JP2000288563A - Waste water treatment method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste water treatment method and apparatus capable of satisfying the requirements that equipment cost and maintenance control cost are low and operation cost is not almost required, waste water is sufficiently purifying without almost generating soil pollution and nitrogen or phosphorus in waste water can be efficiently removed. SOLUTION: Waste water advances in the order of a waste water pipeline 21, a low speed flow pipeline 31 and an anaerobic tank. Waste water in both pipelines 21, 31 are treated with aerobic bacteria before waste water flows in the anaerobic tank 41. The primary treated water flowing in the anaerobic tank 41 from the low speed flow pipeline 31 is treated with anaerobic bacteria in the anaerobic tank 41. The secondary treated water overflowing from the anaerobic tank 41 is treated with aerobic bacteria in an anaerobic bed 11 and tertiary treated water is treated with anaerobic bacteria in an anaerobic bed 12 under the aerobic bed 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wastewater treatment method and a wastewater treatment device which are effective for preventing water pollution (improving water quality) and preventing soil pollution.

[0002]

2. Description of the Related Art Various types of wastewater discharged from homes and the like are appropriately purified in each region and then discharged to public waters such as rivers. However, the means of treating wastewater differ greatly between cities with high population density and municipalities with low population density. For example, in a city where sewerage is widespread, wastewater is treated through a series of sewerage facilities consisting of sewer pipes, pumps, and wastewater treatment plants.In areas without sewerage facilities, wastewater is drained using single septic tanks or combined septic tanks. Must be processed. In some areas, untreated wastewater is discharged into nearby waterways. By the way, the penetration rate of sewerage reaches 90% only in cities with a population of 1 million or more, and in municipalities with a population of 10,000 or less, the penetration rate is only about 10%.
This means that the reliance on septic tanks is still quite high.

The above-mentioned wastewater treatment means will be briefly described. A sewage treatment plant (final treatment plant) is for treating a large amount of sewage, a combined clarification tank is for treating human waste and household wastewater, and a single clarification tank. Means to treat only human waste. Regardless of the size of the equipment, these means often perform wastewater treatment using microorganisms such as aerobic bacteria and anaerobic bacteria.

[0004] Among the wastewater treatment means, in the case of sewage, a huge amount of equipment cost is required, and the completion period is as long as 30 to 60 years. Therefore, as a provisional measure until that time, a combined septic tank or a single septic tank is used. I do. However, the cost of setting up a septic tank is about 500,000 yen for a single septic tank (for 5 persons), and the co-payment for the combined septic tank (for 5 persons) after subsidizing is almost the same as that for a single septic tank. I can't say. If operating costs and maintenance costs are added to this, the cost of the septic tank will increase further.

[0005] As an average case, one person takes 2
If 00 liters of water is used, 40 g of dirt will come out. The 40 g of soil is 13 g for human waste and 27 g for miscellaneous drainage. On the other hand, the discharge standard based on the BOD value is 90 ppm for a single septic tank and 20 p for a combined septic tank.
pm. From this point of view, in a single septic tank that processes only human waste, 8 g out of 13 g of human soil dirt
Only 5 g of remaining dirt and dirt of gray water 2
A total of 32g, including 7g, will be released to the river. The combined septic tank, on the other hand, reduced 40 g of dirt to about 90
% Removal to 4 g, surpassing a single septic tank in terms of treatment effect.

[0006] Human excrement contains a large amount of nitrogen and phosphorus, and household wastewater also contains these. Therefore, the wastewater treated in the septic tank also contains nitrogen and phosphorus. It has long been pointed out that nitrogen and phosphorus, when they flow into rivers and seas, cause excessive eutrophication of river water and seawater, causing various adverse effects. Nitrogen is nitrified by nitrifying bacteria and then denitrifying bacteria (facultative anaerobic bacteria) are degraded by depriving oxygen when nitric nitrogen and nitrite nitrogen are effective. That is, the nitrogen gas is decomposed in the order of nitrate nitrogen → nitrogen gas → water → hydroxide ions and the nitrogen gas is released into the air. In addition, the treated water that has become acidic due to nitrification is also neutralized with alkaline hydroxide ions. However, in the case of ammonia nitrogen, denitrifying bacteria do not work effectively because they do not contain oxygen. This is the BOD reference value =
When applied to a combined septic tank of 20 ppm, in the case of the combined septic tank, although the transparency of the treated water is relatively high, the nitrogen contained in the water is not completely converted into nitric acid. , Treated water flows into rivers. And when it comes to water purification plants that take water from such rivers, the amount of trihalomethane (carcinogen) contained in clean water is reduced because a large amount of chlorine is injected at the time of chlorination, based on the ammonia nitrogen content. To increase. B
This is the case with a combined septic tank with an OD reference value of 20 ppm, so that a single septic tank with a BOD reference value of 90 ppm is even more so.

