GB2312382A - Sludge thickening apparatus - Google Patents

Sludge thickening apparatus Download PDF

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Publication number
GB2312382A
GB2312382A GB9608365A GB9608365A GB2312382A GB 2312382 A GB2312382 A GB 2312382A GB 9608365 A GB9608365 A GB 9608365A GB 9608365 A GB9608365 A GB 9608365A GB 2312382 A GB2312382 A GB 2312382A
Authority
GB
United Kingdom
Prior art keywords
drum
section
sludge
feed
region
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.)
Withdrawn
Application number
GB9608365A
Other versions
GB9608365D0 (en
Inventor
Anthony William Collins
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.)
CPL ENVIRONMENTAL Ltd
ECOLOGICAL PRODUCTS Ltd
Original Assignee
CPL ENVIRONMENTAL Ltd
ECOLOGICAL PRODUCTS Ltd
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 CPL ENVIRONMENTAL Ltd, ECOLOGICAL PRODUCTS Ltd filed Critical CPL ENVIRONMENTAL Ltd
Priority to GB9608365A priority Critical patent/GB2312382A/en
Publication of GB9608365D0 publication Critical patent/GB9608365D0/en
Publication of GB2312382A publication Critical patent/GB2312382A/en
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D37/00—Processes of filtration
    • B01D37/03—Processes of filtration using flocculating agents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D33/00—Filters with filtering elements which move during the filtering operation
    • B01D33/06—Filters with filtering elements which move during the filtering operation with rotary cylindrical filtering surfaces, e.g. hollow drums
    • B01D33/067—Construction of the filtering drums, e.g. mounting or sealing arrangements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D33/00—Filters with filtering elements which move during the filtering operation
    • B01D33/06—Filters with filtering elements which move during the filtering operation with rotary cylindrical filtering surfaces, e.g. hollow drums
    • B01D33/11—Filters with filtering elements which move during the filtering operation with rotary cylindrical filtering surfaces, e.g. hollow drums arranged for outward flow filtration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D33/00—Filters with filtering elements which move during the filtering operation
    • B01D33/35—Filters with filtering elements which move during the filtering operation with multiple filtering elements characterised by their mutual disposition
    • B01D33/37—Filters with filtering elements which move during the filtering operation with multiple filtering elements characterised by their mutual disposition in parallel connection
    • B01D33/39—Filters with filtering elements which move during the filtering operation with multiple filtering elements characterised by their mutual disposition in parallel connection concentrically or coaxially
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D33/00—Filters with filtering elements which move during the filtering operation
    • B01D33/70—Filters with filtering elements which move during the filtering operation having feed or discharge devices
    • B01D33/72—Filters with filtering elements which move during the filtering operation having feed or discharge devices for feeding
    • B01D33/722—Filters with filtering elements which move during the filtering operation having feed or discharge devices for feeding containing fixed liquid displacement elements or cores
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2201/00—Details relating to filtering apparatus
    • B01D2201/18—Filters characterised by the openings or pores
    • B01D2201/188—Multiple filtering elements having filtering areas of different size

Abstract

A sludge thickening apparatus 10 comprises a rotatable drum (12) formed from a wall 16. The wall 16 comprises a first section 28 onto which the sludge can be directed and a second section 30 downstream of the first section. The first section is either solid or defines apertures which are finer i.e. smaller than those defined by the second section. The apparatus 10 further includes feed means 22 i.e. inlet pipe to feed a sludge to be thickened to the drum (12). The inlet pipe 22 includes pumping means (21A), a flocculating tank 32 and flocculant supply means (35) (Fig. 4). The inlet pipe 22 is provided with a bend 24 to enable the sludge to be directed towards the wall 16 at feed region (26), via a feed head (27). The direction of motion of the wall at the feed region is the same as the direction of motion of the sludge at said region (Fig. 2). In an alternative embodiment these motions are in an opposite direction with respect to each other (Fig. 3). The second apertured region 30 is also provided with diverting means in the form of fins 36. The apparatus is used in sewage and other industries which require sludge to be thickened.

