JP3261463B2 - Soil purification method for sewage - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soil purification method for purifying sewage by passing sewage through soil.
It relates to the soil trench method.

[0002]

2. Description of the Related Art Organic matter-containing sewage from a sewage generation source is pretreated to separate solids, and then the sewage is separated from a sprinkling pipe such as a ceramic pipe and a crushed stone layer formed around the sprinkling pipe. The diffusion layer and the soil layer surrounding this diffusion layer, in order to infiltrate and diffuse into the soil, decompose the organic matter contained in the sewage by the action of microorganisms living in the soil, The soil trench method of returning water, carbon dioxide, and nitrogen to the natural world is known ("Water and wastewater" Vol. 29, No. 1, pp. 51-59 (1987)).

[0003] This sewage purification method has the advantages that organic matter and nutrients in sewage can be removed efficiently at the same time, and that capital investment and maintenance costs can be reduced. If the length is too long, clogging of organic matter is likely to occur near the boundary between the diffusion layer and the soil layer, and there is a problem that the purification function of sewage is reduced.

Accordingly, the present applicants have developed an infiltration layer or a diffusion layer (hereinafter referred to as an infiltration layer in the present invention) in which the above-mentioned diffusion layer is modified into a specific structure and the sewage infiltrates or diffuses widely into the soil layer. And the clogging state of the organic matter near the boundary is grasped by a change in the oxidation-reduction potential of the sewage, and when the oxidation-reduction potential falls below a predetermined value, air is fed into the vicinity of the boundary to cause an aerobic state. The present inventors have proposed an invention that activates the action of aerobic microorganisms living there (JP-A-7-214085).

[0005]

According to the present invention, clogging of organic matter near the boundary between the diffusion layer and the soil layer can be suppressed even if the soil trench method is performed for a considerably long time. It was later found that there were problems with the following points. (1) Since a device (trench device) for performing the soil trench method is underground, not only is it difficult to install a detection device for detecting the oxidation-reduction potential, but also the detection device exhibits its function. The frequency of detection (frequency of use about once every several tens of days) requires a detection device and a control device that activates an air blowing fan based on a signal from the detection device.

(2) Even if a detection device or the like can be installed, air is sent to the infiltration layer after detecting that the oxidation-reduction potential has dropped to a predetermined value, and the action of the aerobic microorganisms is performed by the air. It takes a considerable amount of time to actively decompose the organic matter that is causing clogging, and during that time, sewage flows near the boundary between the infiltration layer and the soil layer, and the purification function of the soil trench method decreases, As a result, there is a possibility that the water quality may be reduced. It is an object of the present invention to provide a sewage purification method capable of solving the above-mentioned problem and preventing clogging of organic matter near a boundary between the infiltration layer and the soil layer.

[0007]

In order to achieve the above-mentioned object, the present invention provides a water sprinkling means buried in the ground by intermittently supplying sewage by a pump so that the sprinkling water and the infiltration layer can be removed from the water sprinkling means. by sequentially moving the soil layer Te sewage soil remediation treatment smell for purifying wastewater, immersion by supplying air from the ground with respect to Junso, in the vicinity of the boundary between the invasion layer and the lower soil layer thereunder
Allow air to reach and maintain aerobic area near the boundary
Between the soil particles in the lower soil layer near the boundary
Prevent the occurrence of clogging and purify through the lower soil layer
Means for collecting the collected treated water (claim 1).
Invention).

[0008] may be to supply air from the ground against infiltration layer until the supply of the fouling <br/> water not only during the supply of sewage to the water spray means is restarted after interrupted once. The supply of air to the infiltration layer can be performed even when supplying sewage to the watering means. The supply of air to the infiltration layer can be performed continuously irrespective of the start / stop of the pump. Furthermore, it is preferable to supply more air than the volume to the infiltration layer to more reliably maintain the aerobic state near the boundary between the infiltration layer and the soil layer. Further, when the design specifications of the device in which the invention of claim 1 is implemented are clear, the amount A (l
/ M · times) of air is preferably supplied.

