JP5230673B2 - Sludge concentration method and sludge concentration apparatus - Google Patents

Description

  The present invention relates to a sludge concentrating method and a sludge concentrating device for temporarily storing cleaning wastewater generated in a filtration facility and then concentrating the cleaning wastewater with an immersion membrane installed in a membrane immersion tank.

  Patent Documents 1 and 2 below describe a method of temporarily storing cleaning wastewater generated in a filtration facility in a cleaning drainage tank and filtering and concentrating the cleaning wastewater supplied therefrom.

  That is, in Patent Document 1 below, a turbidity measuring device for measuring the turbidity concentration of the cleaning wastewater flowing into the cleaning drainage tank is provided, and a raw water supply device for supplying raw water for turbidity adjustment to the cleaning drainage tank is provided, Based on the turbidity concentration by the turbidity measuring device, the raw water supply amount from the raw water supply device is controlled so that the turbidity concentration of the cleaning wastewater in the cleaning drainage tank becomes a predetermined value, and the cleaning wastewater is efficiently concentrated. It has been proposed.

  However, in patent document 1, since the turbidity measuring device and the raw water supply device for supplying the raw water to the washing drainage tank are provided, there is a problem that the equipment including the accompanying pipe becomes large and the manufacturing cost increases. In addition, although the concentration of the cleaning wastewater supplied from the cleaning drainage tank is kept constant, the raw water is supplied to the cleaning drainage tank to dilute the cleaning wastewater. Was lowering.

  Further, in Patent Document 2 below, at least a part of the concentrated sludge discharged by separating the supplied sludge from the sludge supply tank by the membrane separator is returned to the sludge supply tank, and the remainder is discharged out of the system. When the circulating operation is performed and the sludge concentration of the concentrated sludge rises to a predetermined value, it is switched to the discharge operation that discharges the entire amount of the concentrated sludge discharged from the membrane separation device outside the system, and the sludge concentration of the concentrated sludge decreases to the predetermined value. In this case, by switching to the above-mentioned circulation operation, the concentration of the membrane separation device can be stably maintained without complicated control even when the fluctuation of the sludge concentration of the raw sludge is large, and is finally discharged out of the system. It has been proposed to set the sludge concentration of sludge to a certain target value. Moreover, in order to manage with the sludge density | concentration of concentrated sludge, measuring with the sludge concentration meter arrange | positioned in the membrane separation tank is described in embodiment.

  However, in Patent Document 2, the sludge concentration in the membrane separation tank has temporal and spatial unevenness. For example, when the sludge on the membrane surface is peeled off by physical cleaning of the membrane, the sludge concentration before and after that is changed over time. In addition, the sludge concentration increases toward the bottom due to the sludge settling. Therefore, if there is no regulation for sludge concentration measurement conditions or discharge conditions when discharging, switch to a discharge operation that discharges the entire amount out of the system despite the need to further increase the sludge concentration of the concentrated sludge to be discharged. In some cases, the portion that needs to be further increased in the sludge concentration is discharged. Furthermore, in order to manage with the sludge concentration, there is a problem that a sludge concentration meter is required and the manufacturing cost increases.

JP 2001-310186 A JP 2003-320400 A

  The present invention has been made in order to solve the above-mentioned problems, and the object of the present invention is to manage the sludge concentration of cleaning wastewater discharged without using a sludge densitometer with high manufacturing cost. It is.

  In addition, wash effluent that has room to further increase the sludge concentration is prevented, and only wash effluent concentrated to the specified sludge concentration is efficiently discharged to reduce the amount of wash effluent discharged. It is.

In order to achieve the above object, the sludge concentration method according to claim 1 of the present invention introduces raw water into a filtration facility through an introduction pipe provided with a turbidimeter and a flow meter, and filters the turbidimeter and An introduction step in which an arithmetic unit calculates an integrated turbidity amount based on each measurement value of the flow meter, a storage step for temporarily storing in a washing drain a washing wastewater generated by filtering raw water in the introduction step, a filtration step of filtering by submerged membrane which is installed inside filled with been cleaned waste water stored in the cleaning sump with storing step to film dipping bath, the submerged membrane to the sludge the film immersion deposited in the filtration step a physical washing step of peeling during cleaning waste water of the bath, a sludge concentration method and a discharge step of the physical washing step with exfoliated sludge discharging a portion of the cleaning waste water turbid from the film dipping bath, The filtration step and the physical cleaning work A plurality of times, after the physical washing step of the integrated turbidity of raw water was calculated by the calculation device is performed first after a predetermined value that correlates with the sludge concentration in the wash effluent of the membrane immersion tank, The transfer time is secured and the discharge process is performed.

