JP2011168957A - Rainwater storage tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an underground storage tank which has a rainwater purifying action and which enables the rainwater stored under the ground to gradually permeate the ground. <P>SOLUTION: This rainwater storage tank includes: a storage section 10 for storing the rainwater, which formed under the ground; a glassy foam 40 which is constituted by heating and burning glass powder, obtained by crushing a glassy waste material with a particle diameter of 1-200 mm, embedded in a part or the whole of the inside of the storage section 10, to a softening point or above and subsequently cooling the glass powder; and an impermeable plastic sheet 20 for covering a bottom surface of the storage section 10 and a lateral lower area thereof. This enables the rainwater in the storage section 10 to be stored in the state of being alkalified to pH9 or more, and prevents the corrosion of the rainwater. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a rainwater storage tank installed in a basement such as a garden of a residential land, a park, a parking lot, or a site.

  Conventionally, as an underground storage tank of rainwater, there exists an underground storage tank disclosed by patent document 1, for example. Such an underground storage tank forms a storage part for storing rainwater in the ground, and has a water-permeable / permeable sheet having a water-permeable part and a water-permeable surface on the top surface, side surface and bottom surface from the overflow part of the storage part. Attached.

However, the underground storage tank has a synthetic resin filler in which four support legs are provided at the four corners of a rectangular beam body, and therefore has no rainwater purification action (patent) Reference 1 Paragraph number “0037” (see FIG. 6). For this reason, the internal water is easily corroded and the filler is easily contaminated, which causes a problem that the filler needs to be replaced every two to three years. In addition, there is a problem in that rainwater cannot penetrate into the ground unless rainwater is stored up to the overflow portion. Furthermore, when the underground storage tank is discarded, there is a problem that it is necessary to backfill with soil after removing the internal filler.
JP 2009-52366 A

  Therefore, the present invention has been made in view of these problems, and it is an object of the present invention to provide an underground storage tank that has a rainwater purification action and can gradually infiltrate rainwater stored underground. Objective.

  In order to achieve the above-mentioned object, the present invention employs the following means.

The rainwater storage tank according to the present invention,
A storage part for storing rainwater formed in the ground and a glass powder obtained by pulverizing a glassy waste material having a particle size of 1 mm to 200 mm embedded in a part or all of the storage part was heated and fired above the softening point. After cooling, a vitreous foam formed by cooling,
A water-impermeable first sheet member that covers a bottom surface and a lateral lower region of the reservoir, and
The rainwater in the reservoir can be alkalized to pH 9 or higher.

  The present invention has a storage part in the ground, and a glassy foam formed by cooling the glass powder obtained by pulverizing the vitreous waste material by heating and baking it above the softening point is embedded in the storage part. is there. Rainwater is stored by allowing rainwater to penetrate into the bubbles of the embedded glassy foam and retaining the rainwater in the gaps between the glassy foams. That is, the glassy foam has a role as a water retention material. Therefore, if the non-permeable first sheet is covered only by the depth necessary for effectively using the bottom surface and the lateral lower area of the reservoir with a pump or the like, the lateral upper area of the reservoir is covered with the sheet. It has a function as a storage tank without covering with. Moreover, since it has rain water with low mobility which penetrated into the bubbles of the vitreous foam and rain water with high fluidity stored between the vitreous foam, the rain water gradually permeates into the soil. That is, immediately after it rains, rainwater penetrates between the glassy foams and into the bubbles. And the water with relatively high fluidity stored between the glassy foams penetrates into the ground, and then rainwater in the bubbles of the glassy foam penetrates into the soil according to the dry state. . Furthermore, since the water-impermeable first sheet member is disposed on the bottom surface of the storage unit and the laterally lower region, rainwater can be stored completely inside the first sheet member below the storage unit. The rainwater collected in this lower layer rises to the upper surface between the vitreous foams embedded by capillarity and bubbles, so that it has the ability to permeate the rainwater into the ground until the rainwater accumulated in the storage part is completely eliminated. If a pump is installed, rainwater collected in the lower layer can be used for watering gardens, vegetable gardens, etc., used for washing gardens, houses, cars, etc., or used as cooling water for air conditioners, etc. it can. Further, since the vitreous foam itself has a purifying action, even if some soil advances to the vitreous foam side, the rainwater collected in the lower layer by the filtration action becomes rainwater that is highly transparent and purified. Furthermore, since the vitreous foam is alkaline, rainwater stored in the rainwater storage tank is alkalized to pH 9 or more. Therefore, corrosion of rainwater can be prevented and propagation of bacteria such as Escherichia coli can be suppressed. Further, when discarded, the vitreous foam is a recycled product of glass, so that it can be disposed as soil as it is.

