CN1074651C

CN1074651C - A method and an apparatus for producing plant nutritive strings or pellets from wastewater sludge

Info

Publication number: CN1074651C
Application number: CN94106902A
Authority: CN
Inventors: 托斯滕·莫迪格
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-06-01
Filing date: 1994-06-01
Publication date: 2001-11-14
Anticipated expiration: 2014-06-01
Also published as: CN1113684A

Abstract

The present invention relates to a method and a device for producing plant nutrition columns or particles from sludge produced by waste-water treatment plants. The method and the device can directly make the sludge into columns or particles, which can prevent aggregates from being produced; consequently, the columns or the particles can be effectively dried so as to make water content reduced to 10-15%, and therefore, the columns or the particles are favorable for bagging and storage.

Description

The method and apparatus of production plant nutrition bundle or particle from wastewater sludge

The present invention relates to the method and apparatus of from the mud that wastewater treatment produces production plant nutrition bundle (strings) or particle.

Although contain valuable nutrient for plants in the mud,, the mud major part that produces in the wastewater treatment plant is deposited on the soot.It is main if it were not for the heavy metal of worrying in the mud to trace it to its cause, and main be that the peasant is difficult to dispose continuously such mud.Previously once attempted to make mud directly form particle, but find that this is impossible, reason is sludge moisture content height (70-80%) thereby short texture.The percentage composition that wants reduction water in the sludge treatment process also is impossible, because most water is in bag pencil attitude in the mud.In addition, the very sticking very fast bonding of particle that causes being generated of mud forms very big aggregation together.These bulks may be parched the degree that water content is reduced to be enough to store hardly.Mud in batch still is a kind of public hazards of communicate illness, because wherein contain infectious material all the time, and for example salmonella, various virus and parasitic ovum.

The present invention aims to provide the method and apparatus of above-mentioned this sludge treatment, this method can directly be made mud pencil or particle, avoid producing aggregation, so just sludge-drying bundle or particle effectively, make its water content be reduced to about 10-15% and be suitable for storing, in disposal process, also can eliminate the harm of communicate illness simultaneously.Characteristics of the present invention are open in appended claims.

According to the present invention, a kind of method and apparatus now is provided, can realize purpose of the present invention by splendid mode.Can obtain following benefit by granulation.When mud bundle or particle are extruded from extruder, spray with preferred hygroscopic powder, thereby can make the mud hardening keep its shape.The coating dry powder can prevent that also it from bonding together and form aggregation, and can make it be easy to rapid draing.But the dry powder of moisture absorption absorbs moisture rapidly from the surface of the bundle just made or particle, then, these moisture are promptly taken away under the hot drying gas atmosphere of rotary drum.After powder parches, promptly be scattered from bundle or particle, thus can be recycling during the course.Particle or the bundle that splits voluntarily can make moisture be reduced to about 10-15% as the drying of cereal by routine to be suitable for storing.Like this, particle produced according to the invention just can be carried in the time that is suitable for agricultural demand owing to can store.In addition, can take the similar mode of using artificial manure to spray, thereby replace a large amount of fertilizer.By particle being heated to 80 ℃, 15 seconds time, can prevent the danger of communicate illness.Adopt modern hot swapping to carry out drying according to the present invention and granulation energy expense is very low.

By embodiment preferred and consult accompanying drawing, the present invention is described in detail below, wherein,

Fig. 1 be in order to the device schematic diagram of realizing the inventive method and

Fig. 2 is the magnification ratio schematic diagram in extruder nozzle and cross section, aperture, wherein, be equipped with annular, along the slotted nozzle of circumference in order to blowing out pressurised air.

