JP2007284332A - Method and apparatus for producing compost raw material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means for producing a compost raw material, composting the raw material in a short term and capable of adjusting its pH at a low cost. <P>SOLUTION: The apparatus is one provided with means for throwing the contents in an aeration tank 1 and in a sludge storage tank 4 into a mixing tank 5, a cutter-fitted submerged filth pump 22 provided in the lower part of a storage tank 21, and a submerged filth pump 28 provided in the lower part of a mixing tank 27, and agitators 23, 29, and 34 provided in the storage tank 21, the mixing tank 27, and a coagulation tank 33 respectively, wherein a connection is made between the discharge port of the cutter-fitted submerged filth pump 22 and the upper part of the mixing tank 27, a connection is made between the discharge port of the submerged filth pump 28 and the upper part of the coagulation tank 33, connections are made between the discharge port of a blower 39 of an additive tank 38 and the upper part of the mixing tank 27 and between the discharge port of a chemical injection pump 37 and the upper part of the coagulation tank 33, and connections are made between the inlet of a screw press 41 and the lower part of the coagulation tank 33, between the bottom of the mixing tank 5 and the upper part of the storage tank 21, and between the supernatant liquor discharge port 43 of the screw press 41 and the aeration tank 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method and apparatus for producing raw materials for composting of animal manure, sewage and other sludge and food residues using wood fiber and a polymer flocculant while using pH adjusting means.

  Conventionally, various methods and apparatuses for producing composting raw materials have been used, but as shown in the present invention, means for using both wood fibers and a polymer flocculant while adjusting pH I can't find it right now.

Compost (compost, especially compost made from municipal waste and sludge) has been used frequently. Since livestock manure and various sludges contain a large amount of components that can be made into feed or fertilizer by fermentation, many attempts have been made to use them as compost raw materials.
However, the moisture content of the raw material is an important factor in composting.
When the water content is 80% or more, the air permeability is low, and anaerobic fermentation and significant odor and malodor caused by rot occur, and fermentation necessary for producing compost and the like is not performed. Therefore, the water content needs to be 65% or less, but the water content of various sludges is 90% or more and cannot be used as a composting raw material as it is. Therefore, in order to compost various sludge, etc., means to reduce the water content by adding straw, rice husk, sawdust etc. to the sludge is also used, but it will add about 2 to 3 times the amount of sludge Therefore, it is necessary to increase the volume of the fermentation tank by increasing the processing volume. Moreover, imbalance occurs between sludge having a high fermentation rate and slow straw, rice husks, and sawdust, and when composted from this, unripe fertilizer is produced.
On the other hand, various sludges and the like are dried in a high-heat furnace to lower the water content, but the cost is high and it is difficult to obtain a water content of 75% or less.
In addition, there is a means for adding water to the sludge and dehydrating under pressure by utilizing the water absorption of the waste paper. However, in order to reduce the water content to 70% or less, it is necessary to add 40% or more of the waste paper. In addition, an imbalance of the degree of maturity as described above occurs, and the fertilizer is still unripe.
When this immature fertilizer enters the soil, oxygen deficiency and dephosphorization occur in the soil, causing damage to crop cultivation.
On the other hand, the pH value of the dehydrated cake produced is a problem when composting raw materials are produced. In other words, livestock manure, sewage and other sludge and food residues described above often have a low pH value, i.e., are inclined to acidity. Liquid separation is difficult and fermentation microorganisms do not work, which is not preferable as a compost raw material. In order to solve these problems, conventionally, the pH value is adjusted by mixing slaked lime, which is an alkaline substance, into sludge as required. However, this leads to an increase in cost, and there is a need for a means that enables more efficient pH adjustment.
The present invention was invented in order to solve the conventional problems relating to the production of composting raw materials as described above, and was adjusted by adding pH to the sludge and adding a wood fiber and a polymer flocculant and stirring. However, it was developed for the purpose of providing means for obtaining a suitable composting raw material by dehydrating under pressure.

