KR950005817Y1 - Sludge collecting apparatus of sedimentation tank - Google Patents

Abstract

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Description

Sludge Collection Device of Wastewater Treatment Plant

1 is a view schematically showing a sludge collecting device of a wastewater treatment apparatus that has been conventionally used.

2 is a plan view of the sedimentation basin is installed sludge collection apparatus according to a first embodiment of the present invention.

3 is a partially cutaway front view of the sedimentation basin shown in FIG.

Figure 4 is an enlarged view of the main portion of the sludge collecting device according to the present invention.

5 is a perspective view of a sludge suction header applied to the sludge collecting device of the present invention.

6 is a sectional view taken along line VI-VI in FIG.

7 is a front view of the free end of the sludge suction header shown in FIG.

8 is a plan view of the sedimentation basin is installed sludge collection apparatus according to a second embodiment of the present invention.

9 is a front view of the sedimentation basin shown in FIG.

10 is a plan view of the sedimentation basin is installed sludge collection apparatus according to a third embodiment of the present invention.

11 is a front view of the sedimentation basin shown in FIG.

12 is a partially cutaway plan view showing a second embodiment of the sludge collection header according to the present invention.

FIG. 13 is a side view of the sludge collecting header shown in FIG.

14 is a front view of the free end of the sludge collecting header shown in FIG.

* Explanation of symbols for main parts of the drawings

30: sedimentation basin 36: drainage passage

42: wastewater supply pipe 46: sludge discharge conduit

50: bridge 52: drive device

56: drive cage 60: header

70: orifice 88: manifold

The present invention relates to a sludge removal facility of a wastewater treatment plant, and more particularly, to a sludge collection device configured to collect sludge in the final settler of the sludge removal facility, some of which are returned to the aeration tank, and others are dewatered and disposed of.

In general, the wastewater treatment apparatus is equipped with various types of sludge removal facilities for collecting and removing sludge mixed in the water, and the conventional sludge removal facilities are shown in FIG. It consists of settling basin.

In the initial settler, sludge is removed mechanically or physically from highly contaminated influent wastewater with a biological oxygen demand (BOD) of 200 ppm or more, where the sludge removed first is completely decomposed in a digester not shown. And then disposed of. Since the amount of sludge removed first from the initial settler is only about 30% of the total, the biological oxygen demand of the wastewater supplied to the aeration tank is still maintained at a high level, for example, 140 ppm or more.

In aeration tanks, sludge is biodegraded using aerobic microorganisms that produce less odors. In order to activate the sludge decomposition of microorganisms, it is necessary to continuously supply a large amount of air into the aeration tank and to supply external microorganisms into the aeration tank. The sludge takes about 3 hours to be decomposed by microorganisms, and the wastewater in the sludge decomposed aeration tank flows into the final settler.

In the final settler, the sludge is removed in a mechanical or physical manner as in the initial settler described above. That is, the sludge precipitated at the bottom of the final settler is discharged to the outside by the sludge collecting device, and then some of them are returned to the aeration tank, and the rest is disposed of after dehydration. The reason for returning some of the sludge of the final settler to the aeration tank is to promote biodegradation by supplying microorganisms of the final settler in the propagation state into the aeration tank. The biological oxygen demand of the effluent discharged to the stream through the final settler is kept below 20 ppm.

As schematically shown in FIG. 1, the conventional sludge collecting device used in the final settler is a so-called "scraper type", which is installed at the center of the settling basin 10 and rotated by a driving device. And a horizontal beam or truss 14 extending radially from the lower end of the vertical axis 12 and a plurality of scraper blades 16 inclined at regular intervals along the longitudinal direction of the truss 14. It consists of. When the sludge collecting device of this configuration starts to operate and a clockwise rotational movement is caused on the vertical axis 12 and the horizontal truss 14, the scraper blade 16 gradually scrapes the sludge accumulated at the bottom of the sedimentation basin. The sludge collected at the center is discharged out of the sedimentation basin by the sludge pump or the sludge valve through the main pipe 18. Some of the sludge from the main pipe 18 is removed through the first branch pipe 20, while the remainder is conveyed to the aeration tank via the second branch pipe 22. Since a large amount of microorganisms survive in the sludge returned to the aeration tank, sludge decomposition in the aeration tank can be promoted.

However, the conventional scraper type sludge collection device as described above is very slow in sludge collection rate, and it takes several hours only to collect the sludge existing near the side wall of the sedimentation basin.

