JP2010000437A - Screw press having flocculation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screw press which is directly and continuously provided with a flocculation device to which a technology of a line mixer is applied. <P>SOLUTION: In the screw press, a supply pipe 28 is connected to a screw shaft 6 having a raw liquid supply passage 8, the starting end portion of the supply pipe 28 is expanded to fix baffle plates 30 etc., the supply pipe 28 is brought into slidable contact with a flocculating pipe 31, an agitating vane 32 is disposed on the starting end wall portion of the flocculating pipe 31, and a sludge supply pipe 37 for raw liquid sludge and a chemical feed pipe 38 for a flocculant are connected to the peripheral wall. Combination of rapid agitation and the baffle plates in the small-diameter pipe eliminates uneven agitation to enable uniform floc formation. Dehydration carried out immediately after the floc formation eliminates destruction of flocs to increase drainability and improve dewaterability. The supply amount of the conditioned sludge can be increased at the same level as a screw press provided with a flocculating and mixing tank, which enables large-volume treatment by the scaling up of the screw press. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a screw press that adds a polymer to sludge generated from wastewater treatment facilities such as sewage, settlement drainage, human waste treatment, factory wastewater, etc., and in particular, installs a large coagulation and mixing tank in front of the screw press. The present invention relates to an improvement of a screw press in which a circular agglomeration device is connected to the screw press.

Conventionally, screw presses for dewatering sewage sludge have to be dewatered after flocculation with a polymer, and as shown in Fig. 6, agglomerated sludge obtained by stirring and mixing sludge and aggregating agent in a coagulation mixing tank is supplied to the screw press. is doing. For example, Patent Document 1 discloses a screw press in which a mixing tank is installed and granulated flocs suitable for dehydration are supplied. In addition, the rotating shaft around which the screw blade is wound is arranged inside the horizontal cylindrical main body, the overflow wall is erected inside the main body, the sludge supply pipe side is the sludge adjustment chamber, For example, Patent Document 2 discloses a sludge treatment apparatus provided with a stirring blade on a rotating shaft.
Japanese Patent No. 3679359 (paragraph number 0013, FIG. 1) Japanese Patent Publication No. 06-15116 (Claim 1, FIG. 1)

  Since a conventional mixing tank for agglomerating sewage sludge and the like with a polymer is relatively large, a space for installing and monitoring a large agglomeration mixing tank is required on the stock solution supply port side of the screw press. When it became a large dehydrator, the agglomeration mixing tank also became a large tank to maintain a predetermined residence time, and the peripheral speed of the stirrer was different between the central part and the peripheral part. . In addition, the sludge treatment equipment provided with a sludge adjustment chamber inside the horizontal cylindrical body eliminates the need for a coagulation mixing tank installation space and a monitoring space. In the granulation, since the rotation speed of the stirring blade is slow, the generation state varies. When the conditioning chamber is installed in a screw press and is pressed and dehydrated, there is a possibility that the aggregated flocs may be missed from the screen.

  The present invention provides a screw press having an agglomeration device in which a flocculent floc is generated by directly connecting a circular agglomeration device to a screw press by applying the technology of a line mixer.

  A screw press having a flocculation apparatus according to the present invention forms a filtration chamber with an outer cylinder screen and a screw shaft, supplies tempered sludge to the filtration chamber from a stock solution supply path installed in the screw shaft, and wraps around the screw shaft. Concentrated and dehydrated while transferring conditioned sludge with a screw blade, and a screw press that takes out the dehydrated cake from the discharge port, a circular agglomeration device communicating with the filtration chamber is connected to the screw shaft, and the start end wall portion of the agglomeration device In addition to the agitation device in the vicinity of the agitation blades, a sludge supply mud supply pipe and a flocculant chemical injection pipe are connected to the agglomeration device in the vicinity of the agitation blades. In addition, there is no breakage of flocs, drainage is improved, and dewaterability is improved. The amount of tempered sludge supplied to the filtration chamber of the screw press can be secured. A plurality of baffle plates are fixed to the inner peripheral wall on the sludge outlet side of the coagulator connected to the screw press, and the swirl flow that is stirred and mixed by the baffle plate is used as the baffle plate. It is possible to supply the filtration chamber with conditioned sludge that has been turbulent and collided to promote flocking, promotes flocking, and has an appropriate floc by the granulation effect due to the reduction in speed and has been rectified into a linear flow. There is no variation in aggregated flocs, and uniform flocs can be formed.

