JP2002239592A - Apparatus for treating organic wastewater and treatment method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an equipment and operation cost of an apparatus by performing both a nitrification process and a denitrification process in the apparatus having only one treatment tank to remove nitrogen in addition to the removal of BOD. SOLUTION: One treatment tank 2 is partitioned into a nitrification part 4 on an inlet side and a denitrification part 5 on an outlet side by a microorganism carrier part 3 formed by supporting a large number of string-like carriers 6 by a support frame. In the nitrification part 4, wastewater to be aerated by an aeration pump 9 is aerated to be held to an aerobic state to perform nitrification while generating a convection and the denitrification part 5 is formed so as to have volume larger than that of the nitrification part 4 and partitioned from the nitrification part 4 by the microorganism carrier part 3 to be held to an anaerobic state to perform denitrification.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for purifying organic wastewater using microorganisms. The present invention relates to a simple structure in which a treatment tank is partitioned by a microorganism carrier, whereby nitrification and denitrification of wastewater can be performed in one tank. The present invention relates to an apparatus and a method for purifying organic wastewater that can be performed. In this specification, wastewater to be introduced into the treatment tank to be treated is referred to as “drainage”, and water being treated or treated in the treatment tank is referred to as “treated water”.

[0002]

2. Description of the Related Art Techniques for biologically removing nitrogen components in treated water using microorganisms include a nitrification method for oxidizing ammonium nitrogen to nitrate nitrogen by nitrifying bacteria, and a denitrifying bacterium. There is a denitrification method aimed at reducing nitrous acid and nitrate nitrogen to nitrogen by using the method, and a method combining them is called a nitrification denitrification method.

[0003] This biological nitrification and denitrification method uses organic nitrogen,
A wide range of nitrogen compounds, such as ammonia nitrogen, nitrite and nitrate nitrogen, are targeted, and the form of nitrogen after treatment has the characteristic that there is no worry of secondary pollution,
Generally used widely.

FIG. 4 is a schematic view of a conventional general nitrification and denitrification wastewater treatment system. The wastewater treatment system is a two-tank system including a first tank for performing a nitrification step and a second tank for performing a denitrification step. The first tank feeds air with a blower pump or the like, keeps the aerobic state, and treats ammonia-nitrogen with microorganisms to oxidize it into nitrite or nitrate-nitrogen. Then, the treated water treated in the first tank is led to a second tank maintained in an anaerobic state, where nitrous acid and nitrate nitrogen are reduced to nitrogen and removed.

[0005] Further, they have found that nitrifying bacteria and denitrifying bacteria coexist in the carrier even in an atmosphere containing little organic matter, and it is possible to perform single-tank nitrification denitrification using this symbiotic carrier as shown in FIG. It has already been introduced and publicly known that the nature has been studied fundamentally (NTS Corporation,
See "New Water Treatment Series Water Treatment by Microbial Immobilization", pages 123-124. ).

[0006]

As described above, the conventional two-tank type general nitrification denitrification wastewater treatment system requires two tanks to maintain contradictory states such as an aerobic state and an anaerobic state. Therefore, there has been a problem that the equipment and operation are complicated, and the construction cost and operation cost are increased.

[0007] In the single-tank nitrification denitrification, it takes time and effort to entrap and fix microorganisms on a carrier, and the cost is increased. Further, there is no guarantee that water permeates the carrier. Therefore,
An anoxic tank must be installed as a post-treatment to promote denitrification.

An object of the present invention is to solve the above-mentioned conventional problems, and it is possible to effectively perform nitrification and denitrification of wastewater in only one tank by a simple structure in which a treatment tank is partitioned by a microorganism carrier. It is an object of the present invention to realize an organic wastewater purification treatment device and treatment method that can be performed.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an organic wastewater treatment apparatus for nitrifying and denitrifying organic wastewater comprising a treatment tank and a microorganism carrier, wherein the treatment tank comprises: Provided is an organic wastewater treatment device characterized by being partitioned by a microorganism carrier part.

[0010] The microorganism carrier is characterized in that it has a structure through which treated water in the treatment tank can pass.

One of the treatment tanks partitioned by the microorganism carrier is maintained in an aerobic state, and the other is maintained in an anaerobic state.

One of the treatment tanks partitioned by the microorganism carrier is maintained in an aerobic state by aeration of treated water, and the other of the treatment tanks is maintained in an anaerobic state by partitioning by the microorganism carrier. It is characterized by being performed.

In the treatment tank, wastewater to be treated is introduced into the side maintained in the aerobic state, and treated water is discharged from the side maintained in the anaerobic state.

[0014] The microbial carrier portion comprises a microbial carrier wall composed of at least one carrier selected from the group consisting of a string-shaped carrier, a mesh-shaped carrier, a lattice-shaped carrier, a granular carrier and a porous carrier.
Alternatively, two or more are provided.