Therefore, during the collection of the sludge, the microorganisms living therein become apnea, which lowers the activity of the sludge, not only does not increase the concentration of microorganisms in the sludge returned to the aeration tank, but also increases the emission of phosphate, one of the pollutants. do. Under these conditions, to maintain a sludge decomposition capacity of the aeration tank is to increase the amount of air supply, proportionately increases the energy consumption and operating cost of the aeration tank. In addition, in the scraper type sludge collection apparatus, the sludge layer is disturbed by the scraper blades, so that a light solid matter floats and the concentration of sludge to be collected is low. Therefore, it is impossible to improve the overall sludge collection efficiency beyond a certain limit. Moreover, in order to install the scraper type sludge collection device, the bottom surface of the sedimentation basin must be conical, so construction is very difficult and the main cause of mechanical failure, and much effort and cost are required for the maintenance and repair of the scraper.

Therefore, the object of the present invention is to collect the sludge accumulated in the bottom of the sedimentation basin in a short time without disturbing, and to reduce the air supply amount and sludge return to the aeration tank by returning the sludge with high survival rate of microorganisms to the aeration tank. In addition, the present invention provides a sludge collection device for final sedimentation of a wastewater treatment plant that can be easily applied to a sedimentation basin having a flat bottom surface and has low maintenance and repair costs.

The purpose of the present invention is to collect the sludge containing microorganisms from the wastewater flowing into the circular final settler from the aeration tank of the wastewater treatment apparatus, some of which are returned to the aeration tank and the other is discharged to an external sludge treatment facility. A sludge collection device for; A driving means detachably installed on a bridge across the upper portion of the settling basin and having an output shaft coinciding with the center of the settling basin; A drive cage fixed to the output shaft of the drive means and extending vertically in a predetermined length toward the bottom of the sedimentation basin, and having a manifold attached to the bottom of the sedimentation basin; It extends radially outward from the manifold of the drive cage toward the side wall of the sedimentation basin, and a plurality of orifices are disposed on the front surface at regular intervals in the longitudinal direction, and the sludge suctioned from the bottom surface of the sedimentation basin is driven. At least one single tubular header designed to guide the manifold of the cage; The sludge collection device of the wastewater treatment plant, which is in fluid communication with the header through the manifold and consists of a discharge conduit for discharging the sludge sucked through the orifice of the header out of the sedimentation basin.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 2 to 11 of the accompanying drawings.

First, referring to FIGS. 2 and 3, the sedimentation basin in which the sludge collection device of the first embodiment according to the present invention is installed is shown as a plan view and a front view, respectively. The sedimentation basin 30 is a circular water tank made of a concrete structure or the like, which has a substantially flat bottom wall 32, a cylindrical sidewall 34 standing vertically upward from the edge of the bottom wall 32, and the bottom wall ( And a drain passage 36 disposed in an annular shape along the inner surface of the side wall 34 at an appropriate height from the bottom surface 32. At the bottom of the drain passage 36, the purified water discharge pipe 38 is installed in an L-shape through the side wall, and the water flowing into the drain passage 36 at the center of the settling basin 30 passes through the purified water discharge pipe 38. It is discharged to outside rivers through. The bottom wall 32 of the sedimentation basin 30 may be a completely flat horizontal surface, but in order to increase the collection efficiency of the sludge, a slight gradient toward the center of the sedimentation basin 30, for example, a grade of 2/100 to 5/100 It is preferable to put. The upper end of the settling basin 30 is provided with an air permeable cover 39 made of a fabric or a net. The reason why the cover 39 is installed is to prevent invasion of the foreign matter, for example, the inside of the sedimentation basin 30 such as a piece of vinyl. If the cover 39 is not provided, a problem may occur in the operation of the sludge collecting device because the orifice of the header, which will be described later, is blocked by foreign matter.

In the center of the sedimentation basin 30, the central column 40 for inflow of wastewater extends vertically upward through the bottom wall 32. The lower end of the central column 40 is an aeration tank (see FIG. 1). And a wastewater discharge port 44 for discharging the wastewater into the sedimentation basin 30 at its upper end is formed radially. Therefore, the wastewater supplied from the aeration tank flows into the sedimentation basin 30 through the wastewater discharge port 44 of the central column 40, as indicated by arrows in FIG. 3, and then precipitates the sludge and then drains 36. It is overflowed with and discharged to the outside. In addition, a sludge discharge conduit 46 is provided on the bottom wall 32 of the sedimentation basin 30 adjacent to the central column 40. The inlet end of the sludge discharge conduit 46 is fluidly connected to the manifold of the sludge collecting device, which will be described later in detail, while its outlet end is via a sludge pump or a sludge discharge valve (not shown). Connected to the aeration tank. On the other hand, a float collecting trough 48 is disposed at an appropriate position of the side wall 34 of the settling basin 30, and the upper surface of the trough 48 is designed to substantially coincide with the surface of the settling basin 30. As shown in FIG. As will be described in detail later, the trough 48 performs a function of vertically and removing various floats floating on the surface of the sedimentation basin 30 in cooperation with the float collection device forming a part of the sludge collecting device.

