JP2001038386A - Structure of reaction vessel of waste water treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the treating time in respective reaction vessels to an appropriate value and to prevent deterioration of treatment performance due to time fluctuation of water quality and water quantity of waste water by making a partitioning wall a movable wall which changes the volume of reaction vessels in the waste water treatment device having the plurality of reaction vessels which are divided by the partitioning wall. SOLUTION: Side-ditches 3-5 for fixing the movable partitioning wall 2 are disposed in the reaction vessel 1 of the waste water treatment device which removes organic material from the waste water and the reaction vessel 1 can be divided into the plurality of reaction vessels by the partitioning wall 2. The partition wall 2 is pulled up by means of a chain or a wire, is dropped into either of the side-ditches 3-5 and, thereby, is moved to the upstream side or the down stream side of a water stream. Therein, the time of moving the partitioning wall 2 is set to be the time when treatment performance of the waste water treatment device is reduced, that is, at least one of total nitrogen, ammonia-nitrogen, nitrate-nitrogen, nitrite-nitrogen, total phosphorus, phosphate ion or the like is measured as an index and, when the index exceeds the set value, the movement of the partitioning wall 2 is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates generally to the field of sewage and wastewater treatment, and more particularly to an apparatus for removing nitrogen from wastewater.

[0002]

2. Description of the Related Art An activated sludge process is a typical conventional process for removing organic substances from wastewater, and a biological nitrification and denitrification method is a conventional method for simultaneously removing nitrogen compounds and organic substances. .

FIG. 8 shows an example of a wastewater treatment apparatus based on the biological nitrification and denitrification method. A wastewater treatment apparatus based on the biological nitrification and denitrification method includes a nitrification tank 14 for oxidizing (nitrifying) nitrogen compounds in a sedimentation basin 12 and wastewater to nitrate nitrogen or nitrite nitrogen first, and a nitrate nitrogen or nitrite nitrogen. A denitrification tank 13 for reducing (denitrifying) nitrogen to nitrogen and a final sedimentation tank 17. After removing relatively large and heavy solids contained in the wastewater 11 in the first sedimentation basin 12, nitrogen in the wastewater passes through reactions in the nitrification tank 14 and the denitrification tank 13 and finally in the form of nitrogen gas. It is removed from the wastewater by being released into the atmosphere. The organic matter in the wastewater is stored in the denitrification tank 1
3 and the nitrification tank 14.

A partition wall 2 is installed at a fixed position for a partition between the reaction tanks 13 and 14 in a wastewater treatment apparatus having a plurality of reaction tanks 13 and 14 typified by a biological nitrification and denitrification wastewater treatment apparatus. This is generally done by doing

[0005] The temporal fluctuations in the quality and quantity of drainage water include inter-annual fluctuations (mainly fluctuations caused by changes in the population and the number of factories in the catchment area) and seasonal fluctuations (water usage in each season) depending on the fluctuation cycle. Changes due to changes), daily fluctuations (fluctuations caused by changes in water usage daily), and time fluctuations (fluctuations caused by changes in water usage every hour of the day), and the like. Conventionally, a partition wall is installed at a fixed position to separate the adjoining denitrification tank volume and the nitrification tank volume in response to the time variation of the water quality and amount of these wastewaters. The operation management method of changing the flow rate of the liquid and the flow rate of the returned sludge has been used.

[0006]

However, there is a certain limit to the capacity of the pump for performing these and the sludge concentration in the circulated / returned liquid, and since the partition wall is fixed, the reaction is difficult. The tank volume does not become a factor for changing the operation management conditions, and there is a problem that the flexibility in changing the operation management conditions according to the quality and quantity of the wastewater is insufficient.

[0007] In particular, in nitrogen removal treatment from wastewater using a wastewater treatment facility by biological nitrification and denitrification, fluctuations in the quality and amount of wastewater greatly affect the treatment results. The biological nitrification and denitrification reaction is composed of two reactions by a microorganism, namely, a nitrification reaction and a denitrification reaction. In order to obtain a good nitrogen removal treatment result, these two reactions are caused to occur in a well-balanced manner. It is necessary. When the nitrification reaction is insufficient, even if the denitrification reaction proceeds sufficiently, the organic nitrogen or ammonia nitrogen remains in the treated water, so that the total nitrogen is not sufficiently removed and the denitrification reaction is insufficient. Because nitrate nitrogen or nitrite nitrogen remains in the treated water even if the nitrification reaction proceeds sufficiently,
Total nitrogen is not removed well. When such a problem is viewed in relation to, for example, fluctuations in the quality of wastewater, the BOD of wastewater
When the ratio of / TN becomes higher, the BOD acts as a reducing agent for the progress of the denitrification reaction, so that the denitrification reaction proceeds more easily. From the viewpoint of survival competition through the difference in the growth rate with the removed bacteria, B having a higher growth rate than the nitrifying bacteria
Since the OD-removing bacteria are rapidly multiplied by being given more BOD and become dominant in the nitrification tank, the nitrification reaction hardly progresses after all. Conversely, BOD / T of wastewater
When the ratio of -N becomes low, the growth of nitrifying bacteria becomes BO
Since the factor of losing the growth of the D-removing bacteria is reduced, the nitrification reaction can easily proceed.
Deficiency makes the denitrification reaction difficult to proceed.

