DE2163364A1 - Method and device for converting animal waste products into a nutritious feed additive with a high protein content - Google Patents

Description

Dr.-lng. E. BERKENFELD · Dipl.-Ing. H. BESKENFELD, patent attorneys, Cologne Attachment file number

to enter »20. ΒθΖβΠΛβΓ 1971 VA // Name d. Note INTERNATIONAL FARM

SYSTEMS, INC.

Method and device for the conversion of animal waste products into a nutritious, high protein feed additive

The invention relates to a method and a device for the transformation of animal waste products in a nutritious feed additive with high protein content _o the invention relates in particular to a method and a device for the transformation of animal waste products in a product with high protein content, which is then the grain meal feed of the animal can be added as a nutritious feed additive.

The invention provides a useful solution to two critical problems in the rearing of animals such as pigs for human consumption. The first problem arises from the disposal of animal waste in order to eliminate and effectively minimize the risk of contamination of the water supply by animal waste waters. Most ecologists have forgotten the extent of current animal pollution in view of the current excitement about industrial pollution. However, a study by the American Society of Agricultural Engineers concluded that the production of sewage from animals in the United States is equivalent to the sewage produced by a billion people. "For example, there are about a hundred million pigs in the United States States, each of which generates wastewater daily that can be equated to 2.5 to 3 people. There are also roughly fifty million cattle, each of which produces sewage every day that can be equated to 10 to 14 people. These generate waste

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no problems if they are spread evenly across the country. However, the current trend in animal rearing is more and directed more towards cordoned off systems in which the animals are raised and fattened within a restricted environment until they are ripe for slaughter. In these restricted rearing facilities, the animals are usually in a minimum space trapped on concrete floors. The feed must be supplied and the waste products must be disposed of by the same are discharged, or by disposal in a wastewater treatment plant. It is the elimination of these waste products which is one of the most serious restrictions on mass rearing of animals in a restricted environment.

Many methods are currently in use to dispose of the animal waste products, most of them causing some form of water pollution. The waste is drained from cattle pastures on mountain slopes, or it is simply washed away by the rain. Some farmers build large artificial ponds or basins, or use natural ponds. They dispose of the animal waste products by dumping them into these ponds. This process creates large, smelly basins which attract flies and mosquitoes. Some farmers even built pastures near open pit shafts so that the waste could be pumped directly into the ground. These waste disposal methods create pollution that may seep into the water supply. In other cases, many farmers still drive the collected waste back to the land, as they did before the cordoned-off systems were in place. But even if a third of livestock farmers removed the waste instead of driving it back to the country, the amount of raw sewage going into the water supply would still be enormous, _{or the like}

Currently about 30 to 40 % of the people bred in this country are

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ended pigs reared in isolated systems and the conversion into cordoned-off systems for pig rearing is accelerated Ten years ago few, if any, completely cordoned Schweinezüchteinrichtungen available, but their number is continuously increasing _o With the continuous increase in the number of these facilities is in In a few years the growing effect of disposing of the litter of one hundred million pigs or more raised annually has revealed a pollution problem of considerable magnitude.

This problem is even more emphasized when it is taken into account that until a few years ago most of the agricultural waste was brought back into the country in the form of fertilizers to help enrich the land's crops. But with increasing economic pressure to raise cattle near the wholesale markets, this traditional cycle is being changed. Now a growing percentage of pigs and most poultry spend all or most of their lives in the barriers of a pasture or poultry house, mostly on the outskirts of a large city. Because of the transportation and labor costs associated with collecting, drying, and processing manure into a useful fertilizer, farmers now prefer the cheap, concentrated and easy-to-use man-made fertilizers. The result is that the outskirts of a number of large cities have ever-growing dung heaps with flies, drainage problems and the risk of increasing air and water pollution. Since the invention provides a convenient and economical process to all the animals in a sealed-off system to eliminate waste products generated, this problem is eliminated the V contaminating action of animal waste products

A second useful incidental circumstance of the method and the device according to the invention is an increased economic

