WO1989011455A1 - Process and device for conditioning sludges which are difficult to de-water - Google Patents

Process and device for conditioning sludges which are difficult to de-water Download PDF

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Publication number
WO1989011455A1
WO1989011455A1 PCT/EP1989/000536 EP8900536W WO8911455A1 WO 1989011455 A1 WO1989011455 A1 WO 1989011455A1 EP 8900536 W EP8900536 W EP 8900536W WO 8911455 A1 WO8911455 A1 WO 8911455A1
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WO
WIPO (PCT)
Prior art keywords
sludge
conditioning
electrodes
direct voltage
water
Prior art date
Application number
PCT/EP1989/000536
Other languages
German (de)
English (en)
French (fr)
Inventor
Alfons KÖHLING
Rolf-Erhard Schmitt
Evangelos Gidarakos
Bernhard Fischer
Original Assignee
Battelle-Institut E.V.
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 Battelle-Institut E.V. filed Critical Battelle-Institut E.V.
Publication of WO1989011455A1 publication Critical patent/WO1989011455A1/de

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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
    • C02F1/48—Treatment of water, waste water, or sewage with magnetic or electric fields
    • 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
    • C02F11/15—Treatment of sludge; Devices therefor by de-watering, drying or thickening by treatment with electric, magnetic or electromagnetic fields; by treatment with ultrasonic waves

