JP2003154370A - Method for water treatment/sludge treatment without using chemical - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for water treatment/sludge treatment which can precipitate suspended solids in raw water without using a flocculant and treat sludge efficiently. SOLUTION: At least one of red clay and clay after being dried is pulverized into powder, the powder is added into the raw water containing the suspended solids, and the mixture after being agitated is allowed to stand for a prescribed time, so that the suspended solids are precipitated together with the powder, and the supernatant is taken out. The used powder can be reused after being dried again. The raw water containing the suspended solids or raw sludge is added with the powder, and the mixture is treated after being agitated by a solid-liquid separator to be separated into cake and filtrate. The filtrate is separated into precipitate and supernatant, and the supernatant is taken out.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a water treatment method capable of removing suspended solids from treated water containing a large amount of suspended solids without using a chemical such as a flocculant, and adding no chemical to the treated sludge. The present invention relates to a sludge treatment method capable of treating efficiently.

[0002]

2. Description of the Related Art Conventionally, when treating water containing a large amount of suspended matter (suspended matter), a coagulant such as PAC or a polymer coagulant is added to the water to be treated and the mixture is stirred and then sent to a sedimentation tank. Discharge overflow water based on certain emission standards. When used as treated water, overflow water may be rapidly filtered by sand filtration.

The settled sludge is discharged to the outside of the system for treatment.
In the past, the settled sludge was dried by sun drying, but nowadays it is generally treated by a method of separating it into a cake and a filtrate by a dehydration type sludge treatment device consisting of a suction type or pressure type solid-liquid separation device. A typical example of the dehydration sludge treatment device is a vacuum suction drum type (filter cloth or screen type) or pressure type filter cloth type filter press, belt press, screen press using a screen, and the like. .

In these dehydration-type sludge treatment devices,
In order to efficiently carry out sludge treatment, it is usual to add a flocculant again to the settled sludge before treatment.

[0005]

In the conventional water treatment and sludge treatment methods, a method of adding a flocculant is used in order to coagulate and settle suspended solids in water to be treated or to efficiently perform sludge treatment. However, this method not only costs the cost of the flocculant, but also chemicals remain in the treated water and the dehydrated cake remaining after sludge treatment, which may cause environmental problems. In order to remove the chemicals from the treated water for the purpose of environmental protection, the treated water has to be further subjected to the chemical removal process, which is very expensive. In addition, since dehydrated cakes containing a predetermined amount or more of chemicals are designated as industrial wastes by law, there arises a problem that sludge treatment costs increase.

The present invention has been made in view of the problems of the conventional method of using a coagulant for coagulating sedimentation of suspended solids in water to be treated or for efficiently treating sludge. It is intended to provide a new environmentally friendly water treatment / sludge treatment method capable of precipitating suspended solids in water to be treated without the use of water and efficiently performing sludge treatment.

[0007]

Means and Actions for Solving the Problems To solve the above problems, the present inventor has conducted extensive studies and experiments, and as a result, at least one of red clay and clay was dried and then pulverized into a powdery substance, It was discovered that, when the powdery substance is added to water to be treated containing water, and the mixture is left to stand for a predetermined time after being stirred, the floating substance sediments together with the powdery substance and separates into a precipitate and supernatant water. Then, the present invention has been reached.

That is, the chemical-free water treatment method of the present invention which achieves the above-mentioned object is to dry at least one of red clay and clay and then pulverize it into a powdery substance to prepare water to be treated containing suspended substances. The present invention is characterized in that the powdery substance is added and stirred and then left standing for a predetermined time to precipitate the floating substance together with the powdery substance, and then the supernatant water is taken out.

According to the present invention, the powdery substance has a function as a flocculant for flocculating and suspending the suspended substance in the water to be treated, and the suspended substance is on the filter layer (sand layer) of the filter tank or on the bottom surface of the container. The treated water is separated into supernatant water and a precipitate. Therefore, by removing only the supernatant water from the system, the supernatant water does not need to be further processed for chemical treatment, and the precipitate remaining in the filter tank or container is chemical-free red clay or clay. Can be easily treated without being treated as industrial waste.

The powdery substance precipitated by the above method can be taken out, dried again, and then pulverized to be reused as a powdery substance for precipitation of suspended solids in the water to be treated.

In one aspect of the present invention, red soil is added to water to be treated containing suspended solids, and the mixture is stirred and allowed to stand for a predetermined time so that the suspended solids are allowed to settle with the red soil, and then the supernatant water is removed. Characterize.

In one aspect of the present invention, a chemical-free water treatment method is a method in which at least one of red clay and clay is dried and then pulverized into a powdery substance, which is added to water to be treated containing suspended matter. After adding substances like substances and stirring and mixing, the mixture is treated with a solid-liquid separator to separate into a cake and a filtrate, and the filtrate is separated into a precipitate and supernatant water, and then the supernatant water is taken out. To do.

