JP2006122875A - Solubilization treatment apparatus of sludge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize both of prevention of a stack of a contaminant in the vicinity of an ultrasonic generator and highly efficient sludge decomposition. <P>SOLUTION: A solubilization treatment apparatus of sludge 11 includes a solubilization treatment tank 25 having the ultrasonic generator 39, a circulation pipe 42 connected to the inflow 26 side of the solubilization treatment tank 25 by branching from an outflow pipe 20B connecting the outflow port 27 of the solubilization treatment tank 25 with the downstream side, and a circulation pump 40 for delivering a part of the sewage flowing from the outflow port 27 to the outflow pipe through the circulation pipe 42 to the inflow 26 side. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sludge solubilization apparatus that decomposes and solubilizes activated sludge generated in a wastewater treatment facility.

  In a wastewater treatment facility equipped with a biological treatment tank that purifies sewage with activated sludge, a large amount of excess sludge is generated. Therefore, the sludge taken out from the biological treatment tank is decomposed and solubilized by a sludge solubilization apparatus, and then re-introduced into the biological treatment tank to reduce the amount of sludge.

  For example, there is known a sludge solubilization processing device that generates cavitation with ultrasonic waves generated by an ultrasonic oscillator, thereby decomposing and solubilizing sludge (Patent Documents 1 and 2 and the present application). (See Japanese Patent Application No. 2004-96).

  This type of sludge solubilization apparatus will be described with reference to FIG. An ultrasonic generator 2 is disposed in the solubilization treatment tank 1. An inflow pipe 3 from an upstream side such as a sedimentation tank (not shown) is connected to the inlet 1a of the solubilization tank 1. A mud supply pump 4 is disposed in the inflow pipe 3. On the other hand, an outflow pipe 5 to the downstream side of a biological tank (not shown) is connected to the outlet 1b of the solubilization tank 1. Sewage containing sludge supplied from the inlet 1 a by the mud feed pump 4 is discharged from the outlet 1 b through the flow path 1 c in the solubilization treatment tank 1. Cavitation is generated by the ultrasonic waves generated by the ultrasonic generator 2, and the sludge is decomposed and solubilized by the energy generated from the generation to the disappearance of the cavitation.

  However, foreign substances contained in the sewage in the solubilization treatment tank 1 may accumulate in the vicinity of the ultrasonic generator 2. If this foreign matter is accumulated, the ultrasonic generation efficiency of the ultrasonic generator 2 is reduced, and the sludge decomposition efficiency is reduced. In particular, when the flow rate of sewage containing sludge supplied from the upstream side (mud supply flow rate) is small, the flow rate of sewage in the solubilization treatment tank 1 becomes slow, so that foreign matter is deposited near the ultrasonic generator. Cheap.

  FIG. 8 shows an improved sludge solubilization apparatus for reducing or preventing foreign matter accumulation near the ultrasonic transmitter. A similar configuration is disclosed in FIG. In FIG. 8, the same elements as those in FIG. 7 are denoted by the same reference numerals.

  The sludge solubilization treatment apparatus of FIG. 8 is characterized in that a circulation pipe 6 and a sewage tank 7 are provided in order to circulate sludge in the solubilization treatment tank 1. One end of the circulation pipe 6 is connected to the outlet 1b of the solubilization treatment tank 1, and the other end is opened to a space in the waste water tank 7 above the surface of the waste water. A circulation pump 8 that is a submersible pump is disposed in the sewage tank 7. The other end of the discharge pipe 9 is connected to the discharge port of the circulation pump 8, and the other end of the discharge pipe 9 is connected to the inlet 1 a of the solubilization treatment tank 1. The inflow pipe 3 is connected to the sewage tank 7. An outflow pipe 5 is connected to the sewage tank 7.

