JPS61101298A - Trench shaped rainwater treatment apparatus - Google Patents

Abstract

PURPOSE:To enhance oxidation capacity of an org. substance and to attain to reduce cost, by arranging a purification treatment apparatus equipped with both of an aerobic chamber and an anaerobic chamber to a flow channel capable of stably flowing rainwater largely varying in a flow amount. CONSTITUTION:Rain water flows through the flow channel formed by a U-shaped trench 3 to be penetrated into the circumference from a crushed stone layer 2 through a gravel layer 6. Rainwater contains a large quantity of foreign matter or contaminant but aerobic bacteria in soil can be actively propagated in the aerobic chamber 10 of a duct 4 and almost all of org. substances or suspended matters in rainwater can be removed by decompositional treatment. Denitrifying bacteria are actively propagated in the anaerobic chamber of the duct 4 by using carbon C of charcoal 9 as an energy source and decompose ammoniacal nitrogen in rainwater to nitrogen gas.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a trench-type rainwater treatment device that allows purified rainwater to penetrate underground by removing foreign matter and pollutants from the rainwater.

[Technical background of the invention and its problems] As is well known, most of the rainwater flows through lakes and sewers, or is sucked into the ground, but the rainwater that seeps into the ground is stored as groundwater. state.

Therefore, it is desirable to introduce a large amount of rainwater underground as much as possible.
There are deep well methods, etc. The planar diffusion method uses rice fields, ponds, etc., and has the problem of occupying a large area that cannot be used above.

In addition, the water flow that flowed into the area stirred up earth and sand,
As a result, the large and heavy particles settle in order, and the colloidal thin particles settle at the end.As a result, the bottom of the pond, etc. becomes covered with a membrane, creating a so-called clogged state that prevents water from draining. This results in a decline in the ability to penetrate underground. On the other hand, the well exploration method cannot avoid the above-mentioned clogging condition.

Moreover, rainwater that flows down the ground surface and picks up trash and pollutants is no longer sewage, and allowing it directly into the ground will result in further groundwater contamination. For this reason, capillary infiltration trenches are well known in which a shallow trench is filled with pipes, gravel, etc., into which the wastewater is poured and water is sprinkled into the soil.

This does not expect sewage to permeate vertically to the bottom, but to permeate from the side from the trench, and also allows the microorganisms growing in the soil to decompose and process pollutants in the sewage. The purpose is to store water underground as purified water. As a specific known example, a trench-type sewage treatment device is provided, for example, in Japanese Patent Publication No. 57-54193. That is, a tank made of impermeable material is provided at the bottom of the trench, and the gravel is filled to a height beyond the tank, and a gravel layer and a covering soil layer are sequentially placed on top of the sand layer. In a trench-type sewage treatment system in which a wastewater pipe and a porous drainage pipe are provided in the soil covering layer and the soil covering layer, respectively, the boundary between the gravel layer and the covering soil layer is made concave.

As a result, in normal cases, sewage supplied through the sewage pipes permeates by gravity from the gravel layer into the sand layer, and then from the sand layer into the soil around the trench by capillary siphon action, with some of the water coming from the ground surface. It evaporates and the rest is replenished by seepage into groundwater. Furthermore, when sewage is temporarily supplied for a long time, the sewage supplied from the sewage pipe is evenly reverse-filtered through the covering soil layer of approximately the same thickness as it percolates up from the top of the gravel layer to the drainage pipe. .

In the case of trench-type sewage treatment equipment such as the above-mentioned known example, foreign matter and general pollutants in wastewater can be filtered out or decomposed, but in order to activate the growth of microorganisms that decompose these pollutants, the filter media is Aerobicity is important. However, ammonia nitrogen in pollutants is not decomposed by the aerobic microorganisms mentioned above, but instead oxidizes and changes into nitrite nitrogen, which permeates underground and drains groundwater. There was a problem with contamination.

In particular, in the case of rainwater flowing down from the topsoil, it picks up a wide variety of pollutants, so the presence of ammonia nitrogen cannot be ignored, while activating the reproduction of aerobic microorganisms is also essential. A contradictory state is required.

In addition, since the flow rate of rainwater fluctuates greatly, when a large amount of rainwater flows in, it is not possible to deal with the inflow of rainwater using conventional pipes, and in addition, long drainage pipes are required to communicate with the system. In addition, there was a problem in that the equipment cost increased because a drain pipe and a sewage pipe were each required.

[Purpose of the Invention] The present invention has been made in view of the above-mentioned problems, and is a purification process that has both an aerobic chamber and an anaerobic chamber in a flow path that can stably flow rainwater that has a large flow rate fluctuation. A device is attached to make the reproduction of aerobic microorganisms more active and reduce organic matter (BO) in rainwater.
D) The oxidizing ability of (COD) is extremely high, and most of the nitrite nitrogen and nitrate nitrogen are decomposed into nitrogen gas by anaerobic denitrifying bacteria, and the cost is low due to the simple structure. The purpose of the present invention is to provide a trench-type rainwater treatment device that is equipped with the following features.

[Summary of the Invention] In order to achieve the above object, a trench type rainwater treatment device according to the present invention is provided by laying crushed stone at the bottom of a trench, placing a U-shaped groove face down on the surface layer thereof, and Above the U-shaped groove, a purification treatment device comprising an anaerobic chamber filled with charcoal and other sludge and a hollow aerobic chamber is installed, and a PJ layer is installed above the U-shaped groove or the crushed stone layer. It has a structure in which layers of soil and aerated soil are laminated in sequence.

