FI98300C - composter - Google Patents

Description

98300

COMPOSTER

The present invention relates to a composter comprising a mixing tank, two or more reaction tanks for actual composting located inside the mixing tank and a cola conveyor moving around the reaction tanks for transferring the premixed mass from the mixing tank to the reaction tank. the reaction container. The composter is used to compost 10 biomasses by the aerobic method. Such biomasses include livestock manure, peat, straw, grass, wood chips, tree leaves, garden waste, municipal waste.

The composter is most typically used to treat sewage sludge, fur-15 animal waste, livestock manure, and household and garden waste. In this treatment, the biomass is decomposed so that the nutrients it contains remain in a form suitable for plant use. The pulp decomposed in this way is called compost and is used in gardens.

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Composting of biomass requires suitable conditions for composting. The moisture content of the mixture must be suitable, the moisture content must not exceed approx. 70%, ie the dry matter content must be at least approx. 30%. The optimum moisture depends on the composition of the mixture. The carbon / nitrogen mixture ratio must be appropriate and the mixture must be airy to obtain a sufficient amount of oxygen for the decomposition activity of the micro-biomass required for composting to take place. Composting and composers have been explained, for example, in the book: Water and Others-30 Environmental Board's handout series No. 2, Composting of sewage sludge from the forest industry, Jouko Halminen, Helsinki 1986. Composters have been presented e.g. in Patent Publication Nos. 29585, 75335, 77641 and 77836. SE Publication No. 307961 discloses a composter according to the preamble.

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The composting process is characterized by a necessary rise in temperature. As the temperature develops, the following stages can be distinguished: the heating stage, the heating stage and the cooling stage (post-ripening stage). Known composers and composting methods have the disadvantage of controlling the entire composting process from mixing to finished, decomposed compost. Composting is disturbed or does not occur at all if too much or too dry mass enters the composter. In the composter itself, mixing is usually difficult to perform. For example, patent 77641 discloses a solution for ensuring mixing when fed to a composter. The aim of the composting process is generally to be carried out in the same state as a continuous process, so that the heating step and the thermal step and the partial cooling step take place in the same state or the cooling step takes place in a different state. jälkikyp-sytyskasassa. In this case, there is a risk that composting will not take place completely in the whole pulp.

A further disadvantage of known composters when composting sludges is that a very large amount of admixtures must be used in order to achieve the sufficient dry matter content required for composting. For example, the typical dry matter content of livestock manure and sewage sludge is only approx.

20 10% and even lower for many industrial sludges. Composting of such sludges requires admixtures, e.g. peat, in an amount of about 3-4 times the amount of sludge measured by volume. Therefore, the size of the composter must be large so that the desired amount of sludge can be processed by composting. The alloying agents also pay and the handling costs increase as the amount of pulp to be treated increases.

The object of the present invention is to provide a novel composter in which the above disadvantages are avoided. The characteristic features of the invention are set out in the appended claims. Here, a cola conveyor means any corresponding conveyor using an endless rotation.

The invention will now be illustrated by reference to the accompanying drawings, which show some embodiments of the invention.

Figure 1 shows the composter seen from the side.

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Figure 2 shows a cross-section of the composter of Figure 1 looking in the direction of arrow AA.

Figure 3 shows a cross-section of a composter equipped with an electrolysis apparatus according to the present invention. 5 Figure 4 shows a detail of the bottom structure of the composter of Figure 3.

When composting the pulp as it is without filtration, the procedure is as follows, with reference to Figures 1 and 10. 2. The composter shown in the figures is built on a trailer 4 comprising a frame, a gear and a drawbar. The main parts of the composter are a mixing tank 1, reaction tanks 2, here 2, tanks a and b and a cola conveyor 5. Around the mixing tank 1 there is a thermal insulator 20, which is preferably formed in a known manner from polyurethane.

The mixing tank comprises a filling hatch 11 and an outlet hatch 12. The top-covered reaction tanks 2 comprise a filling hatch 10 and an outlet screw conveyor 6.

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The compostable masses are fed to the mixing tank 1. If compostable sludge (e.g. livestock sludge or sewage sludge) is composted, it is pumped into the mixing tank 1 via a sludge pumping connection 9 in a predetermined amount by a known technique. After pumping the sludge, the desired amount of dry matter (e.g. peat) is fed with the hatches 11 open. The amounts of the ingredients can be determined in advance to achieve a suitable mixing ratio or the mixture can be examined after mixing and, if necessary, a drier or wetter mass is added to achieve the correct mixing ratio.

