WO2010057499A1

WO2010057499A1 - Method and apparatus for manure treatment

Info

Publication number: WO2010057499A1
Application number: PCT/DK2009/050306
Authority: WO
Inventors: Lars Leth Pedersen
Original assignee: LLP HOLDING, ASÅ ApS
Priority date: 2008-11-18
Filing date: 2009-11-17
Publication date: 2010-05-27
Also published as: EP2365943A1

Abstract

The present invention concerns a method and a plant for treating liquid manure wherein an isolated portion of liquid manure goes through at least one process, by which process the manure is treated with ozone, where ozone is formed in an ozone generator, where added ozone reacts with liquid manure in a closed volume. It is the object of the invention to remove disagreeable smell from liquid manure. Another object is to break down lumps in liquid manure. The object may be achieved by a method or by a plant wherein the ozone treatment occurs in a closed volume in the shape of a pipe system in which the liquid manure is circulated by a pump, where ozone is added to the circulating portion of liquid manure. Hereby may be achieved that a relatively large concentration of ozone is continuously in contact with the same portion of liquid manure in that the liquid manure together with ozone is pumped around in the pipe system. By pumping it through the pipe system, a complete or partial mixing of liquid manure with ozone is effected such that the ozone is provided good opportunity to attack and decompose organic compounds in order for the organic molecular chains to become shorter.

Description

Method and apparatus for manure treatment

Field of the Invention

The present invention concerns a method for treating liquid manure wherein an isolated portion of liquid manure goes through at least one process, by which process the manure is treated with ozone, where ozone is formed in an ozone generator, where added ozone reacts with liquid manure in a closed volume.

The present invention also concerns a plant for treating liquid manure, wherein the plant includes at least one reactor tank, the plant including an ozone generator formed by at least one compressor pressing air through a longitudinal container, the container containing at least one UV-source for ozone generation, where ozone-containing air is supplied to the reactor tank.

Background of the Invention US 6,056,885 discloses a process in which liquid manure is conducted into a closed compartment. Ozone is let into the bottom of the compartment and bubbles through the liquid manure under active admixing. Hereby, ozone reacts with "components" in the liquid manure such that a disinfected, decontaminated and smell reduced end product is achieved.

Wu et al. J., Agric. Engng Res. (1999) 72, 317-327, disclose how ozone eliminates the concentration of smelling bacterial metabolites. This effect is not achieved by using nitrogen or pure oxygen. The article describes various concentrations of ozone combined with various times of storage. The effect of smell reduction is observed manually as well as measurements of concentrations of i.a. phenol and skatole are performed.

Object of the Invention

It is an object of the invention to remove disagreeable smell from liquid manure. Another object is to break down lumps in liquid manure. A further object is to increase the actual fertiliser value of liquid manure. Description of the Invention

The objects may be achieved by a method as specified in the preamble of claim 1 wherein the ozone treatment occurs in a closed volume in the shape of a pipe system in which the liquid manure is circulated by at least one pump, where ozone is added to the circulating portion of liquid manure at at least one point.

Hereby may be achieved that a relatively large concentration of ozone is continuously in contact with the same portion of liquid manure in that the liquid manure together with ozone is pumped around in the pipe system. By pumping it through the pipe system, a complete or partial mixing of liquid manure with ozone is effected such that the ozone is provided good opportunity to attack and decompose organic compounds in order for the organic molecular chains to become shorter. Also, ozone will cause complete or partial sterilisation as cell walls of bacteria become perforated by ozone such that the bacteria die. The mixing through the pipe system may be further improved if the circulation in the pipe system is turbulent. A number of bends on a pipe connection will automatically entail a turbulent flow. Likewise, different types of pumps will entail a not too constant flow speed such that increased turbulence may also be achieved by the pump design. The admixed ozone in the pipe system has thus no possibility of evading but is forced to stay, however as a gas in the form of bubbles in a circulating liquid. The actual reaction time for ozone in the course through the pipe system is thereby increased.

