EP0950136B1 - Traitement a l'oxygene de filtrats issus d'usines de blanchiment - Google Patents

Traitement a l'oxygene de filtrats issus d'usines de blanchiment Download PDF

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Publication number
EP0950136B1
EP0950136B1 EP97952166A EP97952166A EP0950136B1 EP 0950136 B1 EP0950136 B1 EP 0950136B1 EP 97952166 A EP97952166 A EP 97952166A EP 97952166 A EP97952166 A EP 97952166A EP 0950136 B1 EP0950136 B1 EP 0950136B1
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EP
European Patent Office
Prior art keywords
pulp
residue liquid
bleaching
oxygen
part flow
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP97952166A
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German (de)
English (en)
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EP0950136A1 (fr
Inventor
Monica BOKSTRÖM
Peter Hardmeier
Björn JANSSON
Martin Petersson
Anna TIGERSTRÖM
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AGA AB
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AGA AB
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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/1026—Other features in bleaching processes
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C11/00—Regeneration of pulp liquors or effluent waste waters
    • D21C11/0021—Introduction of various effluents, e.g. waste waters, into the pulping, recovery and regeneration cycle (closed-cycle)
    • D21C11/0028—Effluents derived from the washing or bleaching plants
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C11/00—Regeneration of pulp liquors or effluent waste waters
    • D21C11/0057—Oxidation of liquors, e.g. in order to reduce the losses of sulfur compounds, followed by evaporation or combustion if the liquor in question is a black liquor

