DE19652356C1 - Utilisation of animal waste as an insect growth medium - Google Patents

Abstract

Process for utilisation of animal waste to provide a raw material from which chitin/chitosan can be recovered, comprises keeping insects of the taxonomic orders Diptera (flies, gnats, midges) or Coleoptera (Beetles) in their various stages of development in contact with the animal waste in a closed reactor under such conditions as to encourage their reproduction and multiplication using the animal waste as food source for the larvae and/or imagoes, and continuously or periodically harvesting some or all of the imaginal and/or larval or other development stages and/or their pupal shells as a raw material for the extraction of chitin/chitosan.

Description

The present invention relates to a biotechnological, automated Process in a closed reactor for the recovery of animal Waste to raw material used for the production of chitin / chitosan can be used by means of feeding by insects taxonomic orders of dipteras (flies) and / or coleopteras (Beetles) in mass breeding.

It is known that for the recycling of animal waste Pressure sterilization at 133 ° C, 3 bar and a duration of 20 min (Animal Waste Ordinance and Council Directive - 90/667 / EEC). The resulting products are animal meal and fats. The Pressure sterilization is a physical process. Physical procedures can only take a lot of energy for inherent reasons operate. Energy-relevant process step according to the state In addition to the actual pressure sterilization, the technology is drying. The biotechnological processes for the recycling of animal waste requires far less energy, because it is based on enzyme-catalyzed reactions.

Chitin et al. a. in the crustacean exoskeletons (Crayfish) and insects is included. 58-85% of the dry weight of the Crustacea exoskeletons consist of chitin, 20-60% of insects (Chitin Chemistry; George A.F. Roberts; 1992; The Macmillan Press). It is also known that chitin / chitosan is made industrially Exoskeletons made by Crustacea, which is used as raw material in the processing food industry (Chitin and Chitosan; edited by Gudmund Skjak-Braek, Thorleif Anthonsen, Paul Sandford; 1989 Elsevier Science publisher; Advances in Chitin and Chitosan; edited by Charles J. Brine, Paul A. Sandford, John P. Zikakis; 1992 Elsevier Science Publishers). High manufacturing costs for out Crustacea exoskeletons are chitin / chitosan justifies that in addition to a process step of protein removal (with 0.25-2.5 M NaOH, 20-100 ° C, 1-72 h) another for the Limescale removal - CaCO₃ - (with 0.275-11 M HCl, 20 ° C, 1-48 h) necessary is (George A.F. Roberts; 1992: see above). Insect exoskeletons are in contrast  lime-free to those of crustaceans. Chitosan and other chitin derivatives arise from chemical reaction from chitin.

Bulk breeding of dipteras, in particular of Calliphorids (flesh and blow flies): 1. Process for the production of Fishing bait maggot and 2. Process for the production of imaginal, sterile Calliphorids for the biological control of those living in nature own species that cause damage in animal husbandry. In both Processes can use animal waste, but also artificial diets Mass breeding can be used. Both procedures are largely operated manually and do not take place in closed reactors (Gelled Diet for Screwworm Mass Production, D.B. Taylor, J.C. Bruce, R. Garcia, J. Econ. Entomol., Vol 84, no 3, Jun. 1991, pp. 927-935). A automated process for the production of raw material for the Obtaining chitin / chitosan by mass-growing Diptera or Coleopteren, which runs in a closed reactor, is not known.

The invention is based on two problems: 1. A method for Recovery of animal waste to indicate that with low Energy expenditure can be operated. 2. A procedure to indicate that the production of raw material for the production of chitin / chitosan by means of bulk breeding of Diptera and / or Coleoptera in one automated and closed process allowed to do so associated advantage of obtaining a lime-free raw material can.

These problems are solved by what is stated in claim 1 Procedure solved.

Animal waste is carcasses, animal parts, slaughterhouse waste and spoiled waste fleshly goods. The process is particularly suitable for recycling animal waste from mammals.

