CLAIMS
1. A method for separation of waste material containing a solid fraction and a liquid fraction, said method comprising the steps of: - passing the waste material to a first chamber, vibrating said first chamber having an open bottom, said open bottom comprising a porous generally horizontal screen having pores of a size sufficiently small for larger-sized solid particles of the waste material not passing through the screen but being retained in the first chamber,
- subsequent to the waste material having passed the first chamber, passing a remaining part of the waste material through the first generally horizontal porous screen and into at least one second chamber, vibrating said at least one second chamber having an open bottom, said open bottom comprising a second generally horizontal porous screen having pores of a size sufficiently small for smaller-sized solid particles of the waste material not passing through the screen but being retained in the at least one second chamber, and - subsequent to the waste material having passed the first chamber and the remaining part of the waste material having passed the first generally horizontal porous screen, and subsequent to the remaining part of the waste material having passed the at least one second chamber, passing an even remaining part of the waste material through the second generally horizontal porous screen and into a third chamber having a closed bottom for collecting in the third chamber a resulting liquid fraction of the waste material and possibly being discharged from the third chamber.
2. A method according to claim 1, said method comprising the steps of:
- , subsequent to the waste material having passed the first chamber and having passed the first generally horizontal porous screen, passing the remaining part of the waste material into a sequential plurality of second chambers,
- each of said plurality of second chambers having an open bottom comprising a porous generally horizontal screen having pores of a size sufficiently small for solid particles of the waste material not passing through the screen but being retained in the second chambers, and
- where the sequential plurality of second chambers each is provided with a generally horizontal porous screen, said generally horizontal porous screens having sequentially diminishing mesh-size along the sequential plurality of second chambers.
3. A method according to claim 1 or claim 2, said method further comprising the step of:
- removing from the first chamber larger-sized solid particles of the waste material by accumulating said larger-sized solid particles along a circumference of the first chamber, preferably along a substantially circular circumference of the first chamber, alternatively along an oval circumference of the first chamber, even in the alternative along a polygonal circumference of the first chamber, and providing said circumference of the first chamber with at least one tangentially extending outlet.
4. A method according to any of the preceding claims, said method further comprising the step of:
- removing from the at least one second chamber smaller-sized solid particles of the waste material by accumulating said smaller-sized solid particles along a circumference of the second chamber, preferably along a substantially circular circumference of the second chamber, alternatively along an oval circumference of the second chamber, even in the alternative along a polygonal circumference of the third chamber, and providing said circumference of the second chamber with at least one tangentially extending outlet.
5. A method according to any of the preceding claims, said method further comprising the step of: - removing from the third chamber a liquid fraction of the waste material by accumulating said liquid along a circumference of the third chamber, preferably a substantially circular circumference of the third chamber, alternatively an oval circumference of the third chamber, even in the alternative a polygonal circumference of the third chamber, and providing said circumference of the third chamber with at least one tangentially extending outlet, alternatively providing said circumference of the third chamber with at least one radially extending outlets, even in the alternative providing said circumference of the third chamber with at least one downwards extending outlet being provided in the closed bottom of the third chamber.
6. A method according to any of the preceding claims, said method further comprising the step of:
- removing from the third chamber a liquid fraction of the waste material by accumulating said liquid along a substantially circular circumference of the third chamber, alternatively an oval circumference of the third chamber, and providing said circumference of the third chamber with at least one radially extending outlet.
7. A method according to any of the preceding claims, said method further comprising the step of:
- removing from the third chamber a liquid fraction of the waste material by accumulating said liquid along a substantially circular circumference of the third chamber, alternatively an oval circumference of the third chamber, and providing said circumference of the third chamber with at least one downwards extending outlet being provided in the closed bottom of the third chamber.
8. A method according to any of the preceding claims, said method comprising the step of
- adding an acidifying component to the waste material, before the waste material is passed to the first chamber, alternatively when the waste material is passed to the first chamber.
5
9. A method according to any of the preceding claims, said method comprising the step of
- adding an oxidizing agent to the waste material, before the waste material is passed to the first chamber, alternatively when the waste material is passed to the first chamber.
10 10. A method according to any of the preceding claims, said method comprising the step of
- adding an acidifying component to the remaining waste material, subsequent to having passed the first chamber, and subsequent to having passed the first porous screen.
11. A method according to any of the preceding claims, said method comprising the step of 15 - adding an oxidizing agent component to the remaining waste material, subsequent to having passed the first chamber, and subsequent to having passed the first porous screen.
12. A method according to any of the preceding claims, said method comprising the step of
- adding an acidifying component to the remaining waste material, subsequent to the 20 waste material having passed at least one of the at least one second chambers, and subsequent to the waste material having passed at least one of the at least one second porous screens.
13. A method according to any of the preceding claims, said method comprising the step of 25 - adding an oxidizing agent to the remaining waste material, subsequent to the waste material having passed at least one of the at least one second chambers, and subsequent to the waste material having passed at least one of the at least one second porous screens.
30 14. A method according to any of the preceding claims, where the waste material containing a solid fraction and a liquid fraction is collected from manure of livestock.
15. A method according to any of the preceding claims, where the waste material containing a solid fraction and a liquid fraction is collected from organic waste water or
35 sludge.
