FI124320B - Method and equipment for treating slurry - Google Patents

Description

FIELD OF THE INVENTION

The invention relates to the field of agricultural technology and separation technology. More particularly, the invention relates to the treatment of animal slurry by separation techniques.

Background of the Invention

Modern milk production and animal husbandry are highly concentrated. In connection with this, the scale of the livestock farms is increasing, resulting in the production of large amounts of slurry locally. A large amount of sludge causes logistical problems because the manure has to be spread over a large field area in a short period of time. In this case, the manure has to be transported over long distances, which entails costs. In addition, significant investment is needed in the distribution vessel. As livestock farms grow, it is increasingly important to improve the efficiency of sludge handling. The current sludge tanks have a size of about 1000-8 15 000 m3, which means that there is a great need for sludge compaction.

The spreading of slurry on fields is currently limited by its high phosphorus content. Thus, for ecological reasons, there is a need to develop sludge treatment in order to utilize sludge manure and its valuable components more efficiently.

20 Farm-scale Membrane Filtration of Sow Slurry, J. Agric.

Engng. Res. (1999) 73, 403-409. J. G. Pieters et al., Describe a method of treating pig manure by microfiltration and reverse osmosis. The manure is first allowed to settle for three days, whereupon the solid settles to the bottom of the silo. The liquid portion of the slurry is then separated and the liquid is passed through microfiltration and reverse osmosis twice,

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BRIEF DESCRIPTION OF THE INVENTION A process for the treatment of animal slurry has now been invented, which enables a more efficient utilization of the whole slurry.

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“On its farm. The method effectively controls the local environmental load of slurry manure and places the slurry in fractions of optimal composition for use as a nutrient mixture. The process according to the invention enables the new utilization of animal slurry and its components. The process enables all sludge manure to be treated and the nutrients and trace elements contained therein to be effectively separated into different fractions, in particular phosphorus, nitrogen and calcium. The fractions can be further utilized in an appropriate manner, allowing optimal use of nutrients, thereby reducing the risk of nutrient leaching.

The idea of the invention is to compact slurry manure in such a way that the transport of the liquid, i.e. water, is significantly reduced, thereby reducing transport costs and reducing the risk of field compaction. By the method of the invention, expanding farms do not need to extend the storage of slurry as the space requirement of the slurry is reduced. Slurry spreading is also accelerated because a larger amount of slurry manure can be spread on the same Levi fleet. With the compacted lie-10 roller, the economic spreading distance of the slurry increases, which facilitates the growth of the farms in this respect.

One aspect of the invention is a process for treating a substantially animal slurry, the method comprising the steps of: - substantially slurrying the animal slurry, - mixing the slurry to obtain a substantially homogeneous slurry, MF) to obtain a solid-20 MF retentate and an MF permeate substantially free of insoluble solids, - concentrating the MF permeate by reverse osmosis (RO) to obtain a first RO retentate and a first RO permeate.

Another aspect of the invention is the use of the MF retentate obtained by the process of the invention as a nutrient mixture.

Yet another aspect of the invention is the use of one or more RO retentates or mixtures thereof obtained in the process of the invention.

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^ use as a nutrient mixture.

Another aspect of the invention is a nutrient composition comprising

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MF retentate obtained in the process of the invention.

| Another aspect of the invention is an apparatus for treating animal slurry comprising: g - a mixing unit for slurry mixing - a microfiltration unit for separating solids from slurry 3 - 35 - to concentrate at least one reverse osmosis unit.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates an embodiment of the method of the present invention and outlines the process steps;

Figure 2 illustrates an embodiment of the process of the invention and recycling of the fractions obtained in the process;

Fig. 3 illustrates an embodiment of the method of the invention and combining the fractions provided by the method; Figure 4 illustrates an embodiment of the apparatus according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

One aspect of the invention is a process for treating a substantially animal slurry comprising the steps of: - substantially slurrying the animal slurry, 15 - mixing the slurry to obtain a substantially homogeneous slurry, ) to obtain a solid-containing MF retentate and an MF permeate substantially free of 20 insoluble solids, - concentrating the MF-permeate by reverse osmosis (RO) to obtain the first RO retentate and the first RO permeate.