The method works in particular with flies from the Calliphoridae family (flesh and blow flies) and with beetles from the Dermestidae family (bacon and fur beetles) and their developmental stages. In addition to the adult animal - the imago - stages of development are the egg, a different number of larval stages depending on the taxonomic affiliation and the pupa. Certain types of the taxa mentioned are characterized by their larval or imaginary, sarcophagi. The animal waste is used by larvae or adults. This applies in particular to some calliphorids whose larvae completely skeletonize animal waste. After the exponential population growth begins, the population density stabilizes at a high level according to the amount of food offered. Certain calliphorid and / or Dermestidae species are preferably provided for the method, since they are also particularly suitable on account of their reproductive ability and eurythene adaptability. After animal waste has been brought into contact once with the flies / beetles or with their developmental stages in a closed reactor, the process continues independently with the constant addition of waste. If the temperature, humidity, light and / or other conditions in the closed reactor are adapted and controlled to the needs of the species used, a long-term survival and the multiplication of all development stages is possible. The process can be operated in a continuous manner if sufficient imagines, larvae and / or pupae are separated from the reactor continuously or at intervals, so that the intraspecific space and food competition is limited to a level which ensures the development of a healthy insect population . A healthy population is characterized by a high percentage of the following characteristics:
High larval and pup weight, unabridged larval and pup development, full image size and high fecundity. In the continuous mode of operation, the removal of imagines, larvae and / or pupae from the closed reactor, in addition to the waste inlet into the reactor, has a function controlling and maintaining the process. Continuous operation means that the recycling of the animal waste in the closed reactor takes place up to a finite number of reproduction cycles n, the number n being reached when a population rebuilding becomes necessary as a result of antagonist attack and / or cleaning and / or repair work /will. The method can also be operated intermittently. In this case, the adults, larvae and / or pupae are completely separated from the reactor at any time from the start of the process. In both types of process, the waste is initially inoculated with a sufficiently large number of individuals, which allows the rapid build-up of a high population density (continuous = one time, intermittent = after each separation phase). The raw material for the production of chitin / chitosan produced by the process consists of the bodies of adults, larvae, pupae and / or pupae shells.

The drawing in Fig. 1 shows the process schematically. The waste is recycled in a closed reactor (A) to prevent the escape of insect individuals. The reactor can be characterized by a hall-like character. The animal waste is recycled in it by the insects' feeding activity. Access to the reactor and its procedural, material inputs and outputs are ensured by locks, contact blocks, particle filters and other devices.

In addition to aerobic metabolism, biological implementation also includes Larvae, or larvae and adults also their intestinal microflora and other microorganisms involved. Extratestinal, microbial processes are largely aerobic under optimal process conditions.

The animal wastes are placed on one of the reactors before entering the reactor grain size adapted to the species used (for calliphorids: 50 mm) crushed using a shredder (B). The waste is from one in the reactor Conveying and turning device - roughly comparable to a Hydraulically operated snow plow - moves and to the insects Egg laying offered. Liquids resulting from the waste are e.g. B. derived by perforated or inclined conveyor tracks. Funding and Turning devices are made with the perforated or inclined Coordinated conveyor tracks in such a way that the functions promote U-turns, air supply and liquid drain are equally secured. Liquids and condensates are collected in the reactor, one thermal treatment (F) and a downstream biological Clarification (G) supplied. The water treated in this way can be released into the public Sielnetz (H) can be initiated.

The CO₂-containing exhaust air (I₁) from the reactor is by means of bio-washers, filters (J) cleaned of olfactory loads. Arrived from the bio-washer and filter the exhaust air (I₂) into the atmosphere. The inactivation of pathogens in the Exhaust air flow occurs through UV radiation and / or other electromagnetic  Energy sources (K). Which is due to the predominantly aerobic Metabolic activity of larvae, adults and microorganisms Respiratory heat generated is sufficient to heat the reactor largely from. The exhaust air is possibly exchanged with the supply air (L) (Heat exchanger = M). To maintain the reactor temperature during the winter cold period is one from the thermal Treatments (F or F and D. D see embodiment) fed Central water heating provided. The reactor temperature is above the Control circuit "exhaust air supply air heat exchanger water central heating" controlled.

The reactor is artificially lit to induce diapause prevent.

