Animal husbandry – Confining or housing – Permanent building
Reexamination Certificate
2001-04-06
2004-03-02
Poon, Peter M. (Department: 3643)
Animal husbandry
Confining or housing
Permanent building
C119S450000
Reexamination Certificate
active
06698383
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method for removing excrement, made up of feces and urine, of animals kept in a stall, in particular pigs. In addition, the invention relates to an apparatus for executing the method.
In wide use in practice, and therefore generally known, are stalls whose floor surface is constructed so as to be entirely or partially permeable to excrement, for example as a slatted floor, a liquid manure channel for the collection and common drainage of feces and urine being provided under the permeable floor. The liquid manure channel has a relatively large capacity, because it is used not only to collect but also to store feces and urine, i.e., liquid manure. From time to time the liquid manure channel is emptied, whereby the liquid manure is then pumped either into a liquid manure container outside the stall or into a transport vehicle so that it can be applied on a field surface. Significant environmental pollution, due to the formation and diffusion of ammonia and methane gas, disadvantageously arises both in the stall during the collection and storing of the liquid manure and also in the surroundings of the liquid manure container, or in the surroundings of a field surface dunged with liquid manure. In particular, unpleasant odors arise that are felt by most of those affected to be strongly disturbing, and that also have an adverse effect on the health of the animals kept in the stall. In order to avoid damage to the animals kept in the stall, an intensive exchange of air is required, which takes place using ventilators, for which a considerable amount of electrical energy must be used. However, this intensive air exchange again results in an increased discharge of harmful gas outside the stall.
A partial reduction of the disadvantages stated above, in particular in the interior of the stall, can be achieved by mechanical cleaning apparatuses, such as those known for example from DE 43 12 128 A1 or from DE 21 27 370 A1. Using these known cleaning apparatuses, feces and urine are transported together from a deposition surface into a liquid manure collection region, so that a reduced degree of pollution is achieved inside the stall. However, here as well the environmental pollution outside the stall, due to liquid manure stored in a container and due to liquid manure applied on field surfaces as dung, occurs to an unreduced extent.
From DD-PS 21 15 96, a method is known for the fractional mechanical drainage of liquid manure in animal stalls, in particular for calf stalls. This method is characterized in that the following are preferably combined: a perforated floor extending over as much of the overall space occupied by the animals as possible, a large portion of said floor being occupied by holes, and a fecal surface, inclined transverse to the row of standing animals and having a conduit for urine and having a blade that is divided into sections and that has a slow advance rate, as well as having separate dumping pits for the solid and the liquid phase at the end of the row of standing animals, with connection to separate supply containers. Beyond the separate carrying off and storage of feces and urine, however, this prior art does not supply any indication as to whether and in what way a further treatment of feces and/or urine is to take place.
SUMMARY OF THE INVENTION
The object of the present invention is therefore to create a method and an apparatus for the execution of the method of the type named above that avoid the stated disadvantages and with which an improved—in particular, more environmentally friendly and less harmful to animals—disposal of the excrement is achieved.
With respect to the method, the object is achieved by a method of the type named above that is characterized in that the carrying off of feces and urine from the stall and the storing and/or further treatment thereof takes place in a fresh state, before the beginning of a decomposition, and in that the further treatment of the feces comprises at least the following steps:
a surface enlargement of the fresh feces, and
a drying of the feces to a moisture content that prevents a decomposition.
It is essential to the invention that feces and urine are carried off from the stall not only separately from one another but also in a still-fresh state, before the beginning of a decomposition, so that in the stall no stress due to excrement stored there and deposited there for a longer period, and the decomposition products thereof, can occur. In addition, it is provided according to the invention that the further treatment of the feces comprises at least the two described steps. The further treatment serves first of all to prevent the feces from developing environmentally harmful properties as a result of decomposition, and in addition to make the feces profitably recoverable. Since, due to the separation from the urine, the fresh feces conveyed out of the stall already has a relatively low moisture content, and because according to the invention a surface enlargement of the feces is carried out, for example using a vibrating apparatus or a perforated plate, with the inventive method it is possible for the first time to dry the feces with a reasonable energy expense. The drying temperature can thereby be relatively low, so that it is possible to use waste heat for the drying; moreover, the drying temperature should remain below 60° C., in order to avoid an undesirable decomposition caused by temperature. In its dried state, the feces can be stored and transported, because, due to the lack of liquid in the feces, no bacterial decomposition can take place, and because it is then also hardly possible any longer for unpleasant odors to arise.
After being removed from the stall, the urine does not absolutely have to be further treated, because between 85 and 99% of all nutrients and salts remain in the solid material, i.e., in the feces. For this reason, the urine can and may be applied directly onto farming surfaces, or may be drained off as sewage.
With the inventive method, a drastic reduction of the ammonia content in the stall air is achieved, so that the ventilation inside the stall can be correspondingly reduced. Moreover, the harmful formation of methane gas in the stall is precluded. The number of germs in the stall air is drastically reduced, because, due to the separate carrying off of feces and urine in a fresh state, no bacterial decomposition can occur inside the stall. In contrast to liquid manure, the carried-off urine does not decompose, because the bacteria still contained in the urine are not presented with a sufficient quantity of nutrients. For this reason, a conversion of the urea contained in the urine into ammonia can no longer occur.
The further treatment of the feces and, if necessary, of the urine can take place with a delay, including intermediate storage, or can take place immediately. The choice here is made in particular according to the quantities of urine and feces that occur and are to be treated, and also according to whether the respective apparatus for further treatment is better operated continuously or in charge-by-charge fashion.
A preferred development of the method provides that the drying of the feces takes place at first only until a moisture content between approximately 10 and 25 weight % has been reached, and that the feces is then pressed, with further reduction of moisture, to form pressed pieces having a residual moisture content that prevents a decomposition. The pressing of the feces to form pressed pieces necessarily results in a reduction in moisture, because the pressure exerted presses out a large part of the previously contained moisture, without its being necessary to provide a separate drying step for this purpose. The previous drying can therefore be limited to the indicated incomplete drying, which limits the expense for the previous drying, in particular the energy expense. Moreover, in comparison with dried feces in powdered form, the feces pressed to form pressed pieces is easy to handle and can be
Terwort Roland
Wettendorf Christoph
Olszewski Joan M.
Poon Peter M.
Sonnenschein Nath & Rosenthal
Wettendorf Christoph
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