[0009]

A ≧ 22.4 (l / mol) × ｛(Q × C + R ×
S / N) / 32 (g / mol)｝ × 5 where Q is the amount of sewage supplied per meter of watering means (l / m · times), and C is the BOD concentration of sewage (g / l) ), S is the horizontal area of the soil layer occupied by 1 m of watering means (square m / m), R is the amount of oxygen (g / sq m / day) required for the microorganisms in the soil layer to inhabit, N Means the frequency (times / day) at which the supply of sewage to the watering means stops. Usually, the R is empirically 55 (g / g).
m · day).

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to FIGS.
The trench device in which the present invention is implemented is basically configured as follows. That is, as shown in FIG. 3, such as household toilets, public toilets installed in campsites, ski resorts, parks, and the like, solid substances such as sewage intermittently flowing from the sewage source side indicated by arrow X Tank 1 that rots the water, storage tank 2 that stores the supernatant liquid overflowing from the tank 1, and sewage pumped from the storage tank 2 by a submersible pump 3 is sprinkled on the trench soil layer 4. For preventing the treated water purified by the trench soil layer 4 from diffusing from a predetermined range, and collecting the treated water in the trench 6. A water collecting pipe 7 for water and draining in the direction of arrow Z is configured as a main element.

Each of the above elements will be described in more detail.
As shown in FIG. 1, the storage tank 2 is provided with two upper and lower cable float type upper and lower sensors 8 and 9.
When the upper sensor 8 detects a water level at a predetermined height, the pump rotates to continuously supply sewage to the sprinkling means 5, and when the lower sensor 9 detects a decrease in the water level, the rotation of the pump stops. As a result, the supply of sewage to the watering means 5 is interrupted. Therefore, the sewage is supplied intermittently from the storage tank 2 to the sprinkling means 5, that is, in a mode in which the cycle of supply and stoppage of the sewage is repeated, and the unit of the sewage from the sewage generation source side to the storage tank 2 is supplied. As the supply per hour increases, the downtime becomes shorter and the cycle becomes shorter.

The water sprinkling means 5 is composed of a water passing element such as a gutter or a pipe. The upper wall of the water sprinkling means 5 is provided with a water permeable element such as a perforated, slit or mesh so that the sewage can be sprinkled outward little by little while flowing down. A part is formed. The water collecting pipe 7 also has the above-described water-permeable portion on the pipe wall, and the treated water is collected from the trench soil layer 4 through the water-permeable portion.

The trench soil layer 4 has a structure in which four layers of a gravel layer 10, a lower soil layer 11 as a soil layer, an infiltration layer 12, and an upper soil layer 13 also as a soil layer are sequentially stacked. The water collecting pipe 7 is buried in the gravel layer 10 and the water sprinkling means 5 is buried on the infiltration layer 12 at the center. In this embodiment, the sprinkling means 5 is incorporated as a gutter in the sewage dispersion device 14 having a specific structure.

The gravel layer 10 is mainly made of gravel, so that the treated water that has passed through the lower soil layer 11 is easily collected in the water collecting pipe 7, and the direct contact between the soil of the lower soil layer 11 and the water collecting pipe 7 is cut off. Thus, clogging of the pipe wall of the water collecting pipe 7 is prevented. The lower soil layer 11 and the upper soil layer 13 are made of a soil having a relatively high porosity, for example, a clay porosity in which clay, silt and sand are mixed, and have a high porosity. I have. Microorganisms decompose organic matter in sewage that has infiltrated and diffused while breathing in these soil layers.

The infiltration layer 12 comprises a layer of high water permeable material in which a porous or granular porous material of porous calcium silicate, especially tobermorite, is spread to a predetermined thickness.
It has the function of infiltrating or diffusing sewage from the sewage diffusion device 14 and moving it to the lower soil layer 11, and also has the function of carrying microorganisms in sewage.