[0008] In the nitrogen removal treatment of wastewater by the conventional biological nitrification and denitrification method as shown in Fig. 8, the activated sludge concentration in the denitrification tank 13 and the nitrification tank 14 is almost the same, It is difficult to sufficiently control the balance between the nitrification reaction and the denitrification reaction by changing the temperature.

The present invention proposes a specific method for addressing the above-mentioned problems in a wastewater treatment apparatus having a plurality of reaction tanks, represented by a wastewater treatment apparatus based on a biological nitrification and denitrification method. It is another object of the present invention to provide a wastewater treatment apparatus capable of preventing deterioration in treatment performance due to fluctuations in the quality and amount of wastewater.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and in a wastewater treatment apparatus having a plurality of reaction tanks divided by a partition wall, the partition wall is used to reduce the volume of the reaction tank. This object has been achieved by a wastewater treatment apparatus characterized in that the wall can be changed and relocated.

In the wastewater treatment apparatus according to the present invention,
For example, by providing a plurality of side grooves for fixing the partition wall to the inner wall of the reaction tank, lifting the partition wall with a crane as necessary, suspending and moving, and dropping the partition wall from the upper part of the reaction tank into a side groove at a predetermined position, thereby obtaining a predetermined groove. The partition wall shall be fixed at the position. If the quality and amount of wastewater fluctuate and the flow rate of the nitrifying liquid and the return sludge cannot be changed due to the change and the treatment performance of the wastewater treatment equipment deteriorates, this partition wall is lifted. The position of the partition wall is moved to the upstream side or the downstream side in the reaction tank by dropping the partition into the side groove having the position, and the volumes of the two reaction tanks separated by the partition wall are respectively changed. In this way, by using a partition wall that can be relocated as a partition wall between the reaction tanks, the volume of the reaction tank can be easily changed as necessary, the processing time in each reaction tank is controlled to an appropriate value, and the quality of the wastewater is controlled. In addition, the processing performance is prevented from deteriorating due to the time variation of the amount of water.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The wastewater treatment apparatus of the present invention is an apparatus for removing organic substances and the like in wastewater using a biological reaction. The reaction tank is a denitrification tank, a nitrification tank, an anaerobic tank, an oxygen-free tank, Aerobic tank, etc. Each of these tanks may be a single tank, or may be formed from a plurality of tanks.

The transferable partition wall of the present invention does not partition between tanks of the same type, but partitions between tanks having different reactions. Specifically, for example, it is a partition wall that separates a denitrification tank and a nitrification tank or an anaerobic tank and an aerobic tank.

As means for transferring the removable partition wall, the partition wall is pulled out vertically and moved to drop it to the relocation location, or the partition wall is contracted as a structure that can be retracted in the horizontal direction and moved to the relocation position. Therefore, expansion can be adopted. As a method for fixing the partition wall, a groove or a projection may be used. The groove may be only a vertical groove. When the groove is formed by parallel ridges, it may be the entire length of the side surface or may be partial. The transfer range of the partition wall that can be moved is the denitrification tank and the nitrification tank or the anaerobic tank and the aerobic tank in the volume ratio (the ratio of the volume below each water surface) to the anaerobic tank 1 and the aerobic tank 1 to
A range of about 10, usually about 3 to 8 is appropriate.

FIG. 1 is a perspective view and FIG. 2 is a plan view of an example of a reaction tank of the wastewater treatment apparatus according to the present invention. Further, a perspective view of an example of a reaction tank of a conventional wastewater treatment apparatus is as shown in FIG. The present invention will be described in detail with reference to these drawings.

The reaction tank of the wastewater treatment apparatus according to the present invention comprises:
As shown in FIG. 1, a reaction chamber 1 has side grooves 3, side grooves 4 and side grooves 5 for fixing a partition wall 2, and the reaction tank 1 is divided into a plurality of reaction tanks by the partition wall 2. It has a structure. By lifting the partition wall 2 with a chain or a wire and dropping it into any of the side grooves 3, 4 and 5, the partition wall 2 can be moved upstream or downstream of the water flow. The water in the reactor is
By overflowing the partition wall 2 or passing through a communication port provided in the partition wall 2, the air is sent from the upstream side to the downstream side of the partition wall.

Further, in the reaction tank of the wastewater treatment apparatus according to the present invention, as shown in FIG. 3, the partition wall is constituted by a plurality of plate-like parts (partition wall 2a and partition wall 2b), The partition wall may be configured with parts having a size and weight suitable for the work of lifting from the side groove and dropping into the side groove. In addition, as shown in FIG. 4, in order to fix and hold a wire rope, a chain, and the like used when moving a plate-like component constituting a removable partition wall with a crane, a projecting object is formed on the plate-like component. Has the convenience in the transfer operation of the partition wall. Such protrusions may be provided on both front and back surfaces of the plate-shaped part, or a plurality of protrusions may be fixedly provided. Further, the plate-like component constituting the partition wall which can be relocated has an opening as shown in FIG. 5, or has a notch as shown in FIG. Is that
Since it is useful to fix and hold a wire rope or the like used when moving the plate-like component by using a crane, it provides convenience in the transfer operation of the partition wall, and mixes sludge through the configured partition wall. The liquid can be distributed.