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Yield from raising pigs in a fenced-off environment. The circulation of all animal waste products, in addition to eliminating undesirable air and water pollution effects, also increases the economic effectiveness of pig rearing. The cost of feed for pigs represents approximately 70 to 75 % of the expenditure for pig breeding. The feed rations for pigs consist mainly of corn as a concentrate and soybean meal as an added protein. The soybean meal represents about 11 to 22% by weight of the pig's feed ration, depending on the age and weight of the animal, and 20 to 36 % of the total feed costs is replaced. In addition, there is no need for expensive sewage and waste treatment plants _{or the like}

The method and the device according to the invention are also easily suitable for automation, so that a typical locked animal shelter, as described in the American patent application No. ₀ 879 o 194 of November 24, 1969, can be looked after and maintained by a single person can. One person can therefore easily care for up to five thousand pigs housed in a building described in the aforementioned application using the method and apparatus according to the invention for converting the animal waste products into a very nutritious, high protein feed additive.

Accordingly, it is an object of the invention to provide a method and an apparatus for converting animals Waste products in a * nutritious, high protein feed additive.

Another object of the invention is to provide a method for converting animal waste products into one nutritious and disease-free feed additive with a high

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teemalt.

Yet another object of the invention is to provide a method and apparatus for converting animal animals Waste products from an aerobic process into a feed additive for pigs.

Another object of the invention is to form a device for stirring and aerating a lot of materials such as animal waste products to stimulate the conversion thereof into a product having a high protein content, the mixed feed ration of the animal as a feed additive examples ( can be.

Yet another object of the invention is to provide a method and apparatus for economical Elimination of animal waste products produced by animals raised in an enclosed area, to eliminate air and water pollution associated with the disposal of such waste.

The invention therefore relates to a method for converting animal waste into a nutritious feed additive with a high protein content for animals. The invention is particularly directed to a similar method of treating the slurry from a Oxydationsgraben or a slurry of untreated animal excreta by a process which comprises stirring and aeration. The temperature and pH of the slurry can be monitored and, optionally, a yeast containing product can be used to start the process. The animal feed additive in this process can also be heated to an elevated temperature in order to render intestinal bacteria ineffective and to improve the digestibility of the product.

These and other features and advantages of the invention will emerge

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from the following description with reference to the drawings.

Fig. 1 shows a perspective view with parts broken away a preferred embodiment of the device according to the invention.

Figures 2-4 are graphical representations of the number of organisms in a treated slurry of waste of pigs as a function of the heating of the treated slurry to various elevated temperatures in minutes.

According to the preferred embodiment of the invention, solid and liquid waste material from animals such as pigs, which are housed in a closed environment, collected in a processing vessel or drum. The drum is provided with facilities for venting and stirring the contents. The drum is supplied with an amount of water by one Forming slurry from water and the animal waste products. Initially, a culture of pure yeast can also be used, for example Candida utilis, can be added to start the conversion process. In addition, the slurry can optionally contain a small amount of sugar can be added to produce enough raw materials or vaccines for the process. Then it will be Air is pumped through the drum by means of the aerator and the slurry is agitated to begin a process, which converts the nitrogen in animal waste products to a high protein product which is significantly increased Contains amounts of amino acids while urea is essentially eliminated from the treated slurry. the Conversion is very effective and the high protein product that is taken out of the drum can be added to the grain meal feed of the animal can be admixed directly as a feed additive. Some of the product can be left in the drum to order

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the transformation process of the next batch of animal waste products and to start water supplied to the drum.

The processing device 10 shown in FIG. 1 consists of a vessel or a storage drum 12 into which the solid and liquid waste products from animals, for example pigs, are pumped to stir and aerate a slurry of water and animal waste products. The agitator includes a pair of agitating blades 18 and 20, each of which consists of a peripheral frame i 22, mounted within which a provided with an open latticework wall 24, as for example, expanded metal, cut preferably of a material. Each of the blades 18 and 20 is rigidly mounted along a horizontal central portion thereof on a central shaft 26 which extends generally in the axial direction of the drum 12.

