JPH0468964B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electroosmotic dewatering device that applies a DC voltage to sludge generated from a sewage treatment plant and dehydrates it by electroosmotic action.

[Conventional technology]

Generally, sludge generated from sewage treatment plants is dehydrated and then disposed of by landfilling, incineration, composting, etc.

On the other hand, in order to landfill, incinerate, compost, etc. the sludge, it is desirable to sufficiently dewater the sludge.

Therefore, electroosmotic dehydration equipment has been developed that applies DC voltage to a dehydrated cake formed by simple dehydration of sludge using a belt press dehydrator, pressure dehydrator, etc., and dehydrates it by electroosmotic action (for example, , Japanese Patent Publication No. 61-5914 and Japanese Patent Application Publication No. 60-25597
See publication. ) FIG. 9 shows this type of electroosmotic dehydration apparatus, and the reference numeral 11 indicates a simple dehydrated cake 13.
The press belt that presses the is shown. Below this press belt 11 is a filter belt 15.
are arranged at a certain distance, and between this filter belt 15 and the lower part of the press belt 11,
A passage 17 for the dehydrated cake 13 is formed.

This filter belt 15 is supported by an insulating support roller 19 so that the filter belt 15 does not slacken.

Also, the filter belt 15 and the press belt 11
A constant voltage is applied between.

In such an electroosmotic dehydrator, the dehydrated cake 13 with a high moisture content sent to the passage 17 is pressurized by the filter belt 15 and the press belt 11, and when a voltage is applied to the dehydrated cake 13, the dehydrated cake 13 Due to the electroosmotic action in which the moisture inside collects on the filter belt 15 side on the cathode side, the moisture in the dehydrated cake 13 is collected in the filtrate collection chamber 21, and the dehydrated cake 13 can be dehydrated.

However, in such an electroosmotic dehydrator, as the dehydrated cake 13 is dehydrated, the electrical resistance of the dehydrated cake 13 increases and the volume of the dehydrated cake 13 decreases, so it is difficult to apply sufficient voltage or application to the dehydrated cake 13. There was a problem in that it became impossible to apply pressure, and the closer to the exit side of the passage 17 the water could not be removed.

FIG. 10 shows an electroosmotic dehydrator that can apply a sufficient voltage to the dehydrated cake 13 depending on the dehydration state of the dehydrated cake 13. 13
Three press belts 11 for pressing are arranged, and these press belts 11 and filter belt 15
A higher voltage is applied between the dehydrated cake 13 and the outlet side of the passage 17.

FIG. 11 shows an electroosmotic dehydrator that can sufficiently pressurize the dehydrated cake 13 depending on the dehydration state of the dehydrated cake 13. In this electroosmotic dehydrator, the press belt 11 is attached to the filter belt 15. The passage 17 for the dehydrated cake 13 between the press belt 11 and the filter belt 15 becomes narrower from the inlet side to the outlet side.

Further, in the electroosmotic dewatering apparatus as shown in FIG. It gets narrower from the entrance side to the exit side.

In the electroosmotic dehydration apparatus configured as described above, sufficient voltage and pressurizing force can be applied depending on the dehydration state of the dehydrated cake 13, and the dehydrated cake 13 can be applied on the outlet side of the passage 17 as well as on the inlet side. Can be dehydrated.

[Problem to be solved by the invention]

However, in the electroosmotic dewatering apparatus shown in FIGS. 9 to 11, the belts 11 and 15 are supported by the support roller 19 in line contact with each other.
There was a problem in that the belts 11 and 15 were bent and could not be pressurized uniformly, and the pressure and voltage applied to the dehydrated cake 13 were instantaneous, making it impossible to obtain a sufficient dewatering effect.

Also, in the electroosmotic dehydration apparatus shown in Fig. 12,
Since the rotating drum 23 pressurizes the dehydrated cake 13 in line contact with the filter belt 15 side, the pressure and voltage application are instantaneous, resulting in a problem that a sufficient dehydration effect cannot be obtained.