The transferable partition wall is moved when the treatment capacity of the wastewater treatment apparatus is reduced, and the total effluent water, ammonia nitrogen, nitrate nitrogen, nitrite nitrogen, and total phosphorus of the effluent from the treatment apparatus are reduced. , Phosphate ion or the like as an index, and the measurement may be performed when the measured value exceeds a set value. This set value is determined in principle so that the effluent of the wastewater treatment apparatus does not exceed the drainage standard. The measurement point of the index may be effluent from a denitrification tank, a nitrification tank, an anaerobic tank, an aerobic tank, or the like, instead of the effluent from the processing apparatus. In that case, the relationship with the properties of the effluent of the treatment apparatus is checked in advance.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of wastewater treatment using a reaction tank of a wastewater treatment apparatus according to the present invention will be described below. Using the reactor according to the present invention shown in FIG. 1 and the reactor according to the prior art shown in FIG. 7, the performance of removing nitrogen from wastewater was investigated.

In this embodiment, in both the reaction tank according to the present invention and the reaction tank according to the prior art, the reaction tank upstream of the water flow was a denitrification tank and the reaction tank downstream was a nitrification tank.

Table 1 shows the operating conditions.

[Table 1]

In the reaction tank according to the present invention, since the position of the partition wall can be moved, the volumes of the denitrification tank and the nitrification tank were set as follows based on the analysis result of the treated water. When ammonia nitrogen is detected in the treated water, the partition wall is moved so that the denitrification tank volume becomes 15 L and the nitrification tank becomes 25 L. When ammonia nitrogen is not detected in the treated water, the partition wall is moved so that the denitrification tank volume becomes 25 L and the nitrification tank becomes 15 L.

Table 2 shows the average values of the results of the water quality analysis of the wastewater and the treated water.

[Table 2]

As shown in Table 2, the total nitrogen concentration (TN) of the treated water of the reactor according to the present invention was lower than that of the reactor according to the prior art. In addition, the ammonia nitrogen concentration and the sum of the nitrite nitrogen concentration and the nitrate nitrogen concentration (NO _x -N) of the treated water of the reaction vessel based on the prior art are lower than those of the reaction vessel based on the prior art. became. Therefore, using the reaction tank according to the present invention to change the denitrification tank volume and the nitrification tank volume at any time according to the fluctuation of the treated water quality caused by the fluctuation of the inflow water quality and the water amount is equivalent to the processing water T
The result was found to be effective in reducing the -N concentration.

[0025]

In the wastewater treatment apparatus according to the present invention, a partition wall which can be relocated is used as a partition wall between reaction tanks. By moving the water flow upstream or downstream of the water flow, the volumes of the two reaction tanks separated by the partition wall are changed. Thereby, there is an effect that the processing time in each reaction tank is controlled to an appropriate value, and the deterioration of the processing performance due to the time variation of the quality and amount of the wastewater can be prevented.

[Brief description of the drawings]

FIG. 1 is a perspective view of a reaction tank of a wastewater treatment apparatus according to one embodiment of the present invention.

FIG. 2 is a plan view of the reaction tank.

FIG. 3 is a perspective view of a reaction tank of a wastewater treatment apparatus according to another embodiment of the present invention.

FIG. 4 is a perspective view of an example of a partition wall.

FIG. 5 is a perspective view of another example of the partition wall.

FIG. 6 is a perspective view of still another example of the partition wall.

FIG. 7 is a perspective view of an example of a conventional reaction tank.

FIG. 8 is a diagram showing a configuration of an example of a biological nitrogen removing device.

[Explanation of symbols]

 1. Reaction tank 2, 2a, 2b. Partition wall 3. Gutter 4. Gutter 5. Gutter 6. 6. Attachment holes for wire rope, etc. Opening 8. Notch 11. Wastewater 12. First settling basin 13. Denitrification tank 14. Nitrification tank 15. Diffuser 16. Nitrification circulating fluid 17. Final sedimentation basin 18. Returned sludge 19. Treated water

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toyoshi Sawada 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Masahisa Tanabe 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Sun (72) Inventor's Bureau Toshiaki Inventor Bureau 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Jun Miyata 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Inside (72) Inventor Kei Kei Baba 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Satoru Udagawa 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Tatsuo Takechi 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. F-term (reference) 4D028 AA08 BC01 BC18 BC28 4D040 BB52 BB65

Claims (2)

[Claims] 1. A wastewater treatment apparatus having a plurality of reaction tanks separated by a partition wall, wherein the partition wall is a transferable wall that changes the volume of the reaction tank. 2. The wastewater treatment apparatus according to claim 1, wherein a plurality of grooves are provided in the longitudinal direction on the opposite inner wall of the reaction tank, and the partition wall can be relocated by dropping into the respective grooves.