  Moreover, you may provide the water-permeable or water-permeable 2nd sheet | seat member which covers the side upper area | region of the said storage part as a rainwater storage tank which concerns on this invention. By adopting such a configuration, if the second sheet member having a slow water permeation speed is used, it is possible to further adjust the speed at which rainwater accumulated in the glassy foam in the upper region of the reservoir penetrates the soil. it can. Further, it is possible to prevent the soil from entering the inside from the side.

Further, as the rainwater storage tank according to the present invention, a third sheet member having water permeability or water permeability may be laid on the upper surface of the embedded glassy foam. By adopting such a configuration, it is possible to prevent the soil from advancing to the vitreous foam side from the embankment placed on the upper surface of the rainwater storage tank.

  Moreover, as a rainwater storage tank which concerns on this invention, it is good also as a thing whose upper plane area of the said storage part is larger than a lower plane area. The rainwater storage tank according to the present invention has an upper portion whose plane area is larger than the lower plane area, and even if it is disposed so as to extend in the lateral direction, rainwater can be retained by vitreous foam. The part can also have a rainwater storage function. Moreover, since the area which touches the underground surface increases, rainwater can be penetrated into the ground more efficiently.

  Moreover, as a rainwater storage tank which concerns on this invention, the said glassy foam may contain 5-25 weight% of calcium oxide with respect to the total weight. By adopting such a configuration, it becomes possible to alkalin rainwater and more reliably maintain the Langlia coefficient for a long time.

  Further, as the rainwater storage tank according to the present invention, the glassy foam may have a water absorption rate of 30% or more. By using a glassy foam having such a water absorption rate, rainwater can be retained more efficiently.

  ADVANTAGE OF THE INVENTION According to the invention which concerns on this invention, it can be set as an underground storage tank which has the effect of hold | maintaining the rainwater stored underground in the underground water tank while having a rainwater purification effect | action. Moreover, when discarding an underground storage tank, it can be set as the underground storage tank which can be discarded without removing an internal filler.

It is front sectional drawing which shows the rainwater storage tank 100 which concerns on the 1st Embodiment of this invention. It is front sectional drawing which shows the modification of the rainwater storage tank 100 which concerns on the 1st Embodiment of this invention. It is front sectional drawing which shows the rainwater storage tank 100 which concerns on the 2nd Embodiment of this invention. It is front sectional drawing which shows the rainwater storage tank 100 which concerns on the 3rd Embodiment of this invention. It is front sectional drawing which shows the rainwater storage tank 100 which concerns on the 4th Embodiment of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. Note that the embodiments and drawings described below exemplify a part of the embodiments of the present invention, and are not used for the purpose of limiting to these configurations. Moreover, the same or similar code | symbol is attached | subjected to the corresponding component in each figure.

  Here, in describing the embodiment for carrying out the present invention, the correspondence between the components of the present embodiment and the components of the present invention will be clarified. The 1st storage part 12 and the 2nd storage part 13 in this Embodiment are equivalent to a storage part, the water-impermeable plastic sheet 20 is equivalent to a 1st sheet member, and a water-permeable or water-permeable sheet 23 is a 2nd sheet member. The cover sheet 25 corresponds to the third sheet member. Other terms are common to the claims.

(First embodiment)
FIG. 1 is a front sectional view showing an outline of the configuration of the rainwater storage tank 100 according to the first embodiment. The rainwater storage tank 100 is provided in a basement such as a residential land garden, a park, a parking lot, etc., and as shown in FIG. 1, a storage unit 10 that stores rainwater, and a bottom surface and a lateral lower region of the storage unit 10. A water-impermeable plastic sheet 20 disposed so as to cover the water, a pumping-up pump device 30 for pumping up stored rainwater, and a vitreous foam 40 embedded in the storage unit 10.