[0007]

As will be apparent from the above description, complete and complete sewerage requires a huge expenditure and a long period of time, and a single septic tank and a combined septic tank require initial costs and running costs. This imposes a heavy burden. This situation is also expected to impair the promotion of purification facilities in areas without sewerage facilities, which may cause the discharge of untreated wastewater and the dumping of sewage, further deteriorating water quality. In addition, septic tanks must be improved over existing ones in order to efficiently remove nitrogen and phosphorus.

SUMMARY OF THE INVENTION In view of the above technical problems, the present invention has a low facility cost and a low maintenance cost, requires almost no operating cost, has a sufficient purification of drainage, and shows almost no soil pollution. Further, an object of the present invention is to provide a wastewater treatment method and a wastewater treatment apparatus that can satisfy nitrogen and phosphorus in wastewater, for example, by efficiently removing them.

[0009]

The wastewater treatment method according to claim 1 of the present invention is characterized by the following means for achieving the intended object. That is, the wastewater treatment method according to the first aspect of the present invention is characterized in that the wastewater that proceeds in the order of the drainage pipe, the low-speed flow pipe, and the anaerobic tank buried in the aerobic stratum flows into the anaerobic tank until the wastewater proceeds. During the primary treatment step of treating the wastewater in the flow pipe with aerobic bacteria, and while the primary treated water flowing into the anaerobic tank from the low-speed flow pipe is stagnant in the anaerobic tank, the primary treated water is placed in the anaerobic tank. When the water level in the anaerobic tank rises due to the secondary treatment step of treating with the anaerobic bacterium and the incoming water flowing in later, the secondary treated water overflowing from the anaerobic tank permeates the aerobic stratum,
A tertiary treatment step of treating the infiltrated secondary treated water with aerobic bacteria in the aerobic stratum, and, when the tertiary treated water penetrates to the anaerobic stratum below the aerobic stratum, anaerobically treats the permeated tertiary treated water. And a quaternary treatment step of treating with an anaerobic bacterium in a soil layer.

[0010] The wastewater treatment apparatus according to claim 2 of the present invention is characterized by the following means for solving the problem in order to achieve the intended object. That is, the wastewater treatment apparatus according to claim 2 includes a drainage pipe for introducing wastewater, a vertical low-speed flow pipe having a water inlet at a lower part, and a vertical anaerobic tank having an open upper surface. And that the tip of the drainage pipe is connected to the low-speed flow pipe and they are in communication with each other, and that the vertical low-speed flow pipe is disposed in the vertical anaerobic tank and The pipe line and the anaerobic tank communicate with each other via a water inlet.

[0011] The wastewater treatment apparatus according to claim 3 of the present invention comprises:
In the structure described in claim 2, each of the plurality of pipes is:
A part of the peripheral surface is formed by a grooved member that is opened and a closing member that removably covers the open peripheral surface of the grooved member, and a connection port is formed in one of these closing members. And that a plurality of pipes are vertically connected to form a low-speed flow pipe, and that the drain pipe is connected to the low-speed flow pipe via a connection port. Features.

[0012] The wastewater treatment apparatus according to claim 4 of the present invention comprises:
3. The apparatus according to claim 2, wherein a plurality of pipes are vertically connected to each other to form a low-speed flow pipe, and a connection port is formed in one of the short pipes. , And the drainage line is connected to the low-speed flow line via the connection port.

[0013] The wastewater treatment apparatus according to claim 5 of the present invention is characterized by the following means for solving the problems in order to achieve the intended object. In other words, the wastewater treatment apparatus according to claim 5 is a drainage pipe for drainage introduction, a horizontal low-speed flow pipe having a water inlet on the lower surface and both ends closed, and a horizontal low-pressure flow pipe with an open upper surface. An anaerobic tank, and that the end of the drainage line is connected to the low-speed flow line so that they communicate with each other. The low-speed flow pipe and the anaerobic tank are disposed in an anaerobic tank, and communicate with each other via a water inlet.

