CA1255817A - Process for decreasing the nitrate content in water - Google Patents
Process for decreasing the nitrate content in waterInfo
- Publication number
- CA1255817A CA1255817A CA000470331A CA470331A CA1255817A CA 1255817 A CA1255817 A CA 1255817A CA 000470331 A CA000470331 A CA 000470331A CA 470331 A CA470331 A CA 470331A CA 1255817 A CA1255817 A CA 1255817A
- Authority
- CA
- Canada
- Prior art keywords
- water
- extraction
- wells
- pipes
- injection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/30—Aerobic and anaerobic processes
- C02F3/302—Nitrification and denitrification treatment
- C02F3/305—Nitrification and denitrification treatment characterised by the denitrification
- C02F3/306—Denitrification of water in soil
-
- 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
- C02F1/58—Treatment of water, waste water, or sewage by removing specified dissolved compounds
- C02F1/62—Heavy metal compounds
- C02F1/64—Heavy metal compounds of iron or manganese
-
- 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
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S210/00—Liquid purification or separation
- Y10S210/902—Materials removed
- Y10S210/903—Nitrogenous
Abstract
Abstract The invention relates to a process for decreasing the content of nitrate in ground water, artificial ground water, that is infiltrated surface water, or surface water flowing through an aquifer or through a basin or a filter containing naturally occurring filter material. Water containing denitrification organisms and/or substrate there-fore is introduced intermittently through a number of injection wells or injection pipes arranged around one or more extraction wells or extraction pipes for purified water. During each introduction of water containing de-nitrification organisms and/or substrate therefore said water is fed to only some of said injection wells or pipes and simultaneously water is drawn from nearby, adjacent or intervening injection wells or pipes for the purpose of creating a denitrification zone at a distance sufficient-ly far from the extraction well or extraction pipe.
Description
~P~ 17 A process for decreasing the nitrate content in water .
The presen-t invention relates to a process for decreasing the content of nitrate in ground water, artificial ground water, that is infiltrated surface water, or surface water.
~ n cer-tain areas, especialLy intensively cultivated areas, ground wa-ter and surEace water may conta:in nitrate contents so high tha-t it will be necessary to reduce said contents to levels below the existing limit value for nitrate in drinking water.
SE~A-7502197-2 describes a process for rernoving noxious nitrogen compounds, e.g. nitrates, from water, especially ground water. In said processwater containing denitrification microorganisms is introduced continuously or intermittently into an aquifer around a ground water well. The present invention is an improvement of said known process wherein a clearly defined denitrification zone is formed at a desired distance from an extraction well, thereby permitting an optimal nitrate reduction in the water to be purified.
Thus, the present invention relates to a process for decreasing the content of nitrate in ground water, artificial ground water, that is infiltrated surface water, or surface water flowing through an aquifer or through a basin or a filter containing naturally occur-ring filter material, in which process water containing denitrification organisms and/or substrate therefore is introduced intermittently through a number of injection wells or in~ection pipes arranged around one or more extraction wells or extraction pipes for purified water.
This process is characterized in that, during each introduction of water containing denitrification organisms ,j,~P, ' ~ ' s~ t7 and/or substrate therefore, said wa-ter is fed to only some of the inject.ion wells or injection pipes, and that simultaneously water is rlrawn from nearby, adjacent ox intervening injection we].ls or injection pipes for the purpose of crea-ting a denitrification zone a-t a distance sufficiently far from the extract:ion well or extraction pipe.
The water Eed to some of the injection wells may consist of a portion of the wa-ter drawn from -the ex-traction well and/or water drawn from other, nearby injec-tion wells.
If water containing denitrifica-ti.on organisms and/or substrate therefore is introduced in-to injection wells and simultaneously water is pumped from -the extraction well but no water is pumped from one or more of the injection wells, the water added will flow in narrow zones from the respective injection wells directly towards the extraction well. This means that -the injection w.ater will not cover the whole area be-tween the injection wells, and impure water will flow between said narrow zones directly towards the extraction well.