Description

ImDrovements in or Relating to Sludge Thickening Apparatus This invention relates to sludge thickening apparatus.
The sewage and other industries require apparatus to thicken sludge.
Present sludge thickening apparatus is not particularly efficient.
According to one aspect of the present invention there is provided sludge thickening apparatus comprising a rotatable drum formed from a wall, and feed means to feed a sludge to be thickened to the inside of the drum, said wall comprising a first section onto which the sludge can be directed from the feed means and a second section downstream of the first section wherein the second section defines a plurality of apertures through which liquid can pass and the first section is either substantially solid or defines apertures which are finer than those defined by the second section.
Preferably, the feed means is arranged to feed the sludge to a feed region on the wall. The direction of motion of the wall at said feed region may be the same direction as, or may be in the opposite direction to, the direction of motion of the sludge at said region.
The second section may be provided with an outlet for thickened sludge.
Preferably at the opposite end of the drum to the feed means.
The feed means may include pumping means to pump the sludge to be thickened to the drum, a flocculating tank between the pumping means and the drum in which the sludge can flocculate and flocculant supply means arranged to supply a flocculant to the feed means via the pumping means.
According to another aspect of the invention there is provided sludge thickening apparatus comprising a rotatable drum formed from a wall defining a plurality of apertures, and feed means to feed a sludge to be thickened to the drum, the feed means including pumping means to pump the sludge to the drum. a flocculating tank between the pumping means and the drum in which the sludge is flocculated, and flocculant supply means arranged to supply a flocculant to the feed means via the pumping means.
The wall may comprise a first section onto which the sludge can be directed from the feed means and a second section downstream of the first section wherein the second section defines a plurality of apertures through which liquid can pass and the first section is either in substantially solid or defines apertures which are finer than those defined by the second section.
According to another aspect of the present invention there is provided sludge thickening apparatus comprising a rotatable drum formed from a wall defining a plurality of apertures, and feed means to feed a sludge to be thickened to the inside of the drum, the feed means being arranged to direct said material against the wall of the drum at a feed region such that when the drum is rotating, the direction of motion of the wall at the feed region is the same as the direction of motion of the sludge at said region.
Preferably, the drum has a first end and a second end, a first section extending inwardly of the drum from the first end, and a second section extending inwardly of the drum from the second end. The feed region is preferably provided at said first section, and the second end may define an outlet for solid material retained in the drum. Preferably the first section is solid or defines apertures which are finer than the apertures defined by the second section. The second apertured region advantageously extends from the second end to the first apertured region.
The first section may extend from the first end to between 15 and 50% of the length of the drum, preferably between 25 and 50%, or preferably substantially 25%.
Preferably, the drum is substantially cylindrical, and is rotatable about the longitudinal axis thereof. The drum is preferably arranged with said axis substantially horizontal.
Preferably, the apertures defined by the first section are 250 microns or less in size, preferably 200 to 250 microns. The apertures in the second section may be 750 microns or less in size, preferably 500 to 750 microns.
The apparatus may further include flocculating means for flocculating the material to be screened prior to being fed to the drum. Preferably, the flocculating means includes a tank to slow the flow of the material therein.
The tank may be provided with baffles. The flocculating means is preferably arranged to provide sufficient residence time therein for the material to flocculate.
The feed means may include pumping means to pump the sludge to the drum. The flocculating tank is preferably arranged between the pumping means and the drum. Flocculant supply means may be provided to supply the flocculant to the feed means via the pumping means.
The second section may be provided with diverting means to cause the solid material retained in the drum towards the second end. Preferably, the diverting means are in the form of fins arranged circumferentially around the drum and a plurality of fins extending from the second end region to the first end region.
An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings, in which: Fig. 1 is a sectional top plan view of the screening apparatus; Fig. 2 is a view along the lines II-II in Fig. 1; Fig 3 is a view along the lines III-III in Fig. 1; and Fig. 4 is a side view of the apparatus shown in Fig. 1.
Referring to the drawings, there is shown sludge thickening apparatus 10 comprising a rotatable substantially cylindrical drum 12 formed from a wall 16 defining a plurality of apertures. The wall 16 may be formed from a mesh, wedgewire, or a sheet of material in which holes are formed by punching, or when the sheet is moulded. The drum 12 defines a first end 18, and a second end 20. An inlet pipe 22 enters the drum 12 via the first end 10 to feed sludge to be thickened to the drum 12. A sludge feed pump 2 1A pumps sludge to be thickened along a feed pipe 21. Thickened sludge retained in the drum, after the liquid has been screened off, exits therefrom via a sludge discharge conduit 23, driven by a sludge transfer pump 23A at the second end 20. The liquid passing through the drum is discharged via a liquid discharge conduit 25.
Referring to Fig. 2 the arrows A represent the direction of rotation of the drum. The inlet pipe 22 is provided with a bend 24 to enable the material to be directed towards the wall 16 at a feed region 26, via a feed head 27. As can be seen, the rotation of the drum 12 is such that the direction of movement of the wall 16 at the feed region 26 is downwardly. This has the effect that sludge directed at the wall 16 is carried by the rotating motion of the drum across substantially 30% of the circumference of the drum, as shown by the double headed arrow B.
The wall 16 defines a first apertured region 28 and a second apertured region 30. The apertured region 28 extends inwardly of the drum 12 substantially 25% of its length, and around the circumference of the drum 12.
The second apertured region 30 extends from the inner edge 29 of the first apertured region 28 to the second end. The apertures defined by the first apertured region are finer than those defined by the second apertured region and, in the embodiment shown, are within the size range of 200 to 250 microns. The size of apertures in the second apertured region 30 are in the size range of 500 to 750 microns. The purpose of this will be explained below.
The apparatus 10 further includes flocculating means in the form of a tank 32 which, if desired, can be provided with baffles 33. The tank 32 is adapted to receive the material to be screened, which has been dosed with a flocculant fed to the material from dosing means 35 via a line 35A to be introduced into the sludge at the feed pump 22A which may be in the form of a polymeric substance, for example, such as that sold under the Trade Mark Z1TAG. The residence time of the material inside the tank 32 has to be sufficient to ensure that a suitable degree of flocculation of the material has occurred.
After exiting the tank 32, the material is fed via the inlet pipe 22 into the drum and is directed at the wall 14 of the drum 12 (See Fig. 2). When the material hits the wall 14, the particles which have been flocculated together to form larger particles are split up into smaller ones. The provision of apertures having sizes in the range of 200 to 250 microns is to prevent solid material which it is intended to be retained in the drum from passing out of the drum at the first apertured region 28. It will be appreciated that the first apertured region could be, if desired, a solid region, i.e. substantially devoid of apertures.
A few seconds after the material has hit the wall 14, the flocculant therein causes the particles which had previously been split up by the impact with the wall 14, to flocculate together again, to produce larger particles. This happens before the material passes to the second apertured region 30 across the edge 29. When the material reaches the second apertured region 30, the particles are large enough to prevent them from passing through the wall 16 and hence are retained in the drum 12. The solid material is then discharged from the drum 12 via the second end, through the solid discharge conduit 23.
Liquid which is passed through the drum 12 is discharged via the liquid discharge conduit 25.
The second apertured region 30 is provided with diverting means in the form of fins 36 which are arranged obliquely on the wall 14. In the embodiment shown, there are three sets of fins 36, each set comprising four fins 36 arranged about the circumference of the drum 12, each fin 36 being arranged at 90 to the adjacent fins 36.
Modifications can be made without departing from the scope of the invention, for example, the drum could rotate in the opposite direction, indicated by the arrows C in Figs. 2 and 3.
Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims (27)

