JP2001232358A - Metazoa removal process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water treatment process which enables stable removal of metazoa without forming any undesirable byproduct such as chlorinated organic compound in a chlorine disinfection process or concentrate in a membrane filtration process, and further, without any restriction with respect to the volume of water to be treated. SOLUTION: This metazoa removal process comprises passing an object to be treated, i.e., water to be treated which contains metazoans, through a UV irradiation treatment device and a sand filtration treatment device in that order. In the UV irradiation treatment, UV of 200-300 nm wavelengths are used and the total disinfectant UV output is adjusted to a value within a range less than the required dose for disinfecting 90% of the target metazoa, which value is expressed in terms of the treatment UV dose applied to the volume of water to be treated, to suppress mobility of the metazoa, and thereafter subjecting the resulting treated water to sand filtration treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing metazoans in water treatment of tap water and water using river water or the like as a water source.

[0002]

2. Description of the Related Art In a water treatment process using river water or the like as a water source, metazoans such as nematodes and rotifers are often contained in raw water of intake water, and conventionally, treatment with an oxidizing disinfectant such as chlorine is used. , As well as by coagulation sedimentation and filtration. However, in metazoans, chlorine tolerance is high,
In addition, there is an object having mobility, and these processes cannot completely remove them, and that process is a problem. Also,
When the activated carbon treatment is included in the water treatment system, bacteria that live in the activated carbon layer are eaten, metazoans proliferate, and may leak to the final treated water.

[0003] As a method for removing these metazoans, the above-mentioned disinfection treatment using an oxidizing agent-based disinfectant, coagulation treatment using a flocculant, removal treatment by filtration, and removal treatment by a membrane filtration method using an MF membrane or the like are mentioned. Are known. But,
In the case of oxidizing disinfection, when the concentration of the disinfectant is increased, chlorine compounds such as trihalomethane and chlorine are used. The inconvenience was not escaped. In addition, the processing in the final step has a disadvantage of being restricted for the same reason. In the coagulation sedimentation treatment with PAC (polyaluminum chloride) and the like, the removal rate remains in the 90% range as long as the metazoan motility is not completely stopped. Together, maintaining perfectly stable removal performance is a difficult situation. The membrane filtration method using an MF membrane, etc.
It is limited to the case where the amount of treated water is relatively small. Some metazoan animals with high mobility pass through the membrane of a pleated MF filter, so that it is necessary to use some sort of disinfection.

[0004]

In the prior art treatment with a disinfectant, some by-products are formed, and the coagulation sedimentation treatment or the filtration treatment or membrane filtration alone does not stop the metazoan motility unless it stops. It is difficult to obtain effective removal performance. In addition, in the case of a membrane treatment which can obtain a relatively high removal rate, it cannot be said that the technology and cost are still sufficient when the amount of water is large. The present invention provides a water treatment method capable of stably removing metazoans without forming by-products while addressing the various problems described above, and furthermore, is not restricted by the amount of water. is there.

[0005]

In order to solve the above-mentioned problems remaining in the conventional processing technology, the present inventors have developed a method for removing metazoans with high safety and high removal performance. After intensive research on possible methods, the most practical method is to remove the metazoans that enter by removing the minimum necessary amount of ultraviolet light and then passing the water through a sand filtration facility equipped with surface washing and backwashing equipment. And it came to know that it was effective. That is, the present invention is a water treatment process using river water or the like as a water source, a method for removing metazoans contained in raw water or each step water by ultraviolet treatment, and then removing the treated animals by sand filtration. The feature of the present invention is that in order to stabilize the motility and growth ability of metazoans contained in the raw water of the water treatment process and the process water, the metazoans in the stationary state are irradiated with a minimum amount of ultraviolet irradiation, The purpose is to ensure that it is captured by sand filtration.

[0006] Next, by setting the reversal frequency of sand filtration with backwash water, which has sufficiently killed metazoans, at least once per day, the captured metazoans are reactivated, motility and multiplication are achieved. Before discharging to the outside together with the backwash water. Further, metazoans in the backwash water are treated with ultraviolet rays and a disinfectant, and then discharged out of the system or collected in a step before each disinfecting means. By treating in this way, metazoans contained in a large-scale water volume are concentrated in the backwash wastewater, and then effectively killed. The removal of metazoans can be achieved.