In such a case the purification process will not work satisfactorily, resulting in a deteriorated water quality.
On the other hand, if in accordance with the invention water is introduced into some injection wells and simultan-eou-sly water is drawn from adjacent or intervening injection wells the water thus introduced will flow in the aquifer in a manner such t~at the areas between the injection wells are covered completely, with a con-comitant formation of a clearly defined denitrification zone at a distance sufficiently far from the extraction well. All water drawn from the extraction well will thus pass through said zone, whereby the best possible nitrate reduction is attained.
~ ~'3~ ~ ~ 7 The preEerred embodiment of -the invention, viz.
decreasing the nitrate content in si-tu in an aquifer, will be described in greater detail below.
Nitrate lons may be eliminated from ground water by activating denitrificati.on organisms normally existing in the aquifer. If necessary, deni-triEication organisms have to be added at an early stage. The microorganisms utilized require a supply of organic carbon -to bring about a denitrification. Examples of useful subs-trates are sucrose, methanol, ethanol, an ace-tate or molasses.
The subs-trate is dissolved in or mixed with the water introduced -through -the injection wells.
If a sufficiently large strain of denitrification organisms is available all the organic carbon injected will be utilized for denitrification. A certain amoun-t of substrate will then result in the reduction of a given amount of nitrate to nitrogen gas.
Field tests have shown that it is possible to act.ivate microbial processes in the ground by means of substrate injections. This results in a lowering of the nitrate content by denitrification. Thus, the nitrate content in ground water has been decreased from about 50 mg/l to values below 10 mg/l.
The creation of reducing conditions also results in other effects, viz. that the content of dissolved manganese in the water increases and that residual nitrite may be present. Said changes are not desirable from a water hygienic point of view but they are completely reversible if the water is degassed and oxygenated. Consequently, from a biological point of view it is quite clear that reduction and subsequent oxidation may bring about a practically complete elimination of nitrate without changing the water quality in other respects.
L'7 Two essentially different technical solu-tions are conceivable for applyiny the method in practice.
(1) Two zones, one reduced and one oxidized, are created around one and the same well. When drawing water - from the well the water will be filtered -through said zones and thus be purified.
The presen-t invention relates to a process for decreasing the content of nitrate in ground water, artificial ground water, that is infiltrated surface water, or surface water.
~ n cer-tain areas, especialLy intensively cultivated areas, ground wa-ter and surEace water may conta:in nitrate contents so high tha-t it will be necessary to reduce said contents to levels below the existing limit value for nitrate in drinking water.
SE~A-7502197-2 describes a process for rernoving noxious nitrogen compounds, e.g. nitrates, from water, especially ground water. In said processwater containing denitrification microorganisms is introduced continuously or intermittently into an aquifer around a ground water well. The present invention is an improvement of said known process wherein a clearly defined denitrification zone is formed at a desired distance from an extraction well, thereby permitting an optimal nitrate reduction in the water to be purified.
Thus, the present invention relates to a process for decreasing the content of nitrate in ground water, artificial ground water, that is infiltrated surface water, or surface water flowing through an aquifer or through a basin or a filter containing naturally occur-ring filter material, in which process water containing denitrification organisms and/or substrate therefore is introduced intermittently through a number of injection wells or in~ection pipes arranged around one or more extraction wells or extraction pipes for purified water.
This process is characterized in that, during each introduction of water containing denitrification organisms ,j,~P, ' ~ ' s~ t7 and/or substrate therefore, said wa-ter is fed to only some of the inject.ion wells or injection pipes, and that simultaneously water is rlrawn from nearby, adjacent ox intervening injection we].ls or injection pipes for the purpose of crea-ting a denitrification zone a-t a distance sufficiently far from the extract:ion well or extraction pipe.
