CA2510672C - Process for the complete treatment of animal excreta and odours within the livestock building - Google Patents

Abstract

This invention concerns the treatment of animal waste. After recovery of the liquid and solid excreta separately, this treatment specifically allows these excreta to be submitted to successive treatments which ensure respectively the purification and reuse of the liquid thus obtained and the transformation of the solid by drying and its stabilisation to generate a deodorised and fertiliser-rich bio solid.

Description

METHOD FOR THE GLOBAL TREATMENT OF ANIMAL DISEASES AND
ODORS INTEGRATED IN THE LIVESTOCK BUILDING.
DESCRIPTION
Field of the invention The present invention relates to a method for the overall treatment of animal waste and odors integrated into the livestock building in a concept of "Green building". More precisely, this process is characterized in that the feces and pork urine or other farm animals are recovered separately without the mix, immediately to their evacuation by the animals and then they are subject to Has successive treatments which respectively ensure the purification, the purification and the reuse of the liquid thus obtained and the transformation of the solid by stabilization and drying to generate deodorized biosolids rich in materials fertilizing.
Description of the prior art There is a variety of techniques for treating hog manure or other livestock in the world. The majority of these techniques use the recovery of excreta so that ieces, urine and water washing evacuated together from the breeding premises, being mixed, to be subject to subsequent treatments or used for storage and / or subsequent spreading on the agricultural land. The dung thus recovered commonly called slurry, according to current processing techniques, usually require the use of a first liquid-solid separation step, carried out by slurry separators (screw press, centrifuge or decantation physico-chemical), a second step purification biological part of the liquid part (aerobic or anaerobic) and stabilization Of the game solid (biological or chemical or thermal) and a last step of tertiary treatment the liquid part (chemical, electrochemical, membrane filtration). The recovery droppings by mixing feces, urine and washings in the case of small-scale processing facilities has a negative impact on subsequent steps treatment because of the operating costs. Treatment technologies slurry the most widespread in the world in terms of numbers of installations operational those who use as a first step a mechanical separation liquid / solid followed aerobic biological treatment by nitrification-denitrification (approximately 80% of commercial applications) or anaerobic treatment (approximately 20% of applications commercial). These technologies are economically attractive for of the individual or group pig farming facilities allowing treat at least 20 cubic meters per day of manure dung. For the farms having less of 20 cubic meters to be treated per day and unable to regroup, it is difficult to apply these technologies at a reasonable cost. ).
The US patent. No. 6,368,508 B1 provides a method and apparatus for a biological treatment of manure based on an anaerobic phase and a phase anoxia according to a very complex scheme and difficult to apply.
An environmental solution is offered by US patents. No. 5,078,882 and no. 5,538,529 and Canadian patent no. 2070246 that offer treatments aerobic and anaerobic slurry without completely eliminating the disadvantages of the solutions existing.
The US patent. No. 5,890,454 offers a simplified solution for control odors in pig houses based on treatment chemical with aluminum sulphate, but its overall effectiveness is limited.
The international patent application published in no. WO 2004/039734 A1 presents a slurry treatment process by a method of purification of the part liquid by electroflotation, but a step of preliminary separation liquid-solid is always necessary.
Canadian patent application no. 2,228,819 proposes a solution of slurry treatment based on the addition of cellulosic material that facilitates the separation liquid / solid which is followed by a series of treatments for the solid part and the part liquid. Another relatively simple solution for manure treatment is presented by Canadian patent no. 2200164, May the primary separation step liquid / solid is always necessary and in addition the addition of chemical substances is necessary (polymers and calcium carbonate).

