JP4754065B2 - Plant growth base materials - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plant growth base material which is created on the top or slope of embankments or cuts for greening on new roads and residential land development sites.
[0002]
[Prior art]
Conventionally, soil such as topsoil or weathered soil, and aggregates of soil particles obtained by adding and mixing aggregates with soil as a material for plant growth on which plant seeds are seeded or planted (groups) Are used.
[0003]
By the way, sludge that has been disposed of as industrial waste, such as sludge that has been scooped up from a sedimentation basin at a water treatment plant or sludge generated from a muddy water treatment facility such as muddy water used in tunnel excavation work, It is known that most (about 99%) consists of fine clay particles.
[0004]
Therefore, from the viewpoint of such sludge reuse, it is conceivable to use sludge as a plant growth base material.
[0005]
However, the porosity of the plant growth base material containing sludge as a component is very small, not far from about 60%, which is considered to be suitable for vegetation. For this reason, the plant growth base made of sludge, that is, clay particles, has a problem that the gap and drainage performance necessary for plant root respiration cannot be ensured.
[0006]
In order to increase the porosity, this problem is caused by adding aggregate agents to the sludge and mixing them to change the clay particles which are the components of the sludge into aggregates, and using these aggregates as plant growth base materials. It can be solved.
[0007]
However, the agglomeration rate, which is the rate at which clay particles are aggregated by the addition of aggregates, is relatively low, and when a flocculant is added to sludge treatment, There is very little residual amount of clay particles left untreated. For this reason, those obtained by adding and mixing aggregates are not suitable for plant growth base materials. In addition, the aggregate of clay particles is fragile unlike the aggregate, and in this respect, it is not suitable for a plant growth base material.
[0008]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a plant growth base material that contributes to effective utilization of sludge.
[0009]
[Means for Solving the Problems]
The plant growth base material according to the present invention is a mixture in which dry sludge and wood chips having a size corresponding to the size of a toothpick or chopstick are mixed at a volume ratio of 1: 1, or dry sludge and soil. A mixture in which wood chips having a size corresponding to the size of a toothpick or chopstick are mixed at a volume ratio of 1: 1, for example, a mixed volume ratio of dry sludge, soil and wood chips is 1: 1: 2 or It consists of a mixture that is 2: 1: 3, or a mixture that is respectively mixed in these volume ratios and to which a granule is added.
[0010]
【The invention's effect】
According to the present invention, by mixing dry sludge with soil, such as equal volume of topsoil or weathered soil made of soil particles having a particle size different from that of clay particles, or wood chips with different shapes. Or, by mixing dry sludge and soil with wood chips having a volume equal to the sum of these volumes, there is a gap between the clay particles constituting the dry sludge or its aggregated particles and the soil or wood chips. As a result, a plant growth base material having a porosity of about 60% suitable for vegetation can be obtained, and sludge can be effectively used.
[0011]
The wood chip also serves to reinforce the erosion resistance because it also functions to reinforce the plant growth base.
[0012]
In the mixture with the addition of the aggregate agent, the aggregate agent aggregates the clay particles in the dried sludge, the residual clay particles remaining after the aggregation, and the soil particles constituting the soil. A plant growth base having The added nodule agent also has a function of connecting the nodule to each other and improves the erosion resistance of the plant growth base. Suitable for building up plant growth base.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The plant growth base material according to the present invention comprises a mixture in which dried sludge and soil are mixed at a volume ratio of 1: 1 (first example).
[0014]
The dried sludge is obtained by finely pulverizing a plate-shaped so-called dehydrated cake obtained by dewatering hydrous sludge generated from a water purification plant or muddy water treatment facility with a filter press (not shown).
[0015]
The dried sludge includes those to which a flocculant is added in advance for the treatment prior to dewatering by the filter press.
[0016]
The soil is made of topsoil or weathered soil.
[0017]
The dried sludge and the soil can be mixed using, for example, a plant mixer (not shown). By mixing, the clay particles which are the components of the dried sludge are mixed with the soil particles which are the components of the soil having a different particle size. This creates voids between the clay particles.
[0018]
According to an experiment, when the mixing ratio of clay particles in the mixture is 50%, that is, when the dry sludge volume: the soil volume = 1: 1, the porosity of the mixture is suitable for vegetation. It was almost 60%. For reference, the experimental values of the porosity of the mixture when the mixing ratio of the clay particles was 25%, 75%, and 100% were about 50%, 80%, and 90%, respectively.
