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WO1992003385A1 - Procede de traitement d'eaux usees ou impures et adjuvant floculant correspondant - Google Patents

Procede de traitement d'eaux usees ou impures et adjuvant floculant correspondant Download PDF

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Publication number
WO1992003385A1
WO1992003385A1 PCT/FI1991/000257 FI9100257W WO9203385A1 WO 1992003385 A1 WO1992003385 A1 WO 1992003385A1 FI 9100257 W FI9100257 W FI 9100257W WO 9203385 A1 WO9203385 A1 WO 9203385A1
Authority
WO
WIPO (PCT)
Prior art keywords
biosludge
flocculating
waste water
waters
sludge
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/FI1991/000257
Other languages
English (en)
Inventor
Pertti Kalevi Hynninen
Ilkka Seppo Olavi Nevalainen
Pertti Juhani Vuoriranta
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.)
ENVIRO DATA Oy
Original Assignee
ENVIRO DATA Oy
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 ENVIRO DATA Oy filed Critical ENVIRO DATA Oy
Publication of WO1992003385A1 publication Critical patent/WO1992003385A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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
    • C02F1/34—Treatment of water, waste water, or sewage with mechanical oscillations
    • C02F1/36—Treatment of water, waste water, or sewage with mechanical oscillations ultrasonic vibrations
    • 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
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5263—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using natural chemical compounds
    • 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