The sewage diffusion device 14 is installed in parallel with a water spray gutter 5 as a water spray means, a plate-like substrate 15 for supporting the water spray gutter 5, and a predetermined distance from the water spray gutter 5 at both edges of the substrate 15. And two ventilation ducts 16. A non-ceiling diffusion chamber 1 filled with a sewage purifying material S made of a granular or massive porous material of porous calcium silicate hydrate is provided between the spraying gutter 5 and the ventilation duct 16.
7 are formed. The sewage purifying material S is covered with a sheet-like permeable material 20, which allows the passage of water between the diffusion chamber 17 and the upper soil layer 13 and prevents the passage of soil particles.

A slit, a notch or a through hole is provided in the lower bottom portion of the ventilation duct 16 which is a part of the plate-like substrate 15 so that sewage from the diffusion chamber 17 flows into the infiltration layer 12. At the upper bottom, as shown in FIG. 2, a plurality of air supply pipes 18 are provided upright at predetermined intervals, and ground air is supplied to a ventilation duct 16 from a fan 19 attached to a tip end thereof. It is forcibly sent.

In the trench device having the above structure, the present invention is implemented as follows. First, when the trench apparatus is completed, the amount of wastewater for intermittently sending wastewater from the storage tank 2 to the sprinkler gutter 5 is determined. This dosage is measured as follows. At a certain point in time, when the pump 3 which has been stopped is rotated to supply sewage to the sprinkling gutter 5 of the sewage diffusion device 14 continuously for a short time, the sewage gradually leaks outward from the middle of the sprinkling gutter 5. While exiting and entering the two diffusion chambers 17, it eventually flows down to the tip of the watering gutter 5. Most of the sewage that has entered the diffusion chamber 17 passes through the gap of the sewage purification material S and then enters the ventilation duct 16, from which the infiltration layer 12
The sewage is partially diffused and infiltrated into
Is sucked up by the upper soil layer 13 by capillary action.

In this state, the sewage is discharged to the sewage diffusion device 1.
When sewage is flowed into the sprinkler gutter 5 at a flow rate equal to or higher than the flow rate of the sewage flowing into the infiltration layer 12 and the upper soil layer 13 through the sewage 4, the sewage is temporarily filled in the sewage diffusion device 14. After confirming that the sewage has filled the sewage diffuser 14, the pump 3
Stop. In this way, the amount of sewage fed to the sprinkler gutter 5 within a short period of time from when the pump 3 is rotated to when it is stopped, but during a continuous period of time is defined as the batch amount of the present invention.

It is to be noted that, as the use of the trench apparatus progresses, it becomes difficult for the sewage to escape from the middle of the sprinkler gutter 5 to the outside. Therefore, the batch amount is measured only once when the trench apparatus is operated for the first time or after maintenance is completed. Is enough. Whether or not the sewage has reached the tip of the sprinkler gutter 5 is determined by providing a sampling container at the tip of the sprinkler gutter 5 and observing whether or not sewage has entered the container.

Next, when the batch amount is determined, the upper and lower sensors 8, 9 are operated so that the pump 3 pumps up the batch amount of wastewater in the storage tank 2 by the operation of the lower sensor 9 and stops the pump by the operation of the upper sensor. Determine the water level sensing position. Then, the trench device is operated. Sewage intermittently flows into the septic tank 1 from the sewage source side, where solids are separated. The water level in the septic tank 1 rises, and the sewage flows into the storage tank 2. When the water level in the storage tank 2 reaches the installation level of the upper sensor 8, the pump 3 rotates and starts supplying sewage to the sprinkler gutter 5. At this time, the fan 19 may be rotated in accordance with the rotation of the pump 3 or before and after.

Since the pump 3 supplies the batch amount of sewage to the sprinkler gutter 5 at a stretch, the sewage reaches the tip of the sprinkler gutter 5 and leaks from the side wall thereof to enter the diffusion chamber 17. The sewage that has entered the diffusion chamber 17 eventually enters the infiltration layer 12 and the upper soil layer 13 as described above. Since the infiltration layer 12 is excellent in water permeability, most of the sewage entering the infiltration layer 12 is diffused to the lower soil layer 11, and a part of the sewage is sucked up by the upper soil layer 13. Microorganisms that live in both soil layers decompose organic matter in the sewage and purify the sewage. Infiltration layer 12
In this case, sewage is somewhat purified because microorganisms inhabit. The purified treated water is eventually collected by the collection pipe 7 of the gravel layer 10.