The shaft 26 is a cylindrical shaft which extends above the open upper end 28 of the vessel 12 and on the end of which a pulley 30 is attached. The lower end 32 of the shaft 26 is supported by a pivot bearing part 34, which is attached to the top of the ventilation device 16 ™ so that the shaft 26 can rotate when the pulley 30 is rotated to rotate the impellers 18 and 20 move, the shaft 26 is at the open upper end 28 of the jar 12 stored within a bearing part 36 which is attached to a transverse arm 38, the ends 40 and 42 of which in the vicinity of the open upper end 28 connected to the inside of the vessel 12 are.

A motor 44 is arranged on a support member 46 which is rigidly attached at 48 to the outside of the vessel 12. On the

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Output shaft 50 of motor 44 is attached to a pulley 52, which is coupled to the pulley 30 by a drive belt 54. The motor 44 therefore drives the shaft and the paddles 18, 20 on.

Inside the cylindrical shaft 26 is an air supply line 56 arranged concentrically, which passes through an opening 58 in the center of the pulley 30. The top end the air supply line 56 is operatively connected to an air compressor 60 and its lower end 62 is connected to the ventilation device 16 in connection. The air supply line 56 fe is at a distance from the inner wall of the shaft 26 and rotates not when the shaft 26 is rotated.

The ventilation device 16 consists of a central distributor 64, which is connected to the lower end 62 of the air supply line 56. From the manifold 64 go several tubular Parts 66, each of which is on the top with air outlet openings 68 and is provided with end caps 70. The compressed air from the compressor 60 therefore flows through the air supply line 56 into the distributor 64 and then through the air outlet openings 68 of the tubular parts 66 into the lower part of the vessel 12 " The ventilation device 16 is correspondingly supported on the base plate 72 of the vessel 12 by a support 74.

In operation there is a slurry of water and animal waste products introduced into the vessel 12 to a height which is at least above the upper edge of the blades 18,20. The motor 44 is then actuated which rotates the paddles 18, 20 to stir the slurry. The air compressor 60 is started, pushing compressed air through the air supply line 56 and out of the air outlet openings 68, to distribute air in vessel 12 within the slurry. Since the blades 18, 20 wall surfaces 24 with an open latticework the slurry flows through the wall

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while it is being stirred. The ones from the air vents 68 in the ventilation device 16 below the show fine upward flowing air flow is split up to the To effectively distribute air in the slurry, as will be further described below. In addition, the air flow in Air bubbles split up, which are more easily dispersed in the slurry and mixed with it, in order to achieve the chemical conversion to support the animal waste products in the nutritious feed additive with high protein content in an advantageous manner, as will be described in more detail below.

EXAMPLE

According to one embodiment of the method according to the invention, a slurry of animal waste was introduced into the vessel 12 in the ratio of about 4.53 liters of liquid to 0.453 kg of solid waste material. The liquid contained approximately 1.8 liters of the pig liquid waste and approximately 2.7 liters of added water. The vessel had a capacity of approximately 207.9 liters and approximately 132.3 liters of slurry was introduced. To set the conversion process at the beginning of a cycle in motion, the vessel were in 0.24 1 of a culture pure yeast Candida utilis and 0.24 1 baker's yeast, in aqueous solu- ä solution of approximately 25% dry yeast, and introduced 2.265 kg sugar . The compressor 60 was started and operated at full capacity g, which could supply air under the usual pressures and temperatures at the rate of 100 l / min. The agitator 14 was operated at 50 rpm to effectively break down the solid particles in the slurry and to keep the particles in solution. In larger units, the speed would be lower in order to obtain a comparable peak speed of the stirring device. As already mentioned, the air exiting from the air outlet openings 68 is also caused by the rotation of the stirring device at a high speed

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Flow split into smaller air bubbles, which are easier to distribute in the solution. The solution was then heated to a temperature of about 32 ° - 3 ° C, for example, held by a heater, which temperature-dependent by a (not shown) heating element is controlled, and the pH of the solution was checked periodically. Corresponding temperatures can be approximately 24 to 38 ° C., for example approximately 24 to 35 ° C. For the most useful conversion of animal waste products by the process of the invention, it has been found that a pH of 4.5-5 is most effective in creating the best possible environment for the growth of the yeast culture while the aerobic growth is in progress Bacteria is delayed. However, the pH range can extend from 4 to 7, for example from 4 to 6.5. Accordingly, depending on the pH reading, phosphoric acid is periodically added if necessary to maintain the pH of the solution in the preferred range of 4.5-5. However, hydrochloric acid or other inorganic acids can also be used.

