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WO1997003928A1 - Process for treating a surplus activated sludge - Google Patents

Process for treating a surplus activated sludge Download PDF

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Publication number
WO1997003928A1
WO1997003928A1 PCT/RU1996/000032 RU9600032W WO9703928A1 WO 1997003928 A1 WO1997003928 A1 WO 1997003928A1 RU 9600032 W RU9600032 W RU 9600032W WO 9703928 A1 WO9703928 A1 WO 9703928A1
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WO
WIPO (PCT)
Prior art keywords
activated sludge
surplus activated
treating
sulfate
pulp production
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.)
Ceased
Application number
PCT/RU1996/000032
Other languages
French (fr)
Inventor
Vladimir Pavlovich Grudinin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ANISIMOV ALEXANDR PAVLOVICH
Original Assignee
ANISIMOV ALEXANDR PAVLOVICH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by ANISIMOV ALEXANDR PAVLOVICH filed Critical ANISIMOV ALEXANDR PAVLOVICH
Priority to AU46802/96A priority Critical patent/AU4680296A/en
Priority to BR9609736-1A priority patent/BR9609736A/en
Priority to JP9506587A priority patent/JPH11510090A/en
Priority to FI980091A priority patent/FI980091A0/en
Priority to EP96902522A priority patent/EP0842125A1/en
Publication of WO1997003928A1 publication Critical patent/WO1997003928A1/en
Priority to NO980210A priority patent/NO980210D0/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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
    • D21C11/0064—Aspects concerning the production and the treatment of green and white liquors, e.g. causticizing green liquor
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/14—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/14—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents
    • C02F11/143—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents using inorganic substances
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/14—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents
    • C02F11/143—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents using inorganic substances
    • C02F11/145—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents using inorganic substances using calcium compounds