Next, the water level of the sewage in the storage tank 2 drops, the pump 3 stops, the flow of the sewage to the sprinkler gutter 5 is interrupted, and the sewage leaks from the sprinkler gutter 5 and flows into the infiltration layer 12. Disappears. Normally, in the sewage purification method, when sewage does not exist, air is not blown into the purification treatment system. However, in the present invention, the supply of sewage to the sprinkler gutter 5 is suspended until it is restarted. Then, air is blown into the infiltration layer 12 from the ground.

In this case, the air blowing amount A (l / m ·
Times) is 1m of watering gutter until the pump 3 rotates and stops.
Amount of wastewater supplied per unit (l / m-times), BO of wastewater
D concentration C (g / l), horizontal area S (square m / m) of trench soil layer 4 occupied by watering gutter 5 per meter, amount of oxygen required for microorganisms in trench soil layer 4 to inhabit R (g / square m-day), the number of times the pump 3 stops per day N (times / day), etc., but when these variables are clear as design specifications of the trench device,
It is preferable to operate the fan 19 so that the blowing amount A of the air) satisfies at least the above mathematical formula 1. In addition,
The above R is empirically set to 55 (g / square m · day).

If the above variables are not clear as the design specifications of the trench device, in the present invention, it is necessary to blow at least air corresponding to the gap of the infiltration layer 12 into the infiltration layer 12. Actually, the porosity of the infiltration layer 12 varies depending on the type of the highly permeable material and the compaction during the construction of the trench device, and it is difficult to measure an accurate amount. The above may be blown. By the way, there is no adverse effect due to too much blowing amount, and excess air is blown into the lower soil layer 11 and the upper soil layer 13 through gaps such as watering means.

When air is sent into the infiltration layer 12 as described above, the air flows in the vicinity Y of the boundary between the infiltration layer 12 and the lower soil layer 11.
To reach. In the vicinity Y of the boundary, the soil particles on the lower soil layer 11 side are relatively fine, so that sewage stagnates in the gap and organic matter is liable to be clogged. Becomes an aerobic state that is easy to be activated, and promotes the decomposition of organic matter that has been present or will enter later, thereby preventing the occurrence of clogging between soil particles near the boundary Y in advance. You.

In the above description, the start and stop of the fan 19 are performed in conjunction with the start and stop of the pump 3. However, the infiltration is performed at least until the supply of the sewage to the sprinkler gutter 5 is interrupted and restarted. As long as the condition that the air is supplied from the ground to the layer 12 to maintain the aerobic state in the vicinity of the boundary Y is satisfied, the supply of the air by the fan 19 is performed when the sprinkling gutter 5 is supplying sewage. The supply of air can be temporarily stopped when the time from when the supply of sewage is once stopped to when it is restarted is significantly longer than the sewage supply time.

Further, it is also possible to adopt a mode in which air is continuously sent to the vicinity Y of the boundary without stopping the fan 19 irrespective of the start / stop of the pump 3. In this aspect, there is an advantage that a control means for interlocking with the start / stop of the pump 3 becomes unnecessary. Next, the effects of the present invention will be described with reference to examples and comparative examples.

[0029]

【Example】

Example 1, Comparative Example 1 As shown in FIG.
m gravel layer 10, 68 mm thick lower soil layers 11, 15
An experimental device was fabricated assuming a trench device having a microbial-containing trench soil layer 4 having a length of 250 mm and a width of 100 mm, which comprises an infiltration layer 12 of mm and an upper soil layer 13 of 100 mm. Then, on the infiltration layer 12, the upper soil layer 13
40mm in height and 120m in length corresponding to a sewage diffusion device
m, a sewage storage tank 2 at one end, and an air supply pipe 1 for supplying air to the other end.
8 were connected respectively. Diffusion plates 21 for distributing the flow of sewage were provided at two locations in the water passage device 14, and the gravel layer 10 was provided with a water collecting pipe 7 for discharging treated water.