claims
1. Sludge thickening apparatus comprising a rotatable drum formed from a wall, and feed means to feed a sludge to be thickened to the inside of the drum, said wall comprising a first section onto which the sludge can be directed from the feed means and a second section downstream of the first section wherein the second section defines a plurality of apertures through which liquid can pass and the first section is either substantially solid or defines apertures which are finer than those defined by the second section.
2. Apparatus according to claim 1 wherein the feed means is arranged to feed the sludge to a feed region on the wall, the direction of motion of the wall at said feed region being the same direction as, or the direction of motion of the sludge at said region during rotation of the drum.
3. Apparatus according to claim 1 wherein the feed means is arranged to feed the sludge to a feed region on the wall, the direction of motion of the wall at said feed region being the opposite direction to the direction of motion of the sludge at said region during rotation of the drum.
4. Apparatus according to any preceding claim wherein the second section is provided with an outlet for thickened sludge, at the opposite end of the drum to the feed means.
5. Apparatus according to any preceding claim wherein the feed means includes pumpingmeans to pump the sludge to be thickened to the drum, a flocculating tank between the pumping means and the drum in which the sludge can flocculate and flocculant supply means arranged to supply a flocculant to the feed means via the pumping means.
6. Sludge thickening apparatus comprising a rotatable drum formed from a wall defining a plurality of apertures, and feed means to feed a sludge to be thickened to the drum, the feed means including pumping means to pump the sludge to the drum, a flocculating tank between the pumping means and the drum in which the sludge is flocculated, and flocculant supply means arranged to supply a flocculant to the feed means via the pumping means.
7. Apparatus according to claim 6 wherein the wall comprises a first section onto which the sludge can be directed from the feed means and a second section downstream of the first section wherein the second section defines a plurality of apertures through which liquid can pass and the first section is either substantially solid or defines apertures which are finer than those defined by the second section.
8. Sludge thickening apparatus comprising a rotatable drum formed from a wall defining a plurality of apertures, and feed means to feed a sludge to be thickened to the inside of the drum, the feed means being arranged to direct said sludge against the wall of the drum at a feed region such that when the drum is rotating, the direction of motion of the wall at the feed region is the same as the direction of motion of the sludge at said region.
9. Apparatus according to claim 8 wherein the drum has a first end and a second end, a first section extending inwardly of the drum from the first end, and a second section defining a plurality of apertures extending inwardly of the drum from the second end.
10. Apparatus according to claim 9 wherein the feed region is provided at said first section, and the second end defines an outlet for solid material retained in the drum. . -- -
11. Apparatus according to claim 9 or 10 wherein the first section is solid or defines apertures which are firier than the apertures defined by the second section.
12. Apparatus according to claim 9, 10 or 11 wherein the second region extends from the second end to the first region.
13. Apparatus according to any of claims 9 to 12 wherein the first section extends from the first end to between 15 and 50% of the length of the drum.
14. Apparatus according to any of Claims 9 to 13 wherein the first section extends from the first end to between 25 and 50% of the length of the drum.
15. Apparatus according to any of claims 9 to 14 wherein the first section extends from the first end to substantially 25% of the length of the drum.
16. Apparatus according to any of claims 8 to 15 wherein the drum is substantially cylindrical, and is rotatable about the longitudinal axis thereof, the drum being arranged with said axis substantially horizontal.
17. Apparatus according to claim 12 wherein the apertures defined by the first section are 250 microns or less in size.
18. Apparatus according to claim 12 or 17 wherein the apertures defined by the first section are in the region of 200-250 microns in size.
19. Apparatus according to any of claims 9 to 18 wherein the apertures in the second section are 750 microns or less in size.
20. Apparatus according to any of claims 9 to 19 wherein the apertures in the second section are in the region of 500-750 microns in size.
21. Apparatus according to any of claims 8 to 20 further including flocculating means fór flocculating the material to be screened prior to being fed to the drum.
22. Apparatus according to claim 21 wherein the flocculating means includes a tank to slow the flow Df. the material therein. The tank may be provided with baffles, the flocculating means being arranged to provide sufficient residence time therein for the material to flocculate.
23. Apparatus according to claim 21 or 22 wherein the feed means includes pumping means to pump the sludge to the drum, the flocculating tank being arranged between the pumping means and the drum, and flocculant supply means is provided to supply the flocculant to the feed means via the pumping means.
24. Apparatus according to any of claims 8 to 23 wherein the second section is provided with diverting means to cause the solid material retained in the drum towards the second end.
25. Apparatus according to claim 24 wherein the diverting means are in the form of fins arranged circumferentially around the drum and a plurality of fins extending from the second end region to the first end region.
26. Sludge thickening apparatus substantially as herein described with reference to the accompanying drawings.
27. Any novel subject matter or combination including novel subject matter disclosed, whether or not within the scope of or relating to the same invention as any of the preceding claims.
GB9608365A 1996-04-23 1996-04-23 Sludge thickening apparatus Withdrawn GB2312382A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9608365A GB2312382A (en) 1996-04-23 1996-04-23 Sludge thickening apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9608365A GB2312382A (en) 1996-04-23 1996-04-23 Sludge thickening apparatus