Definitions

  • the present invention relates to a process for treating settlings formed during the biological purification of municipal and industrial waste water and may be used in various fields of industry, in particular in paper and pulp production.
  • the main disadvantage of the known process consists an low effectiveness and high duration of a process for dehydrating the settlings by filtering, which is caused by an unfavorable structure of said settlings that firmly retain water and have a high specific filtration resist-ance.
  • the known process requires the use of expensive alkaline reagents /see Y ⁇ . N. Nelepin, "Sulfate Pulp Production”, “Lesnaya Promyshlennost", Moscow, 1990, p. 531/.
  • the present invention is made in order to solve the above problems included in the prior arts, and an object of this invention is to provide a new process for treating a surplus activated sludge enabling intensification of the process for dehydrating the settlings by filtering, avoiding the use of expensive chemical reagents, a complete utilization of the process products so obtained (a clarified alkaline hydrolyzate and an ash residue) as well as utilization of the sulfate-pulp production waste with minimal costs.
  • the above technical result is achieved in accordance with the present invention by treating a pre-thickened surplus activated sludge with white slime obtained at the stage of causticizing green liquor in the process of the sulfate-pulp production, with stirring and in a volume ratio of white slime : surplus activated sludge equal to 1 : 5 - 10 followed by dehydration by means of filtering, drying and burning down of the dehydrated settlings.
  • the present process differs from the known one in that it provides for the treatment of the pre-dehydrated surplus activated sludge with white slime obtained at the stage of causticizing green liquor in the process of the sulfate-pulp production, with stirring and in a volume ratio of white slime : surplus activated sludge equal to 1 : 5 - 10.
  • White slime used in the present process for treating the surplus activated sludge is a sulfate-pulp production waste being a black suspension with a density of 1.25 - 1.35 Kg/cub. dm and having the following chemical composition, % wt.:
  • Using white slime in accordance with the present process allows solution of two problems at once: on the one hand, to intensify and lower the price of the process for treating the surplus activated sludge and, on the other hand, to significantly simplify and lower the price of the process for utilizing white slime.
  • a process for treating the surplus activated sludge thickened when p-resettling the precipitate, by means of white slime containing alkali residues is accompanied with practically a complete alkaline hydrolysis of the bioorganic part of the sludge (constituting not less than 83 % wt. on dry residue) with the formation of salts of amino acids, amino alcohols and a number of protein derivatives.
  • calcium carbonate constituting the major contents of white slime is uniformly distributed, when stirred thoroughly, among undissolved large fibres and solid particles present in the surplus activated sludge in the amount up to 17 % wt. on dry basis.
  • the present process is carried out. m the following manner.
  • the surplus activated sludge is subjected to pre-thickening in a radial or vertical pond. Most preferably, thickening is carried out up to the surplus activated sludge concentration of 18 - 40 g/1.
  • the surplus activated sludge is fed to a mixer where it is treated with white slime, while stirring.
  • White slime is used in a volume ratio to the surplus activated sludge equal to 1 : 5 - 10 which allows achievement of a maximal efficiency of post-filtering.
  • a filtering rate reduces significantly. It is not to the purpose of technology to use white slime in the amounts exceeding the claimed ratio.
  • stirring is carried out at a temperature of between 75 and 104 C. It is also possible to use lower temperatures, up to room temperature, but in this case a process for treating becomes more prolonged.
  • the treatment is carried out to a complete dissolution of a bioorganic part of the surplus activated sludge. Then, a mixture so obtained which contains an alkaline hydrolyzate, undissolved fibres and solid particles present in the surplus activated sludge, as well as calcium carbonate uniformly distributed among the particles of sludge settlings as a result of stirring, are fed to a vacuum filter or a pressure filter and subjected to dehydration.
  • a clarified alkaline hydrolyzate obtained upon filtration may be used, without a subsequent treatment, in the manufacturing cycle of the sulfate-pulp production at the stage of reagent regeneration.
  • a dehydrated precipitate formed on a filter surface is readily removed from the filter surface, thereupon it is subjected to heat drying in drier drums and fed to burn down in an utilization plant furnace.
  • An ash residue comprising calcium oxide is used in the manufacturing cycle of the sulfate-pulp production at the stage of a green liquor causticizing.
  • a concentration of 80 g/l, 0.75 1 of a white slime suspension is added and thoroughly stirred for 15 minutes at 95 C.
  • a mixture so obtained is fed to a vacuum filter and subjected to dehydration of the settlings.
  • a filtration rate is determined to be 40 I/sq. m/min.
  • a clarified alkaline hydrolyzate is fed to be used in the manufacturing cycle of the sulfate-pulp production.
  • a dehydrated precipitate formed on a filter surface is removed and subjected to heat drying at 850 C, thereupon it is burned down.
  • An ash residue obtained is fed to the stage of a green liquor causticizing.
  • the present process for treating the surplus activated sludge allows intensification of the filtration process, avoiding the use of expensive chemical reagents (at. the expense of using waste of the sulfate-pulp production), a complete utilization of products obtained when treating the sludge (an ash residue and a clarified alkaline hydrolyzate) as well as utilization of the sulfate-pulp production waste, that is white slime, with simplification of the production procedures and techniques and significant reduction of material costs.
  • a filtration rate in accordance with the known process is 4 l/sq. m/min. Besides, reduction in a dehydration process time according to the present process results in the decrease of energy consumed to realize thereof.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mechanical Engineering (AREA)
  • Paper (AREA)
  • Treatment Of Sludge (AREA)
  • Separation Of Suspended Particles By Flocculating Agents (AREA)

Abstract

The present invention relates to a process for treating settlings formed during the biological purification of municipal and industrial waste water and may be used in various fields of industry, in particular in paper and pulp production. A pre-thickened surplus activated sludge is subjected to treatment with white slime obtained at the state of causticizing green liquour in the sulfate-pulp production, while stirring. White slime is used in a volume ratio to the surplus activated sludge equal to 1 : 5 - 10. Thereupon, the sludge so treated is subjected to dehydration by filtering, preferably at a temperature of between 75 and 104 °C. The dehydrated settlings are dried and burned down. An ash residue so obtained as well as a clarified alkaline hydrolyzate are used in the manufacturing process of the sulfate-pulp production. The present process for treating the surplus activated sludge allows intensification of the filtration process, avoiding the use of expensive chemical reagents, a complete utilization of products obtained when treating the sludge as well as utilization of the sulfate-pulp production waste, that is white slime, with simplification of the production procedures and techniques and significant reduction of material costs.