  The sewage containing the sludge from the upstream side flows into the sewage tank 7 by the mud pump 4, and then flows into the solubilization tank 1 from the inlet 1 a through the discharge pipe 9 by the circulation pump 8. Sewage discharged from the outlet 1 b of the solubilization treatment tank 1 is discharged to the sewage tank 7 through the circulation pipe 6. The sewage returned to the sewage tank 7 is supplied again to the solubilization tank 1 by the circulation pump 8. Further, the sewage in the sewage tank 7 flows downstream through the outflow pipe 5. Since the sewage is circulated in the solubilization tank 1 by the circulation pipe 6 and the sewage tank 7, the flow rate in the solubilization tank 1 is maintained at a high speed even when the flow rate of the mud supply is small, thereby the ultrasonic generator. Foreign matter accumulation in the vicinity of 1 can be prevented.

  However, the sludge solubilization apparatus of FIG. 8 has the following problems.

  First, since the amount of sewage containing sludge existing in the circulation pipe 6 and the sewage tank 7 (circulation sewage amount) is large, solubilization treatment cannot be performed efficiently.

  Secondly, since the sewage is discharged from the circulation pipe 6 to the sewage tank 7 as described above, bubbles are easily generated in the sewage tank 7. When the bubbles are mixed into the sewage supplied into the solubilization tank 1, the ultrasonic generation efficiency of the ultrasonic generator 2 is lowered.

  Thirdly, the sewage tank 7 cannot have a sealed structure. Therefore, bubbles of sewage (scum) overflow from the sewage tank 7 due to the generation of the bubbles.

  4thly, if the sewage tank 7 is provided, an apparatus will enlarge. Moreover, since the sludge density | concentration becomes non-uniform | heterogenous by sludge sedimentation etc. in the sewage tank 7, the stirring apparatus 10 is required. In these respects, the sludge solubilization apparatus of FIG. 8 is large and expensive.

Japanese Patent Laid-Open No. 11-128975 JP 2002-200209 A

  An object of the present invention is to provide a small and low-cost sludge solubilization apparatus capable of decomposing sludge with high efficiency while preventing or suppressing the accumulation of foreign matters in the vicinity of an ultrasonic transmitter. .

  The present invention relates to a sludge solubilization treatment apparatus that decomposes and solubilizes sludge generated by biological treatment of sewage, solubilization treatment in which sewage containing the sludge is supplied from an inlet and discharged from an outlet. A tank, an ultrasonic generator for generating ultrasonic waves in the solubilization tank, an outlet pipe connecting the outlet and the downstream side of the solubilization tank, and an inlet of the solubilization tank A circulation pipe that is connected to the side of the solubilization tank and a part of the sewage flowing into the outflow pipe from the outlet of the solubilization tank to the inlet side of the solubilization tank via the circulation pipe A sludge solubilization processing apparatus is provided, comprising a pump.

  Cavitation occurs in the sewage in the solubilization tank due to the ultrasonic waves generated by the ultrasonic generator. Sludge is decomposed by the energy generated from the occurrence of cavitation to the disappearance. A part of the sewage including sludge flowing into the outflow pipe from the outlet of the solubilization tank is returned to the inlet of the solubilization tank through the circulation pipe by the circulation pump. Therefore, even when the flow rate of sewage containing sludge supplied from the upstream side to the inlet of the solubilization tank (mud supply flow rate) is small, the flow rate of sewage in the solubilization tank is maintained at a high speed, thereby Accumulation of foreign substances contained in the sewage near the sound wave generator can be prevented.

  In addition, since the outlet of the solubilization tank and the inlet are connected by a circulation pipe without providing a sewage tank for circulation, it is provided for circulation existing at the outlet and the inlet of the solubilization tank. The amount of sewage containing sludge (circulated sewage amount) is relatively small. Therefore, the time (processing time interval) required for all the sewage of the circulating sewage to pass through the solubilization treatment tank can be shortened, and the efficiency of the sludge solubilization treatment can be increased.

  Furthermore, since the circulation sewage tank is not provided and the circulation pipe can be a sealed structure, the overflow of sewage bubbles is eliminated, and the mixing of bubbles into the sewage can be greatly reduced. The smaller the amount of bubbles present in the solubilization tank, the higher the energy of cavitation generated by the ultrasonic waves generated by the ultrasonic generator, and the higher the efficiency of sludge decomposition in the solubilization tank.

  Furthermore, since no sewage tank for circulation is provided, the apparatus can be reduced in size and cost.