That is, the present invention comprises the following items. (1) Metazoa, which is composed of a combination of an ultraviolet irradiation treatment and a sand filtration treatment, and wherein water to be treated containing metazoa to be treated is passed in the order of an ultraviolet irradiation treatment and a sand filtration treatment. Removal method. (2) The ultraviolet irradiation treatment in the former stage is performed at an emission wavelength of 200 to 30.
0 nm light is output continuously or intermittently, and the total germicidal UV output at a wavelength of 200 to 300 nm is within the required dose of 90% sterilization of the target metazoan in terms of the amount of treated UV with respect to the amount of treated water, The method for removing metazoan animals according to the above (1), wherein motility of metazoans is suppressed.

[0008] (3) The sand filtration treatment in the latter stage has the functions of washing the surface and backwashing the water in the support layer, and washing the air with the backwashing water. The method for removing metazoan animals according to the above (1), wherein each treated water of the agent is used, and the frequency of the backwash is at least once a day. (4) The backwash wastewater discharged from the subsequent sand filtration treatment is treated with a sterilizing means using ultraviolet rays, ozone or a chlorine-based oxidant-based disinfectant, and then discharged outside the system or collected in a preceding process of each disinfecting means. The method for removing metazoan animals according to the above (1), wherein (5) A metazoan animal which is constituted by a combination of an ultraviolet irradiation device and a sand filtration device, and wherein the treated water containing metazoa to be treated is passed through the ultraviolet irradiation device and the sand filtration device in this order. Removal device.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on each processing step. The water to be treated including metazoans to be removed is first transiently passed through an ultraviolet irradiation device,
A minimum required amount of ultraviolet rays in a wavelength range necessary to suppress the motility of the metazoan in the target water is irradiated to stop the motility of the metazoan. The wavelength range of light required here is 200
To 300 nm, preferably a wavelength around 250 ± 10 nm as a main wavelength, and desirably contains 30% or more as a relative intensity. The ultraviolet irradiation device used here may be a light source having an ability to emit ultraviolet rays in a wavelength range of 200 to 300 nm continuously or intermittently in a pulsed manner. As a method of the light emitting source, any of a mercury lamp method, a xenon lamp method, a laser type arc discharge method and the like can be used. However, a mercury lamp method is practical and desirable for treating a large amount of treated water at low cost.

In the following description, the present invention will be described using a mercury lamp system, but the light emitting source of the present invention is not limited thereto. The types of mercury lamp systems include low-pressure lamps and medium-pressure lamps used for conventional sterilization applications.
Emits a wavelength of 00 to 300 nm, and
What is necessary is just to include a wavelength of 10 nm as a relative intensity of 30% or more. In a device for performing a transient ultraviolet treatment, in the case of a rod-shaped lamp, the water to be treated is processed by flowing the water parallel or perpendicular to the longitudinal direction of the lamp. Any material can be used as long as it can be irradiated uniformly.

[0011] With these ultraviolet irradiation devices, the amount of irradiation to be applied to the target metazoan reduces the required amount of 90% sterilization used as conventional sterilization means, that is, the number of living target organisms to 1/10, The irradiation dose is 90% or less, which is less than the irradiation dose necessary to cause lethality, and a width is generated depending on the wavelength characteristics of the light emitting source. However, preferably, the irradiation amount is 1/2 to 3/4 of the conventional 90% sterilization required dose. . The present inventors have discovered that at this dose, the metazoan of interest can be brought into a stationary state, which has temporarily lost its motility.
In addition, the present inventors assume that the low-pressure lamp having a main wavelength of 254 nm of 90% or more is 照射 of the irradiation dose required for 90% sterilization, contains a wavelength range of 250 ± 10 nm of 30% or more, and 200 to 240 nm, 260-300 nm
In the case of a medium-pressure lamp containing near- and far-ultraviolet rays, the target metazoan enters a quiescent state in which motility has been stopped for more than 24 hours by adding an irradiation dose of 1/2 of the required dose. , A phenomenon in which motility was restored after more than 24 hours was discovered.

This tendency is different from the conventional ultraviolet sterilization mechanism. The conventional theory of the sterilization mechanism targets prokaryotic microorganisms such as bacteria, viruses, and molds. It is explained that the mechanism is that DNA and RNA in the cell nucleus, which are the source of life activity of the organism, absorb 254 nm ultraviolet rays specifically and inhibit the replication function of DNA and RNA, resulting in death of the organism. . However, in eukaryotes that have evolved, such as metazoans, the cell tissue is differentiated, and the irradiation dose required for lethality is generally higher than that of prokaryotic cells, and the damage mechanism by ultraviolet rays,
Its resilience also tends to be different from prokaryotes,
It is easy to imagine.