The water Eed to some of the injection wells may consist of a portion of the wa-ter drawn from -the ex-traction well and/or water drawn from other, nearby injec-tion wells.
If water containing denitrifica-ti.on organisms and/or substrate therefore is introduced in-to injection wells and simultaneously water is pumped from -the extraction well but no water is pumped from one or more of the injection wells, the water added will flow in narrow zones from the respective injection wells directly towards the extraction well. This means that -the injection w.ater will not cover the whole area be-tween the injection wells, and impure water will flow between said narrow zones directly towards the extraction well.
In such a case the purification process will not work satisfactorily, resulting in a deteriorated water quality.
On the other hand, if in accordance with the invention water is introduced into some injection wells and simultan-eou-sly water is drawn from adjacent or intervening injection wells the water thus introduced will flow in the aquifer in a manner such t~at the areas between the injection wells are covered completely, with a con-comitant formation of a clearly defined denitrification zone at a distance sufficiently far from the extraction well. All water drawn from the extraction well will thus pass through said zone, whereby the best possible nitrate reduction is attained.
~ ~'3~ ~ ~ 7 The preEerred embodiment of -the invention, viz.
decreasing the nitrate content in si-tu in an aquifer, will be described in greater detail below.
Nitrate lons may be eliminated from ground water by activating denitrificati.on organisms normally existing in the aquifer. If necessary, deni-triEication organisms have to be added at an early stage. The microorganisms utilized require a supply of organic carbon -to bring about a denitrification. Examples of useful subs-trates are sucrose, methanol, ethanol, an ace-tate or molasses.
The subs-trate is dissolved in or mixed with the water introduced -through -the injection wells.
If a sufficiently large strain of denitrification organisms is available all the organic carbon injected will be utilized for denitrification. A certain amoun-t of substrate will then result in the reduction of a given amount of nitrate to nitrogen gas.
Field tests have shown that it is possible to act.ivate microbial processes in the ground by means of substrate injections. This results in a lowering of the nitrate content by denitrification. Thus, the nitrate content in ground water has been decreased from about 50 mg/l to values below 10 mg/l.
The creation of reducing conditions also results in other effects, viz. that the content of dissolved manganese in the water increases and that residual nitrite may be present. Said changes are not desirable from a water hygienic point of view but they are completely reversible if the water is degassed and oxygenated. Consequently, from a biological point of view it is quite clear that reduction and subsequent oxidation may bring about a practically complete elimination of nitrate without changing the water quality in other respects.
L'7 Two essentially different technical solu-tions are conceivable for applyiny the method in practice.
(1) Two zones, one reduced and one oxidized, are created around one and the same well. When drawing water - from the well the water will be filtered -through said zones and thus be purified.
(2) Reducing and oxidizin~ environments respectively are created around different wells.
Said -two solutions are illustrated in the drawiny figures 1 and 2.
(1) Two zones around one well.
Fig. 1 shows four wells in a system for microbiologic nitrate reduction. Around all the wells there is a gallery of injection wells arranged as two circles at different distances from the central extraction well. In the outer circle of injection wells water is circulated by pumping and simultaneously substrate is added (well 2).
A more or less annular zone enriched with organic substance is formed in this way. The substrate is utilized by de-nitrification organisms which reduce nitrate to nitrogen.
A secondary effect of the reducing environment in the aquifer is that the nitri-te content may be slightly in-creased and that manganese may be dissolved in a first phase. An oxidized zone nearer the extraction well has therefore been formed earlier by means of nitrate free water oxygenated in an oxygenator (well 1). After a certain contact time a volume of purified water correspond-ing to the treatment made may be supplied (well 3). During the extraction of this water volume, nitrate free but not oxygenated water has flown into the zone adjacent to the extraction well (well 4) and this water may, via an oxygenator, be pumped ove~ tothe inactive well 1. All wells are used in sequence in this manner, sometimes as supply well and sometimes Eor other functions.
-: ' . ' , . - ' ' , ~. . . .
