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WO1996034833A1 - Procede et dispositifs permettant d'ameliorer l'aptitude a la deshydratation mecanique de boues de curage - Google Patents

Procede et dispositifs permettant d'ameliorer l'aptitude a la deshydratation mecanique de boues de curage Download PDF

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Publication number
WO1996034833A1
WO1996034833A1 PCT/DE1996/000740 DE9600740W WO9634833A1 WO 1996034833 A1 WO1996034833 A1 WO 1996034833A1 DE 9600740 W DE9600740 W DE 9600740W WO 9634833 A1 WO9634833 A1 WO 9634833A1
Authority
WO
WIPO (PCT)
Prior art keywords
sludge
freezing
thawing
mechanical
sewage 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/DE1996/000740
Other languages
German (de)
English (en)
Inventor
Klaus Ulrich Plantikow
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.)
Sep Gesellschaft fur Technische Studien Entwicklung Planung MbH
Original Assignee
Sep Gesellschaft fur Technische Studien Entwicklung Planung MbH
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 Sep Gesellschaft fur Technische Studien Entwicklung Planung MbH filed Critical Sep Gesellschaft fur Technische Studien Entwicklung Planung MbH
Priority to AU56437/96A priority Critical patent/AU5643796A/en
Publication of WO1996034833A1 publication Critical patent/WO1996034833A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • 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
    • C02F11/18—Treatment of sludge; Devices therefor by thermal conditioning
    • C02F11/20—Treatment of sludge; Devices therefor by thermal conditioning by freezing