  A circular agglomeration device is composed of a supply pipe fixed to a screw shaft and an agglomeration pipe that is slidably contacted with the supply pipe. Can supply. Moreover, since stirring is performed in a tube having a small diameter, uneven stirring is eliminated. A stirrer blade is disposed on the starting wall of the agglomeration pipe, and the raw sludge supply pipe and the flocculant chemical injection pipe are connected to the agglomeration pipe near the agitation blade, and a plurality of baffle plates are fixed to the supply pipe. The swirl flow that has been stirred and mixed is made to collide with the baffle plate to be turbulent, promote flocking, and the turbulent flow can be rectified by the baffle plate. In addition, instead of the chemical injection pipe connected to the aggregation pipe, the chemical injection pipe may be connected to the mud supply pipe, which is suitable for a screw press with a small space for installing auxiliary equipment.

  Another invention of the flocculation device connected to the screw press is that the sludge feed pipe on the peripheral wall of the flocculation pipe is removed, a sludge inlet is expanded, and a line mixer is connected to the sludge inlet. Further, two-stage flocculation is possible, and sludge that is difficult to flocculate in one stage can be applied. Even if the supply amount of sludge is increased, there is no variation in the flocculation flocs, and a uniform floc can be formed. Two-stage agglomeration enhances the stirring power, enables large-capacity treatment, and allows expansion of applicable sludge and enlargement of the screw press.

The configuration of the line mixer consists of a stirring blade on the start wall and a plurality of baffle plates on the inner peripheral wall on the sludge outlet side, and a mud supply pipe connected to the line mixer near the stirring blade. By using two types of polymer flocculants or separate flocculants such as inorganic flocculants and polymer flocculants in the line mixer and the flocculant It is possible to form a strong and strong floc, and it can be applied to a higher range of sludge. There is no variation in aggregated flocs, it is possible to form uniform flocs, and it can be applied to hardly dewatered sludge and the like that require adjustment time. In addition, you may connect the chemical injection pipe connected to a mud pipe to the surrounding wall of a line mixer.

  The present invention is configured as described above, and by connecting a tubular agglomeration device to the inlet portion of the screw press, the shaft core of the screw shaft and the agglomeration device become common, and the diameter of the agglomeration device is small. Become. It is not necessary to install a large coagulation mixing tank on the stock solution supply side of the screw press, and the installation space for the coagulation device and the monitoring space are not required. If a line mixer and a coagulation chamber are connected, a large volume of coagulated sludge can be processed, and the size of the screw press can be increased. In addition, flock granulation can be promoted by a baffle plate that rotates with the screw shaft.

  An embodiment of the present invention will be described in detail with reference to the drawings. First, FIG. 1 is a longitudinal sectional view of a screw press having an aggregating device, and a screw press 3 supported on front and rear front frames 1 and 2 is as follows. An outer cylinder screen 4 having a screen stretched around its periphery and a screw shaft 6 around which screw blades 5 are wound are disposed. The screw shaft 6 is enlarged from the sludge supply side to the cake discharge side, and the filtration chamber 7 formed between the outer cylinder screen 4 and the screw shaft 6 has a volume as the condensed sludge is concentrated and dewatered. It has been reduced. An undiluted solution supply path 8 is inscribed in the screw shaft 6, and conditioned sludge is supplied from the supply hole 8 a to the filtration chamber 7.