The storage unit 10 is formed by excavating the ground to make a hole. The shape of the hole to be excavated is not particularly limited. In this Embodiment, the storage part 10 is formed in a rectangular parallelepiped, and the intake part 11 which one part was dug down one step so that the intake port 33 of the pump apparatus 30 demonstrated later can be arrange | positioned is formed. However, it is the granular vitreous foam 40 that is disposed in the rainwater storage tank 100 of the present invention, and since it is simply embedded as described later, the degree of freedom with respect to the shape of the storage portion 10 is high. The shape of the reservoir 10 is not particularly limited, and may be any shape such as a polygon or a circle in addition to a circle or an ellipse in plan view. Further, the bottom surface need not be a horizontal plane, and the bottom surface may be provided obliquely as shown in FIG. If such a bottom surface is adopted, rainwater flows downward, so there is no need to provide a water intake portion 11 formed partly lower.

  The water-impermeable plastic sheet 20 is disposed so as to cover the bottom surface and the lower region of the side surface of the storage unit 10. Therefore, at the height of the water-impermeable plastic sheet 20 disposed on the side surface, rainwater is completely stored inside, and the first storage portion 12 (a portion hatched diagonally) is formed. The height of the water-impermeable plastic sheet 20 is not particularly limited, and can be appropriately set according to the amount of rainwater to be stored, the amount of rainwater permeated into the ground, and the like. As the material of the water-impermeable plastic sheet, a vinyl chloride sheet, a polyethylene sheet, a polypropylene sheet or the like is used, but is not limited thereto.

  The pump 30 is connected to the electric pump 31 for pumping rainwater accumulated in the first reservoir 12, the water intake 33 disposed in the water intake 11, the electric pump 31 and the water intake 33, and passes through the rainwater. And a water intake pipe 32. The rainwater pumped up by the pump 30 can be used for watering a garden or a vegetable garden, or used for cleaning a garden, a house, a car, or the like. The electric pump 31 is not necessarily electric and may be manually operated.

  The vitreous foam 40 is produced by heating and baking glass powder obtained by pulverizing a vitreous waste material to a temperature above the softening point and then cooling. The particle size is preferably 1 mm to 200 mm. If it is less than 1 mm, the flow of rainwater will be poor, and if it is more than 200 mm, the gap between the glassy foams will be too large, the rainwater storage performance between the gaps will be reduced, and soil will easily flow in. Therefore, it is not preferable. More preferably, it is 5 mm-100 mm. The bubbles may be closed-cell type or open-cell type. If an open-cell glassy foam having a water absorption rate of 30% or more is used, the water retention rate becomes high and the rainwater storage property becomes high. Moreover, you may contain 5 to 25 weight% of calcium oxide as a component of the glassy foam 40 with respect to the total weight. By employing the vitreous foam 40 having such a configuration, the rainwater that has passed can be maintained at a pH of 9 or more for a long period of time, and rainwater having a high Langeria coefficient can be stored.

  After the vitreous foam 40 is laid on the first storage portion 12, it is spread on the second storage portion 13 indicated by the phantom line 50 in FIG. Therefore, above the water-impermeable plastic sheet 20, the vitreous foam 40 is spread in a state of being in direct contact with the soil. Thereafter, the embankment is backfilled, and the underground storage tank 100 is built in the ground. The depth of the embankment may be 10 cm or more, but it is preferable to set the depth to about 10 cm to 50 cm in consideration of the penetration of rainwater.

  The rainwater storage tank 100 manufactured in this way can store rainwater completely without allowing rainwater to penetrate into the ground in the first storage unit 12, and if rainwater is taken in by the pumping pump 30, rainwater can be effectively utilized. can do. On the other hand, in the 2nd storage part 13, as shown to the arrow A, the rain water which flows through the space | gap between the vitreous foams 40 will osmose | permeate into the ground gradually. At this time, since the vitreous foam 40 retains rainwater in the bubbles, the rainwater can permeate into the ground in a short period of time even if there is no sheet for shielding water around the second reservoir 13. Without rain, some rainwater can be stored. And if the rainwater which flows through the space | gap between the glassy foams 40 decreases, the rainwater which penetrate | infiltrated the bubble of the glassy foams 40 will osmose | permeate in the ground gradually.

  Further, since the glassy foam 40 has a large number of bubbles, water passes through the glassy foam 40 and the water is purified, and the purified water is stored in the first storage unit 12. Therefore, the water can be used sufficiently for watering plants and washing cars and gardens. Furthermore, since the vitreous foam 40 is alkaline, the water that has passed becomes alkaline with a pH of 9 or more. Therefore, it has an effect of preventing rainwater corrosion and an effect of suppressing recent growth of E. coli and the like. As a result of these effects, the rainwater storage tank 100 does not need to be maintained and can maintain its function for a long period of time.

