JPH10323694A - Method for removing nitrogen in water containing nitrate and denitrification bioreactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve operational problems and enable nitrogen removal performance to be improved by conducting nitrogen removal (membrane separation nitrogen removal) at a level of a single body apparatus by using a membrane container in which hydrogen donors are enclosed as a nitrogen removal bioreactor of a cartridge-type. SOLUTION: Water containing nitrate and methanol 2 provided from the outside are membrane-separated in the water containing nitrate. The methanol 2 is allowed to permeate through a membrane 11 to activate a denitrification reaction on a biofilm generated on the surface of the membrane 11. A nitrogen removal bioreactor X includes a membrane container 1 made by forming a polyethylene membrane material 11 into a bag or a tube and in which the methanol 2 is enclosed. The methanol 2 can be supplied from the outside. The nitrogen removal bioreactor X is provided as a cartridge able to be used repeatedly as a single body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing nitrogen from nitrate-containing water by a bioreactor and a denitrification bioreactor.

[0002]

2. Description of the Related Art Conventionally, in the improvement of water quality in a water area in which water pollution is progressing due to eutrophication, nitrate (nitrate nitrogen) contained in domestic wastewater or industrial wastewater, which is one of the causes of pollution, is denitrified. A denitrification bioreactor that biochemically reduces nitrogen gas by bacteria (Hyphomicrobium) is known. (Nitrification and denitrification method)

In the conventional method, as shown in FIG. 4 (a), a hydrogen donor (organic carbon compound) is charged into the same liquid phase (mixed denitrification). A separate removal process was required. In this case, even in clear (low organic carbon concentration) water, an organic carbon compound is once added, a denitrifying bacterium is propagated, denitrification is performed, and then the organic carbon compound is separately removed. Become.

[0004] Biological treatment methods (nitrification and denitrification method) having such a nutrient removal function are more cost-effective to perform at the source level than directly to environmental water in water purification measures. It has advantages, and the device has been developed so far.

[0005]

However, the operation of the entire apparatus must be changed, and as a result, it cannot be applied to existing equipment and existing facilities in many cases. Had to be delayed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and uses a membrane container enclosing a hydrogen donor as a cartridge-type denitrification bioreactor to denitrify (membrane separation denitrification). At the single device level,
An object of the present invention is to provide a method for removing nitrogen from nitrate-containing water and a denitrification bioreactor capable of solving operational problems and improving denitrification performance.

[0007]

SUMMARY OF THE INVENTION In order to solve the problems, the present invention is a method for removing nitrogen from nitrate-containing water by a single denitrification bioreactor. Membrane separation from the hydrogen donor
In addition, the present invention is characterized in that a hydrogen donor is permeated through the membrane to activate a denitrification reaction in a biofilm formed on the membrane surface.

A denitrification bioreactor, wherein a closed compartment is formed in nitrate-containing water, a hydrogen donor is sealed in the closed compartment, and at least one partition wall is constituted by a hydrogen donor permeable membrane. The membrane container is made into a cartridge which can be used repeatedly by itself.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment of the present invention, the hydrogen donor in the above structure is methanol, the hydrogen donor permeable membrane is a polyethylene membrane, and a polyethylene membrane material is formed in a bag or a tube. Methanol is sealed in the membrane container thus formed to constitute a cartridge type denitrification bioreactor.

The function of the denitrification bioreactor having the above structure is that when the methanol inside the container permeates the membrane and reaches the surface, it is taken in by the denitrifying bacterium to reduce nitrate nitrogen and diffuse it as nitrogen gas. For this reason, a biofilm in which the denitrifying bacteria are immobilized at a high density is generated on the membrane surface, and the denitrification reaction is activated here. (Membrane separation denitrification)

Further, since the denitrification bioreactor having the above configuration is a single unit, denitrification at a required place can be advanced at a single unit level.

Therefore, it can be attached to an existing septic tank, and since it is a cartridge type, it can be used repeatedly.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an explanatory view schematically showing the method (membrane separation and denitrification) of the present invention.

FIG. 2 is a schematic diagram showing the structure of the denitrification bioreactor of the present invention.