When feeding dry matter, a cola conveyor 5 can be started, which also acts as a mixer here. The flighted conveyor 5 in Figure 1 to rotate in a clockwise direction of arrow 35 to form a closed ring around the two one inside the mixing tank and reaction vessels. The cola conveyor 5 transfers the fed dry matter from the reaction tanks 2 and 3 when the filling tanks 10 of the reaction tanks are closed. The dry matter falls out of the top of the reaction tanks as it enters the mixing tank by moving the cola conveyors 5. As it travels, the cola conveyor 5 pushes the mass towards the bottom, whereby the masses on the surface and on the bottom mix with each other. At the bottom, the cola conveyor moves the mass forward and part of the mass erupts 5 from the cola conveyor, mixing with the rest of the mass. When the filling hatches 10 of the reaction tanks and the discharge opening 12 of the mixing tank 1 are closed, the cola converter 5 mixes the masses efficiently with each other. The cola conveyor 5 also efficiently mixes the air into the pulp. The cola conveyor is allowed to run until complete mixing has taken place. The conveyor can also be used during composting as needed to mix and aerate the pulp. Once the different pulps have been fed and mixed in the correct proportions in the mixing tank, composting begins. The mass begins to heat up, i.e. the warming phase 15 begins. When the pulp has warmed up, it is transferred from the mixing tank 1 to the reaction tanks 2 and 3. The pulp is transferred by opening the filling tank 10 to which the pulp is to be transferred and the reaction container.

In reaction tanks 2 and 3, the thermal step of composting takes place. The air required for the composting process of the pulp enters the pulp through aeration pipes 8 blown by aeration fans 7 or 25 without the use of blowers as a free air flow.

In the reaction tanks 2 and 3, the heat generated in the composting process is due through the walls to the mixing tank 1 and this heat raises the temperature of the pulp in the mixing tank, speeds up the composting process and allows the process to start even in winter conditions. If the reaction tanks 2 and 3 are empty and no heat is then generated in them, warm air can be blown into the reaction tanks 2 and 3 through the aeration pipes 8, whereby heat is conducted through the walls to the mixing tank 1. 35

When the heat step is over in the pulp in the reaction tank, the pulp begins to cool. The cooling step can be allowed to take place in reaction tanks 2 and 3 or the pulp can be allowed to cool outside the composter 5 98300 in the post-ripening heap after the reaction tanks have been emptied. The reaction tanks 2 and 3 are emptied by starting the discharge conveyor 6, which transfers the pulp from the reaction tanks to the sides of the composter.

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There can be any number of reaction tanks required and different reaction tanks can be used in composting, e.g. so that different reaction tanks have different or different composting stages.

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The automation and control logic required by the composter are placed in the control center 13.

The rear wall of the mixing tank is arranged obliquely and said unloading hatch 12 is formed at its upper end 15. The cola conveyor 5 is suspended around the required number of folding wheels, one or more of which are traction. The rising part of the cola conveyor is covered with a cover plate 21 up to the first reaction tank, whereby the cola conveyor carries even the wet mass with it.

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If it is desired to filter the sludge to be composted, the procedure is as follows, Figures 1, 3 and 4. Here, a variant of the composter is used, which includes an electrolysis apparatus 14 known per se for electrochemical treatment of the incoming sludge and a filter base peat layer and forms a water collection space on the actual bottom 22, from which the leaking water can drain through the channels 24 into the reject water pipes 17, Fig. 4.

With the dry matter filling hatches 11 open, the desired amount of filtration material 16 is fed to the mixing tank 1. By means of the cola conveyor 5, the filtering material 16 is applied to the bottom of the mixing tank 1 into an even layer, the preferred thickness of which when using the filtering material is peat is about 30 cm. 35 Peat is an inexpensive filtration material due to both its filtration properties and compostability.

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After the filtration material 16 has been applied to the bottom of the mixing tank, the slurry 15 is fed through the slurry pumping connection 9 to the electrochemical apparatus 14 and further to the mixing tank 1 in the desired amount. By treating the slurry 15 with electrochemical equipment 14 known per se, it is made to filter faster and better than without electrochemical treatment. Experiments have shown that without such treatment, livestock manure cannot be filtered with a peat filter because the manure clogs the filter. Once the desired amount of slurry 16 has been fed, it is allowed to filter 10. The solids and nutrients in the slurry 15 seep into the filtration material 16 and most of the liquid seeps through the filtration material into reject water 18 into the above-mentioned reject water pipes and only a small part of the liquid binds to the filtration material. The slurry 15 is always fed further as the infiltration 15 progresses as described above so that the slurry is always on top of the filter material. How often the sludge is added depends on both the sludge and the filtration material.

