JP4785454B2 - Method and apparatus for adjusting sludge solids supply in sludge dewatering machine - Google Patents

Description

  The present invention relates to a method and apparatus for adjusting the amount of sludge solids supplied in a sludge dewatering machine.

  As a means for adjusting the moisture content of the sludge, for example, as shown in FIGS. 1 and 2 of JP-A-2002-361299, the solid content concentration of the raw sludge is measured by a sludge concentration sensor provided in the mixing tank. The supply amount of the flocculant solution so that the ratio of the solid content of the sludge solid content and the solid content of the flocculant solution is determined with respect to the raw material sludge supplied within a predetermined time with reference to the measured solid content concentration, and When the operation time of the chemical liquid pump for the flocculant solution that supplies the flocculant solution is calculated, and when the flocculant solution is supplied to the raw material sludge and mixed and dehydrated based on the operation time, A predetermined amount of raw material sludge is supplied by the detection of the attached first liquid level sensor and measured with the sludge concentration sensor while stirring for a predetermined time so that the sludge concentration becomes uniform. When the supply amount of the flocculant solution is calculated based on the above settings and supplied to the mixing tank, and the mixed sludge mixed and stirred for a predetermined time with the predetermined amount of raw material sludge that has already been supplied can be supplied to the dehydrator The mixed sludge is supplied to the dehydrator and dehydration is started, and the liquid level of the mixed sludge stored in the mixing tank drops as the dehydration process proceeds, and is eventually attached to the mixing tank. When it is confirmed by the detection of the second liquid level sensor that the mixed sludge has disappeared, the process from the supply of the mixed sludge to the disappearance of the dewatering process is considered as one batch process, and the predetermined target sludge is determined. A method and apparatus for adjusting the moisture content of sludge, in which the batch treatment is repeated until the treatment amount is reached, is performed (see Patent Document 1).

JP 2002-361299 A (page 3-4, FIG. 1-2)

  However, in the batch processing method in which the dehydrator of Patent Document 1 is operated intermittently, it is necessary to spend a lot of time for the dewatering of sludge or use a large capacity dehydrator with a large dewatering capacity. In paragraph 0008 of Document 1, the sludge to be dewatered is treated as "... feeding raw material sludge 1a made of various sludges generated from an external sewage treatment plant or agricultural settlement wastewater treatment facility into the mixing tank 2". It is described that it is a method and apparatus, and sludge concentration sensors are classified into ultrasonic type, near-infrared light type, microwave type, etc. when classified according to the measurement principle. Since the measurement accuracy varies depending on the difference in water content, color, and sludge shape, etc., it is a principle to use a sludge concentration sensor that is originally adapted to the properties of the sludge. Therefore, even if the above various sludge concentration sensors are used, in order to automatically determine which sludge concentration sensor is actually a true value, a huge amount of data processing is required and the apparatus itself is complicated. Therefore, the manufacturing cost increases. Also, when trying to cope with one type of sludge concentration sensor, always monitor the change in the properties of the sludge to be dehydrated, and frequently carry out the troublesome manual correction by trial and error based on the properties over the years. Therefore, there is a drawback that the original performance of the dehydrator cannot be exhibited unless much labor and maintenance costs are applied.

  Further, in any of the sludge concentration sensors, since the concentration sensor is set and adjusted to a concentration range in which the concentration sensor is used, the error of the detected value increases as the concentration sensor deviates from the concentration range. In the case of the target, the sludge concentration fluctuates over a wide range every time the sludge flows in. Therefore, in order to detect a wide range of concentrations accurately, for example, a plurality of sludge concentration sensors with different detection ranges can be used. When switching to a sludge concentration sensor with an appropriate detection range or using one sludge concentration sensor, the detection range must be frequently changed and adjusted. Together, it makes it more complex and difficult to put into practical use.