Fig. 1 is used for the mud production plant nutrition bundle that produces from wastewater treatment or the device schematic diagram of particle.Adopt extruder 1 to carry out granulation, mud 2 is pushed through at least one nozzle 3 by extruder, and this nozzle 3 has a jet hole 4 at least.In illustrative embodiment, nozzle 3 has many jet holes 4 that are abutted against arrangement each other, and mud can be squeezed into many particle beam that are parallel to each other 5 after by jet hole.Cutter sweep (not being shown specifically among the figure) is used for being about to be cut to particle 6 separately under the situation of granulation when particle beam 5.In some cases, be not cut into particle separately after particle beam generates, they can break voluntarily owing to enbrittle.Shown in Fig. 2 cross sectional representation, this cutter sweep can comprise from annular, along the compressed air stream of the slotted nozzle 29 of circumference.Make it easy to guide air flow to converge to the central authorities of nozzle 3 by this spray nozzle device of row.Fine wire also can be used for cutting particle, maybe can adopt any other suitable equipment.Yet air flow nozzles can play a part to get rid of because stickum produces sediments harm, deposits and can produce on scraper especially when adopting other method.Near jet hole 4, have at least a nozzle 14 to be used for powder 9 is sprayed at particle.Nozzle 14 is by suitable direction directional nozzle 3, so that blow the powder 9 that is entrained in the air flow 7, makes it fully to coat on particle beam of extruding 5 and/or the particle 6 that separates.In the embodiment according to the preferred embodiment of the invention, regulation can be sprayed with powder continuously or discontinuously.For other invention embodiment, can be naturally before particle beam 5 be cut, spray during cutting or after cutting into particle 6 separately.The inventive system comprises the rotatable rotary drum 12 that is positioned under the extruder 1, be provided with pit 10 in this rotary drum, wherein, can collect a certain amount of 8 particle 6 in order to collect the excess powder 11 of a great deal of.Pit 10 is arranged in airtight section 16 of rotary drum 12, and this airtight section is to assemble for rotation in the fixed component 13 of this device.Fixed component 13 can hold extruder 1, powder jet 14, is used for the air flow 7 of entrained powder 9, is used to aspirate the suction tube 15 of excess powder and the slotted nozzle 29 of ring-type.Away from rotary drum 12 ends of pit 10, with roll gap 17 synthetic operations, the particle 6 after the coating passes through from here, is transporter 18 under it in order to particle 6 is transported to transporter 19, and it is sent to the dry kiln of routine operation.Particle carries out preheating and is scattered up to the powder of coating in rotary drum 12, according to after the final drying of its known mode, the intensity of particle obtains enhancing to a certain degree in kiln.

As can be seen from Figure 1, prilling granulator of the present invention also can comprise the feed hopper 21 of pulverized limestone 9, and it can be by pipeline 22 chargings.Pulverized limestone 9 is discharged on the transporter 23, and infeeds pipeline 26 by import 24 from here.It is contemplated that and spray powder in different ways, for example use compressed air.When taking this mode, directly draw powder with special vacuum nozzle, so that subsequently powder is sprayed on the nozzle 3 of extruder from feed hopper 21.Fig. 1 shows the fan blower 25 in the pipeline 26, is used for air and pulverized limestone 9 are mixed, so that entrained powder is delivered to nozzle 14 by pipeline 26 in air flow 7.Powder 9 in rotary drum around rotation or in pit 10, generate material 11, can Returning utilization, extract out by pipeline 15 by fan blower 27, and then rise to cyclone separator 20 (filter being housed, not shown).Powder 9 is discharged into feed hopper 21 by cyclone separator 20.The air that returns from cyclone separator flows into refrigerator pipes groups 30 by pipeline 28, so that cooling and dehydration then by heating tube group 31, enter rotary drum 12 subsequently, like this, it is very low just can to guarantee to enter the contained moisture of the air of rotary drum.That does like this is intended that these air can produces strong turbulent flow in rotary drum, so that excessive powder pitches on the particle, thereby it can be reused.

By said apparatus, the method that the present invention takes is as follows: the mud from wastewater treatment plant infeeds (not elaborating at this) by certain mode, by extruder 1, it is pressed through the nozzle 3 of extruder, the latter is equipped with many jet holes 4, by this jet hole, mud transfers to form particle beam 5 separately, that be parallel to each other.After it draws off from jet hole 4, by from annular, along the slotted nozzle 29 of circumference, these bundles 5 are cut into single particle 6, in particle beam when jet hole protrudes, and/or after cutting into particle, with being entrained in airborne powder continuously to its spraying.The purpose of spraying is to make it dry easily, makes the particle beam hardening, avoids forming aggregation from the particle of jet hole 4.When spraying was carried out, rotary drum 12 was still rotating, so, fall into wherein particle 6 can be effectively by in the pit 10 and the powder of bottom of the drum constantly be coated on its whole surface.Particle 6 leaves pit 10, moves forward and arrive the end away from the rotary drum 12 of pit along the inner casing surface of rotary drum 12, then, drops on the transporter 18 for 17 times by cracking, and is transported to transporter 19 it is sent into the dry kiln (not shown).Adopt known technology in kiln, to be dried, make its water content reach about 10-15%, to be suitable for storage by preset time.In preferable methods is implemented, with this particle dry run an operation in for example be heated to about 80 ℃ with micro-wave oven, the time is 15 seconds.The metering of the suitable consumption of dusty spray is relevant with the excess powder of the ability of extruder and circulation, can adjust as required.Owing to use the drystone ashes, dry run is become be easy to carry out, by dusting the water content in the particle is reduced.