As means for solving the problems, the present invention is constituted by the following manufacturing method and manufacturing apparatus. That is,
1. The first step of aerating the desorbed liquid.
2. A second step in which the composting target is mixed into the desorbed liquid after aeration.
3. A third step in which slaked lime is appropriately added to the mixed liquid as necessary.
4). A fourth step of adding wood fiber to the liquid obtained in the third step and stirring.
5). The fifth step of adding and stirring the polymer flocculant to the substance after the addition of the wood fiber.
6). Sixth step of squeezing and dewatering the material after adding and stirring the polymer flocculant.
7). A seventh step of returning the desorbed liquid obtained in the sixth step to the first step and aeration.
One aspect of the present invention is a method for producing a composting raw material comprising the above steps.
Another aspect of the present invention is:
An aeration tank with an aeration function, a sludge storage tank, and a mixing tank are provided, and a means for introducing the aeration tank and sludge storage tank into the mixing tank is provided. A tank, a mixing tank, a coagulation tank, an additive tank, and a chemical tank are provided, an underwater waste pump with a cutter is installed in the lower part of the storage tank, and an underwater waste pump is installed in the lower part of the mixing tank. In addition, a stirrer having a blade and a motor for rotating a rotating shaft from the upper side to the lower side of the tank is provided, a chemical injection pump is provided in the drug tank, and a blower is provided in the additive tank, respectively. Connect the outlet and the upper part of the mixing tank, the discharge port of the submersible waste pump and the upper part of the coagulation tank, respectively, the blower discharge port and the upper part of the mixing tank, Note: The pump discharge port and the upper part of the coagulation tank are connected by piping, while a screw press machine is provided, the inlet of the screw press machine and the lower part of the coagulation tank are connected by piping, and the bottom of the mixing tank and the upper part of the storage tank are connected by piping. The connected composting object is established by connecting the release port of the screw press machine and the aeration tank by piping, positioning the pump in the middle of each piping as necessary, and providing a power supply control system for each electric device. After adjusting the pH of the mixture, stirring, adding the wood fiber, stirring, further adding the polymer flocculant, stirring, pressing and dewatering to produce a composting raw material, the desorption obtained by this dehydration It was configured to obtain a raw material for composting with low-cost pH adjustment and proper water retention by re-aeration and reuse of the liquid An apparatus for producing compost raw material, characterized.

  According to the present invention, it is possible to adjust the pH of a composting raw material at a low cost, and the wood fiber having a high water absorption and a fermentation time equivalent to the input material, and a highly safe cationic natural polymer Since the flocculant is used for agitation and dehydration treatment, a dehydrated cake with an appropriate water content can be obtained, and this can be used to obtain a new and useful composting raw material that enables composting in a short period of time. Means can be obtained.

