JP2010036078A - Method for driving rotary drum type sludge concentration device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for driving a rotary drum type sludge concentration device which can reduce the load of returned water and the output of an electric motor. <P>SOLUTION: The water pressure of cleaning water jetted for cleaning a drum screen 3 is set to low cleaning water pressure lower than the standard water pressure and to high cleaning water pressure higher than the standard water pressure, and the rotary drum type sludge concentration device 1 is driven in such a manner that the cleaning water is usually jetted at the low cleaning water pressure, and the water pressure of the cleaning water is switched from the low cleaning water pressure into the high cleaning water pressure every fixed time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for operating a rotary drum type sludge concentrating apparatus that separates and removes solid matter from sewage sludge and the like and concentrates it.

  As an important process for treating sewage sludge and the like, there is a sludge concentration step. This concentration step concentrates the low-concentration sludge generated in the water treatment facility by solid-liquid separation, thereby reducing the amount of the treated sludge and effectively making the subsequent dewatering step function. By efficiently concentrating such sludge, it is possible to reduce the size of the dehydrator and improve the dewatering performance.

  By the way, for example, as a sludge concentrator used in a sewage sludge concentration step, a centrifugal concentrator that performs solid-liquid separation using centrifugal force is known. However, this centrifugal concentrator has the disadvantages that the electric power consumed by the electric motor is large and the maintenance cost such as overhaul is high. On the other hand, the rotary drum type sludge concentrator (rotary drum type concentrator) has 1) low power consumption and low electricity cost 2) simple concentration mechanism and low maintenance cost 3) It can be processed from a small-scale capacity to a large-scale capacity. 4) It is compact and has a small installation space (see Patent Documents 1 to 3).

JP-A-2005-193105 JP 2007-330920 A JP 2008-18359 A

  Next, a conventional rotary drum type sludge concentrating device will be described with reference to FIG. 1 showing an embodiment of the present invention. As for the hardware configuration of the apparatus, the apparatus according to the present invention is basically not different from the conventional apparatus.

  A conventional rotating drum type sludge concentrating device (hereinafter referred to as “sludge concentrating device”) 1 is a main body frame 2 and a cylindrical screen (hereinafter referred to as “drum screen”) that is rotated around a horizontal axis within a casing. ) 3 is provided. Here, the drum screen 3 is rotationally driven by a drum electric motor 4 that rotates rotation support portions provided on the front, rear, left, and right sides using a transmission means such as a pulley to support the drum screen 3.

  A separation liquid receiver 5 is provided below the drum screen 3, and a discharge end of the separation liquid receiver 5 is connected to a separation liquid discharge pipe 6. Also, a sludge inlet tube 8 is disposed at the sludge inlet 7 on one end side of the casing that supports the drum screen 3, while a solid discharge chute 10 communicated with the sludge outlet 9 is provided on the other end side of the casing. The solid matter (sludge) after being attached and separating the separation liquid is discharged from the solid matter discharge chute 10 through the sludge discharge port 9.

  The drum screen 3 has a configuration in which metal wedge wires are arranged in parallel to each other in the horizontal rotation axis direction with a predetermined interval between them, and are formed in a cylindrical shape as a whole. Here, the appropriate mesh width of the drum screen 3 varies depending on the properties of the object to be processed, but is about 0.15 to 0.5 mm when sewage sludge is targeted.

  A spiral sludge transport guide member 11 is provided on the inner peripheral surface of the drum screen 3 from the sludge inlet 7 on one end side toward the sludge outlet 9 on the other end side.

  In the treatment of sludge, a polymer flocculant is added to the sludge to be concentrated, flocked in a flocculent mixing tank, and the flocified sludge is put into the drum screen 3 through the sludge inlet pipe 8. The sludge is transported to the outlet side while being separated into solid and liquid along the sludge transport guide member 11 as the drum screen 3 rotates. At this time, the floc sludge remains on the drum screen 3, and the liquid content in the sludge is filtered from the drainage part formed between the wedge wires of the drum screen 3, and the sludge is concentrated. The filtered liquid is discharged through the liquid receiver 5 through the liquid separator 5, and the concentrated sludge after the liquid is filtered is solid matter through the sludge outlet 9 of the drum screen 3. It is discharged from the discharge chute 10.

  A cleaning water supply pipe 12 is disposed at a position above the outer periphery of the drum screen 3 along the longitudinal direction of the drum screen 3, and a plurality of cleaning water nozzles 13 are attached to the cleaning water supply pipe 12. The washing water supply pipe 12 is supplied with high-pressure water boosted by a booster pump 14, and this high-pressure water is ejected from the washing water nozzle 13 toward the drum screen 3, thereby backwashing the drum screen 3. Is called. Here, the cleaning water for cleaning the drum screen 3 is ejected from the cleaning water nozzle 13 at a constant water pressure.

  However, in this conventional apparatus, in order to perform the cleaning of the drum screen 3 with certainty, the operation is performed with a margin, so that the cleaning water pressure or the amount of the cleaning water becomes excessive, resulting in an increase in the return water and the water treatment. There is a problem that the load on the system becomes large. Further, since the washing water pressure becomes excessive, the motor output as the whole apparatus becomes excessive, which causes an increase in running cost.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a method for operating a rotary drum type sludge concentrating device capable of reducing the return water load and the motor output. .