16. An apparatus for separation of waste material comprising a solid fraction and a liquid fraction, said apparatus comprising: a base, resilient means connecting said base to a plurality of chambers, vibratory means coupled with said plurality of chambers, said plurality of chambers comprising
- a first chamber having at least one first screen having a larger-sized mesh being provided at a lower part of the first chamber and said first chamber having a tangentially extending outlet, and said plurality of chambers furthermore comprising - a second chamber having at least one second screen having a smaller-sized mesh being provided at a lower part of the second chamber and said second chamber having a tangentially extending outlet, and said plurality of chambers furthermore comprising
- a third chamber having a closed lower part, preferably being provided with an outlet, so that a resulting liquid fraction of the waste material is capable of being collected in the third chamber, and subsequently preferably being capable of being let out of the third chamber.
17. A method for separation of waste material comprising a solid fraction and a liquid fraction, said method comprising the steps of: - passing the waste material to a first chamber, and adding an acidifying component to the waste material, before the waste material is passed to the first chamber or when the waste material is passed to the first chamber,
- vibrating said first chamber having an open bottom comprising a porous screen having pores of a size sufficiently small so that larger-sized solid particles of the waste material cannot pass there-through but is retained in the first chamber, and
- passing a remaining part of the waste material through the first porous screen, and
- passing the remaining part of the waste material, subsequent to the waste material having passed the first chamber and having passed the first porous screen, into a subsequent chamber having a closed lower part, preferably being provided with an outlet, so that a resulting liquid fraction of the waste material is capable of being collected in the third chamber, and subsequently preferably being capable of being let out of the third chamber.
18. A method according to claim 17, said method comprising the further step of - passing a remaining part of the waste material, subsequent to the waste material having passed the first chamber and having passed the first porous screen, into at least one second chamber, vibrating said at least one second chamber having an open bottom comprising a second porous screen having pores of a size sufficiently small so that smaller- sized solid particles of the waste material cannot pass there-through but is retained in the second chamber,
19. A method according to claim 17 or claim 18, said method comprising the step of adding an acidifying component to the remaining waste material, subsequent to the waste material having passed the first chamber, and subsequent to the waste material having passed the first porous screen.
20. A method for separation of waste material comprising a solid fraction and a liquid 5 fraction, said method comprising the steps of:
- passing the waste material to a first chamber, and adding an oxidizing agent to the waste material, before the waste material is passed to the first chamber or when the waste material is passed to the first chamber,
- vibrating said first chamber having an open bottom comprising a porous screen having 10 pores of a size sufficiently small so that larger-sized solid particles of the waste material cannot pass there-through but is retained in the first chamber, and
- passing a remaining part of the waste material through the first porous screen, and
- passing the remaining part of the waste material, subsequent to the waste material having passed the first chamber and having passed the first porous screen, into a
15 subsequent chamber having a closed lower part, preferably being provided with an outlet, so that a resulting liquid fraction of the waste material is capable of being collected in the third chamber, and subsequently preferably being capable of being let out of the third chamber.
20 21. A method according to claim 20, said method comprising the further step of
- passing a remaining part of the waste material, subsequent to the waste material having passed the first chamber and having passed the first porous screen, into at least one second chamber, vibrating said at least one second chamber having an open bottom comprising a second porous screen having pores of a size sufficiently small so that smaller-
25 sized solid particles of the waste material cannot pass there-through but is retained in the second chamber,
22. A method according to claim 20 or claim 21, said method comprising the step of adding an oxidizing agent to the remaining waste material, subsequent to the waste
30 material having passed the first chamber, and subsequent to the waste material having passed the first porous screen.
23. An apparatus for separation of waste material comprising a solid fraction and a liquid fraction, said apparatus comprising: a base, resilient means connecting said base to a
35 plurality of chambers, vibratory means coupled with said plurality of chambers, said plurality of chambers at least comprising
- a first chamber having at least one first screen having a larger-sized mesh being provided at a lower part of the first chamber and said first chamber having a tangentially extending outlet, and said plurality of chambers furthermore comprising - at least one second chamber having a second screen having a smaller-sized mesh being provided at a lower part of the second chamber and said second chamber having a tangentially extending outlet, and said plurality of chambers furthermore comprising
- said first chamber having means for adding an acidifying component to the waste material, before the waste material is passed to the first chamber or when the waste material is passed to the first chamber.
24. An apparatus for separation of waste material comprising a solid fraction and a liquid fraction, said apparatus comprising: a base, resilient means connecting said base to a plurality of chambers, vibratory means coupled with said plurality of chambers, said plurality of chambers at least comprising
- a first chamber having at least one first screen having a larger-sized mesh being provided at a lower part of the first chamber and said first chamber having a tangentially extending outlet, and said plurality of chambers furthermore comprising - at least one second chamber having a second screen having a smaller-sized mesh being provided at a lower part of the second chamber and said second chamber having a tangentially extending outlet, and said plurality of chambers furthermore comprising
- said first chamber having means for adding an oxidizing agent component to the waste material, before the waste material is passed to the first chamber or when the waste material is passed to the first chamber.
25. An apparatus for separation of waste material comprising a solid fraction and a liquid fraction, said separator comprising:
- a first separation means having a first base and a resilient means connecting said first base to a plurality of chambers, and vibratory means coupled with said plurality of chambers, thereby being capable of exerting a vibratory motion to waste material in the first separation means, and
- a second separation means having a second base and a pressurising means being displaceable in relation to said second base, and actuation means coupled to said pressurising means, thereby being capable of exerting a pressure to waste material in the second separation means, and
- said pressurising means being in waste material-handling connection with said vibratory means so that waste material is capable of passing from the first separation means to the second separation means, alternatively from the second separation means to the first separation means.