[Structure of the invention] Embodiments of the present invention will be described below based on the drawings.

The trench groove 1 formed underground has a narrow, shallow and long structure similar to well-known ones, and has a width and depth of 600 mm to 60 mm.
It is about 800mm. This is because if the trench groove 1 is too deep, the lateral area increases and the lateral infiltration function increases, but on the other hand, the purification function decreases because there are few microorganisms and plant roots that decompose organic matter, and if the trench groove 1 is made too wide, it will not accumulate water. Although the capacity can be increased, the side penetration function remains unchanged and the space efficiency becomes poor.

In the trench groove 1, one piece of crushed stone 2 is placed at the bottom of the trench groove 1.
A filter bed is formed with a thickness of about 00 to 200 mm. The surface layer of the crushed stone 2 has a U-shaped cross section and a length of 1,000 mm.
Contour type or ceramic U-shaped groove 3 of about mm,
A large number of people are arranged face down to form one flow path, and a predetermined distance A is left between each U-shaped groove 3.

In addition, ventilation pipes 4 are installed between the U-shaped grooves 3 at regular intervals, and the upper end opening of the ventilation vibe 4 is connected to the ground surface (GL
). A duct 5 made of reinforced plastic (FRO) or the like is disposed above the U-shaped groove 3 and is formed to have the same length as the U-shaped groove 3 and an inverted U-shaped cross section.
A gravel layer 6 is laid down to a predetermined thickness on the upper surface of the groove 3 or the upper surface of the crushed stones 2, and the escape aeration soil 8 from the ground surface (GL) is filled through a net 7 stretched over the surface layer. .

Inside the duct 5, an anaerobic chamber is formed by filling the upper chamber with a material that activates denitrifying bacteria, such as charcoal 9 such as charcoal or coal, and the lower chamber is hollow to provide ventilation. This is in the aerobic chamber 10 which is held. Furthermore, duct 4
In the upper part of the duct 4, that is, the top of the anaerobic chamber, a plurality of slits 11 are bored to communicate with the outside, and in the lower part of the duct 4, that is, the side of the aerobic chamber 10, a number of square holes 12 are formed in series. and communicate with the outside.

In the above configuration, rainwater flows through the channel formed by the U-shaped groove 3 and penetrates into the surrounding area through the crushed stone layer 2 to the gravel layer 6. This rainwater contains a large amount of foreign matter and pollutants as described above, but since the aerobic chamber 10 of the duct 4 can make the reproduction of aerobic microorganisms in the soil extremely active, the rainwater contains a large amount of foreign matter and pollutants. Most organic substances (BOD) (COD) and suspended solids (SS) can be decomposed and removed. On the other hand, in the anaerobic chamber of duct 4, denitrifying bacteria can propagate and become more active using the carbon C of the charcoal 9 filled there as an energy source, so that the ammonia nitrogen ( By oxidizing NH3-N), most of nitrite nitrogen (NO2-N> and nitrate nitrogen (NO3-N)) can be decomposed into nitrogen gas.

In this way, the exhaust gas (gas) decomposed and vaporized by microorganisms in the vicinity of the U-shaped groove 3 is diffused and evaporated via the PJ layer 6 and the aerated soil 8, or is transferred from the aeration vibrator 4 to the ground surface (GL).
Since the water is discharged and removed outside the water, only purified water permeates into the groundwater. In this way, the treatment efficiency is greatly improved compared to the conventional trench type treatment equipment, and even if the flow rate of rainwater increases rapidly, the flow path is not a sealed pipe, so the gravel layer 6 Since it will percolate and be stored in the crushed stone 2, there is no risk of causing any trouble.

Moreover, since the U-shaped grooves 3 to which the ducts 4 are attached are simply arranged in the trench groove 1 during construction, the cost of materials can be reduced as well.

[Effects of the Invention] As explained above, according to the present invention, a duct-shaped purification device equipped with an aerobic chamber and an anaerobic chamber is attached to a U-shaped groove, and these are connected at predetermined intervals. Since the trenches are connected in series within the trench, they are suitable for treating rainwater with large fluctuations in flow rate, and most of the organic substances and suspended substances in the rainwater that has become sewage are removed. In addition, nitrite nitrogen, nitrate nitrogen, etc. are decomposed into nitrogen gas by anaerobic denitrifying bacteria, which not only reliably prevents groundwater contamination, but also makes it easy to use during construction. It also has the effect of being inexpensive.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of a trench type rainwater treatment device according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view showing the construction state of the same device. 1...Trench groove 2...Crushed stone (layer) 3...U
Groove 4...Duct 5...Ventilation vibe 6
...Gravel layer 8...Aerated soil 9...Charcoal 10...Aerobic chamber

Claims (1)

[Claims] Crushed stone is laid at the bottom of the trench groove, and a number of U-shaped grooves formed in a U-shape are placed face down on the surface layer, leaving a predetermined gap, and an anaerobic chamber filled with charcoal, etc. A duct-like purification device is attached to the top of the U-shaped groove, in which a hollow aerobic chamber is divided into two layers, upper and lower, and each layer is communicated with the outside. A trench-type rainwater treatment device consisting of a gravel layer of a predetermined thickness and an aerated soil layer layered in sequence on the upper surface.