Since this supernatant water does not contain a coagulant, it does not need to be further processed for chemical removal, and the cake and filtrate precipitates do not contain a coagulant, so that it should be treated as industrial waste. It can be easily processed without receiving.

In one aspect of the present invention, the cake and filtrate precipitate produced by this method can be taken out, dried and then pulverized into a powdery substance, which can be added to the water to be treated and reused.

In one aspect of the present invention, at least one of red clay and clay is dried and then pulverized into a powdery substance, the powdery substance is added to the sludge to be treated, and the mixture is stirred and mixed. There is provided a sludge treatment method using no chemicals, which comprises treating with a liquid separation device to separate a cake and a filtrate, separating the filtrate into a precipitate and supernatant water, and then removing the supernatant water.

By using a powdery substance as a coagulant, it is possible to effectively form a good cake (cake having an appropriate water content) without using any other coagulant, and to achieve efficient sludge treatment. In addition, since the formed cake does not contain chemicals, it can be easily disposed of without being treated as industrial waste.

In one aspect of the present invention, the cake and filtrate precipitate produced by this sludge treatment method can be taken out, dried and then pulverized into a powdery substance, which can be added to the sludge to be reused. it can.

In one aspect of the present invention, a chemical-free water treatment method is a method in which at least one of red clay, clay and carbide is dried and then pulverized into a powdery substance, and the powdery substance is dissolved in water. An aqueous solution is prepared, and a vacuum suction is performed from the inside of the cylindrical screen drum submerged in the aqueous solution to form a filter layer made of the powdery substance on the outer circumference of the screen drum in advance, and this filter layer is formed on the outer circumference. The treated water is filtered by performing vacuum suction from the inside of the filter layer of the screen drum in a state where the screen drum is submerged or semi-submerged in the treated water.

Also in this method, by forming a filter layer using a powdery substance as a coagulant, it is possible to effectively form a good cake on the outer periphery of the filter layer of the cylindrical screen without using another coagulant. In addition to being able to efficiently perform water treatment, the formed cake can be easily disposed of without being treated as industrial waste.

It is also possible to carry out continuous filtration by filtering the water to be treated by this method while rotating the screen drum, and scraping off the filter cake layer formed on the outer periphery of the filter layer of the screen drum with a scraper. .

It is also possible to treat the cake of cake scraped off by this method with a solid-liquid separator to separate it into a cake and a filtrate, separate the filtrate into a precipitate and supernatant water, and then take out the supernatant water. it can. When filtration is performed with the screen drum submerged in water, the cake cake scraped off is a dehydrated cake, and therefore solid-liquid separation is not necessary.

Further, the cake and the precipitate or the dehydrated cake taken out by this method can be dried again and then pulverized to be reused as a powdery material.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. In the present specification, the term "clay" means a rock mainly composed of clay minerals, which has plasticity when kneaded with an appropriate amount of water in soil, exhibits plasticity when dried, and sinters when burned at a high temperature. However, "red soil" means iron-containing, reddish-yellow clay, and includes red-yellow soil, dark-red soil, and red-ball soil. As a result of the experiment, it was found that among the red soil, the red soil called "Kunigami merge" in Okinawa Prefecture has a large agglomeration effect and is effective. The Kokuryo Merge is a red soil distributed in mountains such as the northern part of Okinawa main island, eastern Kume Island, Ishigaki Island, Iriomote Island, etc. As the red soil, many other types of red soil can be used for the purpose of the present invention. As clay, many kinds of clay such as Shigaraki clay and porcelain clay can be used.

In order to prepare a powdery substance of red soil or clay used in the present invention, the red soil or clay is sufficiently dried by a hot air dryer or the like, or is dried by sun drying, and then powdered by a pulverizer or the like. Crush up to. The particle size of each particle of the powdery substance is not particularly limited, but it is effective that the particle size is as small as possible, and 0.005 mm or less is preferable.

In the case where suspended solids are settled together with powdery substances on the filtration layer of the filtration tank or the bottom surface of the container by treating the water to be treated in the filtration tank or container, after adding a predetermined amount of the powdery substances to the water to be treated. After sufficiently stirring and mixing, leave still for a predetermined time. The amount of powdery substance added and the standing time vary depending on the nature of the water to be treated, the type of powdery substance, the purpose of treatment, and the like. Generally, the larger the amount of the powdery substance added, the faster the rate of flocculation and settling of floating substances, and the longer the standing time, the greater the rate of precipitation of floating substances.

The powdery substance having the floating substance remaining on the surface thereof after the supernatant water in which the floating substance has substantially settled is taken out of the system is taken out and dried by heating.
Most of the floating substances adhering to the surface are burnt out or scattered, and the dried powdery substance can be reused as a powdery substance added in the next water treatment step by pulverizing again. In this case, since the powdery substance has already been pulverized into a fine powder in the first crushing step, the powdery substance is, for reuse, formed into relatively large particles or lumps having a particle size of, for example, 5 mm to 10 mm. Even if it is present, the aggregation effect can be exhibited by adding it to the water to be treated and stirring it.