Hereinafter, embodiments of the present invention will be described.
In the figure, reference numeral 1 denotes an aeration tank, which is an upper open bottomed cylindrical body. 2 is an air compressor, 3 is an air pipe. The air supply pipe is connected to an air compressor, and the other end descends from above the tank and is located near the bottom of the tank. 4 is a sludge storage tank and 5 is a mixing tank, which has the same configuration as the aeration tank. 6 is a desorption liquid transfer pipe, one end of which is attached to the bottom of the aeration tank, and the other end is lowered from the upper part of the mixing tank and is located in the tank. Desorption liquid water pump 7 is provided at an appropriate position in the desorption liquid transfer pipe.
8 is a sludge transfer pipe, one end of which is attached to the bottom of the sludge storage tank, and the other end is located in the tank through the upper part of the mixing tank. Reference numeral 9 denotes a sludge transfer pump, which is provided at an appropriate place in the sludge transfer pipe.
Reference numeral 10 denotes a mixed liquid transfer pipe, one end of which is connected to the bottom of the mixing tank and the other end is located at the upper part of the storage tank described later. 11 is a mixed liquid transfer pump, and is provided in the mixed liquid transfer pipe. Reference numeral 12 denotes a detachment liquid input pipe, one end of which is located in the tank through the upper part of the aeration tank, and the other end is connected to a detachment liquid discharge port of a screw press machine described later. Desorption liquid transfer pump 13 is provided at an appropriate position of the desorption liquid input pipe. The above is the apparatus unit for pH adjustment.
Next, the apparatus part for manufacturing the composting raw material will be described.
In the figure, reference numeral 21 denotes a storage tank, which is a metal bottomed hollow cylindrical body, and an underwater filth pump 22 with a cutter is installed on the inner bottom thereof. Reference numeral 23 denotes a motor-driven stirrer, which is positioned inside a box provided with a support member (not shown) as appropriate in the upper part of the storage tank. . 26 is a liquid level control electrode rod, the main body part is located in the upper part of a storage tank, and the electrode part is extended toward the downward direction in a storage tank. This liquid level control electrode rod has three stainless steel rods having different lengths, and senses the liquid level position by the liquid level contact at the lower end of each rod and generates a signal.
Reference numeral 27 denotes a mixing tank having the same configuration as the storage tank. An underwater filth pump 28 is installed at the inner bottom of the mixing tank, and a stirrer 29 and a liquid level control electrode rod 30 are similarly provided.
Reference numeral 31 denotes a flow rate adjusting tank, which is a hollow rectangular parallelepiped, and a baffle plate 32 formed by alternately adhering rectangular plate bodies to each other is located on the inner surface thereof. 33 is an agglomeration tank having the same configuration as the mixing tank, and is similarly provided with a stirrer 34 and a liquid level control electrode rod 35.
Reference numeral 36 denotes a medicine tank having a hollow rectangular parallelepiped shape, and a medicine injection pump 37 is positioned above the medicine tank. Reference numeral 38 denotes an additive tank having a shape in which an inverted conical portion is integrally formed at the lower portion of the hollow cylindrical body, and a blower 39 is positioned at the lower portion thereof. Reference numeral 40 denotes a flock tank, which is a hollow rectangular parallelepiped.
41 is a screw press machine. This screw press machine performs continuous dehydration while rotating and rotating the special screw in a cylindrical strainer, and after dehydration, the dehydrated cake is discharged from the discharge port 42 and the desorbed liquid is discharged from the discharge port 43. It is introduced into the aeration tank through the desorbed liquid introduction pipe 12 connected to.

Each of the above devices is connected by piping as follows.
The discharge port of the submersible sludge pump 22 with a cutter and the upper part of the mixing tank 27 are connected by a stirring material transfer pipe 50, and a flow rate adjusting valve 51 is located in the middle. Further, the inside of the storage tank and the inside of the mixing tank are communicated by an overflow pipe 52. The discharge port of the blower and the upper part in the mixing tank are connected by an additive transfer pipe 53. The discharge port of the submersible waste pump 28 in the mixing tank and the flow rate adjusting tank 31 are connected by a primary mixing transfer pipe 55 via a flow rate adjusting valve 54, and the upper part of the mixing tank and the flow rate adjusting tank are connected by an overflow pipe 56. Communicated. The discharge port of the chemical injection pump in the upper part of the chemical tank and the upper part of the coagulation tank are connected by a chemical injection pipe 57. The lower part of the agglomeration tank and the side part of the flock tank are connected by a secondary mixing transfer pipe 58. Further, the mixed liquid transfer pipe 10 enters the storage tank 21 from above, and the mixed liquid is supplied from here. In addition, the upper part of each tank is provided with a seal or lid except for connection points, and power is supplied to each motor and other power-using devices by wiring (not shown), and a control panel for controlling each device ( (Not shown) is provided. Further, for the convenience of illustration, the storage tank position is expressed above the regular position.

