JPH10291877A - Production method of organic sludge fertilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an org. fertilizer containing a desired component from an org. waste at a low cost. SOLUTION: An org. sludge fertilizer is produced by dehydrating an org. sludge to make a dehydrated sludge having a 50-85 wt.% (wet base) water content, charging the obtained dehydrated sludge to a dryer 4 having simultaneously a mixing function and a granulating function, also charging zeolite, an additional fertilizer component, a pH adjusting component, a deodorant and/or a soil conditioner as an additional component, mixing the hydrated sludge and the additional components in the dryer 4, drying and granulating the mixture. An working temp. in a drying operation is suitably within the range of 60-80 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an organic sludge fertilizer from organic sludge such as sewage sludge, rural settlement drainage sludge, septic tank sludge, human waste sludge, and the like. In the following description, the water content means% by weight on a wet basis.

[0002]

2. Description of the Related Art The above-mentioned organic sludge has been conventionally used as a fertilizer in the form of a dewatered cake, a dried cake, compost or the like. However, the dehydrated cake was bulky and rich in moisture, and was difficult to handle due to its strong adhesion. The dried cake has a low water content and is easy to handle, but has a problem of preventing generation of odor during drying. The compost is produced by fermentation of microorganisms and is excellent as a fertilizer, but has a problem in that the processing cost is large. In addition, there was a disadvantage that it was difficult to adjust the balance of the three elements of fertilizer in common.

In order to solve the above problem, it has been proposed to add zeolite or the like to organic sludge and process it into a required solid organic sludge fertilizer. For example, Japanese Patent Publication No. 3-69600 describes a sludge treatment method in which zeolite and quick lime are added to sludge in a septic tank or the like, further mixed with stirring, and then dried and granulated. Also, Japanese Patent Application Laid-Open Nos. Sho 62-167281 and
No. 1380 describes a method for producing a fertilizer composition in which sludge is dried or processed into compost and then zeolite or the like is added.

[0004]

[Problems to be solved by the invention]
In the sludge treatment method described in No. 9600, the water content of the final treated product is as high as 55 to 70% (the sewage sludge fertilizer moisture content standard recommended by the National Agricultural Cooperative Association of Japan is 30% or less),
Further, since a large amount of quicklime is used, the content of slaked lime, which is a reaction product, is high, and it is difficult to obtain a desired component composition. Also, JP-A-62-167281 and JP-A-64-1138.
The production method of the fertilizer composition described in No. 0 publication has a problem that the water content of the processed sludge is too low and the additive component is not easily formed and integrated,
Separately, various equipment such as a granulator is required, and the cost tends to be high. The present invention relates to an organic sludge fertilizer which is prepared by adding a required additive component to an organic sludge as a main raw material, mixing the main raw material and each of the additional components, and forming a uniform and easy-to-use homogeneous sludge. Was completed as a result of studying a method for easily manufacturing the same at low cost.

[0005]

That is, the present invention provides an organic sludge having a water content of 50 to solve the above-mentioned problems.
Dewatered sludge by dewatering to ~ 85% by weight (wet amount basis), and mixing the obtained dewatered sludge into a dryer having both a granulating function and adding zeolite, an additional fertilizer component, a pH adjusting component, Provided is a method for producing an organic sludge fertilizer, which comprises adding a deodorant and / or a soil conditioner, mixing a dehydrated sludge and an additive component in a dryer, drying, and granulating. In the production method of the present invention, the temperature of the drying operation is preferably in the range of 60 to 80 ° C.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described with reference to the drawings and embodiments. FIG. 1 is a flow sheet showing an embodiment of the present invention. Organic raw material sludge, such as sewage sludge, rural settlement drainage sludge, septic tank sludge, human waste sludge, etc., which is a raw material of fertilizer, is dehydrated into dewatered sludge and stored in the dewatered sludge hopper 1. The water content of the dewatered sludge is preferably 50 to 85%. If the water content is too low, it is difficult to uniformly mix the dehydrated sludge with the zeolite, the additional fertilizer component, the pH adjusting component, the deodorant, and / or the soil conditioner to be added as an additional component, and molding and integration are difficult. It is not preferable because it is difficult to perform. If the water content is too high, it will adhere to the mixer, making the operation difficult and increasing the energy consumption. There is no particular limitation on the dehydration method, and an optimal means can be selected and implemented depending on the characteristics of the organic raw material sludge, the operating environment, and the like. A required amount of the stored dewatered sludge is continuously or intermittently extracted according to a process using a screw feeder 2 installed below the dehydration sludge hopper 1. It is supplied to a dryer 4 having a granulating function.

[0007] The dryer 4 can be appropriately selected depending on the installation conditions, whether it is a continuous type or a batch type, as long as it is a device capable of performing operations of mixing, drying and granulation of adherent solids. . In particular, a dryer that can be operated at a temperature of 60 to 80 ° C. under reduced pressure can be preferably used. This is because in this temperature range, a sterilizing effect is achieved while preventing denaturation of proteins in the sludge. The decompression operation has the advantage of improving drying efficiency and reducing energy consumption. Specifically, as a mixing granulation dryer, a container fixed type stirring type solid mixer such as a horizontal axis paddle type mixing machine with a heating jacket, or a container rotating type inclined vertical type stirring mixer is preferably used. It is not limited to.