As the powdery substance, red clay or clay may be used alone, or both may be mixed and used at an appropriate ratio. When both are mixed, the mixing ratio may be set to an appropriate value depending on the purpose of use as a powdery substance.

[0028] Among the red soil, the one that has the property of easily dissolving in water and decomposing like the national territory merge, by adding the red soil collected without the step of drying and crushing directly to the water to be treated and stirring it. It was found that a certain degree of flocculation and sedimentation effect of suspended solids was achieved. However, in order to obtain a sufficient effect, it is desirable to dry and grind the red clay and add it as a powdery substance. Even if red clay that does not readily dissolve in water and other clays are added directly to the water to be treated without drying and crushing, the effect of aggregating and suspending suspended solids is not rare.

A water treatment method in which a powdery substance is added to water to be treated, stirred and mixed, and then the mixture is treated by a solid-liquid separator to separate a cake and a filtrate, that is, an auxiliary agent for forming the powdery substance into a cake. In this method, the mixing ratio of the powdery substance to the water to be treated needs to be much higher than that in the case of the water treatment method in which the suspended solids in the water to be treated are settled together with the powdery substance. The mixing ratio varies depending on the nature of the water to be treated, the type of powdery substance, the type of solid-liquid separator used, and the like. As an example, US Pat. No. 5,618,
When the solid-liquid separator of the same type as the solid-liquid separator described in No. 424 was used, the optimum cake was formed when the mixing ratio was 1: 1.

Also in this method, the filtrate separated from the cake by the solid-liquid separator still contains a large amount of powdery substances, but when this filtrate is allowed to stand, the filtrate is rapidly separated into supernatant water and a precipitate. However, the supernatant water can be taken out of the system. In addition, the precipitate remaining after removing the supernatant water from the cake and the filtrate can be reused in the next water treatment step by drying and pulverizing the precipitate again to give a powder. Further, since the cake and the precipitate do not contain any chemicals, they do not need to be treated as industrial waste and can be easily discarded.

The above powdery substance can be effectively used as a flocculant even when general sludge such as sludge is subjected to a dehydration treatment by applying it to a solid-liquid separator. In this case, the mixing ratio of the sludge to be treated and the powdery substance varies depending on the purpose of use, but it is preferably about 1: 1 to 1: 2.

A chemical-free water treatment method according to one embodiment of the present invention is a method in which at least one of red clay, clay, and carbide is dried and then pulverized into a powdery substance, and the powdery substance is dissolved in water. An aqueous solution is prepared, and a vacuum suction is performed from the inside of the cylindrical screen drum submerged in the aqueous solution to form a filter layer made of the powdery substance on the outer circumference of the screen drum in advance, and this filter layer is formed on the outer circumference. The water to be treated is filtered by performing vacuum suction from the inside of the filter layer of the screen drum with the screen drum thus submerged in the water to be treated or submerged in water.

In this embodiment, as the red soil and clay, the various red soil and clay of the above embodiment can be used. As the charcoal, charcoal, vegetable charcoal such as coconut charcoal activated carbon and the like are preferable. Any one of red clay, clay, and carbide may be used alone, or two or more kinds may be mixed and used for private use.

An aqueous solution in which a powdery substance is dissolved in water is housed in a container 1 and a cylindrical screen drum 3 is placed in the aqueous solution 2 in a submerged state, as shown in the schematic sectional view of FIG. Examples of the cylindrical screen drum 3 include:
Nagaoka 210-type suction dehydrator (US Pat. No. 5,61
A device of the same type as the device described in No. 8,424) can be used. This cylindrical screen drum 3 is composed of a wedge wire screen which can be rotationally driven and whose both ends are closed.
One end thereof is connected to a vacuum suction device (not shown) through the filtered water outlet pipe 4, and the inside of the cylindrical screen can be depressurized by operating this vacuum suction device.

By performing vacuum suction in the state of FIG.
The water content of the powdery substance aqueous solution 2 is sucked and discharged from the filtrate outlet pipe 4, and a filter layer 5 made of the powdery substance is formed on the outer periphery of the cylindrical screen drum 3 as shown in FIG. When the filter layer 5 is formed in this manner, the aqueous solution 2 of the powdery substance is taken out from the container 1, and the preparation of the cylindrical screen drum 3 on which the filter layer 5 of the powdery substance is previously formed on the outer periphery is completed.

When the water to be treated is filtered using this cylindrical screen drum 3, the container 1 is filled with the water to be treated, and vacuum suction is performed while the cylindrical screen drum 3 is submerged in the water to be treated. Filtration is performed so that filtered water is taken out from the filtered water outlet 4.