26. An apparatus according to claim 25, said pressurising means comprising
- a helical displacement means and a pipe in which the helical displacement means is capable of rotating for displacing waste material from an inlet of the pipe to an outlet of the pipe, - said helical displacement means having a pitch gradually tapering from the inlet of the pipe to the outlet of the pipe, said tapering resulting in a pressurising of the waste material.
27. An apparatus according to claim 25, said pressurising means comprising - a helical displacement means and a pipe in which the helical displacement means is capable of rotating for displacing waste material from an inlet of the pipe to an outlet of the pipe,
- said helical displacement means having a decreasing diameter from the inlet of the pipe to the outlet of the pipe, said decreasing diameter resulting in a pressurising of the waste material.
28. An apparatus according to claim 25, said pressurising means comprising
- a helical displacement means and a pipe in which the helical displacement means is capable of rotating for displacing waste material from an inlet of the pipe to an outlet of the pipe,
- said helical displacement means having a substantially equal diameter from the inlet of the pipe to the outlet of the pipe and having an end baffle, said end baffle resulting in a pressurising of the waste material. |
METHOD FOR SEPARATION OF WASTE MATERIAL AND APPARATUS FOR SUCH METHOD
FIELD OF THE INVENTION
The invention relates to a method for separation of waste material such as manure from livestock, e.g. horses, cattle, sheep, pigs, mink, foxes and other useful animals kept or raised on a farm or a ranch, or waste material such as organic waste water and slurry, said waste material comprising a solid fraction and a liquid fraction. The solid fraction and the liquid fraction is often collected from manure gutters of livestock stables or sheds or is collected from organic waste water basins or other vessels, and the solid fraction and the liquid fraction is passed to separation plants for separation of at least part of the solid fraction from the liquid fraction. The invention also relates to an apparatus for such method, said apparatus comprising a vibratory separation apparatus.
BACKGROUND OF THE INVENTION
Vibratory separation apparatuses are known for separation of a solid fraction from a liquid fraction of manure. Many such vibratory apparatuses make use of a sloping screen, where the manure is passed along the screen, and where the liquid fraction passes through the mesh of the screen, when the manure is passing along the screen from an inlet of the screen to an outlet of the screen. The solid fraction having a size larger than the mesh-size of the screen is retained on top of the screen and is passed to an outlet of the screen.
Vibratory separation apparatuses are also known making use of a horizontal screen combined with the vibratory motion for separation of the liquid fraction from the solid fraction. The vibratory motion is applied so that a solid fraction having a size larger than the mesh-size of the screen is retained on top of the screen and is diverted towards the side of the screen, and the liquid fraction is passed through the mesh of the screen.
However, disadvantages occur in known vibratory separation apparatuses.
The amount of manure having to be separated may be exorbitant compared to the capacity of a vibratory separation apparatus. Vibratory separation apparatuses rely on gravity in combination with the vibratory motion when separating manure. Either the vibratory motion must have a high frequency and/or the surface area of the screen must be high in order of obtaining a sufficient and at the same time satisfactory separation.
Also, due to different fatty substances in the manure, the screen of the vibratory separation apparatus tends to clog. Repeated cleaning of the screen is thus necessary in
order of maintaining a certain separation capacity of the vibratory apparatus. Alternatively, the mesh-size of the screen may be increased so that the screen will not clog.
US 3,918,404 discloses a process for inhibiting the generation of ammonia through the control of the pH in animal excreta under the slotted floors of animal enclosures and for the reduction of odours and noxious gases through the utilization of ozone as an oxidizing agent for the destruction of bacteria associated with the production of hydrogen sulphide and other objectionable products of waste decomposition. One step of the process disclosed includes a resulting mixture being deposited on a vibrating screening apparatus which separates fibrous matter from liquids. The liquids may be combined with additional chemicals including varying amounts of polymer, gypsum and ammonia as appropriate to further promote the separation of solids and liquids. No other details relating to the vibrating screen, i.e. the separation process or the separation apparatus, are disclosed.
Furthermore, the size of the solid particles to be retained, and the amount of remaining solid particles in the liquid fraction, may be dependent on the final usage and disposal of the solid fraction and the liquid fraction. It may not be possible to fulfil one criteria of a certain size or a certain dry matter content of the solid fraction at the same time as fulfilling other criteria of a certain small size of solid particles or a certain low amount of dry matter in the liquid fraction.
SUMMARY OF THE INVENTION
It may be an the object being able to increase the total amount of waste material being separated by means of only a certain limited number of vibratory separation apparatuses.
It may be another object to increase the total amount of waste material being separated by means of an increased time of operation of a number of vibratory separation apparatus.
Furthermore, it may be an object to obtain a separation where the fractions of the waste material are better suited for subsequent use and/or disposal.