  The circulation pipe may further include a gas-liquid separation tank (separator) disposed at a portion branched from the outflow pipe, and the circulation pump may be a submersible pump disposed in the gas-liquid separation tank. .

  By providing the gas-liquid separation tank, bubbles can be separated from the sewage containing sludge that is returned to the inflow port of the solubilization tank through the circulation pipe. Therefore, even when the amount of bubbles generated in the solubilization tank is large, the amount of bubbles in the solubilization tank can be suppressed. The smaller the amount of bubbles present in the solubilization tank, the higher the energy of cavitation generated by the ultrasonic waves transmitted from the ultrasonic generator, and the higher the efficiency of sludge decomposition in the solubilization tank. Therefore, by providing the gas-liquid separation tank, sludge can be decomposed with high efficiency even when the amount of bubbles generated in the solubilization tank is large.

  The sludge solubilization treatment apparatus of the present invention includes a circulation pipe branched from the outflow pipe and connected to the inflow side of the solubilization treatment tank, and a part of the sewage water through the circulation pipe. A circulation pump that circulates to the side, so that the flow rate of sewage in the solubilization tank is maintained at a high speed even when the flow rate of the mud is small, thereby accumulating foreign matter contained in the sewage near the ultrasonic generator. Can be prevented. Moreover, the efficiency of the sludge solubilization process can be improved by shortening the processing time interval. Further, there is no problem such as mixing of bubbles into sewage. Furthermore, it is possible to reduce the size and cost of the apparatus.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
FIG. 1 shows a sewage treatment facility 12 including the sludge solubilization treatment apparatus 11 according to the first embodiment of the present invention shown in FIG. The sewage treatment facility 12 includes a flow rate adjustment tank 13, a biological treatment tank 14, an aeration device 15, a precipitation tank 16, a concentration tank 17, and a storage tank 18.

  The organic wastewater to be treated is supplied to the biological treatment tank 14 via the flow rate adjustment tank 13. By aeration with the air supplied from the aeration device 15, the aerobic biological treatment is performed on the sewage supplied to the biological treatment tank 14. Sewage containing sludge produced by biological treatment is introduced into the sedimentation tank 16 and separated into treated supernatant water and sedimented sludge. The supernatant water is discharged from the pipe 19 to the outside of the facility. On the other hand, a part of the settled sludge is returned to the biological treatment tank 14, and the remainder is concentrated in the concentration tank 17 and then stored in the storage tank 18. A part of the sludge in the storage tank 18 is withdrawn from the storage tank 18 and subjected to processing such as incineration. In the present embodiment, a pipe returning from the storage tank 18 to the flow rate adjustment tank 13 is provided, and the sludge solubilization processing apparatus 11 is provided in this pipe. Specifically, an inflow pipe 20 </ b> A that is a pipe connecting the storage tank 18 and the sludge solubilization treatment apparatus 11 and an outflow pipe 20 </ b> B that is a pipe connecting the sludge solubilization treatment apparatus 11 and the flow rate adjustment tank 13 are provided. It has been. A part of the sludge in the storage tank 18 is supplied to the sludge solubilization treatment device 11 through the inflow pipe 20A, decomposed and solubilized by the sludge solubilization treatment device 11, and then the outflow pipe 20B and the flow rate adjustment tank 13. Is returned to the biological treatment tank 14.

  Referring to FIG. 2, the sludge solubilization treatment apparatus 11 includes a reactor or a solubilization treatment tank 25 to which sludge containing sludge is supplied from a storage tank 18 (upstream side). The solubilization tank 25 has an inlet 26 near the lower end and an outlet 27 near the upper end. The inflow port 26 is connected to the storage tank 18 (upstream side) through the inflow pipe 20A. The outflow port 27 is connected to the flow rate adjusting tank 13 (downstream side) through the outflow pipe 20B. The bottom wall of the solubilization tank 25 is provided with a discharge port 28 for discharging internal sewage, and a discharge valve 29 that is normally closed is provided at the discharge port 28.