Next, the use of the device of the present invention will be described.
First, as preparation, an appropriate amount of fine wood fiber as an additive is stored in an additive tank.
This wood fiber is a fiber obtained by roughly crushing thinned wood or construction waste with a crusher and further crushing it into powder with a fine powder crusher, and is a yellow or tan substance.
In addition, a cationic natural polymer flocculant as a polymer flocculant is stored in the medicine tank.
Next, the prepared detachment liquid is put in the air tank, and an appropriate amount of slaked lime is put in the mixing tank. Sludge is introduced into the sludge storage tank through the sludge inlet pipe, and the tank is aerated by driving the air compressor. This aeration improves the turbidity of the desorbed liquid and stabilizes the liquid. That is, it becomes difficult to anaerobically ferment and it becomes difficult to rot, and the aerobic bacteria in the mixed sludge are activated.
Next, by operating the desorption liquid feed pump 7 and the sludge transfer pump 9, the desorption liquid after aeration is supplied to the mixing tank through the desorption liquid transfer pipe, and the sludge is input to the mixing tank through the sludge transfer pipe. . In this mixing tank, the sludge and the desorbed liquid are mixed by natural convection, and the processed liquid is charged into the storage tank through the mixed liquid transfer pipe by the mixed liquid transfer pump operation. The storage tank is stirred for about 4 to 6 minutes by rotating the blades with a stirrer. In addition, a liquid level control electrode rod for controlling the amount to be charged is provided in the storage tank, and the amount to be charged can be grasped and controlled by a signal from this electrode rod. After stirring for a predetermined time, the agitated material sucked from the lower part of the submersible sludge pump with a cutter is introduced into the tank from the upper part of the mixing tank via the agitated material transfer pipe 50, and the wood fiber in the additive tank is blower 39. Is added to the mixing tank through the additive transfer pipe 53. The wood fiber is added in an amount of about 0.1 to 10% (weight ratio) with respect to the stirred product. Both of these materials are stirred for 1 to 2 minutes by the stirrer 29, sucked by the underwater waste pump 28, passed through the primary mixture transfer pipe and the flow rate adjustment tank, and sent to the agglomeration tank. Note that the mixing tank and the storage tank communicate with each other through the overflow pipe 52, and excess agitated material is returned to the storage tank. A baffle plate is provided in the flow rate adjustment tank to mitigate rapid transition to the agglomeration tank.

The substance after the addition and stirring of the wood fiber is put into the coagulation tank as described above, but the cationic natural polymer coagulant in the chemical tank is sucked up by the chemical injection pump 37 and passes through the chemical injection pipe 57 to the coagulation tank. These are both stirred by the stirrer 4 for about 4 to 5 minutes. By this stirring, flocs are gradually formed. The cationic natural polymer flocculant is used in an amount of about 0.01 to 10% (weight ratio) with respect to the wood fiber-added stirring substance. After the addition and stirring of the flocculant, the floc tank is temporarily stored via the secondary mixing transfer pipe 58, sent to the screw press machine, pressed and dehydrated, and the dehydrated cake is discharged from the discharge port 42, and the desorbed liquid. Is introduced into the aeration tank through the desorbed liquid input pipe 12 connected to the desorbed liquid discharge port 43.
The time required for this compression / dehydration is about 4 to 7 minutes. In addition, the mixing tank and the agglomeration tank are provided with a liquid level control electrode rod like the storage tank, and the storage amount of each tank is managed. Further, an overflow pipe 56 is also communicated between the flow rate adjusting tank and the mixing tank, and the amount of substance in the flow rate adjusting tank is regulated.
The dehydrated cake thus obtained has a moisture content of 65% or less, becomes neutral pH, is composted in the fermentation yard, and can be used as a raw material for compost and feed. That is, the air permeability is improved and fermentation by aerobic bacteria occurs, so the odor is drastically reduced and composting in a short period is possible.
Moisture adjustment is important for composting treatment, and when the water content exceeds 70%, the action of aerobic bacteria causes carbon dioxide to be generated in the process of organic matter decomposition, reducing the function of plant roots and sulfidizing. Hazardous gases such as hydrogen, ammonia and mercaptans are generated, which adversely affects crops and the environment. Therefore, it is necessary to keep the moisture at 65% or less.
Usually, an aeration apparatus is provided in the fermentation yard for promoting composting, and the time for composting can be shortened by supplying external air to promote fermentation and deodorization.
Thus, although a period of 3 to 6 months is required for normal composting, according to the present invention, composting can be completed in 1 to 3 weeks, and the obtained compost fertilizer is applied to agricultural crops. It can be used effectively.