The bridge 50 is installed across the center of the settling basin 30 from the top of the side wall 34 of the settling basin 30. 2 and 3, the bridge 50 is shown to extend only to the center of the settling basin 30, but of course the length may be increased to reach the side wall of the opposite side. Since the bridge 50 is a passage through which a manager, a repairman, and the like of the wastewater treatment plant can approach the center of the sedimentation basin 30, a sufficient area and space necessary for the inspection and repair of the sludge collection device must be secured, and it may occur during maintenance. It is to be designed in consideration of the maximum load present, and it is necessary to install guide rails on both handrails.

In the appropriate place of the bridge 50 corresponding to the center of the settling basin 30, a conventional drive device 52 made of a drive motor, a reducer, a torque limiter, and the like are provided. The drive device 52 should have a high reduction ratio of, for example, about 1/10930, and is preferably housed in a hermetic housing in consideration of being installed outdoors. This drive 52 has an output shaft 54 oriented downward, the center of rotation of which is substantially coincident with the center of the settling basin 30.

A drive cage 56 made of steel structure or the like is attached to the output shaft 54 of the drive device 52 so as to extend vertically with a predetermined length toward the bottom of the settling basin. In addition, the drive carriage 56 has a sealed manifold 58 at its lower end, and the manifold 58 is in fluid communication with a single tubular header 60 which describes the sludge discharge conduit 46 described later. Play a role of 4 shows the enclosed minifold 58 and its surrounding structures in detail. As shown, the manifold 58 has a substantially trapezoidal cross-sectional shape, and a lower end portion thereof has a sealing ring 62 made of an elastic material such as rubber or the like. Since the sealing ring 62 is continuously connected to the bottom surface 32 of the sedimentation basin 30 even though the manifold 58 rotates together with the drive cage 56, the sealing ring 62 maintains a sealing state. Is delivered to the single tubular header 60 through the manifold 58 to allow suction and discharge of sludge. Of course, the upper end of the manifold 58 connected to the drive cage 56 must also be in liquid contact with the central column 40, otherwise the sealing in the manifold 58 will not be made, which will interfere with the sludge suction. do.

2 and 3 again, the single tubular header 60 extends radially outward from the manifold 58 of the drive cage 56 described above towards the side wall 34 of the settling basin 30. It can be seen that.

Since the header 60 has a cantilever structure with a length of about 15 m, the header 60 may be cracked at the connection between the manifold 5 and the header 60 unless it is supported by a separate reinforcement structure. . In the embodiment shown in Figs. 2 and 3, the truss 62 is used as the reinforcing structure, but other structures such as tie rods or the like may be used. If the header 60 is made of high strength metal and firmly attached to the manifold 58, the reinforcing structure such as the truss 62 may be omitted, and the reinforcing structure may be omitted from the viewpoint of preventing disturbance of the sludge layer. Ideally, use a missing header. In addition, the deflection angle of the header 60, that is, the relative angle of the header 60 with respect to the bottom wall 32 of the settling basin 30 is preferably adjustable to some extent.

As clearly shown in Figs. 5 and 6, the single tubular header 60 has a rhombic cross-sectional shape with front, back, top and bottom edges, and the tweezers from the proximal end toward the free end. Spread out Thus, the cross-sectional area of the header 60 is largest at the proximal end and smallest at the free end. The reason for the tapered design of the header 60 is to consider that the header 60 has a small angular velocity at the proximal end, the largest at the free end, and the disturbance of the sludge layer is also the greatest at the free end.

The header 60 also has a flange 64 formed longitudinally along its lower edge, the flange 64 having an elastic blade 66 having a length approximately equal to the length of the header 60 bolt / Removably attached by fastening means, such as the nut 68 and the like. However, in the present invention, the elastic blade 66 is not an indispensable component of the price, even if omitted, the operation of the sludge collecting device does not cause any problem, only the sludge collecting efficiency may be slightly reduced.