The present invention has been made in order to solve the above-mentioned problems, and aims to provide an electroosmotic dehydration device that can obtain a sufficient dehydration effect by pressing a dehydrated cake from both sides in surface contact with each other. purpose.

[Means to solve the problem]

The electroosmotic dewatering device of the present invention utilizes the electroosmotic phenomenon by applying a DC voltage to sludge generated from a sewage treatment plant, etc. that has been mechanically dehydrated using a centrifugal dehydrator, pressure dehydrator, belt press dehydrator, etc. In an electro-osmotic dewatering device that dewaters water using an electric motor, a number of conductive upper slats are stretched between an electric motor and an upper chain that are arranged facing each other at a predetermined distance in the horizontal direction, and an anode plate is provided at the bottom of each upper slat. An upper slat conveyor that serves as an anode, and a cathode in which a number of lower slats are spanned between an upper slat conveyor that is placed below the upper slat conveyor and that are placed opposite to each other at a predetermined interval in the horizontal direction. a lower slat conveyor, a sludge passage formed between an upper part of the lower slat conveyor and a lower part of the upper slat conveyor, and a sludge passage arranged in the sludge passage; a filter cloth that rotates around the sludge, and a pressurizing mechanism that presses the upper slat or the lower slat toward the sludge passage to sequentially narrow the sludge passage from the inlet side to the outlet side; a voltage applying mechanism that applies a voltage that increases sequentially from the inlet side to the outlet side of the sludge passage between the upper slat and the lower slat; the motor, the sprocket of the upper slat conveyor, and the lower One chain stretched between the sprocket of the side slat conveyor, and one chain stretched between the lower slat conveyor and the sprocket of the filter cloth. The side slat conveyor and filter cloth are configured to run in synchronization.

[Effect]

In the electroosmotic dewatering apparatus of the present invention, a dehydrated cake made of sludge with a high moisture content is sandwiched between filter cloths when passing through a passage between an upper slat conveyor and a lower slat conveyor. In this state, the upper slat conveyor and lower slat conveyor, which run synchronously in a conveyor style, press the lower slat from both sides in surface contact, and the pressing mechanism and voltage application mechanism The dehydrated cake is pressed depending on its dehydrated state and a voltage is applied.

〔Example〕

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, details of the present invention will be described with reference to an embodiment shown in the drawings.

1 to 4 show an embodiment of the electroosmotic dehydration apparatus of the present invention, and in the figures, reference numeral 31
shows the upper slat conveyor. As shown in FIG. 4, this upper slat conveyor 31 has a large number of electrically conductive upper slats 35 stretched between upper roller chains 33 that are arranged facing each other at a predetermined distance in the horizontal direction. It is formed.

As shown in FIGS. 5 and 6, an electrically conductive connecting member 37 having a U-shaped cross section is disposed on the outer surface of the upper slat 35.
A stainless steel plate 39 is arranged at 7.

The stainless steel plate 39 includes, for example, ferrite,
Anode plate 4 made of carbon, conductive ceramic, etc.
1 is placed.

The anode plate 41 and the connecting member 37 are electrically connected.

In order to prevent the upper slats 35 and the anode plates 41 from coming into contact with each other, linings 43 made of, for example, rubber are provided at the front and rear parts of the upper slats 35 and the anode plates 41.

Furthermore, an insulator 45 made of, for example, resin is arranged on the left and right sides of the inner surface of the upper slat 35, and the upper roller chain 33 is fixed to the tip of the insulator 45, as shown in FIG. The attached attachment 47 is fixed.

The upper roller chain 33 is supported by a bracket 49 fixed to a support leg 48. These upper roller chains 33 move and run on an insulator 53 made of resin or the like placed on a bracket 49 in order to prevent loosening and to prevent electrical leakage from the attachment 47.