The term '' substantially animal slurry 'as used herein means that animal slurry consists essentially of animal? 25 slurry, but may also include, for example, a livestock kitchen / milk room

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rinsing and / or washing water for dairy installations and / or rinsing and / or washing floors.

§ Animal slurry can be any animal slurry, g Typically slurry is cattle or pig slurry.

Q_ 30 The slurry is treated in the process of the invention in the form of slurry

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£ 5 at natural temperature. If desired, the method of the invention may

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c \ j includes a heating or cooling step at any stage of the process.

Prior to separating the slurry manure, the slurry is mixed to treat the slurry in its entirety according to the invention. For mixing the slurry manure, any mixer can be used which mixes the slurry into 4 uniform masses which can be pumped further to the next treatment step.

The mixed slurry mass is separated to separate the coarse solid from the liquid fraction. For separation, any means can be used to effect separation. Separation can be accomplished, for example, by sieving, centrifuging, centrifuging, screening with or without pressure, or by mechanical separators such as a drum filter, a screw separator or a plate filter. Separation can also be accomplished by squeezing the slurry through a gauze. Separation yields about 15-40% solid dry manure 10 of the slurry mass. The dry matter of the separated manure is typically at least about 15%. Most of the phosphorus, potassium and other minerals in the slurry remain in the dry matter.

If desired, separation can be enhanced by washing, whereby the transfer of soluble solids to the liquid fraction is enhanced. The liquid fractions obtained in the subsequent step of the process of the invention can be used for washing. Separation aids may be used to enhance the separation of solids and / or minerals and / or nutrients.

The liquid fraction from the separation is then passed to microfiltration (MF) to separate the solid contained in the liquid fraction, which is not removed by the separator, into the MF retentate. The microfiltration membrane may be, for example, a hollow fiber or ceramic film, a plate filter, a tubular module or a metal screen and having a pore size of about 0.02 to 10 µm. MF retentate is comprised of about 15-40% of the initial slurry amount and typically has a dry solids content of more than 2%. The MF retentate can be used as such in a nutrient mixture or mixed with another nutrient mixture. The MF retentate can also be returned to the separator. MF permeate contains most of the slurry nitrogen. MF permeate is essentially free of insoluble solids.

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Microfiltration typically uses a concentration factor of 2 to 10. In one embodiment, the concentration factor is 2-5.

30 MF permeate is concentrated by reverse osmosis (RO). RO- | the concentrate or retentate typically has a solids content of more than 1.5%. The RO retentate ci contains a significant proportion of the nitrogen contained in the manure and can be used as such or mixed with another nutrient mixture, n RO retentate is suitable as a nutrient mixture for plants, for example during the growing season. The RO retentate can also be returned to the separator. The permeate obtained in reverse osmosis is almost pure water and does not contain significant amounts of phosphorus or other nutrients. RO permeate can be impregnated, for example, in the field or elsewhere on the ground.

The RO permeate obtained from the first concentration of MF permeate may, if desired, be re-concentrated by reverse osmosis to enhance purification of the first en-5 permeate. Another RO-permeate is obtained which is of such a pure composition that it can generally be released into the environment. Reverse osmosis can be repeated several times to enhance purification, whereupon the permeate obtained in the previous step is introduced into reverse osmosis. In one embodiment of the invention, reverse-theosmosis is performed twice. In another embodiment of the invention, reverse osmosis is performed three times.

The permeate obtained in one or more reverse osmosis may be partially or completely recycled to the microfiltration feed and / or separator to enhance separation of soluble solids.

The RO retentates obtained in one or more reverse osmosis can be used as a nutrient mixture as such or mixed with another nutrient mixture. RO retentates may also be combined with each other and / or with the MF retentate. The retentates can be further returned to the slurry for washing purposes.

To reduce odor nuisances, acids such as nitric acid or hydrochloric acid, or bases such as sodium hydroxide or potassium hydroxide may be added to the liquid fraction. The acid or base may be added before or after the microfiltration step or after the reverse osmosis step. By adjusting the pH with the aid of an acid or a base, the evaporation of odorous substances can be affected.