Definitions

  • the present invention refers to a method for the treatment of cellulose fibres in a pulp stream, comprising the steps of: preparing a pulp, subjecting the pulp to a bleaching, comprising at least one bleaching step, by the supply of an oxidizing bleaching agent, removing liquid from the pulp after the bleaching while obtaining a residue liquid, see EP-A-564443 and CA-A-2170553.
  • the residue liquid obtained forms, after having been conveyed in a counter flow to the pulp flow, an effluent flow which is conveyed to an effluent plant.
  • the effluent flow contains oxygen consuming organic substances, so called COD (chemical oxygen demand), which thus must only be contained in a determined quantity of tons per day in the effluent liquid leaving a pulp plant.
  • COD chemical oxygen demand
  • WO94/21857 discloses a method for removing metals from a filtrate obtained in a dewatering device in a pulp stream.
  • This document discloses the supply of an oxidizing agent, for instance oxygen gas, and alkali to the filtrate in a reactor.
  • an oxidizing agent for instance oxygen gas
  • alkali to the filtrate in a reactor.
  • the metals dissolved in the filtrate may be percipitated as solid particles and removed therefrom.
  • the Swedish patent application No 9601709-0 which corresponds to CA-A-2170553, discloses a method for the treatment of cellulose pulp along a pulp stream.
  • the cellulose pulp is bleached in several steps and a residue liquid is separated from the pulp and returned to the pulp stream. Before being returned, the residue liquid is brought into contact with an oxidation gas in a oxidation reactor.
  • the preferred oxidation gas is ozone.
  • EP-A-564443 discloses a method for the treatment of cellulose pulp along a pulp stream comprising bleaching in several steps.
  • a residue liquid is obtained after a bleaching step and returned to a prior washing step.
  • the residue liquid obtained is heated and conveyed to a reactor to react with oxygen gas. Thereafter, the residue liquid is conveyed to a heat exchanger and from there back to the pulp stream.
  • the object of the present invention is to provide a method for solving the problems mentioned above.
  • an object is to provide a residue liquid, in connection with pulp bleaching, which is less harmful from an environmental point of view and which is more appropriate for being utilized during the treatment of cellulose fibres.
  • the method initially defined which includes the characterizing method steps defined in claim 1.
  • the percentage of valuable oxidizing components in the residue liquid increases.
  • the oxygen may be supplied to the residue liquid under very simple conditions, for instance by injecting oxygen gas to the transport conduit usually existing in a pulp plant for conveying the residue liquid directly back to the pulp stream, i.e. no further oxidizing promoting means, such, as reactors working at high temperature and high pressure, are provided according to the invention.
  • the residue liquid treated in accordance with the inventive method may in comparison with known technique be taken care of in a more simple manner during the effluent cleaning and is more suitable for being utilized for the treatment of the cellulose fibres. Furthermore, since by the treatment according to the invention the quality of the residue liquid is enhanced a return of the residue liquid to the pulp stream results in an improved effect of the residue liquid.
  • the method according to the invention is characterized by a low complexity enabling application to pulp treatment plants of today.
  • At least a part of said part flow of the residue liquid may advantageously be conveyed back to the pulp stream before the pulp reaches at least one bleaching step.
  • the bleaching may be more efficient, which results in the fact that the brightness of the pulp may be increased or the quantity of hydrogen peroxide added may be reduced with the brightness maintained.
  • at least a part of said part flow of the residue liquid may be conveyed back to the pulp stream downstream of a bleaching step.
  • oxygen is supplied to the residue liquid at such a position that the dwell time of the oxygen in the residue liquid is at least three seconds before said part flow thereof reaches the pulp.
  • said dwell time may be greater than 10 seconds, for instance greater than 30 seconds.
  • oxygen is added to said part flow of the residue liquid by injecting oxygen gas into the pulp stream.
  • At least a second part flow of the residue liquid obtained is treated by oxygen and supplied to an effluent cleaning step via at least one direct connection, said preparing step, said bleaching step and/or said liquid removing step.
  • the oxidizing bleaching agent comprises at least one of hydrogen peroxide, ozone, hypochlorite, peracetic acid and chlorine dioxide.
  • the bleaching effect of such oxidizing bleaching agents may be improved if the residue liquid returned has been treated by oxygen.
  • the bleaching comprises at least one first bleaching step and a second bleaching step.
  • the present invention is applicable to different pulp preparing methods and the pulp may thus comprise at least one of chemimechanical pulp, semi-chemical pulp, mechanical pulp, chemical pulp and secondary fibre pulp.
  • Fig 1 discloses schematically a pulp stream for the treatment of cellulose fibres according to a first embodiment of the invention.
  • Fig 2 discloses schematically a pulp stream for the treatment of cellulose fibres according to a second embodiment of the invention.
  • the pulp of cellulose fibres is prepared in a first process step 1 schematically disclosed.