Further, the upper roller chain 33 is rotationally driven by a reduction motor 55 fixed to the support leg 48 via sprockets 57 arranged on the left and right sides of the upper roller chain 33, as shown in FIG.

On the other hand, below the upper slat conveyor 33,
As shown in FIGS. 3 and 4, a lower part is formed by extending a number of lower slats 61 made of stainless steel between lower roller chains 59 that are arranged opposite to each other at a predetermined interval in the horizontal direction. A slat conveyor 63 is arranged. This lower slat conveyor 63 is used as a cathode.

A passage 67 for the dewatered cake 65 is formed between the lower part of the lower slat conveyor 63 and the upper slat conveyor 31.

A filter cloth 69 is disposed above the lower slat conveyor 63 that forms a passage 67 for the dehydrated cake 65.
It is moving with 3.

In addition, the reduction motor 55 and the upper slat conveyor 3
1 sprocket 57 and lower slat conveyor 6
One chain 56 is stretched between the third sprocket 81 and the third sprocket 81. This one chain 5
6, the tension is adjusted by sprockets 58 and 60.

Then, the lower slat conveyor 63 and the filter cloth 69
A single chain 72 is stretched across the sprocket 70 of.

As described above, the upper slat conveyor 31, the lower slat conveyor 63, and the filter cloth 69 are configured to run synchronously in a conveyor style.

Further, on the inner surface of the lower slat 61, as shown in FIGS. 7 and 8, wheels 71 are arranged, and the wheels 71 are supported by rails 73.
This rail 73 supports only the lower slat 61 forming the passage 67 of the dewatered cake 65;
The rail 73 is fixed to the support leg 48.

A large number of filtrate drainage holes 75 are formed in the center of the lower slat 61 forming the passage 67 of the dehydrated cake 65, and below the passage 67 of the dehydrated cake 65,
As shown in FIG.
is located.

Further, at the center of the outer surface of the lower slat 61, as shown in FIGS. 7 and 8, a guide member 77 made of, for example, a rubber plate is arranged.

Attachments 79 having lower roller chains 59 fixed to their tips are arranged on the left and right sides of the inner surface of the lower slats 61. These lower roller chains 59, like the upper roller chains 33, are supported by brackets 49 fixed to support legs 48, as shown in FIG. These lower roller chains 59 move and run on an insulator 53 made of resin or the like placed on the bracket 49 in order to prevent loosening and electric leakage.

Further, these lower roller chains 59 are operated by a third reduction motor 55 fixed to the support leg 48.
As shown in the figure, it is driven via sprockets 81 placed on the left and right sides of the lower roller chain 59.

In this embodiment, as shown in FIG. 1, the upper slat 35 is pressed toward the lower slat 61, and the passage 67 of the dehydrated cake 65 is narrowed sequentially from the inlet side to the outlet side. Pressure mechanism 83
is located.

This pressure mechanism 83 includes a power supply and pressure roller 8 that presses the upper slat 35 toward the lower slat 61.
5, a pressure roller support member 87 that supports the pressure roller 85 that also serves as a power supply, and a hydraulic cylinder 89 provided on the pressure roller support member 87 at the outlet side end of the passage 67 of the dehydrated cake 65. .

An end of the pressure roller support member 87 on the entrance side of the passage 67 is rotatably supported by a support member 91 fixed to the support leg 48 , and an end of the pressure roller support member 87 on the exit side is supported by the support leg 48 . It is connected to a fixed hydraulic cylinder 89. The pressure roller support member 87 is allowed to swing around the support member 91 .

The power supply and pressure roller 85 is connected to the upper slat 35.
In order to reliably press the lower slat 61, the second
As shown in the figure, they are arranged more densely toward the exit side of the passage 67.

Also, in this embodiment, as shown in FIG.
The upper slat conveyor 31 includes an upper slat 3
5 and the lower slat 61, a voltage applying mechanism 93 is disposed that applies a voltage that gradually increases from the entrance side to the exit side of the passage 67.

