1~385 25d~
h~ter B 9058 807 9 5200 90 6~0 10 54000 100 ppb 9575 624 11 4255 160 3375 11 490~0 30 tr~ar~ 99 115 407 20 2340 425 1270 22 24545 e~e ~ _ percent, the doses on using electron irradiation as compared to those of gamma radiation increase by a factor of about 2 to about 4 to 5. It was surprisingly found that in the presence of ozone, the doses obtained by using electron irradiation were virtually identical to those obtained by using gamma irradiation. The concerted use of ozone thus permits decomposition rates of contaminants by means of electron irradiation which are equal to those obtained by means of gamma rays.
The throughput values computed in support of the significance of these results for practice show that the throughputs obtainable by using electron irradiation combined with ozone are about five to twelve times as high as those obtainable by means of gamma irradiation combined with ozone.
The drawing serving for the further explanation of the invention shows a diagrammatic representation of a preferred embodiment of a plant provided for carrying out the new process with particular emphasis placed on the flow chamber to be exposed to electron irradiation.
In the plant diagrammatically represented in the drawing and serving for the treatment of waters contaminated with chlorinated olefins, a main stream of the water containing the contaminants is fed via line 1, a buffer container 2 and a pump 3, a partial stream of the water being fed from container 2 via a branch line 5 by means of pump 6 into a container with ozone and strong water and a mixer 7 which is in turn supplied via line 10 with ozone from the ozonizer 9 fed with oxygen via a line 8. In the container 7, "strong water" enriched in ozone is produced and conveyed via line 11 to that for still untreated starting water via the aforementioned line 1, whereupon the united streams 1 and 11 are intimately mixed in the mixer 13 for adjusting a desired starting concentration of ozone. The ozone-containing water thus obtained and to be ;X~ 2 decontaminated is fed via line 14 into flow chamber 15 with electron-permeable window 151 disposed underneath an electron accelerator 17 with exposure area 171, the water flows through the chamber and is exposed to electron irradiation in area 171. Approximately at half of the flow path, the bottom 155 of the chamber 15 is provided with a row of nozzle orifices 153 communicating with an inlet channel 154 and serving for assuring a minimum concentration of ozone in the chamber 15 by means of a partial stream 111 branching off from the strong water line 11 and leading directly into the irradiation chamber 15. Chamber 15 is provided with elements such as baffle plates 152 for increasing the effect by generating turbulent flow. In the chamber 15, the chlorinated ethylenes are decomposed to biocompatible substances due to the àforementioned synergism between electron radiation and ozone. The treated water now present in the chamber 15 is discharged via a line 18 provided with a balance vessel 19 and can be directly fed into a water supply system. The flow regulating organs 4, 12 and 16 represented in the drawing serve for a mutually adapted adjustment of the streams of water to be treated and ozonized strong water.
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:-
1. A process for treating, in particular for purifying, water, preferably ground water, that contains halogenated ethylenes, and which is intended for the use and/or enjoyment of humans and animals, said water being subjected to the effect of ozone and energy-rich, in particular ionizing, radiation, characterized in that water, particularly ground water, that with respect to the existing constituents and/or injurious substances, apart from the above-named halogenated ethylenes, has been essentially been brought to the same quality as drinking water, or water that contains these, and to which water that contains ozone and/or water that has had ozone added to it separately, is exposed to the effects of electron irradiation in through-flow , the ozone concentration in the water having been adjusted, or being adjusted, such that the water essentially has an ozone concentration of at least 0.1 ppm immediately after leaving the area in which this irradiation is effective.
2. A process as defined in claim 1, characterized in that the concentration of the ozone in the water that is to be treated is adjusted to a value of at least 1 ppm, and preferably between 1 and 10 ppm, immediately on entering the area in which the irradiation is effective.
3. A process as defined in claim 1 or claim 2, characterized in that the water that contains the ozone is exposed to electron irradiation with an energy level of at least 0.5 MeV.
4. A process as defined in one of the claims 1 to 3, characterized in that water with a content of halogenated ethylenes of a total of up to some 1000 ppb is subjected to the action of ozone and electron irradiation.
5. A process as defined in one of the claims 1 to 4, characterized in that in order to maintain the quoted minimum concentration of ozone, additional ozone, preferably in the form of contaminated water that has been enriched with ozone, is added to the water that is in through-flow, this being done directly in the area in which the electron irradiation is effective, preferably transversely to the direction of the through-flow.
6. A process as defined in one of the claims 1 to 5, characterized in that the volumetric fraction that faces the electron irradiation and that is flowing through the area in which this is effective is mixed very intensively with its residual volumetric fraction, preferably by the generation of turbulent flow.
7. A process as defined in one of the claims 1 to 6, characterized in that essentially in the whole area of the effect of the electron irradiation, the content of dissolved ozone in the water is maintained at a value of at least 0.1 ppm.
8. An apparatus for carrying out the process as defined in one of the claims 1 to 7, with at least one electron accelerator electron accelerator and at least one irradiation chamber that is located within the effective cone of this, and which incorporates inlet and outlet lines for a fluid medium and through which said fluid medium flows, which, preferably on its side that is remote from the effect of the irradiation, incorporates openings (153) for the introduction of a fluid medium that contains ozone, characterized in that essentially at the beginning of outlet line (18) that is connected to the through-flow chamber (15) through which the water that contains the halogenated ethylenes flows, there is a sensor (181) that is used to determine the ozone content and that is connected through a control unit (182) to at least one servo-element (121), (151) for at least one feed regulating element (12), (16) of at least one contaminated. water feed line (11, 111).