  Inside the solubilization treatment tank 25, a flow path that meanders from the inlet 26 to the outlet 27 is formed by a plurality of parallel partition walls 31. Specifically, in the figure of the solubilization tank 15, partition walls 31 alternately extend from the left and right side walls 32, 33, between the bottom wall 34 and the partition wall 31, between the top wall 35 and the partition wall 31, and A plurality of flow paths 37 extending in the horizontal direction are formed between two adjacent partition walls 31. Moreover, the two flow paths 37 adjacent to each other in the vertical direction communicate with each other by a communication portion 38 provided at either one of the left and right ends thereof. In this embodiment, five channels 37 extending in the horizontal direction are formed in the solubilization tank 25. Each channel 37 is provided with an oscillator 39 as an ultrasonic generator. The oscillator 39 has a well-known structure. When a series of pulse voltages are applied from the high frequency power supply 45, an ultrasonic wave having a frequency corresponding to a time interval between pulse waveforms is continuously generated. The frequency of the ultrasonic wave generated by the oscillator 39 is set in the range of about 20 kHz to about 1 MHz, for example.

  A mud supply pump 40 is provided in the inflow pipe 20A. The sludge containing the sludge from the storage tank 18 is pumped to the inlet 26 of the solubilization treatment tank 25 by the mud supply pump 40. In order to prevent the backflow from the solubilization tank 25 to the inflow pipe 20 </ b> A, it is preferable to use a positive displacement pump such as a screw pump or a rotary pump as the mud supply pump 40.

  The outflow pipe 20B is provided with an outflow valve 41 that is normally open.

  A circulation pipe 42 is branched from a position P1 between the outlet 27 of the outlet pipe 20B and the outlet valve 41. The circulation pipe 42 joins the inflow pipe 20 </ b> A at a position P <b> 2 between the mud supply pump 40 and the inlet 26. A circulation pump 43 is provided in the circulation pipe 42. The circulation pump 43 has a suction port 43a connected to the outflow pipe 20B side and a discharge port 43b connected to the inflow pipe 20A side. Therefore, a part of the sewage containing the sludge flowing into the outflow pipe 20B from the outlet 27 of the solubilization tank 25 is sent to the inlet 26 of the solubilization tank 25 via the circulation pipe 42 by the circulation pump 43.

  The control panel 46 controls the operations of the high frequency power supply 45, the mud supply pump 40, the circulation pump 43, and the discharge valve 29 according to the input operation command.

  Next, operation | movement of the sludge solubilization processing apparatus 11 of this embodiment is demonstrated. At the time of sludge solubilization treatment or operation, the mud supply pump 40 is driven, and each oscillator 39 oscillates ultrasonic waves by application of a pulse voltage. The sludge containing sludge is sent from the inlet 16 into the solubilization tank 25 by the mud feed pump 40, and flows through the flow path 37 toward the outlet 27 as shown by the arrow A in the figure. The sewage flowing out from the outlet 27 flows to the flow rate adjustment tank 13 through the outlet pipe 20B.

  Cavitation is continuously generated in the sewage containing the sludge in the solubilization treatment tank 25 by the ultrasonic waves generated by the oscillator 39, and the sludge is decomposed by the energy generated from the generation to the disappearance of the cavitation, solubilizing. Is done. The solubilized sludge is sent to the biological treatment tank 14 for reduction.

  Along with the mud supply pump 40, the circulation pump 43 is also driven. Part of the sewage discharged from the inlet 27 of the solubilization tank 25 to the outflow pipe 20B flows into the circulation pipe 42 from the position P1, and flows into the inflow pipe 20A from the position P2 through the circulation pump 43 (arrow B). reference). In other words, from the outlet 27 of the solubilization tank 25 to the inlet 26 of the solubilization tank 25 through the outflow pipe 20B, the position P1, the circulation pipe 42, the circulation pump 43, the position P2, and the inflow pipe 20A. A circulation flow path is formed. Accordingly, even when the flow rate of the sewage containing sludge supplied to the inlet 26 of the solubilization treatment tank 25 by the mud supply pump 40 (mud supply flow rate) is small, the flow rate of the sewage in the solubilization treatment tank 25 is maintained at a high speed. Accordingly, it is possible to prevent the accumulation of foreign matters contained in the sewage near the transmitter 39.