These objects may be obtained by a method comprising the steps of:
- passing the waste material to a first chamber, vibrating said first chamber having an open bottom, said open bottom comprising a porous generally horizontal screen having pores of a size sufficiently small for larger-sized solid particles of the waste material not passing through the screen but being retained in the first chamber,
- subsequent to the waste material having passed the first chamber, passing a remaining part of the waste material through the first generally horizontal porous screen and into at least one second chamber, vibrating said at least one second chamber having an open bottom, said open bottom comprising a second generally horizontal porous screen having
pores of a size sufficiently small for smaller-sized solid particles of the manure not passing through the screen but being retained in the at least one second chamber,
- subsequent to the waste material having passed the first chamber and the remaining part of the waste material having passed the first generally horizontal porous screen, and subsequent to the remaining part of the waste material having passed the at least one second chamber, passing an even remaining part of the manure through the second generally horizontal porous screen and into a third chamber having a closed bottom for a resulting liquid fraction of the waste material being collected in the third chamber and possibly being discharged from the third chamber.
Passing the waste material such as livestock manure through at least two screens having different mesh-size, the first screen having the largest mesh-size and the second screen having the smaller mesh-size, provides the advantage of separating a larger amount of waste material because at least three outlets are provided, namely the outlet of the larger- sized solid particles of the solid fraction, the outlet of the smaller-sized solid particles of the solid fraction and the outlet of the liquid fraction.
Passing the waste material such as livestock manure through at least two screens having different mesh-size, the first screen having the largest mesh-size and the second screen having the smaller mesh-size, also provides the advantage of separating the solid fraction into at least two fractions, a first fraction consisting only of larger-sized solid particles and a second fraction consisting only of smaller sized solid particles. Thus, the different fractions of the solid fraction may be 'designed' for a certain subsequent use and/or a certain subsequent disposal.
In a possible aspect of the method, the method comprises the steps of
- passing the remaining part of the waste material, subsequent to having passed the first chamber and having passed the first generally horizontal porous screen, into a sequential plurality of second chambers,
- where the sequential plurality of second chambers each is provided with at least one generally horizontal porous screen, said generally horizontal porous screens having sequentially diminishing pores along the sequential plurality of second chambers
- retaining solid parts of the waste material from one second chamber to another second chamber along the sequence of chambers, when the at least one porous generally horizontal screen of the one second chamber is having pores of a size sufficiently small for at least some of the solid parts of the waste material not passing there-through.
By passing some of the solid parts of the waste material through the screen of one second chamber and by retaining other of the solid parts, a sequential separation of the solid parts is provided. Thus, the different fractions of the solid fraction may be 'designed' for a
certain subsequent use and/or a certain subsequent disposal. Also, the total amount of waste material capable of separation by means of the vibratory separation apparatuses is increased because not all the solid parts have to be retained by only one screen.
According to preferred methods steps according to the invention, the method further comprises at least one of the following steps of:
- removing from the first chamber larger-sized solid particles of the waste material by accumulating said larger-sized solid particles along a circumference of the first chamber, preferably along a substantially circular circumference of the first chamber, alternatively along an oval circumference of the first chamber, even in the alternative along a polygonal circumference of the first chamber, and providing said circumference of the first chamber with at least one tangentially extending outlet, or
- removing from the at least one second chamber smaller-sized solid particles of the waste material by accumulating said smaller-sized solid particles along a circumference of the second chamber, preferably along a substantially circular circumference of the second chamber, alternatively along an oval circumference of the second chamber, even in the alternative along a polygonal circumference of the second chamber, and providing said circumference of the second chamber with at least one tangentially extending outlet, or
- removing from the third chamber a liquid fraction of the waste material by accumulating said liquid along a circumference of the third chamber, preferably along a substantially circular circumference of the third chamber, alternatively along an oval circumference of the third chamber, even in the alternative along a polygonal circumference of the third chamber, and providing said circumference of the third chamber with at least one tangentially extending outlet, alternatively providing said circumference of the third chamber with at least one radially extending outlets, even in the alternative providing said circumference of the third chamber with at least one downwards extending outlet being provided in the closed bottom of the third chamber, or
- removing from the third chamber a liquid fraction of the waste material by accumulating said liquid along a substantially circular circumference of the third chamber, alternatively an oval circumference of the third chamber, and providing said circumference of the third chamber with at least one radially extending outlet, or even
- removing from the third chamber a liquid fraction of the waste material by accumulating said liquid along a substantially circular circumference of the third chamber, alternatively an oval circumference of the third chamber, and providing said circumference of the third
chamber with at least one downwards extending outlet being provided in the closed bottom of the third chamber.
The removing of the smaller-sized and the larger-sized particles of the solid fraction and/or the liquid fraction by any one or more of the above method steps results in an easy but still satisfactory removal of the solid fraction and/or the liquid fraction. Also, an improvement in the possibility of maintaining the screens free from any clogging of the screens because of formation of precipitates from magnesium, from ammonium and/or from phosphate on the screens or in the mesh of the screens of the first chambers and of the possible one or more second chambers. Thus, not only the solid and/or liquid fraction is removed from the screen, but perpetuated efficiency of the method is obtained.
The waste material being separated by the method according to the method may be collected from different sources. Thus the waste material may be collected from livestock manure, i.e. manure and other faeces from horses, cattle, sheep, pigs, mink, foxes and other useful animals kept and bred at farms, ranches or the like locations, as example also zoos and other such locations, where the usefulness of the animals is different, i.e. useful from an idealistic and educational view, than the usefulness at ranches, farms etc.
The waste material may also be collected from organic waste waster, sewage sludge and the like droppings form animals, either collected at site where the waste material is produced or is generated, e.g. at small households or at industry plants, or collected from other collective sites, i.e. sites for treating the organic waste water, the sewage or the sludge.