  In the embodiment of the present invention, the cylindrical outer cylinder screen 4 is divided into an outer cylinder screen 4a in the first half of the concentration zone A and an outer cylinder screen 4b in the second half of the filtration / dehydration zone B. An intermediate bearing 9 is interposed between the outer cylinder screen 4 a and the outer cylinder screen 4 b in the filtration / dehydration zone B, and the lower part of the outer cylinder screen 4 b in the filtration / dehydration zone B is supported by an outer cylinder support roller 10.

  FIG. 2 is an enlarged view of a main part on the stock solution supply side of the screw press. A flange 11 connected to the supply side of the outer cylinder screen 4a in the concentration zone A is supported by a rotary plate bearing 12 provided on the front frame 1. is there. A sprocket 13 is fitted to the flange 11, and is interlocked and connected to a concentrating outer cylinder drive machine 14 that is placed on the mount 1 a of the front frame 1 and can be rotated forward and backward.

  FIG. 3 is an enlarged view of the main part of the dewatering cake discharge side of the screw press, and a rotating plate bearing 16 in which a rotating plate 15 connected to the discharging side of the outer cylinder screen 4b in the filtration / dehydration zone B is disposed on the rear frame 2. A sprocket 17 fitted to the rotary plate 15 is linked to a dehydrator outer cylinder drive 18 mounted on the rear frame 2. The outer cylinder screen 4a in the concentration zone A and the outer cylinder screen 4b in the filtration / dehydration zone B can be rotated at a differential speed. A screw drive shaft 19 is connected to a rear end portion of the screw shaft 6 provided in the outer cylinder screen 4b, and the screw drive shaft 19 is supported by a bearing 20 provided on the frame 2a of the rear frame 2. A sprocket 21 is fitted on the screw drive shaft 19 and is linked to a screw drive machine (not shown). A back pressure adjusting presser 23 supported on a presser moving shaft 22 is disposed on the rear end side of the filtration chamber 7, and the presser 23 is connected to a moving cylinder 24 supported on the rear frame 2. The cake outlet 25 of the chamber 7 can be adjusted.

  The screw shaft 6 is rotated while the outer cylinder screen 4a in the concentration zone A and the outer cylinder screen 4b in the filtration / dehydration zone B are rotated at a differential speed. The tempered sludge supplied to the filtration chamber 7 is transferred from the supply side to the cake discharge side by the screw blade 5, and the filtrate is separated from the outer cylinder screens 4 a and 4 b and disposed below the filtration chamber 7. The filtered trough 26 is discharged. The tempered sludge becomes cake while being concentrated and dehydrated, and is discharged from the cake outlet 25 to the cake outlet 27 while receiving back pressure by the presser 23.

  As shown in FIG. 2, a flocculent sludge supply pipe 28 is connected to the starting end of the screw shaft 6, and a bearing 29 is fitted to the outer periphery of the enlarged supply pipe 28 and connected to the outer cylinder 4 a. 11, the supply pipe 28 is rotatably supported together with the screw shaft 6. A plurality of baffle plates 30... Are radially attached to the inner peripheral surface of the supply pipe 28, and the supply pipe 28 is communicated with the filtration chamber 7 from the stock solution supply path 8 of the screw shaft 6. It is rotated together with the screw shaft 6.

  FIG. 4 is an enlarged view of the aggregating apparatus connected to the stock solution supply side of the screw press. A supply pipe 28 connected to the starting end of the screw shaft 6 is connected to an aggregation pipe 31 supported on the front frame 1 via a gland packing 33. Are in sliding contact. An agitation blade 32 is disposed on the starting end wall portion of the aggregating tube 31, is pivotally supported by a bearing 34 provided on the end wall, and is directly connected to an agitation drive unit 36 supported on a gantry 35 on the outer peripheral portion of the end wall. A sludge supply mud pipe 37 and a flocculant chemical injection pipe 38 are connected to the peripheral wall of the aggregation pipe 31, and the mud supply pipe 37 and the chemical injection pipe 38 are opened near the tip of the stirring blade 32. . The raw sludge supply mud pipe 37 and the flocculant chemical injection pipe 38 may be connected to the start wall of the aggregation pipe 31. A circular agglomeration device 39 forming a line mixer is constituted by a supply pipe 28 connected to the screw shaft 6 and rotating and an agglomeration pipe 31 slidably in contact with the supply pipe 28. By connecting the aggregating device 39 to the inlet of the screw press 3, the axis of the screw shaft 6 and the axis of the aggregating device 39 become common, and the coagulation floc can be smoothly pressed into the filtration chamber 7 without being destroyed. . There is no need to install a large agglomeration mixing tank on the stock solution supply side of the screw press 3, and the installation space for the conventional aggregating apparatus and the monitoring space become unnecessary.