Further, as shown in FIG. 3, the treated water inlet 6
The water 7 to be treated is poured into the container 1, and the cylindrical scclean drum 3 in a submerged state is rotationally driven while performing vacuum suction. The water filtered by this is taken out from the filtrate outlet pipe 4, and the solid content in the water to be treated is accumulated as a cake layer 8 on the outer periphery of the filter layer 5. The cake layer 8 is scraped off by a scraper 9 arranged close to the filter layer 5 of the cylindrical screen drum 3 and discharged to the outside of the container. This operation allows continuous filtration of the water to be treated.

Further, as shown in FIG. 4, the treated water inlet 6
The treated water 7 is poured into the container 1 from the above, and the semi-submerged cylindrical screen drum 3 is driven to rotate while vacuum suction is performed, so that the filtered water is taken out from the filtrate outlet 4 and the filter layer On the outer circumference of 5, the solid content in the water to be treated is accumulated as a cake layer 8. The cake layer 8 is scraped off by a scraper 9 arranged above the water to be treated 7 in the vicinity of the filter layer 5 of the cylindrical screen drum 3 and discharged to the outside of the container. This operation allows continuous filtration of the water to be treated.

[0039]

[Example] 1. Use of Red Soil / Clay as a Flocculant in Water Treatment (Example 1) Red soil turbid water (concentration of suspended solids 20,000 mg / L) obtained from the Kokuryo merger of Okinawa Prefecture was used as water to be treated. Orion Machinery Co., Ltd.'s hot air direct fire dryer (ORIONJET HEATER HPS 310E)
(Outputting 30,000 kcal / hour) was dried with hot air at a temperature of 200 ° for 2 hours and then crushed by hammering to form a powdery substance having a particle size of 0.005 mm or less. 10 cc of this powdery substance was added to 300 cc of water to be treated contained in a beaker, and the mixture was stirred and mixed, and then allowed to stand for 5 hours. The water to be treated was separated into precipitates of suspended solids and powdery substances and supernatant water, and the precipitates were deposited at the bottom of the beaker. When this clear water was measured with a fluorometer, the transparency was 82 mm.
Met. The concentration of suspended solids in the supernatant water was measured and found to be 98 mg / L. The ratio of supernatant water to precipitate was 9: 1.

(Example 2) Shigaraki clay, which is a pottery clay produced in Shigaraki Town, Shiga Prefecture, was dried as a powdery substance by the method of Example 1,
The water to be treated was treated under the same conditions as in Example 1 except that the pulverized product was used. The water to be treated was separated into precipitates of suspended solids and powdery substances and supernatant water, and the precipitates were deposited at the bottom of the beaker. When this supernatant water was measured with a fluorometer, the transparency was 56 mm. The concentration of suspended solids in the supernatant water was measured and found to be 155 mg / L. The ratio of supernatant water to precipitate was 9: 1.

(Example 3) As a powdery substance, Shigaraki red clay, which is a pottery clay produced in Shigaraki Town, Shiga Prefecture, was dried by the method of Example 1,
The water to be treated was treated under the same conditions as in Example 1 except that the pulverized product was used. The water to be treated was separated into precipitates of suspended solids and powdery substances and supernatant water, and the precipitates were deposited at the bottom of the beaker. When the supernatant water was measured with a fluorometer, the transparency was 32 mm. The concentration of suspended solids in the supernatant water was measured and found to be 306 mg / L. The ratio of supernatant water to precipitate was 9: 1.

(Example 4) As a powdery substance, the cake obtained by the dehydration treatment by the solid-liquid separation device of Example 6 described later was dried by the method of Example 1 and crushed into lumps having a particle size of about 5 mm. The water to be treated was treated under the same conditions as in Example 1 except that the regenerated powder substance was used. The water to be treated was separated into precipitates of suspended solids and powdery substances and supernatant water, and the precipitates were deposited at the bottom of the beaker. When this supernatant water was measured with a fluorometer, the transparency was 82 mm. The concentration of suspended solids in the supernatant water was measured and found to be 98 mg / L.

(Comparative Example 1) When 300 cc of the water to be treated was placed in a beaker and allowed to stand for 5 hours without any treatment, the water to be treated was slightly suspended with slight precipitation. , The ratio of supernatant water to sediment is 9.5:
It was 0.5. The transparency was 29 mm and the concentration of suspended solids was 344 mg / L.

Comparative Example 2 The water to be treated was treated under the same conditions as in Example 1 except that a commercially available powdery inorganic flocculant Cosmobond ™ was used as the powdery substance. The water to be treated was separated into precipitates of suspended solids and powdery substances and supernatant water, and the precipitates were deposited at the bottom of the beaker. When this supernatant water was measured with a fluorometer, the transparency was 74 mm.
When the concentration of suspended solids in the supernatant water was measured, it was 111
It was mg / L. The ratio of supernatant water to precipitate was 8: 2.

(Example 5) The same red soil turbid water as in Example 1 was used as the water to be treated. Naturally dried (sun dried) for 1 month after collecting the national territory merger of Okinawa Prefecture, add 10 cc to the treated water 300 cc in a beaker without stirring and add it to the treated water 300 cc without stirring. After that, it was left to stand for 5 hours. The water to be treated was separated into suspended solids, a red soil precipitate, and supernatant water, and the precipitate settled at the bottom of the beaker. When the supernatant water was measured with a fluorometer, the transparency was 70 mm. The concentration of suspended solids in the supernatant water was measured and found to be 110 mg / L. The ratio of supernatant water to precipitate was 9: 1.

