JP2604958B2 - Nitrification and denitrification equipment by biofilm filtration - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nitrification denitrification apparatus using biofilm filtration, which can efficiently perform a nitrification denitrification treatment of wastewater with a compact apparatus.

[0002]

2. Description of the Related Art For example, wastewater containing organic nitrogen or ammonia nitrogen, such as sewage, is generally subjected to nitrification denitrification by biofilm filtration to be purified. As a denitrification device, a tank 1 as shown in FIG.
An aeration diffuser 2 is disposed therein, and the upper part of the aeration diffuser 2 is a nitrification zone 3 and a lower part is a denitrification zone 4 (see Japanese Patent Publication No. 4-50880). ).

However, in this type of apparatus, since the nitrification zone and the denitrification zone are fixed in a certain area, nitrification is sufficiently performed but denitrification is insufficient depending on the quality of raw water, or vice versa. In addition, there is a problem that the processability is not stable, such as insufficient nitrification but sufficient denitrification. On the other hand, in order to stabilize the processability, it is necessary to make the capacity of each zone sufficiently large, and there is a problem that the equipment must be excessively large.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems and reduces the residence time of raw water in each zone by changing the ratio between the nitrification zone and the denitrification zone. Provide a nitrification denitrification device by biofilm filtration that can be optimized and sufficient nitrification denitrification can be performed, and the processing tank can be downsized and the whole device can be designed to be compact. It was completed for the purpose of doing.

[0005]

In order to solve the above-mentioned problems, a nitrification denitrification apparatus using biofilm filtration according to the present invention is provided with an aeration device in a tank. In the nitrification denitrification apparatus by biofilm filtration with the upper part being a nitrification zone and the lower part being a denitrification zone, the aeration diffuser is provided with a plurality of vertically diffusing members arranged in a tank in a vertical direction. The air members are selectively operably disposed.

[0006]

With the above-mentioned structure, the raw water, which is the liquid to be treated, mixed with the nitrification liquid and supplied into the tank, is subjected to the denitrification treatment in the denitrification zone below the aeration diffuser. The point that the nitrification treatment is performed in the upper nitrification zone is the same as a conventional nitrification denitrification apparatus using this type of biofilm filtration, but the aeration diffuser is arranged vertically in the tank. Since a plurality of diffuser members are provided and one of the diffuser members is selected and operated in accordance with the quality of the raw water, the residence time of the raw water in the nitrification zone and the denitrification zone is optimized and the treatment is efficient. Will be performed.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. In the figure, reference numeral 1 denotes a tank, 2 denotes an aeration diffuser disposed substantially at the center of the tank 1, and 3 and 4 denote nitrification zones and denitrification formed respectively at upper and lower portions of the aeration diffuser 2. Zone. The aeration diffuser 2 is provided with three vertically dispersing members 5, 5 and 5 in the tank 1, and each of the dispersing members 5 adjusts a motor valve 6. , So that it can be selectively operated.

The plurality of air diffusing members 5 are arbitrarily selected and operated in accordance with the quality of the raw water, so that the volume ratio between the nitrification zone 3 and the denitrification zone 4 is changed so that the raw water stays in each zone. This is to optimize the time. Here, assuming that a zone corresponding to the vertical length of the three-stage diffuser member 5 is a common zone 7 for nitrification and denitrification, the allocation of each zone is (nitrification zone + denitrification zone): common zone = 1: 1. ~
About 2: 1 is preferable, and nitrification zone: denitrification zone =
1: 1 is preferred. Therefore, nitrification zone: denitrification zone:
Shared zone = 1: 1: 2 to 1: 1: 1 is standard. Each zone is filled with a carrier. The specific gravity is preferably about 1.2 to 1.4 in the nitrification zone, about 1.8 to 2.0 in the denitrification zone, and about 1.5 to 1.7 in the common zone. This is to prevent the carriers from mixing during backwashing.

The common zone 7 is provided with a plurality of air diffusing members 5, 5, 5 in the vertical direction, which are connected to motor valves 6, 6, 6, respectively, and which are controlled by a control device 8 to control the air flow. And the aeration point can be arbitrarily selected and controlled. Further, a nitrite / nitric acid detector 9 is provided slightly below each diffusing member 5, and an ammonia detector 10 is provided except for the lowermost diffusing member 5. The detector 10 is also provided at the outlet of the nitrification zone 3. The signals from these detectors are configured to be input to the control device 8. At the bottom of the denitrification zone 4, an air supply device 11 and a water supply device 12 for backwashing treatment are provided, and the nitrification zone 3 and the denitrification zone 4 are connected by a nitrate return pipe 13. This is the same as in the prior art.