9. The use of an apparatus with at least one electron accelerator and with at least one irradiation chamber that is located within the effective cone of this, and which incorporates inlet and outlet lines for a fluid medium and through which said fluid medium flows, which, preferably on its side that is remote from the effect of the irradiation, incorporates openings for the introduction of a fluid medium that contains ozone, provided, however, that the water that contains the halogenated ethylenes passes through the chamber (15) and contaminated water that has been enriched with ozone and/or ozone [alone] is introduced into this through the openings (153), there being, essentially at the beginning of outlet line (18) that is connected to the through-flow chamber (15) through which the water that contains the halogenated ethylenes flows, a sensor (181) that is used to determine the ozone content and that is connected through a control unit (182) to at least one servo-element (121), (161) for at least one feed regulating element (12), (16) of at least one contaminated water feed line (11, 111), to the openings (153) for the processing, particularly the purification, of water that contains halogenated ethylenes, intended for the use and/or enjoyment of humans and animals, according to one of the claims 1 to 7.
10. The use of the apparatus described in claim 8, providing that the side (155) of the radiation chamber (15) that is remote from the effects of the irradiation incorporates a sieve base or frit for the introduction of contaminated water that has been enriched with ozone and/or elements to generate turbulent flow, for the purposes described in claim 9.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT1901/89A AT392462B (en) | 1989-08-08 | 1989-08-08 | METHOD AND DEVICE FOR TREATING, IN PARTICULAR CLEANING OF WATER CONTAINING HALOGENED ETHYLENE |
| ATA1901/89 | 1989-08-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2066212A1 true CA2066212A1 (en) | 1991-02-09 |
Family
ID=3523469
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002066212A Abandoned CA2066212A1 (en) | 1989-08-08 | 1990-07-13 | Process and device for treating, in particular cleaning, water containing halogenated ethylenes |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0494866B1 (en) |
| AT (2) | AT392462B (en) |
| CA (1) | CA2066212A1 (en) |
| DE (1) | DE59006378D1 (en) |
| ES (1) | ES2061049T3 (en) |
| HU (1) | HU216860B (en) |
| RU (1) | RU2080299C1 (en) |
| WO (1) | WO1991001946A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT399863B (en) * | 1993-08-17 | 1995-08-25 | Oesterr Forsch Seibersdorf | Process for reducing microorganisms and/or pathogenic microbes in waters, apparatus for carrying it out and use of the apparatus |
| AT405173B (en) * | 1996-06-21 | 1999-06-25 | Oesterr Forsch Seibersdorf | Process for treating waters polluted with at least one triazine derivative for drinking water purposes |
| AT407521B (en) * | 1998-01-21 | 2001-04-25 | Oesterr Forsch Seibersdorf | TREATMENT OF WATER CONTAINED WITH GENETIC SUBSTANCES |
| AU2000265603A1 (en) * | 2000-07-03 | 2002-01-14 | High Voltage Environmental Applications Deutschland Gmbh | Method and device for treating pumpable media contaminated with harmful substances |
| WO2016113807A1 (en) * | 2015-01-14 | 2016-07-21 | Hitachi Zosen Corporation | Electron beam sterilization equipment with a self-generated sterile-in-place unit |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2546756C3 (en) * | 1975-10-18 | 1978-11-09 | Werner & Pfleiderer, 7000 Stuttgart | Continuous process and device for killing pathogens in sewage sewage sludge |
| US4437999A (en) * | 1981-08-31 | 1984-03-20 | Gram Research & Development Co. | Method of treating contaminated insoluble organic solid material |
-
1989
- 1989-08-08 AT AT1901/89A patent/AT392462B/en not_active IP Right Cessation
-
1990
- 1990-07-13 DE DE59006378T patent/DE59006378D1/en not_active Expired - Lifetime
- 1990-07-13 AT AT90910488T patent/ATE108167T1/en not_active IP Right Cessation
- 1990-07-13 EP EP90910488A patent/EP0494866B1/en not_active Expired - Lifetime
- 1990-07-13 RU SU905011495A patent/RU2080299C1/en active
- 1990-07-13 HU HU9200144A patent/HU216860B/en unknown
- 1990-07-13 WO PCT/AT1990/000069 patent/WO1991001946A1/en active IP Right Grant
- 1990-07-13 CA CA002066212A patent/CA2066212A1/en not_active Abandoned
- 1990-07-13 ES ES90910488T patent/ES2061049T3/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| ATA190189A (en) | 1990-09-15 |
| WO1991001946A1 (en) | 1991-02-21 |
| HUT70354A (en) | 1995-10-30 |
| RU2080299C1 (en) | 1997-05-27 |
| DE59006378D1 (en) | 1994-08-11 |
| AT392462B (en) | 1991-04-10 |
| HU9200144D0 (en) | 1992-09-28 |
| ATE108167T1 (en) | 1994-07-15 |
| EP0494866A1 (en) | 1992-07-22 |
| ES2061049T3 (en) | 1994-12-01 |
| HU216860B (en) | 1999-09-28 |
| EP0494866B1 (en) | 1994-07-06 |
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| FZDE | Discontinued |