JPS6247430B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for maintaining the amount of short-wavelength ultraviolet rays irradiated from a low-pressure mercury lamp at a high output in a method for treating waste water with ultraviolet rays using a low-pressure ultraviolet mercury lamp.

Conventional UV irradiation treatment methods for industrial wastewater using ultraviolet mercury lamps include sterilization, deodorization, and treatment of industrial wastewater.
For decolorization or COD treatment, there are known methods in which the water to be treated is irradiated with ultraviolet rays from a low-pressure mercury lamp, or a method in which ultraviolet rays are irradiated with ozone while blowing ozone into the water to be treated.

In the UV irradiation treatment method for wastewater used for these purposes, short wavelength UV rays (mainly germicidal radiation) are more effective than long wavelength UV rays, so mercury lamps emit UV rays with long wavelengths, such as wavelengths of 365 nm or more. It is not a high-pressure or ultra-high-pressure mercury lamp, but a wavelength of 254nm,
Low-pressure mercury lamps are used, which mainly emit ultraviolet light with short wavelengths such as 313 nm.

However, in these low pressure mercury lamps,
As the ambient temperature rises, the internal pressure of the mercury lamp also rises, and what would otherwise be a low-pressure lamp that would emit a lot of short-wavelength ultraviolet rays becomes high-pressure, causing it to emit more long-wavelength ultraviolet rays such as 313 nm and 365 nm.

Furthermore, if the ambient temperature of the mercury lamp is too low, the necessary excitation cannot be obtained inside the mercury lamp, and sufficient ultraviolet light output cannot be obtained.

Therefore, as shown in Figure 1a, a bell-shaped curve can be drawn between the ambient temperature of a mercury lamp and the amount of short-wavelength ultraviolet rays centered on the optimal ambient temperature at which the amount of short-wavelength ultraviolet rays reaches its peak value. .

Many commercially available low-pressure mercury lamps have an optimum ambient temperature of around 30°C.

Furthermore, commercially available low-pressure mercury lamps generally have a protective tube made of quartz or the like covering their outer periphery.

This is to ensure insulation when the mercury lamp is inserted into the water to be treated, and to prevent mercury from getting mixed into the water to be treated due to breakage of the mercury lamp.

However, on the other hand, since the outer circumference of the mercury lamp is protected by a quartz tube, there is a considerable difference between the water temperature of the water to be treated and the ambient temperature of the mercury lamp inside the quartz tube, and even when the water temperature is low, the ambient temperature may already have reached the optimum ambient temperature.

Further, when a protective tube such as a quartz tube is provided around the outer circumference of a mercury lamp, ultraviolet rays are absorbed by the protective tube itself, inevitably reducing the efficiency of ultraviolet irradiation. That is, even if a high-quality quartz tube is used as a protection tube, it will normally absorb about 20% of ultraviolet rays, especially ultraviolet rays in a short wavelength range such as 254 nm, and the amount of ultraviolet rays irradiated to the water to be treated will decrease.

Furthermore, the oxygen in the air between the mercury lamp and the protection tube is converted into ozone by ultraviolet rays, but since ozone absorbs ultraviolet rays in the short wavelength range well, the amount of ultraviolet rays irradiated to the water to be treated is reduced. I end up.

Also, the UV intensity of the mercury lamp, which is the light source, is 2 times the distance.
It is attenuated in inverse proportion to the power of Since the diameter of the treatment tank cannot be made too large, there is not much freedom in the diameter of the protection tube. That is, when the diameter of the protection tube is small, the ventilation effect is reduced, and when it is large, the effective volume of the treatment tank is reduced, and the sterilization processing capacity is reduced.

In view of the above circumstances, the purpose of this invention is to maintain the amount of short-wavelength ultraviolet rays emitted from a low-pressure mercury lamp at a high output in a method of ultraviolet irradiation treatment of industrial wastewater using an ultraviolet low-pressure mercury lamp, and the gist thereof is to The mercury lamp is inserted directly into the water to be treated without installing a protective tube around its outer circumference, and when the temperature is lower than the peak value of the short-wavelength ultraviolet rays of the low-pressure mercury lamp, the water temperature of the water to be treated as detected by the detector is Accordingly, the voltage or amount of current supplied to the low-pressure mercury lamp is controlled to adjust the amount of short-wavelength ultraviolet rays, thereby maintaining the amount of short-wavelength ultraviolet rays at a high output.

In other words, by directly inserting a low-pressure mercury lamp into the water to be treated without providing a protective tube around its outer circumference, the ambient temperature of the low-pressure mercury lamp will not become abnormally high even though the water temperature is low; Since the mercury lamp is not saturated at temperatures lower than the peak value of the short-wavelength ultraviolet rays of the mercury lamp, it is possible to control the voltage or current amount supplied to the low-pressure mercury lamp according to the temperature of the water to be treated detected by the detector. Since the amount of short-wavelength ultraviolet rays can be increased to compensate for the weight loss in the low-temperature region, the amount of short-wavelength ultraviolet rays can be maintained at a high output (Fig. 1b).