By means of the method according to the invention, the slurry can be divided into different fractions, for example as follows: 10,000 m3 of slurry is formed by milling 2,000-3,500 m of dry manure. The MF-concentrated liquid fraction ° generates 2,000-4,500 m3 and the water absorbed in reverse osmosis ° 30 2,000-6,000 m The total amount of manure applied to the fields is 4,000- | 8,000 m3, which corresponds to 40-80% of the initial volume. The figures are indicative and vary with the characteristics of the slurry and filtration objectives.

Figures 1-3 illustrate certain embodiments of the process of the invention. Optional actions are indicated by a dashed line.

Figure 1 outlines the steps of the method according to the invention. The slurry is mixed and the mixed slurry is led to a separation to give 6 a dry fraction and a liquid fraction. The liquid fraction is microfiltrated (MF) to give MF retentate and MF permeate. The MF permeate is concentrated by reverse osmosis (RO). The resulting permeate (RO-permeate I) can be further concentrated one or more times by reverse osmosis, whereupon the permeate obtained in reverse osmosis is introduced into the concentrate-5. Figure 1 illustrates two optional reverse osmosis steps. There may be more than one of these steps if desired.

Figure 2 illustrates the process of the invention in a process for recycling the fractions obtained at various stages. One or more permeate obtained in reverse osmosis 10 may be returned to the microfiltration feed and / or separator for enhanced solids separation. One or more retentates obtained by reverse osmosis can be returned to the slurry manure and / or separator to enhance nutrient separation. The MF retentate can be recovered for separation to enhance separation of insoluble solid 15. Similarly, RO permeate / permeate can be returned to separation for enhanced nitrogen separation.

Figure 3 illustrates the combining of fractions obtained at various stages of the process of the invention into a nutrient mixture. One or more retents obtained in reverse osmosis may be combined with one another or with the MF-20 retentate. The dry fraction from the separation can be combined with the MF retentate.

The method of the invention may be carried out batchwise or continuously.

The fractions obtained in the process of the invention can be combined in the desired manner into preparations having the desired composition with regard to nutrients. The obtained fractions can also be used as a nutrient mixture as such, o In particular, the dry fraction obtained during separation may be used as a nutrient mixture,

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^ as a soil conditioner, as a source of energy or for composting. MF retentate may also be used as such or combined with one or more ° 30 RO retentates. The fractions may also be supplemented with non-native | wool with nutrients. The resulting RO permeate (s) are pure water that can be released into the environment or used, for example, as irrigation water.

Another aspect of the invention is the use of the MF retentate obtained in the process of the invention as a nutrient mixture.

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Another aspect of the invention is the use of one or more RO retentates or a mixture thereof obtained in the process of the invention as a nutrient mixture.

Another aspect of the invention is a nutrient mixture containing 5 MF retentate obtained by the process of the invention.

Another aspect of the invention is a nutrient composition comprising one or more RO retentates or mixtures thereof obtained by the process of the invention and / or one or more RO retentates obtained by the process of the invention and additionally MF retentate obtained by the process of the invention. In one embodiment of the invention, the N: P ratio of the nutrient mixture is 99: 1-28: 100.

Another aspect of the invention is an apparatus for treating animal slurry comprising: - a mixing unit for mixing the slurry 15 - a microfiltration unit for separating solids from the slurry liquid fraction - for concentrating at least one reverse osmosis unit liquid fraction.

The apparatus according to the invention is illustrated in Figure 4. The optional operations 20 are indicated by a dashed line. According to the figure, the apparatus comprises at least one reverse osmosis unit. In one embodiment, the apparatus comprises two reverse osmosis units. In another embodiment, the apparatus comprises three reverse osmosis units. The apparatus also comprises a mixing unit for mixing the slurry. The apparatus may comprise a separating unit for separating the solid fraction of slurry-manure from the liquid fraction prior to feeding the slurry to a microfiltration unit.

