COMPOSTING APPARATUS FOR ORGANIC WASTE

Abstract: The invention relates to an apparatus for composting organic waste, which apparatus includes a biofilter unit (2) and a composter unit (3) and which is provided with a common feed point (1) and a common intermediate bottom (16). In accordance with the invention, the mixing of the biofilter unit (2) and the composter unit (3) is carried out by means of a common mixer equipment (4a, 4b) and the intermediate bottom (16) is, below the feed point (1), provided with a drop hatch (8), whereby the waste can be directed to separate units.

Description: COMPOSTING APPARATUS FOR ORGANIC WASTE The present invention relates to an apparatus for composting organic waste in a combined reactor arrangement, where the waste can, without burdening the environment, be processed in a closed system. The apparatus combines the processing unit proper, i.e. the composter, and the exhaust gas clean¬ ing unit, i.e. the biofilter, to a uniform structure, which leads to remarkable operational and economical advantages. Composting as such is a well-known method for treating organic waste, and so is the use of a biofilter for treating composting air as well as air in general. However, these facilities have always been used separately, so that they have not formed a single apparatus with operational unity. As aerobic processes, composting and biofiltering are both based on the behaviour of similar microbes. Composting is generally realized by means of either drum composters, where the aerating is done by turning the mass every once in a while by rotating the drum, or by upright composters, where air is pressed into the mass in order to render the mass in an aerobic state. In upright composters, the mixing of the mass is often carried out by means of blades or conveyors, for instance. In order to intesify the composting process, in the compost mass there is often added some already composted mass, or a mass return system is arranged in the composter. Often the employed biofilter is an unmixed vessel or upright column filled with composted mass. The filling agent can also be bark or peat, where the biological process is most often started directly without purposely added microbe stocks. While applying composting in the treatment of waste material together with biofiltering, it was surprisingly found out that by combining these reactors to a functional unity, remarkable advantages are achieved; the machinery is simplified, the operation is intensified and the feed system of the waste materials and biofilter masses is simplified. By using biofilter mass as the microbe stock for composting, there is simultaneously achieved the advantage that a sepa¬ rate microbe supply arrangement (addition of compost mass/mass return conveyor) becomes unnecessary. By means of the present invention, a distinctively more economical system is achieved. According to the invention, there is formed an apparatus where by using the same feed conveyor, the waste is conveyed both to the composter unit and to the biofilter unit, either to the same or adjacent feed locations. According to the invention, the biofilter unit forms the top part of the apparatus, and the composter unit forms the bottom part. From the composter part, the air is blown into the biofilter mass, wherefro it is after cleaning, discharged to the environment. The mass first entering the biofilter unit is then discharged to the composter unit, where it simultane¬ ously serves as the composting microbe inoculant, thus intensifying the composting process. In the biofilter unit, a longer delay time can be applied than in the composter unit, so that the mass discharged to composting particularly intensifies the composting process. In the biofilter part of the apparatus of the invention, there can be used peat, park, waste etc. Because the delay time in the biofilter unit can be longer than in the com¬ poster unit, the waste can also form the filler mass of the biofilter unit, because at that stage the waste already has been fully composted, i.e. has become odorless mass. This leads to the advantage that it is not necessary to sepa¬ rately purchase pure mass, peat etc. to the apparatus. In the apparatus of the invention, the biofilter and the composter have a common mixer shaft system, and a common motor/machinery that rotates the mixer shaft system. The ceiling of the composter unit is the bottom of the biofilter unit, so that this advantageous structure both simplifies the apparatus and makes it more economical. In the apparatus of the invention, below the feed point of the mass/masses there is arranged a drop hatch, wherefrom the mass to be composted can be fed through the biofilter unit. While opening the intermediate hatch, from the biofilter there is simultaneously discharged some mass that improves the operation of the composter. The biofilter mass can be discharged at other points, too, to the composter through the drop hatches. To the biofilter unit of the biofilter-composter apparatus, there can be fed an amount of 1 t/d waste peat, and to the composter unit 20 t/d. In the biofilter unit, the mass delay time can advantageously be 15 d, and in the composter unit 3 d. By means of this arrangement, there is obtained fully composted mass directly from the biofilter to the composter unit, so that the operation of the ' composter is intensified. By using the biofilter mass as a microbe stock, the separate step of adding composted mass or returning some compost mass is thus eliminated. The air discharged from the composter, which air as such generally spreads unpleasant odors to the surroundings, is in the apparatus of the invention pressed into the biofilter mass. If the biofilter mass is particularly loose, the air can be conducted directly, through the holes in the inter¬ mediate bottom, to the biofilter mass. Figure 1 describes a biofilter-composter of the invention in a cross-sectional illustration and schematical representation. Figure 2 describes another preferred embodiment of the biofilter-composter of the invention in a cross- sectional illustration and schematical representa¬ tion. According to figure 1, the waste and the biofilter mass are fed by the feed conveyor (15) to the feed funnel (1), where¬ from it, depending on the open/closed position of the drop hatch (8) goes either to the biofilter (2) or to the com¬ poster (3) . The biofilter and the composter are mixed by intermediation of the same mixer machinery (4b) and mixer shaft system (4a) . The mixer shaft system (4a) is advanta¬ geously supported by means of a bottom support (10) and a top support (11) . In the apparatus of the invention, mixing is advantageously carried out by means of mixer blades (5) . The compost air is pressed into the apparatus through a blower/compressor (13) , and from the composter unit (3) it is shifted to the biofilter unit (2) through another blower/compressor (14) . The cleaned air is discharged from the apparatus through the discharge pipe (6) . The feed fun¬ nel (1) can be provided with a closing hatch (7) , whereby the exhaust air can be conducted to the discharg "pipe (6). Biofilter mass can also be discharged through the drop hatch (9) to the composter. From the composter unit, mass is advantageously discharged through the drop hatch (12) . The intermediate bottom (16) between the biofilter unit (2) and the composter unit (3) can advantageously be perforated, in which case the blower (14) becomes unnecessary. The preferred embodiment of figure 2 corresponds to that of figure 1, expect that the biofilter (2) is advantageously of a different size than the composter unit (3) . In this case the mixer blades (5a, 5b) are also of different sizes.

