JPH091167A - High-degree water purification system - Google Patents

Abstract

PURPOSE: To prevent the dissolved ozone included in water to be treated subjected to a treatment in an ozone contact vessel from adversely affecting the treatment in a biologically active carbon column. CONSTITUTION: The high-degree water purification system including the ozone contact vessel 1 and the biologically active carbon column 2 is provided with an aeration tank 6 having an air diffusion pipe 8 behind the ozone contact vessel and before the biologically active carbon column and is provided with an aeration air quantity controller 20 for controlling the quantity of the air to be sent into the air diffusion pipe 8 in accordance with the dissolved ozone concn. of the water to be treated in the lower bottom of the air diffusion pipe installed in the aeration tank. As a result, the dissolved ozone remaining after the ozone treatment is prevented from adversely affecting the treatment in the biologically active carbon treatment column.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly purified water treatment system provided with an ozone contact tank and a biological activated carbon tower, and in particular, dissolved ozone contained in water to be treated in the ozone contact tank is used in the biological activated carbon tower. The present invention relates to an advanced water purification system that does not adversely affect the treatment.

[0002]

2. Description of the Related Art Due to industrial development or population concentration in cities, various kinds of drainage have come into public water bodies, and water pollution of rivers and lakes, which are the sources of tap water, is progressing.

Conventionally, in a water purification system, a combination of coagulation sedimentation treatment, sand filtration treatment, chlorine treatment, etc.
The turbidity components in the water to be treated have been removed and sterilization has been performed.

However, as the water source becomes polluted with water, odorants, trihalomethane precursors, ammoniacal nitrogen, etc. are added, and the combination of the conventional coagulating sedimentation treatment, sand filtration treatment, and chlorine treatment causes a color and an offensive odor. There are limits to taste removal and organic material removal.

From the above, attention has been paid to an advanced water treatment system in which an ozone contact tank and a biological activated carbon tower are added to the conventional water treatment system. An example of such an advanced water purification system is described in Japanese Patent Laid-Open No. 5-245484.

[0006]

According to an advanced water purification treatment system equipped with an ozone contact tank and a biological activated carbon tower,
The off-flavor and organic substances can be removed by oxidative decomposition.

However, the water to be treated which has been subjected to the ozone treatment in the ozone contact tank contains dissolved ozone, which adversely affects the treatment in the biological activated carbon treatment tower in the next stage. Japanese Patent Laid-Open No. 5-245484 does not address such a problem.

Therefore, an object of the present invention is to provide a highly purified water treatment system in which the dissolved ozone contained in the water to be treated treated in the ozone contact tank does not adversely affect the treatment in the biological activated carbon tower. .

[0009]

The present invention provides an advanced water purification system for treating water to be treated, which comprises an ozone contact tank and a biological activated carbon tower, and is provided in a stage after the ozone contact tank and before the biological activated carbon tower. An aeration tank provided with an air diffuser, and aeration for controlling the amount of air sent to the air diffuser based on the concentration of dissolved ozone in the water to be treated at the bottom of the air diffuser installed in the aeration tank It is an advanced water purification system characterized by having an air volume control means.

In order to detect the dissolved ozone concentration of the water to be treated at the lower bottom of the air diffuser installed in the aeration tank, the dissolved ozone concentration is further lower than the installation position of the air diffuser installed in the aeration tank. It is desirable to install a measuring instrument.

Further, the ozone contact tank is composed of a plurality of reaction chambers, the gas phase portion of each reaction chamber is separated by each wall, and the liquid phase portion of each reaction chamber causes the treated water that has overflowed to react from one to the other. It is desirable that the reaction chambers or adjacent reaction chambers flow into each other, and that each reaction chamber is provided with an ozone diffusion pipe.

Even if an aeration tank is installed after the ozone contact tank, the dissolved ozone cannot be effectively removed if the aeration air volume is kept constant and supplied regardless of the dissolved ozone concentration. In addition, it may result in wasted air volume and cost.

According to the present invention, it is possible to supply an appropriate amount of air corresponding to the dissolved ozone concentration, and it is possible to effectively remove the dissolved ozone.

[0014]

[Function] After the ozone contact tank, before the biological activated carbon tower,
By providing an aeration tank having an air diffuser to diffuse air, ozone is discharged into the gas phase from the ozone-treated water to be treated, and when the water to be treated enters the biological activated carbon tower,
Dissolved ozone can be removed without adversely affecting the treatment in the bioactivated carbon tower.

By detecting the dissolved ozone concentration contained in the water to be treated during the aeration treatment and controlling the amount of aeration air based on the detected concentration, the dissolved ozone concentration in the treated water adversely affects the treatment in the biological activated carbon tower. It is possible to effectively remove even the area that does not exist.

The air jetted by the air diffuser in the aeration tank rises in the liquid phase toward the water surface and, in the process, discharges ozone into the gas phase. Therefore, in order to detect the true ozone concentration in the water to be treated, it is necessary to sample the water to be treated from a position below the air diffuser and measure the ozone concentration. By installing an ozone concentration measuring device further below the position where the air diffuser in the aeration tank is installed, measuring the ozone concentration there, and controlling the air volume supplied to the air diffuser based on this, It can effectively remove ozone and discharge it into the gas phase. In addition, it is possible to prevent excess and deficiency of the air volume.

[0017]

Embodiments of the advanced water purification system of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration diagram of an advanced water purification treatment system including an ozone contact tank and a biological activated carbon tower. In this embodiment, the ozone contact tank 1
Is composed of three reaction chambers 14a, 14b, 14c. An aeration tank 6 having an air diffuser 8 is provided adjacent to the reaction chamber 14c at the final stage. The reaction chambers 14a, 14b, 14c have ozone diffusing tubes 3 respectively.
a, 3b, 3c are installed. These ozone diffusers are connected to the ozonizer 5.