5 The hardware may be fixed or mobile

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^ on a surface, for example on wheels. In one embodiment, the apparatus is on a movable platform. The advantage of mobile equipment is that it can be

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° 30 easily moves from farm to farm, reducing the need to build permanent slurries I make processing equipment for farms. In addition, the mobile equipment may be energy self-sufficient. Mobile equipment thus provides a cost-effective and ecological alternative.

The apparatus according to the invention is suitable for

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^ 35 to implement this method.

For example, the unit may have an hourly output of 100 m3 / h.

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The following examples are provided to further illustrate but not limit the invention.

eXAMPLES

Example 1. Slurry Pretreatment 5 The slurry was mixed in a slurry tank on the farm with a slurry mixer.

About 100 kg of slurry manure was separated to separate the solid by squeezing the slurry through a gauze cloth. Separation was done in several batches, whereby the solids remaining on the gauze fabric were scraped off before the sludge was added to the fabric. Separation was performed at the native temperature of the slurry. Experiments were performed separately on 10 cattle and pig slurries. Bovine manure was separated by a concentration factor (CF) of 3.9 and pork manure by a factor of 2.9. The resulting solid and liquid fractions were collected. The amount of raw material and fractions generated were weighed and a bulk sample was taken.

The analytical results and the number of fractions are given in Table 1.

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Table 1. Compositions and masses of bovine and pig slurry and separated fractions __ mass ash K__P__N k-a __ kg __% mg / kg mg / kg%%

Bovine slurry separation, CF = 3.9_

Cattle 89 89 1.83 5000 1000 0.20 6.45

Dry fraction 22.7 6.06 14000 3200 0.21 17.98

Liquid fraction 66.3 0.38 1900 310 0.20 2.52 111 1 11 o Pig slurry separation, CF = 2.9 cd Pig slurry 84.2 5.03 5500 6100 0.48 7.97 o ------ -

Dry fraction 29.3 12.6 12000 16000 0.45 17.40 o

Nestejae 54.9 0.99 2000 750 0.50 2.94 cc

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In addition, the distribution of the components into liquid and solid fractions and their content in the dry matter were calculated. The results are shown in Table 2.

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Table 2. Bovine and porcine slurry, dry matter and water content of fractions separated from it, composition of dry matter and distribution of various components into fractions __ ash__K__P__N k-a water __% __ g / kg g / kg% __ kg kg

Bovine Honey Separation, CF = 3.9_

Cattle 28.3 77 16 3 5.75 83.2

Dry fraction__33.7 78__18 1__4.08 18.6

Nestejae__15.1 75__12 8__1.67 64.6

Proportion of dry 84.5 71.6 77.9 26.6 71.0 25.5 in fraction (¾) _______

Proportion of liquid 15.5 28.4 22.1 73.4 29.0 74.5 in fraction (¾) ______

Pig slurry separation, CF = 2.9_

Piglet 63.1 69 77 6.0 6.7 77.5

Dry fraction 72.4 69 92 2.6 5.1 24.2

Nestejae__33.7 68__26 16.9 1.6 53.3

Proportion of dry 87.2 75.9 91.3 32.6 76.0 31.2 in fraction (%) _______

Proportion of liquid 12.8 23.7 8.0 67.5 24.1 68.8 in fraction (%) ______ 5

The results show that most of the sludge solids, phosphorus, potassium and other minerals remain in the dry fraction. Instead, the majority of g nitrogen ends up in the liquid fraction.

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o Example 2. Microfiltration of Liquid Fraction The liquid fractions of bovine and porcine slurry isolated in Example 1 were subjected to microfiltration (Koch Romicon, HF 5.0-52-MF, Koch Membrane Sys-

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terns, Wilmington, USA) on a test scale. The liquid fraction of bovine slurry was concentrated by a factor of 2.2 and the pig slurry by a factor of 3.0.

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The microfiltration fractions and ° 15 masses of bovine and porcine slurry are shown in Table 3.