Further means for maintaining the screens free from any clogging of the screens because of formation of precipitates from magnesium, from ammonium and/or from phosphate on the screens or in the mesh of the screens of the first chambers and of the possible one or more second chambers may be effected by the method comprising the step of: - adding an acidifying component and/or an oxidizing agent to the waste material, before the waste material is passed to the first chamber, alternatively when the waste material is passed to the first chamber, and/or
- adding an acidifying component and/or an oxidizing agent to the remaining waste material, subsequent to having passed the first chamber, and subsequent to having passed the first porous screen, and/or
- adding an acidifying component and/or an oxidizing agent to the remaining waste material, subsequent to the waste material having passed at least one of the at least one second chambers, and subsequent to the waste material having passed at least one of the at least one second porous screens.
The objects may also be obtained by a method comprising the steps of:
- passing the waste material to a first chamber, and adding an acidifying component and/or an oxidizing agent to the waste material, before the waste material is passed to the first chamber or when the waste material is passed to the first chamber,
- vibrating said first chamber having an open bottom comprising a porous screen having pores of a size sufficiently small so that larger-sized solid particles of the waste material cannot pass there-through but is retained in the first chamber, and
- passing a remaining part of the waste material through the first porous screen, and - passing the remaining part of the waste material, subsequent to the waste material having passed the first chamber and having passed the first porous screen, into a subsequent chamber having a closed lower part, preferably being provided with an outlet, so that a resulting liquid fraction of the waste material is capable of being collected in the third chamber, and subsequently preferably being capable of being let out of the third chamber.
Precipitates from magnesium, from ammonium and/or from phosphate may form on the screens or in the mesh of the screens of the first chambers and of the possible one or more second chambers. Formation of precipitates causes eventual clogging of the screens.
Adding an acidifying component to the waste material at any one or more step during separation provides the advantage of limiting any clogging of the one or more screens, which the waste material is passed through. The acidifying component may be an acid itself such as H 2 SO 4 , HCI, HNO 3 , H 3 PO 4 or other acids themselves, but the acidifying component may also be an acid-containing component such as Fe 2 (SO 4 ) 3 , AI 2 (SO 4 ) 3 or any other acid salt, or may even be a component developing acid when added to the waste material.
Adding an oxidizing agent to the waste material at any one or more step during separation provides the advantage of limiting any clogging of the one or more screens, which the waste material is passed through. The oxidizing agent may be oxygen itself such, but the oxidizing agent may also be an oxygen-containing component such as atmospheric air.
The objects of the invention may even be obtained by an apparatus comprising: - a first separation means having a first base and a resilient means connecting said first base to a plurality of chambers, and vibratory means coupled with said plurality of chambers, thereby being capable of exerting a vibratory motion to waste material in the first separation means, and
- a second separation means having a second base and a pressurising means being
displaceable in relation to said second base, and actuation means coupled to said pressurising means, thereby being capable of exerting a pressure to waste material in the second separation means, and
- said pressurising means being in waste material-handling connection with said vibratory means so that waste material is capable of passing from the first separation means to the second separation means, alternatively from the second separation means to the first separation means.
An apparatus in itself comprising two different types of separation principles is contradictory. One type of separation principle will always be preferred above other principles. The type of separation principle chosen depends on the material to be separated, on the final constituents of the separated material and on costs of purchasing the separation apparatus and the costs of operating the separation apparatus. Using two types of separation principles necessitating two different apparatuses will increase both the costs of purchase and the costs of operation. Thus, the obvious choice for the person skilled in the art will be to purchase only one apparatus, but perhaps purchasing and operating an apparatus having a larger capacity, when increased separation capacity is needed.
The means for pressurising the waste material is preferably a helical screw, most preferred as adopted in a so-called screw press, where the helical screw is rotating in a pipe, preferably a perforated pipe, so that during pressurising of the waste material, at least a major part of the liquid fraction is passed from the waste material in the pipe and through the perforations in the pipe to an outlet for the liquid fraction. The solid fraction is retained in the screw press and is removed form the screw press by any suitable means such as by scraping the solid fraction from an end section of the pipe.
The helical displacement means, i.e. in a screw press the screw itself, may perform the pressurising by any suitable mechanical adoption of the helical screw, but three major solutions are the following, each being easily applicable and each solution having advantages, which may be beneficial when separating waste material. The solutions are:
- said helical displacement means having a pitch gradually tapering from the inlet of the pipe to the outlet of the pipe, said tapering resulting in a pressurising of the waste material, or - said helical displacement means having a decreasing diameter from the inlet of the pipe to the outlet of the pipe, said decreasing diameter resulting in a pressurising of the waste material, or
- said helical displacement means having a substantially equal diameter from the inlet of the pipe to the outlet of the pipe and having an end baffle, said end baffle resulting in a
pressurising of the waste material.
Either way of performing a pressurising of the waste material may be equally suitable; however, the preferred solution is the latter, i.e. providing an end baffle. At the end baffle, the solid matter having been displaced to the very end of the perforated pipe may be scraped off the helical displacement means. The helical displacement means is a mechanically safe and simple solution for separating dry matter form liquid matter. However, in itself the separation has a limited capacity and a continuous removal from the helical displacement means of dry matter is necessary for maintaining a sufficient capacity.