By the means described above, a product separated into a dehydrated liquid and a treated product can be obtained, but this desorbed liquid has significantly reduced BOD (biological oxygen demand) and suspended sludge compared to the input, and nitrogen. A decrease in content and phosphorus content is also observed. In addition, the dehydrated product has a structure in which celluloses having different lengths are entangled vertically and horizontally, and has a feature of high moisture absorption and water absorption and high moisture release.
In the means of the present invention, the order of addition of the wood fiber and the polymer flocculant is important. First, the wood fiber is added to the input material and stirred to form a slurry, and then the polymer flocculant is added and stirred. If this order is reversed, floc (a mixture of water and sludge) is not formed, and the expected dehydration effect cannot be obtained.
The wood fiber used in the present invention is one that has been subjected to sun drying or the like so that the water content is about 15%. When the fiber content of the input is high, the amount of addition is reduced, and when it is low It may be used by adjusting according to the situation such as increasing, and other fiber materials such as disposable chopsticks, old wood chips and straw may be used for wood fiber. Moreover, since livestock manure, sewage sludge, etc. as input materials also vary in composition, the amount of polymer flocculant added is appropriately adjusted.
The screw press used in the final stage desirably has high pressurization, and usually pressurization in the range of 30 kpa to 50 kpa is performed. This press machine separates and discharges the dehydrated cake and the detachment liquid. This detachment liquid contains 10 to 20% nitrogen, 3 to 10% phosphoric acid component, and 5 to 15% potassium component. It can also be used as liquid fertilizer.
Since the pH adjustment level of the slaked lime used in the present invention is lowered in the continuous operation after the initial charging, additional charging is appropriately performed. Usually, automatic feeding is performed using a feeder or the like.
For example, sludge generated by shochu production has a pH of about 3.5, and when the desorbed liquid and this sludge are mixed at a ratio of 50:50, the pH value becomes about 5.1 and additional slaked lime (weight) It is improved to a pH value of about 7 at a ratio of less than 1 percent). The required amount of additional slaked lime varies depending on the mixing ratio of the desorbed liquid with respect to the sludge. About 1 percent additional slaked lime is required for the weaning mixing. Compared to the pH adjustment by simply using slaked lime without using this device, the amount of slaked lime used in the pH adjustment by using this device is about 25%, which greatly reduces the total cost. The aeration tank aerates the desorbed liquid, but this aeration is performed continuously, and the introduced desorbed liquid is continuously transferred to the mixing tank, but the average aeration time received by the introduced desorbed liquid Is 30 minutes or more. In addition, it is desirable to appropriately select the transfer capacity of the desorption liquid feed pump and the sludge transfer pump so that the ratio of the desorption liquid and the sludge charged into the mixing tank is maintained appropriately. Similarly, the mixed liquid transfer pump This also applies to the desorption liquid transfer pump.

Although the present invention has been described above, the present invention uses slaked lime and adjusts the pH value by reusing the detachment liquid, and uses both highly water-absorbing wood fibers and highly safe inorganic polymer flocculants. However, the present invention provides a means for producing a compost raw material having the characteristics and enabling composting in a short period of time.
Conventionally, a wide variety of organic or inorganic polymer flocculants or combinations thereof are used, but some flocculants have the same components as heavy metals and some contain acrylamide substances. When such a flocculant was used, there was a problem that the safety of soil and crops was not ensured when used after composting, but the present invention enabled composting with higher safety. .
In the embodiment, since the flow rate adjustment tank and the flock tank are provided, a smooth process can be obtained by preventing a rapid inflow of the processed material into the aggregation tank and the screw press machine.
Moreover, since the underwater waste pump with a cutter was used in the storage tank, the solid component of the input can be completely crushed and transferred before being transferred to the mixing tank.
The wood fiber and cationic natural polymer flocculant used in the present invention were found as a result of repeated information gathering and research. The wood fiber having high hygroscopicity and high fermentation rate, and the polymer capable of food application. The flocculant has been discovered, and by using these in order, the viscosity of the feed is gradually increased and flocs are formed, resulting in a dehydrated cake whose volume is reduced to about 30% compared to the conventional means, and the desired treatment. Things are obtained.
As described above, according to the present invention, a method for producing a composting raw material having an appropriate pH value and an appropriate water content and an apparatus therefor can be obtained.