In order to achieve the above object, the operation method of the rotary drum type sludge concentrator according to the first invention is
A rotating drum type sludge concentrating device operating method for concentrating sludge introduced from one end of the screen while rotating a cylindrical screen having a large number of drainage portions around a horizontal axis,
The water pressure of the washing water sprayed for washing the screen can be set to a low washing water pressure lower than the standard water pressure and a high washing water pressure higher than the standard water pressure. Is operated by jetting cleaning water at the low cleaning water pressure, and is operated by switching the water pressure of the cleaning water from a low cleaning water pressure to a high cleaning water pressure at regular intervals.

The operation method of the rotary drum type sludge concentrator according to the second invention is as follows:
A rotating drum type sludge concentrating device operating method for concentrating sludge introduced from one end of the screen while rotating a cylindrical screen having a large number of drainage portions around a horizontal axis,
The amount of cleaning water sprayed to clean the screen can be set to a small amount of cleaning water smaller than the standard amount of water and a large amount of cleaning water larger than the standard amount of water. The operation is performed by injecting the cleaning water with the small amount of cleaning water and switching the amount of cleaning water from a small amount of cleaning water to a large amount of cleaning water at regular intervals.

  According to each of the above-mentioned inventions, since it is normally operated with a low washing water pressure or a small washing water amount, the motor output or return water load of the apparatus can be reduced, and the greenhouse gas emissions accompanying the reduction of the motor output Can be reduced. In addition, clogging can be eliminated more reliably by screen cleaning with a high cleaning water pressure or a large amount of cleaning water carried out at regular intervals, the concentration of concentrated sludge can be increased, and long-term stability of the equipment can be achieved. It becomes possible to drive.

  Next, specific embodiments of the operation method of the rotating drum type sludge concentrating device according to the present invention will be described with reference to the drawings.

  FIG. 1 is a front view of a rotary drum type sludge concentrating device according to an embodiment of the present invention.

  The rotating drum type sludge concentrating device (sludge concentrating device) 1 of the present embodiment is basically not different from that described as the conventional device. Therefore, the description of the parts common to the conventional apparatus will be omitted, and only the points peculiar to the present embodiment will be described below.

  In the sludge concentrating device 1 of the present embodiment, when the drum screen 3 is back-washed with high-pressure water ejected from the washing water nozzle 13, the washing water pressure of the booster pump 14 connected to the washing water supply pipe 12 is controlled. A controller 15 (such as a control device combining an electric valve and a manual valve) is provided. Under the control of the controller 15, the washing water pressure is normally set to a low washing water pressure (eg, 0.20 MPa or more) lower than the standard water pressure (eg, 0.40 MPa), and is set at regular intervals (eg, once within 3 hours). ) Only for a predetermined time (for example, 3 minutes or more), the operation is performed by increasing the cleaning water pressure higher than the standard water pressure (for example, 0.50 MPa or more). By combining the low washing water pressure and the high washing water pressure in this way, the amount of washing water can be reduced as a whole, and the load on the water treatment system of the entire plant can be reduced. In addition, since the washing water pressure is set to be low at normal times, the electric motor output of the washing water pump (boost pump 14) can also be reduced. In addition, by temporarily setting the cleaning water pressure to a high cleaning water pressure, it is possible to more reliably remove clogging of the drum screen 3 and contribute to stable operation over a long period of time.

  In the present embodiment, the operation is described with the washing water pressure being switched between the low washing water pressure and the high washing water pressure. However, the embodiment is configured such that the washing water amount is switched to the small washing water amount and the multiple washing water amount instead of the washing water pressure. Is possible. It is also possible to control the cleaning water pressure and the cleaning water amount in combination. As for the amount of washing water, it is preferable that the amount of washing water is 1.6 times or more with respect to the amount of washing water in order to prevent a reduction in concentration performance.

  In the present embodiment, a drum screen using a metal wedge wire has been described, but it goes without saying that the present invention can also be applied to other drum screens such as punching metal.

The front view of the rotating drum type sludge concentration apparatus which concerns on one Embodiment of this invention.

Explanation of symbols

1 Rotating drum type sludge concentrator 3 Drum screen (cylindrical screen)
5 Separation liquid receiver 6 Separator liquid discharge pipe 7 Sludge inlet 8 Sludge inlet pipe 9 Sludge outlet 10 Solid discharge chute 11 Sludge transport guide member 12 Washing water supply pipe 13 Washing water nozzle 14 Booster pump 15 Controller

Claims (2)

A rotating drum type sludge concentrating device operating method for concentrating sludge introduced from one end of the screen while rotating a cylindrical screen having a large number of drainage portions around a horizontal axis,
The water pressure of the washing water sprayed for washing the screen can be set to a low washing water pressure lower than the standard water pressure and a high washing water pressure higher than the standard water pressure. Is operated by jetting wash water at the low wash water pressure, and is operated by switching the wash water pressure from low wash water pressure to high wash water pressure at regular intervals. Method. A rotating drum type sludge concentrating device operating method for concentrating sludge introduced from one end of the screen while rotating a cylindrical screen having a large number of drainage portions around a horizontal axis,
The amount of cleaning water sprayed to clean the screen can be set to a small amount of cleaning water smaller than the standard amount of water and a large amount of cleaning water larger than the standard amount of water. The operation of the rotary drum type sludge concentrator is characterized in that it is operated by injecting the cleaning water with the small amount of cleaning water and switching the amount of cleaning water from a small amount of cleaning water to a large amount of cleaning water at regular intervals. Method.

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