  Therefore, in the method of the present invention, in order to continuously perform the sludge dewatering process, the sludge is transferred from the sludge storage tank containing the sludge to be dehydrated by the sludge transfer pump and temporarily stored in the sludge relay tank. The concentration of the sludge that has been made uniform by the sludge agitation pump in the sludge relay tank is measured by the concentration sensor, and the measured value is sent to the control unit of the control panel to be recognized as the concentration value for control. The amount of sludge supplied to the coagulation mixing tank is measured with a flow meter and the measured value is sent to the control unit of the control panel for recognition. The control sludge solids supply amount per hour calculated based on the control concentration value and the supply amount recognized in the control unit of the control panel is input in advance as a setting value of the calculation unit, and the control concentration From the value The frequency of the sludge supply amount and processing amount obtained by the calculation unit is output to the inverter that controls the rotation speed of the sludge supply pump and sludge dewatering machine, and the sludge supply pump and sludge dewatering machine are output based on the frequency. By controlling the rotation speed, the sludge solids supply amount per hour is supplied to the sludge dewatering machine via the coagulation mixing tank so that the amount of sludge solids supplied is constant as specified. The signal measured by the water level sensor attached to the control unit is sent to the calculation unit, and the control concentration value recognized by the calculation unit is corrected based on the detection signal. Based on the corrected control concentration value The main feature is that the sludge supply pump and the sludge dehydrator are operated and controlled so that the amount of sludge solids supplied to the dewatering capacity of the sludge dehydrator is automatically and optimally adjusted.

  Further, in the apparatus of the present invention, the above method is used to store a sludge storage tank containing sludge to be dewatered, a sludge relay tank for temporarily storing sludge supplied to the sludge dewatering machine, and a sludge in the sludge storage tank. A sludge transfer pump for transferring the sludge into the sludge relay tank, a drain pipe for draining the leaked sludge accumulated at the bottom of the sludge dehydrator into the sludge relay tank, and a drain for opening and closing the drain pipe A valve, a sludge agitation pump for making the sludge concentration in the sludge relay tank uniform, a concentration sensor for measuring the concentration of the sludge homogenized in the sludge relay tank, and agglomeration and mixing described later from within the sludge relay tank Accommodates sludge supply pump for supplying sludge to the tank, a flow meter for measuring the amount of sludge supplied by the sludge supply pump, and sludge supplied from the sludge relay tank to the sludge dehydrator Polymer flocculant A coagulation mixing tank for mixing, a polymer coagulant injection pump for injecting the polymer coagulant into the coagulation mixing tank, and a stirrer for mixing and stirring the polymer coagulant with sludge in the coagulation mixing tank And a control panel having a calculation unit for calculating the amount of sludge solids supplied to the sludge dehydrator based on the measured value by the concentration sensor and the flow meter, and a water level sensor for detecting the liquid level fluctuation in the tank The main feature is that an inverter for controlling the number of revolutions of the sludge supply pump and sludge dehydrator is provided in response to the output signal from the arithmetic unit.

  According to the present invention, even when various types of sludge having different properties are to be dewatered and continuously subjected to sludge dewatering treatment, it is possible to use a single type of sludge concentration sensor and a wide range without using various sludge concentration sensors. The measurement value measured by the sludge concentration sensor is appropriately corrected as needed for sludge concentration fluctuations, so that the dewatering capacity of the sludge dewatering machine is automatically adjusted even for sudden wide-range concentration fluctuations due to inflow sludge concentration. The amount of sludge solids that is optimally adjusted and automatically supplied from the coagulation mixing tank is automatically adjusted optimally, so that the device can be installed without increasing the size of the device itself and without requiring complicated control. There is an advantage in that the original performance of the sludge dewatering machine can be sufficiently exhibited without increasing the manufacturing cost because it is not complicated.