-2-There are also manure treatment processes that use various steps of treatment according to very complex schema and which are characterized by a big energy consumption and by significant costs related to the achievement and exploitation, as described in US Pat. 6,692,642, No. 6,569,332 B2, no.
6,497,741 B2, no.
6,470,828 No. 6,846,343 B2, patent applications no. 2003/0201225 A1 no.
2001/0013497 A1 and 2003/0075501 A1, and international patent application published no. WO 2004/011,393 A1.
Methods of recovering feces and urine from animal waste we have always been subject to study and development, but in the current state of technical, they have several disadvantages which explain why they are very few marketed worldwide. Several breeders left it because of the does this according to current solutions, requires a lot of manpower and maintenance.
These methods also increase the risk of health contamination by because of the proliferation of flying insects and pathogenic bacteria in scuppers and the walls of the installation.
It has already been developed a system of recovery feces and urine based on a method using guitars in a "V" shaped culvert, and with a centrally channeled for urine isolation. The system gives some results on the plan for the separation of feces and urine but the disadvantages following are not solved: accumulation of compacted dry matter on inclined bases scuppers that hinder scratching; the still high water content of the solid part which is difficult to stabilize and / or dry due to compaction during scraping; the treatment of the liquid part and odor control of the solid part are realized with solutions costly. It is also known in the art another system of recovery feces and urine according to a conveyor drip method. This system comprises the advantage to reduce some of the disadvantages presented above, but without avoid the accumulation of solids under the conveyors of solids transport, the generation of smells and the proliferation of flies. In addition, the pre-drying on the conveyor implies high additional costs for the handling and stabilization of solid.

-3-Given the state of the art described above, the need for systems and methods for the treatment of animal production waste still remain to join the concept of a "green building", a livestock building who respects the the most severe environmental criteria. In addition to providing solutions economic the problems described above, the process proposed by this invention has several other technological advantages that will be discussed in detail lower in the detailed description of the invention.
SUMMARY OF THE INVENTION
According to a first aspect of the invention, the method for the treatment of animal dung is characterized in that the feces and urine of pork or others farm animals, are recovered separately, without mixing, immediately to the out of the droppings and then they are subjected to treatments successive respectively purification and reuse of the liquid thus obtained and the transformation of the solid by drying and stabilization to generate a deodorized biosolid and rich in fertilizers.
According to another main aspect of the invention the process is carried out according to the successive steps as follows a) primary recovery, ie recover separately feces and urine immediately at the exit of the droppings under the slats according to different methods, as for example, but not exclusively, the technique of V-shaped scraper, or the use of conveyors or scrapers as known in the art of present invention;
b) treating the liquid portion recovered in step a) by a treatment organic aerobic, preferably by trickling bed filter on support fixed bacteria, allowing simultaneous treatment of liquids, including urine, and stale air generated, followed an electrochemical purification treatment to disinfect and of completely deodorize the liquid part and thus obtain a purified liquid;

-4-c) rinsing the scuppers under slats with a part of the purified liquid at step b) and alternatively dispose continuously the residual purified liquid part at middle natural without storing the liquid part or storing it for irrigation;
d) pre-drying the feces solid material, for example, but not limitatively, on a solid evacuation conveyor followed by the stabilization and biological drying (composting) of faeces evacuated from building, and alternatively a final thermal drying for obtain a dry product to the desired dryness.
According to another aspect of the invention, the process can be carried out by treatment simultaneous urine and stale air of the building, or only by treatment of electrochemical purification to disinfect and deodorize the liquid part and thus obtain a purified liquid.
According to another aspect of the invention, the primary recovery is carried out by a system for evacuating solids under slats, for example, but not limitingly, scrapers operated by cables or conveyors to draining carpet, and by a liquid evacuation system provided with a rinsing device scuppers, as for example but not limited to a buffer tank drain by severity or a direct pumping system.
According to another aspect of the invention, the electrochemical treatment step can be replaced by a method of osmosis treatment.
Another object of the invention is to use a portion of liquid thus purified for carry out the rinsing of the scuppers under the slats. The treatment of the party liquid allows to obtain a rinsing water of the scuppers in sanitary security while reducing odors due to ammoniacal nitrogen. This rinsing water being clean and disinfected allows to carry out breeding with the highest sanitary standards and atmospheres interior, this which improves the comfort of animals and workers.