This voltage application mechanism 93 consists of a pressure roller 85 that also serves as a power supply and comes into contact with the upper slat 35, three voltage boxes 95 arranged on the upper part of the pressure roller support member 87, and a conductive power supply provided on the lower slat 61. The rail 73 guides the wheel 71 and is connected to the cathode of a DC power supply 97.

Three voltage boxes 95 are connected to the anode of a DC power supply 97;
5 has a voltage that gradually increases from the inlet side to the outlet side of the passage 67. As shown in FIG. 1, one side of the shaft 99 of the power supply/pressure roller 85 is connected to the voltage box 95 via a slip ring.

As shown in FIG. 4, a sludge coagulation tank 101 that stores raw sludge or digested sludge generated from a sewage treatment plant is arranged at the upper end of the support leg 48. As shown in FIG. 3, a polymer flocculant is supplied from a flocculant storage tank 103 by a pump 105.

In the vicinity of this flocculant storage tank 103, there is a gravity dewatering section 10 where the polymer flocculant and agitated sludge are dehydrated.
In addition, a belt press section 113 is formed in which the highly concentrated sludge dehydrated in the gravity dewatering section 107 is sandwiched between two filter cloths 109 and dehydrated under pressure with rollers 111.

Further, a filtrate separation tank 115 for separating filtrate and gas is arranged near the filtrate collection chamber 76,
Pumps 117 are also arranged to discharge the filtrate and gas to the outside.

In the electroosmotic dewatering apparatus configured as described above, raw sludge or digested sludge generated from a sewage treatment plant is stored in the sludge coagulation tank 101, and the coagulant storage tank 1
The polymer flocculant is supplied from 03 to the sludge flocculation tank 101 by the pump 105, and the sludge and the polymer flocculant are sufficiently mixed and stirred in the sludge flocculation tank 101.

These sludges are sent to the gravity dewatering section 107 where they are dehydrated and made into highly concentrated sludge, and these sludges are sent to the belt press section 113 where they are pressed into two filter cloths 109.
The sludge is sandwiched between the rollers 111 and dehydrated under pressure to form a dehydrated cake 65.

Then, this dehydrated cake 65 is sent to a passage 67 between the upper slat conveyor 31 and the lower slat conveyor 63, and when passing through this passage 67, the dehydrated cake 65 is transferred to the upper slat conveyor 31.
and the lower slat conveyor 63 through the filter cloth 69, and in this state, the pressurizing mechanism 83 is moved synchronously with the upper slat conveyor 31 and the lower slat conveyor 63, which run synchronously in a conveyor style.
At the same time, a voltage is applied by the voltage application mechanism 93, and the dehydrated cake 65 is dehydrated by electroosmosis.

The water dehydrated from the dehydrated cake 65 is collected in the filtrate separation tank 115 by the filtrate collection chamber 76 via the filtrate discharge hole 75 of the lower slat 61, and in this filtrate separation tank 115, the filtrate and gas are separated. filtrate and gas are pumped to each pump 1.
17.

The dehydrated cake 65 that has been sufficiently dehydrated by electroosmosis is disposed of by landfilling, incineration, composting, or the like.

In the electroosmotic dewatering apparatus configured as described above, the upper slat 35 is pressed by the power feeding pressure roller 85 against the lower slat 61 supported by the rail 73 via the wheels 71, and the dehydrated cake is 65 are pressed from both sides in surface contact, and since the passage 67 of the dehydrated cake 65 is narrowed from the inlet side to the outlet side, the dehydrated cake 65 is pressurized according to the dehydrated state.

