RU2264368C2 - Method for preparing of compost - Google Patents

Abstract

FIELD: agriculture, in particular, processing of organic wastes.

SUBSTANCE: method involves providing dosed feeding of manure or dung and moisture-absorbing material into mixer; moving mixture into fermenter and performing aerobic composting. Manure or dung is fed into mixer zone where moisture-absorbing material is fed through screw-type conveyor having length of at least 8 m, and later through brush-type drum having circumferential velocity of 4-7 m/s. Method further involves discharging mixture from mixer outlet end by means of screw-type conveyor having length of at least 8 m through brush-type drum having circumferential velocity of 4-7 m/s.

EFFECT: improved quality of ready product, increased maximal moisture content of manure or dung which may be exposed to processing, and increased efficiency.

3 dwg, 3 ex

Description

The invention relates to agriculture and can be used in the processing of organic waste, in particular manure and litter.

A known method of preparing compost, in which the processed manure or litter and other organic waste is stacked in layers with moisture-absorbing carbon-containing materials (peat, sawdust, etc.), mixed and composted (Organic fertilizers, Handbook. M.: Agropromizdat, 1988, p. 150-152). The specified method is characterized by high losses of nutrients due to the active occurrence of anaerobic processes due to weak contact of the composted material with atmospheric oxygen.

A known method of preparing multi-purpose compost, including layering manure and moisture-absorbing material of organic origin, adding finished compost in a ratio of 9: 1, mixing while moving the mixture to the fermenter and subsequent aerobic composting with periodic ventilation for 3-4 days (RF Patent No. 2112764, MKI C. C 05 F 3/00, 1998). The disadvantage of this method is the inhibition of aerobic processes due to insufficient porosity of the composted mixture and, as a consequence, the low productivity of the composting process due to the inability to load the fermenter to the optimum height.

The closest technological solution, selected as a prototype, is a method of composting, which includes dosed feeding of manure or litter with a loader into a mixer, where moisture-absorbing material of organic origin (peat, straw, etc.) is also fed, and then the mixture is transferred to a fermenter composting (V.P. Lysenko. Processing of poultry waste, Sergiev-Posad, 1998, p. 76-77). However, in this method, the homogeneity and porosity of the composted mixture is not provided, which are necessary to ensure sufficient contact with atmospheric oxygen, especially in the initial stage of fermentation, as a result of which anaerobic processes are violently occurring, which leads to the suppression of aerobic processes, i.e. losses of nutrients.

The result of the invention is improving the quality of the finished product, plant productivity and the upper limit of humidity of the processed manure or litter.

The problem is achieved in that in the known method of preparing compost, comprising a dosed feed of manure or litter and moisture-absorbing organic material into the mixer, moving the resulting mixture to the fermenter and subsequent aerobic composting, manure or litter is fed to the mixer through a screw conveyor with a length of at least 8 m and then a brush drum with a peripheral speed of 4-7 m / s, feeding into the mixer is carried out in the zone of downward flows formed in the mixer, which receives a moisture-absorbing organic material al. The working bodies of the mixer are parallel screws with spirals of the right and left coils, set in such a way that in the bottom part the mass moves from the center to the end walls, and in the upper part from the walls to the center, creating a downward flow of the mixture into the center, into which the crushed with a brush drum (one or two) manure (litter). Wet particles of manure (litter), meeting in the mixer with particles of moisture-absorbing organic material, instantly adhere to it, forming granules resistant to sticking, which are carried away in a downward flow to the bottom, creating a loose aerated structure of the mixture. At the outlet of the mixer, the mixture passes through a screw conveyor with a length of at least 8 m and a brush drum with a peripheral speed of 4-7 m / s and enters the fermenter.

The indicated set of features makes it possible to ensure the suppression of anaerobic processes throughout the technological chain due to loosening of manure or litter and grinding of particles to 2-4 mm with simultaneous saturation of oxygen with air up to 12-15%, which leads to an improvement in the quality of the compost obtained, an increase in plant productivity by 10- 20% (due to the possibility of loading the fermenter to the optimum height) and increasing the upper limit of humidity of the processed manure or litter.