-5-According to another aspect of the invention, the electrochemical treatment of the liquid allows to obtain a purified water meeting the norms of rejection of the medium receiver or can be recycled for other uses.
According to another aspect of the invention, the treatment of the solid part which comprises a pre-drying treatment step of the feces, preferentially on a solid evacuation conveyor integrated into the livestock building, followed by a step of stabilization (thermal, biological or other) of feces, can generate a biosolid deodorized and rich in fertilizer.
The application of the process makes it possible to reduce the volumes of effluent (feces, urine and wash water) to have 80% compared to a spreading management slurry on cultivated land and produce clean, reusable water for washing of buildings and generate a dried biosolid, deodorized and rich in materials fertilizing.
As used herein, the term "evacuation" means the action of rejection or dejection of a solid or liquid residue by an animal, constituting the urine or the feces.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic view of the method according to one of the embodiments of the present invention.
DESCRIPTION OF PREFERENTIAL ACHIEVEMENTS
The present invention will now be described in its entirety with references at scientific documents or figures, from which the achievements Preferred embodiments of the present invention are demonstrated. This invention can however, include different variants or forms that should not be interpreted as being limited to the achievements as presented here. The different achievements are presented in the following description to illustrate the scope of the present invention to the person of the art.

-6-All patents, patent applications, articles or publications mentioned here, supra and infra, are incorporated by reference only.
In accordance with FIG. 1, feces and urine are recovered separately immediately out of the droppings, preferably directly to the place where the animal produces the droppings, in the breeding room. The recovery of feces and urine separately in the field of pig breeding, generates effluents having the characteristics illustrated in Table 1.
Table 1 Characteristics of the effluents after treatment of pig manure.
N-totalN-NH4 P-totalK BODY MS MS

Fces 15-30 5-15 5-15 8-20 --- --- 250-500 / k Urines 2-6 2-6 0.05- 0.5-4 1-20 1-10 5-50 1 0.2 According to FIG. 1, the preceded 10 of the present invention is realized by the steps following. When the animal produces droppings, the liquid part is treat separately of the solid fraction, and for example, as illustrated here, flows on a scupper 12 (which has a slight slope) and is directed towards a tank 14 (pre-pit) through of a pipe 16.
Preferably, the scupper 12 is placed directly under slats 18 which serve as a floor To animals. Periodically a rinsing of the scupper 12 is carried out with a fraction of liquid from a tank 20 for the purpose of cleaning and facilitating the evacuation of liquid part of the droppings and control the odors. From the tank 14 a series of treatments is carried out according to the following steps - firstly, an aerobic biological treatment by trickling bed filter sure carrier with bacteria fixed in a biotour 22 for treating simultaneously urine and stale air of the building. This treatment reduces odors effluent _7_ by nitrification-denitrification and stabilization of the fraction organic effluent.
The aerobic biological treatment makes it possible to simultaneously treat the part liquid ( urine) and the stale air of the building that is sucked under the slats and sent in the biotour 22 by a pipe 24. This principle also helps to pre-dry the feces held during their evacuation.
- secondly, a tertiary electrochemical treatment allowing completely disinfect and deodorize the liquid part and get so a liquid sleek. A treatment apparatus 26 provided with an electrochemical reactor enables to realise the purification of the polluted liquid by organic and inorganic materials dissolved or in suspension for the removal of phosphorus and heavy metals from nitrogen (TKN), for the reduction of the chemical oxygen demand (COD and DBOS) and for the destruction microorganisms according to the known art.
third, a portion of the purified liquid is directed to the reservoir for be used as a rinsing liquid for the scuppers under the slats, while than another part can be recovered for other uses (washing, irrigation, etc.) The solid part (the feces) is transported by an evacuation system of solids 28, which may for example be of the conveyor, scraper or scupper type.
V, installed under slats 18. The solid discharge system 28 allows the feces recovery separately from the urine in a reservoir 30. A ventilation system 32 provided preferably a heat recovery system 34 ensures the input fresh air outside and relatively dry in the rearing room A to reduce the odors, improve the comfort of the animals and to pre-dry the faeces during their evacuation to the tank 30. The heat recovery system 34 can be of the type exchanger heat or heat pump and carries out the transfer of available heat in the building heat released by animals for example) to the fresh air introduced from outside. The accumulated solids in the tank 30 are then directed to a system of stabilization 36 (thermal, biological or other) which makes it possible to generate a biosolid dried, deodorized and rich in fertilizer. The stabilization system uses as per example, but not limited to, the technics of static piles, windrows returned _boy Wut_ mechanically, silo corridors (automated or not), rotary drums, drying thermal, etc.
The present invention provides a novel solution for small farms not having an effluent treatment system adapted to their scale to address their environmental problems associated with the management of animal dung in a concept of "green building". Producers who favor methods of separate recovery of feces and urine can therefore benefit from such solution thanks to this invention. Indeed, although known for a long time, this approach to source separation of solid and liquid fractions from excreta did not settle environmental problems and represents high costs because it does not not reduce enough volumes to manage. The proposed invention allows this sharp reduction volumes which reduces costs by the advanced purification of the liquid fraction and rule all of the environmental problems by eliminating pathogens and odors and over there concentration of almost all the nutrients in the fraction solid.