At the same time, the power supply and pressure roller 85
A voltage is applied to the dehydrated cake 65 via the upper slat 35 and the anode plate 41, and the water in the dehydrated cake 65, which is positively charged due to electroosmosis, flows toward the lower slat 61 on the cathode side, and the water is removed. The water passes through the filter cloth 69 and is drained from the filtrate drain hole 75, and the dehydrated cake 65 is dehydrated. The voltage box 95 also connects the passage 67 to the upper slat 35.
Since a high voltage is applied from the inlet side to the outlet side, a voltage is applied to the dehydrated cake 65 according to its dehydrated state.

Therefore, in the electroosmotic dewatering apparatus configured as described above, the upper slat conveyor 31 and the lower slat conveyor 63 form a passage 67 for the dehydrated cake 65, and the passage 67 is directed from the inlet side to the outlet side. Since the pressurizing mechanism 83 is provided to sequentially narrow the dehydrated cake 65, the dehydrated cake 65 is moved between the upper slat 35 and the lower slat 6 depending on the dehydrated state of the dehydrated cake 65.
1 allows pressing with surface contact,
This allows sufficient voltage to be applied,
A sufficient dehydration effect can be obtained.

Further, in the electroosmotic dewatering apparatus configured as described above, the passage 6 of the dehydrated cake 65 is provided in the dehydrated cake 65 between the upper slat 35 and the lower slat 61.
Since a voltage applying mechanism 93 is provided that applies a voltage that increases sequentially from the inlet side to the outlet side of the dehydrated cake 65, it is possible to apply a voltage according to the dehydrated state of the dehydrated cake 65, thereby causing electroosmotic action. can be promoted and a sufficient dehydration effect can be obtained.

Furthermore, in this embodiment, the wheels 71 are arranged on the inner surface of the lower slat 61, and the wheels 71 are moved and run on the rails 73 fixed to the support legs 48, so that the lower slats 61 are securely attached to the rails 73. The lower slat 61 can be prevented from loosening, and the dewatered cake 65 between the upper slat 35 and the lower slat 61 can be reliably pressed by the pressure roller 85 that also serves as a power supply. .

Further, in this embodiment, since the lining 43 made of rubber is applied to the front and rear parts of the upper slat 35 and the anode plate 41, the voltage box 95 supplies power to the upper slat 35 via the pressure roller 85 which also serves as a power supply.
It is possible to reliably apply different voltages to the

Furthermore, since a filter cloth 69 that moves together with the lower slat conveyor 63 is disposed above the lower slat conveyor 63 forming the passage 67, leakage of the dehydrated cake 65 from the filtrate drainage hole 75 is prevented. , only water can be discharged from the filtrate drainage hole 75.

In the above embodiment, an example was explained in which the upper slat 35 was pressed against the passage 67 side of the dewatered cake 65, but the present invention is not limited to the above embodiment, and the lower slat 61 was pressed against the passage 67 side of the dehydrated cake 65. 65
Even if the dehydrated cake 65 is pressurized by pressing it toward the passage 67 side, the same effect as in the above embodiment can be obtained.

Further, in the above embodiment, an example was explained in which three different voltages were applied to the dehydrated cake 65.
The present invention is not limited to the above embodiments, and it goes without saying that two different voltages may be applied to the dehydrated cake 65, for example.

Furthermore, if the dehydrated cake 65 of the passage 67 is insulated for each section where different voltages are applied, and the dehydrated cake 65 in the sections where different voltages are applied are electrically connected to the cathode of the DC power supply device 97, Different voltages can be reliably applied to the dehydrated cake 65.