For the purpose of separating the chitin-containing raw material from the closed reactor can use the following process steps are: 1. Imaginal flies / beetles or their larvae are z. B. about Disposable traps using attractive fragrances, light and / or other effects in a collecting space separated from the reactor (N) headed. 2. Imagines, larvae, pupae and / or pupae shells sucked out of the reactor by means of a suction device (O) and into a separate collecting room (N) transported. One by the suction device (O) arising suction flow can if necessary by means of a Air classifier (P) of particles with high specific density, e.g. B. Sand to be cleaned. The insects die in the separate collecting room or are chemically and / or thermally killed.

As fragrances u. a. Anethole, octanol (1), decanol (1), pinene and Camphene used. The dead adults, dolls and / or Doll envelopes are conveyed using an aerobic (below Air supply) composting (Q), in which the inner protein-containing organs of animals are broken down by their own microflora will. In a pre / final process step for the production of the Raw materials are the before and / or after composting Imagines, their stages of development and / or their doll covers by means of a compression device (R) for the purpose of volume reduction pressed. The CO₂-containing exhaust air (I₃) of the separate collecting room and the composting is also carried out using the bio-washers and filters from relieves olfactory stress.  

The result of respiration in the reactor and as a high relative Humidity occurring water is mostly with the exhaust air over the bio-washer and the biological clarification (G).

An embodiment of the invention is described in more detail below described: Imagines by Calliphora vicina ROBINEAU-DESVOIDY (Diptera, Calliphoridae, meat and blow flies) are looking for egg laying fresh to heavily decomposed animal waste. Her female lays 540-720 Eggs directly on the trash.

The first hatches after a few hours at a temperature of 23 ° C Larval stage LS 1. The larval development at 23 ° C and 75% rel. Humidity is described in more detail below. It runs over 3 Larval stages (LS 1-3), separated by 2 molting phases can be delimited (1st molt after 18 h, 2nd molt after 42 h), and is after Completed 6-7 days (160 h) with the beginning of the doll formation (All times are calculated from the hatching of the LS 1 from the egg). The LS 1 has a length: weight ratio of shortly before the first molt 3-4 mm: 1.4 mg, the LS 2 shortly before the 2nd molt one of 10 mm: 50-60 mg. The maximum of food intake after 48 h in the LS 3 stage reached until there is an exponential increase in food intake record. The length: weight ratio of the LS 3 is 72 hours 18-22 mm: 105 mg; it no longer takes in food. After 84-96 h the LS 3 leaves the feed. Due to the development of the larval Body weight or food intake can be between a feeding and Digestion phase (up to 96 h) and a subsequent prepup phase be distinguished. After 120 h the LS 3 looks for a suitable one Pupation environment (e.g. damp sand); it now weighs 95 mg and has thus clearly compared to the time of feeding Lost weight. Also clearly differentiated from the light regime, shaded zones are accepted for pupation. During the Development from the LS 1 - shortly before the first molt - to the LS 3 to At the time of feeding, the animal takes 75 times its weight to. After about 232 h (9-10 d) the imago appears from the doll.

The Imago is a natura flower visitor and feeds on liquid, sugary foods such as nectar, pollen, honeydew or fermenting Fruit, which she soaks up with the help of her proboscis (labellum). A Reproduction occurs only when the Imago also contains protein foods  can also absorb (moist animal food).

C. vicina is characterized by maternal-induced larval diapause out. The pre-pupal larva LS 3 is diapausing just before the Formation of the doll. The LS 3 of the parents who were exposed to the short day diapause if the larval temperature is less than or equal Is 15 ° C. Were the parents exposed to the long day or is the larval one If the temperature is <15 ° C, no diapause is initiated. The critical adult The light phase is 14-15 h / 24 h at 23 ° C and 13-14 h / 24 h at 20 ° C (<Short day, <long day).

The internal organs of the adults and dolls are named after them Die within a very short time due to their own microflora largely degraded aerobically. The backlog of the fly population is that Exoskeletons of the adults and dolls.