(2) Zones crea-ted around separate wells.
Water pu~ped from a raw water well (see Fig. 2) is -treated with substra-te and then :infiltrated in injection wells around special treatment wells. The infiltration is carried ou-t in accordance with the invention. Reducing zones are thus formed in the aquifer around said wells, and in said zones nitrate is reduced microbiologically to nitrogen. After a certain contact time -the water, which is now free from nitrate but may con-tain residual nitri-te, is pumped over to another well sys-tem. The water is degassed and oxygenated in an oxygenator station before -the infiltration in said second well system. In the oxidizing aquifer the residual nitri-te, if any, is oxidized back to nitrate. Water drawn from a reduction well will contain a certain amount of manganese. After oxygenation of the water this manganese has to be separated, e.g. in a rapid filter, so that no clogging will occur when introducing the water into injection wells around an oxidation well.
The process according to the invention may also be used for the purification of ground water or surface water in e.g. a basin or a filter containing naturally occurring filter material. For ins-tance, soil may be excavated to form a cavity, and a sealing layer of clay, concrete, plastics tarpaulin or the like may be applied along the mantle surface. Infiltration pipes or drain pipes for raw water are applied inside the man-tle of the basin thus prepared, whereupon the basin is filled with filter material, e.g. sand. Purified water is drawn from an extraction pipe or extraction well in the centre, and injection pipes are arranged between the mantle and the centre. A filter container of steel or plastics or other material may be employed instead of such a basin.
Raw water is introduced inside the mantle of such a 5~:~7 filter con-tainer, and purifled water is drawn from an extraction pipe in the centre. Injection pipes are arranged between the mantle and the cen-tre. In -the devices described above there will be a radial flow of raw water from the periphery towards the centre of a basin or filtex container, but i-t is also possible to arrange for flow paths in the opposite direction, that is, from the centre to the mantle. Alterna-tively the raw water flow may be axial. Thus, raw water may be fed -to one end of the filter container and purified wa-ter withdrawn from`the other end. In this case injection pipes are disposed in suitable positions between the inlet end and the outle-t end.
' ~, ,
Said -two solutions are illustrated in the drawiny figures 1 and 2.
(1) Two zones around one well.
Fig. 1 shows four wells in a system for microbiologic nitrate reduction. Around all the wells there is a gallery of injection wells arranged as two circles at different distances from the central extraction well. In the outer circle of injection wells water is circulated by pumping and simultaneously substrate is added (well 2).
A more or less annular zone enriched with organic substance is formed in this way. The substrate is utilized by de-nitrification organisms which reduce nitrate to nitrogen.
A secondary effect of the reducing environment in the aquifer is that the nitri-te content may be slightly in-creased and that manganese may be dissolved in a first phase. An oxidized zone nearer the extraction well has therefore been formed earlier by means of nitrate free water oxygenated in an oxygenator (well 1). After a certain contact time a volume of purified water correspond-ing to the treatment made may be supplied (well 3). During the extraction of this water volume, nitrate free but not oxygenated water has flown into the zone adjacent to the extraction well (well 4) and this water may, via an oxygenator, be pumped ove~ tothe inactive well 1. All wells are used in sequence in this manner, sometimes as supply well and sometimes Eor other functions.
-: ' . ' , . - ' ' , ~. . . .
(2) Zones crea-ted around separate wells.
Water pu~ped from a raw water well (see Fig. 2) is -treated with substra-te and then :infiltrated in injection wells around special treatment wells. The infiltration is carried ou-t in accordance with the invention. Reducing zones are thus formed in the aquifer around said wells, and in said zones nitrate is reduced microbiologically to nitrogen. After a certain contact time -the water, which is now free from nitrate but may con-tain residual nitri-te, is pumped over to another well sys-tem. The water is degassed and oxygenated in an oxygenator station before -the infiltration in said second well system. In the oxidizing aquifer the residual nitri-te, if any, is oxidized back to nitrate. Water drawn from a reduction well will contain a certain amount of manganese. After oxygenation of the water this manganese has to be separated, e.g. in a rapid filter, so that no clogging will occur when introducing the water into injection wells around an oxidation well.