  Structure explanatory diagram of the device of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Aeration tank 2 Air compressor 3 Air supply pipe 4 Sludge storage tank 5 Mixing tank 6 Desorption liquid transfer pipe 7 Desorption liquid water pump 8 Sludge transfer pipe 9 Sludge transfer pump 10 Mixture transfer pipe 11 Mixture transfer pump 12 Desorption liquid Input pipe 13 Desorption liquid transfer pump 14 Sludge input pipe 21 Storage tank 22 Underwater filth pump with cutter 23 Stirrer 24 Rotating shaft 25 Blade 26 Liquid level control electrode rod 27 Mixing tank 28 Underwater filth pump 29 Stirrer 30 Liquid level control electrode bar 31 Flow control tank 32 Baffle plate 33 Coagulation tank 34 Stirrer 35 Liquid level control electrode rod 36 Drug tank 37 Chemical injection pump 38 Additive tank 39 Blower 40 Flock tank 41 Screw press machine 42 Dehydrated cake discharge port 43 Desorbed liquid discharge port 44 Drain Valve 45 Drain valve 46 Drain valve 50 Stirring Object transfer pipe 51 flow regulating valve 52 overflow pipe 53 additives transfer line 54 flow regulating valve 55 primary mixing transfer pipe 56 overflow pipe 57 Kusurichukan 58 secondary mixing transfer tube

Claims (2)

1. The first step of aerating the desorbed liquid.
2. A second step in which the composting target is mixed into the desorbed liquid after aeration.
3. A third step in which slaked lime is appropriately added to the mixed liquid as necessary.
4). A fourth step of adding wood fiber to the liquid obtained in the third step and stirring.
5). The fifth step of adding and stirring the polymer flocculant to the substance after the addition of the wood fiber.
6). Sixth step of squeezing and dewatering the material after adding and stirring the polymer flocculant.
7). A seventh step of returning the desorbed liquid obtained in the sixth step to the first step and aeration.
A method for producing a composting raw material comprising the steps described above.   An aeration tank with an aeration function, a sludge storage tank, and a mixing tank are provided, and a means for introducing the aeration tank and sludge storage tank into the mixing tank is provided. A tank, a mixing tank, a coagulation tank, an additive tank, and a chemical tank are provided, an underwater waste pump with a cutter is installed in the lower part of the storage tank, and an underwater waste pump is installed in the lower part of the mixing tank. In addition, a stirrer having a blade and a motor for rotating a rotating shaft from the upper side to the lower side of the tank is provided, a chemical injection pump is provided in the drug tank, and a blower is provided in the additive tank, respectively. While connecting the outlet and the upper part of the mixing tank, the discharge port of the submersible waste pump and the upper part of the coagulation tank, respectively, the blower discharge port and the upper part of the mixing tank, Note: The pump discharge port and the upper part of the coagulation tank are connected by piping, while a screw press machine is provided, the inlet of the screw press machine and the lower part of the coagulation tank are connected by piping, and the bottom of the mixing tank and the upper part of the storage tank are connected by piping The connected composting object is established by connecting the release port of the screw press machine and the aeration tank by piping, positioning the pump in the middle of each piping as necessary, and providing a power supply control system for each electric device. After adjusting the pH of the mixture, stirring, adding the wood fiber, stirring, further adding the polymer flocculant, stirring, pressing and dewatering to produce a composting raw material, the desorption obtained by this dehydration It was constructed so that raw materials for composting with pH adjustment and proper water retention ratio can be obtained at low cost by re-aeration and reuse of the liquid Raw material manufacturing apparatus for composting characterized.

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