By utilising the efficient ozone treatment in the pipe system it may be achieved that the liquid manure changes its colour from brown to grey, and at the same time is achieved that the liquid manure becomes odour-less.

The liquid manure may be circulated in a pipe system which can be designed with a total length between 60 m and 400 m with a flow rate of about 5,000 I/hour. The length of the pipe system is important in order for the ozone process to proceed with sufficient certainty. Of course, this invention may also be provided by shorter pipe systems, only working at a lower pumping rate such that the actual retention time is unchanged. By faster pumps and possible addition of further and greater amounts of ozone, it may also be possible to work with substantially longer pipe systems. The pipe system begins and ends in a liquid manure tank, to which liquid manure tank fresh liquid manure may be supplied from a stable, and from which liquid manure tank treated liquid manure may be conducted for storage in a slurry container. Using a liquid manure tank for liquid manure between a stable system and an actual liquid manure storage container is commonly known in beforehand. However, the invention may here be performed by providing ozone treatment of the liquid manure on the way to this liquid manure tank.

By liquid manure treatment, the liquid manure tank may be isolated by closing valves towards stable and slurry container, respectively. By means of valves it may thus be possible isolate the portion of liquid manure located in the liquid manure tank and the pipe system such that this defined portion of liquid manure can be subjected to repeated ozone treatments.

During the treatment of liquid manure, the pump may suck from the liquid manure tank after which the pump may press the liquid manure through the pipe system. In order to ensure constant circulation through the pipe system, it is necessary to use a pump. The pump may advantageously suck from the liquid manure tank and press the liquid manure through the pipe system and back to the liquid manure tank. Actually, the pump may be located at any point in the pipe connection, but due to possible service of the pump it is most expedient that the pump is provided close to the beginning of the pipe system.

The pipe system may be supplied with ozone from at least one ozone generator through at least one pipe insert. As the liquid manure is circulating all the time, there is thus no need for further stirring, and ozone may advantageously just be introduced through a pipe with a number of small holes screwed into the pipe wall. Depending on the liquid manure capacity to be achieved, one may possibly add ozone at several points on the pipe connection.

The ozone treatment may be repeated by continuous circulation and ozone treatment for a period of time, the period of time possibly being determined from a change in colour in the liquid manure from brown to grey. The pump may thus perform several circulations of a portion of liquid manure such that the liquid manure of the liquid manure tank is circulated several times through the pipe system. Thereby may be achieved a very long total reaction time for the liquid manure pumped around in the system. When the process has been performed such that all the liquid manure has been treated, a change of colour from brown to grey will occur in liquid manure. In order to ensure that the liquid manure treatment has been performed completely, the treatment will continue for a further period of time in order to ensure that a totally odourless and sterile portion of liquid manure has been achieved.

Advantageously, an electric neutralisation of the through-flowing liquid manure may be performed by at least one earth connection. By providing an earth connection directly to the circulating liquid manure in the pipe system, an electric potential neutralization of local voltage differences occurring in the circulating liquid manure, even down to molecular level, may be achieved. Electric fields that may arise in the circulating liquid manure may thereby be neutralised. Together with ozone action, potential neutralization by means of earth connection have a very favourable effect on the circulating liquid manure.

The purpose may also be achieved by a plant as specified in the preamble of claim 9, if the plant includes a pipe system and a liquid manure tank, where ozone-containing air may be supplied to the pipe system through at least one nozzle unit, where the pipe system begins and ends in a liquid manure tank, and where the pipe system includes at least one pump.

Hereby may be achieved conversion of fresh liquid manure to liquid manure having the same contents of nutrients, but which is odourless and largely sterile. Addition of ozone-enriched air to a pipe system ensures that the air bubbles remain in contact with liquid manure while the portion of liquid manure circulates in the pipe system. Good mixing may be effected in the pipe system such that the liquid manure is effectively treated with ozone. The liquid manure tank is supplied with fresh liquid manure through a pipe connection from a stable, where the liquid manure is conducted through a further pipe connection to a slurry tank after end of the treatment. The liquid manure tank may advantageously be filled with fresh liquid manure directly from the stable over a period of time, after which the connection to the stable is shut off, e.g. by stopping a pump, and by means of valves a possible connection to an actual slurry container is closed also. The isolated portion of liquid manure may then be subjected to ozone treatment by circulation through the pipe system.