While the device according to the invention supplies compressed atmospheric air to the fermentation vessel, it goes without saying the oxygen in the air, which reacts to aid in the conversion of animal waste products. The more Oxygen can be rapidly added to the slurry in vessel 12, the faster the conversion will occur. It is therefore important adding oxygen to the slurry and keeping the oxygen in solution to enable the conversion of the waste products. As already mentioned, the rotating show fine 18, 20 split the air flow into fine air bubbles, which can be more easily distributed throughout the slurry and which has a larger contact surface between the oxygen in the air bubbles and the waste products in the solution. These air bubbles stay in the solution longer because of the whirling motion created by the blades.

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The process according to the invention results in the production of a considerable amount of heat and of carbon dioxide _p which can be discharged into the atmosphere or collected _o Depending on the ambient conditions, the above-mentioned heating device may therefore not be required for some months of the year in order to maintain the desired operating temperatures obtain.

It has been found that there is a metabolic process in this environment is going on through which animal waste products to a very significant extent «· aerobically into a useful product being transformed.

Of course, the feed additive with a high protein content can be produced by a batch process, i.e. no addition or removal until complete conversion, or by a continuous process in which part of the product is removed and raw animal waste is added at periodic intervals. In an embodiment of the invention according to the above method, after a treatment period of three days, approximately 9.45 of the converted product was removed for each of the two daily feed rations of the pigs and approximately 9 _and 45 liters of a slurry of the pig waste products was added immediately thereafter. The slurry of waste products was essentially the same as that described above and contained an average of about 10 to 13 wt% solids. It was found that the 9.45 liters of the newly added animal waste products in the mixing vessel of 207.9 liters were completely assimilated and sufficiently converted so that within twelve hours, the interval between feedings, approximately 9.45 liters Feed additives containing an average of about 10 to 13 wt .-? 6 solids were removed from the jar. The product withdrawn from the jar was entirely and directly used as a feed additive as described below.

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In a procedure using five test pigs and five control pigs, the five test pigs were fed a combination of corn and bean meal in a slurry with the high protein yeast product resulting from the processing of animal waste products in the above-described manner revealed. The five control pigs were fed the same combination of corn and bean meal slurried in water without the high protein feed additive. Each group of pigs had additional drinking water available. The control group of pigs was given a feed ration of 85 % corn, 10 % bean meal and 5 % vitamins and minerals. For the control group, the total dry feed was approximately 9 kg per day. Since the pigs were fed in a group, the amount eaten by each was variable according to their habits. The test group of pigs was fed the same amount of the feed ration, which for the test group was supplemented per day by approximately 18.9 liters of the high-protein feed additive, which was made up of a solution of approximately 12% by weight of the dry product and the Remaining liquid existed. The animal waste products for this process were obtained from several pigs, each of which produced approximately 0.453 kg of solid waste and approximately four times the amount of liquid waste to which water was added. This waste was used to produce nearly the same amount of feed additive through the process described above. The pigs in each group had the weight gain shown in Table I when fed on the schedule given above for two months.

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- 13 TABLE I.

Group of
Control
pigs Initial weight Increasing weight A. 32.66 kg 18.14 kg B. 33.56 kg 12.70 kg C. 34.47 kg 28.12 kg D. 36.28 kg 16.78 kg Ξ 38.10 kg 28.12 kg total weight increased ί 102.86 kg Group of
Attempt
pigs Initial weight Weight would increase F. 30.84 kg 27.21 kg G 33.56 kg 28.12 kg H 34.43 kg 28.57 kg I. 36.28 kg 31.29 kg J 39.00 kg 30.39 kg total weight gain 145.58 kg

A statistical analysis of the test results can be shown it is clear that there is a considerable difference between the two groups with a 95% certainty is by adding the group of test pigs that was fed with the usual feed ration, supplemented by the feed additive with high protein content from the converted animal waste, showed significant weight gain. Accordingly, by this process of converting animal waste into a feed additive produces a product of considerable nutritional value.