  The sludge concentration method according to claim 2 of the present invention is characterized in that, in the sludge concentration method according to claim 1, the transition time is 3 minutes or more.

Moreover, the sludge concentration apparatus which concerns on Claim 3 of this invention is the filtration equipment which filters the raw | natural water introduce | transduced from the inlet pipe which the turbidimeter and the flow meter are attached, and each of the said turbidimeter and the said flow meter An arithmetic device that calculates the integrated turbidity amount from the measured value, a cleaning drainage tank that temporarily stores the cleaning drainage generated by filtering with the filtration facility, and a dipping tank that contains the cleaning drainage from the cleaning drainage tank. A membrane dip tank for filtration by a membrane, a physical cleaning means for peeling sludge adhering to the dip film into the cleaning waste water of the membrane immersion tank, and the calculation correlated with the sludge concentration of the cleaning waste water in the membrane immersion tank. After the physical cleaning by the physical cleaning means first performed after the accumulated turbidity amount of the raw water calculated by the apparatus reaches a predetermined value, a part of the cleaning wastewater in which the sludge is turbid is secured by securing a transition time. Discharging means for discharging from the immersion tank; It is characterized in that it comprises.

  According to the present invention having the above-described configuration, the arithmetic unit calculates the integrated turbidity amount based on the measured values of the turbidity meter and the flow meter attached to the inflow pipe, and is discharged with the calculated integrated turbidity amount. Therefore, it is not necessary to measure the sludge concentration in the cleaning wastewater with a sludge densitometer. Accordingly, it is not necessary to install a sludge concentration meter, and it is possible to concentrate the sludge concentration in the washing wastewater with a manufacturing facility that keeps costs low.

  In addition, since the sludge concentration in the wash effluent can be managed by the accumulated turbidity, the wash effluent that has room to further increase the sludge concentration is discharged due to variations in the measurement method and measurement position using the sludge concentration meter. Can be prevented, and the amount of cleaning wastewater discharged can be reduced. Therefore, it is possible to reduce the labor and cost for treating the cleaning waste water.

  Furthermore, after the first physical cleaning performed after the accumulated turbidity amount calculated by the arithmetic unit reaches a predetermined value, the cleaning wastewater is discharged after securing the transition time. Only the washing drainage that has settled in the lower part and stayed in the lower part of the membrane immersion tank reaching a predetermined sludge concentration can be discharged from the drainage pipe installed in the lower part. Accordingly, it is possible to prevent the discharge of the cleaning wastewater in which the sludge has not yet settled and reach the predetermined sludge concentration, and the labor and cost for treating the cleaning wastewater can be reduced.

  If at least 3 minutes is secured as the transition time, only the cleaning waste water in the membrane immersion tank in which the sludge separated by physical cleaning settles and is concentrated to a predetermined sludge concentration can be efficiently discharged.

Schematic explanatory diagram of the sludge concentration apparatus according to the present invention Table for elapsed time and sludge concentration after physical cleaning Table for wastewater discharge and sludge concentration Graph of changes in accumulated turbidity

  With reference to drawings, the sludge concentration method and the sludge concentration apparatus which concern on embodiment of this invention are illustrated and demonstrated below.

  FIG. 1 is a schematic explanatory diagram of a sludge concentration apparatus 1 according to the present invention. The sludge concentrating device 1 includes a filtration facility 10, a computing device 20, a cleaning drainage tank 30, a membrane immersion tank 40, a physical cleaning means 50, and a discharge means 60.

  The filtration facility 10 has one end connected to an introduction pipe 11 connected at one end to a raw water tank (not shown) for introducing the raw water, and a later-described washing drain tank 30 to which cleaning wastewater generated by filtering the raw water is fed. The cleaning drain pipe 12 is connected to the water purification pipe 13 having one end connected to a water purification tank (not shown) through which purified water filtered from the raw water is fed. Further, the introduction pipe 11 is provided with a turbidimeter 16 for measuring the raw water turbidity of the raw water passing therethrough and a flow meter 17 for measuring the raw water flow rate. The filtration facility 10 is a facility for filtering raw water to obtain purified water, and corresponds to a filtration facility such as a membrane filtration facility or a sand filtration facility.