The liquid manure tank includes a first valve for closing the connection towards the stable, where the liquid manure tank includes a second valve for closing the connection to the slurry container, where the first and the second valves are closed during treating of liquid manure. By shutting off the portion of liquid manure in the liquid manure tank and the pipe system, it may be ensured that it is the same liquid manure portion that repeatedly passes through the pipe system and is subjected to ozone treatment.

The liquid manure tank may be designed with a size such that the tank may contain liquid manure supplied from a stable facility over a period of several days. The liquid manure treatment may be performed through at least one pipe connection which may be designed with a length between 200 and 400 m, where the treatment of liquid manure may be continued until at least change of colour occurs in the liquid manure. The treated liquid manure may subsequently be pumped from the liquid manure tank to storage in at least one slurry container. Hereby may be achieved that ozone treatment of liquid manure may possibly only occur once a week. The energy consumption by the ozone treatment is thereby reduced as the ozone system and the pump are only to operate relatively few hours a week.

By an alternative embodiment, the plant may be entirely or partially contained in at least one container, where the pipe connection runs internally of the container, preferably along the container walls, the container including a pump for circulating the manure as well as at least one ozone generator. By incorporating the entire liquid manure treating plant into one or more containers, a mobile treatment plant is thus provided which can be moved between various liquid manure producing farms, and it is achieved that a farmer can hire a liquid manure treatment plant for a shorter or longer period of time, e.g. at a machine pool. Also, several farms may cooperate about liquid manure treatment as a container-based plant can be moved in a relatively simple way between the individual farms, and the expenses of purchasing a liquid manure treatment plant may be shared. If a large farm wants rapid installation of a liquid manure plant, it will be a further advantage that a container solution does no require a building permit in the same way as a permanent installation. A container solution may therefore be the initial solution for a large farm, while a permanent plant can be installed subsequently when the effect of the liquid manure treatment is known and when the necessary building permits have been issued.

The container may include at least one liquid manure tank. The container may be connected to at least one first suction pump for filling the liquid manure tank. Also, emptying the liquid manure tank may be performed with a suction pump. A circulation pump is used for circulating liquid manure in the pipe connection. The container may also contain at least one ozone generator from which ozone is supplied to the pipe connection through at least one pipe. A complete liquid manure treatment plant may be contained in e.g. a 40 feet container as the pipe connection for ozone treatment of the liquid manure may run along the three internal container walls, while a relatively large liquid manure tank maybe provided at the centre of the container, where the liquid manure tank may be filled e.g. by means of a submersible pump which by means of a crane can be lowered down into an existing liquid manure installation. When the internal liquid manure tank is filled, the process may start, and in the pipe connection repeated treatment with ozone may take place until the contents of the liquid manure tank have been transformed. When the contents of the liquid manure tank have been treated, the same or another submersible pump may be lowered into the liquid manure tank, and the tank may then be emptied. By making the complete liquid manure treatment plant in a large container, it will be possible to perform a mass production of liquid manure treatment plants, and depending on the actual use the containers may either be permanently mounted in connection with a farm or be moved from farm to farm. Advantageously, the pipe connection may include an electric earth connection, the earth connection including at least one electrode with electric connection to the circulating liquid manure. In practice, it has appeared that earth connection of the circulating liquid manure simultaneously with the addition of ozone has a favourable effect on the liquid manure conversion taking place in the pipe system. By making an earth connection, electric potential differences will be neutralised, and together with the action of ozone is achieved a very efficient transformation of liquid manure such that the liquid manure is largely sterilised, and where at the same time binding of ammonia is effected such that ammonia dissolved in the liquid manure is converted to ammonia salts such that evaporation of ammonia from the processed liquid manure is avoided.