Results from use of the apparatus according to the invention demonstrate a very high separation capacity compared to separation capacities of prior art apparatuses. The very high separation capacity is mainly due to the at least two steps of separation of the solid particles. At least two steps of separation of the solid particles increase the separation capacity, however, without the use of two apparatuses. Also, the use of at least two separation steps renders the possibility of tuning the mesh size of each of the separation steps in respect of the texture, the content and the flow rate of the waste material, and still by only using one apparatus for performing an optimum separation by vibration.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following, the invention will be described with reference to the drawings, where
Fig. 1 is a schematic drawing of a first embodiment of a separator according to the invention and comprising a vibratory separation apparatus with a plurality of screens, and Fig. 2 is a schematic drawing of a second embodiment of a separator according to the invention and comprising a vibratory separation apparatus combined with a screw press, and where the screw press is situated before the vibratory apparatus.
DETAILED DESCRIPTION OF THE INVENTION
Fig. 1 shows schematically a first embodiment of a vibratory separation apparatus for separation of waste material. The waste material may be livestock manure or it may be organic wastewater from households or from certain industries, or it may be sludge. In the following, livestock manure will be used as an example of waste material capable of being separated by the method and apparatus according to the invention. However, the use of livestock manure as example of waste material is not to be construed as a limitation to separating other waste material comprising a solid fraction and a liquid fraction.
The first embodiment of the vibratory separation apparatus comprises a first chamber 1 being provided with an open bottom part 4 constituted by a first screen 5, a second chamber 2 also comprising an open bottom part 6 constituted by a second screen 7 and a third chamber 3 comprising a closed bottom 8.
Manure M comprising both a solid fraction and a liquid fraction is intended for being applied to the first chamber 1. The first screen 5 is having a mesh-size being larger than the mesh-size of the second screen 7. Optionally, more than one second chamber may be provided in sequence between the first chamber 1 and the third chamber 3. The mesh-size of a sequentially initial second screen (not shown) will thus be larger than the mesh-size of a sequentially subsequent second screen (not shown).
The first chamber 1, the second chamber 2 and the third chamber 3 are all supported by a base 10, and resilient means 11 such as helical springs are connecting said base 10 to the plurality of chambers 1, 2, 3. In an alternative embodiment, only the first chamber 1 and the second chamber 2, i.e. the chambers having bottoms 4,6 constituted by screens 5,7, are supported by the base 10 and the resilient means 11 such as helical springs are connecting said base 10 to only the first chamber 1 and the second chamber 2.
Vibratory means 12 such as an electric motor being fixed to the base 10 and having the rotary axle 13 of the motor 12 coupled eccentrically with the plurality of chambers 1, 2, 3, or at least to the first chamber 1 and the second chamber 2. The vibratory means 12 are intended for vibrating the plurality of chambers 1, 2, 3, or at least the first chamber 1 and the second chamber 2, in an upward and downward motion, but preferably also in a sideway rotary motion.
The upward and downward motion results in the fractions of the manure not being retained in the first chamber more easily passing to the second chamber, and in the fractions of the manure not being retained in the second chamber more easily passing to the third chamber.
The sideway motion results in a larger-sized fraction 14 of the manure being retained in the first chamber 1, a smaller-sized fraction 15 being retained in the second chamber 2 and at least a liquid fraction 16 being retained in the third chamber, respectively, being led to chamber side walls 17, 18, 19 constituting lateral boundaries of the chambers 1, 2, 3, respectively.
The rotary motion results in the fractions 14, 15, 16 of the manure being retained in the first chamber 1, in the second chamber 2 and in the third chamber 3, respectively, being
led circumferentially along the chamber side walls 17, 18, 19, respectively, towards possible outlets 21, 22, 23 provided in the chamber side walls 17, 18, 19.
The larger-sized solid particles 14 of the solid fraction being larger than the mesh-size of the first screen 5 are retained in the first chamber 1. The remaining part of the manure, i.e. the liquid fraction 16 and the smaller-sized particles 15 of the solid fraction, passes through the first screen 5 and into the second chamber 2. The smaller-sized particles 15 of the solid fraction being larger than the mesh-size of the second screen 7 are retained in the second chamber 2. The remaining part of the manure, i.e. the liquid fraction 16 and possibly even smaller-sized particles (not shown) of the solid fraction, passes through the second screen 7 and into the third chamber 3. The liquid fraction 16 and the possible even smaller-sized particles (not shown) of the solid fraction are retained in the third chamber 3.
Preferably, as shown, the first chamber 1, the second chamber 2 and the third chamber 3 are each provided with outlets 21, 22, 23 for letting out the fractions 14, 15, 16 of the manure, which are retained in the chamber in question. Thus, the first chamber 1 is provided with a first outlet 21 for letting out the larger-sized particles 14 of the solid fraction, the second chamber 2 is provided with a second outlet 22 for letting out the smaller-sized particles 15 of the solid fraction, and the third chamber 3 is provided with a third outlet 23 for letting out the liquid fraction 16 and the possible even smaller-sized particles (not shown) of the solid fraction.
The outlets 21, 23, 24 may be provided in any suitable manner, but preferably the outlets are provided tangentially to the circumference of the chambers. However, in alternative embodiment, the outlets may be provided radially to the circumference of the chambers, and the third outlet may even be provided axially, either in the centre of bottom of the third chamber or off-set in relation to the centre of the bottom of the third chamber.