  The sludge is transferred from the sludge storage tank containing the sludge to be dewatered by the sludge transfer pump, temporarily stored in the sludge relay tank, and the concentration of sludge homogenized by the sludge agitation pump in the sludge relay tank is set. The measured value is measured by the concentration sensor, and the measured value is sent to the control unit of the control panel to be recognized as the control concentration value.The amount of sludge supplied from the sludge relay tank to the coagulation mixing tank by the sludge supply pump is measured with a flow meter. The measured value is sent to the control unit of the control panel and recognized, and the polymer flocculant is injected into the coagulation mixing tank and mixed with the sludge by the stirrer. Sludge solids supply amount per hour calculated based on the concentration value and supply amount is input in advance as a set value of the calculation unit, and the sludge supply amount and processing obtained by the calculation unit by back-calculating from the above control concentration value Dirty quantity frequency Output to the inverter that controls the rotation speed of the supply pump and sludge dewatering machine, and control the rotation speed of the sludge supply pump and sludge dewatering machine based on the frequency, so that the amount of sludge solids supply per hour is constant as specified. The sludge dehydrator is supplied via a coagulation mixing tank so that the fluctuation of the liquid level in the coagulation mixing tank supplying the sludge is sent to the arithmetic unit by the signal measured by the water level sensor attached to the tank. The amount of sludge solids supplied to the dewatering capacity of the sludge dehydrator is corrected based on the control concentration value recognized by the arithmetic unit based on the signal, and based on the corrected control concentration value The sludge supply pump and sludge dehydrator are operated and controlled so as to be automatically adjusted optimally.

  FIG. 1 is a block diagram showing the configuration of the apparatus of the present invention, wherein 1 is a sludge dewatering machine for separating sludge into filtrate and dewatered cake, 2 is a sludge storage tank containing sludge to be dewatered, 3 A sludge relay tank for temporarily storing sludge supplied to the sludge dewatering machine 1, 4 is a sludge transfer pump for transferring sludge in the sludge storage tank 2 into the sludge relay tank 3, and 5 is a screen for removing contaminants. , 6 is an inorganic flocculant injection pump, which is used when the inorganic flocculant is injected into the sludge relay tank 3 in advance to make the sludge colloidal. 18P is a drain pipe for draining the leaked sludge accumulated at the bottom of the sludge dehydrator into the sludge relay tank 3, 18V is a drain valve for opening and closing the drain pipe 18P, and 7 is in the sludge relay tank 3. The sludge agitation pump for equalizing the sludge concentration in the sludge, 8 is a concentration sensor for measuring the concentration of the sludge homogenized in the sludge relay tank 3, and 20a measures the liquid level fluctuation in the sludge relay tank 3. A water level sensor 9 for supplying the sludge from the sludge relay tank 3 to the agglomeration mixing tank 10 described later, and 11 a flow meter for measuring the amount of sludge supplied by the sludge supply pump 9. And provided in the discharge pipe of the sludge supply pump 9. 10 is a coagulation mixing tank for containing the sludge supplied from the sludge relay tank 3 to the sludge dewatering machine 1 and mixing the polymer coagulant, and 12 is for injecting the polymer coagulant into the coagulation mixing tank 10. A polymer flocculant injection pump, 13 is a dissolution unit panel, and 14 is a stirrer for mixing and stirring the polymer flocculant into sludge in the flocculent mixing tank 10, and measures the liquid level fluctuation in the flocculent mixing tank 10. A water level sensor 20b is provided. Reference numeral 15 denotes a control panel having an arithmetic unit 16 for calculating the amount of sludge solids supplied per hour to the sludge dehydrator 1 based on the measured values by the concentration sensor 8, the flow meter 11 and the water level sensor 20b. Yes. 17a is an inverter that receives the output signal from the calculation unit 16 and controls the rotation speed of the sludge supply pump 9, and 17b is an inverter that receives the output signal from the calculation unit 16 and controls the rotation speed of the sludge dehydrator 1.

  The sludge is transferred from the sludge storage tank 2 containing the sludge to be dehydrated by the sludge transfer pump 4 and temporarily stored in the small sludge relay tank 3 (if necessary, an inorganic flocculant is injected in advance to colloid In the sludge relay tank 3, the concentration of sludge homogenized by the sludge agitation pump 7 is measured by the concentration sensor 8, and the measured value is sent to the calculation unit 16 of the control panel 15 for control concentration. The amount of sludge supplied to the coagulation mixing tank 10 from the sludge relay tank 3 by the sludge supply pump 9 is measured by the flow meter 11 and the measured value is sent to the calculation unit 16 of the control panel 15. The polymer coagulant is injected into the coagulation / mixing tank 10 by the polymer coagulant injection pump 12 and mixed with the sludge by the stirrer 14, and the control concentration value and supply amount are calculated in the calculation unit 16 of the control panel 15. Based on While entering the calculated sludge solids supply amount per time in advance as a set value of the arithmetic unit 16, the sludge solids supply amount is calculated by Equation 1 below.