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Table 3. Composition of fractions obtained by microfiltration of the separated liquid fraction of bovine and porcine slurry

Microfiltration of Bovine Slurry Liquid, CF = 2.2_ MF Feed__66.3 0.38 1900 310 0.20 2.52 MF Retentate 30.8 0.55 2100 550 0.28 4.09 10 ------- MF Permeate 35.5 0.35 1734 39 0.11 | 1.14

Microfiltration of Pig Slurry Based Liquid, CF = 3.0_ MF Feed__54.9 0.99 2000 750 0.50 2.94 MF Retentate 18.6 1.55 2300 1800 0.69 6.22 15 MF Permeate 36.34 0 , 71 2200 160 0.35 0.85

On the basis of the analysis results, the dry substance composition of the fractions and the amount of dry matter and water in the various fractions were calculated. It was also calculated how much of the slurry components ended up in each fraction. The results 20 are shown in Table 4.

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Table 4. Amount of dry matter in the microfiltration fraction of the separated liquid fraction of bovine and pig slurry, dry matter composition and proportion of different components in the fraction from the original sludge __ ash K__P__N k-a water __% __ g / kg g / kg% kg kg

Microfiltration of Bovine Slurry Liquid, CF = 2.2_ MF Feed__15.1 75 12 8 1.67 64.6 MF Retentate 13.4 51__13 7__1.26 29.5 MF Permeate 30.5 153 3__10 0.40 35.1

Proportion of MF- 15.5 28.4 22.1 73.4 29.0 74.5 in Feed (%) _______

Proportion of MF-10.4 14.6 18.2 46.6 21.9 34.6 in retentate (%) _______

Proportion MF 7.6 13.9 1.5 22.2 7.0 39.9 permeate (%) _______

Microfiltration of Pig Slurry Based Liquid, CF = 3.0_ MF Feed__33.7 68 26 16.9 1.6 53.3 MF Retentate 24.9 37 29 11.1 1.2 17.4 MF Permeate 83.5 259 19 41.7 0.3 36.0

Share 12.8 23.7 8.0 67.5 24.1 68.8 in MF Feed (%) _______

Percentage of MF retention 6.8 9.2 6.5 31.7 17.2 22.5 guarantees (%) _______

Proportion of MF permeate 6.1 17.3 1.1 31.8 4.6 46.5% (%)

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CO 5 ° The results show that the liquid fraction of the slurry for concentration is indicated

° to a much more compact form such that the MF retentate remained at almost all input P

| and a significant portion of the N contained in the feed. More than half of the water was transferred to the permeate.

Example 3. Filtration of MF permeate by reverse osmosis (RO) o cm The microfiltration permeate fractionated from bovine and porcine manure in Example 2 was concentrated by reverse osmosis (RO) at a concentration factor of 5.6 and 3.7 (film: Koch HR 2540). Filtration yielded two fractions, RO-retentate I and RO-permeate I.

RO-permeate I was repeatedly filtered by reverse osmosis on the same membrane, again yielding two fractions, RO-retentate II and RO-5-permeate II. For bovine slurry, a second RO filtration was performed with a concentration factor of 11.3 and for pig slurry a factor of 12.7. The amounts and compositions of the fractions obtained are shown in Table 5.

Table 5. Compositions of Filtration Fractions of Bovine and Pig Slurry Based MF Permeate RO-10 __ Mass Ash K__P__N__k ^ a_ __kg __% __ mg / kg mg / kg% __% _

RO Filtration of Bovine Slurry Based Liquid, RO I CF = 5.6 and RO II CF = 11.3 RO Feed__35.5 0.35 1734 39 0.11 1.14_ RO-reten- 6.1 1.85 7800 55 0.39 3.78at I_______ RO-perm 29.4 <0.15 <10 <10 0.01 0.08at I_______ RO-reten 2.6 0.51 2300 <10 0.13 0.88at II_______ RO -perme- 26.8 <0.15 <10 <10 0.00 0.01 aate II _____ | ___ | _

RO filtration of pig slurry based liquid, RO I CF = 3.7 and RO II CF = 12.7 RO feed__36.34 0.71 2200 160 0.35 0.85_ ^ RO retention 9.64 1.64 6300 250 0.92 2.98

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co o RO-perm- ^ 26.7 <0.15 770 16 0.14 0.39 oat I_______ 5 RO-reten- 2.1 0.35 1400 79 0.21 0.62

dated II

(AJ ------- o RO-perm- £ 24.6 <0.15 <10 <10 0.00 0.04

™ Agate II

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On the basis of the analysis results, the dry substance composition of the fractions and the amount of dry matter and water in the various fractions were calculated. It was also calculated how much of the slurry components ended up in each fraction. The results are shown in Table 6.

