JP2001025800A - Treatment of dredged sludge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treating method of dredged sludge which is capable of separating sand, stones or the like from the sludge in a excellently cleaned state to take out as valuables and improving dehydration efficiency of slurry. SOLUTION: The dredged sludge treating method is by passing the dredged sludge through a vibration screen 4 to separate contaminant, sand and stones from the sludge and after that, a flocculating and settling agent is added into a raw water to dehydrate the sludge, in which a floc is flocculated and settled. The treated water, which is the clean water produced by adding the flocculating and settling agent in the raw water to flocculate and settle the resultant floc, is returned to the vibration screen 4 and sprayed on the vibration screen 4 as the washing water to clean the sand and stones separated by the vibrating screen 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dredged sludge treatment method for dewatering sludge dredged in a dredging work of a port, lake, marsh, river, pond, ditches, and the like.

[0002]

2. Description of the Related Art In a dredging work for a port, a lake, a marsh, a river, a pond, a trench, etc., as a dredging sludge treatment method for dehydrating a dredged sludge, conventionally, a dredged sludge generated in a dredging work is sieved through a vibrating sieve. A sludge treatment method of sequentially separating contaminants, stone blocks, gravel, sand, and the like, slurrying raw water containing fine-grained soil, subjecting the slurry to a filter press to dewater, and forming a dewatered cake is disclosed in Japanese Unexamined Patent Publication No. Hei 8- 25
No. 7317 has been proposed.

[0003]

However, in the conventional method for treating sludge, since sand and gravels are not separated from the sludge in a well-washed state, contaminants and fine-grained soil are contained in the sand and gravels. And degrades the commercial value of sand and gravel, etc., and makes it difficult to reuse as valuables.In addition, when dewatering the slurry using a filter press, the processing efficiency is extremely high due to clogging of the filter, etc. There was a problem that it was not possible.

The present invention has been made in view of the above points, and can separate sand, gravels, and the like from sludge in a well-washed state, and can extract the valuables as valuables. It is an object of the present invention to provide a dredged sludge treatment method that can be enhanced.

[0005]

In order to achieve the above object, a method for treating dredged sludge according to the present invention comprises the steps of: passing dredged sludge generated by dredging work through a vibrating sieve to remove at least sand,
Separation of gravel, floc generated by adding a coagulating sedimentation agent to the separated raw water, coagulation and sedimentation into a slurry, and in a dredged sludge treatment method of dewatering the slurry, adding a coagulation sedimentation agent to the raw water The method is characterized in that treated water as clean water after flocculation and sedimentation of flocs is returned to the vibrating sieve and sprinkled on the vibrating sieve as washing water, and sand and gravel separated by the vibrating sieve are washed. In the sludge treatment method, magnetism may be applied to raw water to which the coagulating sedimentation agent is added, and magnetism may be applied to sludge supplied to the vibrating sieve.

[0006]

[Function] The dredged sludge generated by the dredging work is put into a sludge storage tank, for example, where stones and large gravels are removed therefrom, and then subjected to a vibrating sieve, where impurities, sand and gravel are separated from the sludge. You. Raw water after separation of impurities, sand and gravel,
For example, it is temporarily stored in a raw water tank and then sent to a stirring reaction tank where a predetermined amount of a coagulating sedimentation agent is added. As the coagulating sedimentation agent, for example, an agent having a composition of a natural mineral mainly composed of alumina silicate can be used.

Here, the raw water to which the coagulating sedimentation agent is added includes:
If magnetized water (active water) is generated by applying magnetism, it is possible to promote fusion with the coagulating sedimentation agent. Further, if magnetism is applied to the sludge supplied to the vibrating sieve to generate magnetized water (activated water), the sludge is activated, and contaminants (garbage, wood chips,
Floats), gravel and sand can be separated well.