[0019]
As the plant growth base material, a mixture obtained by adding and mixing a water-soluble polymer such as polyacrylamide into the dried sludge and the soil in the volume ratio being mixed. The aggregating agent is an aqueous solution having a concentration of 0.2% from the viewpoints of its economic efficiency and its effect. The mixture containing the aggregating agent has a sponge shape.
[0020]
The aggregate is obtained by collecting clay particles in the dried sludge, non-aggregated residual viscous particles when the dried sludge is treated with a flocculant, and soil soil particles. Large aggregates are connected and these aggregates are interconnected. For this reason, the plant growth base material containing aggregates provides better voids for plant growth and imparts less erosion, ie, higher erosion resistance, to the plant growth base. Therefore, this material is particularly suitable for building a plant growth base on the slope.
[0021]
Instead of the soil, the mixture obtained by mixing the dried sludge with an equal volume of wood chips can be used as the plant growth base material (second example).
[0022]
The wood chips having a different size and shape from the clay particles also serve to form voids between the clay particles of the dried sludge. The wood chip has, for example, the size of a toothpick or disposable chopsticks.
[0023]
Thus, the mixture obtained by mixing the dried sludge and the wood chip at a volume ratio of 1: 1 also provides a plant growth base material having a porosity of approximately 60%. In this material, the entanglement between the dried sludge and the wood chips and the entanglement between the wood chips reinforces the plant growth base and enhances the erosion resistance.
[0024]
Similarly, the mixture containing the wood chips can be obtained by adding the aggregate agent, whereby the clay particles or the residual clay particles are aggregated and connected to each other. Can be planned.
[0025]
The plant growth base material may be made of a mixture in which the dry mud and soil and the wood chip are mixed at a volume ratio of 1: 1 (third example).
[0026]
More specifically, it can be set as a mixed volume ratio of dry mud: soil: wood chips = 1: 1: 2. In this example, the amount of wood chips corresponds to the sum of the amount of the same volume as the dry mud and the amount of the same volume as the soil. Therefore, the plant growth base material composed of this mixture is substantially equivalent to a mixture of the mixtures of the two examples (the first example and the second example) that do not contain the aggregate agent. It has the same properties as the two examples.
[0027]
As another specific example, a mixed volume ratio of dry mud: soil: wood chips = 2: 1: 3 can be used. According to this, a larger amount of dry mud can be used.
[0028]
Also about the said mixture containing 3 persons, dry mud, soil, and a wood chip, it can be set as the mixture containing the aggregate agent added on the same conditions as mentioned above. In the plant growth base material comprising the mixture containing the aggregate, the clay particles, the residual clay particles, and the soil particles are aggregated in the same manner as the mixture in the first example including the aggregate. It acts to connect each other.
[0029]
In forming the mixture, water, plant seeds, fertilizer and the like are added as necessary.
[0030]
The mixture, that is, the plant growth base material, for example, is placed on a so-called high-speed belt conveyor having a conveyor belt capable of rotating at high speed, and is scattered from the end of the belt conveyor onto the planned growth base of the plant growth base and dispersed. Thus, a plant growth base having a desired thickness and a desired width can be created.

Claims (8)

A plant growth base material comprising a mixture of dried sludge and wood chips having a size corresponding to the size of a toothpick or chopsticks in a volume ratio of 1: 1. A plant growth base material comprising a mixture of dried sludge and soil and wood chips having a size corresponding to the size of a toothpick or chopsticks in a volume ratio of 1: 1. The plant growth base material according to claim 2, wherein a mixed volume ratio of the dried sludge, the soil, and the wood chips is 1: 1: 2. The plant growth base material according to claim 2, wherein a mixed volume ratio of the dried sludge, the soil, and the wood chips is 2: 1: 3. A plant growth base material comprising a mixture in which dried sludge and wood chips having a size corresponding to the size of a toothpick or chopstick are mixed at a volume ratio of 1: 1 and a granule is added. A plant growth base material comprising a mixture of dried sludge and soil and wood chips having a size corresponding to the size of a toothpick or split chopsticks in a volume ratio of 1: 1 and to which a nodule is added. The plant growth base material according to claim 6, wherein a mixed volume ratio of the dried sludge, the soil, and the wood chips is 1: 1: 2. The plant growth base material according to claim 6, wherein a mixed volume ratio of the dried sludge, the soil, and the wood chips is 2: 1: 3.