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Table 6. Dry solids composition, dry solids and water content of fractions of bovine and porcine slurry MF permeate in the fractions and proportion of various components in the fractions from the original sludge

RO Filtration of Bovine Slurry Based Liquid, RO I CF = 5.6 and RO II CF = 11.3 RO Feed 30.5 153 3 10 0.40 35.13_ RO Retent 0.23 5.89at I__48.9 206 1__10___ RO-perm 0.02 29.39 ac I_____13___ RO-reten 0.02 2.59 ac II__58.0 261___15___ RO-perm 0.00 26.80 ac II_____42___

Share in RO feed (%) __ 7.6 13.9 1.5 22.2 7.0 39.9_

Proportion RO- ^ retentate J _ (%) __ 7.0 10.8 0.4 13.0 4.0 6.9_ o Proportion RO-2 permeate x I (%) _____ 1.7 0.4 33.0_

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Proportion RO

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^ retentate ^ Il (%) __ 0.8 1.4 ___ 1.8 0.4 2.9_ ^ Proportion RO-permeate

Il (%) 0.6 0.0 30.1-14

RO filtration of pig slurry based fluid, RO I CF = 3.7 and RO II CF = 12.7_ RO feed 83.5 259 19 41.7 0.3 36.0_ RO re t 55.0 211 8 30, 9 0.3 9.4 baht I_______ RO perm 197.4 36.9 0.1 26.6 baht I_______ RO perm 56.5 226 13 34.5 0.0 2.1 baht II_______ RO perm - 9.6 0.0 24.6 ages II_______

Share of RO feed 6.1 17.3 1.1 31.8 4.6 46.5 jobs (%) _______

Proportion of RO-reten 3.7 13.1 0.5 22.0 4.3 12.1 acetate I (%) _______

Proportion RO- 0.0 4.4 0.1 9.5 1.6 34.3 Acetate I (%) _______

Proportion of RO-reten 0.2 0.6 0.0 1.1 0.2 2.7 taatate II (%) _______

Proportion of RO-permeate 0.2 0.1 31.7 acres II (%) _______ 'ί ο ™ The results show that RO-permeate I and II end up with a significant proportion of the slurry water but with a very small proportion of N and P. :from. In practice, the resulting water is thus very pure.

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Example 5 Tables 7 and 8 summarize the composition data and characteristics related to slurry fractionation based on Examples 1-3. From the table it can be seen that the process according to the invention allows the separation of fractions of slurry having very different nitrogen, phosphorus and potassium contents and interrelationships compared to the original slurry.

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Table 7. Composition of fractions fractionated from bovine slurry, as well as nutrient ratios and material balances RO-__ slurry-dry fraction MF retentate RO retentates permeate N (g / kg) 2.0 2.1__2JJ__3J__0.0 P (g / kg) 1.0 3, 2__0 ^ 6__0,0__ K (g / kg) 5.0 14.0 2,1__M__ N: P: K__25: 13: 63 11:17:72 51: 10: 39__33: 0: 66__ N-share 100 27__47__15__1_ P- share__100__78__18__0__ K-share__100 72__15__12__ dry matter 6.45__18,0__4jJ__2 / 9__0.01_capacity__100__71__22__4__0_ water content 94__82 __% __ 97__100_ water content__100__22__35__10__32_ 5 't δ c \ ji

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Table 8. Composition of fractions fractionated from pork slurry, and nutrient ratios and material balances___ RO slurry__dry fraction MF retentate RO retentates permeate N (g / kg) __ 4 ^ 8__4 ^ 5__M__7j9__M_ P (g / kg) 6.1__IM__M__M ) 5.5__IM__M__M__ N: P: K__29: 37: 34 14:49:37 63: 16: 21__58: 2: 40__ P-share__100__33__32__23__0_ P-share__M __? 1__7__0__ K-share__M__76__9__14__ dry matter 7.97__17.4__M__M__0.04_ ka- share 100__76__17__4__0_ water content 92__83__94__97__100_ water share__100__31__22__15__32_

Example 5

The slurry was treated in a similar manner as in Example 1 except that the separation was carried out on industrial scale, instead of on the gauze, using separators. Mechanical separators were tested. All devices provided a liquid portion which was filtered according to Examples 2-3. The composition results of the obtained fractions were similar to those in Examples 2-4.