Definitions

  • the invention relates to a method and a device for conditioning sludge that is difficult to drain with the aim of influencing the drainage behavior in a positive sense.
  • Sludges from wastewater treatment plants occur with a high water content, which among other things depends on the processes used and the type and size of the solid particles. Sewage sludge from municipal wastewater treatment plants is thin and normally has a solids content of 1 to 5%. In this consistency, disposal is uneconomical and in most cases also not in accordance with the regulations. The sludge is therefore further dewatered into a solid waste product.
  • the sludge is kept in reactors for a period of 30 minutes at temperatures up to approximately 220 ° C. and pressures up to approximately 20 bar and then cooled to 60 ° C.
  • a filter cake is obtained with 45 to 55% "solids.
  • the disadvantage of this method is the high energy requirement and the need for pressure vessels.
  • lime milk and iron or aluminum salt solutions are mixed with the sludge, in some cases also organic flocculants.
  • the drainability can hereby be improved to such an extent that filter cakes with 20 to 30% solids are obtained in vacuum cell filters and those with 30 to 50% solids are obtained in filter presses.
  • a disadvantage of this process is the need for chemical additives, the resulting salting of the water and the need for measuring and regulating devices for monitoring the conditioning; an overdose leads to resuspension of the sludge.
  • a disadvantage of this process is that only charged particles migrate here and the rate of migration depends on the type and size of the particles. This can lead to the fact that with a wide particle size distribution, as is to be expected in waste sludge, small particles lead to blockage of the diaphragm, while larger particles are hardly involved in the migration. This means a strong limitation of the area of application.
  • the porosity must be so high that the Voltage losses remain low, on the other hand, the pores must not be so large that the particles can migrate through the diaphragm. Even during a long period of operation, the properties should not change due to contamination or other factors.
  • German patent application P 37 39 580.7-45 of November 23, 1987 describes a method and a device for splitting an aqueous emulsion which is subjected to a DC voltage in an electrochemical cell for this purpose. Sludge should not be conditioned with this procedure.
  • G3-PS 1 527 692 proposes to expose this to an electrical DC voltage for the treatment of water, which is superimposed on an AC voltage. Slurries cannot be conditioned using this procedure because the anode is isolated. The electrodes there act much more as a capacitor.
  • the present invention is therefore based on the object of overcoming the disadvantages of the known processes and of developing a process which allows waste sludges with different charge of the particles and a broad particle size distribution to be treated in such a way that Drainage behavior is influenced in a positive sense.
  • the process is said to be largely insensitive to contamination.
  • the inventors found that, in particular, highly organically contaminated sludges, such as those from municipal, sewage treatment plants, without any prior preparation with chemical agents, could be influenced in a very short time by the action of the electrical direct voltage field with sufficiently large electrode areas so that their sedimentation behavior and their filterability were considerably improved.
  • the device for carrying out the method according to the invention is technically simple and can be implemented with little effort.
  • it preferably has only one separator for protecting the cathode.
  • No special requirements are to be made of the DC voltage source, which must provide relatively low voltage values.
  • the DC voltage can optionally remain constant or alternate during the treatment, or an AC voltage can be superimposed on it, for example at a frequency of approximately 50 kHz to 100 kHz.
  • the method according to the invention offers the possibility of extraordinarily fast conditioning, which, in addition to conditioning in batch operation, makes continuous flow through the chemical cell with direct transfer of the sludge for further processing only practical.
  • Fig. 1 schematically a first embodiment of a device for conditioning sludge
  • Fig. 2 - a diagram with the results obtained with the arrangement according to Fig. 1 with regard to filtration properties;
  • FIG. 3 shows a diagram with the results obtained with the arrangement according to FIG. 1 with regard to the sedimentation behavior
  • water-containing sludge flows from a storage vessel 1 by gravity to an electrochemical cell 3 until it is filled to a predetermined height.
  • the electrochemical cell 3 contains two electrodes 4 and 5, which are connected via terminals 6 and 7 to the poles of a DC voltage source.
  • the electrodes can be formed as a sheet or mesh; they are advantageously characterized by a high specific surface area. For this purpose, for example, several networks can be combined to form an electrode packet. It is also preferred if the electrodes are made of a corrosion-resistant material. This prevents the electrodes from corroding or dissolving.
  • nickel and graphite and platinized titanium, tantalum and niobium are also suitable as electrode material for the positive electrode (anode). Titanium, graphite, stainless steel, etc. are used for the negative electrode (cathode). suitable.
  • a voltage is applied to the electrodes, which is adjusted so that a predetermined limit value is not exceeded.
  • the dewatering properties of the sludge are influenced in a positive way by the action of the electrical field in the cell; probably through the formation of larger sludge aggregates, releasing adhering water.
  • the sludge conditioned in this way has a lower water binding capacity than sludges from conventional water treatment. So that will be Sedimentation, thickening and drainage behavior improved.
  • the residence time of the sludge in the cell is chosen so that the sludge has achieved the desired properties.
  • the conditioned sludge then arrives in a buffer container 8 and is passed on from there for further treatment, such as sludge thickening and / or water separation.
  • the method can also be carried out in such a way that a separator 9 is provided in the cell 3 between the electrodes 4 and 5. It is advantageously arranged in such a way that the negative electrode is protected from direct flow of sludge particles. For example, large-mesh plastic nets are suitable as materials for this.
  • the drainage behavior is determined as a criterion for the efficiency of the process. For this purpose, the filtration and sedimentation behavior were measured.
  • Important parameters of the filtration behavior are the filtration speed and the Fil ratmer.ee. To determine these parameters, a measured amount of sludge from 50 to 100 ml was placed on a filter, Filtered under gravity and the filtrate measured closely as a function of time.
  • Important characteristics of the sedimentation behavior are the sedimentation speed and the volume of the sludge that is segmented. To determine these parameters, a measured amount of sludge was poured into a cylinder and the sedimentation under the influence of gravity was measured as a function of time.
  • FIG. 4 A preferred embodiment of a device is shown in FIG. 4.
  • the electrochemical cell is the same structure as in Fig. 1 with respect thereto, and it uses pay v / ground the same reference ⁇ .
  • the electrodes are in this leadership form horizontally arranged, the positive electrode 4 is located in the lower region of the cell 3 below the negative electrode 3.
  • several metal nets stacked one above the other are used for the positive electrode.
  • the water-containing sludge flows out of the storage vessel 1 by gravity or with the aid of a pump 2 to the electrochemical cell 3.
  • the flow rate is predetermined by a valve or by a delivery rate of the pump, pumps which are to be used which Do not break pre-formed mud flakes.
  • a DC voltage source is applied to current connections 6 and 7 and the voltage is regulated in such a way that a predetermined current, which depends on the type of sludge, is not exceeded.
  • the treatment time of the sludge corresponds essentially to the dwell time in the process shown in FIG. 1, but can advantageously be varied more easily here, for example by changing the flow rate.
  • the conditioned sludge 'then flows into the buffer vessel 8 and is further treated on closing.
  • the filtrate is also clearly clearer, an indication that in particular organic suspended matter and colloids have accumulated on large particles or have combined to form larger agglomerates.
  • the sedimentation behavior is also positively influenced. While untreated sludge partially sediments and partially floats, the treatment causes all of the solids to sediment. This changed sedimentation behavior indicates that larger, heavier sludge particles have formed.
  • an electrode with a large geometric surface was installed for the positive side (anode).
  • four chrome-nickel wire networks were combined to form an electrode package; the geometric top
  • Example 2 similarly good results as described in Example 1 can be obtained with a lower voltage and a shorter treatment time.
  • 200 ml of sewage sludge 1 were treated with a voltage of 4 V for a period of 30 minutes.
  • the test result is shown as curve III in FIG. 2.
  • the sedimentation behavior was determined to characterize the sludge properties. For this purpose, v / ere 100 ml of treated sludge in a cylindrical glass vessel was added and the decrease 'of the sludge level as a function of time measured. The initial height of the sludge was 40 mm. The same amount of untreated sludge was used for comparison.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Treatment Of Sludge (AREA)
  • Water Treatment By Electricity Or Magnetism (AREA)
PCT/EP1989/000536 1988-05-27 1989-05-17 Process and device for conditioning sludges which are difficult to de-water WO1989011455A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE3818038 1988-05-27
DEP3818038.3 1988-05-27
DEP3824289.3 1988-07-16
DE3824289A DE3824289A1 (de) 1988-05-27 1988-07-16 Verfahren und vorrichtung zur konditionierung schwer entwaesserbarer schlaemme