Definitions

  • the present invention concerns a process in accordance with the preamble of claim 1 for the treatment of waste waters or equivalent impure waters.
  • the water which is to be treated is admixed in a mixing zone with a componen which provides flocculation of the organic substance.
  • the mixture obtained from the mixing process is then introduced into a separation zone for separation of the flocculating substance from the liquid, and, finally, the treated effluen is conducted to a further treatment, if any.
  • the process in accordance with the invention is suitable for the treatment of waste waters stemming from, in particular, the pulp and paper industry, but it can also be used for purification of other industrial waste waters, such as waste waters from the oil refining industry and the polymer industry as well as fcr purification of municipal waste waters.
  • the invention also relates to a flocculating adjuvant for treatment of waste waters cr equivalent impure waters.
  • the biological sludge There is no economically interesting use for the biological sludge.
  • it is either dried and combusted together with the fibrous sludge or it is transported to a land filling area and dumped.
  • the microorganisms contained in the activated sludge are not either being utilized.
  • phosphorous and nitrogeneous compounds bound to the sludge have been recovered. These substances have been re- utilized in biological purification processes.
  • the present invention is based on the idea of using the activated sludge as a flocculating adjuvant in the primary clarification stage of waste water purification.
  • the activated sludge is often removed from the process together with sludge from the primary clarifier by introducing the biosludge together with the water into the primary clarification.
  • a part of the biosludge may, however, float to the surface if the conditions of the waste ' water are anaerobic.
  • the biosludge may also float to the surface because of other reasons. Generally, the solids removal in the primary clarification stage is therefore impaired.
  • the process in accordance with the invention is characterized by what is stated in the characterizing part of claim 1.
  • the flocculating adjuvant is characterized by what is state in the characterizing part of claim 7.
  • biosludge means a sludge which conteins proteins and stems from a waste water purification plant, such as an activated sludge plant or an aerated stabilisation basin. It also contains living and dead micrcorganisms.
  • flocculation and "precipitation” are inter ⁇ changeably used to indicate processes in which dissolved substances are brought into solid state, thus separating from the solution.
  • the solid substance formed during precipitation may coagulate forming flings and floes which, depending on the process conditions, either are deposited on the bottom or - in flotation - float to the surface.
  • the terms “flocculation” and “precipitation” cover the processes in which flings and floes are formed and are coagulated.
  • the flocculating adjuvant is added to the waste water which is to be treated in the primary clarification stage of an activated sludge process or in an equivalent preliminary treatment of a waste water purification process intended for removing dissolved matter, solids and colouring com ⁇ pounds from the waste waters.
  • the biosludge is added in order to improve the separation efficiency of the process, but it may even in some cases completely substitute the flocculating agent normally used.
  • the pH may be adjusted with a suitable acid, in particular a mineral acid, such as hydrochloric acid, nitric acid or sulphuric acid. It is, however, possible to use acidic waste water fractions, such as ferrous sulphate containing waste waters. Since the pH of these liquids often is rather low, even less than 1, they are in particular suitable for adjusting the pH of waste waters from the alkaline stage of pulp bleaching to a desired value. According to the invention, the pH should be kept below about 3 to provide precipitation. As the examples below will show, the process does not achieve the desired result at a pH value of about 4. Due to economical reasons it is, on the other hand, seldom sensible to lower the pH below 2, even if the process works in that pH range as well.
  • a suitable acid in particular a mineral acid, such as hydrochloric acid, nitric acid or sulphuric acid.
  • acidic waste water fractions such as ferrous sulphate containing waste waters. Since the pH of these liquids often is rather low, even
  • the biosludge is added to the waste water in a mixing zone, the waste water being mixed, e.g., in successive mixing containers.
  • the mixture formed by the treated sludge and the waste water is mixed in two stages, first under strong agitation and then under slow agitation. The two stages are performed in different mixing vessels.
  • At least a part of the microorganism cells preferably at least about 50 %, and in particular about 60 % to 90 % of the microorganism cells of the biosludge adjuvant are crushed by a suitable crushing treatment before the adjuvant is admixed with the waste water.
  • the biosludge is treated in a sonicator by ultrasonic sound.
  • the microorganism cells are crushed by subjecting the sludge to an increased pressure which is rapidly relieved (explosion technique).
  • the uncrushed solid substance may be removed by filtering or centrifugation.
  • the consistency of the biosludge added to the waste water is then about 0.2 %, but it can be raised to about 2 to 3 % by concentrating the sludge.
  • the amount of flocculant needed for providing precipitation depends on the amount of dissolved and suspended compounds of the waste water. Normally, the amount of dry substance of the treated biosludge adjuvant added amounts to from about 0.2 to 1.5 g per litre of waste water. Under the acidic conditions mentioned above (pH below about 3) the biosludge, which primarily comprises dissolved substances, will coagulate, thus flocculating and precipitating the organic substance contained in the waste water.
  • flocculants in addition to the treated biosludge, flocculants know per se may be used in the process according to the invention. These flocculants include, e.g., ferrous and ferric sulphate and aluminium sulphate. They can be added, for instance, in the form of aqueous solutions containing ferrous, ferric and/or aluminium ions.
  • ferrous and ferric sulphate and aluminium sulphate e.g., ferrous and ferric sulphate and aluminium sulphate. They can be added, for instance, in the form of aqueous solutions containing ferrous, ferric and/or aluminium ions.
  • ferrous waste water of the chemical industry e.g., ferrous waste water of the chemical industry.
  • flocculating adjuvant in addition to the treated biosludge, another flocculating adjuvant together with the flocculant, if any.
  • This flocculating adjuvant known per se can, depending on the composition of the waste water, be comprised of differen cationic polymers, anionic polymers and polyelectrolytes. It can be added to the waste water before the addition of the biosludge or, alternatively, after the addition thereof, or simultaneously with it.
  • the flocculating substance and the effluent are separated by conducting the mixture of the waste water and sludge, for instance, to the equalization basin or to the aeration basin of an activated sludge plant, wherein the flocculating substance is separated by methods known per se.
  • biosludge 5 comprising surplus sludge of the activated sludge process is crushed in crushing unit 1 and used in primary clarification as a flocculating adjuvant.
  • the crushing process is carried out, for instance, by subjecting the sludge to high pressure which is rapidly relieved (the 0 explosion technique) or by sonication.
  • the waste water which is to be treated is admixed in a first mixing vessel 2 with the crushed biosludge.
  • the sludge is fed to the treated waste water in an amount corresponding to 0.2 to 1.5 g solid substance (calculated as evaporation residue) per 5 litre of water conducted to the clarification.
  • the pH of the waste water is adjusted by adding an acidic waste water fraction or by adding a mineral acid (sulphuric acid or a similar acid) such that the pH lies in the range from 2 to 3.
  • the pH of the mixture is 0 measured and adjusted by means of control device 3, comprising means for indicating, registering and controlling the pH (QIRC) and means for indicating, registering and controlling the amount of acid feed (FIRC) .
  • the treated waste water is agitated, first rapidly for 1 to 2 minutes in the first mixing vessel 2, and then slowly for 6 to 10 minutes in a second mixing vessel 4.
  • the biosludge will then coagulate and the sludge and the organic substances of the waste water will begin to flocculate and precipitate.
  • the mixture of adjuvant and waste water is fed to a clarifier or to a flotation apparatus 6. If the equipment used for separating the water from the floes contain construction parts made from concrete or other parts which are susceptible to acid induced corrosion, the pH of the mixture should be raised to from about .8 to about 5.3 by adding, for instance, lime (an aqueous solution of calcium hydroxide), which is introduced in the middle vessel 5.
  • the pH of the mixture conducted to the clarifier is controlled in the above-described way by using control means 3.
  • a clarifier 6 Conventionly dimensioned for clarification of waste waters in the pulp and paper industry, will be needed (surface load 0.6...1.2 m 3 /m 2 , delay time 3 to 5 hours) .
  • the surface load may be from about 3 to about 5 m 3 /m 2 h and the volume of water known as dispersion water may be from 10 to 20 % of the amount of treated water.
  • the waste water is conducted from clarification 6 to the biological purification stage.
  • the sludge is fed to the sludg treatment and treated together with other sludges of the waste water treatment by methods known per se.
  • the waste water used in this example was comprised of waste water from a chemimechanical pulping mill (CTMP), which was introduced into a primary clarifier. During pulping, spruce had been used as raw material of the pulp.
  • the biosludge used in the example consisted of biological sludge from the activated sludge process of the same ' mill. The biological sludge was sonicated and the solid material left was removed by centrifugation. A standard amount of biological sludge was added to the waste water. The pH of different samples was adjusted by dilute sulphuric acid to different values. After the addition of the acid, the samples were agitated at constant speed for about 10 minutes and the samples were then allowed to settle for about 30 minutes. Samples of the aqueous phases were then taken and the solids content was determined by using a GF/A filter. The results are indicated in the following table 1.
  • the reduction of the solids content has been calculated on basis of the solids content of the original waste water.
  • Softwood pulp prepared by the kraft process to Kappa-number 31 was bleached on laboratory scale by using the bleaching sequence C/D E1DE2D. The aim was to attain brightness ISO 90.
  • the waste water of the alkaline stage (stage E ] _ ) , the acidic waste water (stage C/D, wherein C stands for chlorin and D for chlorine dioxide) and biosludge which had been sonicated, crushed and filtered were mixed, the sludge bein introduced together with the acidic acidic waste water into the alkaline waste water under agitation. The mixture was mixed for 5 minutes and then it was allowed to settle for about 1 hour. A sample was taken of the water and the colour was determined at constant pH. The results are given in the enclosed table 2.
  • the volumetric ratios of the alkaline water to acidic water to biosludge were 1:2:0.2.