As a general indication of the production of amino acids in the process of promoting the growth of useful products The organic waste products from pig manure is transferred to the

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Reference is made to Table II below which compares the amino acid content in raw solid pig manure and in a sample of the product · of the semi-continuous process ζθΐφ described above. Although the amino acid content can vary, the following numbers provide an indication of the nutritional value of the product produced by the process according to the invention. The amino acid content is the nutritional value of the product and is useful for supplying the necessary for the growth of the animal protein "When analyzing the converted product contained no detectable amount of urea _o

TABLE II

Amino acid content in percent by weight of the solid amino acid

% in raw % in the vice Pig manure changed product 0.15 1.03 0.03 0.36 0.08 0.91 0.20 1.51 0.11 0.82 0.13 0.98 0.18 1.16 0.12 0.88 not determined 0.34 0.10 0.75 0.18 1.44 0.09 0.63 0.14 0.83 not determined 0.10

Histidine

Arginine

Aspartic acid

Proline

Glycine

Alamin

Methionine

Isoleucine

Leucine

Tryosin

Phenylalin

Tryptophan

EXAMPLE II

In another embodiment of the invention, the

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■ - 15 -

Slurried product of a conventionally operated oxidation ditch used to be a feed additive for pigs
produce. The oxidation ditch consists of a continuous open channel, which is shaped like a raceway and provided with a ventilation rotor. Above the oxidation ditch
Pig pens are built with slotted floors above the ditch. The liquid and solid waste together with the draining drinking water result in the waste solution. «The rotor in the trench keeps the contents in circulation, at least at a surface speed of 30 cm per second, in order to prevent product sludge from settling. The vortex action of the rotor mixes air into the slurry of waste products. The oxidation ditch is mainly used as a means of disposing of the pig waste, the product of the ditch
is usually pumped into tailings ponds, for example.

The liquid obtained from the oxidation ditch in this example had a solids content of 1 to 2 %. The solids content of the product from the oxidation trench was maintained by monitoring the amount of runoff entering the trench. The product of the oxidation ditch
was pumped to a stainless steel container from 1,200 1 up to about two thirds of its capacity, as well stirred and ventilated at a minimum temperature of 29 C. A thermostatically controlled heating mantle was activated when the \ temperature below 29 ° C decreased, "The aeration was sufficient
to create a bubble effect. When the aeration was stopped, the oxygen level was approximately 3.5 parts per one
Million. The agitator in the container was designed like a propeller and was operated to maintain a thorough mixing effect. Air was drawn through the bottom of the container
• a hose fed, which was provided with holes at its lower end parallel to the bottom of the container. Air was pumped at a rate sufficient to produce a
cause copious blistering _o

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After about a week of continued aeration and stirring at 29 ° C or more up to about 33 ° C, the resulting product was fed to a group of pigs. About 20 % of the product from the container was fed to the pigs every day (two daily rations of about 10 % each) and a quantity of the product from the oxidation ditch was added to the container once a day in order to keep the container filled up to two thirds of its capacity. A group of 40 pigs with an initial age of 78 days and an average initial weight of 34 kg were fed a regular ration for a period of 84 days.

The basic ration consisted of:

component

percent

Corn 89.4 soybean meal 8.0

Calcium carbonate 1.0

Dicalcium phosphate 1.0

Mineral salt traces 0.5

Procin-vitamin mix 0.1

100.0

™ All pigs were fed from troughs in groups of "ten, and an attempt was made to keep the daily feed intake similar. Groups A and B were given the basic ration fed, with 2.2 parts of the modified product poured from the oxidation ditch over each part of the basic ration which was produced in the manner described above »Groups C and D were fed the basic ration over which 2.2 parts of water were poured for each part of the basic ration. A summary of the results is as follows:

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Average daily gain (kg)

Gain / feed (kg / kg)

average daily feed (kg)

group

0.49 0.268

1.85

average additional solids per pig (kg) 0.04

0.50
0.260

group
CD

0.45 0.46 0.234 0.244

1.93

1.91

The results show that the modified product from the oxidation ditch reduced feed per 0.453 kg of gain. At the same time, the process had the beneficial effect of eliminating some of an otherwise troublesome waste.