Publications (1)

Publication Number Publication Date
WO1989011455A1 true WO1989011455A1 (en) 1989-11-30

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1989/000536 WO1989011455A1 (en) 1988-05-27 1989-05-17 Process and device for conditioning sludges which are difficult to de-water

Country Status (2)

Country Link
DE (1) DE3824289A1 (enrdf_load_stackoverflow)
WO (1) WO1989011455A1 (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996006804A1 (en) * 1994-08-29 1996-03-07 Raision Tehtaat Oy Ab Method for dewatering sludges

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4212322A1 (de) * 1992-04-13 1993-10-14 Battelle Institut E V Verfahren zur Entfernung von Quecksilber und anderen Schwermetallen aus Erdreich und Schlämmen
DE4442565A1 (de) * 1994-11-30 1996-06-05 Goes Ges Fuer Sanierungsmasnah Verfahren zum Dekontaminieren und/oder Entwässern von wässrigen, ligninhaltigen Schlämmen
EP1504814A1 (en) * 2003-08-07 2005-02-09 Gloryquest Holdings Limited Method for the qualitative improvement of the organic and inorganic matter with the use of electromagnetic noise
CA2758872A1 (en) 2011-04-07 2012-10-07 Dpra Canada Incorporated Electrokinetic process and apparatus for consolidation of oil sands tailings
AU2014334447A1 (en) * 2013-10-07 2016-05-19 Electro-Kinetic Solutions Inc. Method and apparatus for treating tailings using an AC voltage with a DC offset
DE102018205630A1 (de) * 2018-04-13 2019-10-17 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Mikroreaktor für photokatalytische Reaktionen
CN111825265A (zh) * 2019-04-23 2020-10-27 中国石油化工股份有限公司 油田采出水处理方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR857752A (fr) * 1940-04-10 1940-09-28 Appareil pour le traitement des liquides par voie électronique
FR2106286A5 (enrdf_load_stackoverflow) * 1970-09-15 1972-04-28 Battelle Memorial Institute

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1658071A1 (de) * 1967-06-29 1971-11-18 Hartkorn Karl Heinz Verfahren und Einrichtung zur Reinigung von Abwasser und Behandlung der anfallenden Schlaemme
EP0046155A1 (en) * 1980-08-14 1982-02-24 Innova, Inc. Process and apparatus for slime and sludge dewatering
US4367132A (en) * 1980-08-27 1983-01-04 Electro-Petroleum, Inc. Method for removing liquid from chemically-precipitated sludge

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR857752A (fr) * 1940-04-10 1940-09-28 Appareil pour le traitement des liquides par voie électronique
FR2106286A5 (enrdf_load_stackoverflow) * 1970-09-15 1972-04-28 Battelle Memorial Institute

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996006804A1 (en) * 1994-08-29 1996-03-07 Raision Tehtaat Oy Ab Method for dewatering sludges
US5827432A (en) * 1994-08-29 1998-10-27 Raision Tehhtaat Oy Ab Method for dewatering sludges

Also Published As

Publication number Publication date
DE3824289A1 (de) 1989-11-30
DE3824289C2 (enrdf_load_stackoverflow) 1992-05-27

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