The process according to the invention may also be used for the purification of ground water or surface water in e.g. a basin or a filter containing naturally occurring filter material. For ins-tance, soil may be excavated to form a cavity, and a sealing layer of clay, concrete, plastics tarpaulin or the like may be applied along the mantle surface. Infiltration pipes or drain pipes for raw water are applied inside the man-tle of the basin thus prepared, whereupon the basin is filled with filter material, e.g. sand. Purified water is drawn from an extraction pipe or extraction well in the centre, and injection pipes are arranged between the mantle and the centre. A filter container of steel or plastics or other material may be employed instead of such a basin.
Raw water is introduced inside the mantle of such a 5~:~7 filter con-tainer, and purifled water is drawn from an extraction pipe in the centre. Injection pipes are arranged between the mantle and the cen-tre. In -the devices described above there will be a radial flow of raw water from the periphery towards the centre of a basin or filtex container, but i-t is also possible to arrange for flow paths in the opposite direction, that is, from the centre to the mantle. Alterna-tively the raw water flow may be axial. Thus, raw water may be fed -to one end of the filter container and purified wa-ter withdrawn from`the other end. In this case injection pipes are disposed in suitable positions between the inlet end and the outle-t end.
' ~, ,
Claims (2)
1. A process for decreasing the content of nitrate in ground water, artificial ground water, that is infiltrated surface water, or surface water flowing through an aquifer or through a basin or a filter containing natural-ly occurring filter material, in which process water containing denitrification organisms and/or substrate therefore is introduced intermittently through a number of injection wells or injection pipes arranged around one or more extraction wells or extraction pipes for purified water, characterized in that, during each introduction of water containing denitrification organisms and/or substrate therefore, said water is fed to only some of the injection wells or injection pipes, and that simultaneously water is drawn from nearby, adjacent or intervening injection wells or injection pipes for the purpose of creating a denitrification zone at a distance sufficiently far from the extraction well or extraction pipe.
2. A process according to claim 1, characterized in that, in order to oxidize manganese and residual nitrite, if any, in the water, an oxidation zone is created between the denitrification zone and the extraction well or extraction pipe by an intermittent introduction of water containing oxygen or oxygen-releasing substances.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE8400190-8 | 1984-01-16 | ||
| SE8400190A SE439917B (en) | 1984-01-16 | 1984-01-16 | PROCEDURE TO REDUCE NITRATE CONTENT IN GROUND WATER |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1255817A true CA1255817A (en) | 1989-06-13 |
Family
ID=20354316
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000470331A Expired CA1255817A (en) | 1984-01-16 | 1984-12-17 | Process for decreasing the nitrate content in water |
Country Status (13)
| Country | Link |
|---|---|
| US (1) | US4683064A (en) |