In FIG. 1 shows the dependence of the fermentation temperature on the preliminary saturation of the composted mixture with oxygen under the conditions of the proposed method and prototype. The time to reach the maximum temperature in the proposed method (t ₁ ) is reduced by about 5 hours compared to the prototype (t ₂ ) when composting manure with peat and by 18 hours when composting cattle manure (cattle) with peat, i.e. pre-saturation with oxygen at the stage of preparation of the mixture on the screw conveyor and brush drum can reduce the duration of the composting process compared to the prototype by 20-25%. The maximum temperature in the mixture of litter with peat reaches 82.2 ° С, in the mixture of cattle manure with peat - 68.8 ° С. T _about - ambient temperature.

Figure 2 shows the dependence of the height of the bulk layer in the fermenter on the moisture content of the composted mixture in the proposed method and prototype. The data show that the proposal allows to increase the achieved height of the bulk layer of the mixture in the fermenter by 10-20% compared with the prototype.

It has been found that with a screw conveyor length of less than 8 m, the pasty component is saturated with oxygen below 12%.

When the peripheral speed of the brush drum is less than 4 m / s, a decrease in the particle size of the manure or litter to 2-4 mm is not achieved, and an increase in the peripheral speed of over 6 m / s is not economically feasible.

The greatest efficiency is achieved when mixed materials are fed into the downstream zone formed in the mixer. In this case, the particles of moisture-absorbing organic material firmly envelop the particles of manure or litter, while achieving high homogeneity of the mixture, which is loosened and crushed at the outlet of the mixer by passing through a screw conveyor at least 8 m long and a brush drum with a speed of 4-6 m / s for obtaining high porosity of the material, which provides the optimal filling height of the fermenter.

Thus, the results of the studies indicate the achievement of the specified technical result and the right choice of optimal technological parameters.

Implementation of the proposed method is as follows (figure 3).

Manure (litter) from the hopper 1 through two blade augers 2 enters the auger conveyor 3, where it is loosened, mixed and fed through the brush drum 4 into the downward flow zone of the mixer 5. Moisture-absorbing organic material (peat 6) is also fed there by a loader 6 , straw, etc.) from the collar 10. The number of incoming components is recorded by a weighing device 7. A homogeneous mixture is fed through a conveyor 8 to a brush drum 9 and delivered by a loader 6 to a fermenter 11 equipped with a fan 12, on compost ry with obtaining the finished product.

Example 1

The method described above was used to compost cattle manure (cattle) with a moisture content of 60% and peat. Manure was fed into the mixer under the following conditions: screw conveyor length 3-6 m, brush drum peripheral speed 4-3 m / s; and unloading from the mixer - when the length of the screw conveyor is 8-7 m, the peripheral speed of the brush drum is 9-3 m / s. The low porosity of the composted mixture, a decrease in the loading height and fermenter productivity compared with the achieved technical result by 30% are noted. Received compost of poor quality.

Example 2

Everything, as in example 1, but other conditions at the inlet and outlet of the mixer 5. At the entrance: the length of the screw conveyor is 3-8 m, the rotation speed of the brush drum is 4-5 m / s. At the exit: the length of the screw conveyor is 8-8 m, the rotation speed of the brush drum is 9-5 m / s. The desired performance of the installation is achieved and the high quality of the biocompost is ensured.

Example 3

Everything, as in example 1, but the loading conditions in the mixer 5: the length of the screw conveyor 3-10 m, the rotation speed of the brush drum 4-7 m / s; and at the outlet of the mixer 5: the length of the screw conveyor is 8-10 m, the rotation speed of the brush drum is 9-7 m / s. The specified technical result is achieved.

Our studies showed the possibility of a successful process at a maximum humidity of 76.9% for a compostable mixture based on cattle manure and 83.0% based on bird droppings. In the practice of aerobic processing, this allows one to significantly save expensive moisture-absorbing organic material (up to 30-40% wt. Peat or straw) and focus on mixing only the optimal ratio of carbon to nitrogen in the final product (25-30: 1).

Claims (1)

A method of preparing compost, including a dosed feed of manure or litter and moisture-absorbing organic material into the mixer, transferring the mixture to the fermenter and subsequent aerobic composting, characterized in that the manure or litter is fed into the mixer into the feed zone of the moisture-absorbing material through the screw conveyor with a length of at least 8 m, and then a brush drum with a peripheral speed of 4-7 m / s, and at the outlet of the mixer, the mixture is unloaded with a screw conveyor at least 8 m long through a brush drum with a peripheral speed 4-7 m / s.

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