[0013] Regarding the difference in the effect due to the wavelength characteristics, it is known that the wider the wavelength range in prokaryotes, the more it is absorbed by various biological components and causes multiple obstacles. Incidentally, when ultraviolet light is applied in the presence of oxygen, it is considered that the damage site is triggered by the radical generation due to oxidation of fatty acids of cell membrane lipids, particularly unsaturated fatty acids. It is probable that the medium pressure lamp with a wide wavelength range caused a complex obstacle, so that the irradiation dose required to suppress the motility of metazoans was reduced. In addition, the range of the irradiation dose is the lower limit of the dose at which metabolic animals to be treated begin to cause lethality. When the light source is a low-pressure lamp, the required dose is 3/4 or less of the 90% sterilization required amount. In the case of a medium-pressure lamp, the upper limit is set to 1/2 or less. The upper limit is that the metazoans to be contained in the treated water subjected to the ultraviolet treatment are all over 24 hours,
It is a value obtained on condition that there is no recovery of motility.

As described above, 1/90 of the required dose for 90% sterilization.
After the motility is suppressed by irradiating 2/3/4 of the animals, the live animals are removed by sand filtration in the next step. It is known that metazoans can easily move in the sand filtration layer when they have motility, and it is known that they mix into the treated water side and leak out. In this case, it is an essential processing condition to suppress the motility and keep a stationary state by irradiating ultraviolet rays. The sand filtration equipment used for the above-mentioned sand filtration processing is a downflow type rapid filtration ground used in general water supply treatment and the like, and any sand filtration equipment having a backwashing equipment may be used. As the basic specifications of the equipment, the filtration speed is within 120 to 150 m / d, and hydraulically, any of a gravity type and a pressure type may be used.

The quality of the filtered sand conforms to the standards of the Japan Water Works Association, and the thickness of the sand layer is desirably 60 to 70 cm as a standard. Further, it is preferable that the backwash facility has both functions of surface cleaning for cleaning the surface portion of the sand layer and backflow cleaning from the lower part of the filter layer. When the amount of suspended solids in the filter layer is large, backwashing and air washing may be used in combination. The surface cleaning device used here may be either a fixed type or a rotary type, and the conditions such as the cleaning pressure may be any conditions as long as the muddy layer on the surface is crushed by the shear force of the water flow to improve the cleaning effect. Backwashing also keeps a sufficient washing flow rate and uniform water flow distribution to separate the detained substances in the filter layer from the filter medium, separate the separated substances from the filter layer and discharge them from the trough. Any condition can be used as long as the expansion coefficient of the layer to be effective can be maintained at 20 to 30%.

In the present invention, the condition to be strictly adhered to is the frequency of surface washing and backwashing, and this frequency is determined by the above-mentioned irradiation of ultraviolet light, after which the living animal is reactivated and the motility is reduced. It is determined by the time required to recover, and when the above ultraviolet irradiation dose is added, the frequency of 24 hours, once a day or more is essential, and the trapping efficiency in the filtration layer, the amount of water used in backwashing, etc. Considering this, once / day is appropriate and preferable. Also, water used for the backwashing, the sand filtration process water of the present invention with a minimum of water, as much as possible, it is desirable to use water that kill metazoan, further ^10-4 to sand filtration treatment water It is more preferable to use water that has been subjected to a level of ultraviolet irradiation or disinfected with an oxidizing agent such as ozone. In the case of ozone treatment, ozone water may remain in the filter layer after the backwash operation, and the water may come out as treated water. After confirming that it is necessary to collect water. Considering both of the above treatments of the water used for backwashing, ultraviolet treatment is most practical in terms of the amount of water used, the time required for backwashing, and the like.

As described above, the number of metazoans to be treated in the backwash water is desirably at a level of 1 / m ³ or less. It is desirable that the number of metazoans in the sand-filtered water, which is the backwashing water of the present invention, is at a level of 1 / liter or less. Assuming that metazoans are 1 / m in backwash water
^{When three} or more existing waters are used, metazoans grow on the lower side of the sand filtration layer, easily flow into the treated water, and apparently have a markedly reduced removal performance. Next, if the backwash wastewater containing metazoans separated from the sand filter layer is drained as it is, there is a possibility that a large amount of metazoans will be reactivated at the drainage destination and cause problems such as contaminating the drainage system, After disinfecting to a safe level,
It is desirable to discharge them to the outside of the system, or to collect them in a preceding treatment step before returning to a step capable of removing or disinfecting metazoans.