The water to be treated which has been subjected to the coagulation sedimentation treatment and the sand filtration treatment in the water purification plant is sequentially supplied to the reaction chambers 14a, 14b and 14c of the ozone contact tank 1 as shown by arrows. First, the water to be treated is introduced into the reaction chamber 14 a and treated with ozone ejected from the ozone diffusing pipe 3. Then, it is introduced into the reaction chamber 14b and the reaction chamber 14c and subjected to ozone treatment. Ozone injected into the water to be treated by the ozone diffuser is absorbed in the liquid phase to oxidize the water to be treated. As a result, the off-flavor, color, etc. in the water to be treated are removed, and the organic substances are decomposed.

The water to be treated in which ozone has been diffused is then introduced into the aeration tank 6. In the aeration tank 6, the ozone treatment of the water to be treated continues to proceed, but the aim here is to eject air by the air diffuser 8 to discharge the dissolved ozone into the gas phase. For this purpose, it is necessary to accurately measure the ozone concentration in the liquid phase. In this embodiment, the ozone concentration measuring instrument 9 is installed in the liquid phase to measure the ozone concentration. . Alternatively, the water to be treated may be sampled to measure the ozone concentration. When the ozone concentration is measured, this signal is sent to the aeration air volume control device 20 to control the air volume of the air blown by the air diffuser 8.

In order to measure the true ozone concentration contained in the water to be treated in the aeration tank 6, the ozone concentration measuring instrument 9 should be installed further below the position where the air diffuser 8 is installed. is there.

In the reaction chambers 14a, 14b, 14c,
The ozone discharged into the gas phase without being absorbed into the liquid phase and the ozone discharged into the gas phase in the aeration tank 6 are sent to the waste ozone treatment tower 4 containing the ozone decomposition catalyst, and are harmless gas. After being decomposed into air, it is released into the atmosphere by the blower 15.
The exhaust ozone treatment tower 4 may treat ozone by thermal decomposition, soil decomposition, chemical cleaning or activated carbon treatment, instead of decomposing ozone by a catalyst. When performing the exhaust ozone removal processing in the exhaust ozone processing tower 4, it is desirable to provide an ozone concentration measuring device 7 to measure the concentration of the exhaust ozone.

FIG. 2 shows a block diagram of an aeration air volume control device 20 for controlling the air volume of the air supplied to the air diffuser 8. The signal obtained by the ozone concentration measuring device 9 in the aeration tank 6 is transmitted to the air volume control controller 13. In the air volume control controller 13, based on the ozone concentration, the set value of air (SV value), and the value detected by the air volume meter 12 of the aeration blower 10, the air volume valve adjusting motor attached to the aeration blower 10 is installed. The rotation speed of 11 is adjusted to control the air volume of the air blown from the aeration blower 10. Aeration tank 6
The water to be treated, which has been subjected to the removal treatment of dissolved ozone in 1., is introduced into the biological activated carbon tower 2 in the next stage and treated. In this example,
Two biological activated carbon towers are provided and the other biological activated carbon tower is operated while the other is activated by back washing or the like. However, the number of biological activated carbon towers does not have to be two.

Since the treated water is subjected to the dissolved ozone removal treatment before being introduced into the biological activated carbon tower, even if biological activated carbon to which bacteria such as nitrifying bacteria are attached is used as activated carbon, it will be destroyed. Nonetheless, treatment with biological activated carbon can be effectively performed. By this biological activated carbon treatment, ammonia and biodegradable substances that cannot be removed by the usual activated carbon treatment can be removed, and high-quality treated water can be supplied to consumers. In addition, since the dissolved ozone removal treatment is performed before being introduced into the biological activated carbon tower, there is an effect that the biological activated carbon treatment time can be shortened.

[0024]

INDUSTRIAL APPLICABILITY According to the present invention, in an advanced water purification treatment system equipped with an ozone contact tank and a biological activated carbon tower, dissolved ozone contained in the water to be treated treated in the ozone contact tank can be treated in the biological activated carbon processing tower. It was possible to prevent adverse effects.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an advanced water purification treatment system showing an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an aeration air volume control device in the advanced water purification treatment system of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ozone contact tank, 2 ... Biological activated carbon tower, 5 ... Ozonizer, 6 ... Aeration tank, 8 ... Air diffuser, 9 ... Ozone concentration measuring device, 14a, 14b, 14c ... Reaction chamber, 20 ... Aeration air volume control device.

Claims (3)

[Claims] 1. A highly purified water treatment system comprising an ozone contact tank and a biological activated carbon tower for treating water to be treated, wherein aeration is provided with an air diffuser pipe after the ozone contact tank and before the biological activated carbon tower. A tank is provided, and aeration air volume control means for controlling the air volume of the air sent to the air diffusion tube based on the dissolved ozone concentration of the water to be treated at the lower bottom of the air diffusion tube installed in the aeration tank is provided. A featured advanced water purification system. 2. The highly purified water treatment system according to claim 1, wherein a dissolved ozone concentration measuring device is installed at a bottom portion below the air diffuser installed in the aeration tank. 3. The ozone contact tank according to claim 1 or 2, wherein the ozone contact tank is composed of a plurality of reaction chambers, the gas phase portion of each reaction chamber is separated by each wall, and the liquid phase portion of each reaction chamber overflows. An advanced water purification system characterized in that the treated water is configured to flow from one reaction chamber to the other reaction chamber or an adjacent reaction chamber, and an ozone diffusion pipe is provided in each reaction chamber.