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

Abstract

Procédé de traitement notamment des eaux usées produites par l'industrie de la pâte à papier et du papier, et adjuvant floculant utilisé dans ce procédé. Lors de l'étape de clarification primaire, on ajoute aux eaux usées des boues biologiques provenant d'un processus d'activation de boues ou d'un bassin de stabilisation à activation de boues, afin de provoquer la floculation. Avant leur introduction dans les eaux usées, on broie au moins une partie, de préférence au moins 50 % et notamment au moins 60 %, des cellules de microorganismes présentes dans les boues biologiques. Afin de provoquer la floculation et la précipitation des substances organiques comprises dans les boues biologiques et dans les eaux usées, on amène le pH à une valeur comprise entre 2 et 3. Grâce à ce procédé, on peut remplacer au moins une partie des floculants normalement utilisés lors de l'étape de clarification du processus d'épuration des eaux usées.
PCT/FI1991/000257 1990-08-17 1991-08-19 Procede de traitement d'eaux usees ou impures et adjuvant floculant correspondant Ceased WO1992003385A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI904070 1990-08-17
FI904070A FI90856C (fi) 1990-08-17 1990-08-17 Menetelmä jäteveden tai sentapaisen epäpuhtaan veden käsittelemiseksi sekä menetelmässä käytettävä saostuksen apuaine

Publications (1)

