JP5204449B2 - Scum remover - Google Patents

Description

  The present invention relates to a scum removing device that can efficiently remove scum generated on the water surface of a reaction tank of a sewage treatment plant.

  Conventionally, as a treatment method of sewage, as shown in Patent Document 1, the raw water is stirred in an anaerobic state or an oxygen-free state without dissolved oxygen without blowing air in the previous stage of the aeration zone, so that the sewage is more highly purified. A system has been developed and is in use.

However, in a reaction tank in an anaerobic state or an oxygen-free state, bubbles accompanied with sludge called scum are generated on the water surface, causing various problems. That is, since this scum is sludge with CO ₂ gas floating, if left as it is, the sludge hardens and the entire surface of the tank is covered with a thick scum layer, and the state of the treated water is changed. There were problems such as being unable to visually check, causing odor when left for a long period of time, causing stickiness to become debris and hindering defoaming by watering, and deteriorating aesthetics. .
The aerobic tank and anaerobic tank, and the anaerobic tank and anoxic tank partition walls are separated from each other to prevent the flow of dissolved oxygen and liquid mixture, and the treated water flows through the lower part of the partition walls. Since there is no place for the scum generated on the water surface to flow out, the scum was more likely to stay on the water surface of the reaction tank.

Therefore, until now, as a scum removal method, the scum is aerated by sprinkling water on the scum that has just occurred and defoaming, or by temporarily opening a weir plate near the water surface provided in the partition wall with the downstream tank. It was dealt with by measures such as pouring into the tank side, but it was forced to do extra work and inferior in workability, and constantly watering was a waste of water resources and energy, Since the work of pouring scum into the aeration tank is performed manually, the number of personnel is increased, and there is a problem that the processing efficiency is lowered due to temporary circulation.
Japanese Patent No. 2912905

  The present invention solves the above-described problems, and can remove scum generated on the water surface automatically and efficiently continuously and at low cost without generating extra work and personnel. The present invention has been completed for the purpose of providing a removal device.

The scum removing device of the present invention made to solve the above problems is a scum removing device provided with a defoaming device operating along with the rotating shaft on the water surface of the rotating shaft installed in the reaction tank, The defoaming device is composed of a winding blade whose center is fixed to a rotating shaft and has a spiral shape in plan view, and the scum that floats near the rotating shaft by the rotation of the winding blade is rolled into the liquid and removed. The lower part of the rotating shaft is composed of an upper blade for generating a lateral flow and a lower blade for generating a downward flow, and is provided with a stirring blade for stirring the bottom of the reaction vessel.

In the invention according to claim 1, since the defoaming device that operates together with the rotating shaft is provided on the water surface of the rotating shaft installed in the reaction vessel, the defoaming device automatically operates along with the rotation of the rotating shaft. Thus, the scum floating around the rotating shaft can be removed. In addition, the defoaming device is composed of a winding blade whose center is fixed to a rotating shaft and has a spiral shape in a plan view, and the scum that floats near the rotating shaft is rolled into and removed by the rotation of the winding blade. Therefore, the scum floating around the rotating shaft can be removed by automatically rotating the entrainment blade as the stirring blade rotates. Further, the bottom of the reaction tank is provided with a two-stage stirring blade for stirring the bottom of the reaction tank, comprising an upper blade for generating a lateral flow and a lower blade for generating a downward flow at the lower part of the rotating shaft. As a result, the removal of nitrogen and phosphorus in the raw water is promoted, the generation of filamentous fungi is suppressed, and the sedimentation property of the sludge can be stabilized.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic overall view showing a treatment tank for advanced treatment of raw water such as sewage. The treatment tank 1 is a deep tank type having a width and depth of about 10 m and a length of about 50 m. In order to perform advanced treatment, the anaerobic zone B in which the front stage of the treatment tank 1 is in an anaerobic state, dissolved oxygen This is an anoxic zone C in a state where there is no state. A is an aeration zone. The anaerobic zone B and the oxygen-free zone C are separated from each other by the partition wall 2, and the oxygen-free zone C and the aeration zone A are separated from each other by the partition wall 3.
As shown in FIG. 1, a circulation path 20 is connected to feed back a portion of treated water aerated and nitrified in the aeration zone A to the anoxic zone C as a nitrification liquid, thereby denitrifying. Is configured to be performed.

  A baffle plate (not shown) is vertically provided at the center in the width direction of the aeration zone A, and an air diffuser 4 is installed in the intermediate water depth of the one-side flow path for aeration in the middle stage. Thus, it has a structure that creates a flow that swirls up and down on both sides of the baffle plate. In addition, the said air diffusing device 4 is mounted, for example, on a beam (not shown) installed at intervals of 2 to 3 m.