Using the experimental apparatus having such a structure, a soil purification experiment on sewage was conducted as follows. First, a sensor for measuring the oxidation-reduction potential was embedded in the trench soil layer 4 everywhere, and then 1 liter of sewage was poured into the storage tank 2 in eight times, once every three hours. As test sludge, BOD concentration is 600mg / l, S
Human waste having an S concentration of about 250 mg / l was used. And
The time (permeation time) required until the drainage of the treated water from the water collection pipe 7 through the trench soil layer 4 was started was measured (permeation time), and the air supply pipe 18 was passed through the water passage device 14 at a rate of 100 ml / min (for the infiltration layer 12). (An amount corresponding to about 35 times).

In this way, the soil purification experiment of sewage was continued for about half a year, and it was understood how the permeation time changes as the experiment elapses, and the oxidation-reduction potential in the trench soil layer 4 was measured. . As a result, as shown in FIG. 5, the permeation time was within 20 minutes even though 180 days had passed. The oxidation-reduction potential of the infiltration layer and the upper and lower soil layers 13 and 11 was 230 mV or more at any point. Also, when the amount of organic matter deposited in the trench soil layer 4 was measured at 2 months, 4 months and 6 months after the start of the experiment, 0.37 g, 1.89 g and 3.15 g in 100 ml of soil were obtained. (Example 1).

For comparison, the water supply device 1
An experiment was conducted in the same manner as in Example 1 without blowing air into Sample No. 4, and the permeation time and the oxidation-reduction potential were measured. As a result, as shown in FIG. 5, the infiltration time was rapidly increased after 120 days, and it was not possible to treat the designed amount of sewage in one day after 150 days. By the time 180 days had passed, it had reached 700 minutes. The redox potential is -300 mV in the infiltration layer 12 and the lower soil layer 11
Had fallen. In the same manner as in Example 1, two months, four months, and six months after the start of the experiment, the amount of organic matter deposited in the trench soil layer 4 was measured. .60 g, 8.08 g and 9.1
3 g, which was about 3 times or more that of Example 1 (Comparative Example 1).

As is clear from Example 1 and Comparative Example 1, the supply of sewage to the water passage device 14 corresponding to the water sprinkling means is interrupted by air before the water is restarted. According to the method of the present invention, the permeation time can be suppressed from being lengthened, and the reduction in the oxidation-reduction potential can be suppressed. That is, the clogging of the infiltration layer 12 and the lower soil layer 11 with the organic matter can be eliminated, and at least the vicinity of the boundary between the infiltration layer 12 and the lower soil layer 11 can be maintained in an aerobic state.

Example 2 and Comparative Example 2 As described above, the effects of the present invention were proved in a laboratory, and a demonstration experiment of the present invention was performed as follows. That is, as a sewage treatment facility for toilets in a truss manufacturing factory, a trench device shown in FIG. 3, that is, a septic tank 1, a storage tank 2, a trench soil layer 4
Was installed as a major component. Trench 6
Has a length of 12 m, a width of 2 m and a depth of 0.8 m, in which a 10 cm thick gravel layer 10, a 27 cm thick lower soil layer 11, and a porous calcium silicate hydrate granule A trench soil layer 4 consisting of a 3 cm infiltration layer 12 and a 40 cm thick upper soil layer 13 was formed.

Further, a length of 10 m is placed on the infiltration layer 12.
And the diffusion chamber 17 is filled with a sewage purifying material S made of tobermorite, having a width of 1 m and a depth of 0.08.
m of wastewater diffusion apparatus 14 was installed. Four fans 19 are provided on the ground to blow air into the infiltration layer 12 from the outside.
Is provided so that air can be blown from the air supply pipe 18 to the infiltration layer 12. In addition, the infiltration layer 12 and the upper and lower soil layers 13, 1
In order to monitor the clogging near the boundary with No. 1 with the oxidation-reduction potential, an oxidation-reduction potential detection sensor was buried everywhere in the trench soil layer 4.