(Example 6) An iron removing device manufactured by Nagaoka Co., Ltd. (of the same type as the device described in Japanese Patent Application No. 2000-324268) was used to treat the groundwater of Kyoto Koji pumping station, and then the filter medium layer of the device was backwashed. Concentration of suspended solids 50,000mg
/ L backwash drainage occurred. This backwash drainage was used as water to be treated. As the powdery material, the powdery material prepared from the same national merger as in Example 1 was used.

10 cc of this powdery substance was added to 300 cc of water to be treated contained in a beaker, and the mixture was stirred and mixed, and then allowed to stand for 5 minutes. The water to be treated was separated into precipitates of suspended solids and powdery substances and supernatant water, and the precipitates were deposited at the bottom of the beaker. When the supernatant water was measured with a fluorometer, the transparency was 35 mm. The concentration of suspended solids in the supernatant water was measured and found to be 274 mg / L. The ratio of supernatant water to precipitate was 7.5: 2.5.

(Example 7) The treated water was treated under the same conditions as in Example 6 except that the red soil produced in Kashiwara-cho, Hyogo Prefecture was dried and pulverized by the method of Example 1 as a powdery substance. The water to be treated was separated into precipitates of suspended solids and powdery substances and supernatant water, and the precipitates were deposited at the bottom of the beaker. When this clear water was measured with a fluorometer, the transparency was 25 mm.
Met. The concentration of suspended solids in the supernatant water was measured and found to be 412 mg / L. The ratio of supernatant water to precipitate was 7.5: 2.5.

(Example 8) The water to be treated was treated under the same conditions as in Example 6 except that Shigaraki clay was dried and pulverized by the method of Example 1 as a powdery substance. The water to be treated was separated into precipitates of suspended solids and powdery substances and supernatant water, and the precipitates were deposited at the bottom of the beaker. When the supernatant water was measured with a fluorometer, the transparency was 20 mm.
Moreover, when the concentration of suspended solids in the supernatant water was measured, it was 540
It was mg / L. The ratio of supernatant water to sediment is 7.5:
It was 2.5.

Comparative Example 3 Water to be treated 300c of Example 6
When c was placed in a beaker and allowed to stand for 5 minutes without any treatment, precipitation occurred and the ratio of the supernatant water to the precipitate was 7.
Although it was 5: 2.5, the transparency was as low as 18 mm and the concentration of suspended matter was 618 mg / L.

Comparative Example 4 The water to be treated was treated under the same conditions as in Example 6 except that a commercially available powdery inorganic flocculant Cosmobond ™ was used as the powdery substance. The water to be treated is separated into suspended matter and flocculant precipitates and supernatant water,
The precipitate settled on the bottom of the beaker. When the supernatant water was measured with a fluorometer, the transparency was 20 mm. Moreover, when the concentration of suspended solids in the supernatant water was measured, it was 540 mg.
It was / L. The ratio of supernatant water to sediment is 6.5: 3.
It was 5.

Consideration on Use of Red Soil / Clay as Flocculant in Water Treatment Comparing Examples 1 to 8 and Comparative Examples 1 to 4, dried and crushed Kokuryo merge in red soil and its reused product It has the highest settling rate and has the best effect on the clarity and the suspended matter concentration of the supernatant water. Also, it can be seen that the national territory merger is superior to the commercially available coagulant in the clarity of the clear water and the concentration of suspended solids. In addition, it can be seen that red soil other than the national land merger is superior to the commercially available coagulant in the clarity of the clear water and the concentration of suspended solids. In addition, the clay Shigaraki clay is dried,
It can be seen that the pulverized powdered substance also has almost the same aggregating effect as the commercially available aggregating agent in the clarity of the supernatant water and the concentration of suspended solids.

2. Use of Red Soil / Clay as a Cake-Forming Aid in Water Treatment (Example 9) Iron Removal Equipment Made by Nagaoka Co., Ltd.
(The same type as the device described in No. 324268) was used to treat the red water generated in Okinawa Prefecture, and then the filter media layer of the device was backwashed, resulting in backwash drainage with a floating substance concentration of 20,000 mg / L. This backwash drainage was used as water to be treated. As a powdery substance, national merger was dried and pulverized by the method of Example 1 to prepare. 1 L of water to be treated and 1 L of powdery substance were mixed (mixing ratio 1: 1), and a 210 type suction dehydrator manufactured by Nagaoka Co., Ltd. (a device of the same type as the device described in US Pat. No. 5,618,424) was used. It was used for dehydration filtration by vacuum suction. As a result, a good cake (water content 55%) of moderate hardness is formed around the screen drum, while 25
0 mL of filtrate was obtained. Approximately 30 minutes after the completion of filtration, sludge (mixture of powder and suspended matter) in the filtrate settles,
The precipitate and the supernatant water were separated at a ratio of about 1: 1. The concentration of suspended solids in the supernatant water was 150 mg / L.

