JP2003211185A - Powerless wastewater treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a powerless wastewater treatment method for removing organic matter and/or nitrogen in wastewater by natural ventilation by forming a gas-liquid separation interface between wastewater and the atmosphere through an oxygen permeable membrane. <P>SOLUTION: The powerless wastewater treatment method is constituted so as to remove organic matter and/or nitrogen in wastewater by natural ventilation by forming the gas-liquid separation interface between wastewater and the atmosphere through the oxygen permeable membrane and includes at least a process (1) for taking atmospheric oxygen in wastewater through the oxygen permeable membrane to aerobically treat organic matter by the biological film generated on the surface of the membrane, a process (2) for oxidizing ammonia nitrogen in wastewater to form nitrate nitrogen and a process (3) for diffusing nitrate nitrogen into wastewater held under an anaerobic environment going away from the biological film to perform denitrification reaction. Herein, the oxygen permeable membrane is formed into a cylindrical or tubular shape and arranged in the atmosphere while wastewater is introduced into the hollow part of the membrane or arranged in wastewater while the atmosphere is introduced into the hollow part of the membrane. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to non-powered wastewater treatment for sewage and other wastewater, and more specifically to non-powered equipment for removing organic matter and / or nitrogen in wastewater by natural aeration using an oxygen permeable membrane. Regarding wastewater treatment method.

[0002]

2. Description of the Related Art Conventionally, in wastewater treatment facilities, oxygen has been supplied to sewage and other wastewater to treat organic substances. Here, oxygen supply often depends on aeration, and power for air supply is required.

Since it is also necessary to reduce nutrient salts such as nitrogen as a countermeasure against eutrophication, it is necessary to supply a hydrogen donor (eg, methanol).

Therefore, it was not possible to suppress the facility cost and the operating cost (including the energy cost) by ignoring them. The equipment cost is for a fixed facility attached with a power source.

By the way, the oxidation pond method (lagoon method) is known as a wastewater treatment method that does not require oxygen supply energy at all, but it requires a long period of one month or more, or a vast area. In this respect, the current situation is that it has not been put to practical use in Japan.

[0006]

However, when it is desired to reduce not only organic substances in wastewater but also nutrient salts such as nitrogen, wastewater treatment technology becomes more complicated and sophisticated, and cost reduction is difficult. It is supposed to be.

Under these circumstances, the inventors of the present invention can be economically applied to reduction of equipment costs and running costs (including energy saving) and can be flexibly applied to areas where it is difficult to supply electricity such as electricity. We have been conducting research and research on non-powered wastewater treatment that has locationality.

[0008] Here, it is necessary to promise a processing capacity equivalent to that of the conventional aeration processing and a reduction of the occupied area.

Then, it has come to be recognized that the development of wastewater treatment technology which is carried out without power is an unsolved technical problem.

The present invention has been made in view of the above circumstances. By utilizing oxygen in the atmosphere, the conventional aeration means is eliminated to perform organic substance treatment, and yet a biofilm is naturally formed. The present invention provides a non-powered wastewater treatment method that combines eutrophication measures by advancing the denitrification reaction.

[0011]

In order to solve the problems, the present invention forms a gas-liquid separation interface between sewage and other wastewater and the atmosphere through an oxygen permeable membrane, and naturally aerates organic matter in the wastewater. And / or a non-powered wastewater treatment method for removing nitrogen, wherein a gas-liquid separation interface is formed between the wastewater and the atmosphere through an oxygen permeable membrane, and atmospheric oxygen is taken into the wastewater by natural aeration, The biofilm generated on the membrane surface aerobically treats the organic matter, oxidizes ammonia nitrogen in the wastewater to generate nitrate nitrogen, and removes the nitrate nitrogen from the biofilm into the wastewater in an anaerobic environment. It is characterized in that it is made to diffuse to carry out a denitrification reaction.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The embodiment of the present invention includes at least the following treatment steps in the above-mentioned configuration as shown in the principle explanatory view of the wastewater treatment mechanism in FIG.

(1) Atmospheric oxygen is taken into the wastewater through the oxygen permeable membrane, and aerobic treatment (CO ₂ separation) of organic matter is performed by the biofilm generated on the membrane surface.

(2) Ammoniacal nitrogen in the waste water is oxidized to produce nitrate nitrogen.

(3) Denitrifying reaction (N ₂ separation) is carried out by diffusing nitrate nitrogen into wastewater in an anaerobic environment away from the biofilm.

(4) Receive the treated wastewater and discharge the treated wastewater to the outside of the system.

Here, whether the oxygen permeable membrane is formed in a tubular shape or a tubular shape, and the hollow portion thereof is introduced with waste water and installed in the atmosphere [intramembrane water flow method described later. ] Or introduced into the atmosphere and installed in drainage [oxygen permeable membrane immersion method. ] To separate gas and liquid. As the material of the oxygen permeable film, a silicone resin or a cloth whose surface is coated with silicone resin can be used.

Therefore, in the construction of the non-powered wastewater treatment equipment, an oxygen permeable membrane which forms a gas-liquid separation interface between the wastewater and the atmosphere is interposed, and atmospheric oxygen is taken into the wastewater by natural aeration so that the membrane surface The generated biofilm performs aerobic treatment of organic matter, oxidizes ammonia nitrogen in wastewater to produce nitrate nitrogen, and diffuses it into wastewater in an anaerobic environment away from the biofilm for denitrification. It will be equipped with a redox mechanism that allows it. [See below]

(Embodiment 1) An intramembrane water flow method which is an embodiment of the present invention [hereinafter, referred to as embodiment method 1. 2 is shown in FIG.