Action: The wastewater treatment in the wastewater treatment method and wastewater treatment apparatus of the present invention is as follows. The drain line is connected to the low-speed flow line. The low-speed flow pipe communicates with the anaerobic tank via a lower water inlet. The anaerobic tank is buried in the aerobic stratum, and its open upper surface communicates with the aerobic stratum. Further below the aerobic formation is an anaerobic formation. Therefore, the order of drainage flow is as follows: drainage line → low-speed flow line → anaerobic tank → aerobic stratum → anaerobic stratum.
The following first to fourth step processing will be performed.

[0015] The primary treatment step is performed in the pipeline until the wastewater flows into the anaerobic tank, that is, in the drainage pipeline or the low-speed flow pipeline. The wastewater before treatment flowing from the drainage pipe to the low-speed flow pipe has a large amount of dissolved oxygen and flows while entraining air, so that aerobic bacteria are dominant in these pipes. Therefore, various organic substances contained in the wastewater are decomposed by the aerobic bacteria to lower the BOD value. Incidentally, ammonia becomes nitrite nitrogen by nitrite, and nitrite becomes nitrate nitrogen by nitrate. The wastewater after the treatment, that is, the primary treated water, gradually enters the next anaerobic tank due to the small diameter of the water inlet at the lower part of the low-speed flow pipe, and Stop the approach when the water level and the water level in the anaerobic tank become the same level.

The low-speed flow pipe and the anaerobic tank communicate with each other through a water inlet at the lower part of the low-speed flow pipe. Do not flow into. Therefore, the inside of the anaerobic tank is maintained in a well-conditioned anaerobic atmosphere, and anaerobic bacteria grow in the tank. In addition, since the flow of the wastewater in the intermittent flow is discontinuous, the wastewater in the low-speed flow pipe or the anaerobic tank stagnates until the next wastewater flows. The secondary treatment step for the primary treatment water is performed in an anaerobic tank under such circumstances. That is, since the BOD value of the primary treated water is lower than that of the wastewater at the beginning, the anaerobic bacteria work well in the anaerobic tank, and the denitrifying bacteria consume the residual oxygen in the anaerobic tank and remove residual contaminants (nutrition). Work while feeding. Therefore, in the case of the secondary treatment step, nitrogen is well removed, if not all. In addition, when zeolite, activated carbon, shells (oyster shells), iron scraps (rusted iron), etc. are put in the anaerobic tank as a filter medium, the effect of removing various contaminants is further enhanced. For example, shells and iron shavings are effective in removing phosphorus. Since zeolite has a remarkable ion exchange action and has a molecular sieving action, it has a high contaminant adsorption effect. Activated carbon not only has a high effect of adsorbing pollutants, but also has an effect of removing trihalomethane.

The subsequent drainage also flows into the low-speed flow pipe through the drain pipe in the same manner as described above, and accordingly, the water level in the low-speed flow pipe and the anaerobic tank increases. The secondary treatment water gradually raises the water level by repeating this, and eventually overflows from the anaerobic tank and permeates the aerobic stratum. The tertiary treatment step for the secondary treatment water is performed in such aerobic stratum. Generally, the stratum up to about 5 to 6 m below the ground shows aerobic, and here a variety of aerobic bacteria inhabit. Therefore, the overflowed secondary treated water is decomposed again by the aerobic bacteria in the stratum, and the organic matter remaining therein is decomposed by the BOD.
Decrease the value further. As is self-evident, the aerobic formation (natural formation) is very large and has abundant aerobic bacteria species and abundant bacterial content, so that it has a high treatment capacity and odor components are decomposed by the microorganisms used therefor. In addition, when trees and grass are planted on the surface side of the aerobic stratum, the plants absorb nitrogen and phosphorus as nutrients, so the cleanliness of the treated water in the tertiary treatment step, that is, the tertiary treated water, is further enhanced. .

The tertiary treated water permeates into the underground as time passes, and reaches the anaerobic formation from the aerobic formation. The anaerobic formation below the aerobic formation is one in which anaerobicity increases as the depth of the ground increases, and it is inhabited by a wide variety of anaerobic bacteria. The anaerobic stratum, which is a natural stratum, also has a high processing capacity because of its vastness and richness in the species and amount of anaerobic bacteria. In addition, denitrifying bacteria work well for nitrified low BOD wastewater. Therefore, the tertiary treated water having a low BOD value that has penetrated into the anaerobic stratum is often subjected to denitrification treatment in this stratum, resulting in tertiary treated water having a high degree of denitrification.