Description

PROCESS FOR TREATING A SURPLUS ACTIVATED SLUDGE
TECHNICAL FIELD
The present invention relates to a process for treating settlings formed during the biological purification of municipal and industrial waste water and may be used in various fields of industry, in particular in paper and pulp production.
BACKGROUND ART
There have been known processes for treating a surplus activated sludge with special reagents followed by its separation into water and thickened settlings by means of filtering or settling. In most cases, an aqueous solution of ferric chloride and lime milk /see O. I. Yakovleva et al., "Sewage Treatment", "Lesnaya Promyshlennost", Moscow, 1975, pp. 40 - 43/, as well as various ammonium salts /see US Patent No. 4240904, Int. Cl. CO2F 11/14, 1980/ and organic compounds /see USSR Inventor's Certificate No. 827424, Int. CI. CO2F 11/14, 1981/ are used for this purpose.
There have been also known processes for treating a surplus activated sludge by separating into water and thickened settlings by means of filtering and using auxiliary filtering substances such as, for example inorganic compounds, for example chalk, gypsum /as in the above mentioned USSR Inventor"s Certificate No. 827424/, or high-molecular organic compounds, for example copolymer of acr-ylamide with methacrylic acid derivatives /see GE Patent Specification No. 1466185, Int. 01. C02C 3/00, 1977/.
Of the major drawbacks of the aforementioned processes is the use of expensive chemical reagents, practically in the complete absence of their regeneration.
The closest prior art has been described in a process for treating a surplus activated sludge, comprising the steps of presettling followed by filtering, avoiding the step of treatment by reagents. Settlings formed as a result of dehydrating the surplus activated sludge are treated just on a filtering cloth with an aqueous alkaline solution or white sulfate liquor. In this case, a highly concentrated alkaline solution of the surplus activated sludge is obtained folowed by its evaporation and sending to burn down /see USSR Inventor's Certificate No. 1038237. Int. Cl. CO2F 11/14, 1933/.
The main disadvantage of the known process consists an low effectiveness and high duration of a process for dehydrating the settlings by filtering, which is caused by an unfavorable structure of said settlings that firmly retain water and have a high specific filtration resist-ance. Moreover, the known process requires the use of expensive alkaline reagents /see Yυ. N. Nelepin, "Sulfate Pulp Production", "Lesnaya Promyshlennost", Moscow, 1990, p. 531/.
SUMMARY OF THE PRESENT INVENTION
The present invention is made in order to solve the above problems included in the prior arts, and an object of this invention is to provide a new process for treating a surplus activated sludge enabling intensification of the process for dehydrating the settlings by filtering, avoiding the use of expensive chemical reagents, a complete utilization of the process products so obtained (a clarified alkaline hydrolyzate and an ash residue) as well as utilization of the sulfate-pulp production waste with minimal costs.
The above technical result is achieved in accordance with the present invention by treating a pre-thickened surplus activated sludge with white slime obtained at the stage of causticizing green liquor in the process of the sulfate-pulp production, with stirring and in a volume ratio of white slime : surplus activated sludge equal to 1 : 5 - 10 followed by dehydration by means of filtering, drying and burning down of the dehydrated settlings.
The present process differs from the known one in that it provides for the treatment of the pre-dehydrated surplus activated sludge with white slime obtained at the stage of causticizing green liquor in the process of the sulfate-pulp production, with stirring and in a volume ratio of white slime : surplus activated sludge equal to 1 : 5 - 10.
White slime used in the present process for treating the surplus activated sludge is a sulfate-pulp production waste being a black suspension with a density of 1.25 - 1.35 Kg/cub. dm and having the following chemical composition, % wt.:
Figure imgf000005_0001
It is common knowledge that upon regeneration of a waste black liquor during the sulfate-pulp process, a fusion cake (a mineral part of the waste black liquor) is formed with sodium carbonate being its main component. Then, the fusion cake is dissolved and green liquor formed therewith is subjected to causticization by adding calcium oxide to obtain a strong white liquor and a calcium carbonate precipitate, that is white slime. Usually, a subsequent utilization of white slime requires its repeated washing with fresh water using special chemical reagents /see USSR Inventor's Certificate No. 827424, C 02 F 11/14, 1981/. The necessity of using fresh water and expensive organic compounds significantly complicates the process and rises its cost.
Using white slime in accordance with the present process allows solution of two problems at once: on the one hand, to intensify and lower the price of the process for treating the surplus activated sludge and, on the other hand, to significantly simplify and lower the price of the process for utilizing white slime.
A process for treating the surplus activated sludge thickened when p-resettling the precipitate, by means of white slime containing alkali residues is accompanied with practically a complete alkaline hydrolysis of the bioorganic part of the sludge (constituting not less than 83 % wt. on dry residue) with the formation of salts of amino acids, amino alcohols and a number of protein derivatives. In turn, calcium carbonate constituting the major contents of white slime, is uniformly distributed, when stirred thoroughly, among undissolved large fibres and solid particles present in the surplus activated sludge in the amount up to 17 % wt. on dry basis. This results in the change of an unfavorable structure of the surplus activated sludge settlings which, under nor-mal conditions (that is, in the absence of treatment with special reagents), firmly retain water and have a high specific filtration resistance. Solid particles and large fibres of the surplus activated sludge join with particles of calcium carbonate and lose water with the formation of a solid phase which is readily separated from an aqueous phase by filtration. Thus, in accordance with the present process, white slime being the sulfate-pulp production waste, on the one hand, replaces an expensive alkaline agent and, on the other hand, performs functions of an auxiliary filtering substance.
The present process is carried out. m the following manner.
The surplus activated sludge is subjected to pre-thickening in a radial or vertical pond. Most preferably, thickening is carried out up to the surplus activated sludge concentration of 18 - 40 g/1. Upon thickening, the surplus activated sludge is fed to a mixer where it is treated with white slime, while stirring. White slime is used in a volume ratio to the surplus activated sludge equal to 1 : 5 - 10 which allows achievement of a maximal efficiency of post-filtering. When treating the sludge with white slime taken in the amount less than that mentioned above, a filtering rate reduces significantly. It is not to the purpose of technology to use white slime in the amounts exceeding the claimed ratio. Most preferably, stirring is carried out at a temperature of between 75 and 104 C. It is also possible to use lower temperatures, up to room temperature, but in this case a process for treating becomes more prolonged. The treatment is carried out to a complete dissolution of a bioorganic part of the surplus activated sludge. Then, a mixture so obtained which contains an alkaline hydrolyzate, undissolved fibres and solid particles present in the surplus activated sludge, as well as calcium carbonate uniformly distributed among the particles of sludge settlings as a result of stirring, are fed to a vacuum filter or a pressure filter and subjected to dehydration. A clarified alkaline hydrolyzate obtained upon filtration may be used, without a subsequent treatment, in the manufacturing cycle of the sulfate-pulp production at the stage of reagent regeneration. A dehydrated precipitate formed on a filter surface is readily removed from the filter surface, thereupon it is subjected to heat drying in drier drums and fed to burn down in an utilization plant furnace. An ash residue comprising calcium oxide is used in the manufacturing cycle of the sulfate-pulp production at the stage of a green liquor causticizing. BEST MODE FOR CARRYING OUT THE INVENTION
To 5 I of an aqueous suspension of the surplus activated sludge having, after settling in a radial pond, a concentration of 80 g/l, 0.75 1 of a white slime suspension is added and thoroughly stirred for 15 minutes at 95 C. A mixture so obtained is fed to a vacuum filter and subjected to dehydration of the settlings. In this case, a filtration rate is determined to be 40 I/sq. m/min. A clarified alkaline hydrolyzate is fed to be used in the manufacturing cycle of the sulfate-pulp production. A dehydrated precipitate formed on a filter surface is removed and subjected to heat drying at 850 C, thereupon it is burned down. An ash residue obtained is fed to the stage of a green liquor causticizing.
INDUSTRIAL APPLILIABILITY
The present process for treating the surplus activated sludge allows intensification of the filtration process, avoiding the use of expensive chemical reagents (at. the expense of using waste of the sulfate-pulp production), a complete utilization of products obtained when treating the sludge (an ash residue and a clarified alkaline hydrolyzate) as well as utilization of the sulfate-pulp production waste, that is white slime, with simplification of the production procedures and techniques and significant reduction of material costs. For the purpose of comparison, a filtration rate in accordance with the known process is 4 l/sq. m/min. Besides, reduction in a dehydration process time according to the present process results in the decrease of energy consumed to realize thereof.