The raw water to which the coagulating sedimentation agent has been added is sent to, for example, a sedimentation tank adjacent to the stirring reaction tank, where flocs in the raw water are coagulated and settled to form a slurry, and the treated water of the water is converted into a slurry. After being once stored in the treated water tank, it is returned to the vibrating sieve as washing water. In a vibrating sieve, this washing water is sprinkled on sand and gravel separated by vibration, and sand and gravel are washed,
The diluted raw water containing washing water is sent to a raw water tank. On the other hand, the slurry is sent to, for example, a filter press and dewatered by compression and filtration. The fine-grained soil is returned to a dewatered cake, and the filtrate is returned to a raw water tank.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 and FIG. 2 show a configuration diagram of a treatment facility for carrying out a sludge treatment method. Reference numeral 1 denotes a sludge storage tank for storing the dredged sludge generated by the dredging operation, and a stirrer 1a for stirring by rotating a stirring blade by a motor, and an unloading conveyor 1b for unloading precipitated stone blocks and gravel to another container.
And a pump P1 for pumping sludge from which stone blocks and gravels have been removed to a vibrating sieve 4 described below.

Reference numeral 2 denotes a fresh water tank for introducing and storing middle water (fresh water) such as a river. The fresh water is sent to the raw water tank 3 by a pump P3 provided in the tank. Also, Shimizu is pumped by pump P2.
It is supplied to a sludge storage tank 1, a sedimentation tank 7, a slurry tank 8, and a filter press 10, which will be described later. A raw water tank 3 is provided adjacent to the fresh water tank 2. In the raw water tank 3, together with fresh water sent from the fresh water tank 2, raw water sent from a vibration sieve 4 described later is put. Further, a stirrer 3a is provided in the raw water tank 3, and a pump P4 for sending raw water to a stirring reaction tank 6 described later.
Is provided. A magnet device MG2 is provided in a pipe line 15 for sending raw water from the pump P4 to the stirring reaction tank 6, which applies magnetism to the sent raw water and sends it to the stirring reaction tank 6 as magnetized water. As the magnet device MG2, an electromagnet or a permanent magnet is used to generate a sufficient magnetic flux in the passage of the raw water, and the raw water passing therethrough is magnetized water.

Reference numeral 4 denotes a vibrating sieve, which vibrates the sludge sent from the sludge storage tank 1 by the pump P1 to separate contaminants (garbage, wood chips, suspended matter), gravel, and sand from the sludge. The gravel is carried out to the gravel container 4a. In particular, a magnet device MG1 is provided in a pipe line 14 for pumping the sludge from the sludge storage tank 1 by the pump P1, and applies magnetism to the sludge to be sent to the vibrating sieve 4 as magnetized water.
Send to As described above, an electromagnet or a permanent magnet is used as the magnet device MG1 to generate a sufficient magnetic flux in the sludge passage and generate magnetized water.

A liquid cyclone 4b is provided on the upper part of the vibrating sieve 4, and the mud flowing down to the lower vibrating sieve storage tank 4c is sent to the liquid cyclone 4b by the pump P11, and the mud is circulated for treatment. Further, a pipe 5 is laid on the vibrating sieve 4 so as to return the treated water subjected to the coagulation and sedimentation treatment from a treatment water tank 9 below a sedimentation tank 7 as washing water, and the washing returned through the pipe 5 Water (processed water) is sprinkled over the vibrating sieve 4 to wash sand and gravel. The raw water overflowing the vibrating sieve storage tank 4 c of the vibrating sieve 4 is piped so as to return to the raw water tank 3.

In FIG. 2, reference numeral 6 denotes a stirring reaction tank into which raw water pumped from the raw water tank 3 by the pump P4 through the pipe line 15 and the magnet device MG2 is put. The stirring reaction tank 6 includes a motor-driven stirrer 6a and a coagulating sedimentation agent. A coagulating sedimentation agent supply device 6b for supplying is provided. The magnet device MG2 applies magnetism to the raw water to promote the fusion with the flocculating and settling agent, thereby facilitating the formation of flocs. As the coagulating sedimentation agent, for example, an agent having a composition of a natural mineral mainly composed of alumina silicate is used. A settling tank 7 is provided in addition to the stirring reaction tank 6, and the treated water at the upper portion overflowing the settling tank 7 is sent to a treated water tank 9, and the aggregated sediment collects at the bottom of the settling tank 7.

Reference numeral 8 denotes a slurry tank for temporarily storing coagulated sediment (slurry) sent from the bottom of the settling tank 7. Reference numeral 9 denotes a treatment water tank for storing the treatment water overflowed from the upper part of the sedimentation tank 7, and as described above, the pipe line 5 for sending the treatment water from this treatment water tank 9 to the vibrating sieve 4 as washing water is laid, and The treated water is returned to the upper part of the vibrating sieve 4 by the pump P10 provided in the above and sprinkled. Further, a pump P7 disposed in the treated water tank 9 sends the treated water to the discharge tank 11. The discharge tank 11 is provided with a stirrer 11a, a PH meter, a neutralizing liquid supply device 11b, and a pump P8, and neutralizes and discharges the treated water.