  • This preparing step 1 may for instance comprise digesting for preparing chemical pulp, repulping for preparing secondary fibre pulp and refining for preparing mechanical pulp. It is already now to be pointed out that the present invention is not limited to any particular type of pulp may be applicable to all known pulp types, for instance chemimechanical pulp, semi-chemical pulp, mechanical pulp, chemical pulp, such as sulphate and sulphite pulp, and secondary fibre pulp.
  • the preparing step 1 schematically disclosed may also comprise screening of the pulp for removing greater particles therefrom.
  • the pulp is transported along a pulp stream 2 to a first washing device 3, which may comprise one or several washing steps.
  • the washing device 3 disclosed also comprises a dewatering device, for instance in the form of a dewatering press.
  • the residue liquid obtained during the dewatering is transported to a residue liquid tank 4.
  • the pulp washed and dewatered is transported from the washing device 3 along the pulp stream 2 to a bleaching step 5 comprising a bleaching reactor.
  • bleaching chemicals are added by means of a mixing device 6 and steam is added at a steam injection device 7.
  • the bleaching chemicals which are utilized comprises oxidizing bleaching chemicals, such as hydrogen peroxide, ozone, hypochlorite, peracetic acid and chlorine dioxide.
  • alkali and silicate may also be added by means of the mixing device 6.
  • the pulp bleached is thereafter transported along the pulp stream 2 to a second washing device 8, which may comprise one or several washing steps.
  • the second washing device 8 comprises a dewatering device, for instance in the form of a dewatering press.
  • the residue liquid obtained during the dewatering is transported to a residue liquid tank 9.
  • the pulp is transported further along the pulp stream 2 to for instance further treatment, drying, storing or to an integrated paper mill.
  • the pulp in addition to the screening in the preparing step 1 also may be screened at several different locations along the pulp stream 2, for instance between the first washing device 3 and the bleaching step 5 and/or between the bleaching step 5 and the second washing device 8.
  • Liquid is supplied to the pulp stream 2 in an essentially counter flow manner against the flow direction of the pulp, i.e. relatively clean water is added in the end of the pulp stream 2 while used water, such as the residue liquid obtained, is added in the beginning of the pulp stream 2.
  • an essentially clean washing water or for instance residue water from an integrated paper mill, is added to the pulp stream 2 at 10, i.e. just before the pulp reaches the second washing device 8. Consequently, the residue liquid obtained is transported rearwardly and may be added to the process at one or several positions, for instance it may be added as a dilution to the second washing device 8 at 11 and/or the first washing device 3 at 12. It may also be added to the pulp stream 2 at 13 just before the pulp reaches the bleaching reactor 5, the pulp stream 2 at 14 after the bleaching reactor 5 and/or the preparing step 1 at 15.
  • a part of the residue liquid which is obtained in the residue liquid tank 4 and 9, respectively, is conveyed back to the process, for instance to the preparing step 1 via a transport conduit, schematically indicated as 4a and 9a, respectively, while another part of the residue liquid is supplied to an effluent treatment device 16 via the transport conduit 4a.
  • the transport conduits 4a, 9a may be realized as a number of pipes, the mere purpose of which are to convey the residue liquid.
  • Pump devices 4b and 9b are arranged on the transport conduits 4a and 9a, respectively, to provide the necessary transportation work.
  • the residue liquid is to be treated by oxygen.
  • This may be performed by adding oxygen to the residue liquid, for instance by an oxygen gas injection directly into the transport conduit 9a at 17 when it leaves the residue liquid tank 9.
  • all residue liquid leaving the residue liquid tank 9 will be treated by oxygen.
  • the oxygen injection at for instance 18 and/or 19 a more selective treatment of the residue liquid may be performed in accordance with the particular conditions which may prevail in a separate process.
  • the temperature of the residue liquid is, at the positions disclosed for the addition of oxygen, relatively low and may be between 50 and 90°C, preferably between 60 and 80°C.
  • the pH-value of the residue liquid at the positions disclosed for the addition of oxygen may be between 7 and 12, preferably between 8 and 10, with regard to basic bleaching agents and between 1 and 7 with regard to acid bleaching agents.
  • an approximate dwell time in residue liquid before it reaches the pulp is in the order of 0,5 to 4 minutes. It is to be noted that the dwell time may be influenced by pipe dimensions of the transport conduits 4a, 9a, and other plant specific designs.
  • Fig 2 discloses a second embodiment which differs from the first embodiment mainly in that it comprises a further bleaching step.
  • the pulp of cellulose fibres is thus prepared in a first preparing step 21 in a manner corresponding to the one of the first embodiment.
  • the pulp is transported along the pulp stream 22 to the first washing device 23, which may comprise one or several washing steps.
  • the residue liquid obtained at the dewatering in the washing device 23 is transported to the residue liquid tank 24.
  • the pulp washed and dewatered is transported further along the pulp stream 22 to the first bleaching step 25.