In order to solve the above-mentioned problems, the present invention solves the above-mentioned problem by partitioning a treatment tank with a microorganism carrier, maintaining one in an aerobic state and the other in an anaerobic state. And a method for treating organic wastewater.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an apparatus and method for treating organic wastewater according to the present invention will be described below based on embodiments with reference to the drawings. The present invention relates to an apparatus and a method for treating organic wastewater that can simultaneously perform nitrification and denitrification in only one tank in an apparatus for nitrifying and denitrifying organic wastewater using microorganisms.

FIG. 1 is a view for explaining an embodiment of an organic wastewater treatment apparatus and method according to the present invention. An organic wastewater treatment apparatus 1 according to the present invention has one treatment tank 2. It features a tank type nitrification and denitrification system. The treatment tank 2 is partitioned by a microorganism carrier 3 into a nitrification section 4 on the inlet side (upstream side) and a denitrification section 5 on the outlet side (downstream side).

The microorganism carrier portion 3 is configured such that a string-like carrier 6 carrying microorganisms is mounted on the support frame 7. Various structures can be considered for the specific structure of the microbial carrier 3.
A plurality of string-shaped carriers 6 are attached to the support frame 7 so as to allow passage therebetween, thereby forming a microorganism carrier wall 3 ′. The microorganism carrier portion 3 is constituted by the microorganism carrier wall 3 ′. As will be described later, the microorganism carrier section 3 may be composed of a plurality of microorganism carrier walls 3 '. Microorganisms including nitrifying bacteria adhere and grow on the surface of the string-shaped carrier 6 to form a microbial membrane.

In the nitrification unit 4, an inlet 8 for introducing wastewater to be treated is provided at the upper part of the treatment tank 2, and a detonation pump 9 is provided at the bottom of the treatment tank 2. The detonation pump 9 aerates the inside of the nitrification unit 4 to generate a convection (water flow) as indicated by an arrow in the nitrification unit 4,
It is configured to keep the inside aerobic.

The denitrification section 5 is formed in a larger volume (space) than the nitrification section 4, and an outlet through which treated water (treated water) overflows and is discharged above the treatment tank 2 at the downstream end. 10 are provided. Since the nitrification part 4 is aerated, convection occurs. However, the liquid containing a large amount of dissolved oxygen hardly reaches the denitrification part 5 because the cord-shaped carrier 6 hinders the denitrification part 5. Will be kept.

The operation and method of the organic wastewater treatment apparatus according to the present invention having the above-described structure will be described. The wastewater to be treated is introduced from an inlet 8. Explosive pump 9
Aerating the inside of the nitrification unit 4 to maintain an aerobic state by aeration, and also generates convection in the treated water introduced into the nitrification unit 4 as shown by an arrow.

When waste water is newly introduced into the nitrification section 4,
Treated water circulated by convection and subjected to nitrification treatment, which will be described later, is gradually pushed out, passes through the gaps between the cord-shaped carriers 6, and moves to the denitrification unit 5 maintained in an anaerobic state.

As described above, the treated water circulating in the nitrification section 4 due to convection comes into contact with the microbial membrane of the string-shaped carrier 6 while circulating. As a result, the ammonia nitrogen contained in the treated water is oxidized by nitrifying bacteria in the microbial membrane to become nitrite or nitrate nitrogen. This is represented by the following chemical formula. NH ₄ ⁺ +3/2 O ₂ → NO ₂ ⁻ + H ₂ O +2
H ⁺ or NO ₂ ⁻ + 1 / 2O ₂ → NO ₃ ⁻

When the treated water that has been nitrified in the nitrification section 4 passes through the gap of the cord-shaped carrier 6 and moves to the denitrification section kept in an anaerobic state, the nitrite or nitrate nitrogen in the treatment water is denitrified. Is reduced anaerobically to become nitrogen and removed. This is represented by the following chemical formula. 2NO ₂ ⁻ + 3H ₂ → N ₂ ↑ + 2H ₂ O +
2OH ^- or ^{_{2NO 3 - + 5H 2 → N}} 2 ↑ + 4H 2 O +
2OH ⁻

As described above, since the nitrogen in the treated water is removed in the denitrification section 5, the nitrogen component in the treated water is reduced.

In the present invention, the denitrification section 5 is separated from the nitrification section 4 by the microorganism carrier section 3 and the capacity of the denitrification section 5 is made larger than that of the nitrification section 4. (Resolved oxygen contamination) can be suppressed to a small extent, and stable denitrification becomes possible.

Also, since the growth rate of nitrifying bacteria is usually about 1/10 of that of BOD oxidizing bacteria, it is necessary to increase the sludge age (about 3 to 5 days). Since bacteria are carried and the outflow of sludge is suppressed, the sludge age can be earned.

Various configurations can be implemented for the structure of the microorganism carrier. In the above embodiment, the microorganism carrier 3 is
Although a single string-shaped microorganism carrier wall 3 ′ made of a string-shaped carrier is configured, as shown in FIG. 2 as a modified example of the embodiment, a plurality of string-shaped microorganism carrier walls 3 ′ (three in FIG. 2). Provided.)
May be configured. In this case, if the microbial carrier wall on the aerobic side is configured to support nitrifying bacteria at a high density, and the anaerobic microbial carrier wall is configured to support nitrifying bacteria at a high density, finer and more efficient nitrification denitrification can be achieved. It becomes possible.