In studies with rats, it was found that 10 to 50 % of the normal protein content of a normal ration could be replaced by a modified product from the oxidation ditch without any detrimental effect on the growth of the rats. For pigs, about 10 to 25 % of the normal protein content of a normal ration should preferably be replaced by the modified product from the oxidation ditch.

The advantage of aerobically nourished products over fresh manure is that the amino acid concentration is higher. Corn contains only 0.25 % lysine, while aerobically fed manure contains 1.00 to 1.25% lysine or larger amounts _e

The slurry from the oxidation ditch can be concentrated to a concentration of about 5 to 15 % solids prior to the treatment described in this example by conventional methods such as centrifugation.

From this it can be seen that in addition to training a method and apparatus for disposing of animal waste products in a clean and efficient manner to remove any

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To avoid contaminating effects of the disposal of animal waste, the invention also provides a method and an apparatus for converting animal waste products into a nutritious, high protein feed additive which is a remarkable one Shows ability to provide nutritional value for pigs.

An initiator can be added to the animal waste. In Example II, an initiator was not used, but could be added ₀ An initiator preferably isb containing yeast a substance that occurs naturally or in animal feed products, such as corn. The above process is preferably carried out with the yeast Candida utilis, either alone or with additional yeasts to start fermentation of the pig waste. Other yeasts can be used with or in place of Candida utilis. The amount of yeast used to start the process can be varied and this amount is primarily of importance in determining the time required to achieve stable conditions.

The yeasts that have the greatest potential utility are those commonly referred to as sugar fermenting yeasts which also have the property of assimilating nitrogen from urea. Examples of these yeasts are those that ™ may be referred to as Saccharomyce or Torula, as in American Patent 3o105o799 is indicated.

Once the conversion process is started, the process can be carried out by the batch method, continuously or semi-continuously by adding pig waste, if desired with water, and a removed feed additive fed directly to the animals. Although the solid product produced by this process is separated from the slurry and can be fed to the animals, an advantage of this process is that the sludge discharged directly can be used as animal feed. The amount of used

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Water can be varied widely to create an easy-to-handle animal waste product slurry that can be introduced into the process. The input slurry preferably contains 1 to 25 % solid waste. The animal waste products themselves can be used as an input slurry if sufficient liquid animal waste is available. Other ingredients can be added during the process to supplement the beneficial products discharged, such as minerals that the animals are commonly fed and those commonly used in fermentation processes, an inorganic nitrogen source such as ammonia ^ and additional sources of organic materials, such as corn ₀

Substantial ventilation is required for the apparently metabolic processes of the microbiological organisms that develop or lead to the conversion of manure into useful feed additive for pigs. The ventilation should be upright can be obtained to prevent the relapse of the growth of the anaerobic bacteria. Ventilation below those specified calm test conditions results in a substantial visible bubble effect and a dissolved oxygen content of 3 to 4 parts per million has been found to be satisfactory. The correct supply of oxygen can also can be calculated from published sources in the field of microbial conversion, such as the growth of Yeast in industrial waste. The amount of air used can also be changed to a large extent. Among the specified Conditions, the rate is preferably about 50 to 120 liters per minute. The theoretical requirements for fermentations are less, but an excess is used because the oxygen in the slurry is not completely absorbed will. Expressed in relation to the product produced, 28,800 liters of air were added per 0.453 kilograms of the product " The standard of essential ventilation includes thorough

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Aeration of a substantial portion of the pig waste slurry in contrast to the oxidation ditch, in which the ventilation takes place mainly in the vicinity of the rotor.

The stirring should be sufficient to stir the constituents of the process keep in a thoroughly mixed condition. In addition, the stirring device supports the splitting and distribution of the Air bubbles introduced into the bottom of the container below the agitator, as well as the dissolution and use of oxygen in the process «During the conversion process, aeration and stirring can be applied continuously or intermittently during the processing period with only short intervals of interruption.