  The number of rotations of the stirring blade 32 shown in FIG. 4 is appropriately changed according to the concentration of the stock solution and the type of the flocculant, and is 200 to 600 rpm per minute. The stock solution and the flocculant are pressed into the vicinity of the tip of the stirring blade 32, The sludge and the flocculant are rapidly stirred with the stirring blade 32. The swirl flow agitated and mixed by the agitation blades 32 collides with the baffle plates 30. The flocs are further granulated by the left and right baffle plates 30, 30 that rotate with the screw shaft 6. The tempered sludge in which the flocs are formed is caused to flow from the supply pipe 28 into the stock solution supply path 8 and supplied to the filtration chamber 7 of the screw press 3. Since stirring is performed by a combination of rapid stirring and a baffle plate in a pipe having a small diameter, there is no unevenness in stirring, and the flocs fluctuate and uniform flocs can be formed. Immediately after the formation of the floc, dewatering is performed, the floc is not destroyed, the water drainage is increased, and the dewaterability is improved. It is possible to increase the supply amount of tempered sludge equivalent to a screw press provided with a coagulation mixing tank, and a large-capacity treatment can be performed by increasing the size of the screw press. The plurality of baffle plates 30 fixed to the inner peripheral wall of the aggregation tube 31 may be extended to the vicinity of the axial center of the aggregation tube 31, and the turbulence of the water flow can be promoted. The chemical injection pipe 38 is not connected to the peripheral wall of the aggregation pipe 31, but the chemical injection pipe 38 is connected to the mud supply pipe 37, and the mixed solution of the stock solution and the coagulant is pressed into the vicinity of the tip of the stirring blade 32 from the mud supply pipe 37. You can do it.

  FIG. 5 shows another embodiment of the screw press having the aggregating apparatus, in which the sludge inlet of the aggregating apparatus shown in FIG. 4 is expanded and connected to the line mixer. A supply pipe 28 in which the sludge supply pipe 37 of the raw sludge connected to the peripheral wall of the aggregation pipe 31 shown in FIG. 4 is removed, and the aggregation pipe 40 having a structure in which the sludge inlet 40 a is expanded is connected to the start end of the screw shaft 6. The aggregating apparatus 41 is configured to be brought into sliding contact with each other to form a line mixer. A line mixer 42 is connected to the sludge inlet 40a of the agglomeration tube 40. A stirring blade 43 is pivotally supported by a bearing 44 provided on the end wall of the start end wall portion of the line mixer 42, and a frame 45 on the outer peripheral portion of the end wall is supported. It is directly connected to the agitation drive unit 46 supported on A plurality of baffle plates 47... Are radially attached to the inner peripheral wall of the line mixer 42 in the vicinity of the sludge inlet 40 a of the aggregation pipe 40, and a flocculant drug injection pipe 48 is connected to the peripheral wall of the line mixer 42. A mud pipe 49 is connected. The raw solution sludge mixed with the flocculant is pressed into the vicinity of the tip of the stirring blade 42. Note that the chemical injection pipe 48 may be connected to the peripheral wall of the line mixer 42 instead of being connected to the mud supply pipe 49.