The wastewater treated up to the fourth order is B
OD value is low, especially nitrogen is well removed. Therefore, even if the treated water is recharged as groundwater or seeps into rivers, it is unlikely that the treated water will be polluted. Of course, soils such as aerobic and anaerobic formations are also free from pollution due to the diverse and abundant underground microorganisms. On the other hand, when treating wastewater by such means, it is only necessary to bury a simple tank in the shallow ground (aerobic stratum) or to simply pipe it, so that equipment costs do not increase and operating costs are not required. In addition, there is almost no cost for maintenance. And the installation space is small.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a wastewater treatment method and a wastewater treatment apparatus according to the present invention will be described with reference to the accompanying drawings.

In the embodiment of FIG. 1, 11 is an aerobic formation, 12 is an anaerobic formation, 21 is a drainage line for introducing drainage,
Reference numeral 31 denotes a low-speed flow pipe, 41 denotes an anaerobic tank, and 51 denotes a filter medium.

The aerobic stratum 11 in FIG. 1 is often a stratum up to about 5 to 6 m below the ground, where a variety of aerobic bacteria inhabit. If necessary, activated sludge for wastewater treatment may be embedded in the aerobic formation 11, where useful aerobic bacteria may be propagated. In FIG. 1, an anaerobic stratum 12 below an aerobic stratum 11 is often a stratum below about 6 to 7 m underground, where a variety of anaerobic bacteria inhabit. In this anaerobic formation 12, useful anaerobic bacteria may be artificially propagated.

The drain pipe 21 shown in FIG. 1 is formed of a known pipe such as a synthetic resin pipe, a metal pipe, a fume pipe, and a concrete pipe. The drain pipe 21 may be equipped with one or more well-known open / close cocks (valves).

The vertical low-speed flow line 31 illustrated in FIG.
Is composed of a vertically long groove-shaped member 32, a plurality of closing members 35, and a lid 37. The channel member 32 has an arc shape like a C-shape when viewed from a plane. Referring to FIG. 2, holding grooves 33 a for fitting and holding a plurality of closing members 35 are formed at both end edges of the groove-shaped member 32 along the longitudinal direction. At the lower end of the channel-shaped member 32, a plurality of water passages 34 formed by notching a plurality of spots
There is. This type of water inlet 34 may be a hole formed in the lower peripheral wall of the channel member 32. By appropriately setting the size and number of the water inlets 34, the amount of treated water discharged per unit time from the low-speed flow conduit 31 can be made appropriate. The plurality of closing members 35 also have an arc shape. One of the closing members 35 has a connection port 36 for piping. When a predetermined number of the closing members 35 are fitted into the holding grooves 33a of the groove members 32, the groove members 32 and the respective closing members 35 form a tube as shown in FIG. The lid 37 is for opening and closing the upper surface of the tubular body composed of the channel member 32 and the closing member 35. In addition, a plurality of fixing tools 38 distributed in the circumferential direction are attached to the outer peripheral surface of the lower end of the tube constituted by the groove member 32 and the closing member 35 by a known means. Each constituent member of the low-speed flow conduit 31 is also made of synthetic resin (including FRP), metal, ceramics (including materials of pottery pipes and clay pipes), concrete, etc., except for the fixture 38.
The fixture 38 is often made of synthetic resin or metal.

The anaerobic tank 41 has an open-top tank structure. Anaerobic tank 41 is also made of synthetic resin (including FRP), metal,
It is made of ceramic (including pottery and clay pipe materials) and concrete. The filter medium 42 put in the anaerobic tank 41
Sand (example: mountain sand), pebble, crushed stone, crushed ceramic (example: crushed unfired brick or unfired tile), activated carbon, coal, charcoal, zeolite, silica, shell (eg, oyster shell), iron scrap (example) : Rusted iron), vegetable fibers, synthetic fibers, wood chips (wood chips), catechin-containing materials, etc. Regarding the filter medium 42, one or more of these examples are selected and filled in the anaerobic tank 41.