  The mud supply flow rate of the sludge solubilization processing apparatus of the present embodiment is set in a range of, for example, 2 L / min to 40 L / min according to the scale of the processing facility. Moreover, when the mud supply flow rate is within this range, the flow rate (circulation flow rate) of sewage returned from the outlet 27 of the solubilization tank 25 to the inlet 26 by the circulation pump 43 ranges from 6 L / min to 120 L / min. Set to

  In the sludge solubilization apparatus of this embodiment, the outlet 27 and the inlet 26 of the solubilization tank 25 are connected by the circulation pipe 42. In other words, the sewage tank 7 is not provided for the circulation of sewage provided in the sludge solubilization treatment apparatus shown in FIG. Therefore, in the sludge solubilization treatment apparatus of this embodiment, the amount of sewage (circulation sewage amount) including sludge provided for circulation existing in the outlet 26 and the inlet 27 of the solubilization tank 25 is shown in FIG. Significantly less than the sludge solubilization treatment device shown. Therefore, the time (processing time interval) required for all the sewage of the circulating sewage to pass through the solubilization treatment tank can be shortened, and the efficiency of the sludge solubilization treatment can be increased.

  In the sludge solubilization processing apparatus 11 of this embodiment, the feed flow rate is 2 L / min, the circulation flow rate is 80 L / min, the capacity of the solubilization tank 25 (reactor capacity) is 30 L, and the outlet 27 of the solubilization tank 25 If the capacity (circulation pipe capacity) of the pipe (circulation pipe 42) from the inlet to the inlet 26 is 1.5L, the amount of circulating sewage is 1.5L (circulation pipe capacity). Further, the processing time interval is obtained by dividing the sum (31.5 L) of the reactor capacity (30 L) and the circulating sewage amount (1.5 L) by the circulating flow rate (80 L / min), and is about 0.4 minutes. .

  On the other hand, if the sludge solubilization treatment apparatus in FIG. 8 has the same mud supply flow rate, circulation flow rate, reactor capacity, and circulation pipe capacity as in the above example, and the capacity of the sewage tank 7 is 200 L, the circulating sewage amount is 201.5 L ( The sum of the capacity of the circulation pipe and the capacity of the sewage tank). The processing time interval is obtained by dividing the sum (231.5L) of the reactor capacity (30L) and the amount of circulating sewage (201.5L) by the circulating flow rate (80L / min), and is about 2.8 minutes. .

  Comparing both, if the mud supply flow rate and the circulation flow rate are the same, using the sludge solubilization treatment device of this embodiment, compared with the sludge solubilization treatment device comprising the sewage tank 7 shown in FIG. The processing time interval is reduced by about 1/7.

  As described above, the sludge solubilization apparatus according to the present embodiment does not include the circulation sewage tank 7 and the circulation pipe 42 can have a sealed structure, so that overflow (overflow) of bubbles (scum) of sewage is caused. Elimination of bubbles in sewage can be greatly reduced. The smaller the amount of bubbles present in the solubilization treatment tank 25, the higher the energy of cavitation generated by the ultrasonic waves generated by the oscillator 39. Therefore, the decomposition efficiency of the sludge in the solubilization processing tank 25 can be improved by reducing the mixing of bubbles into the sewage.

  Moreover, since the sludge solubilization processing apparatus of this embodiment is not equipped with the sewage tank 7 and the stirring apparatus 10 (all refer FIG. 8), it is small and low-cost.

(Second Embodiment)

  FIG. 3 shows the sludge solubilization processing apparatus 11 of the second embodiment of the present invention. A gas-liquid separation tank or separator 60 is provided at a position P1 where the circulation pipe 42 branches from the outflow pipe 20B. A relatively inexpensive and small vortex submersible pump 70 is disposed in the separator 60 as a circulation pump. Specifically, the outlet 27 of the solubilization tank 25 and the separator 60 are connected by a part of the outflow pipe 20B, and the separator 60 and the flow rate adjustment tank 12 are connected by the remaining part of the outflow pipe 20B. Further, one end of the circulation pipe 42 is connected to the discharge port of the submersible pump 70, and the other end of the circulation pipe 42 is connected to the inflow pipe 20A at the position P2 as in the first embodiment. A space is left above the surface of the sewage in the separator 60, and air bubbles contained in the sewage that has flowed into the space are separated into gas and liquid.