Example 10 As a powdery substance, Example 9 was used.
The cake obtained in 1. was dried by the method of Example 1, and the water to be treated was treated under the same conditions as in Example 9 except that the regenerated powder substance crushed to a particle size of about 5 mm was used. As a result, 650 mL of filtrate was obtained while forming a good cake of moderate hardness around the screen drum. About 30 minutes after the completion of filtration, sludge (mixture of powdery substance and suspended solids) in the filtrate settled, and the precipitate and supernatant water were separated at a ratio of about 1: 1. Suspended matter concentration in supernatant water is 150 mg /
It was L.

(Embodiment 11) An iron removing device manufactured by Nagaoka Co., Ltd. (of the same type as the device described in Japanese Patent Application No. 2000-324268) was used to remove iron from groundwater in the Kyoto Koji pumping station, and then the filter medium layer of the device was reversed. As a result of washing, suspended solids concentration 50,000
Backwash drainage of mg / L occurred. This backwash drainage was used as water to be treated. As the powdery substance, red clay produced in Kashiwara-cho, Hyogo Prefecture, which was dried and pulverized by the method of Example 1, was used. 1 L of water to be treated and 1 L of powdery substance were mixed (mixing ratio 1:
1), dehydration filtration by vacuum suction was performed using a 210 type suction dehydrator manufactured by Nagaoka Co., Ltd. As a result, 250 mL of filtrate was obtained while forming a good cake having an appropriate hardness (water content 55%) around the screen drum.
Five minutes after the completion of filtration, sludge (mixture of powdery substances and suspended materials) in the filtrate settled, and the precipitate and supernatant water were separated at a ratio of about 1: 1. The transparency of the supernatant water was 45 mm, and the concentration of suspended substances in the supernatant water was 197 mg / L.

Comparative Example 5 The treated water was treated under the same conditions as in Example 9 except that 1 L of the powdery substance was mixed with 2 L of the treated water (mixing ratio 2: 1). However, the dehydrated cake had an excessive water content and became muddy, and a filtrate could not be obtained.

(Example 12) As the water to be treated, polluted pond water (no sand filtration) was used. The concentration of suspended solids in this water was 150 mg / L. As a powdery substance, national merger was dried and pulverized by the method of Example 1 to prepare. 1 L of the water to be treated and 1 L of the powdery substance were mixed (mixing ratio 1: 1), and dehydration filtration was performed by vacuum suction using a 210 type suction dehydrator manufactured by Nagaoka Co., Ltd. As a result, 0.2 L of filtrate was obtained while forming a good cake of moderate hardness around the screen drum. About 30 minutes after the completion of filtration, sludge (mixture of powdery substance and suspended solids) in the filtrate settled, and the precipitate and supernatant water were separated at a ratio of about 1: 1. The suspended matter concentration in the supernatant water was 50 mg / L. In addition, this treatment also made it possible to remove chromaticity that could not be removed by sand filtration.

(Comparative Example 6) Treated water under the same conditions as in Example 12 except that the sludge in the pond in which the polluted water was sampled as a powdery substance was dried and crushed by the same method as in Example 1 was used. (Polluted pond water) was treated. As a result, the mixed sludge did not stick to the screen drum of the dehydrator, and solid-liquid separation was not possible. With respect to the filtrate sucked out through the screen, separation of supernatant water and precipitate did not occur.

(Comparative Example 7) Water to be treated (polluted pond water) under the same conditions as in Example 12 except that the soil of a field was dried and pulverized by the same method as in Example 1 as a powdery substance. Was processed. As a result, the mixed sludge did not stick to the screen drum of the dehydrator, and solid-liquid separation was not possible. With respect to the filtrate sucked out through the screen, separation of supernatant water and precipitate did not occur.

Consideration on the Use of Red Soil / Clay as a Cake-Forming Aid in Water Treatment When comparing Examples 9-12 and Comparative Examples 5-7,
It can be seen that the powdery substance obtained by drying and crushing the red soil has an effect comparable to that of the conventional flocculant even as a cake forming aid in sludge dewatering treatment.