When a sampling vessel was attached to the tip of the sprinkler gutter 5 and sewage was flowed at various flow rates and the amount of the sewage was measured, it was 0.25 cubic meters. Upper and lower sensors 8 and 9 are provided in the storage tank 2 so that the amount of sewage corresponding to this amount can be intermittently flown into the sprinkler gutter 5. Then, the trench apparatus was subjected to a verification test for use in a public toilet (nominal capacity 20-person tank).

In this demonstration test, the amount of wastewater generated was 1.18 cubic meters / day on average, and the number of times of pumping from the storage tank 2 to the sprinkler gutter 5 by the pump 3 was 5 times / day on average.
Sewage pH is 7.7, BOD concentration C is 94.8mg /
1 and SS concentration were 63.1 mg / l. During the experiment period, without stopping the fan 19, about 0.33 cubic m /
Minute, i.e., 130 liters (l) / m per sprinkler gutter
Minute air was sent to the infiltration layer 12. In this demonstration device, Q is 25 liters / m · times, and S is 2
Since the square m / m, R is 55 g / square m · day, and N is 5 times / day, the lower limit of the air blowing amount A represented by the formula 1 is 85 liters / m · times. Is larger than this value.

As a result of the verification test for about one year, the oxidation-reduction potential was 200 mV or more at any part of the trench soil layer 4, and there was no clogging near the boundary between the infiltration layer 12 and the upper and lower soil layers 13, 11. The operation of the trench equipment was completed. The pH of the treated water was 7.0, the BOD concentration C was 3.4 mg / l (removal rate 98.5%), and the SS concentration was
At 4.2 mg / l (98.9%), the wastewater standard was greatly cleared (Example 2).

After the end of the second embodiment, if the supply of air to the infiltration layer 12 is stopped between the time when the supply of the sewage to the sprinkler gutter 5 is once stopped and the time when the supply is restarted, the oxidation reduction of the trench soil layer 4 is performed. An experiment was conducted on how the potential changes (Comparative Example 2).

In Comparative Example 2, as shown in FIG. 7, air was blown into the infiltration layer 12 until 20 days had elapsed since the start of the experiment, and then 10 days later (30 days after the start of the experiment). Air blowing was stopped until the day when the day reached). As a result, the infiltration layer 12 and the upper and lower soil layers 1
The oxidation-reduction potential near the boundary between 3 and 11 was lowered from 200 mV to -150 mV, and there was a possibility that clogging might occur. Therefore, air blowing was started again. As a result, about 30 days after that date, the oxidation-reduction potential was recovered as before.

As is evident from Example 2 and Comparative Example 2, air was supplied to the infiltration layer 12 between the time when the supply of sewage to the sprinkler gutter 5 was once interrupted and the time when it was restarted. If the vicinity of the boundary between the soil and the soil layer is maintained in an aerobic state, clogging of organic matter near the boundary can be eliminated.

Note that the present invention is not limited to the configuration of the above-described embodiment, but can be embodied by appropriately changing the scope of the invention as follows, for example, as follows. (1) The frequency of use of the public toilet changes according to the season and time, and the number of times the pump 3 starts and stops changes accordingly. When the number of times increases, the fan 19 can be operated continuously, and when the number of times decreases, the fan 19 can be started in synchronization with the pump 3. (2) The volume of air blown into the infiltration layer 12 is equal to or larger than the volume described above, but the upper limit is not limited. Considering the maintenance costs, the air is naturally blown to the minimum necessary amount. (3) The infiltration layer 12 may be a mode that partially covers the trench groove 6 without completely covering the trench groove 6 or a mode that surrounds the sprinkler tube. (4) The trench device may be an open type having no trench 6. In this embodiment, since the action of the upper and lower soil layers 11 and 13 usually extends about 50 cm outward from the infiltration layer 12, the above range is defined as the upper and lower soil layers of the present invention.