Publication Number Publication Date
WO1992003385A1 true WO1992003385A1 (fr) 1992-03-05

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PCT/FI1991/000257 Ceased WO1992003385A1 (fr) 1990-08-17 1991-08-19 Procede de traitement d'eaux usees ou impures et adjuvant floculant correspondant

Country Status (3)

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AU (1) AU8314391A (fr)
FI (1) FI90856C (fr)
WO (1) WO1992003385A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1993025479A1 (fr) * 1992-06-18 1993-12-23 Universite Libre De Bruxelles Procede d'elimination de derives hydrocarbones polycycliques et/ou aliphatiques presents dans les effluents industriels
EP0960860A1 (fr) * 1998-05-21 1999-12-01 Shell Internationale Researchmaatschappij B.V. Traitement biologique d'un courant d'eau polluée
KR100441112B1 (ko) * 2001-10-08 2004-07-21 한국해양연구원 최소수선단면을 갖는 삼동선형 위그선
WO2019158813A1 (fr) * 2018-02-16 2019-08-22 Upm-Kymmene Corporation Procédé de traitement de boues biologiques

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3406114A (en) * 1964-07-20 1968-10-15 Kerr Mc Gee Oil Ind Inc Process for flocculating finely divided solids suspended in an aqueous medium with amicrobial polysaccharide
DE1459469A1 (de) * 1962-01-31 1969-07-10 Eltro Gmbh Verfahren zur Behandlung von Klaerschlamm
US4649110A (en) * 1982-07-29 1987-03-10 Solmat Systems, Ltd. Polymeric substance, and method of separating and culturing bacteria to provide polymeric substance useful in liquid clarification and soil conditioning
US4721570A (en) * 1986-02-06 1988-01-26 Envirex, Inc. RBC with solids contact zone

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1459469A1 (de) * 1962-01-31 1969-07-10 Eltro Gmbh Verfahren zur Behandlung von Klaerschlamm
US3406114A (en) * 1964-07-20 1968-10-15 Kerr Mc Gee Oil Ind Inc Process for flocculating finely divided solids suspended in an aqueous medium with amicrobial polysaccharide
US4649110A (en) * 1982-07-29 1987-03-10 Solmat Systems, Ltd. Polymeric substance, and method of separating and culturing bacteria to provide polymeric substance useful in liquid clarification and soil conditioning
US4721570A (en) * 1986-02-06 1988-01-26 Envirex, Inc. RBC with solids contact zone

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, Volume 96, No. 20, 17 May 1982, (Columbus, Ohio, US), HALL T.: "Sonication for the study of floc strength and reflocculation of activated sludge", see page 350, abstract 168011k; & ENVIRON. TECHNOL. LETT. 1981, 2, 579-588. *
PATENT ABSTRACTS OF JAPAN, Vol. 12, No. 128, C489; & JP,A,62 247 888, 28-10-1987, (SHIN ETSU HANDOTAI CO LTD). *
PATENT ABSTRACTS OF JAPAN, Vol. 6, No. 231, C135; & JP,A,57 132 586, 16-08-1982, (MITSUBISHI JUKOGYO K.K.). *
PATENT ABSTRACTS OF JAPAN, Vol. 8, No. 283, C258; & JP,A,59 150 591, 28-08-1984, (HITACHI PLANT KENSETSU K.K.). *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1993025479A1 (fr) * 1992-06-18 1993-12-23 Universite Libre De Bruxelles Procede d'elimination de derives hydrocarbones polycycliques et/ou aliphatiques presents dans les effluents industriels
EP0960860A1 (fr) * 1998-05-21 1999-12-01 Shell Internationale Researchmaatschappij B.V. Traitement biologique d'un courant d'eau polluée
KR100441112B1 (ko) * 2001-10-08 2004-07-21 한국해양연구원 최소수선단면을 갖는 삼동선형 위그선
WO2019158813A1 (fr) * 2018-02-16 2019-08-22 Upm-Kymmene Corporation Procédé de traitement de boues biologiques

Also Published As

Publication number Publication date
AU8314391A (en) 1992-03-17
FI90856C (fi) 1994-04-11
FI904070L (fi) 1992-02-18
FI90856B (fi) 1993-12-31
FI904070A0 (fi) 1990-08-17

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