Definitions

  • the invention relates to a method for improving the mechanical dewaterability of aqueous sludges with a considerable microbial content and devices for carrying out the method.
  • sludges occur in very large quantities, particularly in municipal sewage treatment plants, but also in agriculture and in the treatment of industrial waste water in waste water treatment plants with at least one biological treatment stage. Representing such sludges, the invention is described below for sewage sludge from the disposal of municipal wastewater.
  • Sewage sludge is so difficult to dewater mechanically because the cell water bound within the cells of the microorganisms cannot be removed with the usual presses and centrifuges and the water contained in the slime layers on the surface of the microorganisms can be removed at most to a small extent.
  • An aerobic or anaerobic stabilization improves the dewaterability, since the biomass and thus the amount of cell water is reduced and because the ratio of organic mass to inorganic mass in the sludge is thereby reduced.
  • the best results in terms of low odor and improvement in drainability are obtained with the mesophile Digestion of sewage sludge, ie during anaerobic digestion at approx. 35 ° C.
  • the invention has for its object to improve the mechanical dewaterability of aqueous sludges with a considerable microbial content, in particular of municipal sewage sludge, and to avoid the disadvantages of the known methods for improving dewaterability.
  • the first stage of the mechanical dewatering most of the water contained in the sludge between the microorganisms is removed, and in the second stage cell water is additionally removed from the cells destroyed by the freezing process.
  • mechanical dewatering devices of different designs and sizes adapted to the respective sludge properties can be used.
  • the water separated in the second stage is particularly nutrient-rich due to the contents of the cell water and therefore has a particularly high biological oxygen requirement. An introduction into a digestion tower, if there is one, is therefore more advantageous than introducing this water into the activated sludge basin of the sewage treatment plant.
  • the injury according to the invention to the cell walls of the microorganisms contained in the sludge is also advantageous for thermal drying.
  • the process according to the invention can also considerably improve the mechanical dewaterability of excess activated sludge, which is far more difficult to dewater than digested sludge.
  • the time-consuming aerobic or anaerobic stabilization of the sludge and the expensive devices for carrying out such sludge stabilization are not required in this case.
  • the proportion of inorganic substances in the excess sludge of municipal sewage treatment plants is typically about 1/3 before digestion and about 1/2 after digestion, the application of the process according to the invention to excess activated sludge and subsequent thermal drying also gives a larger amount of fuel with a higher calorific value than when used on digested sewage sludge.
  • the dried sewage sludge can be used to substitute fossil fuels, for example when used in cement kilns, asphalt mixing plants, waste incineration plants, etc.
  • the slag resulting from the combustion of the sewage sludge can also be used mixed with the raw materials and thus used.
  • auxiliaries such as coal dust or polymers for the conditioning, by means of which the calorific value of the dried sludge does not deteriorate but rather The opposite is improved.
  • the process according to the invention is also suitable for sludge to which no conditioning agents have been added.
  • FIGS. 1 and 2 which are described in more detail below, have some special advantages.
  • FIG. 1 shows schematically the essential parts of a system for freezing and thawing pre-dewatered sewage sludge 1.
  • This sludge is applied to a conveyor belt 3 from a storage container 2 with the aid of a conveyor device not shown in FIG. 1, for example a thick matter pump.
  • this conveyor belt has a high proportion of gaps, as is the case, for example, with wire link belts.
  • the mesh size is chosen so small that no sludge falls through the mesh. Since a puncture-resistant sludge can be produced with various of the drainage devices normally used, this requirement can be met without difficulty.
  • the sludge applied to the conveyor belt 3 is frozen using a refrigeration system.
  • the conveyor belt is moved with the aid of a drive device (not shown in FIG.
  • the sludge which is generally frozen on the conveyor belt, does not have to be rearranged for thawing.
  • the sludge passes into a container 5 via a discharge device 4, which also contains a conveying device which may be necessary but is not shown in FIG. 1, for example a thick matter pump Device for mechanical drainage 6 supplied.
  • the sludge 7 dewatered in this device 6 can, for example, be a device for thermal drying are fed, and the separated water 8 can, for example, be returned to the sewage treatment plant or passed into a digestion tower which may be present.
  • the freezing and thawing process is carried out with the aid of a compression refrigeration system with a compressor 9, a condenser 10, an evaporator 11 and an expansion valve 12.
  • the heat required to evaporate the refrigerant is supplied to the evaporator by circulating air, which extracts the corresponding heat from the sludge on the conveyor belt.
  • the speed of the conveyor belt 3 and the layer height of the sludge on the conveyor belt are set so that the sludge completely freezes in the freezing area.
  • the air is circulated in the freezing area by fans, which are usually components of air-cooled refrigeration system evaporators 11. If these fans are not sufficient to generate an adequately large air flow, an additional fan, which is not shown in FIG. 1, can be installed.
  • ambient air 13 is passed through the condenser 10 of the refrigeration machine and is thereby heated. With the help of the heated air, the sludge is thawed.
  • the heat output transmitted on the condenser 10 corresponds to the sum of the cooling output transmitted on the evaporator 11 and the compressor output. A greater heat output is therefore available than is required for thawing.
  • the air used for thawing is not completely saturated with water vapor, a small amount of water is also extracted from the sludge during the thawing process.
  • the air can be circulated as in the freezing area. A circulation of the air in the thawing area is advantageous if the exhaust air from this area has to be cleaned.
  • the sludge should lie as loosely as possible with a crumbly structure on the conveyor belt so that the air can flow through the sludge layer without difficulty.
  • a crumbly structure can generally be achieved with mechanical sewage sludge dewatering. If there is no crumbly structure at the outlet of a conveyor device installed between the storage container 2 and the conveyor belt 3, such a structure can be produced by simple comminution devices downstream of the conveyor device, for example perforated sheets or else by more complex commercially available granulators .
  • the mechanically pre-dewatered sludge 1 is introduced from a storage container 2 via a conveying and granulating device 14 into a fluidized bed 15, which is fluidized by an air flow which is circulated and cooled by the evaporator of a refrigerator.
  • a fluidized bed 15 which is fluidized by an air flow which is circulated and cooled by the evaporator of a refrigerator.
  • the frozen sludge granulate is conveyed into a thawing device 16, which is shown only schematically in FIG. 2 and which also includes the condenser of the refrigerator.
  • Thawing can be carried out like the freezing process in a fluidized bed or, as shown in FIG. 1, in a flowed-through layer lying on a conveyor belt.
  • FIGS. 1 and 2 both have the advantage that frozen sludge on the surface of the device does not have to be removed with special devices such as scrapers or scratches.
  • the method according to the invention can be carried out continuously with both devices, so that the cooling capacity of the refrigerator can be used for freezing and the waste heat of the refrigerator can be used simultaneously for thawing.