As shown in the figure, a denitrification bioreactor (X) comprises a membrane container (1) in which a polyethylene membrane material (11) is formed in a bag shape or a tube shape.
Is enclosed. In this case, a net is put in the container (1) to maintain the shape of the container and to suppress the floating and uneven distribution of the methanol (2). The tube in the figure is for externally replenishing methanol (2), the cock is for sealing (plugging), and the shackle is for weight or for hanging the bottom of the tank.

Therefore, the denitrification bioreactor (X)
Can be made into a cartridge.

The denitrification bioreactor (X)
Is placed in the nitrate-containing water to separate the membrane from the nitrate-containing water and methanol, and to permeate the methanol through the membrane. A film can be formed to activate the denitrification reaction.

Here, only the following conclusions will be made regarding the operation and effect of the present invention based on experimental facts.

The denitrification is performed almost only on the film surface. The denitrification rate depends on the characteristics of methanol permeation through the polyethylene membrane. (Both temperature dependent)

FIG. 3 shows an example in which the denitrification bioreactor is applied to an existing actual septic tank (eg, human waste septic tank).
As shown, the denitrification bioreactor (X) is installed in a settling tank.

FIG. 4 (a) shows a conventional method (mixed denitrification).
And (b) is a comparative explanatory view schematically showing the difference between the features of the method of the present invention (membrane separation and denitrification).

[0022]

According to the present invention, the denitrification bioreactor alone can exhibit the denitrification function according to the above constitution, so that it can be efficiently installed at any place whenever necessary Nitrogen can be removed.

Therefore, the range of application can be expanded as a component that plays a part in a purification system for river water and groundwater as well as wastewater treatment by a septic tank.

In addition, capital investment such as conventional securing of land and construction of a denitrification tank is not required, and the manufacturing cost of the apparatus is low, so that a great economic effect such as a reduction in initial investment (installation cost) can be achieved. Can be expected. In addition, it is only necessary to leave the apparatus as it is after installation, so that maintenance can be saved.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a method of the present invention (membrane separation and denitrification).

FIG. 2 is a schematic structural diagram of a denitrification bioreactor.

FIG. 3 is an explanatory diagram showing an example in which a denitrification bioreactor is applied to an existing actual septic tank.

FIG. 4 is a comparative explanatory diagram schematically showing the difference between (a) the conventional method (mixed denitrification) and (b) the method of the present invention (membrane separation and denitrification).

[Explanation of symbols]

 1 Membrane container 11 Polyethylene membrane 2 Methanol X Denitrification bioreactor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C02F 3/10 C02F 3/10 Z

Claims (5)

[Claims] In a method for removing nitrogen from nitrate-containing water by a bioreactor, the nitrate-containing water is separated from the externally supplied hydrogen donor by membrane in the nitrate-containing water, and the hydrogen donor is passed through the membrane. A method for removing nitrogen from nitrate-containing water, wherein the nitrogen is permeated to activate a denitrification reaction in a biofilm formed on the membrane surface. 2. The method for removing nitrogen from nitrate-containing water according to claim 1, wherein the hydrogen donor is an organic carbon compound, and the membrane is a resin-made hydrogen donor permeable membrane. 3. The method for removing nitrogen from nitrate-containing water according to claim 2, wherein the organic carbon compound is methanol and the resin-made hydrogen donor permeable membrane is a polyethylene membrane. 4. A biofilm formed on the surface of a membrane by separating the nitrate-containing water and an externally supplied hydrogen donor by membrane in the nitrate-containing water and allowing the hydrogen donor to pass through the membrane. A denitrification bioreactor for activating a denitrification reaction of a gas, comprising forming a closed compartment in nitrate-containing water, enclosing a hydrogen donor in the closed compartment, and forming at least one compartment wall with a hydrogen donor permeable membrane. A denitrification bioreactor comprising a membrane container constituted by the above (1), wherein the membrane container is a cartridge that can be repeatedly used alone. 5. A hydrogen donor is methanol, a hydrogen donor permeable membrane is a polyethylene membrane, and a membrane container is formed by forming the polyethylene membrane material into a bag or a tube and enclosing the methanol. 5. The denitrification bioreactor according to claim 4, wherein