The configuration of the wastewater treatment apparatus using the above-described components is as follows with reference to FIG. The aerobic stratum 11 is dug to bury the anaerobic tank 41.
The digging depth for the aerobic stratum 11 is set within a range of 1 m to 5 m, and the depth is usually about 1 m to 3 m. In this connection, grooves for pipes and the like are also dug in the aerobic formation 11. The anaerobic tank 41 is installed in a dug hole of the aerobic stratum 11. After the low-speed flow pipe 31 is installed at the center of the anaerobic tank 41,
Fixed to 1. In this case, a part of the low-speed flow pipe 31 is constituted by a plurality of closing members 35, and one of the closing members 35 has a connection port 36. Therefore, the closing member 35 having the connection port 36 is connected to the drain pipe 21 described later.
Is set at a predetermined height in the low-speed flow pipe 31 so as to correspond to the pipe level of the low-speed flow pipe 31. After the low-speed flow pipe 31 is provided, the above-described filter medium 42 is provided in the anaerobic tank 41.
Is filled. The drainage pipe 21 extends from a drainage generation part (or drainage storage part) on the ground to a low-speed flow pipe 31. More specifically, one end of the drainage pipe 21 is connected to a pipe on the side of the drainage generation unit (or the drainage reservoir), and the other end of the drainage pipe 21 is connected to the inside of the low-speed flow pipe 31 through the connection port 36. Be drawn in. After the completion of the installation in the soil in this way, the drainage line 21, the low-speed flow line 31, the anaerobic tank 41, and the like are covered with soil, and the low-speed flow line 3 having the cover 37
Only the upper end of 1 is exposed on the ground surface side.

The wastewater treatment method using the wastewater treatment apparatus shown in FIG. 1 is carried out as follows in a process where wastewater flows naturally.

When water is used on the ground, drainage occurs with each use. The drainage generated intermittently flows through the drainage line 21 directly or via the drainage reservoir, and reaches the low-speed flow line 31. The drainage in the low-speed flow pipe 31 flows into the anaerobic tank 41 from the water passage 34 at the lower part thereof. When the amount of wastewater starts to exceed the capacity of the anaerobic tank 41, the wastewater overflows from there and permeates into the aerobic formation 11 and the anaerobic formation 12. Regarding the rise in which microorganisms start to work actively, in this series of systems, that of the anaerobic tank 41 is relatively slow. Nevertheless, the anaerobic bacteria in the anaerobic tank 41 start working effectively several months after the installation of the apparatus. Therefore, drainage line 21 → slow flow line 31 → anaerobic tank 41 →
In the process of drainage flowing from the aerobic stratum 11 to the anaerobic stratum 12, the above-described first to fourth step processes are performed. Based on the above description, these processing steps
It is as follows.

Primary treatment step: The waste water before treatment flowing from the drain pipe 21 to the low-speed flow pipe 31 has a large amount of dissolved oxygen and flows while entraining air. Reduces the BOD value by decomposing various organic substances contained therein with aerobic bacteria. This primary treated water slowly enters the anaerobic tank 41 from the lower part of the low-speed flow pipe 31 because the diameter of the water inlet 34 is small,
When the water level in the low-speed flow pipe 31 and the water level in the anaerobic tank 41 become the same level, the approach is stopped.

Secondary treatment step: The inside of the anaerobic tank 41 has a water passage 3
No air flows in because block 4 is blocked by drainage, and drainage stagnates until the next drainage flows in. Under such circumstances, the primary treated water that has flowed into the anaerobic tank 41 undergoes a secondary treatment with the anaerobic bacteria in the tank. And anaerobic tank 41
When the inside is filled with the filter medium 42, various contaminants in the primary treatment water are removed thereby.

Tertiary treatment step: The secondary treatment water in the anaerobic tank 41 permeates the aerobic stratum 11 when overflowing from there. In the aerobic stratum 11, various aerobic bacteria living here perform tertiary treatment in which the secondary treated water is decomposed again and its BOD value is further reduced.

Fourth treatment step: The third treatment water permeates into the anaerobic formation 12 below the aerobic formation 11. Therefore, the tertiary treated water having a low BOD value that has reached the anaerobic stratum 12 is often denitrified in this stratum and becomes tertiary treated water with a high denitrification degree.

