JP2001271067A - Method for improving soil of volcanic soil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To design effective utilization of the ash of a fluidized-bed coal boiler of a furnace desulfurization type, and sewage sludge which are conventionally treated as the waste, and further to provide a method for conditioning soil so as to be suitable for growth of a plant by applying the ash and the sewage sludge to volcanic soil hardly having fertilizer-holding power. SOLUTION: An organic fertilizer or a soil conditioner obtained by mixing and granulating the ash of the fluidized-bed coal boiler of a furnace desulfurization type, and the sewage sludge is accumulated on the volcanic soil so as to form 1-3 m thickness to form the conditioned soil rich in fertilizer components and suitable for the growth of the plant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Japan is one of the world's leading volcanic countries, and the volcanic soil on which volcanic products are deposited is widely distributed throughout the country. Volcanic soil is formed from volcanic ash, volcanic rubble, pumice and their weathered materials, etc., and this soil has extremely low ability to retain cations such as ammonia, potassium, calcium, magnesium, which are the nutrients of plants, Many have poor fertility. In the present invention, the volcanic soil is improved by the in-furnace desulfurization type fluidized bed coal boiler ash and sewage sludge, which are conventionally treated as waste and the amount of generation is expected to increase in the future. The purpose of the present invention is to provide an improved soil suitable for soil.

[0002]

2. Description of the Related Art Volcanic soils are formed from volcanic ash, volcanic rocks, pumice stones and their weathered materials. This soil is composed of ammonia, potassium, calcium,
The ability to retain cations such as magnesium is extremely low and is not suitable for plant growth. In other words, even if fertilizers such as ammonium sulfate are applied to increase the fertility of the soil, the cations, which are nutrients, can easily flow out of the water, irrigation water, rainwater, etc. due to the weak cation retention of the soil. .

As a method for improving the volcanic soil, a natural zeolite-based soil improving material has been conventionally used as a method for increasing cation retention of plant nutrients. Recently, there is an example in which artificial zeolite is used as a soil conditioner. In addition, bentonite soil conditioners are also used.

[0004] Natural zeolite-based soil improving materials are natural zeolite as an active ingredient, and are recognized as soil improving materials by the soil enhancement method. This naturally occurring zeolite has a cation exchange capacity (CEC) of 130-150 m
It is about eq / 100g. The cation holding power caused by the CEC can prevent the cations, which are fertilizer nutrients, from flowing out and enhance the fertilizing effect. However, since this natural zeolite is produced by mining and pulverizing a raw ore and, in some cases, firing it, it has a disadvantage of being expensive.

[0005] As described in JP-A-59-86687, an artificial zeolite is one in which an aqueous solution of sodium hydroxide is added to coal ash to cause a heat reaction to synthesize zeolite. Higher than. The CEC value is high, around 250meq / 100g. However, this artificial zeolite promotes the zeolite synthesis reaction,
The disadvantage is that the use of the chemical sodium hydroxide is more expensive than natural zeolites.

[0006] Bentonite soil amendments contain naturally occurring bentonite as an active ingredient, and utilize the swelling properties of bentonite to retain nutrients such as cations dissolved in water and improve the fertilizing effect. Enhance. However, mining
A pulverizing manufacturing process is required, which is also expensive. Further, when the bentonite-based soil conditioner is frequently used, there is a disadvantage that the water permeability of the soil is deteriorated.

[0007] Further, the above-mentioned conventional soil improving materials are not fertilizers but materials for enhancing the fertilizing effect, and it is necessary to apply fertilizers separately from the soil improving materials.

As described above, development of a method for improving volcanic soil widely distributed throughout the country at low cost into soil suitable for plant growth is strongly desired.

[0009]

DISCLOSURE OF THE INVENTION The present invention aims at effectively utilizing in-furnace desulfurization type fluidized bed coal boiler ash and sewage sludge which are conventionally treated as waste, and at the same time, is applied to volcanic ash soil which has almost no fertilizing capacity. In addition, the present invention provides an inexpensive soil improvement method suitable for plant growth.

[0010]

Means for Solving the Problems The present inventors have conducted intensive studies on a method for improving volcanic soil, and as a result, have found that an organic fertilizer obtained by granulating desulfurization type fluid bed coal boiler ash and sewage sludge in a furnace or soil improvement. It has been found that by applying the timber to a volcanic soil, it can be improved to a fertile soil, and the present invention has been completed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The in-furnace desulfurization type fluidized bed coal boiler, sewage sludge and volcanic soil of the present invention will be described.

A fluidized-bed coal boiler is a boiler operated in a state where fine particles called a bed material and fine coal which is a fuel flow in a high-speed combustion gas. In this method, the combustion gas can be desulfurized by supplying fine limestone to the combustion chamber. The reaction is shown below. This is an in-furnace desulfurization type fluidized bed coal boiler. Combustion of sulfur in fuel: S + O ₂ → SO ₂ Reaction of limestone to quicklime: CaCO ₃ → CaO + CO ₂ desulfurization reaction: CaO + SO ₂ 1/2 O ₂ → CaSO ₄ It is sludge generated in a urine treatment facility, and is primary sludge, activated sludge, mixed sludge and digestion sludge of these. There is no particular restriction on the sludge dewatering treatment type such as vacuum dewatering filtration, pressure filtration, centrifugal dewatering, belt press dewatering, screw press dewatering, and multiple disk dewatering.