C. vicina can be closed in the following conditions Reactor reproduced in an unlimited number of generations become: 20-25 ° C room temperature, 70-75% rel. Humidity, Light phase: dark phase 16: 8 h, 2-5 air changes / h. With rising temperature shortens the development time of the fly, however microbial processes are also increasing. Because especially anaerobic Processes with their metabolites NH₃ / NH₄ and H₂S largely must be suppressed, the process is more likely to lower Temperatures set within the 20-25 ° C range. The relative Humidity should not exceed 75% to allow the wing to unfold Imago after their appearance from the doll not to be affected. The approximately natural photoperiod of 16: 8 h supports the natural activity rhythm of the insects and effectively prevents Diapause induction. The 2-5 times air change / h is necessary to suppress anaerobic microbial processes and promote aerobic.

The LS 3 becomes pupated in shaded areas given. The dolls / doll covers can be removed from these zones be sucked off.

In the process, the imagines are offered a diluted sugar solution on leaked areas. Skeletal bone fragments are freed from adhering larvae on a vibrating sieve - directly above the waste entrance of the reactor ( Fig. 1, B) - ground using a hammer mill ( Fig. 1, C) and subjected to a thermal aftertreatment ( Fig. 1, D). If post-treatment combustion is used, the residual material can be used as an inorganic fertilizer ( Fig. 1, E). When using bone-free, horn-free, claw-free and hoof-free slaughter waste such as offal, the procedure can be simplified by the latter steps C, D and E.

Claims (13)

1. A process for recycling animal waste to raw material for the production of chitin / chitosan, characterized in that insects of the taxonomic orders Diptera and / or Coleoptera or their developmental stages on animal waste are kept in a closed reactor under conditions which ensure permanent survival and enable the insects and all their developmental stages to multiply by utilizing the animal waste by feeding through their larvae and / or imagines, and continuously or at intervals, the imaginal dipteras and / or coleopteras and / or their developmental stages and / or their pupae shells in whole or in part are separated as raw material for the production of chitin / chitosan from the closed reactor. 2. The method according to claim 1, characterized, that in particular species of the taxonomic families Calliphoridae (Meat and blow flies) and / or Dermestidae (bacon and Fur beetles) can be used. 3. The method according to claim 1 or 2, characterized, that the temperature, humidity, light and / or other Conditions in the closed reactor meet the needs of the used species are adapted and controlled. 4. The method according to any one of the preceding claims, characterized, that means the animal waste in the closed reactor automatic conveying, turning and ventilation devices treated will. 5. The method according to any one of the preceding claims,  characterized, that the larvae of Diptera and / or Coleoptera by means of shaded areas and / or sand pits the opportunity to Pupation is given. 6. The method according to any one of the preceding claims, characterized, that means exciters in exhaust air streams from the closed reactor UV or other electromagnetic radiation can be deactivated. 7. The method according to any one of the preceding claims, characterized, that imaginary diptera and / or coleoptera and / or their larvae for the purpose of separation from the closed reactor by means of attractive looking fragrances, light and / or other effects in one separate collection room. 8. The method according to claims 1-6, characterized, that imaginary diptera and / or coleoptera and / or their larvae and / or their dolls and / or their doll covers for the purpose a separation from the closed reactor by means of a Suction devices are transported to a separate collecting room. 9. The method according to any one of the preceding claims, characterized, that a suction flow created by the suction device by means of a Air classifier is cleaned of particles, their specific Density higher than the specific density of the insects or their Stages of development or their doll shells. 10. The method according to any one of the preceding claims, characterized, that the separated imaginal dipteras and / or coleopteras and / or  their separate stages of development in the separate Die collecting room and / or chemically and / or thermally to Be brought to die. 11. The method according to claim 10, characterized, that dead imaginary dipteras and / or coleopteras and / or the development stages of which are composted under air supply. 12. The method according to any one of the preceding claims, characterized, that imaginary dipteras and / or coleopteras and / or their Stages of development and / or their doll shells before and / or after composting for volume reduction by means of a Compression device can be pressed. 13. The method according to claims 1-9, characterized, that the recycling of animal waste in the closed reactor in continuous operation takes place.