Description of the Drawing

Fig. 1 shows a possible embodiment of a plant for treating liquid manure. Fig. 2 shows an ozone generating plant as indicated on Fig. 1 in the well 16. Fig. 3 shows a container containing a liquid manure plant. Fig. 4 shows a container with internal pipe connection.

Detailed Description of the Invention

Fig. 1 shows a possible embodiment of a plant for treating liquid manure. By reference numeral 2 on Fig. 1 is shown a complete plant consisting first of a stable 4 where a liquid manure collecting well 6 is provided. This liquid manure collecting well may be provided with a pumping device. From the liquid manure collecting well 6, a pipe connection 8 leads to a liquid manure tank 10. From this liquid manure tank 10 a connection 12 goes on to a pump 14 through a further service well 16 and to a shutoff valve 18. At the other side of the shutoff valve 18, the pipeline continues into an actual slurry container 22 for long term storage. At a branch placed immediately before the valve 18 is found a pipe connection 20 which is winding in order to provide the greatest possible length, where the pipe connection 20 returns to the liquid manure tank 10.

During normal operation, liquid manure will be pumped from the stable facility 4 through the channel 8 into the liquid manure tank. In this phase, the pump 14 will be stopped and the liquid manure tank 10 will be filled. This will probably happen in about a week's time. When sufficient amount of liquid manure is present in the liquid manure tank 10, the valve 18 is closed and the pump 14 is started, after which the ozone facility 16 is activated. The ozone facility 16 thus adds ozone to the amount of liquid manure pumped around in the pipe connection 20. The pumping occurs continuously with a pump that yields about 5000 litres per hour through a pipe connection with a diameter of 160 mm. The treatment of the liquid manure continues for a longer period of time until a change in colour has been ascertained in the liquid manure. The liquid manure changes colour from brown to grey, and about simultaneously with this colour change, the liquid manure becomes free from disagreeable odour. After the change in colour, the pump 14 continues its operation for a further period of time in order to ensure that the whole portion of liquid manure has achieved treatment. When the whole liquid manure portion has been treated, the valve 18 is opened and the pump 14 now pumps the processed liquid manure into the slurry container 22 where the liquid manure may be stored for extended period of time. The processed liquid manure now coming into the slurry container 22 is thus odourless and will not in any way give off repelling odours to the surroundings. At the same time, the liquid manure is completely fluid as no solid particles are contained in the liquid manure, whereby actual stirring and pumping of the liquid manure is considerably facilitated when the liquid manure is to be brought out on the fields, as pumps are less liable to be clogged. A further advantage by the invention is achieved when the liquid manure is spread on the fields as the liquid manure is completely free from disagreeable smells when brought out.

Fig. 2 shows an ozone generating facility as indicated on Fig. 1 in the well 16. The ozone facility 102 contains a compressor 104 with an air suction inlet 106. Compressed air is conducted through a pipe connection 108 to a pressure regulator 110. The air is now sent on with reduced pressure through a pipeline 112 to a flowmeter 114. From here the air conducted to an ozone generator 116 containing a source of UV-light 118 which may be a pipe. Ozone-containing air is now sent through a pipe connection 120, through a return valve 122, through a screw joint 124 comprising a nozzle unit 126 which is provided in a pipe wall for a liquid manure channel 128. Furthermore, there is shown an insert 130 in liquid manure channel 128. The insert 130 is an earth connection which is electrically connected to earth. During operation, the compressor 104 will provide air supply to the ozone generator 118, and by means of pressure regulation 110, an air flow through the flowmeter 114 is set to 20-25 litres per minute. Thereby is formed a relatively large amount of ozone in the ozone generator 116, and this ozone is then supplied to the liquid manure pipe 128 through pipe connection 120. The return valve 122 only has the purpose of avoiding that liquid manure penetrates up into the ozone generator 116 at times when the system is not in operation. The earth connection 130 has the object of ensuring an actual earthing of the liquid manure circulating the pipe system. The earth connection means that possible excess electrons released by the ozone process, or a corresponding deficit of electrons is equalised through this earth connection.