Claims

WHAT IS CLAIMED IS:
1. A process for treating a surplus activated sludge in which the surplus activated sludge is pre-thickened, dehydrated by filtration and the dehydrated settlings are dried and burned down, wherein prior to the stage of filtration, a pre-thickened surplus activated sludge is treated with white slime obtained at the stage of causticizing green liquor in the process of the sulfate-pulp production, with stirring and in a volume ratio of white slime : surplus activated sludge equal to 1 : 5 - 10.
2. A process of claim 1 wherein said thickening is carried out to the surplus activated sludge concentration equal to 13 - 40 g/1.
3. A process of claim 1 or 2 wherein said white slime treatment is carried out at a temperature of between 75 and 104 C.
PCT/RU1996/000032 1995-07-18 1996-02-12 Process for treating a surplus activated sludge Ceased WO1997003928A1 (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
AU46802/96A AU4680296A (en) 1995-07-18 1996-02-12 Process for treating a surplus activated sludge
BR9609736-1A BR9609736A (en) 1995-07-18 1996-02-12 Process for handling an overrun
JP9506587A JPH11510090A (en) 1995-07-18 1996-02-12 Excess activated sludge treatment method
FI980091A FI980091A0 (en) 1995-07-18 1996-02-12 Method for treating surplus activated sludge
EP96902522A EP0842125A1 (en) 1995-07-18 1996-02-12 Process for treating a surplus activated sludge
NO980210A NO980210D0 (en) 1995-07-18 1998-01-16 Process for treating activated sludge excess