Claims: PATENT CLAIMS 1. An apparatus for composting organic waste, comprising a biofilter unit (2) and a composter unit (3) , and a combined • common feed point (1) and a common intermediate bottom (16), c h a r a c t e r i z e d in that the mixing of the biofil¬ ter unit (2) and the composter unit (3) is carried out by means of a common mixer equipment (4a, 4b) , and that the intermediate bottom (16) is, below the feed point (1) , pro¬ vided with a drop hatch (8) , whereby the waste can be directed to both units. 2. The apparatus of claim 1, c h a r a c t e r i z e d in that the intermediate bottom is advantageously provided with another drop hatch (9) . 3. The apparatus of claim 1 or 2, c h a r a c t e r i z e d in that the intermediate bottom (16) between the biofilter unit (2) and the composter unit (3) is perforated, in which case the air-blower (14) can advantageously be either elim¬ inated or reduced in size. 4. The apparatus of any of the preceding claims, c h a r ¬ a c t e r i z e d in that the volumes of the biofilter unit (2) and the composter unit (3) are advantageously different from each other. 5. The apparatus of any of the preceding claims, c h a r -. a c t e r i z e d in that in comparison with the composter unit (3), the biofilter unit (2) is advantageously operated with a longer delay time, and that from the biofilter (2) the mass is dropped, through the drop hatches (8, 9) to the composter unit (3) . 6. The apparatus of any of the preceding claims, c h a r ¬ a c t e r i z e d in that in the biofilter unit (2) there is advantageously used a particularly loose mass, in which case the procession of air through the perforation in the intermediate bottom (16) is intensified. 7. The apparatus of any of the preceding claims, c h a r ¬ a c t e r i z e d in that the mass used in the biofilter unit (2) is advantageously the waste treated in the compost¬ er unit (3) .

Inventors: PIPPING ISABEL ALINE, STENROOS ARTO ILMARI, PIPPING, ISABEL, ALINE, STENROOS, ARTO, ILMARI
Applicants: OUTOKUMPU OY
Application year: 1989
Main classification: C05F9
IPC codes: C05F7, C05F9, C05F17