Add pulverized limestone and can not make the disposal costs of mud more expensive significantly, because wastewater treatment plant will add lime (about 200-300 kg/ton mud siccative) usually.From the angle of plant nutrition, after the mud that lacked lime originally adds lime, can make it more favourable to agricultural.Yet, add lime and also have problem, because shift the loss that causes nitrogen owing to alkalinization makes the ammonium hydrate.Surface with the pulverized limestone coating particle can not produce a large amount of nitrogen losses as lime being sneaked into whole materials.With powder coating alkalized in the surface of useful effect, and the loss of nitrogen can not take place because in fact chemical process stops to carry out under low moisture content at lay up period in dried particle.Therefore can think that compare with untreated mud, the mud nitrogen content after the granulation is higher.

Claims

1. the method for production plant nutrition bundle or particle from the so-called primary sludge of wastewater treatment plant, the water content of this mud is 70-80%, mud does not further dewater and carries out granulation, powder is used for stabilized beam or particle, to avoid it to bond together, the method is characterized in that at mud and generate at least one particle beam and after the generation bundle finally is cut into particle, add powder, with the air flow sprinkling particle beam of entrained powder or the particle after the cutting, thereby the intensity of soft particle beam and/or cutting back particle is improved, form particle aggregate when avoiding the particle after collecting bundle and/or cutting subsequently, make drying thereafter be easy to carry out, thereby the moisture that obtains being scheduled to is 10-15%, is suitable for storing.

2. according to the method for claim 1, wherein adopt extruder (1) granulation, by this extruder mud is pushed nozzle (3) at least one extruder that is equipped with at least one extrusion nozzle mouth (4), be equipped with many mutually near this jet hole of arranging, by this jet hole, mud is extruded and forms many separate, particle beam of being parallel to each other, after the method is characterized in that described bundle draws off from jet hole (4), be cut into single particle, meanwhile, spray particle beam and/or particle continuously with air flow and its powder of carrying secretly.

3. according to the method for claim 1 or 2, the powder that it is characterized in that being entrained in directional nozzle mouth (4) in the air flow is a pulverized limestone, the spraying earlier of this pulverized limestone is from the particle beam of jet hole protrusion and the particle after the cutting, at this moment, this particle is in the preceding air zone of nozzle (3), drops into the pit (10) under the nozzle (3), and described pit (10) has the leeway of depositing material.

4. according to the method for claim 1, it is characterized in that in the superfluous lime powder, rotating with the particle after the superfluous lime coating, can collect in the bottom of rotary drum (12), described particle is by (17) discharging from rotary drum of cracking, and is recovered from the superfluous lime that particle is scattered.

5. each method in requiring according to aforesaid right, grain flow behind the coating powder that it is characterized in that coming from rotary drum (12) by crack (17) is transported to dry kiln (19), particle carries out drying by the given time in this kiln, moisture can be reduced to 10-15% like this, subsequently, the particle pack is stored.

6. according to the method for claim 5, it is characterized in that this mud or particle heat to eliminate malignant bacteria, parasitic ovum in process.

7. the device of cover production plant nutrition bundle or particle from the mud that wastewater treatment plant produces, this device comprises the extruder (1) that is equipped with at least one jet hole (4) on its nozzle (3), in order to mud is made at least one particle beam, be used for particle beam is cut into the device (29) of particle in addition, this device is characterised in that to have an air-blast nozzle (14) with jet hole (4) synthetic operation at least, be used to spray powder, described powder is entrained in the air flow, the particle that blows to described particle beam and finally cut into from described particle beam, this device be characterised in that extruder (1) be fixed member (13) around, and launch forward, lowermost extent at rotation rotary drum (12) has excessive powder, it is characterized in that, this rotary drum (12) opens wide at least one transporter (18,19), by crack (17), particle after the dusting further is transported to dry kiln, and particle in this kiln (6) drying in the given time reaches predetermined moisture.

8. according to the device of claim 7, it is characterized in that suction tube (15) in order to the suction excess powder extends and passes fixed component (13), the opening of locating with rotary drum (12) airtight section (16) connects, and extruder (1) also is positioned at this place.

9. require 7 or 8 device according to aforesaid right, the cutter sweep (29) that it is characterized in that being used for particle comprises the compressed-air atomizer of ring-type, and the central authorities of this nozzle guiding extruder nozzle (3) are in order to cut particle beam discontinuously.