Reference numeral 10 denotes a high-pressure filter press which filters the slurry sent from the slurry tank 8 by the pump P6, sends the filtrate to a filtrate water tank 12, and discharges the compressed and filtered dewatered cake by a dewatering cake conveyor 10a. It is sent to the container 10b. A pump P9 is provided in the filtrate water tank 12, and the filtrate is sent to the raw water tank 3 by the pump P9.

Next, a method for treating dredged sludge carried out using the sludge treatment equipment having the above-described configuration will be described. Dredged sludge generated by dredging work is put into a sludge storage tank 1. The inside of the sludge storage tank 1 is stirred by the stirrer 1a, and the settled stone blocks and large gravels are carried out to another container by the carry-out conveyor 1b, and the sludge from which the stone blocks and large gravels have been removed is vibrated by the vibrating sieve 4 by the pump P1. To be pumped. On the other hand, middle water (fresh water) such as a river is introduced into the fresh water tank 2, the fresh water in the fresh water tank 2 is sent to the raw water tank 3 by the pump P3, and the fresh water is sent to the sludge storage tank 1 by the pump P2. It is sent to a settling tank 7, a slurry tank 8, and a filter press 10.

Pipe 14 and magnet device MG by pump P1
The sludge pumped to the vibrating sieve 4 through 1 is vibrated, and the muddy water is circulated through the vibrating sieve storage tank 4c and the liquid cyclone 4b, whereby contaminants (garbage, wood chips, suspended matter), gravel, sand Is separated, and the sand and gravel are carried out to the gravel container 4a.

At this time, the sludge sent from the sludge storage tank 1 is magnetized and magnetized by the magnet device MG1 disposed in the pipeline 14, so that the sludge is activated, and the sludge is contaminated with contaminants ( (Garbage, wood chips, suspended matter), gravel and sand are well separated. Further, during the processing of the vibrating sieve 4, the treated water returned through the pipe line 5 is sprinkled from above the vibrating sieve 4 as washing water. As a result, sand and gravel are washed by the washing water, and fine-grained soil attached to the sand and gravel is removed.
Even if there is a mud lump, the lump of mud is easily erased by sprinkling of the washing water, so that the gravel separated in the gravel container 4a can be taken out as a valuable material having commercial value.

The sludge overflowing from the vibrating sieve storage tank 4c of the vibrating sieve 4 (raw water after separation of gravel) is supplied to the raw water tank 3
The raw water is diluted with the treated water returned through the pipe line 5, so that the raw water can be diluted and the subsequent dehydration in the filter press 10 can be performed efficiently.

The raw water in the raw water tank 3 is pumped by the pump P4.
It is sent to the stirring reaction tank 6 through the pipe 15. In the stirring reaction tank 6, a flocculating sedimentation agent (for example, a chemical having a natural mineral composition mainly composed of alumina silicate) is supplied from the flocculating sedimentation agent supply device 6b while stirring with the stirrer 6a. At this time, since the raw water in the reaction tank 6 is magnetized water (activated water) by applying magnetism by the magnet device MG2 provided in the conduit 15, the fusion with the coagulating sedimentation agent is promoted, and the efficiency is easily increased. Flock is often formed. Then, the raw water is supplied to the stirring reaction tank 6.
Is sent to the sedimentation tank 7 where flocs of mud in the raw water aggregate and settle, and the aggregated sediment collects at the bottom of the sedimentation tank 7 to form a slurry.

On the other hand, the treated water overflowing the sedimentation tank 7 is sent to the treated water tank 9, and this treated water is water when floc flocculates and settles, and is close to fresh water. Then, the treated water in the treated water tank 9 is sent to the vibrating sieve 4 as washing water through the pipe 5 by the pump P10,
As described above, the vibrating sieve 4 is used for cleaning sand and gravel. The treated water in the treated water tank 9 is sent to the discharge tank 11 by another pump P7. In the discharge tank 11, the neutralizing agent is added by the neutralizing liquid supply device 11b while being stirred by the stirrer 11a. The treated water is neutralized and discharged through a pump P8.