The reject water 18 seeping through the filter material 16 flows into the reject water pipes 17, and further out along the equipment. When filtering the sludge 15, the reject water pipes 17 are kept constantly open.

When the filtration capacity of the filtration material 16 is exhausted, i.e. the slurry 15 25 no longer seeps but remains on top of the filtration material, the filtration material 16 and the solids, nutrients, etc. of the slurry 15 leached into it can be further processed e.g. by composting. In this case, proceed as follows. Additional peat is fed to the mixing tank 1 with the dry matter filling hatches 11 open. The feed dry matter is mixed with the compostable filter material 16 and the components of the slurry 15 leached therein by means of a cola conveyor 5. The conveyor is rotated with all the doors closed until the mass to be mixed is homogeneous. If necessary, dry matter can be added to the mixing tank 1 so that the moisture of the mixed mass is made suitable for composting. When the pulp is suitable for composting, it can, depending on the situation, be composted with this composter at the initial stage in the mixing tank 1 and transferred to it.

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7 98300 to reaction vessel 2 or 3 following the procedure described previously. The pulp can also be composted e.g. Once the mixing tank 1 has been emptied of the mixture, the filtration can be continued as described above.

By filtering the sludge before composting, the advantage is obtained that the solids, nutrients, etc. in the sludge, due to which the sludge is actually treated by composting, can be separated from the liquid. Since the slurry typically contains only about 10% solids and the rest dry matter, the mass to be composted after filtration is only about 10-20% compared to composting the slurry with e.g. peat as such. The liquid that seeps through the filter 15 is called the reject water 18 is further treated on a case-by-case basis according to purity requirements.

One of the tested electrolysis plants was designed for a sludge volume of 1.5 m3 / h. In this case, electro-20s with a size of 0.1 to 0.2 m2, a voltage of 15 to 40 V and an electric current of 15 to 40 A are used.

The composter can be automated using a well-known technique so that most functions such as mixing, aeration and mass transfers take place automatically.

The composter can also be built to be fixed in place instead of the one shown here. In the version shown here, the composter can be easily moved from one place to another and can also be used for transferring and spreading the pulp 30.

The invention is not limited to the embodiments shown in the description and the drawings, but the invention can be modified in many ways within the scope of the appended claims.

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Claims (11)

Composting plant, comprising a mixing container (1), two or more reactor containers (2, 3) for the actual composting, located within the mixing container 25 (1) and a scrap conveyor (5) moving around the reactor containers (2). 3) for moving the premixed mass from the mixing vessel (1) to the reactor vessel (2, 3), which conveyor is adapted to mix the masses to be composted and dropping the mixed mass into respective reactor vessel (2, 3). characterized in that the composting plant comprises an electrolysis plant (14) known per se for electrochemical treatment of the input sludge prior to its introduction into the mixing container (1) and on the bottom of the mixing container (1) a peat filter (16) is adapted through forming water discharge channels to the bottom (17) and arranging space for the peat layer beneath the reactor vessels (2, 3), plenty of water from the sludge before composting. 10 98300 Composting plant according to claim 1, characterized in that the water outlet channels comprise a continuous water collection space formed by the perforated intermediate bottom (23) and the tubes (17) fixed to the lower bottom (22) which are connected to channels for water collection space. meth. Composting plant according to Claim 1 or 2, characterized in that each reactor container (2, 3) is a closed vessel, the upper part of which includes an openable lid, which is arranged in line with the conveyor (5). Composting plant according to any of claims 1 to 3, characterized in that each reactor container (2, 3) is provided with a transverse screw conveyor (6) seen from the conveyor (5) which removes the finished mass to the side of the composting plant. . Composting plant according to any one of claims 1-4, characterized in that each reactor container (2, 3) is provided with aeration pipes for introducing air into the mass to be composted. Composting plant according to any of claims 1-5, characterized in that the mixing container (1) comprises a leaking sloping edge (19) along which the conveyor (5) is adapted to run and wherein there is provided an openable door (12) for removing the pulp from the mixing vessel (1). 30 Composting plant according to any of claims 1-6, characterized in that the mixing vessel (1) is formed by a longitudinal vessel in the direction of the conveyor (5), each reactor container (2, 3) extending over the entire width of the mixing vessel 35 (1). and that the outer surfaces of the mixing container (1) are thermally insulated. li 11 98300 Composting plant according to any of claims 1-7, characterized in that the rising part of the scrap conveyor (5) is covered with a cover plate (21) up to the reactor container. 5 Composting plant according to any of claims 1-8, characterized in that the composting plant has been built on a trailer.