In both of the described embodiments of the invention, the processing conditions produce a feed additive which contains substantial amounts of amino acids and proteins. The protein content of raw pig manure is approximately 15 to 20 %. The process according to the invention converts the pig manure into a feed additive with a higher protein content containing approximately 20 to 40% protein. The products of this process were analyzed and found to contain no detectable amount of urea, indicating the conversion of a simple, non-nutritious nitrogen component to a useful protein. These products also contain increased amounts of important amino acids, such as about 1 to 2 % lysine and about 0.1 % tryptophan.

As indicated above, the converted pig manure can contain approximately 20% of the total dry feed for an animal, although larger or smaller amounts can be used. The product according to the invention is particularly useful as a substitute for or a supplement to the usual high protein animal feed, such as soybean meal.

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216336A

EXAMPLE III

In one embodiment of the invention, the animal waste product slurry treated by the method described above in Example I is further processed in a separate container at an elevated temperature. This further treatment is, in part, a sterilization process to reduce the intestinal bacteria and coli bacteria content of the treated slurry and to improve the digestibility of the product. It is known that living yeasts and other cultured organisms are less easily digested because of their tough outer cell walls than when they are killed and their ( cell walls have ruptured.) This process makes the inner cellular protoplasm accessible to digestion without first having the tough cell wall has to be broken down or digested.

Three groups of samples were taken from this slurry and heated to 60, 71 and 82 ° C. The samples were taken after they had been heated for 1, 5, 10, 20 and 30 minutes. Thermal killing curves for the intestinal bacteria were recorded for each of the three heating temperatures. These curves are shown in FIGS. For the same a strong decrease of the existing Coli bacteria and intestinal bacteria is within the first five minutes of heating, etc. to each of the three temperatures shown. During this time interval it appears that some of the protein is coagulated, which could explain the sharp drop in the slope of the curve at 60 ° C after this initial heating period. The initially coagulated protein forms a protective coating that enables the organisms to survive the subsequent heat treatment.

A significant number of intestinal bacteria survived heating to 71 ° C for thirty minutes. The coli bacteria in the samples, on the other hand, were able to heat up to 71 ° C for more not survive than ten minutes.

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The intestinal bacteria and coli bacteria were greatly reduced after five minutes of heating at 82 ° C. No surviving coli bacteria were found after ten minutes of heating, and all intestinal bacteria were effectively killed after thirty minutes of heating at 82 ° C. From these curves it can be seen that a sufficient monitoring of the coliform bacteria and the intestinal bacteria is preferably carried out by heating the liquid in the vessel to a temperature of 71 C for 4 or twenty minutes at 82 ° C for ten minutes. To eliminate all intestinal bacteria, heating to a temperature of 82 ° C for thirty minutes is suitable. The feed additive is therefore preferably subjected to a temperature of at least 60 ° C for at least five minutes. When the temperature rises, the ineffectiveness of the intestinal bacteria increases, while all remaining organisms are destroyed at about 82 ° C in about thirty minutes. As the temperature rises further, for example to 93 C, the time required for the treatment to achieve comparable results is reduced. Higher temperatures can also be used to further reduce treatment time, in conjunction with increased pressure in a conventional pressure cooker. Another alternative is to pressurize a container containing the treated slurry and then quickly release the pressure. The strong pressure reduction will support the rupture of the cell walls and the destruction of living organisms. As mentioned above, this improves the digestibility and sterilization of the product. This process can be carried out with a conventional -F device designed for this purpose. Pressurization and depressurization can be done with steam or the like.