Publications (2)

Publication Number Publication Date
GB9608365D0 GB9608365D0 (en) 1996-06-26
GB2312382A true GB2312382A (en) 1997-10-29

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Family Applications (1)

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GB9608365A Withdrawn GB2312382A (en) 1996-04-23 1996-04-23 Sludge thickening apparatus

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1289708A (en) * 1969-04-24 1972-09-20
GB1569475A (en) * 1976-03-27 1980-06-18 Kopalnia Wegla Kamiennego Bole Apparatus for continuous dewatering in the process of hydromechanical and mechanical treatmentof flocculated sludges
US4306975A (en) * 1979-05-21 1981-12-22 Escher Wyss Gmbh Sieve apparatus containing a rotatable circular sieve

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1289708A (en) * 1969-04-24 1972-09-20
GB1569475A (en) * 1976-03-27 1980-06-18 Kopalnia Wegla Kamiennego Bole Apparatus for continuous dewatering in the process of hydromechanical and mechanical treatmentof flocculated sludges
US4306975A (en) * 1979-05-21 1981-12-22 Escher Wyss Gmbh Sieve apparatus containing a rotatable circular sieve

Also Published As

Publication number Publication date
GB9608365D0 (en) 1996-06-26

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Legal Events

Date Code Title Description
730 Substitution of applicants allowed (sect. 30/1977)
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)