As shown in the drawing, in the method 1 of the embodiment, waste water (hereinafter, sewage) is passed through the membrane tube, and organic substances and nitrogen are removed during the passage.

The processing step (or processing mechanism) is as described above, but will be specifically described according to the apparatus configuration shown.

(1) In the immediate vicinity (inner wall) of the tubular oxygen permeable membrane, aerobic microorganisms utilizing oxygen diffused from the atmosphere grow and form a biofilm.

(1 ') Organic matter in wastewater is oxidized and decomposed by a biofilm. Nitrogen is also oxidized within this biofilm to produce nitrate nitrogen. (In the figure, near the membrane: aerobic.)

(2) The produced nitrate nitrogen diffuses into the anaerobic part (remote part: anaerobic in the figure) separated from the membrane and is reduced to nitrogen gas by denitrifying bacteria.

(3) The (micro) biofilm generated in the cylinder falls off after growth and is deposited and accumulated as sludge.

(4) Fresh sewage is introduced into the settling tank, and treated water is discharged from the upper part of the cylinder to complete the treatment cycle. And
(5) By repeating the processes of (1) to (4) above, the treatment is continuously advanced.

(Embodiment 2) An oxygen permeable membrane dipping method according to another embodiment of the present invention [hereinafter, embodiment method 2. FIG. 3 shows a device configuration in which the above] is embodied as a technical means.

As shown in the figure, in the method 2 of the embodiment, a tubular oxygen permeable membrane whose both ends are open to the atmosphere in sewage is suspended and immersed in one side (treatment side) of a settling tank provided with a half partition wall. By permeating oxygen from the inside of the membrane tube into the external wastewater, organic substances and nitrogen are removed.

The processing step (or processing mechanism) is the method of Example 1
The same as (1) to (3). In addition, the cylinder should be understood as a tube.

As can be easily seen from FIG. 3, fresh sewage is introduced from one of the upper portions of the settling tank and the other (treatment side).
The treated water is discharged from the upper part of the settling tank to complete the treatment (4). Then, the process is repeated by repeating the above process (5).

For reference, the treatment capacity of the method of the present invention based on experimental facts is shown in Table 1, and the effect of the developed apparatus (method of the present invention) and the combined treatment septic tank (conventional method) is shown in Table 2.

[0032]

[Table 1]

[0033]

[Table 2]

As can be understood from Table 2, the following (a)-
(D) can be considered or evaluated.

(B) Treatment efficiency In the method of the present invention, the concentration of dissolved oxygen in the wastewater is biased,
Since the aerobic part and the anaerobic part are formed in the tank, it is possible to efficiently remove nitrogen in the same tank. On the other hand, in the conventional method, since aeration is performed, the inside of the tank is uniformly aerobic, and the nitrogen removal efficiency becomes low. Therefore, in order to effectively remove nitrogen, it was necessary to separately provide an anaerobic tank to feed the solution.

(B) Oxygen supply In the method of the present invention, since the supply of oxygen depends only on the natural diffusion from the atmosphere, the energy supply in the case of using the power for forced air supply (conventional method) is unnecessary. .

(C) Regarding the amount of sludge generated In the method of the present invention, since the lower layer of the treatment tank is in an anaerobic state, the amount of sludge generated is small. On the other hand, in the conventional method, the amount of sludge produced is large because the aerobic treatment is mainly performed.

(D) Maintenance and operation costs Since the method of the present invention does not have a power source, maintenance is extremely easy and operation costs can be kept low.

[0039]

The present invention has the above-mentioned structure. According to the present invention, it is possible to perform non-powered wastewater treatment for simultaneously removing organic substances and nitrogen that do not require energy by a very simple method. .

Since it is naturally ventilated, the cost is naturally low, and there is no restriction on locality (location conditions) (being mobile).

Therefore, it can be applied as an alternative treatment method for existing wastewater treatment facilities, and can be expected to be promoted as an administrative measure such as cost reduction and expansion of users who need water quality conservation such as natural parks and livestock shelters.

[Brief description of drawings]

FIG. 1 is a principle explanatory diagram of a wastewater treatment mechanism.

FIG. 2 is an explanatory diagram showing a device configuration of an intramembrane water flow method [Example method 1].

FIG. 3 is an explanatory diagram showing an apparatus configuration of an oxygen permeable film dipping method [Example method 2].

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hirofumi Izawa             Hiroshima Prefecture Hiroshima City 10-52 Motomachi Naka-ku Hiroshima Prefecture Ring             Sakai Bureau Environmental Creation Office, Environmental Control Room F-term (reference) 4D006 GA41 HA21 KA31 KB22 KB23                       KB25 MA02 MA10 MB04 MC65                       PB08 PB17 PB62                 4D029 CC03 DD03                 4D040 BB07 BB42 BB63 BB82

Claims (2)

[Claims] 1. A non-powered wastewater treatment method for sewage and other wastewater, wherein a gas-liquid separation interface is formed between the wastewater and the atmosphere through an oxygen permeable membrane, and natural aeration removes organic matter and / or nitrogen in the wastewater. A non-powered wastewater treatment method for removing, which comprises at least the following treatment steps. (1) Atmospheric oxygen is taken into the wastewater through the oxygen permeable membrane, and the aerobic treatment of organic matter is performed by the biofilm generated on the membrane surface. (2) Ammonia nitrogen in the waste water is oxidized to generate nitrate nitrogen. (3) Nitrate nitrogen is diffused into wastewater in an anaerobic environment away from the biofilm to carry out a denitrification reaction. 2. An oxygen-permeable membrane is formed in a tubular shape or a tubular shape, and its hollow portion is introduced with waste water and installed in the atmosphere, or introduced into the air and installed in waste water to separate gas and liquid. The non-powered wastewater treatment method according to claim 1.