In the anaerobic zone B and the oxygen-free zone C, a stirring blade 5 is provided at the center of the bottom surface of each zone. This stirring blade 5 is installed for the purpose of stirring the sludge so as to promote the removal of nitrogen and phosphorus in the raw water and to stabilize the sludge sedimentation by suppressing the generation of filamentous fungi. It is.
As shown in FIG. 2, the stirring blade 5 is a two-stage blade composed of a substantially straight upper blade 5a for generating a lateral flow and a substantially straight lower blade 5b for generating a downward flow. By attaching the step blades to the tip of the rotating shaft 6, sludge is not deposited on the bottom.

Moreover, the motor 7 which is a drive source of the stirring blade 5 is installed outside the upper surface of the tank body 1 and allows the stirring blade 5 to freely rotate normally, intermittently, decelerate and reversely rotate. As described above, since the motor 7 is outside the tank, maintenance management is easy, and if the motor 7 is periodically reversely rotated, the deposits attached to the blades can be easily peeled off.
Further, since the stirring blade 5 is attached to the tip of one long rotating shaft 6, it may be shaken by a swirling flow of sewage. In this case, the tip of the rotating shaft 6 is interposed via a steady-state member 9. If the structure is fixed to the bottom surface of the tank body 1, the rotating shaft 6 is firmly fixed and is not curved, and the stirring blade 5 is prevented from being shaken, so that the mixed liquid can be stirred efficiently.

The embodiment has a structure in which a defoaming device 8 for removing scum that operates together with the rotating shaft 6 is provided on the water surface of the rotating shaft 6 of the stirring blade 5.
As shown in FIGS. 3 to 4, the defoaming device 8 includes a winding blade 10 whose center is fixed to the rotating shaft 6 and has a spiral shape in plan view, and is floated near the rotating shaft by the rotation of the winding blade 10. The scum S to be rolled is taken into the liquid and removed.
That is, since the scum S floating on the liquid surface naturally gathers in the direction of the rotation axis as the rotation shaft 6 rotates, when the spiral entrainment blade 10 is rotated together with the rotation shaft 6, the scum S is entrained. While being guided by the blade 10 and further toward the center, it is drawn into the water. Thereafter, the scum S is finally released at a deep location in the liquid, and the stirring disappears in the liquid.
In this way, the spiral entrainment blade 10 rotates simultaneously with the rotation of the rotating shaft 6, whereby the scum S floating near the rotating shaft is naturally caught in the liquid and removed, which is efficient. Therefore, the scum can be removed. As shown in the figure, if the entrainment blade 10 is formed of blades inclined so as to gradually expand downward, the scum S is forcibly pushed down by the blades, so that it is more efficient. It is preferable because scum can be removed well.

Thus, according to the present invention, the water surface portion of the rotating shaft of the stirring blade is provided with a defoaming device that operates together with the rotating shaft, so that it floats on the liquid surface while performing normal operation. The scum can be removed automatically and efficiently at a low cost. Furthermore, since a stirring blade comprising an upper blade for generating a lateral flow and a lower blade for generating a downward flow is provided at the lower part of the rotating shaft, it is possible to prevent sludge from accumulating at the bottom of the reaction tank. The removal of nitrogen and phosphorus in the raw water is promoted, and the generation of filamentous fungi is suppressed, so that the sedimentation property of sludge can be stabilized.

It is a schematic whole view which shows a processing tank. It is a perspective view which shows the lower part of a stirring blade. It is a front view which shows the water surface part of a stirring blade. It is a top view which shows the water surface part of a stirring blade.

DESCRIPTION OF SYMBOLS 1 Processing tank 2 Partition 3 Partition 4 Aeration apparatus 5 Stirring blade 6 Rotating shaft 7 Motor 8 Defoaming device 9 Stabilizing member 10 Entrainment blade
20 circuit S Scum

Claims (1)

A scum removing device provided with a defoaming device that operates together with the rotating shaft on the water surface portion of the rotating shaft installed in the reaction tank, the defoaming device being fixed at the center to the rotating shaft and swirling in plan view The scum that floats in the vicinity of the rotation shaft by the rotation of the wrapping blade is entrapped and removed in the liquid, and the lower blade of the rotation shaft has an upper blade for generating a lateral flow and a downward direction. A scum removing device comprising a lower blade for generating a flow and provided with a stirring blade for stirring the bottom of the reaction vessel.

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