3. Use of Red Soil and Viscosity in Sludge Treatment (Example 13) The sludge was dehydrated using a powdery substance as a cake-forming aid. As the sludge to be treated, sludge (sludge mixed with waste oil) collected in Nagaoka Co., Ltd. was used. Example 1 of national land merger as a powdery substance
What was dried and pulverized by the method of 1. was prepared. 1 L of sludge to be treated and 1 L of powdery substance are mixed (mixing ratio 1: 1),
210 type suction dehydrator manufactured by Nagaoka Co., Ltd. (US Pat. No. 5,
Dehydration filtration by vacuum suction was performed using a device of the same type as the device described in No. 618,424). As a result, a good cake (with a moisture content of 8
0%) was formed and about 0.2 L of filtrate was obtained. Five minutes after the completion of filtration, an oil film was formed on the surface of the filtrate, and sludge (mixture of powdery substances and suspended materials) in the filtrate under the oil film was settled, and 95% of precipitate and 5% of supernatant water were obtained. . The clear water has a transparency of 5 mm and the concentration of suspended solids in the clear water is 20.
It was 00 mg / L. 5 hours after the completion of filtration, the filtrate under the oil film was further precipitated, and 70% of the supernatant water and 30% of the precipitate were collected.
was gotten. The transparency of the supernatant water was 15 mm, and the concentration of suspended solids in the supernatant water was 755 mg / L.

(Example 14) Example 1 except that 1 L of the sludge to be treated was mixed with 2 L of the powdery substance (mixing ratio 1: 2).
In the same manner as in No. 3, the sludge was dehydrated by vacuum suction. As a result, a good cake (water content 60%) having an appropriate hardness was formed around the screen drum, and about 0.2 L of filtrate was obtained. Five minutes after the completion of filtration, an oil film is formed on the surface of the filtrate, and sludge (mixture of powdery substances and suspended materials) in the filtrate below the oil film settles, and 95% of the precipitate and 5
%was gotten. The transparency of the supernatant water was 6 mm, and the concentration of suspended solids in the supernatant water was 1600 mg / L. Five hours after the completion of filtration, the filtrate under the oil film was further precipitated, and 60% of supernatant water and 40% of precipitate were obtained. Clear water has a transparency of 50 mm and the concentration of suspended solids in the clear water is 178 mg / L.
Met.

(Example 15) The cake obtained in Example 13 was dried and pulverized, and it was reused as a cake-forming aid for the treatment of new sludge. As the sludge to be treated, the same sludge as in Example 13 (sludge mixed with waste oil) was used. In addition, the cake obtained in Example 13 was used as a cake-forming aid at 200 ° C.
The powdery substance obtained by pulverizing after drying for 3 hours was used. When 400 cc of the sludge to be treated and 400 cc of the powdery substance were stirred and mixed, a change occurred in the mixture, and separated water began to come out. Further, stirring was continued for about 5 minutes to obtain 190 cc of separated water. The remaining mixture was squeezed with a cloth to obtain 10 cc of separated water. The total amount of separated water was 200 cc. 25 dehydrated cakes
The water content was about 90% at 0 cc. The transparency of the separated water after 30 minutes is 15 mm and the concentration of suspended matter is 755 mg / L.
(It seems that the transparency and the concentration of suspended solids will be further improved with time.) Further, observing the state of the dehydrated cake, it seems that this cake can be reused again as a cake forming aid if it is dried and powdered. When the cake and precipitate are reused as a cake-forming aid, separated water is generated during the formation of the mixture of the sludge to be treated and the cake-forming aid as described above. Is difficult to ride on the drum screen, and as a method for dewatering the sludge to be treated,
It has been found that the pressure dehydration method is preferable to the vacuum suction method.

Consideration on Sludge Treatment From Examples 13 and 14, the use of the powdery substance formed a good cake and the sludge settling effect in the filtrate was excellent, and the powdery substance was inferior to the conventional flocculant. It can be seen that there is an effect on the efficient treatment of sludge dewatering. Also,
It can be seen that the treated sludge cake or filtrate precipitate can also be reused as a cake-forming aid by drying and grinding.

[0065]

As described above, according to the present invention, the powdery substance has a function as a coagulant for aggregating and suspending the suspended solids in the water to be treated, and the suspended solids are used to filter the suspended solids (sand layer). ) Settle on top or on the bottom of the container to separate the water to be treated into supernatant water and a precipitate. Therefore, by removing only the supernatant water from the system, the supernatant water does not need to be further processed for chemical treatment, and the precipitate remaining in the filter tank or container is chemical-free red clay or clay. Can be easily treated without being treated as industrial waste.

A powdery substance is added to the water to be treated or the sludge to be treated, and the mixture is stirred and mixed, and the mixture is treated with a solid-liquid separator to separate it into a cake and a filtrate, and the filtrate is separated into a precipitate and a supernatant water. In the method of removing the supernatant water after the reaction, a powdery substance can be used as an aggregating agent to effectively form a good cake (a cake having an appropriate water content) without using any other aggregating agent. In addition, sludge treatment can be achieved efficiently, and since the formed cake does not contain chemicals, it can be easily disposed of without being treated as industrial waste.

Further, also in the method of depositing a powdery substance composed of at least one kind of red clay, clay and carbide as a filter layer on the outer periphery of the cylindrical screen drum to perform water treatment, similarly, the powdery substance is used as an aggregating agent. By using it, it is possible to effectively form a good cake (a cake with an appropriate water content) without using any other flocculant, and it is possible to achieve water treatment efficiently, and the formed cake is Since it contains no chemicals, it can be easily disposed of without being treated as industrial waste.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing an embodiment using a cylindrical screen drum, showing a state of being filled with an aqueous solution of a powdery substance.