  The number of revolutions of the stirring blade 43 of the line mixer 42 disposed in the preceding stage of the aggregating device 41 is also appropriately changed depending on the concentration of the stock solution and the type of the aggregating agent, and is 200 to 600 rpm per minute. The stock solution press-fitted into the line mixer 42 is rapidly stirred by the stirring blade 43, collides with the baffle plates 47, and is pressed into the vicinity of the tip of the stirring blade 32 of the aggregation tube 40 while promoting floc formation. Aggregated sludge during floc formation is rapidly agitated by the agitating blade 32 and divided, and the swirl flow that has been agitated and mixed is made to collide with the baffle plates 30. Strong flocks are granulated by colliding with the left and right baffle plates 30, 30 rotating together with the screw shaft 6. The tempered sludge in which the flocs are formed is caused to flow from the supply pipe 28 into the stock solution supply path 8 and supplied to the filtration chamber 7 of the screw press 3. Two-stage aggregation is performed by connecting the line mixer 42 and the aggregating device 41, and the aggregated floc can be subdivided to form a uniform strong floc. Even if the supply amount of sludge is increased, it can be applied to difficult-to-dehydrate sludge and the like that do not vary in flocs and require adjustment time. Large capacity treatment of the coagulated sludge becomes possible, and the size of the screw press 3 can be increased. The plurality of baffle plates 47... Fixed to the inner peripheral wall of the line mixer 42 may be extended to the vicinity of the axis of the line mixer 42, and can be made flocked.

About the screw press using the conventional type coagulation mixing tank shown in FIG. 6 and the line mixer direct connection type screw press shown in FIG. A comparative test was performed with 9% polymer flocculant added. The outer cylinder screen is stopped, the screw shaft is rotated at a rotation speed of 0.5 min ⁻¹ and a rotation speed of 1.0 min ⁻¹ , the cake moisture content (% WB), the processing amount (kg / h), and the recovery rate (%) Was measured. The results of the comparative test are shown in Table 1. The test results showed that the water content and the recovery rate were almost the same, but the treatment amount was 1.13 times and 1.10 times, respectively, when the rotational speed was 0.5 min ^-1 and the rotational speed was 1.0 min ^-1. The result was that the number of direct-type mixer-type screw presses was higher than that of screw presses using a type of coagulation mixing tank.

Next, a polymer flocculant with a chemical injection rate of 0.7% was added to mechanically concentrated mixed raw sludge having a concentration of 4.1% at the M purification center, and a comparative test was performed using the above screw press. Table 2 shows the results of a comparative test of water content (% WB), treatment amount (kg / h), and recovery rate (%). The test results showed that the moisture content and the recovery rate were almost the same, but the treatment amount was 1.16 times and 1.24 times, respectively, when the rotational speed was 0.5 min ⁻¹ and the rotational speed was 1.0 min ^−1. The result was that the number of direct-type mixer-type screw presses was higher than that of screw presses using a type of coagulation mixing tank.

  Table 3 is a graph showing the comparative test of Table 1 and Table 2. The vertical axis represents the throughput kg / h, and the horizontal axis represents the cake water content% W. B is shown. When these results are seen, the line mixer direct connection type screw press has the same or better result as compared with the screw press using the conventional type standard coagulation mixing tank. This is considered to be because floc formation at the time of tempering is properly performed, and concentration and dehydration is performed immediately after the floc formation, so that the floc is not destroyed.

  The screw press having the agglomeration apparatus of the present invention applies the technology of a line mixer and stirs and mixes in a small diameter tube by a combination of rapid stirring and a baffle plate. That is, a supply pipe having a plurality of baffle plates fixed to a screw shaft inscribed in the stock solution supply path is connected, and the aggregation pipe is slidably contacted with the supply pipe. A sludge supply pipe and a flocculant chemical injection pipe are connected to constitute a coagulation apparatus, and there is no unevenness in stirring, and a uniform floc can be formed. Immediately after the formation of the floc, dewatering is performed, the floc is not destroyed, the water drainage is increased, and the dewaterability is improved. It is possible to increase the supply amount of tempered sludge equivalent to that of a screw press provided with a coagulation mixing tank, and it can be applied to difficult-to-dehydrate sludge that requires adjustment time, and a large-capacity treatment can be performed by increasing the size of the screw press. It becomes an optimal screw press that adds a polymer to the sludge generated from wastewater treatment facilities such as sewage, settlement drainage, human waste treatment, and factory wastewater, and presses and dehydrates.

