JPS6352000B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for composting livestock manure.

Wet livestock dung mixed with urine and washing water has a moisture content of approximately 85%, making it difficult to compost as it is. composting was carried out after lowering the moisture content to 66-67%. However, the fertilizer effect of the produced compost is low, and recently it has become difficult to obtain sawdust, rice husks, etc., so before composting, wet livestock manure is dehydrated and adjusted to a state where it is easy to ferment using a dehydrator. However, a new problem has arisen: how to detoxify the waste water from the squeeze water separated during dehydration and humidity control.

The object of the present invention is to provide a method and apparatus for composting wet livestock manure without discharging sewage, sludge, etc. that cause secondary pollution to the outside of the system. Approximately half of the wet livestock manure to be treated is dehydrated and moistened to a state that is easy to ferment, separated into squeezed wastewater and moistened livestock manure, and the squeezed wastewater is introduced into an anaerobic digestion tank for digestion treatment. Methane gas is generated and digested sludge is generated in the same tank, and primary fermentation is carried out while blowing hot air obtained by using the generated methane gas as fuel into the humidity-conditioned livestock manure, and the product obtained in the primary fermentation is The remaining half of the wet livestock manure to be treated as described above is mixed with the dried compost, and the moisture is adjusted to a state that facilitates fermentation. The purpose is to mix and absorb the digested sludge produced in the anaerobic digestion tank into the dry compost obtained by the next fermentation without discharging it outside the system, thereby producing compost with adjusted moisture content. The devices used to achieve this method include a screw press that dehydrates and moistens almost half of the wet livestock manure to be treated, and an anaerobic digestion system that introduces and digests the squeezing water sewage separated by the screw press. A tank, a hot air generator that generates hot air using the methane gas generated in the anaerobic digestion tank as fuel, and dehydration and humidity control using the screw press while blowing in the warm air generated by the hot air generator. A primary fermentation tank into which the humidified livestock manure is transported and agitated for primary fermentation, and a state in which approximately half of the remaining wet livestock manure to be treated is mixed with the dry compost obtained in the primary fermentation to facilitate fermentation. and a secondary fermentation tank into which the humidity-adjusted mixture obtained by the mixing means is brought in and subjected to secondary fermentation by stirring and aeration, A pump and a drawing pipe are provided for introducing the digested sludge into the secondary fermentation tank, and an embodiment shown in the drawings will be described.

Approximately half of the wet livestock manure A to be processed is put into the hopper 11 of the screw press 1 by the conveyor 71, and dehydrated and humidified by the screw press 1 to make it easy to ferment. It is dehydrated and separated into squeezed wastewater and humidified livestock manure _A1 . The squeeze water wastewater separated from the porous wall 12 passes through the saucer 14 and the drain pipe 15 and accumulates in the storage tank 16.
Next, it is sent into the anaerobic digestion tank 2 via the water pipe 18 by a pump 17 with an electric motor. On the other hand, the humidity-controlled livestock manure A ₁ discharged from the discharge port 13 of the screw press 1 is conveyed to the primary fermentation tank 4 by a conveyor 72 .

The anaerobic digestion tank 2 is equipped with a heat insulating cover 21 and a floating cover 22, and the anaerobic digestion tank 2 is equipped with a heat insulating cover 21 and a floating cover 22.
The methane gas generated inside is stored in the floating cover 22, and the floating cover 22
is supplied to the gas burner 31 of the hot air generator 3 through the gas extraction pipe 23 under pressure due to its own weight, and
The digested sludge generated in the digestion tank 2 is transferred to the sludge extraction pipe 24.
The sludge is introduced into the secondary fermentation tank 6 through the sludge inlet 66 of the secondary fermentation tank 6 by the pump 25 and the sludge inlet 66 of the secondary fermentation tank 6. A desulfurizer may be inserted into the gas extraction pipe 23 if necessary.

The hot air generator 3 includes a gas burner 31, a combustion chamber 32, an air intake pipe 33, and a blower 34, and the generated hot air is passed through the blower 34 to the blower pipe 35 and the hot air introduction pipe 49 of the primary fermentation tank 4. It is designed to be blown into the primary fermentation tank 4 through.

As shown in FIG. 2, the primary fermentation tank 4 includes an agitator 4 attached to a vertical shaft 44 that is rotated at a reduced speed by a motor a, a worm b, and a worm wheel c.
1, an unloader 42, and a nozzle 43 arranged at the bottom of the tank. The transport device, for example the rake 42, is equipped with a large number of transport plates, and is used to collect dry compost A ₂ that has undergone primary fermentation.
is discharged from the discharge port 45 (see Fig. 2). The nozzle 43, as shown in FIG.
It is attached to an annular header 46 arranged double-layered inside and outside, and a nozzle hole 4 is formed horizontally on the side surface of its upper end.
7 (see Figure 5). Annular header 46
is connected to a hot air introduction pipe 49 through a branch pipe 48, and the hot air introduction pipe 49 is connected to the blast pipe 35 of the hot air generator 3.