A plurality of orifices 70 are disposed along the longitudinal direction of the header 60 at regular intervals on the front lower inclined surface of the header 60. The orifice 70 is preferably designed such that its diameter increases gradually as it approaches the free end of the header 60. In the case of the header 60 having a length of about 15 m, the sludge collection efficiency can be maximized by setting the diameter of the orifice adjacent to the proximal end to 50 mm, the diameter of the orifice adjacent to the free end to 75 mm and the spacing between the orifices to be less than 760 mm. have. As described above, the purpose of gradually increasing the diameter of the orifice 70 toward the free end of the header 60 is that the negative pressure due to the pump or the hydraulic pressure is uniformly applied over the entire length of the header 60 so that the bottom of the sedimentation basin 30 is reduced. This is to allow for a balanced collection of sludge that has accumulated in the building. As can be seen from FIG. 7, a relatively large end orifice 71 is formed at the free end of the header 60. The end orifice 71 is formed by the sludge existing between the free end of the header 60 and the side wall 34 of the settling basin 30 during the process of collecting the sludge while the header 60 rotates at a predetermined speed. The strong suction acts to maximize the sludge collection efficiency.

2 and 3 again, on the opposite side of the header 60, it can be seen that a float collecting device 72 is provided for removing the float floating on the surface of the sedimentation basin. The float collecting device 72 includes a truss-shaped horizontal support 74 extending radially outward from the drive cage 56 toward the side wall 34 of the settling basin 30, and a free end of the horizontal support 74. It consists of a vertical support 76 extending upward in the vicinity and a float collecting blade 78 attached to the upper end of the vertical support 76 and in contact with the water surface of the settling basin. The operation of the floating matter collection device 72 will be described later.

Referring to Figures 2 and 3 will be described the operation of the sludge collection apparatus according to the present invention. First, when the output shaft 54 and the drive cage 56 start to rotate in response to the start of the drive device 52, the header 60 is clockwise in a predetermined speed, for example, 0.03 to 0.04 ppm. It will rotate at speed. At this time, since the negative pressure is acting on the header 60 by a vacuum pump or a siphon device, the sludge accumulated at the bottom of the settling basin 30 is caught by the front lower and lower inclined surfaces of the header and the blades 66 to open the orifice 70. Suction through and then discharged to the sludge discharge conduit 46 via the manifold (58). Some of this discharged sludge is returned to the aeration tank to be used for biodegradation of the solid material, and the rest is disposed of through the dehydration process.

In order to increase the survival rate of the microorganisms present in the conveying sludge, the header 60 is preferably rotated once in 25 to 35 minutes. However, if the rotation speed of the header 60 is excessively increased, care should be taken because the sludge layer may be disturbed near the free end of the header 60 having a relatively high angular speed. According to the experimental results, the speed of the free end of the header 60 should not be exceeded 4.5m / min and proved to be desirable to be maintained at 3.6m / min.

On the other hand, the float collecting device 72 installed on the opposite side of the header 60 collects the float while rotating at the same angular speed as the header 60.

That is, the blade 78 of the float collecting device 72 collects the float while rotating in contact with the surface of the sedimentation basin 30, and then discharges it to the outside through the float collecting trough 48. Therefore, according to the present invention, it is possible to prevent the floating of the sedimentation basin 30 to flow into the drainage passage 36 and flow into the stream, and to remove the sludge at the bottom of the sedimentation basin and the surface of the sedimentation basin simultaneously. can do.

8 and 9, the sludge collecting device according to the second embodiment of the present invention is shown as a plan view and a partially cutaway front view.

The sludge collecting device of this embodiment is distinguished from the sludge collecting device of FIGS. 2 and 3 in that it has a second header 80 provided at an angular position spaced 180 degrees with respect to the first header 60. do. When sludge is collected using the two headers 60 and 80 in this manner, the sludge collection amount does not change even if the rotational speed is reduced to 1/2.

On the other hand, if the rotational speed of the header (60) (80) is reduced to 1/2, the possibility of disturbance of the sludge layer is also reduced in proportion, thereby improving the overall sludge collection efficiency. Since the structure and arrangement of the other parts except for the headers 60 and 80 are the same as those described above with reference to FIGS. 2 and 3, only the reference numerals will be omitted and detailed description thereof will be omitted.

10 and 11, the sludge collecting device according to the third embodiment of the present invention is shown as a top view and a partially cutaway front view. The sludge collecting device of this embodiment is provided with a scraper 82 at an angular position 180 ° away from the header 60, and the header 60 is held horizontally by tie bars 84 instead of trusses. In this respect, it is distinguished from the sludge collection apparatus of the first and second embodiments.