[0043]

As described above in detail, the method of the present invention relates to a soil purification method for purifying sewage by microorganisms in soil by infiltrating and diffusing sewage into a soil layer from a watering means through an infiltration layer. An excellent effect of preventing the clogging of organic matter, which tends to occur near the boundary between the soil and the soil layer, and maintaining the function of the soil purification method for a long period of time is exhibited.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of a typical trench apparatus to which the present invention is applied, partially cut away.

FIG. 2 is a diagram showing a cross section of the trench device.

FIG. 3 is a diagram showing a configuration of the trench device.

FIG. 4 is a perspective view showing the trench device used in the first embodiment, partially cut away;

FIG. 5 is a diagram showing the relationship between the elapsed days of the experiment and the permeation time in Example 1.

FIG. 6 is a diagram showing a variation state of an oxidation-reduction potential in Comparative Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotting tank 2 Storage tank 3 Pump 4 Trench soil layer 5 Watering means 7 Water collecting pipe 10 Gravel layer 11 Lower soil layer 12 Infiltration layer 13 Upper soil layer 16 Ventilation duct 18 Air supply pipe 19 Fan

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masao Nojiri 2035 Shimo-machi, Shioi-machi, Owariasahi-shi, Aichi Pref. Inside the Materials Research Laboratory, Noda ELC Co., Ltd. 4-8-4 Kawahito Taiyo Kogyo Co., Ltd. Civil Engineering Division (72) Inventor 4-8-4 Kikawahigashi, Yodogawa-ku, Osaka-shi, Osaka Taiyo Kogyo Co., Ltd. Civil Engineering Division (72) Invention Person Kana Shiraki 4-8-4 Kikawahigashi, Yodogawa-ku, Osaka-shi, Osaka Taiyo Kogyo Co., Ltd. Civil Engineering Division (56) References JP-A-57-204290 (JP, A) JP-A-50-42672 (JP) , A) Actually open 1983-48389 (JP, U) Actually open 1983-48390 (JP, U) Actually open 1984-150585 (JP, U) Flat 7-7797 (JP, U) (58 ) investigated the field (Int.Cl. ^7, DB name) C02F 3/00

Claims (6)

(57) [Claims] A pump (3) intermittently supplies sewage to a watering means (5) buried in the ground, and the watering means (5) supplies the infiltration layer (12) and the soil layer ( 11,
13) In the sewage soil purification method for purifying sewage by sequentially moving the sewage to the infiltration layer (12), air is supplied from the ground to the infiltration layer (12) and the lower soil layer ( 11) by allowing the air to reach the vicinity (Y) of the boundary and maintaining the vicinity of the boundary (Y) in an aerobic state,
Clogging between soil particles in the lower soil layer (11) near the boundary (Y) is prevented, and the lower soil layer (11)
A method for soil purification of sewage, comprising collecting treated water purified through a soil. 2. During the supply of sewage to said watering means (5).
Soil remediation treatment of wastewater according to claim 1, wherein supplying the air from the ground with respect to even the infiltration layer until the supply of the sewage not a Minara is resumed from the ceased temporarily (12). 3. The supply of air to the infiltration layer (12)
3. The soil purification method for sewage water according to claim 2, wherein the method is carried out even when sewage water is supplied to the water sprinkling means. 4. The supply of air to the infiltration layer (12)
3. The soil purification method for sewage water according to claim 2, wherein the method is performed continuously irrespective of the start / stop of the pump (3). 5. The method according to claim 2, wherein air is supplied to the infiltration layer in an amount larger than its volume. 6. An amount A (l / m ·) represented by the following formula per m of the watering means (5) with respect to the infiltration layer (12).
3) A method for soil purification treatment of sewage according to claim 2, wherein air is supplied: A ≧ 22.4 (l / mol) × {(Q × C + R × S / N) / 32 (g / mol)} × 5. In the above formula, Q is the amount of sewage supplied per meter of watering means (l / m.times.), C is the BOD concentration of sewage (g / l), and S is the level of the soil layer occupied per meter of watering means. Area (square m / m), R is the amount of oxygen (g / sq m / day) required for microorganisms in the soil layer to inhabit, N
Means the frequency (times / day) at which the supply of sewage to the watering means stops.