It is a longitudinal cross-sectional view of the screw press which has the aggregation apparatus which concerns on this invention. Similarly, it is a principal part enlarged view of the stock solution supply side of a screw press. Similarly, it is a principal part enlarged view of the dewatering cake discharge | emission side of a screw press. Similarly, it is an enlarged view of the aggregating apparatus connected to the stock solution supply side of the screw press. Similarly, it is the longitudinal cross-sectional view of the other Example of the screw press which has an aggregating apparatus. It is a conceptual diagram of the screw press using the conventional type coagulation mixing tank.

Explanation of symbols

4 Outer screen 5 Screw blade 6 Screw shaft 7 Filtration chamber 8 Stock solution supply path 25 Discharge port 28 Supply pipe 30, 47 Baffle plate 31, 40 Aggregation pipe 32, 43 Agitation blade 37, 49 Mud supply pipe 38, 48 39 41 Coagulator 40a Sludge inlet 42 Line mixer

Claims (8)

A filtration chamber (7) is formed by the outer cylinder screen (4) and the screw shaft (6), and conditioned sludge is supplied to the filtration chamber (7) from the raw solution supply path (8) installed in the screw shaft (6). In a screw press that removes the dehydrated cake from the discharge port (25) by transferring the conditioned sludge with the screw blade (5) wound around the screw shaft (6) and removing the dehydrated cake, the circle communicating with the filtration chamber (7) A tubular aggregating device (39) is connected to the screw shaft (6), a stirring blade (32) is disposed on the starting end wall of the aggregating device (39), and an aggregating device (39 near the stirring blade (32) is provided. A screw press having a flocculating apparatus, wherein a sludge supply pipe (37) for raw liquid sludge and a chemical injection pipe (38) for a flocculant are connected to each other. The screw press having the aggregating apparatus according to claim 1, wherein a plurality of baffle plates (30 ...) are fixed to an inner peripheral wall of the aggregating apparatus (39) on the sludge outlet side. The said aggregating apparatus (39) is comprised by the supply pipe | tube (28) fixed to the screw shaft (6), and the aggregation pipe | tube (31) slidably contacted with a supply pipe | tube (28), or characterized by the above-mentioned. A screw press having the aggregating apparatus according to 2. A stirring blade (32) is disposed on the starting end wall portion of the aggregating tube (31), and a raw sludge mud supply tube (37) and a flocculant chemical injection tube are disposed on the aggregating tube (31) in the vicinity of the agitating blade (32). The screw press having an aggregating apparatus according to claim 3, wherein (38) is connected and a plurality of baffle plates (30 ...) are fixed to the supply pipe (28). The screw press having the aggregating apparatus according to any one of claims 1 to 4, wherein a chemical injection pipe (38) connected to the aggregating pipe (31) is connected to a mud supply pipe (37). The mud pipe (37) on the peripheral wall of the coagulation pipe (31) is removed, and the coagulation pipe (40) is formed by expanding the sludge inlet (40a), and the line mixer (42) is connected to the sludge inlet (40a). A screw press having an aggregating apparatus according to claim 1, wherein: A stirring blade (43) is provided on the starting end wall of the line mixer (42), and a plurality of baffle plates (47...) Are provided on the inner peripheral wall on the sludge outlet side. The screw press having an aggregating apparatus according to claim 6, wherein a mud supply pipe (49) for connecting the chemical injection pipe (48) is connected to the mixer (42). The screw press having the agglomeration device according to claim 7, wherein a chemical injection pipe (48) connected to the mud supply pipe (49) is connected to a peripheral wall of the line mixer (42).