  • bleaching agents are supplied by means of a mixing device 26 and steam is supplied at the steam injecting device 27.
  • the pulp bleached is then transported along the pulp stream 22 to the second washing device 28, which may comprise one or several washing steps, and the residue liquid obtained at the dewatering is transported to the residue liquid tank 29. Thereafter, the pulp is transported further along the pulp stream 22 to the second bleaching step 30 which comprises a bleaching reactor.
  • bleaching chemicals are added by means of a second mixing device 31 and steam at a second steam injecting device 32.
  • the bleaching chemicals utilized according to the second embodiment also comprises oxidizing bleaching chemicals, such as hydrogen peroxide, ozone, hypochlorite, chlorine dioxide and peracetic acid. In the case of hydrogen peroxide alkali and silicate may also be added by means of the second mixing device 31. It is to be noted that different bleaching chemicals and/or different compositions of bleaching chemicals may be utilized in the two bleaching reactors 25 and 30.
  • the pulp bleached is then transported along the pulp stream 22 to the third washing device 33, which also may comprise one or several washing steps and a dewatering device, for instance in the form of a dewatering press.
  • the third washing device 33 may be replaced by a pure dewatering, for instance by means of a dewatering press.
  • the residue liquid obtain at the dewatering is transported to a third residue liquid tank 34.
  • the pulp is transported further along the pulp stream 22 to for instance further treatment, drying, storing or to an integrated paper mill.
  • the pulp concentration in the first bleaching step 25 may be between 8 and 20%, preferably about 15%, i.e.
  • the pulp may in addition to the screening in the preparing step 21 also be screened at several different locations along the pulp stream 22, for instance between the first washing device 23 and the first bleaching step 25, between the first bleaching step 25 and the second washing device 28 and/or between the second bleaching step 30 and the third washing device 33.
  • liquid is supplied to the pulp stream 22 in an essentially counter flow manner against the flow direction of the pulp, i.e. relatively clean water is supplied in the end of the pulp stream while used water, such as the residue liquid obtained, is supplied in the beginning of the pulp stream.
  • an essentially clean washing water for instance residue liquid from an integrated paper mill, may be supplied to the pulp stream 22 at 35, i.e. just before the pulp reaches the third washing device 33.
  • the residue liquid obtained in the third residue liquid tank 34 is thus transported rearwardly via the transport conduit 34a by means of the pump device 34b, and may be supplied to the process at one or several positions as exemplified below. It is to be noted that the residue liquid also may be returned to the pulp stream at other positions than those disclosed.
  • the residue liquid from the third residue liquid tank 34 may for instance be added as dilution to the third washing device 33 at 36, the second washing device 28 at 37 and/or a first washing device 23 at 38. Moreover, the residue liquid may be supplied to the pulp stream 22 at 39 just before the pulp reaches the secondary bleaching reactor 30 an/or at 40 just before the pulp reaches the first bleaching reactor 25. Likewise, it is also possible to supply residue liquid to the pulp stream 22 at 41 after the second bleaching reactor 5 and/or at 42 after the first bleaching reactor.
  • the residue liquid obtained in the second residue liquid tank 29 may for instance via the transport conduit 29a by means of the pump device 29b be returned to the process at 43 after the first bleaching reactor 25 or to the first residue liquid tank 24.
  • the residue liquid obtained in the first residue liquid tank 24 may for instance be returned to the process via the transport conduit 24a by means of the pump device 24b to the preparing step 21.
  • One part of the residue liquid obtained in the first residue liquid tank 24 and the second residue liquid tank 29 may in addition be removed from the process to a waste treatment device 44. It is also possible to convey at least a part of the residue liquid obtained in the third residue liquid tank 34 directly to the effluent treatment device 44.
  • Fig 2 discloses a number of examples of positions where oxygen may be added to the residue liquid in accordance with the present invention. Oxygen may for instance be added at 45 when the residue liquid leaves the third residue liquid tank 34. In such a manner all residue liquid leaving the third residue liquid tank 34 will be treated by oxygen.
  • the essentially clean washing water may also be added to the process at other positions than at the last washing device 8 and 33 disclosed, for instance at the associated residue liquid tank 9 and 34 respectively.
  • washing devices 3, 8, 23, 28 and 33 may be replaced by mere dewatering devices, for instance dewatering presses.
  • the transport conduits or pipes 4a, 9a, 24a, 29a, 34a may extend from the respective dewatering device directly to the pulp stream 2; 22 or to the effluent treatment device 16; 44.
  • the dwell time for the oxygen in the residue liquid may be increased by for instance adding oxygen to the residue liquid in any of the residue liquid tanks 9 and 34, respectively.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Polysaccharides And Polysaccharide Derivatives (AREA)
  • Coloring Foods And Improving Nutritive Qualities (AREA)