When the wastewater is disinfected and discharged, the disinfecting means firstly includes a treatment with an oxidizing disinfectant. Examples of the disinfectant used for this purpose include an inorganic chlorine-based disinfectant such as chlorine dioxide, and ozone disinfection for shortening the processing time. In the case of a disinfectant, its lethal effect is mainly determined by the concentration of the disinfectant and the processing time.
It is necessary to provide a contact tank or the like and perform a treatment capable of obtaining a disinfection effect of a level of 10 ^-6 to 10 ^-7 . However, Rhabditis sp., Prec, which is said to be most resistant to oxidizing disinfectants
When treating nematodes such as tus sp. with ozone, 10 ^-6 to 1
To achieve ^0-7 level of inactivation, the CT value (m
g-min / liter) 30-35 mg · min
Per liter of processing.

When UV is used, it is calculated to be 10 ^-6 to 1 based on the required dose of 90% sterilization of the metazoan to be treated.
0 ^-7 seek inert required dose, and the external circulation type ultraviolet irradiation apparatus provided transiently or residence tank, may be added to the process in accordance with the required dose. The backwash wastewater to which the ultraviolet irradiation treatment has been added may be discharged to the outside of the system as it is, or may be returned to the previous stage such as coagulation sedimentation and coagulation filtration capable of removing turbidity and metacarp dead in the backwash wastewater. . When an ozone or chlorine-based oxidant-based disinfectant is used, the backwash wastewater is either neutralized or removed from the remaining disinfectant and then discharged out of the system, or the SS component is removed in the same manner as ultraviolet rays. You may collect | recover by returning to the former stage of the process which can be removed. In addition, when the backwash wastewater is collected once without disinfection, a process capable of disinfecting the metazoan of interest, preferably a coagulation sedimentation, a filtration process, and a disinfection process such as ozone treatment in the subsequent stage, It is desirable to return to the stage before aggregation.

As described above in detail, in the present invention, from the water to be treated including metazoans, in particular, a large amount of water, unnecessary energy is supplied by ultraviolet treatment and sand filtration treatment. The target metazoan is removed and concentrated, and the metazoan concentrated in the backwash wastewater is efficiently and safely inactivated and discharged or collected out of the system. It is possible to remove metazoans with high efficiency and safely.

[0021]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

Embodiment FIG. 1 shows an example of a processing system for carrying out the present invention, and describes a case where processing is performed in a continuous format. River water is used as the raw water 1. In the process of supplying the raw water 1 to the contact pond 2 at a flow rate of 550 m ³ / d, chlorine dioxide (ClO ₂ ) 3 is used.
Is added, and a catalytic oxidation treatment is performed with a residence time of 60 minutes. Then, 75 to 115 mg / liter of a coagulant (PAC) 5 is added to the treated water 4 which has been subjected to the catalytic oxidation treatment, and the coagulant (PAC) 5 is transferred to the coagulation sedimentation basin 6. Treated water 7 from which sediment is separated by coagulation sedimentation
Is then transferred to the ozone contact pond 8 to a concentration of 1.5 to
Ozone treatment is performed at 2.0 mg / liter for a contact time of 12 minutes. The treated water 9 that has undergone the ozone treatment is converted into an activated carbon contact pond 10.
At a water flow rate SV = 5 h ^-1 to obtain target water 11 containing nematodes.

Next, the target water 11 is converted into a medium pressure UV lamp type ultraviolet irradiation device 12 → sand filtration pond 13 according to the present invention.
a → treatment water tank 15a → backwash pump 16a → ultraviolet irradiation device 17 → test zone (A) line leading to sand filtration pond 13a
Sand filtration pond 13b → treated water tank 15b → backwash pump 16b →
Each of the test section (B) lines leading to the sand filtration reservoir 13b has 2
Water was passed at 20 m ³ / day, and the effect of the present invention was confirmed. The filtration speed of the sand filtration ponds 13a and 13b is LV = 100.
m / day, backwashing used both surface washing and backwashing, and the frequency of backwashing was every 24 hours.

The amount of ultraviolet irradiation by the ultraviolet irradiation device 12 is 34 mJ / cm, which is 量 of 90 m sterilization required dose 68 mJ / cm ² of nematodes which are metazoans of interest.
^{And 2} . The backwash water of the sand filtration pond 13a at the final stage is the treated water 14a of the sand filtration pond 13a and the treated water storage tank 15a.
a, Water 17a treated by an ultraviolet irradiation device 17 through a backwash pump 16a was used. Backwash drainage 1 from sand filter 13a
8a is returned to the raw water 1 and collected. On the other hand, sand filtration pond 13
In the backwashing water b, treated water 14b of the sand filtration pond 13b is returned through the treated water tank 15b and the backwash pump 16b.
b was used. In the above, the results obtained by driving for three months in summer are shown in Table 1 and FIG. 2, respectively.