  The arithmetic unit 20 calculates the accumulated amount of turbidity of the raw water that has passed through the introduction pipe 11 based on the respective measured values measured by the turbidimeter 16 and the flow meter 17, and turbidity at predetermined time intervals. The product of the raw water turbidity measured by the meter 16 and the raw water flow measured by the flow meter 17 is calculated and integrated. The accumulator 20 performs control so that the integrated turbidity amount shifts to a discharge process after a physical cleaning process, which will be described later, first performed after the accumulated turbidity amount reaches a predetermined value. The calculation device 20 is connected to the turbidity meter 16 and the flow meter 17 by wire or wireless so that the measurement values of the turbidity meter 16 and the flow meter 17 can be received.

  The cleaning drain 30 is a water tank that receives and temporarily stores the cleaning drain from the filtration facility 10, and is connected to the cleaning water distribution pipe 12, and supplies the temporarily stored cleaning drain to the membrane immersion tank 40 described later. One end of the cleaning drainage supply pipe 31 is connected.

  The membrane immersion tank 40 is connected to the other end of the cleaning drainage supply pipe 31 so that the cleaning drainage from the cleaning drainage tank 30 flows in and is filled inside by the supply pump 32 attached to the cleaning drainage supply pipe 31. It has become. The immersion membrane 41 installed in the interior is immersed in washing waste water, and is formed by laminating a large number of elements each having a hollow fiber membrane stretched in a screen shape, and the upper end is fixed by a fixing plate 42. The fixed plate 42 is connected to the other end of a membrane filtration treated water pipe 46 which is attached with a membrane filtration pump 47 and one end of which is connected to the water purification tank described above. As the membrane filtration pump 47 attached to the membrane filtration water pipe 46 sucks, the washing wastewater in the membrane immersion tank 40 is filtered by the immersion membrane 41, and the filtered membrane filtration water is connected to the fixed plate 42. The sludge that has been sent to the water purification tank through the membrane filtration treatment water pipe 46 and has not been able to pass through the immersion membrane 41 adheres to the inner holes and the surface of the immersion membrane 41, whereby the washing waste water is filtered.

  The physical washing means 50 includes a backwash water tank 51 and a backwash pipe 52 having one end connected to the backwash water tank 51 and the other end connected between the membrane filtration pump 47 of the membrane filtration water pipe 46 and the fixed plate 42. The backwash pipe 52 is provided with a backwash pump 53. In the physical cleaning means 50 configured in this way, purified water is supplied from the backwash water tank 51 by the backwash pump 53, and the fixed plate is passed from the backwash pipe 52 through the membrane filtration water pipe 46 in the direction opposite to that during filtration. Since the water is fed from 42 to the submerged membrane 41, the sludge adhering to the inner hole and the surface of the submerged membrane 41 is separated into the cleaning wastewater in the membrane immersion tank 40, thereby concentrating the sludge concentration in the cleaning wastewater. The

  The discharge means 60 includes a drainage pipe 61 connected to the lower part of the membrane immersion tank 40, and is physically cleaned by the physical cleaning means that is first performed after the accumulated turbidity amount reaches a predetermined value under the control of the arithmetic unit. After that, the transition time is secured, and a part of the cleaning wastewater staying in the lower part in the membrane immersion tank 40 is discharged from the lower part by the drainage pipe 61 connected at the lower part. Yes.

  Next, a method for concentrating the sludge concentration of the cleaning wastewater generated by filtering raw water in the sludge concentrating device 1 having the above-described configuration will be described.

  The raw water flows through the introduction pipe 11 from the raw water tank by a water pump (not shown) attached to the introduction pipe 11 and is sent to the filtration facility 10. At this time, the turbidity meter 16 and the flow meter 17 attached to the introduction pipe 11 constantly measure the raw water turbidity and the raw water flow rate flowing through the introduction pipe 11, and the arithmetic unit 20 has a predetermined time. Then, the product of these measured values is calculated and integrated.

  The raw water flowing into the filtration facility 10 is filtered and separated into purified water and washing waste water, the purified water flows through the water purification pipe 13 and stored in the water purification tank, and the washing waste water flows through the washing drain pipe 12 and is washed into the washing drain. 30.