Claims (14)

  1. Procédé pour traiter des fibres de cellulose dans un courant de pâte (2; 22), comprenant les étapes consistant à:
    préparer (1; 21) une pâte;
    soumettre la pâte à un blanchiment,
    comprenant au moins une étape de blanchiment (5; 25, 30) par la fourniture d'un agent de blanchiment oxydant;
    extraire (8; 23, 33) le liquide de la pâte après le blanchiment, tout en récupérant un liquide résiduel;
    caractérisé par les étapes consistant à:
    renvoyer au moins un écoulement partiel du liquide résiduel récupéré directement dans le courant de pâte par l'intermédiaire d'une conduite de transport (4a, 9a; 24a, 29a, 34a) au moyen de dispositif de pompe (4b, 9b; 24b, 29b, 34b), et
    traiter ledit écoulement partiel du liquide résiduel avec de l'oxygène en ajoutant de l'oxygène audit écoulement partiel en aval du dispositif de pompe (4b, 9b; 24b, 29b, 34b) en injectant de l'oxygène gazeux (17-19; 45-51) dans ledit écoulement partiel;
    dans lequel l'oxygène est ajouté audit écoulement partiel du liquide résiduel
    avant que ledit écoulement partiel atteigne le courant de pâte en injectant l'oxygène gazeux (17-19; 45-51) dans ladite conduite de transport (4a, 9a; 24a, 29a, 34a), ou
    après que ledit écoulement partiel ait été introduit dans le courant de pâte en injectant l'oxygène gazeux dans le courant de pâte (2; 22).
  2. Procédé suivant la revendication 1, caractérisé en ce qu'au moins une partie dudit écoulement partiel du liquide résiduel est renvoyée dans le courant de pâte (2; 22) avant que la pâte atteigne au moins une étape de blanchiment (5; 25, 30).
  3. Procédé suivant l'une quelconque des revendications 1 et 2, caractérisé en ce qu'au moins une partie dudit écoulement partiel du liquide résiduel est renvoyée dans le courant de pâte en aval d'une étape de blanchiment (5; 25, 30).
  4. Procédé suivant l'une quelconque des revendications précédentes, caractérisé en ce que de l'oxygène est ajouté dans le liquide résiduel à une position (17; 45) telle que le temps de séjour de l'oxygène dans le liquide résiduel soit d'au moins trois secondes avant que ledit écoulement partiel de celui-ci atteigne le courant de pâte (2; 22).
  5. Procédé suivant la revendication 4, caractérisé en ce que ledit temps de séjour est supérieur à 10 secondes, par exemple supérieur à 30 secondes.
  6. Procédé suivant l'une quelconque des revendications précédentes, caractérisé en ce qu'au moins un deuxième écoulement partiel du liquide résiduel récupéré est traité à l'oxygène et est conduit, via une connexion directe, jusqu'à une étape de lavage d'effluent (16, 44), jusqu'à ladite étape de préparation (1), jusqu'à ladite étape de blanchiment (5, 25, 30) et/ou jusqu'à ladite étape d'extraction de liquide (3, 8, 23, 28, 33).
  7. Procédé suivant l'une quelconque des revendications précédentes, caractérisé en ce que l'agent de blanchiment oxydant comprend au moins une substance parmi le peroxyde d'hydrogène, l'ozone, l'hypochlorite, le dioxyde de chlore et l'acide peracétique.
  8. Procédé suivant l'une quelconque des revendications précédentes, caractérisé en ce que le blanchiment comprend au moins une première étape de blanchiment (25) et une deuxième étape de blanchiment (30).
  9. Procédé suivant la revendication 8, caractérisé en ce que le liquide résiduel est récupéré (33) à partir de la pâte après que cette dernière soit passée par la deuxième étape de blanchiment (30), et en ce qu'au moins un écoulement partiel (38) du liquide résiduel récupéré est conduit jusqu'au courant de pâte (22) avant que la pâte ait atteint la première étape de blanchiment (25).
  10. Procédé suivant l'une quelconque des revendications précédentes, caractérisé en ce que la pâte comprend de la pâte chimico-mécanique.
  11. Procédé suivant l'une quelconque des revendications précédentes, caractérisé en ce que la pâte comprend de la pâte semi-chimique.
  12. Procédé suivant l'une quelconque des revendications précédentes, caractérisé en ce que la pâte comprend de la pâte mécanique.
  13. Procédé suivant l'une quelconque des revendications précédentes, caractérisé en ce que la pâte comprend de la pâte chimique.
  14. Procédé suivant l'une quelconque des revendications précédentes, caractérisé en ce que la pâte comprend de la pâte de fibre secondaire.
EP97952166A 1996-12-27 1997-12-23 Traitement a l'oxygene de filtrats issus d'usines de blanchiment Expired - Lifetime EP0950136B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
SE9604802 1996-12-27
SE9604802A SE9604802L (sv) 1996-12-27 1996-12-27 Förfarande för behandling av cellulosafibrer
PCT/SE1997/002214 WO1998029598A1 (fr) 1996-12-27 1997-12-23 Traitement a l'oxygene de filtrats issus d'usines de blanchiment