The mixing means 5 includes an outlet 45 of the primary fermentation tank 4.
The dry compost A ₂ that has undergone primary fermentation and is discharged from the hopper is mixed with the remaining half of the wet livestock manure A to be treated that is carried in by the conveyor 73 to adjust the humidity. The mixed humidity control mixture _A3 is fed into a hopper 65 of the secondary fermentation tank 6 via a conveyor 74.

The secondary fermentation tank 6, as shown in FIG. It is attached to an air supply pipe 64 placed at the bottom, and, like the nozzle 43 placed at the bottom of the first fermentation tank 4, a nozzle hole is provided on the side surface of the upper end. 65 is the humidity control mixture A ₃ as described above.
66 is a sludge inlet port through which the digested sludge generated in the anaerobic digestion tank 4 is sent through the pump 25 and the sludge extraction pipe 24;
Reference numeral 67 is a compost discharge port for discharging usable compost by mixing and absorbing the digested sludge into the dry compost obtained by secondary fermentation to obtain the desired moisture-adjusted compost. Moisture-adjusted compost
A ₄ is conveyed out of the apparatus by a conveyor 75.

Anaerobic digestion tank 2 and primary fermentation tank 4 in the present invention
It is preferable that the respective capacities of the secondary fermenter 6 and the secondary fermenter 6 are as follows. That is, anaerobic digestion tank 2
The capacity of the primary fermentation tank 4 is large enough to store approximately 20 days' worth of squeeze water wastewater that is sent in each day, and the capacity of the primary fermentation tank 4 can store approximately 15 days' worth of humidity-controlled livestock manure _A1 that is inputted each day. In terms of size, if the capacity of the secondary fermentation tank 6 is designed to be large enough to store about 15 days' worth of humidity control mixture _A3 input in one day, it will become a suitable livestock manure composting device.

To explain the operation of the livestock manure composting method and apparatus of the present invention constructed as described above, for example, urine and washing water from the livestock house are mixed in and the moisture content is reduced.
Approximately 85% of the wet livestock manure is carried out using a cat cart, etc., and the wet livestock manure A, which is half of the amount generated in a day, is transferred to conveyor 7.
1, put it into the hopper 11 of the screw press 1, operate the screw press 1, and compress and dehydrate the livestock manure A so that it can be easily fermented, for example, to have a moisture content of about 58-60%. At that time, it is separated into squeezing water wastewater coming out of the porous wall 12 and humidity-controlled livestock manure _A1 coming out of the discharge port 13. The waste water from one of the squeezed water passes through the saucer 14 and the drain pipe 15, accumulates in the storage tank 16, and is then sent into the anaerobic digestion tank 2 via the water supply pipe 18 by the motorized pump 17, and is sent to the other humidity-controlled livestock tank. Feces A ₁ is on conveyor 72
It is carried into the primary fermentation tank 4.

The squeezed water wastewater sent to the anaerobic digestion tank 2 is
It contains a BOD of 15,000 to 20,000 PPM and a solids concentration of 6 to 8%. In the anaerobic digestion tank 2, the squeezed water wastewater is digested to generate methane gas and digested sludge with a BOD of about 3,000 to 4,000 PPM. The generated methane gas is stored in the floating cover 22, and the gas extraction pipe 2 is pumped under pressure due to the weight of the floating cover 22.
3 to the gas burner 31 of the hot air generator 3, and the digested sludge is pumped in an amount equivalent to the amount of squeezed water sewage sent to the anaerobic digestion tank 2 every month using the motorized pump 17. At 25, the sludge is drawn out through the sludge drawing pipe 24, and sent into the secondary fermentation tank 6 through the sludge inlet 66 of the secondary fermentation tank 6.

In the hot air generator 3, methane gas supplied by the gas burner 31 burns in the combustion chamber 32 to become high-temperature gas, which is then passed through the air intake pipe 33.
The air taken in from the air is mixed to produce warm air at approximately 60°C, and the hot air is pressurized by the blower 34 and sent to the air pipe 3.
5 and is introduced into the primary fermentation tank 4 from the hot air introduction pipe 49 of the primary fermentation tank 4.

In the primary fermentation tank 4, the humidity-controlled livestock manure _A1 carried in by the conveyor 72 is stirred by an agitator 41 that is slowly rotated by a motor a, a worm b, a worm wheel c, and a vertical shaft 44. , gradually settles and accumulates toward the bottom of the tank. As described above, the hot air introduced from the hot air generator 3 into the hot air introduction pipe 49 passes through the branch pipe 48 and the annular header 46 to the primary fermentation tank 4.
It is blown into the accumulated livestock manure from a nozzle 43 arranged at the bottom of the tank. The humidified livestock manure _A1 is aerobically maintained and fermented by stirring by the stirrer 41, and the fermentation is further promoted by the warm air blown in the above-mentioned state, and as the fermentation progresses. The temperature inside the tank reaches approximately 70 degrees Celsius due to fermentation heat, and composting takes place while the water in the livestock dung evaporates. Fermentation is completed and tank 4
The dry compost A ₂ that has settled and accumulated at the bottom has a moisture content of approximately
15%, which is discharged from a discharge port 45 to a mixing means, for example, a hopper 5, by a discharge device 42 attached to the lower end of the vertical shaft 44.