[0025]

[Table 1]

The results in Table 1 show the measured values of the numbers of living organisms and corpses of nematodes in the treated water in each process and the mortality of nematodes in the treated water in each process converted from the measured values and the removal in each process. It shows the rate. The lethality referred to here is a value obtained by using the total number of the number of living bodies and the number of dead bodies as a denominator and the number of dead bodies in the process as a numerator, and is a value obtained by combining the dead bodies and living bodies. The behavior of the nematodes will be described according to the flow of FIG. 1. First, a total of 20 to 220/2 liters are found in the raw water, of which about 5% to 21% of the corpses are alive. Most of them are. In the following coagulated sedimentation water subjected to the pre-chlorine dioxide and coagulated sedimentation treatment, the total number is reduced to 10 to 20/2 liters, and all that remains in the coagulated sedimentation are living bodies having mobility. The next ozonated water remains the same, but most are dead. The removal rate remains the same, as most of the corpses remain. Furthermore, in activated carbon treated water, which is the target water, both the number of living organisms and the number of carcasses increase,
The total number is 7 to 147 pieces / 2 liters, indicating that nematodes are growing by activated carbon treatment.

Next, it can be seen that, in the treatment water treated with ultraviolet rays and sand according to the present invention, the total removal rate is 99.5% or more, and only one living body / 2 liter remains, which is clearly removed. . On the other hand, in the case of only the sand filtration process as a control, it can be seen that the total number is slightly increased to 15 to 147 pieces / 2 liters, and it can be seen that the sand filtration process alone cannot perform sufficient removal. Next, in FIG. 2, nematodes in the activated carbon treated water as the target water of the present invention, the ultraviolet ray / sand filtration treated water as the test plot, the sand filtration treated water as the control plot, and the water for back washing of the sand filtration. FIG. 4 shows the results of measurement of the existence state of a kind in a living body, a cadaver, and a stationary body that has lost motility, which is a feature of the present invention. The criteria for the state determination are as follows.
The living body clearly moves in 30 seconds under microscopic observation. A corpse is a straight one that does not move for more than one minute. A stationary body is one that moves slightly within one minute, or one that does not straighten. Each was measured.

The activated carbon treated water, which is the target water, is often determined to be a living body or a corpse, and although it is determined to be a living body, the majority showed clear motility. The number of dead bodies increased by about 2% when the test group was treated with ultraviolet light, but most of them lost much of their motility and were determined to be stationary. It can be seen that by the following sand filtration treatment, although only a part of the living body remains, most of the nematodes have been removed. The number of living organisms and the number of carcasses are slightly increased in the target area only by the sand filtration treatment.

In particular, the number of dead bodies in the treated water was about the same as that of the target water, suggesting the possibility of re-propagation in the sand filtration layer. Further, only a small amount of dead bodies were found in the backwashing water after the ultraviolet / sand filtration treatment water was again subjected to the ultraviolet treatment, indicating that the secondary contamination by the backwashing water was completely prevented. In this test, the backwash wastewater was collected in the raw water contact pond, but as shown in Table 1, most of the coagulated sedimentation and subsequent ozone treatment resulted in inactivation and mortality. It turns out that the present invention works without any problem.

[0030]

As is apparent from the above description, the present invention removes metazoans mixed in the water to be treated, which was difficult in the conventional water treatment, by inputting useless energy. This is extremely advantageous because it can be efficiently, easily and economically removed by a relatively simple treatment such as an ultraviolet irradiation treatment and a sand filtration treatment. In the present invention, in the ultraviolet irradiation treatment, it is only necessary to add an irradiation amount to the extent that metazoans significantly lose their motility.Therefore, the amount of ultraviolet irradiation may be small, and the metazoans that have significantly lost their motility may be subjected to sand filtration. Can be separated. Further, if metazoans accumulated in the sand filtration device are removed by backwashing, the growth of metazoans in the sand filtration device can be suppressed, and metazoans in the backwash water can be treated and removed.

[Brief description of the drawings]

FIG. 1 is a drawing showing an example of a processing system for implementing the present invention.