| EP (1) | EP0154105B1 (en) |
| JP (1) | JPS61500895A (en) |
| AT (1) | ATE28619T1 (en) |
| AU (1) | AU572605B2 (en) |
| CA (1) | CA1255817A (en) |
| DE (1) | DE3465068D1 (en) |
| ES (1) | ES8602548A1 (en) |
| FI (1) | FI78667C (en) |
| HU (1) | HU197551B (en) |
| SE (1) | SE439917B (en) |
| WO (1) | WO1985003067A1 (en) |
| YU (1) | YU45224B (en) |
Families Citing this family (25)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DK161157C (en) * | 1985-03-05 | 1991-12-09 | Joergen Krogh Andersen | PROCEDURE FOR PREPARING DRINKING WATER |
| SE8603843A0 (en) * | 1986-09-12 | 1988-03-13 | Vyrmetoder Ab | Process for purification of wastewater containing nitrate and / or nitrite |
| US4749491A (en) * | 1987-04-02 | 1988-06-07 | E. I. Du Pont De Nemours And Company | Microbiological decomposition of chlorinated aliphatic hydrocarbons |
| FR2622567B1 (en) * | 1987-11-04 | 1991-01-18 | Gestion Sa Fse Et | METHOD FOR IN SITU ANOXIC DETOXIFICATION OF CONTAMINATED SUBTERRANEAN TABLECLOTHS |
| US5006250A (en) * | 1987-12-04 | 1991-04-09 | The Board Of Trustees Of The Leland Stanford Junior University | Pulsing of electron donor and electron acceptor for enhanced biotransformation of chemicals |
| US5080782A (en) * | 1989-06-08 | 1992-01-14 | Environmental Science & Engineering, Inc. | Apparatus for bioremediation of sites contaminated with hazardous substances |
| US5185080A (en) * | 1990-06-04 | 1993-02-09 | Gregory Boyle | Process for the on-site removal of nitrates from wastewater |
| SE466851B (en) * | 1990-07-04 | 1992-04-13 | Paref Ab | PROCEDURE AND DEVICE FOR PURIFICATION OF WATER IN GROUNDWATER CONDUCTING STORES |
| US5206168A (en) * | 1991-02-28 | 1993-04-27 | Gregory Boyle | Method for small system wastewater denitrification |
| US5514279A (en) * | 1991-03-04 | 1996-05-07 | University Of Waterloo | System for treating contaminated groundwater |
| GB9104509D0 (en) * | 1991-03-04 | 1991-04-17 | Blowes David W | System for treating contaminated ground water |
| JP2608493B2 (en) * | 1991-07-19 | 1997-05-07 | 株式会社荏原総合研究所 | Method and apparatus for cleaning soil and groundwater contaminated with organochlorine compounds |
| WO1994005604A1 (en) * | 1992-08-27 | 1994-03-17 | United States Department Of Energy | Bioremediation of contaminated groundwater |
| US5405531A (en) * | 1993-02-16 | 1995-04-11 | Geo-Microbial Technologies, Inc. | Method for reducing the amount of and preventing the formation of hydrogen sulfide in an aqueous system |
| US6143177A (en) * | 1995-04-11 | 2000-11-07 | Arcadis Geraghty & Miller, Inc. | Engineered in situ anaerobic reactive zones |
| US5554290A (en) * | 1995-04-11 | 1996-09-10 | Geraghty & Miller, Inc. | Insitu anaerobic reactive zone for insitu metals precipitation and to achieve microbial de-nitrification |
| US5730550A (en) * | 1995-08-15 | 1998-03-24 | Board Of Trustees Operating Michigan State University | Method for placement of a permeable remediation zone in situ |
| US5910245A (en) * | 1997-01-06 | 1999-06-08 | Ieg Technologies Corp. | Bioremediation well and method for bioremediation treatment of contaminated water |
| US6342159B1 (en) | 1997-01-29 | 2002-01-29 | Ensolve Biosystems, Inc. | Shipboard biomechanical oil water separator |
| US6551815B1 (en) | 1997-05-09 | 2003-04-22 | University Of New Mexico | In situ denitrification |