Example 6

The fractions obtained by the process of the invention are formulated with a nutrient mixture having the desired composition. Table 9 shows two different

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^ Law of nutrient composition.

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Table 9 __recipe 1 recipe 2 __% _

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Dry fraction___17_ MF feed ___ MF retentate__78__54_ MF permeate ___ RO retentate I__16__25_ RO permeate I___ RO retentate II__30__30_ RO permeate II __

Composition of nutrient mixtures __ Ash Na K Ca Mg Cl PN Water __g / kg g / kg g / kg g / kg g / kg g / kg g / kg g / kg% _ recipe 1 195.5 13 78 12 8 24 11 73.8 96.17 Recipe 2,301.2 | 11 95 17 10 27 13 49.0 94.82 5 It will be obvious to one skilled in the art that as technology advances, the basic idea of the invention can be implemented in many different ways. The invention and its embodiments are thus not limited to the examples described above, but may vary within the scope of the claims.

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Claims (20)

A process for treating a substantially animal slurry, comprising the steps of: 5. substantially slurrying the animal slurry, - mixing the slurry to obtain a substantially homogeneous slurry, - applying a homogeneous slurry to a separator to obtain a dry fraction and a liquid fraction, to obtain a solid-containing MF retentate and MF permeate, - concentrating the MF permeate by reverse osmosis (RO) to obtain the first RO retentate and the first RO permeate. The method of claim 1, wherein the microfiltration is carried out at a film size of 0.02 to 10 µm. The method according to claim 1 or 2, wherein the microfiltration is carried out at a concentration factor of 2 to 10, preferably 2 to 5. The method according to any one of the preceding claims, wherein the MF retentate is returned to the separator. The method of any one of the preceding claims, wherein the first RO permeate is introduced into a second reverse osmosis to provide a second RO retentate and a second RO permeate. The method of claim 5, wherein the second RO permeate is introduced into a third reverse osmosis to provide a third RO retentate and a third RO permeate. The method according to any one of the preceding claims, wherein the first, second and / or third RO retentates are returned to the slurry CD 9 and / or separator. The method according to any one of the preceding claims, wherein the first, second and / or third RO permeate is returned to the liquid distribution CL and / or the separator. A method according to any one of the preceding claims, wherein the slurry is bovine or porcine slurry, The method of any one of claims 6 to 9, wherein the first, second and / or third RO retentates are combined to provide a nutrient mixture. The method of any one of claims 1 to 9, wherein the first, second and / or third RO retentates are combined with the MF retentate to obtain a nutrient mixture. Use of the MF retentate 5 obtained in any one of claims 1 to 4 as a nutrient mixture. Use of one or more RO retentates obtained in any one of claims 1 to 8 as a nutrient mixture. A nutrient mixture comprising the MF retentate obtained by the process of any one of claims 1 to 4 and wherein the N / P ratio is 3.8 to 6.7. The nutrient mixture of claim 14, wherein the K / N ratio is 1.1 to 1.9. Apparatus for treating animal slurry comprising: - a mixing unit for mixing the slurry 15. a microfiltration unit for separating solids from the slurry liquid fraction - for concentrating at least one reverse osmosis unit liquid fraction. The apparatus of claim 16, comprising two 20 reverse osmosis units. The apparatus of claim 16, comprising three reverse osmosis units. Apparatus according to any one of claims 16 to 18, comprising a separating unit for separating the slurry of solid slurry from the liquid fraction. Apparatus according to any one of claims 16 to 19, mounted on a movable platform, for example on wheels, δ C \ J i CD O o X CC CL C i O CD CM O CM