By adding 20-25 litres of air per minute with a high ozone content to a pipe 128, which typically can be 160 mm in diameter, and when the liquid manure amount is 5000 litres per hour, an efficient liquid manure treatment of a large amount of liquid manure can be attained in relatively few hours.

Fig. 3 shows a possible embodiment of a container 202 containing a complete liquid manure treatment plant. The container 202 is placed on a trailer resting on support legs 204 and also having wheels 206. The container 202 includes a liquid manure tank 210 which is fed through a suction line 208 which in principle here communicates with a suction pump, e.g. a submersible pump 242. The liquid manure tank 210 communicates with a slurry pump 214, and immediately after the slurry pump ozone is supplied in a pipe connection 220 by means of a ozone pipe stub 226. A gate valve 224 performs redirecting of the flow direction through the liquid manure treatment plant. If the gate valve 225 is closed, a flow through pipeline 220 takes place through pipeline 220 to the top of the liquid manure tank 210. This flow may e.g. take place through a large number of pipes running along the inner wall of the container. With the gate valve 224 in the opposite setting, circulation occurs along the bottom of the container. The container 202 may also include a crane 240 used for lowering the submersible pump 242 down into a well, or possibly down into another kind of liquid manure tank. Also, there is shown a submersible pump 218 which through a top hatch 244 may send liquid manure through a slurry hose to e.g. a slurry tanker 222 for immediate bringing out liquid manure on a field. Alternatively, when leaving the submersible pump 218 the liquid manure may instead be conducted to long term storage in a normal slurry container.

Fig. 4 shows a container 302 where an external pump 314 through a hose or pipe 316 pumps liquid manure into a pipe connection 320 running along the inner wall of the container 302. The liquid manure leaves the pipe system again through a hose or pipe connection 322. The pipe connection 320 contains a pipe stub for introducing ozone 326, and an earth connection 330 is shown. The invention according to Fig. 4 may be incorporated in a 20 feet container, and here it is possible to treat liquid manure from any other kind of slurry container, e.g. a large external slurry container, and which is desired to be treated. By means of the pump 314, it here becomes possible to pump liquid manure through the system and let the liquid manure return to the large tank. It will take relatively long time if a very large tank is to be processed, but it will definitely be possible to perform this process. Another way of using the invention shown on Fig. 4 may be a farm with a liquid manure tank where fresh liquid manure is stored before the liquid manure is pumped into the slurry container itself. The container solution shown on Fig. 4 may thereby be used for emptying and treating fresh liquid manure from the liquid manure tank and after finishing, the treated liquid manure may be pumped over into a slurry container for long term storage, or the liquid manure may be pumped directly into a slurry tanker for bringing out.

By the invention is achieved that odour nuisances from liquid manure are completely eliminated. At the same time, the fertiliser content in the liquid manure is increased. This increase of the fertiliser content has primarily occurred by highly soluble ammonia contained in the liquid manure reacting by the ozone treatment such that ammonia salts, which are sparingly soluble, are formed. Thereby evaporation of ozone is prevented during storage of the liquid manure. The increased fertiliser value is so great that the amount of artificial fertiliser to be used when fertilising with treated liquid manure is much reduced. By increasing the amount of fertiliser compared with traditional application of liquid manure, and by maybe entirely avoiding the use of artificial fertiliser, this invention may entail substantial energy savings and a substantial reduction of the CO₂ load from farming.

Claims

1. A method for treating liquid manure wherein an isolated portion of liquid manure goes through at least one process, by which process the manure is treated with ozone, the ozone being formed in an ozone generator (16, 116), where supplied ozone reacts with liquid manure in a closed volume (20,128,220,320), characterised in that the ozone treatment occurs in a closed volume in the shape of a pipe system (20,128,220,320), in which pipe system (20,128,220,320) the liquid manure is circulated by at least one pump (14, 214), where ozone is added to the circulating portion of liquid manure at at least one point.

2. Method according to claim 1, characterised in that the liquid manure is circulated in a pipe system (20,128,220,320), the pipe system (20,128,220,320) having a total length between 60 m and 400 m.