〔Effect of the invention〕

As described above, in the electroosmotic dehydration apparatus of the present invention, a DC voltage is applied to sludge generated from a sewage treatment plant, etc., which has been mechanically dehydrated using a centrifugal dehydrator, a pressure dehydrator, a belt press dehydrator, etc. In an electroosmotic dewatering device that dewaters water using electroosmotic phenomenon, a large number of electrically conductive upper slats are spanned between an electric motor and an upper chain that are arranged facing each other at a predetermined interval in the horizontal direction, and each upper slat is An upper slat conveyor serving as an anode with an anode plate provided at the bottom, and a lower chain disposed below the upper slat conveyor and facing each other at a predetermined distance in the horizontal direction. A lower slat conveyor serving as a cathode over which slats are stretched, a sludge passage formed between the upper part of this lower slat conveyor and a lower part of the upper slat conveyor, and a sludge passage arranged in this sludge passage. A filter cloth rotating around the lower slat conveyor and the upper slat or the lower slat are pressed toward the sludge passage, so that the sludge passage is sequentially moved from the inlet side to the outlet side. A pressure mechanism that narrows the
a voltage applying mechanism that applies a voltage that increases sequentially from the inlet side to the outlet side of the sludge passage between the upper slat and the lower slat; the motor, the sprocket of the upper slat conveyor, and the lower One chain stretched between the sprocket of the side slat conveyor, and one chain stretched between the lower slat conveyor and the sprocket of the filter cloth. Since the side slat conveyor and the filter cloth are configured to run in synchronization, when the dewatered cake made of sludge with a high moisture content passes through the passage between the upper and lower slat conveyors, It is pressed from both sides by the upper slat and the lower slat in a surface contact state, and the pressure mechanism and voltage application mechanism can apply sufficient pressure and voltage to the dehydrated cake depending on its dehydration state, A sufficient dehydration effect can be obtained.

[Brief explanation of drawings]

FIG. 1 is a side view showing the passageway of the dehydrated cake shown in FIG. 3 and its vicinity. FIG. 2 is a side view showing the power supply/pressure roller of FIG. 3 and its vicinity.
FIG. 3 is an explanatory diagram showing an embodiment of the electroosmotic dehydration apparatus of the present invention. FIG. 4 is a front view of FIG. 3. FIG. 5 is a plan view showing the upper slat of FIG. 1. FIG. 6 is a longitudinal sectional view taken along the - line in FIG. 5. FIG. 7 is a plan view showing the lower slat of FIG. 1. FIG. 8 is a longitudinal sectional view taken along the - line in FIG. 7. 9 to 12 are side views showing a conventional electroosmotic dewatering device. [Description of symbols of main parts], 31...Upper slat conveyor, 33...Upper roller chain, 35
...Upper slat, 59...Lower roller chain, 6
DESCRIPTION OF SYMBOLS 1... Lower slat, 63... Lower slat conveyor, 65... Dehydrated cake, 67... Passage, 83... Pressure mechanism, 93... Voltage application mechanism.

Claims (1)

[Claims] 1. Dewatering using electroosmosis by applying a DC voltage to sludge generated from a sewage treatment plant, etc. that has been mechanically dehydrated using a centrifugal dehydrator, pressure dehydrator, belt press dehydrator, etc. In an electro-osmotic dewatering device, an electric motor and an anode are arranged facing each other at a predetermined distance in the horizontal direction, and a number of conductive upper slats are stretched between the upper chains, and an anode plate is provided at the bottom of each upper slat. The cathode consists of a number of lower slats stretched between an upper slat conveyor and a lower chain placed below the upper slat conveyor and facing each other at a predetermined distance in the horizontal direction. a lower slat conveyor; a sludge passage formed between the upper part of the lower slat conveyor and the lower part of the upper slat conveyor; and a sludge passage arranged in the sludge passage around the lower slat conveyor. a pressurizing mechanism that presses the upper slat or the lower slat toward the sludge passage to sequentially narrow the sludge passage from the inlet side to the outlet side; a voltage applying mechanism that applies a voltage that increases sequentially from the inlet side to the outlet side of the sludge passage between the slat and the lower slat; and the electric motor, the sprocket of the upper slat conveyor, and the lower sprocket. One chain stretched between the sprocket of the slat conveyor, and one chain stretched between the lower slat conveyor and the sprocket of the filter cloth, and the upper slat conveyor and the lower slat conveyor An electroosmotic dewatering device characterized in that a rat conveyor and a filter cloth are configured to run in synchronization.