  The sewage flowing out from the outlet 27 of the solubilization tank 25 is returned to the inlet 26 of the solubilization tank 25 through the circulation pipe 42 after the bubbles are separated by the separator 60. Therefore, even when the amount of bubbles generated in the solubilization tank 25 is large, the amount of bubbles in the solubilization tank 25 can be suppressed and sludge can be decomposed with high efficiency.

  Since other configurations and operations of the second embodiment are the same as those of the first embodiment, the same elements are denoted by the same reference numerals and description thereof is omitted.

  4-5 shows the alternative of the arrangement | positioning location in the sewage treatment facility 12 of the sludge solubilization processing apparatus 11 of this invention. As shown in FIG. 4, a conduit 50 for circulating the sewage in the biological treatment tank 14 may be provided, and the sludge solubilization treatment apparatus 11 of the first or second embodiment may be provided in the conduit 50. Further, as shown in FIG. 5, the pipes (inflow pipe 20 </ b> A, outflow pipe 20 </ b> B) returning from the storage tank 18 to the flow rate adjustment tank 13 and the pipe lines 50 for circulating the sewage in the biological treatment tank 14 are respectively first. Or you may provide the sludge solubilization processing apparatus 11 of 2nd Embodiment. Furthermore, as shown in FIG. 6, a pipe 51 that once branches from the pipe returning from the sedimentation tank 16 to the biological treatment tank 14 and joins again is provided, and the sludge solubilization treatment apparatus 11 is provided in this pipe 51. good.

It is a block diagram which shows a sewage treatment facility provided with the sludge solubilization processing apparatus which concerns on 1st Embodiment of this invention. It is a mimetic diagram showing the sludge solubilization processing device concerning a 1st embodiment of the present invention. It is a schematic diagram which shows the sludge solubilization processing apparatus which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the 1st alternative of a sewage treatment facility provided with the sludge solubilization processing apparatus of this invention. It is a block diagram which shows the 2nd alternative of a sewage treatment facility provided with the sludge solubilization processing apparatus of this invention. It is a block diagram which shows the 3rd alternative of a sewage treatment facility provided with the sludge solubilization processing apparatus of this invention. It is a schematic diagram which shows an example of the conventional sludge solubilization processing apparatus. It is a schematic diagram which shows the other example of the conventional sludge solubilization processing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Sludge solubilization processing apparatus 12 Sewage treatment equipment 13 Flow rate adjustment tank 14 Biological treatment tank 15 Aeration apparatus 16 Precipitation tank 17 Concentration tank 18 Reservoir 20A Inflow pipe 20B Outflow pipe 25 Solubilization processing tank 26 Inlet 27 Outlet 28 Outlet 29 Discharge valve 31 Partition wall 32, 33 Side wall 34 Bottom wall 35 Top wall 37 Flow path 38 Communication portion 39 Oscillator 40 Mud pump 41 Outflow valve 43 Circulation pump 45 High frequency power supply 46 Control panel 60 Separator 70 Circulation pump

Claims (2)

In the sludge solubilization equipment that decomposes and solubilizes sludge generated by biological treatment of sewage,
A solubilization treatment tank in which sewage containing the sludge is supplied from an inlet and discharged from an outlet;
An ultrasonic generator for generating ultrasonic waves in the solubilization bath;
A circulation pipe branched from the outflow pipe connecting the outlet and the downstream side of the solubilization tank, and connected to the inlet side of the solubilization tank;
A circulation pump for circulating a part of the sewage flowing into the outflow pipe from the outlet of the solubilization tank to the inlet side of the solubilization tank through the circulation pipe. , Sludge solubilization treatment equipment.   The sludge solubilization treatment apparatus according to claim 1, further comprising a gas-liquid separation tank disposed in a portion where the circulation pipe branches from the outflow pipe.

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