The mesh-size of the first screen 5 and the mesh-size of the second screen 7 may vary depending on the livestock, which the manure originates form, and depending on the demand or desire for separation, i.e. how large the larger-sized particles 14 of the solid fraction has to be or is intended to be, and how small the smaller-sized particles 15 of the solid fraction has to be or is intended to be. Preferred mesh-sizes of the first screen 5 are between 50 μm and 500 μm, and preferred mesh-sizes of the second screen 7 are between 10 μm and 250 μm. However, the mesh-sizes are dependent on which waste material is separated, and the mesh-sizes are also dependent on the size of the fraction, which is needed or wanted in the separation step in question.
Fig. 2 shows schematically a second embodiment of a vibratory separation apparatus for separation of livestock manure. The second embodiment of the vibratory separation apparatus comprises a vibratory apparatus and a helical displacement means 24 and a perforated pipe 25 in which the helical displacement means 24 is capable of rotating for displacing manure from an inlet 26 of the pipe 25 to an outlet 27 of a collection vessel 28 situated beneath the helical displacement means 24 and the perforated pipe 25, i.e. such as a screw press as shown. The screw press will be used hereafter as an example of an apparatus having a helical displacement means 24. The vibratory apparatus and the screw press are mutually coupled (not shown) so that manure is capable of passing from screw press to the vibratory separation apparatus, as shown by the arrow A, alternatively or additionally from the vibratory separation apparatus to the screw press.
The pressurising of the manure M may be applied by different means incorporated into the screw press. The helical displacement means 24, i.e. the screw, may have a pitch P gradually tapering from the inlet 26 of the pipe 25 to a distant end 29 of the pipe 25, said tapering resulting in a pressurising of the manure. Alternatively, the helical displacement means 24, i.e. the screw, may have a decreasing diameter D from the inlet 26 of the pipe 25 to the distant end 29 of the pipe 25, said decreasing diameter resulting in a pressurising of the manure. Or, as shown, the helical displacement means 24, i.e. the screw, may have a substantially equal diameter D from the inlet of the pipe to the outlet of the pipe, and may have a substantially equal pitch P from the inlet 26 of the pipe 25 to the distant end 29 of the pipe, and the pipe is in stead provided with an end baffle 30, said end baffle 30 resulting in a pressurising of the manure. Even in the alternative, one or more of the above-mentioned different configurations and designs of the helical displacement means 24 and of the pipe 25 may be combined in any suitable manner.
The screw press is preferably intended for a preliminary treatment of the solid fraction and liquid fraction containing manure in order decrease the dry matter of the manure being led to the vibratory separation apparatus. Alternatively, the screw press is intended for a subsequent treatment of a solid fraction of the manure from the vibratory separation apparatus, in order to further increase the dry matter content of the solid fraction from the vibratory separation apparatus. Accordingly, the combination of a screw press and a vibratory separation apparatus, independent on whether the screw press is employed preliminary to the vibration separation apparatus or is employed subsequent to the vibration separation apparatus, increases the effect of separating of the manure in the solid fraction and the liquid fraction.
The vibratory separation apparatus comprises at least one first chamber 1 being provided with an open bottom part 4 constituted by a first screen 5. Optionally, but not necessarily,
the vibratory separation apparatus also comprises a sequence of one or more second chambers (not shown, see fig. 1) also comprising an open bottom part and constituted by a second screen. The vibratory separation apparatus also comprises a third chamber 3 comprising a closed bottom 8.
Manure M comprising both a solid fraction and a liquid fraction is intended for being applied to the first chamber. The first chamber 1, and the optional one or more second chambers, and the third chamber 3 are all supported by a base 10, and resilient means 11 such as helical springs are connecting said base 10 to the plurality of chambers 1, 2. In an alternative embodiment, only the first chamber 1 and the optional one or more second chambers, i.e. the chambers having bottoms constituted by screens, are supported by the base 10 and the resilient means 11 such as helical springs are connecting said base 10 to only the first chamber 1 and the possible one or more second chambers.
Vibratory means such as an electric motor 12 or any other kind of motor suitable for the purpose such as a hydraulic motor being fixed to the base 10 and having the rotary axle 13 of the motor coupled by means of an ex-centric device to the plurality of chambers 1, 3, or at least the first chamber 1 and the possible one or more second chambers. The vibratory means 12 are intended for vibrating the plurality of chambers 1, 3, or at least the first chamber 1 and the possible one or more second chambers, in an upward and downward motion, but preferably also in a sideway rotary motion.
The upward and downward motion results in at least a liquid fraction 16 of the manure not being retained in the first chamber 1 more easily passing to the third chamber 3. If one or more second chambers are provided, the upward and downward motion also results in smaller particles of the solid fraction of the manure not being retained in the one or more second chambers more easily passing to the third chamber 3, or even smaller particles the solid fraction of the manure not being retained in a sequentially initial second chamber more easily passing to a sequentially subsequent second chamber.
The sideway motion results in particles 31 of the solid fraction of the manure being retained in the first chamber 1, in the optional one or more second chambers, and at least the liquid fraction 16 being retained in the third chamber 3, respectively, being led to chamber side walls 17, 19 constituting lateral boundaries of the chambers 1, 3, respectively.
The rotary motion results in the particles 31 of the solid fraction of the manure being retained in the first chamber 1, in the optional one or more second chambers, and at least the liquid fraction 16 being retained in the third chamber 3 being led circumferentially
along the chamber side walls 17, 18 towards possible outlets 21, 23 provided in the chamber side walls 17, 19.