The present invention will be explained below based on the illustrated embodiments. Fig. 2 shows an embodiment in which the present invention is applied to an ultraviolet irradiation treatment method using ozone, and 1 indicates a treatment tank. The water to be treated is fed into the tank from an inlet 1a provided at the lower end, and is discharged to the outside from an outlet 1b provided at the upper end.

A low-pressure mercury lamp 2 is inserted into the treatment tank 1 without an external protection tube, and a diffuser plate 4 connected to an ozone supply pipe 3 is provided below the low-pressure mercury lamp 2.

Ozone is supplied from an ozone generator or the like installed externally through the ozone supply pipe 3, and this ozone becomes bubbles from the air diffuser plate 4 and is sent into the treatment tank 1. UV rays are irradiated. A part of the irradiated ultraviolet rays activates the ozone bubbles sent into the treatment tank 1, and purification treatment such as sterilization, deodorization, decolorization, or COD removal of the water to be treated is effectively performed.

A temperature detector 5 is provided in the processing tank 1 configured as described above, and this temperature detector 5 is connected to a temperature detection unit 6 provided outside. The temperature inside the lamp 1 is converted into a control signal by the temperature detection unit 6, and this control signal is applied to the dimmer 7 provided in conjunction with the low-pressure mercury lamp 2. The dimmer 7 supplies the above control signal to the low-pressure mercury lamp 2. The voltage or current is controlled and applied to the lighting device 8 of the low-pressure mercury lamp 2.

In the treatment apparatus configured as described above, the water to be treated is fed into the treatment tank 1 at a water temperature of about 10 to 40°C.

On the other hand, the low-pressure mercury lamp 2 inserted into the treatment tank 1 sets its optimum temperature to the upper limit of the temperature change range of the water to be treated, for example, 40
Set close to ℃. However, it is generally preferable to set the optimum temperature for operation of a low-pressure mercury lamp in the range of 20 to 30°C, so in this case, the temperature of the water to be treated is adjusted to keep the upper limit to 20 to 30°C.

In addition, in this invention, the low-pressure mercury lamp 2 is directly inserted into the water to be treated without providing an external protective tube such as a quartz tube, so the water temperature and the low-pressure mercury lamp 2 are
There is almost no difference between the ambient temperature of .

On the other hand, if the water temperature is lower than the optimum operating temperature of the low-pressure mercury lamp, this water temperature is detected by the temperature detector 5, and the control signal obtained from this controls the dimmer 7 to adjust the voltage supplied to the low-pressure mercury lamp 2. Increase the current and apply it to the lighting device 8.

In addition, in this invention, the optimum temperature of the low-pressure mercury lamp is set as close as possible to the upper limit of the water temperature variation range of the water to be treated, so that on the lower side of the optimum temperature, the mercury lamp is in an unsaturated state, and the mercury lamp is supplied to the mercury lamp. When the amount of voltage or current is increased, the amount of short-wavelength ultraviolet rays irradiated from the low-pressure mercury lamp can be increased in proportion.

Therefore, as mentioned above, when the temperature is lower than the optimum temperature of the low-pressure mercury lamp, if the voltage or current amount is increased and applied to the lighting device 8 to compensate for the reduction in the amount of short-wavelength ultraviolet rays, the short-wavelength It is possible to irradiate an amount of short wavelength ultraviolet rays comparable to the peak value of the amount of wavelength ultraviolet rays.

Therefore, in the present invention, the amount of short-wavelength ultraviolet rays can be maintained at a high output over the entire temperature change range of the water to be treated, and effective purification treatment can be performed.

In addition, in this invention, two mercury lamps are placed in the water to be treated.
Since the mercury lamp 2 is directly inserted into the water to be treated without providing a protective tube around its outer periphery, the surface of the mercury lamp 2 is constantly cooled by the water to be treated, and the operation of the low-pressure mercury lamp 2 can be stabilized.

Furthermore, unlike conventional mercury lamps, the ultraviolet rays emitted from the mercury lamp are not absorbed by protective tubes such as quartz tubes, and the ozone generated between the mercury lamp and the protective tube absorbs ultraviolet rays in the short wavelength range. Nor.

Therefore, in the mercury lamp used in this invention, high-power ultraviolet rays could be continuously irradiated for a long period of time. On the other hand, mercury lamps that are surrounded by a quartz tube with one end open (open jacket type) and mercury lamps that are surrounded by a blind quartz tube (sealed jacket type) cannot continue to irradiate high-power ultraviolet rays for a long time. I couldn't do it (see Figure 3).