From this it can be seen that in addition to training a method and apparatus for disposing of animal waste products in a clean and efficient manner to remove any

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To avoid the contaminating effects of animal waste disposal, the invention also provides a method and apparatus for converting animal waste products into a nutritious, high protein feed additive which exhibits a remarkable ability to provide nutritional value to pigs and eliminate potential disease-causing microorganisms. Although the invention has been illustrated by the conversion of pig waste, other animal waste can also be used and the products produced can be fed to pigs or other domestic animals such as non-ruminant animals _{or the like}

patent claims ι

209829/0591

Claims (19)

Dr.-1 ng. E. BERKENFELD · Dipl.-Ing. H. BERKENFELD, patent attorneys, Cologne Attachment file number to the entry from December 20, 1971 VA // Name d. Note INTERNATIONAL FARM SYSTEMS, INC. PATENT CLAIMS 1. Method of treating animal slurry Waste products characterized by substantial aeration of the slurry at an elevated temperature to a To set the conversion process in motion for the purpose of forming a feed additive for animals. 2. The method according to claim 1, characterized in that the slurry during the conversion process on a Temperature of 24 to 35 C is maintained. 3. The method according to claims 1 and 2, characterized in that the slurry during the conversion process is maintained at a pH of about 4 to 6.5. 4. The method according to claim 3, characterized in that the slurry an inorganic acid, such as Phosphoric acid, is added to maintain the slurry at this pH. 5. The method according to claims 1 to 4, characterized in that the conversion process by the addition of yeast and sugar is set in motion to the waste products. 6. The method according to claim 5, characterized in that the yeast is of the type Candida utilis. 7. 'Method according to claims 1 to 6, characterized in that that the process is carried out in a container, where- 209829/0591 with part of the product of the process periodically out of the container removed and a similar amount of the waste product is introduced into the container. S. The method according to claims 1 to 7> characterized in that that the slurry is agitated during the conversion process. 9. The method according to claims 1 to 8, characterized in that the aeration and agitation of the slurry therein there is that pressurized, oxygen-containing gas in the slurry distributed and the gas split into bubbles ι to thereby keep the gas bubbles in the slurry in solution. 10. The method according to claims 1 to 9, characterized in that that the conversion process reduces the amino acid content of the waste products elevated. 11. The method according to claims 1 to 10, characterized in that that the conversion process essentially eliminates urea from the waste products. 12. The method according to claims 1 to 11, characterized in that that the product of the conversion process to a temperature of more than 60 ° C for a sufficient period of time is heated to inactivate a substantial portion of the intestinal bacteria in the slurry. 13. The method according to claim 12, characterized in that the temperature is at least about 71 C for a period of time to about 20 minutes in order to substantially all coli bacteria ineffective in the slurry. 14. The method according to claim 12, characterized in that 209829/0591 the temperature is at least about 82 ° C for a period of up to about 30 minutes in order to substantially all of the intestinal bacteria ineffective in the slurry. 15. The method according to claims 1 to 14, characterized in that that pig waste products are used. 16. The method according to claims 1 to 15, characterized in that that the product of the transformation process is fed to pigs. P. 17. Device for aerating and stirring a slurry of liquid and solid waste, characterized through a container to hold the slurry, by means of a device which supplies pressurized gas to the container, by means of a device arranged in the container for stirring the slurry, wherein the agitator is adjusted so that the gas is distributed in the container as gas bubbles within the slurry in order to keep the gas bubbles in solution and enlarge them Provide a contact surface between the gas and the slurry, and wherein the agitation means includes at least one open latticework wall, one with the slurry having in contact surface, as well as means operatively connected to the same, which the wall in the The slurry is rotated to thereby stir the slurry as the slurry passes through the wall surface. 18. The device according to claim 17, characterized in that that the agitator also has a Jiohle central shaft which extends into the container with the wall disposed on the shaft, as well I 49/1 209829/0 591 means coupling the shaft to the motor so that when the motor is actuated, the shaft and the wall rotate be moved. 19. The device according to claim 17, characterized in that that the device which supplies gas under pressure to the container consists of a gas compressor, one Feed line from the compressor passes through the central shaft and communicates with a gas outlet device in the container stands, that the gas outlet device consists of a distributor which is in communication with the compressor and with several radial ones Gas discharge elements are provided, that each element has openings to allow jets of gas to exit into the slurry in the container, and that the agitator is arranged elevated above the elements is so that the rotating wall distributes the gas jets as gas bubbles in the slurry. 209829/0591