The particles 31 of the solid fraction being larger than the mesh-size of the first screen 5 are retained in the first chamber 1. The remaining part of the manure, i.e. the liquid fraction 16 and possible smaller-sized particles of the solid fraction, passes through the first screen 5 and into the third chamber 3. If one or more second chambers are provided, the remaining part of the manure, i.e. the liquid fraction and the smaller-sized particles of the solid fraction, passes through the first screen 5 and into the second chambers.
If one or more second chambers are provided, the smaller-sized solid particles of the solid fraction being larger than the mesh size of the second screen are retained in the second chamber. The remaining part of the manure, i.e. the liquid fraction and possibly even smaller-sized solid particles of the solid fraction, passes through the one or more second screen and into the third chamber. The liquid fraction and the possible even smaller-sized solid particles of the solid fraction are retained in the third chamber.
Preferably, the first chamber 1, the optional one or more second chambers, and the third chamber 3 are each provided with outlets 21, 23 for letting out the fractions of the manure, which are retained in the chamber in question. Thus, the first chamber 1 is provided with a first outlet 21 for letting out particles 31 of the solid fraction, the optional one or more second chambers are provided with second outlets for letting out smaller- sized particles of the solid fraction, and the third chamber 3 is provided with a third outlet 23 for letting out the liquid fraction 16 and the possible even smaller-sized particles of the solid fraction.
The outlets may be provided in any suitable manner, but preferably the outlets are provided tangentially to the circumference of the chambers. However, in alternative embodiment, the outlets may be provided radially to the circumference of the chambers, and the third outlet may even be provided axially, either in the centre of bottom of the third chamber or off-set in relation to the centre of the bottom of the third chamber.
The mesh size of the first screen and the mesh size of the optional one or more second screens may vary depending on the livestock, which the manure originates form, and depending on the demand or desire for separation, i.e. how large the larger-sized fractions has to be or is intended to be, and how small the smaller-sized fractions has to be or is intended to be. Preferred mesh-sizes of the first screen 5 are between 50 μm and 500 μm, and preferred mesh-sizes of the second screen 7 are between 10 μm and 250 μm.
In the embodiment shown, the screw press is provided as a method step of separation being initial to the step of vibratory separation. However, as mentioned, in an alternative embodiment, the screw press may be provided as a method step of separation being subsequent to the step of vibratory separation.
As mentioned, results from use of the apparatus according to the invention demonstrate a very high separation capacity compared to separation capacities of prior art apparatuses. The very high separation capacity is mainly due to the at least two steps of separation of the solid particles. At least two steps of separation of the solid particles increase the separation capacity, however, without the use of two apparatuses. Also, the use of at least two separation steps renders the possibility of tuning the mesh size of each of the separation steps in respect of the texture, the content and the flow rate of the waste material, and still by only using one apparatus for performing an optimum separation by vibration.
Results show that when between 10 and 20 cubic meters of total volume of animal manure waste material is passed to an apparatus according to the invention and involving a pressurising process preliminary to the vibration process, between 6% and 10% of the total volume, i.e. between 0.6 and 2.0 cubic meters of larger-sized solid particles of the waste material is separated in the first chamber. The percentage of larger-sized particles being separated very much depend on the animals form which the waste material originates, and also depends on the constituents of the waste material, partly depending on the kind of feedstock, which the animals have been fed.
Results also show that when between 10 and 20 cubic meters of a total volume of animal manure waste material is passed to an apparatus according to the invention and involving a pressurising process preliminary to the vibration process, between 1% and 6% of the total volume, i.e. between 0.1 and 1.2 cubic meters of smaller-sized solid particles of the waste material is separated in the second chamber. As is the case with the larger-sized particles, also the percentage of smaller-sized particles being separated very much depend on the animals from which the waste material originates, and also depends on the constituents of the waste material, partly depending on the kind of feedstock, which the animals have been fed.
Any part of the solid fraction being removed from the first chamber and/or from possible one or more second chambers may be passed further on to a screw press subsequent to the vibratory separation apparatus for being further separated in a subsequent separation method step into a solid fraction having a higher dry matter content.
Alternatively, or additionally, the liquid fraction being removed from the third chamber may be passed further on to a screw press subsequent to the vibratory separation apparatus for being further separated in a subsequent separation method step into a liquid fraction having a lower dry matter content.
In a possible embodiment of a vibratory separation apparatus, not necessarily a vibratory separation apparatus according to the invention, but preferably according to the invention, addition of an acidifying substance may be provided. An acidifying substance may be added to the manure before the manure is passed to the first chamber, or may be added to the manure when the manure is passed to the first chamber, or may be added to any remaining part of the manure at any separation step between the first step of the method according to the invention, i.e. passing the manure to the first chamber, and the final step of the method according to the invention, i.e. passing the manure from the third chamber 3.
Additionally, or alternatively, it will be possible adding an acidifying substance at more than one location along the separation process, possibly adding an acidifying substance before or when the manure is passed to the first chamber and also adding an acidifying substance when the manure is passed to one or more of the possible subsequent second chambers.
The acidifying substance may be any acidifying substance, but preferred acidifying substances are chosen among the following substances: acids themselves such as H 2 SO 4 , HCI, HNO 3 , H 3 PO 4 or other acids themselves, or acid-containing component such as Fe 2 (SO 4 ) 3 , AI 2 (SO 4 J 3 or any other acid salt or other acid-containing components.