  The cleaning wastewater temporarily stored in the cleaning drainage tank 30 is sucked by the supply pump 32 attached to the cleaning drainage supply pipe 31, and is sent to the film immersion tank 40 and filled. The washing wastewater in the membrane immersion tank 40 is filtered by the immersion membrane 41 immersed in the washing wastewater by being sucked by the membrane filtration pump 47 connected to the fixed plate 42 and attached to the membrane filtration water pipe 46. The membrane filtration treated water that has passed through the immersion membrane 41 flows through the membrane filtration treated water pipe 46 via the fixed plate 42 and is sent to the water purification tank, and a sludge is attached to the immersion membrane 41. If this filtration step is continuously performed for a certain period of time, the filtration efficiency decreases due to the sludge adhering to the submerged membrane 41. Therefore, a predetermined condition such as a predetermined time or a stage when the filtration efficiency has decreased to a predetermined value is set, and the predetermined The filtration process stops when the set value of the condition is reached, and the process moves to the physical cleaning process.

  Next, in the physical cleaning process, the sludge adhering to the immersion film 41 is peeled into the cleaning waste water in the film immersion tank 40. That is, the backwash pump 53 attached to the backwash pipe 52 having one end connected to the backwash water tank 51 is operated, and the purified water from the backwash water tank 51 is supplied to the membrane filtration treatment water pipe 46 from the backwash pipe 52. It is made to distribute | circulate in the reverse direction to the time of a filtration process from the fixing plate 42 to the immersion film 41 via a part. Thereby, the sludge adhering to the inner hole and the surface of the immersion film 41 is peeled into the cleaning waste water filled in the film immersion tank 40. At this time, if the accumulated turbidity amount does not reach the predetermined value, even if the washing waste water is further filtered, the load on the immersion membrane 41 is small, so the process proceeds to the filtration process again, and then the physical washing process and Repeatedly. When the accumulated turbidity amount reaches a predetermined value, the process proceeds to a discharge process described below under the control of the arithmetic unit.

  In the discharge process, after the transition time after the physical cleaning process is secured, a part of the cleaning wastewater filled in the film immersion tank 40 is connected to the lower part of the film immersion tank 40 by a drainage pipe 61. It is discharged as if it is pulled out from below. That is, since the sludge adhering to the immersion film 41 is peeled off by physical cleaning and becomes turbid in the cleaning waste water of the film immersion tank 40, the sludge is discharged after a certain transition time until the sludge settles down. A part of the cleaning wastewater discharged is only the cleaning wastewater staying in the lower part of the membrane immersion tank 40 where the sludge has settled and the sludge concentration has reached a predetermined value.

  In FIG. 2, the state which the sludge density | concentration of the sludge suspended in the washing | cleaning waste_water | drain staying in the lower part of the film | membrane immersion tank 40 changes with the elapsed time after physical washing | cleaning is shown. From this result, the sludge concentration is concentrated to 1.7% after 3 minutes from the physical cleaning, and the sludge concentration is concentrated to 2.1% after 5 minutes. After that, the sludge concentration hardly changes. Therefore, after securing the transition time of 3 minutes after the physical cleaning, it is preferable to shift to the discharging process, and more preferably, the transition time of 5 minutes after the physical cleaning is secured.

  In FIG. 3, the transition time is secured after the first physical cleaning performed after the accumulated turbidity amount reaches a predetermined value, and a certain amount (in the example shown in the figure, controlled to discharge 10 L) of cleaning waste water is discharged. Shows the sludge concentration of the sludge contained therein. As can be seen from the example of FIG. 3, it can be understood that the sludge concentration changes at a constant value when a certain amount of washing wastewater is discharged.

  FIG. 4 shows the state of transition of the integrated turbidity amount over time. As shown in this figure, the time required for the accumulated turbidity amount to reach a predetermined value varies. That is, the amount or turbidity of raw water filtered by the filtration facility 10 varies. However, after the accumulated turbidity amount reaches a predetermined value (↓ portion shown in FIG. 4), when discharging is performed, the amount of sludge contained in the discharged cleaning wastewater is constant as shown in FIG. That is, there is a correlation between the accumulated turbidity amount of the raw water introduced into the filtration facility 10 and the sludge amount contained in the washing wastewater staying in the lower part of the membrane immersion tank 40. Therefore, it is possible to use the accumulated turbidity amount for the management of the sludge concentration of the cleaning wastewater in the membrane immersion tank 40. It is possible to manage the sludge concentration.