In the embodiment of FIG. 1, the low-speed flow conduit 31 illustrated in FIGS. 3 and 4 can be used in place of the low-speed flow conduit 31 of the illustrated example. The low-speed flow pipe 31 shown in FIGS. 3 and 4 is configured by connecting a plurality of short pipes 39 in upper and lower stages, and each of the middle short pipes 39 and the lower short pipe 3
As shown in FIG. 4, a holding groove 33b for fitting and holding the lower end of each upper short pipe is formed at the upper end of each of the lower pipes 9 in FIG. Of the short pipes 39, the connection port 36 is formed in one of the short pipes 39 or the short pipe 3 in the lowermost stage.
9 is similar to the above in that a water outlet 34 is formed at the lower end. In the case of this example as well, when assembling the low-speed flow pipe 31, the short pipe 39 having the connection 36 is positioned at a predetermined height so that the connection 36 is connected to the drain pipe 21.
Pipe level. 3 and 4 are the same as or similar to the previous example.

FIGS. 5A to 5F show various examples of combinations of the low-speed flow pipe 31 and the anaerobic tank 41 in the embodiment of FIG. In FIG. 5A, the anaerobic tank 41 is a cylindrical vessel and the low-speed flow conduit 31 is a conical pipe. FIG.
In (B), the anaerobic tank 41 is a polygonal container (eg, a rectangular container) and the low-speed flow conduit 31 is a circular tube. FIG.
In (C), the anaerobic tank 41 is a cylindrical vessel, and the low-speed flow conduit 31 is a polygonal pipe (eg, a square pipe). FIG. 5 (D)
The anaerobic tank 41 is a polygonal container and the low-speed flow line 31
Consists of a polygonal tube. The anaerobic tank 41 shown in FIG.
Is a cylindrical container, and the low-speed flow conduit 31 is a polygonal pyramid tube. In FIG. 5F, the anaerobic tank 41 is a polygonal container, and the low-speed flow conduit 31 is a polygonal pyramidal tube. As the above-mentioned combination (not shown), there is a combination in which the low-speed flow conduit 31 shown in FIGS. FIG.
Items omitted from the description of the low-speed flow pipe 31 and the anaerobic tank 41 in (F) are the same as or similar to the contents described above.

FIGS. 6 and 7 show another embodiment of the present invention, which illustrates a wastewater treatment apparatus mainly composed of a horizontal slow flow pipe 31 and a horizontal anaerobic tank 41. FIG. The configuration in this embodiment is as follows.

Referring to FIGS. 6 and 7, the horizontal low-speed flow channel 31 has both ends closed, and a plurality of water passages 34 in the form of holes are formed on the lower surface of the low-speed flow channel 31. I have.
The horizontal anaerobic tank 41 has a horizontally long container shape and has an open upper surface. In the relationship between the low-speed flow pipe 31 and the anaerobic tank 41, the low-speed flow pipe 31 disposed above (or inside) the anaerobic tank 41 is horizontally supported via a fixture 38 or the like. As shown by the solid lines in FIGS. 6 and 7, the leading end of the drainage pipe 21 is connected to the upper surface of one end of the low-speed flow pipe 31, or as shown by the phantom line in FIG. Is one end (extended part) of low-speed flow conduit 31
Or be connected to In addition, in the embodiment of FIGS. 6 and 7, the anaerobic tank 41 is filled with the above-described filter medium 42. The drainage line 21 and the low-speed flow line 3 in the illustrated example.
1. The point that the anaerobic tank 41 is embedded in the aerobic stratum 11 on the anaerobic stratum 12 is almost the same as the previous example. 6 and 7 are the same as or similar to the previous example.

Since the wastewater treatment apparatus shown in FIGS. 6 and 7 is as described above, the wastewater flows in the order of drainage line 21 → low-speed flow line 31 → anaerobic tank 41 → aerobic formation 11 → anaerobic formation 12. In the process, the first to fourth step processes similar to those described above are performed, whereby the wastewater is purified.

[0038]

The wastewater treatment method and wastewater treatment apparatus according to the present invention have the following effects.

The wastewater repeatedly undergoes aerobic and anaerobic conditions while undergoing the treatment from the first step to the fourth step, and various pollutants in the wastewater are decomposed by various microorganisms. In other words, wastewater subjected to this series of treatments can efficiently decompose and remove water pollutants by aerobic bacteria, anaerobic bacteria, denitrifying bacteria, and other microorganisms. The degree of nitriding is also improved. Dephosphorization from wastewater can also be dealt with with filter media. As a result, the clarified treated water is recharged as groundwater or oozes into rivers and the like, so that water pollution in surrounding water areas hardly occurs. In addition, soils such as aerobic and anaerobic formations are protected from contamination by various and abundant underground microorganisms, and are improved into fertile soils suitable for plant growth.