Landscapes

  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • 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)
  • Treatment Of Sludge (AREA)

Abstract

Afin que l'aptitude à la déshydratation mécanique de boues de curage soit améliorée, ces dernières sont congelées, puis décongelées. Le processus de congélation altère les parois cellulaires des micro-organismes contenus dans les boues de curage, ce qui facilite l'écoulement de l'eau contenu dans ces cellules lors d'une opération subséquente de déshydratation mécanique des boues de curage décongelées. Ce procédé peut être appliqué en continu, la capacité frigorifique d'une machine frigorifique étant utilisée pour la congélation et la chaleur dégagée servant simultanément à la décongélation. Pour la mise en ÷uvre du procédé, des boues de curage prédéshydratées mécaniquement sont soit congelées dans une couche fluidisée, soit déposées sur une bande transporteuse (3) en vue de leur congélation ou de leur décongélation.
PCT/DE1996/000740 1995-04-29 1996-04-29 Procede et dispositifs permettant d'ameliorer l'aptitude a la deshydratation mecanique de boues de curage Ceased WO1996034833A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU56437/96A AU5643796A (en) 1995-04-29 1996-04-29 Process and device for improving the mechanical dewaterabili ty of sewage sludge

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE1995115862 DE19515862A1 (de) 1995-04-29 1995-04-29 Verfahren und Vorrichtungen zur Verbesserung der mechanischen Entwässerbarkeit von Klärschlamm
DE19515862.8 1995-04-29

Publications (1)

Publication Number Publication Date
WO1996034833A1 true WO1996034833A1 (fr) 1996-11-07

Family

ID=7760732

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1996/000740 Ceased WO1996034833A1 (fr) 1995-04-29 1996-04-29 Procede et dispositifs permettant d'ameliorer l'aptitude a la deshydratation mecanique de boues de curage

Country Status (3)

Country Link
AU (1) AU5643796A (fr)
DE (1) DE19515862A1 (fr)
WO (1) WO1996034833A1 (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5974821A (en) * 1997-05-12 1999-11-02 Scherer; J. Stirling System and method for channeled freeze processing of non-solid materials
DE10245214A1 (de) * 2002-09-27 2004-04-08 Ballies, Uwe, Dr.med. Verfahren zum Entwässern von Faulschlamm
CN114735912A (zh) * 2022-04-12 2022-07-12 南通爱可普环保设备有限公司 一种具有主动通风功能的带式污泥干化机
CN115180794B (zh) * 2022-08-01 2025-01-10 杨红兵 一种活性污泥快速解冻装置及方法
GB202212257D0 (en) * 2022-08-23 2022-10-05 Stow Roger Valentine Drying apparatus and associated drying process

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1182019A (en) * 1967-11-09 1970-02-25 Carves Simon Ltd Improvements in or relating to the dewatering of sludge
DE2151064A1 (de) * 1971-10-13 1973-04-19 Linde Ag Verfahren und vorrichtung zum entfernen der fluessigkeit aus einem gelartigen fluessigkeits-feststoff-gemisch
US3817048A (en) * 1971-07-13 1974-06-18 Water Res Ass Dewatering sludges
GB1459175A (en) * 1972-10-17 1976-12-22 Atomic Energy Authority Uk Treatment of sludges
JPS56155700A (en) * 1980-05-07 1981-12-01 Naomichi Fukushima Method and apparatus for dehydration of excess sludge by freezing

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1182019A (en) * 1967-11-09 1970-02-25 Carves Simon Ltd Improvements in or relating to the dewatering of sludge
US3817048A (en) * 1971-07-13 1974-06-18 Water Res Ass Dewatering sludges
DE2151064A1 (de) * 1971-10-13 1973-04-19 Linde Ag Verfahren und vorrichtung zum entfernen der fluessigkeit aus einem gelartigen fluessigkeits-feststoff-gemisch
GB1459175A (en) * 1972-10-17 1976-12-22 Atomic Energy Authority Uk Treatment of sludges
JPS56155700A (en) * 1980-05-07 1981-12-01 Naomichi Fukushima Method and apparatus for dehydration of excess sludge by freezing

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 006, no. 040 (C - 094) 12 March 1982 (1982-03-12) *

Also Published As

Publication number Publication date
DE19515862A1 (de) 1996-10-31
AU5643796A (en) 1996-11-21

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