3. Method according to claim 2, characterised in that the pipe system (20,128,220,320) begins and ends in a liquid manure tank (10, 210), to which liquid manure tank (10, 210) fresh liquid manure is supplied from a stable (4), and from which liquid manure tank (10) treated liquid manure is conducted for storage in a slurry container (22, 222).

4. Method according to claim 3, characterised in that by liquid manure treatment, the liquid manure tank (10, 210) is isolated by closing valves (18) towards stable and slurry container, respectively.

5. Method according to claim 4, characterised in that during liquid manure treatment, the pump (14, 314) sucks from the liquid manure tank (10, 210), and that the pump (14, 314) presses the liquid manure through the pipe system (20,128,220,320).

6. Method according to claim 5, characterised in that the pipe system (20, 128) is added ozone from at least one ozone generator (16, 116) through at least one pipe insert (126, 226).

7. Method according to claim 6, characterised in that the ozone treatment is repeated by continuous circulation and ozone treatment for a period of time, the period of time being determined from a change in colour in the liquid manure from brown to grey.

8. Method according one of claims 1-7, characterised in that electric neutralisation of the through-flowing liquid manure is performed with at least one earth connection (130, 330).

9. A plant (2,102,202,303) for treating liquid manure, wherein the plant (2,102,202,302) includes at least one liquid manure tank (10,210), the plant (2,102,202,302) including an ozone generator (16,116) formed by at least one compressor (104) pressing air through a longitudinal container (116), the container containing at least one UV-source (118) for ozone generation, where ozone-containing air is supplied to the plant, characterised in that the plant includes a pipe system (20,128) and a liquid manure tank (10,210), that ozone-containing air is supplied to the pipe system (20,128,220,320) through at least one nozzle unit (126), that the pipe system (20,128,220,320) begins and ends in a liquid manure tank (10,210), and that the pipe system (20,128,220,320) includes at least one pump (14).

10. Plant (2,102,20,303) for treating liquid manure according to claim 9, characterised in that the liquid manure tank (10, 210) is supplied with fresh liquid manure through a pipe connection (8) from a stable (4), and that the liquid manure tank (10) is conducted through a further pipe connection (12, 18) to a slurry tank (22, 222) after end of the treatment.

11. Plant (2,102,202,302) for treating liquid manure according to claim 9, characterised in that the liquid manure tank (10, 210) includes a first valve for closing the connection towards the stable (4), that the liquid manure tank (10, 210) includes a second valve for closing the connection to the slurry container (18), where the first and the second valve (18) are closed during treating of liquid manure.

12. Plant (2,102,202,302) for treating liquid manure according to claim 10, characterised in that the liquid manure tank (10, 210) is made with a size such that the liquid manure tank (10, 210) may contain liquid manure of several days from a stable facility (4) which is supplied to the liquid manure tank (10, 210), that the liquid manure treatment is performed through at least one pipe connection (20,128,220,320) having a length between 60 and 400 m, that the liquid manure treatment is continued until at least change of colour has occurred in the liquid manure, and subsequently treated liquid manure is pumped from the liquid manure tank (10, 210) for storage in at least one slurry container (22).

13. Plant (2, 102) for treating liquid manure according to claim 8, characterised in that the plant is entirely or partially contained in at least one container (202, 302), where the pipe connection (220, 320) runs internally of the container, preferably along the container walls, the container including a pump for circulating the manure as well as at least one ozone generator.

14. Plant (2, 102) for treating liquid manure according to claim 13, characterised in that the container (202, 320) includes at least one liquid manure tank (210), and that the container (202) communicates with at least one first suction pump (242) for filling the liquid manure tank (210), and that emptying the container is effected by a suction pump (218), the container (202) including a circulation pump for circulating liquid manure in the pipe connection (220), and that the container (202) further includes at least one ozone generator from which ozone it supplied to the pipe connection through at least one pipe.

15. Plant (2, 102) for treating liquid manure according to one of claims 8-14, characterised in that the pipe connection (20,128,220,320) includes an electric earth connection (130, 230), the earth connection (130, 230) including at least one electrode having electric connection with the circulating liquid manure.