  Then, the frequency of the sludge supply amount obtained by calculating backward from the control concentration value is output to the inverter 17a that controls the rotation speed of the sludge supply pump 9 and the inverter 17b that controls the rotation speed of the sludge dehydrator 1. The sludge supply pump 9 and the sludge dehydrator 1 are controlled based on the frequency to supply the sludge solids supply amount to the sludge dewaterer 1 via the coagulation / mixing tank 10 so that the amount of sludge solids per hour is constant as predetermined. The signal measured by the water level sensor 20b attached in the agglomeration and mixing tank 10 for supplying the sludge is sent to the arithmetic unit, and is recognized by the arithmetic unit based on the detection signal. The control sludge dewatering capacity of the sludge dewatering machine 1 is automatically and optimally adjusted based on the corrected control concentration value. Like Operation control of the sludge supply pump 9 and the sludge dehydrator 1 is performed. In other words, when the recognized control concentration value is low, the sludge supply amount increases and the dewatering capacity corresponding to the sludge supply amount is adjusted. Conversely, when the control concentration value is high, the sludge supply amount decreases and corresponds to the sludge supply amount. In order to adjust the dewatering capacity, the sludge supply amount and the processing amount are made variable in response to the recognized variation in the control concentration value so as to keep the sludge solid matter supply amount to the sludge dewatering machine 1 constant. Therefore, there is no problem as in the case where the rotational speed of the sludge dehydrator is not controlled as in the conventional case described later.

  In the conventional sludge dewatering machine, the screw rotation speed shown in FIGS. 2 and 3 of the present invention is not variably controlled. Therefore, sludge with extremely low concentration below the detection range of the concentration detection sensor 8 used is a sludge relay tank. 3, a low-concentration detection signal with low detection accuracy is sent to the calculation unit 16 of the control panel 15 by the concentration sensor 8, and the sludge supply amount calculated by the above-described equation 1 is stored in advance. A speed increase command of the corresponding rotation speed is sent from the calculation unit 16 to the inverter 17a that controls the rotation speed of the sludge supply pump 9, whereby a large amount of sludge is rapidly supplied from the sludge supply pump 9 to the coagulation mixing tank 10. On the other hand, the amount of the polymer flocculant injected from the polymer flocculant injection pump 12 is not increased, but remains at the set value at the time of the sludge solids supply amount per hour, so that the increased supply To sludge Since the amount of flocculant added is insufficient, the sludge is agglomerated in a poorly coagulated state, and a large amount of poorly coagulated sludge far exceeding the filtration capacity of the sludge dehydrator 1 is rapidly supplied from the agglomeration mixing tank 10 and filtered. The supply line from the flocculation / mixing tank 10 to the sludge dehydrator 1 becomes completely dry due to sludge that cannot be removed, and the water level sensor 20b in the flocculation / mixing tank 10 frequently sends an upper limit full-water detection signal to the arithmetic unit 16, so that the detection Based on the signal, the computing unit 16 performs correction processing for the recognized control concentration value and simultaneously issues a stop command to the sludge supply pump 9, so that the sludge supply pump 9 frequently starts and stops. While the calculation unit 16 repeats the process of adding and correcting the concentration value for control, the sludge supply amount from the sludge supply pump 9 is gradually reduced based on the above-described equation 1 and eventually the sludge within the determination time. The number of start / stop times of the feed pump 9 becomes equal to the predetermined number of start / stop times, and the amount of sludge supplied from the sludge supply pump 9 is stabilized, but the control concentration value recognized at that time is the sludge relay tank 3 In this case, in contrast to the above, the amount of sludge supplied to the flocculation mixing tank 10 is small, whereas the amount is fed from the polymer flocculant injection pump 12. Since the amount of the polymer flocculant is not reduced and remains at the initial setting value of the sludge solids supply amount per hour, the amount of flocculant added becomes excessive with respect to the reduced amount of supplied sludge. Is supplied from the flocculation mixing tank 10 to the sludge dehydrator 1 in a state of poor flocculation. In any case where the addition amount of the flocculant is insufficient or excessive, the sludge discharged from the sludge dehydrator 1 by supplying sludge in a poorly coagulated state becomes a dehydrated cake containing a large amount of water and having a low dewatering efficiency. Thus, there arises a problem that it is not possible to obtain the sludge solids supply amount which is the initial target in the above formula 1.