  As described above, the sludge concentration of the washing wastewater in the membrane immersion tank 40 is managed by the integrated turbidity amount calculated based on the measured values of the turbidimeter 16 and the flow meter 17 installed in the introduction pipe 11. Therefore, it is not necessary to install a sludge concentration meter in the membrane immersion tank 40, and it is possible to concentrate the sludge of the washing wastewater with a manufacturing facility that keeps costs low.

  In addition, since the sludge concentration of the cleaning wastewater at the time of discharge is determined by the integrated turbidity amount calculated by the arithmetic unit 20, the cleaning wastewater that has room to further increase the sludge concentration due to variations in the measurement of the sludge concentration meter is discharged. Can be prevented.

  Furthermore, after the physical cleaning performed first after the integrated turbidity amount calculated by the arithmetic unit 20 reaches a predetermined value, a part of the cleaning wastewater staying in the lower part of the membrane immersion tank 40 is secured after securing the transition time. Since it is discharged, the sludge separated by physical cleaning settles in the lower part of the cleaning wastewater, and only the cleaning wastewater staying in the lower part of the membrane immersion tank 40 reaching the predetermined sludge concentration is installed in the lower part. It can be discharged from the tube 61. Therefore, it becomes possible to discharge the cleaning waste water in which the sludge has not yet settled and has not reached the predetermined sludge concentration.

DESCRIPTION OF SYMBOLS 1 Sludge concentrator 10 Filtration equipment 11 Introducing pipe 12 Washing drain pipe 13 Purifying pipe 16 Turbidimeter 17 Flow meter 20 Arithmetic apparatus 30 Washing drain tank 31 Washing drain supply pipe 32 Supply pump 40 Membrane immersion tank 41 Submerged membrane 42 Fixed plate 46 Membrane filtration treated water pipe 47 Membrane filtration pump 50 Physical cleaning means 51 Backwash water tank 52 Backwash pipe 53 Backwash pump 60 Discharge means 61 Drainage pipe

Claims (3)

Introducing raw water into a filtration facility with a turbidimeter and a flow meter attached to the filtration facility and filtering, and an arithmetic unit calculates an integrated turbidity amount based on the measured values of the turbidimeter and the flow meter A step of temporarily storing the cleaning wastewater generated by filtering the raw water in the introduction step in the cleaning drainage tank, and filling the membrane immersion tank with the cleaning wastewater stored in the cleaning drainage tank in the storage step A filtration step of filtering with a submerged membrane installed inside, a physical cleaning step of stripping sludge adhering to the submerged membrane in the filtration step into the cleaning waste water of the membrane soaking tank, and a separation step in the physical cleaning step A sludge concentration method including a discharge step of discharging a part of the washing wastewater in which the sludge is turbid from the membrane immersion tank,
First , after the filtration step and the physical cleaning step are repeated a plurality of times , and the accumulated turbidity amount of the raw water calculated by the arithmetic unit correlating with the sludge concentration of the cleaning waste water in the membrane immersion tank reaches a predetermined value. A sludge concentration method characterized by securing a transition time after the physical cleaning step to be performed and shifting to the discharge step. In the sludge concentration method of Claim 1,
The sludge concentration method, wherein the transition time is 3 minutes or more. Filtration equipment for filtering raw water introduced from an introduction pipe provided with a turbidity meter and a flow meter, an arithmetic unit for calculating an integrated turbidity amount from each measured value of the turbidity meter and the flow meter, and the filtration A cleaning drainage tank that temporarily stores cleaning wastewater generated by filtration in equipment, a membrane immersion tank that filters cleaning wastewater from the cleaning drainage tank with an immersion film installed inside, and adheres to the immersion film The accumulated turbidity amount of the raw water calculated by the calculation device correlating with the physical cleaning means for peeling the sludge into the cleaning waste water of the membrane immersion tank and the sludge concentration of the cleaning waste water in the membrane immersion tank becomes a predetermined value. After the physical cleaning by the physical cleaning means performed first after reaching, it has a discharge means for securing a transition time and discharging a part of the cleaning waste water in which the sludge becomes turbid from the membrane immersion tank. Sludge concentrator.

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