[0010] In the above-mentioned structure, the nitrification liquid returned from the nitrification zone 3 and the raw water are first mixed and supplied to the denitrification zone 4 at the lower part of the tank 1. Nitric acid is denitrified using BOD in raw water as a hydrogen donor. Next, the nitrogen is aerated in the nitrification zone 3, and the organic nitrogen and the ammonia nitrogen in the raw water are nitrified, a part is discharged as treated water, and the remainder is returned to the denitrification zone 4 again. Here, if the raw water contains a large amount of organic nitrogen and ammonia nitrogen, the treatment in only the nitrification zone 3 is not sufficient for nitrification, and remains in the nitrification liquid. In this case, the amount of air in the air diffusion member 5 at the bottom of the nitrification zone (the uppermost stage of the common zone) is increased by the signal of the ammonia detector 10 at the exit of the nitrification zone 3. If the nitrification is still insufficient, the aeration of the diffuser member 5 in the middle stage of the common zone 7 is also added.
Then, such an additional operation of increasing the air amount and aerating the diffuser member 5 is continued until organic nitrogen and ammonia nitrogen are not detected at the nitrification zone outlet. In addition,
When the amount of organic nitrogen or ammonia nitrogen in the raw water is reduced, the ammonia detector 1 provided at the lower part of each diffuser 5
The above operation may be performed in reverse with a signal of 0.

On the other hand, when the amount of organic nitrogen and ammonia nitrogen in the raw water is small, the residence time in the nitrification zone 3 is prolonged, so that the nitrification is completed.
DO makes denitrification in denitrification zone 4 insufficient. In this case, the reverse operation to the above-mentioned nitrification is performed by the signal of the nitrous acid / nitric acid detector 9 below the air diffusion member. By using the common zone 7 arbitrarily and selectively as a nitrification zone or a denitrification zone according to the quality of raw water, nitrification and denitrification can be performed extremely efficiently.

It should be noted that which of nitrification and denitrification is prioritized in the above operation may be incorporated in the control device 8 in advance. The cycle of nitrification and denitrification treatment → empty washing → water washing and the time distribution thereof are the same as in the conventional method.

Table 1 shows the results of treating the sewage at a scale of 1 m ³ / Hr using the present apparatus and the results of treating the sewage using a conventional apparatus as a comparative example.

[0014]

[Table 1]

As is clear from Table 1, it was confirmed that in the example, the treatment can be performed efficiently with a tank as small as 20% as compared with the conventional method. In addition, about 35 for TN
% Can improve the treatment effect, and the amount of air used is about 20%.
It was confirmed that the percentage could be reduced by as much as%.

[0016]

As is apparent from the above description, the present invention makes it possible to optimize the residence time of raw water in each zone according to the water quality by arbitrarily changing the ratio between the nitrification zone and the denitrification zone. The nitrification and denitrification can be performed as much as possible, and the processing tank can be downsized, so that the entire apparatus can be designed to be compact.
Therefore, the present invention greatly contributes to industrial development as a nitrification and denitrification apparatus by biofilm filtration that has eliminated the conventional problems.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a front view showing a conventional technique.

[Explanation of symbols]

 Reference Signs List 1 tank 2 aeration diffuser 3 nitrification zone 4 denitrification zone 5 diffuser 8 controller 9 nitrite / nitric acid detector 10 ammonia detector

Claims (2)

(57) [Claims] 1. A nitrification denitrification apparatus using biofilm filtration, wherein an aeration diffuser is disposed in a tank, and an upper part of the aeration diffuser is a nitrification zone and a lower part is a denitrification zone. A nitrification denitrification apparatus using biofilm filtration, wherein a plurality of air diffusing members arranged in a vertical direction in a tank are provided in a gas device, and the gas diffusing members are selectively operable. 2. A plurality of ammonia detectors are provided in the vertical direction of the nitrification zone, and a plurality of nitrite / nitric acid detectors are provided in the vertical direction of the denitrification zone. The nitrification denitrification apparatus according to claim 1, wherein a control device for selecting and operating one of the air diffusion members based on a signal from the vessel is connected to the air diffusion air diffusion apparatus.