On the other hand, the slurry collected at the bottom of the settling tank 7 is sent to a slurry tank 8 through a pump P5.
The slurry in the slurry tank 8 is sent to the filter press 10 by the pump P6. In the filter press 10,
The slurry sent from the slurry tank 8 by the pump P6 is pressed into the pressure chamber, and filtered by batch processing while applying pressure. The filtrate is sent to a filtrate tank 12, and the compressed and filtered dehydrated cake is dried by a dehydrated cake conveyor 10a.
To the unloading container 10b. The filtrate sent to the filtrate water tank 12 is returned to the raw water tank 3 by the pump P9, and is used again as raw water.

As described above, the treated water as the clean water after coagulation and sedimentation by adding the coagulating sedimentation agent to the raw water is returned to the vibrating sieve 4 through the pipe line 5, and is washed from above the vibrating sieve 4 as washing water. Due to water sprinkling, sand and gravels are washed well, fine-grained soil attached to sand and gravels is removed, and mud lumps are also removed. Separated gravels can be taken out as valuable products with commercial value. . Further, the treated water used as the washing water is reused as the water close to the fresh water from the stirred reaction tank 6 into which the coagulating sedimentation agent has been added, so that there is no waste compared with the case where another fresh water is used, and the raw water is diluted. Therefore, the efficiency of solid-liquid separation and dehydration can be improved.

Further, the stirring reaction tank 6 is provided with a magnet device MG.
2 to supply raw water that is magnetized water (activated water) by applying magnetism, fusion with the coagulating sedimentation agent is promoted, flocs can be formed efficiently, and coagulation in the sedimentation tank 7
Sedimentation, that is, slurrying can be performed efficiently.
Also, the sludge sent from the sludge storage tank 1 to the vibrating sieve 4
Since magnetism is applied by the magnet device MG1 to form magnetized water, the sludge is activated, and contaminants (garbage, wood chips, suspended matter), gravels, and sand can be satisfactorily separated from the sludge.

[0025]

As described above, according to the dredged sludge treatment method of the present invention, the treated water after coagulation and sedimentation is returned to the vibrating sieve, and water is sprinkled from the vibrating sieve as washing water. Sand and gravel separated from sludge can be taken out as valuable resources with commercial value because the gravel and gravel are well washed. In addition, the treated water used as the washing water reuses water close to the fresh water from the stirred reaction tank charged with the coagulating sedimentation agent, so that there is no waste compared with the case where another fresh water is used, and
Since the raw water is diluted and processed, the efficiency of solid-liquid separation and dehydration can be improved.

Further, if magnetized water is applied to the raw water to which the coagulating sedimentation agent is added to form magnetized water (active water), the fusion with the coagulating sedimentation agent is promoted, and flocs can be efficiently formed, and flocculants can be formed. Sedimentation can be performed efficiently. Also,
Applying magnetism to the sludge to be supplied to the vibrating sieve to produce magnetized water (activated water) activates the sludge and separates contaminants (garbage, wood chips, suspended matter), gravels and sand from the sludge. Can be.

[Brief description of the drawings]

FIG. 1 is a half configuration diagram of one of treatment equipment for implementing a dredged sludge treatment method of the present invention.

FIG. 2 is another half configuration diagram of the processing equipment.

[Explanation of symbols]

 4-vibrating sieve 6-stirring reaction tank 7-precipitation tank 9-treatment water tank 10-filter press

Claims (3)

[Claims] Claims 1. A dredged sludge generated by a dredging work is sieved through a vibrating sieve to separate at least sand and gravel from the sludge, and a floc generated by adding a coagulating sedimentation agent to the separated raw water is coagulated and settled. In a dredging sludge treatment method of forming a slurry and dewatering the slurry, treated water as tap water after adding a coagulating sedimentation agent to the raw water to coagulate and settle flocs is returned to the vibrating sieve to wash water. A method for treating dredged sludge, comprising spraying water on the vibrating sieve and washing the sand and gravel separated by the vibrating sieve. 2. The method for treating dredged sludge according to claim 1, wherein magnetism is applied to the raw water to which the coagulating sedimentation agent is added. 3. The method for treating dredged sludge according to claim 1, wherein magnetism is applied to the sludge supplied to the vibrating sieve.