A flow meter or an integrated flow meter 5 is attached to the discharge pipe of the dewatered sludge supply pump 3. When the dewatered sludge is continuously supplied, the supply amount per time is adjusted by controlling the rotation speed of the dewatered sludge supply pump 3. Then, in the case of batch operation, when the predetermined supply amount is reached, the pump 3 is stopped. further,
In any case, a level meter is preferably attached to the dewatered sludge hopper 1 so that the rotation speed of the screw feeder 2 can be adjusted so that the amount of sludge in the dewatered sludge hopper 1 can be kept within the operable range.

In the production method of the present invention, a continuous type is used simultaneously with the dewatered sludge, a batch type is used simultaneously with the input of the dewatered sludge, or before or after the input of the dehydrated sludge, from the storage hopper 6 for each additive component, or Various suitable components such as zeolite, additional fertilizer component, pH
The adjusting component, the deodorant, and / or the soil conditioner are charged into the dryer 4, and the dewatered sludge is mixed with each component in the dryer 4, dried, and granulated. In this embodiment, a pneumatic conveyor is used to transport the additional components. 8 is a rotary feeder, 9 is a carrier gas supply compressor, and 10 is a bag filter at the outlet of the carrier gas.

[0010] The above-mentioned additive components are appropriately selected for the purpose of demands of customers, quality improvement and efficiency of processing operations, and necessary amounts are added. Specific examples of the additional component include zeolite, quicklime, slaked lime, pulverized coal, potassium chloride, sodium phosphate, potassium phosphate, and powdered urea. Among these additional components, zeolite has a cation exchange group and ion-exchanges phosphorus or the like to provide a long-term fertilizing effect. In addition, other than soil improvement effects such as air permeability,
Since it absorbs odor components such as ammonia, it is also effective for odor control during and after fertilization. Also, quicklime is
Used as a fertilizer for acidic soils, it also has the effect of increasing the drying rate due to the exothermic reaction with water. Slaked lime can also be used. Pulverized coal can contribute to carbon replenishment and odor control when the C / N ratio is small. Potassium chloride, sodium phosphate, potassium phosphate, powdered urea and the like are used for adjusting fertilizer components.

[0011]

EXAMPLES The present invention will be specifically described with reference to examples. The sewage sludge was converted into dehydrated sludge having a water content of 76.7% using a belt press. 35 kg of this dewatered sludge was used together with zeolite (Nitto Zeolite No. 2: manufactured by Nitto Powder Chemical Co., Ltd.) together with a vacuum batch dryer (R08vac: Nippon Eirich Co., Ltd.) which was used as a dryer having a mixing and granulating function.
Manufactured), and a lawn fertilizer having a particle size of 4 mm was mixed, dried and granulated for the purpose of granulation. The water content of the mixture was 58.3%. The temperature of the contents of the dryer is 60 ° C and the pressure is 600 mmb.
The mixture was maintained at ar and mixed, dried and granulated for 2.05 hours to produce an organic sludge fertilizer. The obtained organic sludge fertilizer was 26.18 kg and had a particle diameter of 4 mm or more of 42.9.
Weight%, 47.1% or less 57.1%, bulk density 0.66
Met. In addition, during these operations, a three-point comparison odor bag method (notified by the Environment Agency in 92
The odor concentration of the exhaust gas measured according to
740.

[0012]

According to the present invention, mixing, drying and granulation of the dehydrated sludge and each additive component are performed simultaneously. The resulting product is homogeneous because each component is efficiently and thoroughly mixed and dried under the same conditions and with a moderate moisture content. In addition, since the components are mixed with each other, mixed, dried and molded, a synergistic fertilizing effect can be expected. In the production method of the present invention, any necessary additive components can be added in any ratio unless there is a special reason. For example, zeolite also has the effect of suppressing odor emission during operation.
Since each operation is performed with an appropriate water content using a multi-function device, dewatered sludge does not adhere to the device during the manufacturing process, making operation difficult, and the apparent water content of the mixture decreases. Since the slurry does not form a slurry, the heat transfer surface increases, and the drying efficiency increases, so that the energy consumption can be reduced. As the fertilizer mixes, dries and granulates the components according to the conditions and requirements of the place of use, sludge fertilizer can be obtained economically and with high added value.

[Brief description of the drawings]

FIG. 1 is a flow sheet showing an embodiment of the present invention.

[Explanation of symbols]

1: Dewatered sludge hopper 2: Screw feeder 3: Dewatered sludge supply pump 4: Dryer having mixing / granulation function 5: (Integrated) flow meter 6: Additive component storage hopper 7: Dryer inside vacuum dryer 8: Rotary feeder 9 : Carrier gas supply compressor 10: Bag filter

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C05G 3/04 C05G 3/04 5/00 5/00

Claims (2)

[Claims] 1. An organic sludge is dehydrated to a dewatered sludge having a water content of 50 to 85% by weight (wet amount basis), and the obtained dewatered sludge is mixed and poured into a dryer having a granulating function. Zeolite, additional fertilizer component, pH
The adjusting component, the deodorant, and / or the soil conditioner are added, and the dehydrated sludge and the additional component are mixed in the dryer,
A method for producing an organic sludge fertilizer, comprising drying and granulating. 2. The method for producing an organic sludge fertilizer according to claim 1, wherein the drying operation is carried out within a range of 60 to 80 ° C.