FIG. 2 shows the results of measurement of the nematode existence state classified into living body, dead body, and stationary body, according to the treatment of the target water of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Raw water 2 Contact pond 3 Chlorine dioxide 4 Treated water 5 Coagulant 6 Coagulated sedimentation ground 7 Treated water 8 Ozone contact pond 9 Treated water 10 Activated carbon contact pond 11 Target water 12 Medium pressure UV lamp type ultraviolet irradiation device 13a, 13b Sand filter pond 14a, 14b Treated water 15a, 15b Treated water tank 16a, 16b Backwash pump 17 Ultraviolet irradiation device 17a Water treated by ultraviolet irradiation device 18a Backwash drainage of sand filter pond 13a 18b Water returned via backwash pump 16b

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 1/50 531 C02F 1/50 560C 560Z 560 1/76 A 1/78 1/76 9/00 502D 1 / 78 502N 9/00 502 502R 503A 504B 503 B01D 29/08 510B 504 520A 540A 29/38 510B (71) Applicant 000001052 Kubota Co., Ltd. 2-47, Shikitsuhigashi, Namiwa-ku, Osaka City, Osaka (71) Applicant 000193508 Waterworks Co., Ltd. 5-48-16 Sakuragaoka, Setagaya-ku, Tokyo (74) The above three agents 100073874 Patent Attorney Hagino Taira (one outside) (72) Inventor Yoshio Hosaka Kasahara-cho, Mito-shi, Ibaraki 978-6 Ibaraki Prefectural Enterprise Bureau (72) Inventor Mutsuo Ito 978-6 Kasaharacho, Mito-shi, Ibaraki Pref.Ibaraki Prefectural Enterprise Bureau (72) Akiya Kenichi Sasaki 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa Prefecture Ebara Research Institute, Inc. (72) Inventor Naohide Matsumoto 11-1, Haneda Asahi-cho, Ota-ku, Tokyo Ebara Corporation (72) Invention Person Tsuneo Kambayashi 1-2-8 Shinsuna, Koto-ku, Tokyo Organo Corporation (72) Inventor Tomoaki Miyanoshita 1-2-8 Shinsuna, Koto-ku, Tokyo Organo Corporation (72) Inventor Yukihiko Tsutsumi 1-47, Shikitsu-Higashi 1-chome, Naniwa-ku, Osaka-shi, Osaka (72) Inventor Katsumi Maeda 3-3-1, Nihonbashi Muromachi, Chuo-ku, Tokyo In-house Kubota Tokyo Co., Ltd. (72) Inventor Hasegawa Takao 5-48-16 Sakuragaoka, Setagaya-ku, Tokyo Waterworks Kiko Co., Ltd. (72) Inventor Mayumi Kurokawa 5-48-16 Sakuragaoka, Setagaya-ku, Tokyo F-term (reference) 4D037 AA01 AA02 AB18 BA18 CA02 CA11 CA12 4D050 AA08 AB06 BB02 BB04 BC09 BD06 CA07 CA15

Claims (5)

[Claims] 1. A treatment method comprising a combination of an ultraviolet irradiation treatment and a sand filtration treatment, wherein water to be treated including metazoans to be treated is passed in the order of the ultraviolet irradiation treatment and the sand filtration treatment. Metazoan removal method. 2. The method according to claim 1, wherein the ultraviolet irradiation is performed at an emission wavelength of 20.
It outputs light of 0 to 300 nm continuously or intermittently, and the total germicidal ultraviolet output at a wavelength of 200 to 300 nm falls within the required dose of 90% or less for the target metazoan in terms of the amount of treated ultraviolet light in terms of the amount of treated water. 2. The method for removing metazoan animals according to claim 1, wherein the metamorphosis of the metazoans is suppressed. 3. The subsequent sand filtration treatment has the function of washing the surface and backwashing the support layer with water, and the backwashing water contains ultraviolet light, an oxidant-based disinfectant such as ozone or a chlorine-based disinfectant. 2. The method of removing metazoan animals according to claim 1, wherein each of the treated waters is used, and the frequency of the backwash is at least once a day. 4. The backwash wastewater discharged from the subsequent sand filtration treatment is treated by a sterilizing means using ultraviolet, ozone, or chlorine-based oxidant-based disinfectant, and then discharged outside the system or a pre-process of each disinfecting means. The method for removing metazoan animals according to claim 1, wherein the animal is collected. 5. A water treatment system comprising a combination of an ultraviolet irradiation device and a sand filtration device, wherein water to be treated including metazoans to be treated is passed through the ultraviolet irradiation device and the sand filtration device in this order. Metazoan removal equipment.