Claims (14)

A method of treating animal manure comprising the steps of:

a) recover liquid and solid animal waste separately immediately to evacuation from a livestock building;

b) treat the recovered liquid waste by electrochemical purification of to disinfect and deodorize to obtain a purified liquid;
c) rinsing the scuppers in the livestock building to reduce spread of odors and facilitate the evacuation of faeces by recirculation of a portion of the purified liquid;
d) drying faeces up to 30% moisture content and 90%; and (e) stabilize by composting or heat treatment the dried faeces for generate a biosolids deodorized and rich in fertilizers. 2. Method according to claim 1, characterized in that it is integrated in the building breeding. 3. Method according to claim 1, characterized in that the recovery of step a) is made under the battens. 4. Method according to claim 1, characterized in that step b), electrochemical purification, is replaced by an osmosis system. 5. Method according to claim 1, characterized in that the drying of feces of step d) is performed by a direct air flow provided by a system of integrated ventilation the livestock building which also provides odor control. 6. Process according to claim 1, characterized in that the drying of feces of step d) is performed during the evacuation of faeces from the livestock building. 7. Process according to claim 6, characterized in that the drying of faeces during the evacuation of faeces from the livestock building is carried out at even a draining conveyor used to separate feces and urine under the slats. 8. The process according to claim 1, characterized in that the stabilization by composting includes a drying effect. 9. The method of claim 1, characterized in that the drying effect of the stabilization of step e) is caused by a conveyor system solid evacuation integrated into the livestock building and by heat recovery integrated into a system of ventilation which transfers the available thermal energy to the building in the air fresh introduced from the outside. 10. Process according to claim 9, characterized in that the recovery of heat is achieved by air / air exchange or heat pump. 11. Method according to claim 1, characterized in that after step e) faeces stabilized are subjected to a final thermal drying to obtain a product dry to a dryness rate varying between 50% and 90%. 12. Process according to claim 1, characterized in that a treatment organic the aerobic part of the liquid part is applied between steps a) and b) or after step b). 13. The method of claim 1, characterized in that a treatment organic aerobic of the liquid part is applied instead of step b). 14. Method according to one of claims 12 and 13, characterized in that the aerobic biological treatment in bioreactor is of biological treatment type by filter to trickling bed on fixed bacteria support for treating simultaneously the urine and the stale air of the building.