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
RU95112218 1995-07-18
RU9595112218A RU2079454C1 (en) 1995-07-18 1995-07-18 Method of processing excessive activated sludge

Publications (1)

Publication Number Publication Date
WO1997003928A1 true WO1997003928A1 (en) 1997-02-06

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PCT/RU1996/000032 Ceased WO1997003928A1 (en) 1995-07-18 1996-02-12 Process for treating a surplus activated sludge

Country Status (11)

Country Link
EP (1) EP0842125A1 (en)
JP (1) JPH11510090A (en)
KR (1) KR19990028251A (en)
CN (1) CN1196033A (en)
AU (1) AU4680296A (en)
BR (1) BR9609736A (en)
CA (1) CA2224683A1 (en)
FI (1) FI980091A0 (en)
NO (1) NO980210D0 (en)
RU (1) RU2079454C1 (en)
WO (1) WO1997003928A1 (en)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE9803384L (en) * 1998-03-02 1999-09-03 Kemira Kemi Ab Process for treating process water
RU2167969C1 (en) * 2000-05-10 2001-05-27 Грудинин Владимир Павлович Method of washing lime sludge of strong white lye
CN1295399C (en) * 2003-12-01 2007-01-17 中国农业科学院土壤肥料研究所 Technology of repairing rock dome using mixed polymer of daily sludge and waste plastics
CA2854292A1 (en) * 2011-11-04 2013-05-10 Valmet Ab Method for the causticizing process for producing white liquor
CN102491618A (en) * 2011-11-29 2012-06-13 曾秀仪 Depth dehydration method for residual sludge
CN106396308B (en) * 2016-10-27 2019-12-31 环境保护部华南环境科学研究所 Recycling method of residual activated sludge
CN109279758B (en) * 2018-11-21 2021-08-10 湖南骏泰新材料科技有限责任公司 Efficient green mud washing method
CN110424179B (en) * 2019-08-26 2021-09-21 华南理工大学 Method for modifying solid waste after incineration of papermaking sludge to be used as papermaking filler
CN112726252B (en) * 2020-11-30 2022-11-25 山东华泰纸业股份有限公司 Comprehensive utilization method of waste residues in paper mill
CN112796144A (en) * 2020-12-28 2021-05-14 山东泗水金立得纸业有限公司 Method for recycling kaolin from sludge of carbon-free copy paper production line

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1466185A (en) * 1973-03-07 1977-03-02 Andco Inc Dewatering of slimes
US4030968A (en) * 1975-12-22 1977-06-21 Consolidated-Bathurst Limited Disposal of paper pulp mill sludge
US4240904A (en) * 1977-06-27 1980-12-23 Stamicarbon, B.V. Process for biological purification of waste water
GB2066304A (en) * 1979-11-20 1981-07-08 Vn Proizv Ob Celljuloszno Method for recovery of wastewater residues
SU1038287A1 (en) * 1979-11-20 1983-08-30 Всесоюзное научно-производственное объединение целлюлозно-бумажной промышленности Method of treating excessive active slurry

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1466185A (en) * 1973-03-07 1977-03-02 Andco Inc Dewatering of slimes
US4030968A (en) * 1975-12-22 1977-06-21 Consolidated-Bathurst Limited Disposal of paper pulp mill sludge
US4240904A (en) * 1977-06-27 1980-12-23 Stamicarbon, B.V. Process for biological purification of waste water
GB2066304A (en) * 1979-11-20 1981-07-08 Vn Proizv Ob Celljuloszno Method for recovery of wastewater residues
SU1038287A1 (en) * 1979-11-20 1983-08-30 Всесоюзное научно-производственное объединение целлюлозно-бумажной промышленности Method of treating excessive active slurry

Also Published As

Publication number Publication date
BR9609736A (en) 1999-12-21
FI980091A7 (en) 1998-01-16
JPH11510090A (en) 1999-09-07
CN1196033A (en) 1998-10-14
EP0842125A1 (en) 1998-05-20
FI980091L (en) 1998-01-16
CA2224683A1 (en) 1997-02-06
AU4680296A (en) 1997-02-18
RU2079454C1 (en) 1997-05-20
KR19990028251A (en) 1999-04-15
NO980210L (en) 1998-01-16
NO980210D0 (en) 1998-01-16
FI980091A0 (en) 1998-01-16

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