FIG. 2 is a cross-sectional view showing a state in which a filter layer is formed on the outer circumference of a cylindrical screen drum.

FIG. 3 is a cross-sectional view showing a method of performing continuous filtration with a cylindrical screen drum submerged in water to be treated.

FIG. 4 is a cross-sectional view showing a method of performing continuous filtration in a state where a cylindrical screen drum is submerged in water to be treated.

[Explanation of symbols]

1 container 2 aqueous solution 3 Cylindrical screen drum 5 filter layers

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) B01D 33/44 B01D 33/36 33/58 C02F 11/14

Claims (14)

[Claims] 1. At least one of red clay and clay is dried and then pulverized into a powdery substance, and the powdery substance is added to water to be treated containing suspended solids, and the mixture is stirred and then allowed to stand for a predetermined time. A method for treating water without using a chemical, characterized in that the suspended substance is allowed to settle with the powdery substance by the method described above, and then the supernatant water is taken out. 2. A water treatment method which does not use chemicals, wherein the powdery substance precipitated by the method according to claim 1 is taken out, dried again, and then pulverized for reuse as a powdery substance. 3. A chemical characterized by adding red soil to water to be treated containing suspended solids, stirring the mixture, and then leaving it to stand for a predetermined time to settle suspended solids together with the red soil, and then removing supernatant water. Unused water treatment method. 4. At least one of red clay and clay is dried and then pulverized into a powdery substance, the powdery substance is added to water to be treated containing suspended solids, the mixture is stirred and mixed, and the mixture is solid-liquid. Treated with a separator to separate into cake and filtrate,
A method for treating water without using a chemical, characterized in that the filtrate is separated into a precipitate and supernatant water and then the supernatant water is taken out. 5. Water containing no chemicals, characterized in that at least one of a cake and a filtrate precipitate produced by the method according to claim 4 is taken out, dried and then pulverized for reuse as a powdery substance. Processing method. 6. At least one of red soil and clay is dried and then pulverized into a powdery substance, the powdery substance is added to sludge to be treated, and the mixture is stirred and mixed, and then the mixture is treated by a solid-liquid separator. A method for treating sludge without using any chemicals, which comprises separating a cake and a filtrate with a filter, separating the filtrate into a precipitate and supernatant water, and then removing the supernatant water. 7. A sludge free from chemicals, characterized in that at least one of a cake and a filtrate precipitate produced by the method according to claim 6 is taken out, dried and then pulverized for reuse as a powdery substance. Processing method. 8. A cylindrical screen in which at least one of red clay, clay and carbide is dried and then pulverized to form a powdery substance, the powdery substance is dissolved in water to prepare an aqueous solution, and the aqueous solution is submerged in the aqueous solution. A filter layer made of the powdery substance is preliminarily formed on the outer periphery of the screen drum by performing vacuum suction from the inside of the drum, and the screen drum having the filter layer formed on the outer periphery is submerged in the water to be treated. A water treatment method using no chemicals, characterized in that the water to be treated is filtered by performing vacuum suction from the inside of the filter layer of the screen drum. 9. The water to be treated is filtered by the method according to claim 8 while rotating the screen drum, and the cake cake layer formed on the outer periphery of the filter layer of the screen drum is scraped off by a scraper and continuously. A water treatment method that does not use chemicals characterized by performing filtration. 10. The cake cake scraped off by the method according to claim 9 is treated with a solid-liquid separator to separate it into a cake and a filtrate, and the filtrate is separated into a precipitate and a supernatant water, and then the supernatant water. A water treatment method that does not use chemicals, which is characterized by taking out water. 11. At least one of red clay, clay and carbide.
The seeds are dried and then pulverized to form a powdery substance, an aqueous solution is prepared by dissolving this powdery substance in water, and vacuum suction is performed from the inside of the cylindrical screen drum submerged in this aqueous solution so that the screen drum A filter layer made of the powdery substance is preliminarily formed on the outer circumference, and vacuum suction is performed from the inside of the filter layer of the screen drum while the screen drum having the filter layer formed on the outer circumference is submerged in the water to be treated. A water treatment method using no chemicals, which comprises filtering the water to be treated. 12. The water to be treated is filtered by the method according to claim 11 while rotating the screen drum, and the cake cake layer formed on the outer periphery of the filter layer of the screen drum is placed above the water to be treated. A water treatment method using no chemicals, which comprises scraping off a dehydrated cake by scraping it with a scraper provided and then performing continuous filtration. 13. A chemical-free water treatment method characterized in that the cake and the precipitate taken out by the method according to claim 10 are dried again and then pulverized and reused as a powdery material. 14. A chemical-free water treatment method, characterized in that the dehydrated cake taken out by the method according to claim 12 is dried again and then pulverized and reused as a powdery material.