Publications (2)

Publication Number Publication Date
EP0950136A1 EP0950136A1 (fr) 1999-10-20
EP0950136B1 true EP0950136B1 (fr) 2004-05-19

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Application Number Title Priority Date Filing Date
EP97952166A Expired - Lifetime EP0950136B1 (fr) 1996-12-27 1997-12-23 Traitement a l'oxygene de filtrats issus d'usines de blanchiment

Country Status (10)

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EP (1) EP0950136B1 (fr)
JP (1) JP2001519858A (fr)
AT (1) ATE267288T1 (fr)
AU (1) AU5582598A (fr)
BR (1) BR9714440A (fr)
CA (1) CA2275710C (fr)
DE (1) DE69729215T2 (fr)
NO (1) NO325725B1 (fr)
SE (1) SE9604802L (fr)
WO (1) WO1998029598A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008006946A1 (fr) * 2006-07-14 2008-01-17 Linde Aktiengesellschaft Procédé pour le traitement d'un filtrat avec de l'oxygène et utilisation de l'oxygène pour réduire les composants nuisibles dans un filtrat

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE522161C2 (sv) * 1999-06-17 2004-01-20 Kvaerner Pulping Tech Förfarande och anordning för syrgasdelignifiering med förbättrad kappareduktion
FI117391B (fi) 2000-05-16 2006-09-29 Andritz Oy Menetelmä ja laitteisto massan käsittelemiseksi
FI126551B (fi) 2009-11-25 2017-02-15 Andritz Oy Menetelmä nestevirtojen käsittelemiseksi sellutehtaalla
WO2015197917A1 (fr) * 2014-06-23 2015-12-30 Metsä Fibre Oy Procédé de délignification de suspensions fibreuses de cuisson alcaline

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0564443A1 (fr) * 1992-03-15 1993-10-06 Kamyr, Inc. Traitement d'éffluents de blanchiment
US5509999A (en) * 1993-03-24 1996-04-23 Kamyr, Inc. Treatment of bleach plant effluents

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008006946A1 (fr) * 2006-07-14 2008-01-17 Linde Aktiengesellschaft Procédé pour le traitement d'un filtrat avec de l'oxygène et utilisation de l'oxygène pour réduire les composants nuisibles dans un filtrat

Also Published As

Publication number Publication date
NO325725B1 (no) 2008-07-07
CA2275710C (fr) 2006-03-14
BR9714440A (pt) 2000-03-21
NO993120L (no) 1999-08-25
NO993120D0 (no) 1999-06-23
AU5582598A (en) 1998-07-31
DE69729215T2 (de) 2005-05-25
WO1998029598A1 (fr) 1998-07-09
JP2001519858A (ja) 2001-10-23
DE69729215D1 (de) 2004-06-24
EP0950136A1 (fr) 1999-10-20
ATE267288T1 (de) 2004-06-15
SE9604802L (sv) 1998-06-28
CA2275710A1 (fr) 1998-07-09
SE9604802D0 (sv) 1996-12-27

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