  Furthermore, when discarding, since the vitreous foam 40 is a recycled product of glass, it can be disposed as soil as it is, and industrial waste is not generated.

Furthermore, it is not necessary to fix the surroundings of the storage unit 10 with concrete or the like, and most of the construction of the rainwater storage tank 100 can be performed only with heavy machinery, and since almost no manual work is required, the construction period can be shortened. As well as saving labor. Moreover, since it is not necessary to construct a foundation, the construction period can be further shortened.

Furthermore, when plants such as flower beds are planted on the upper surface of the rainwater storage tank 100, the water retained in the vitreous foam 40 of the second reservoir 13 appropriately moistens the embankment, so that water is sprayed. Time and effort can be reduced.

(Second Embodiment)
FIG. 3 is a front cross-sectional view showing an outline of the configuration of the rainwater storage tank 100 according to the second embodiment. The rainwater storage tank 100 of 2nd Embodiment is only the point which has arrange | positioned the water-permeable or the water-permeable sheet 23 on the side surface of the 2nd storage part 13 with respect to the rainwater storage tank 100 of 1st Embodiment. Different. Since other points are the same as those in the first embodiment, description thereof is omitted.

  As the water-permeable or water-permeable sheet 23, a plastic sheet, a nonwoven fabric or the like in which pores are formed is used. The water-permeable or water-permeable sheet 23 is disposed on the side surface of the second reservoir 13 to further adjust the speed at which rainwater that has permeated the second reservoir 13 penetrates into the ground, or the soil is in a glassy foam. This is to prevent penetration into the water. If the soil also advances into the glassy foam 40 by a certain amount, it has an effect of suppressing further permeation, but it becomes more effective by disposing the water-permeable or water-permeable sheet 23.

(Third embodiment)
FIG. 4 is a front cross-sectional view showing an outline of the configuration of the rainwater storage tank 100 according to the third embodiment. The rainwater storage tank 100 of the third embodiment is provided with a water-permeable or water-permeable cover sheet 25 on the upper surface of the second storage unit 13 with respect to the rainwater storage tank 100 of the second embodiment. Only the difference. The other points are the same as in the second embodiment, and thus the description thereof is omitted.

  As the cover sheet 25, a plastic sheet in which pores are formed, a nonwoven fabric, or the like is used. The cover sheet 25 is disposed on the upper surface of the second storage unit 13 to prevent the embankment soil from entering the vitreous foam. Basically, if a certain amount of soil penetrates into the vitreous foam 40 itself, the glass foam 40 has an effect of suppressing further permeation. Can be prevented.

(Fourth embodiment)
FIG. 5 is a front cross-sectional view showing an outline of the configuration of the rainwater storage tank 100 according to the fourth embodiment. The rainwater storage tank 100 of the fourth embodiment is formed so that the planar area of the second storage part 13 is larger than the planar area of the first storage part 12 with respect to the rainwater storage tank 100 of the first embodiment. The difference is that a water-permeable or water-permeable sheet 23 is disposed on the side surface of the second reservoir. The other points are the same as in the second embodiment, and thus the description thereof is omitted. By adopting such a configuration, it is possible to increase the amount of rainwater retained in the second reservoir 13 and to easily allow rainwater to penetrate into the ground from the lower surface of the second reservoir 13.

As Example 1, a 90 liter rainwater storage tank was produced by excavating a hole in a field and covering the periphery with a vinyl sheet. The rainwater storage tank of Example 1 contains 73.5% by weight of glass (waste glass component), 12.1% by weight of calcium oxide, 10.5% by weight of sodium oxide, and 1.57% by weight of aluminum oxide. Quality foam was embedded. As a comparative example, a 90 liter rainwater storage tank was made by drilling a similar hole in the field and covering the periphery with a vinyl sheet, and nothing was embedded inside. Rainwater collected in advance in both storage tanks is poured, and the upper surfaces of both Example 1 and Comparative Example 1 are covered with a waterproof sheet to make the comparison conditions the same. After 3 days, about 1 month, about 2 After months, rainwater was taken and the water quality was inspected. The test results are shown in Tables 1 and 2.

  Concerning turbidity, Comparative Example 1 detected water that was extremely turbid, especially after 3 months. On the other hand, in Example 1, almost no turbidity was visible. This is probably due to the purification action of the glassy foam.