When treating wastewater by such means,
Since it is only necessary to bury a simple tank in the shallow ground or simply pipe it, the equipment cost is not increased, the operation cost is unnecessary, and the cost for maintenance is hardly required. And the installation space is small. Inexpensive wastewater treatment equipment leads to widespread use of purification equipment, which prevents the discharge of untreated wastewater and the dumping of sewage, thereby further contributing to the safety and preservation of water systems.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically illustrating a vertical embodiment of the method and the apparatus of the present invention.

FIG. 2 is a partial cross-sectional view of the slow flow line illustrated in FIG. 1;

FIG. 3 is a perspective view schematically showing another example of the low-speed flow channel in the present invention.

FIG. 4 is a partial longitudinal sectional view of the low-speed flow line illustrated in FIG. 3;

FIG. 5 is a perspective view and a plan view schematically showing various examples of a combination of a low-speed flow tube and an anaerobic tank in the present invention.

FIG. 6 is a perspective view schematically illustrating a horizontal embodiment of the method and the apparatus of the present invention.

FIG. 7 is a longitudinal sectional side view of the embodiment illustrated in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Aerobic stratum 12 Anaerobic stratum 21 Drainage line 31 Low-speed flow line 32 Channel-shaped member 33a Holding groove 33b Holding groove 34 Water inlet 35 Closing member 36 Connection port 37 Lid 38 Fixing tool 41 Anaerobic tank 42 Filter material

Claims (5)

[Claims] The drainage in the drainage line and the low-speed flow line until the wastewater that proceeds in the order of the drainage line, the low-speed flow line, and the anaerobic tank buried in the aerobic formation flows into the anaerobic tank. Primary treatment process of treating anaerobic bacteria with anaerobic bacteria, and treating the primary treated water with anaerobic bacteria in the anaerobic tank while the primary treated water flowing into the anaerobic tank from the low-speed flow pipe is stagnant in the anaerobic tank When the level of water in the anaerobic tank rises due to the secondary treatment step and the incoming water that flows in later, the secondary treatment water that overflows from the anaerobic tank and permeates the aerobic stratum, A tertiary treatment step of treating water with aerobic bacteria in the aerobic stratum, and when the tertiary treated water infiltrates the anaerobic stratum below the aerobic stratum, the infiltrated tertiary treated water is subjected to anaerobic bacteria in the anaerobic stratum And a quaternary processing step Waste water treatment method characterized by. 2. A drain pipe for introducing drain water, a vertical low-speed flow pipe having a water inlet at a lower portion, and a vertical anaerobic tank having an open upper surface, and a drain pipe. The tip of the passage is connected to the low-speed flow pipe and they are in communication with each other, and the vertical low-speed flow pipe is disposed in the vertical anaerobic tank, and these low-speed flow pipe and anaerobic tank Are connected to each other through a water inlet. 3. Each of the plurality of pipes is composed of a groove-shaped member having a part of the peripheral surface opened and a closing member closing an open peripheral surface of the groove-shaped member. One connection port is formed, and a plurality of pipes are vertically connected to form a low-speed flow pipe, and the drain pipe is connected to the low-speed flow pipe through the connection port. 3. The wastewater treatment device according to claim 2, wherein the wastewater treatment device is connected to a pipe. 4. A plurality of pipes are connected in a vertical direction to form a low-speed flow pipe, a connection port is formed in one of these short pipes, and a drain pipe is provided. 3. The wastewater treatment device according to claim 2, wherein the passage is connected to the low-speed flow conduit through a connection port. 5. A drain pipe for introducing waste water, a horizontal low-speed flow pipe having a water inlet on a lower surface and having both ends closed, and a horizontal anaerobic tank having an open upper surface. And that the end of the drainage line is connected to the low-speed flow line so that they communicate with each other, and that the horizontal low-speed flow line has at least the lower part thereof disposed in the horizontal anaerobic tank. A wastewater treatment device, wherein the low-speed flow pipe and the anaerobic tank communicate with each other via a water inlet.