Since the structure and operating principle of the scraper 82 is known in the art, no detailed description thereof will be required. In the sludge collecting device in which the header 60 and the scraper 84 are combined in this manner, the circumferential speed of the scraper 84 should be limited to a predetermined speed or less so that the sludge layer is not disturbed during the operation of the device. The sludge can be collected at a much higher speed than the conventional sludge collecting apparatus using only the fur 84 alone. Since the structure of the other components is the same as that of the first and second embodiments described above, only the reference numerals will be omitted, and detailed description thereof will be omitted.

12 to 13, it can be seen that the second embodiment of the sludge collecting header that can be applied to the sludge collecting apparatus of the various embodiments described above is shown. The header 86 of the second embodiment is provided with a flexible tube 88 attached to its free end and a roller 90 rotatably provided at the tip of the flexible tube 88. The expansion pipe 88 is made of, for example, bellows, etc., and can be freely shrunk or extended depending on the amount of pressure applied thereto, and has an orifice 92 for sucking sludge. The roller 90 rotates in contact with the side wall 34 of the sedimentation basin, and is always pressed toward the side wall 34 by the elasticity of the flexible tube 88.

Therefore, even if the side wall 34 of the settling basin is not constructed as a power source or if there are irregularities on its surface, the roller 90 is always in contact with the side wall 34 of the settling basin. In addition, an expansion blade 94 is attached to the lower portion of the expansion pipe 88 to scrape the sludge present near the free end of the header 86. It is preferable to guide the roller 90 by installing a guide rail 96 on the side wall 34 of the settling basin as shown in FIGS. 12 and 13, but in the present invention, the guide rail 96 is essential. no.

The sludge collection device of the present invention described in detail above can collect and remove sludge at the bottom of the sedimentation basin without disturbing in a short time, and can transport the sludge of high concentration with high survival rate of microorganisms to the aeration tank, and breaks down even after long time operation. It provides an extremely useful effect in the industry that there is little possibility of, and maintenance and repair cost is low.

Claims (8)

A sludge collection device for collecting sludge containing microorganisms from the wastewater flowing into the final settler from the aeration tank of the wastewater treatment plant, part of which is returned to the aeration tank and the other is discharged to an external sludge treatment facility; A cover 39 installed on an upper portion of the sedimentation basin 30 so as to prevent foreign substances from entering the sedimentation basin; A driving means 52 detachably installed on a bridge across the upper portion of the settling basin, the driving means 52 having an output shaft coinciding with the center of the settling basin; A drive cage 56 fixed to an output shaft of the drive means 52 and extending vertically to a bottom of the settling basin 30 at a predetermined length, and having a manifold in contact with a bottom surface of the settling basin; Wow; As extending radially outward from the manifold 58 of the drive cage 56 toward the side wall of the sedimentation basin 30, a plurality of orifices 70 are arranged on the front surface at regular intervals in the longitudinal direction, At the free end, a large orifice 71 is formed toward the side wall of the settling basin, and at least one single designed to guide the sludge suctioned from the bottom surface of the settling basin to the manifold 58 of the drive cage 56. A tubular header 60; The waste water treatment apparatus, which is in fluid communication with the header 60 through the manifold 58, comprises a discharge conduit 46 for discharging the sludge sucked through the orifice of the header 60 out of the sedimentation basin. Sludge collector. 2. The horizontal support of claim 1, further comprising a float collecting device (72) for removing float floating on the surface of the settling basin, wherein the floating collecting device (72) extends radially outward from the drive cage (56). 74, a vertical support 76 extending upward near the free end of the horizontal support 74, and a float collecting blade attached to an upper end of the vertical support 76 to rotate in contact with the surface of the settling basin. Sludge collection device, characterized in that consisting of (78). 3. The sludge collection device according to claim 2, wherein the float collecting device is installed at a position 180 ° away from the header. 2. The sludge collection apparatus of claim 1, wherein the header has a substantially rhombic cross section and one of its edges is adjacent to the bottom wall of the settling basin. 5. The sludge collection apparatus according to claim 4, wherein an elastic blade (66) having a predetermined length and width is attached to the corner of the header (60) proximate to the bottom surface of the settling basin in contact with the bottom wall. The sludge collection apparatus according to claim 1 or 5, wherein the orifice (70) formed on the front surface of the header (60) gradually increases in diameter from the proximal end to the free end of the header. 7. The sludge collection apparatus according to claim 6, wherein the cross-sectional area of the header (60) gradually decreases from the proximal end to the free end. 2. The roller 90 according to claim 1, wherein the free end of the header 60 is provided with a flexible tube 88, and the tip of the flexible tube 88 elastically contacts the side wall of the settling basin 30. Sludge collection device, characterized in that is installed.