About pH, the comparative example 1 showed pH of the grade which is a little over 8 from 8.12 to 8.64. On the other hand, Example 1 shows a pH value exceeding 9 at any time point after 3 days, about 1 month, and about 2 months, indicating that alkalinization is progressing.

As for the Langlia index, Comparative Example 1 had a low value of -0.96 after 3 days, but after 1 month and 2 months, it showed a value of 0.04 and was stable. On the other hand, Example 1 showed a high value from 0.79 to 1.02 after 3 days, 1 month, and 2 months. The Langeria index is a numerical value that serves as a measure of the corrosivity of water and the formation of a calcium carbonate film, and is calculated by the following formula 1. The larger the value, the easier the precipitation of calcium carbonate and the higher the non-corrosiveness. If it is about -1.0 or more from many examples, the non-corrosive effect can be expected.
(Equation 1)
Langeria index = pH-pHs
However, pHs = 8.313−log (Ca ²⁺ ) −log (A) + s
pH: Actual pH value of water
pHs: pH value when in equilibrium
log (Ca ²⁺ ): Logarithm of calcium ion concentration
log (A):
Logarithm of total alkalinity
s: Correction value

  From the above formulas, it can be seen that increasing the non-corrosive property (increasing the Langeria index) is achieved by either increasing the pH, increasing the alkalinity, or increasing the calcium ion concentration. In this experiment, the non-corrosive effect can be expected in both the examples and comparative examples, but the factors are different. The factor that increases the Langeria index in the examples is that the alkalinity is high. In the examples, the high alkalinity is mainly due to the vitreous foam, and as a result, strong non-corrosiveness is maintained. In general, the storage tank is charged with lime in order to keep the water alkaline, but this rainwater storage tank does not need this. On the other hand, the comparative example shows weak non-corrosiveness, which seems to be due to the large amount of calcium ions. Calcium ions appear to be supplied from the soil. From these comparisons, it is considered that calcium ions are precipitated in the examples, whereas in the comparative examples, they are released in an ionic state. For measuring the alkalinity, an acid having a pH of 4.3 was used, and the amount of acid consumed until neutralization to pH 7.0 was measured.

  Regarding the number of coliforms, in the comparative example, after 3 days, about 1 month, and about 2 months, the number of E. coli was gradually increased to 0, 55, and 78, respectively. In contrast, the examples were confirmed only at a very low level of 1 to 2 n / ml. The cause of the extremely small number of coliforms in the examples is considered to be alkalinization of water quality by vitreous foam. The inventors think that bacteria such as Escherichia coli tend to dislike the state of strong alkali and do not proliferate in the examples, given the condition that it is an experiment in a field.

  As shown in the embodiment described above, it can be used as a rainwater storage tank for storing rainwater.

DESCRIPTION OF SYMBOLS 10 ... Storage part, 11 ... Water intake part, 12 ... 1st storage part, 13 ... 2nd storage part, 20 ... Non-permeable plastic sheet, 23 ... Water permeability or water-permeable sheet, 25 ... Cover sheet, 30 ... Pump Apparatus, 31 ... Electric pump, 32 ... Water intake pipe, 33 ... Water intake, 40 ... Glassy foam, 100 ... Rainwater storage tank.

Claims (6)

A storage part for storing rainwater formed in the ground and a glass powder obtained by pulverizing a glassy waste material having a particle diameter of 1 mm to 200 mm embedded in a part or all of the inside of the storage part is heated and fired above the softening point. A glassy foam formed by cooling,
A water-impermeable first sheet member that covers a bottom surface and a lateral lower region of the reservoir, and
A rainwater storage tank, wherein the rainwater in the storage section can be alkalized to pH 9 or higher.   The rainwater storage tank according to claim 1, further comprising a water-permeable or water-permeable second sheet member that covers a laterally upper region of the storage unit.   The rainwater storage tank according to claim 1 or 2, wherein a third sheet member having water permeability or water permeability is laid on the upper surface of the embedded glassy foam.   The rainwater storage tank according to any one of claims 1 to 3, wherein an upper planar area of the reservoir is larger than a lower planar area.   The rainwater storage tank according to any one of claims 1 to 4, wherein the vitreous foam contains 5 to 25% by weight of calcium oxide with respect to the total weight.   The rainwater storage tank according to any one of claims 1 to 5, wherein the glassy foam has a water absorption rate of 30% or more.