Further, the microorganism carrier wall 3 'constituting the microorganism carrier portion 3 is not limited to the string-shaped carrier 6 as in the above-described embodiment, and various configurations can be implemented. FIG. 3 shows a view of the microbial carrier walls of various structures as viewed from the front.

FIG. 3A shows a microorganism carrier wall composed of a mesh carrier 18 attached to the support frame 7. FIG. 3B shows a microorganism carrier wall composed of a lattice-like carrier 11 attached to the support frame 7. FIG.
(C) shows the granular carrier 1 attached to the support frame 7.
Reference numeral 2 denotes a microorganism carrier wall configured to be accommodated in a container 13 (mesh-shaped or perforated container or the like) through which water can pass.

FIG. 3D shows a microbial carrier wall formed by connecting the granular carriers 14 attached to the support frame 7 in a cord-like manner. FIG. 3E shows the porous carrier 1.
5 shows a microbial carrier wall composed of 5; A plurality of these microorganism carrier walls may be provided as shown in FIG.

FIG. 3 (f) shows a microbe prepared by carrying microorganisms on both sides of the plate 16 and not allowing the plate 16 to completely separate the treatment tank 2 so that treated water passes through the plate 16. 3 shows a carrier wall. That is, the height of the plate 16 is set to a height at which the treated water overflows, or the through hole 17
May be formed so that the treated water passes through the through-hole 16.

The embodiments of the apparatus and method for treating organic wastewater according to the present invention have been described based on the embodiments. However, the present invention is not particularly limited to such embodiments, and claims are not limited thereto. It goes without saying that there are various embodiments within the scope of the technical matters described in the range.

[0034]

According to the apparatus and method for treating organic waste water according to the present invention as described above, the nitrification step and the denitrification step can be performed with a simple treatment apparatus having only one treatment tank. In addition to removing BOD, nitrogen can be removed and the nitrogen component in the treated water can be reduced, and the cost required for the construction and operation of the apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is a view for explaining an embodiment of an apparatus and method for treating organic wastewater according to the present invention.

FIG. 2 is a view for explaining a modification of the embodiment of the apparatus and method for treating organic wastewater according to the present invention.

FIG. 3 is a diagram for explaining various configurations of a microorganism carrier portion in an embodiment of an organic wastewater treatment apparatus and treatment method according to the present invention.

FIG. 4 is a schematic diagram for explaining a conventional general two-tank type organic wastewater treatment system.

FIG. 5 is a schematic diagram for explaining a known one-tank type organic wastewater treatment system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Organic wastewater treatment apparatus 2 Treatment tank consisting of one tank 3 Microorganism carrier part 4 Nitrification part 5 Denitrification part 6 Microorganism carrier 7 Microorganism carrier support frame 8 Inlet for introducing raw wastewater 9 Aeration pump 10 Outlet for extracting treated water DESCRIPTION OF SYMBOLS 11 Lattice carrier 12, 14 Granular carrier 13 Container which can pass water 15 Porous carrier 16 Plate 17 Through hole 18 Reticulated carrier

Claims (7)

[Claims] An organic wastewater treatment apparatus for performing nitrification and denitrification of organic wastewater comprising a treatment tank and a microorganism carrier, wherein the treatment tank is partitioned by a microorganism carrier. Processing equipment. 2. The organic wastewater treatment apparatus according to claim 1, wherein the microorganism carrier has a structure through which treated water in the treatment tank can pass. 3. The organic wastewater treatment apparatus according to claim 1, wherein one of the treatment tanks partitioned by the microorganism carrier is maintained in an aerobic state, and the other is maintained in an anaerobic state. . 4. One of the treatment tanks partitioned by the microorganism carrier is kept in an aerobic state by aeration of treated water, and the other of the treatment tanks is placed in an anaerobic state by being partitioned by the microorganism carrier. The organic wastewater treatment device according to claim 1, wherein the organic wastewater is kept. 5. The process tank, wherein wastewater to be treated is introduced into the side maintained in the aerobic state, and treated water is discharged from the side maintained in the anaerobic state. Item 5. An organic wastewater treatment device according to item 3 or 4. 6. The microorganism carrier portion comprises one or more microorganism carrier walls comprising at least one or more carriers selected from a string carrier, a mesh carrier, a lattice carrier, a granular carrier and a porous carrier. Claim 1, characterized in that
The organic wastewater treatment apparatus according to 2, 3, 4, or 5. 7. The treatment tank is partitioned by a microorganism carrier, and one is kept in an aerobic state and the other is kept in an anaerobic state,
A method for treating organic wastewater, wherein nitrification and denitrification of organic wastewater are performed in the treatment tank.