In the hopper 5, the dry compost A2 discharged from the primary fermentation tank ₄ is mixed with wet livestock manure A, which is half the amount generated in a day and carried in by the conveyor 73, to adjust the moisture content to about 65%. moistened humidity control mixture
_A3 , and the humidity-adjusted mixture _A3 is fed into the hopper 65 of the secondary fermentation tank 6 via the conveyor 74.

In the secondary fermentation tank 6, the humidity-controlled mixture _A3 fed from the hopper 65 is mixed in the dry compost by the agitator 61 which rotates slowly by the deceleration motor d and the horizontal shaft 63. A large amount of fermenting bacteria are inoculated into the wet livestock manure, and fermentation is promoted by air introduced from the nozzle 62 of the blower pipe 64 to perform composting. After the composting is completed, A pump 25 pumps the digested sludge generated in the anaerobic digestion tank 2 into the generated dry compost.
The sludge is drawn out through the sludge drawing pipe 24 and transferred to the secondary fermentation tank 6.
The sludge is fed into the secondary fermentation tank 6 from the sludge inlet 66,
It is mixed with the dry compost mentioned above, absorbed into the dry compost to become moisture-adjusted compost _A4 , and discharged from the discharge port 67.
It is carried out of the apparatus by a conveyor 75.

The method and apparatus for composting livestock manure according to the present invention dehydrates and moisturizes approximately half of the wet livestock manure to be treated, so it is difficult to dehydrate and moisturize the entire amount of livestock manure at once. Comparatively, the amount of wastewater from the squeeze water is about half, and the solids contained in the wastewater are also small, so the digestion process is carried out quickly, and the amount of digested sludge produced by the digestion process is also reduced. , this generated digested sludge can be mixed and absorbed into the dry compost after secondary fermentation for composting treatment, and the remaining half of the amount to be treated can be added to the dry compost obtained from the primary fermentation. It is mixed with compost to adjust the moisture content and perform secondary fermentation to make it easier to ferment.
There is no need to mix sawdust, rice husks, etc., which are difficult to obtain, in order to adjust the humidity of wet livestock manure, and there is no fear that the mixture of sawdust, rice husk, etc. will reduce the fertilizing efficiency of the compost. As mentioned above, the sludge generated through the digestion treatment of squeeze water sewage is composted by being sent to a secondary fermentation tank using a pump and sludge extraction pipe without discharging it outside the system. This eliminates the need for biological treatment equipment for sewage and sludge drying equipment, which were required in the past to further detoxify the sewage and sludge discharged through digestion in a digestion tank. It is effective.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the process diagram of the present invention, and FIG.
The figure is a vertical cross-sectional elevation view of the primary fermentation tank, Figure 3 is a cross-sectional plan view taken along the - line in Figure 2, Figure 4 is a partially cutaway side view of the secondary fermentation tank, and Figure 5 is an enlarged view of the nozzle. FIG. 1: Dehydrator, 2: Anaerobic digestion tank, 3: Hot air generator, 4: Primary fermentation tank, 5: Mixing means, 6: Secondary fermentation tank, A: Moist livestock manure, A ₁ : Humidified livestock manure ,
A ₂ : Dry compost, A ₃ : Moisture-adjusted mixture, A ₄ : Moisture-adjusted compost.

Claims (1)

[Scope of Claims] 1 Approximately half of the wet livestock manure to be treated is dehydrated and moistened to a state where it can be easily fermented, separated into squeezed wastewater and moistened livestock manure, and the squeezed wastewater is passed through an anaerobic digestion tank. At the same time, digested sludge is generated in the same tank, and primary fermentation is carried out while blowing the warm air obtained using the generated methane gas as fuel into the humidified livestock manure. Then, the remaining half of the wet livestock manure to be treated is mixed with the dry compost obtained in the first fermentation to adjust the moisture content to a state that facilitates fermentation, and the mixture is heated while aerating. By carrying out a second fermentation and mixing and absorbing the digested sludge produced in the anaerobic digestion tank into the dry compost obtained by the second fermentation without discharging it outside the system, it is possible to create moisture-adjusted compost. A method for composting livestock manure, characterized by: 2. A screw press that dehydrates and moistens approximately half of the wet livestock manure to be treated, an anaerobic digestion tank that introduces and digests squeezed water sewage separated by the screw press, and the anaerobic digestion tank. A hot air generator that generates warm air using the methane gas generated by the hot air generator as fuel, and the humidified livestock manure that has been dehydrated and humidified using the screw press while blowing in the warm air generated by the hot air generator and is agitated. a primary fermentation tank for carrying out primary fermentation, and a mixing means for mixing approximately half of the remaining wet livestock manure to be treated with the dry compost obtained in the primary fermentation tank to adjust the humidity to a state that facilitates fermentation. , a secondary fermentation tank is provided in which the humidity-controlled mixture obtained by the mixing means is carried in and subjected to secondary fermentation by stirring and aeration, and the digested sludge produced in the anaerobic digestion tank is fermented in the secondary fermentation tank. A composting device for livestock manure, characterized in that it is equipped with a pump and a pull-out pipe for introduction into a fermentation tank.