In the present invention, the mercury lamp is directly inserted into the water to be treated without providing a protective tube around its outer periphery, and FIG. 4 shows the mercury lamp used for this purpose.

According to FIG. 4, both ends of the U-shaped mercury-filled tube 9 filled with inert gas such as mercury and argon form base tube portions 9a, 9a having a relatively small diameter.
Electrode parts 9b, 9b are provided at the tips of a, 9a, and lead wires connected to a light control device 7 provided outside are drawn out from the electrode parts 9b, 9b.

Reference numerals 10 and 10 denote joint tubes having approximately the same diameter as the mercury-filled tube 9, and the base tube portion 9a of the mercury-filled tube 9 is provided with electrode portions 9b, 9b at the ends of the foot tubes 10, 10 as described above. , 9a are inserted, and further the joint pipes 10, 10 are inserted.
The inside of the joint tube 1 is filled with a sealing material 11 such as a non-hardening synthetic resin, such as a silicone-based synthetic resin, so as to embed the base tube portions 9a and 9a and the electrode portions 9b and 9b.
0 and 10 and the mercury-filled tube 9 are connected.

Further, a disk-shaped plate plate 12 is provided at the upper end of the joint tubes 10, 10, and a dish member 1 having a downward protrusion 13a at the center of the bottom of the mercury-filled tube 9 is provided below the mercury-filled tube 9.
3 and a support plate 14 having an opening 14a is provided.

The dish member 13 has a lower protrusion 13a with an opening 14a.
By inserting the mercury-filled tube 9 into the support member 14, the dish member 13 receives the lower end of the mercury-filled tube 9 with a cushion packing 15 interposed therebetween.

On the other hand, the plate plate 12 and the plate member 13 to the support plate 1
A plurality of holding rods 16, .

Further, the retaining rods 16, .
0,10 and the mercury-sealed tube 9 are held between the support members consisting of the plate plate 12 and the dish member 13 to the support plate 14 using the nuts 18,...
..., the plate plate 12 and the dish member 13 to the support plate 14
Fixed to.

In order to maintain airtightness inside the joint pipes 10, 10, in this embodiment, an upper cover 19a is provided at the upper end of the plate plate 12, and a lower cover 19a is provided at the lower end of the plate plate 12 via a gland packing 20. 1
9b is provided. Further, 21 is a guide rod for assembling the device.

The low-pressure mercury lamp configured as described above is directly inserted into the treatment tank 1 without providing a protective tube around its outer periphery, but according to this embodiment, the low-pressure mercury lamp has a mercury-filled tube 9 in a U-shape. At the same time, both ends of the mercury-filled tube 9 are inserted into the connecting tubes 10, 10, and a non-curing synthetic resin sealing material is applied to the inserted portion. Since both tubes are connected by filling
It has high mechanical strength and is resistant to external shocks.
Further, external shocks are absorbed by the sealing material 11.

Therefore, according to this embodiment, even if the low-pressure mercury lamp is inserted into the treatment tank 1, there is no risk that the mercury lamp will be damaged in the treatment tank 1, and the water to be treated can be irradiated with ultraviolet rays extremely safely. At the same time, since the electrode parts 9b and 9b are covered with an insulating sealing material such as silicone-based synthetic resin, there is no risk of electrical leakage even if they are inserted into the water to be treated. Ideal for

[Brief explanation of the drawing]

Figure 1 compares the relationship between changes in ambient temperature and short-wavelength ultraviolet light intensity reduction rate in low-pressure mercury lamps according to the conventional method and the present invention. The relationship curve between the amount of ultraviolet rays in FIG. A diagram showing the relationship between usage time and ultraviolet intensity in the mercury lamp used in the invention, comparing a conventional open jacket type and a round sealed jacket type,
FIG. 4 shows a mercury lamp used in the present invention, with FIG. 4a being a side view and FIG. 4b being a longitudinal sectional view of the same. In the figure, 1 is a treatment tank, 2 is a low-pressure mercury lamp, 5 is a temperature detector, 6 is a temperature detection unit, 7 is a light control device,
8 is a lighting device, 9 is a mercury-filled tube, 10, 10 are joint tubes, 11 is a sealing material, 16, . . . are holding rods.

Claims (1)

[Claims] 1. In the ultraviolet irradiation treatment method for industrial wastewater using a low-pressure mercury lamp, the low-pressure mercury lamp is directly inserted into the water to be treated without providing a protective tube around its periphery, and the temperature is lower than the peak value of the short wavelength ultraviolet rays of the above-mentioned low-pressure mercury lamp. On the side, the amount of short wavelength ultraviolet rays is adjusted by controlling the voltage or amount of current supplied to the low pressure mercury lamp according to the temperature of the water to be treated detected by a detector. Method for maintaining high output of ultraviolet low-pressure mercury lamp during irradiation treatment.