| US6007274A (en) | 1997-05-19 | 1999-12-28 | Arcadis Geraghty & Miller | In-well air stripping, oxidation, and adsorption |
| US6116816A (en) | 1998-08-26 | 2000-09-12 | Arcadis Geraghty & Miller, Inc. | In situ reactive gate for groundwater remediation |
| US7407583B2 (en) * | 2004-06-16 | 2008-08-05 | University Technologies International, Llp | In-situ groundwater nitrification and de-nitrification remediation system |
| MX2007001487A (en) * | 2004-08-06 | 2007-06-11 | Tyreso Miljokemi | Method and apparatus for the purification of ground water. |
| EA024300B1 (en) | 2009-06-02 | 2016-09-30 | Юнайтед Уотер Интернешнл Аг | Ground water purification plant based on biological oxidation and reduction processes |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI43852B (en) * | 1969-02-13 | 1971-03-01 | Yrjoe Reijonen | |
| DE2607114A1 (en) * | 1975-02-27 | 1976-09-09 | Euroc Administration Ab | PROCEDURE FOR REMOVING NITROGEN COMPOUNDS IN WATER |
| DE2542333C2 (en) * | 1975-09-23 | 1982-05-06 | Ulrich Dr.-Ing. 3012 Langenhagen Rott | Process for purifying groundwater from manganese and iron |
| CH653317A5 (en) * | 1982-02-18 | 1985-12-31 | Sulzer Ag | METHOD AND SYSTEM FOR THE BIOLOGICAL DENITRIFICATION OF GROUNDWATER. |
| SE434388B (en) * | 1982-11-10 | 1984-07-23 | Vyrmetoder Ab | PROCEDURE FOR REDUCING IRON AND MANGANE CONTENTS IN GROUND WATER |
| FR2550182B1 (en) * | 1983-08-02 | 1988-02-26 | Rech Geolog Miniere | METHOD OF DENITRIFICATION OF GROUNDWATER FOR POTABILIZATION |
| FR2798894B1 (en) * | 1999-09-24 | 2002-05-03 | Eurostyle Sa | THERMOPLASTIC PIECE FOR MASKING AN INFLATABLE SAFETY CUSHION |
-
1984
- 1984-01-16 SE SE8400190A patent/SE439917B/en not_active IP Right Cessation
- 1984-12-17 HU HU85808A patent/HU197551B/en not_active IP Right Cessation
- 1984-12-17 AU AU38305/85A patent/AU572605B2/en not_active Ceased
- 1984-12-17 US US06/756,972 patent/US4683064A/en not_active Expired - Lifetime
- 1984-12-17 WO PCT/SE1984/000432 patent/WO1985003067A1/en active IP Right Grant
- 1984-12-17 JP JP60500161A patent/JPS61500895A/en active Granted
- 1984-12-17 EP EP84850393A patent/EP0154105B1/en not_active Expired
- 1984-12-17 DE DE8484850393T patent/DE3465068D1/en not_active Expired
- 1984-12-17 AT AT84850393T patent/ATE28619T1/en not_active IP Right Cessation
- 1984-12-17 CA CA000470331A patent/CA1255817A/en not_active Expired
- 1984-12-18 YU YU2142/84A patent/YU45224B/en unknown
-
1985
- 1985-01-15 ES ES539581A patent/ES8602548A1/en not_active Expired
- 1985-09-13 FI FI853512A patent/FI78667C/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| YU214284A (en) | 1988-04-30 |
| FI78667C (en) | 1989-09-11 |
| US4683064A (en) | 1987-07-28 |
| JPS61500895A (en) | 1986-05-08 |
| SE439917B (en) | 1985-07-08 |
| EP0154105B1 (en) | 1987-07-29 |
| AU3830585A (en) | 1985-07-30 |
| ATE28619T1 (en) | 1987-08-15 |
| YU45224B (en) | 1992-05-28 |
| FI853512L (en) | 1985-09-13 |
| HU197551B (en) | 1989-04-28 |
| JPH0535037B2 (en) | 1993-05-25 |
| DE3465068D1 (en) | 1987-09-03 |
| FI78667B (en) | 1989-05-31 |
| EP0154105A1 (en) | 1985-09-11 |
| WO1985003067A1 (en) | 1985-07-18 |
| SE8400190D0 (en) | 1984-01-16 |
| ES539581A0 (en) | 1985-12-01 |
| AU572605B2 (en) | 1988-05-12 |
| ES8602548A1 (en) | 1985-12-01 |
| FI853512A0 (en) | 1985-09-13 |
| HUT37376A (en) | 1985-12-28 |
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