[0013] Volcanic soil refers to volcanic rock, volcanic ash, pumice, and soils mainly composed of these weathered materials. The particle size of the mixed granulated product of the in-furnace desulfurization type fluidized bed coal boiler ash and sewage sludge is preferably 20 mm or less from the viewpoint of application workability as a soil improvement material.

[0014]

The present invention will be described below in detail with reference to examples. As the volcanic ash soil, a wilderness which is an unsuitable stratum for plant growth shown in FIG. 1 was selected. At this point, there are volcanoes and coasts nearby, and at a depth of about 5 m or more from the surface, layers composed mainly of sand and layers of volcanic products are formed alternately. At a depth of 5 m below the surface, a very thin surface soil (approximately 0.1-0.5 m) is formed underneath, and a pumice fall layer due to a recent volcanic eruption is formed (approximately 0.5-2.0 m).

Fluid bed coal boiler ash containing 4% or more quicklime in a furnace and dry sewage sludge having a moisture content of 45% (activated sewage sludge obtained from sewage treatment plant in A city, Hokkaido A) After mixing well at 1000: 100, water is added at a weight ratio of 40
0 Addition, granulation with backflow high-speed granulator, particle size 1.0-9.0mm
Got something. This was used in the examples.

In Example 1, a granulated material having a thickness of 3 m was deposited on the volcanic ash soil shown in FIG. 1 with a bulldozer. Its structure is shown in FIG. In Example 2, the volcanic ash soil shown in FIG. 1 was peeled off at a depth of 1 m, and the above-mentioned granulated material at a depth of 3 m was mixed with a civil engineering stabilizer and returned to the peeled off portion. The structure is shown in FIG.

In Example 3, the volcanic ash soil shown in FIG. 1 was peeled off at a depth of 1 m, and this was thoroughly mixed with the above-mentioned granulated material at a depth of 1 m, and returned to the peeled portion. Next, the 1 m depth was peeled off, mixed with the granulated material, and returned to the peeled portion. Finally, this operation was repeated once more to obtain a structure in which the surface layer had a higher content of granules. FIG. 4 shows the structure.

The original volcanic ash soil was used as a comparative example. This and the improved soil of Examples 1 to 3 were sprayed with grass seeds (variety: Hokuou), and a growth test of the grass was performed. As a result, the yield was measured. An increase in yield was confirmed. The results are shown in Table 1.

[0019]

[Table 1]

[0020]

According to the technology of the present invention, the granules produced from in-furnace desulfurization type fluidized bed coal boiler ash and sewage sludge, which are wastes, are deposited in layers on volcanic soil, or To improve fertile soil suitable for plant growth by contributing to the conservation of the environment through effective use of waste, and at the same time to provide an inexpensive soil improvement method for agriculture and forestry. High technology.

[Brief description of the drawings]

FIG. 1 is a diagram showing a stratum of volcanic ash soil.

FIG. 2 is a diagram showing a soil structure of Example 1.

FIG. 3 is a diagram showing a soil structure of Example 2.

FIG. 4 is a view showing a soil structure according to a third embodiment.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (for reference) // B09B 3/00 ZAB B09B 3/00 301M 301 (C05G 1/00 (C05G 1/00 C05D 3:02 C05D 3: 02 C05F 7:00) C05F 7:00) C09K 101: 00 C09K 101: 00 B09B 3/00 ZAB (72) Inventor Minoru Matsubara 143 Yufutsu, Tomakomai City, Hokkaido F Term in the Yufutsu Mill of Nippon Paper Co., Ltd. (Reference) 2B022 AA05 BA02 BA05 BA13 BB01 DA19 4D004 AA02 AA36 AC04 BA04 BA10 CA14 CA15 CB50 4D059 AA02 AA04 AA05 AA23 BE14 BE15 BE16 BE26 BE27 BE38 BK09 CC01 CC10 DA64 4H026 AA01 AA18 4H061 AA01 GG04 GG07 CG07 LLCC

Claims (4)

[Claims] 1. An organic fertilizer or a soil improving material obtained by mixing and granulating an in-furnace desulfurization type fluidized bed coal boiler ash and sewage sludge in a thickness of 1 to 3 m on a volcanic soil to form a fertilizer component. A soil improvement method comprising forming an improved soil suitable for growing rich plants. 2. Peeling off 1 m from the surface layer of the volcanic soil,
And an organic fertilizer or soil improvement material obtained by mixing and granulating the fluidized-bed coal boiler ash and sewage sludge in a furnace desulfurization method.
a soil thickness of m with a thickness of m, which is then deposited on a portion where the surface layer has been peeled off to form an improved soil which is rich in fertilizer components and suitable for growing plants. 3. Peeling off 1 m from the surface layer of the volcanic soil,
This is mixed with an in-furnace desulfurization type fluidized bed coal boiler ash and sewage sludge, which are mixed and granulated with an organic fertilizer or a soil improver having a thickness of 1 m, and then deposited on the portion where the surface layer has been peeled off.
A soil improvement method comprising repeating this one to three times to form an improved soil suitable for growing a plant devised so that the closer to the surface layer, the richer the fertilizer component is. 4. The soil improvement method according to claim 1, wherein the main component of the volcanic soil is volcanic ash and / or volcanic rubble and / or pumice and / or weathered material thereof.