  In contrast to the above, when sludge having an extremely high concentration exceeding the detection range of the concentration detection sensor 8 is supplied into the sludge relay tank 3 without performing variable control of the screw rotation speed shown in FIGS. The concentration sensor 8 sends a high-concentration detection signal with poor detection accuracy to the calculation unit 16 of the control panel 15, and a rotation speed reduction command corresponding to the sludge supply amount calculated by the equation 1 stored in advance. Is sent from the calculation unit 16 to the inverter 17a that controls the rotation speed of the sludge supply pump 9, so that the amount of sludge supplied from the sludge supply pump 9 to the agglomeration mixing tank 10 is reduced to a polymer agglomeration. The amount of the polymer flocculant injected from the agent injection pump 12 remains the set value at the time of the initial amount of sludge solids supplied per hour without being reduced. The amount of addition becomes excessive The sludge is supplied with a small amount of coagulation sludge that is far below the filtration capacity of the sludge dehydrator 1 from the coagulation / mixing tank 10 in the state of poor coagulation and immediately filtered, so the liquid level in the coagulation / mixing tank 10 is rapidly increased. Since the water level sensor 20b frequently sends a lower limit detection signal to the calculation unit 16, the calculation unit 16 corrects the control concentration value already recognized based on the detection signal, and at the same time, the sludge supply pump 9 Therefore, since the sludge supply pump 9 repeats speed increase frequently, the calculation unit 16 performs the subtraction correction processing of the control concentration value, so that the sludge supply pump 9 The amount of sludge supplied from the sludge supply pump 9 is increased while the sludge supply amount is gradually increased based on the above formula 1 and the number of times of start / stop of the sludge supply pump 9 within the determination time becomes equal to the predetermined number of start / stop times. Although stabilized, the control concentration value recognized at that time is recognized to be lower than the actual sludge concentration value in the sludge relay tank 3, and in this case, contrary to the above, supply to the coagulation mixing tank 10 The amount of the polymer flocculant injected from the polymer flocculant injection pump 12 is not increased, but the set value at the time of the initial amount of sludge solids supplied per hour is maintained without being increased. Therefore, since the amount of the flocculant added becomes insufficient with respect to the increased supply sludge, the sludge is supplied from the agglomeration mixing tank 10 to the sludge dehydrator 1 in a state of poor aggregation. In both cases where the addition amount of the flocculant is excessive or insufficient, the sludge discharged from the sludge dehydrator 1 by supplying sludge in a poorly aggregated state becomes a dehydrated cake containing a large amount of water and having a low dewatering efficiency. Thus, there arises a problem that it is not possible to obtain the sludge solids supply amount which is the initial target in the above formula 1.

  FIG. 2 is a flowchart showing the control of the inventive method according to another embodiment based on the adjustment method of the sludge solids supply amount in the sludge dewatering machine according to the first embodiment. The judgment time and the judgment start / stop count of the sludge supply pump at the judgment time are input as a set value, and the sludge according to the liquid level fluctuation measured by the water level sensor 20b provided in the coagulation mixing tank 10 based on the set value. The supply pump is controlled to start and stop, and the control concentration value recognized by the calculation unit is corrected according to the number of times the sludge supply pump is determined to start and stop at the determination time. Based on the corrected control concentration value By controlling the rotation speeds of the sludge supply pump 9 and the sludge dewatering machine 1, the amount of sludge solids supplied to the dewatering capacity of the sludge dewatering machine 1 is automatically and optimally adjusted.

  That is, the sludge solids supply amount actually contained in the sewage differs from the sludge solids supply amount with respect to the control concentration value measured and recognized by the sludge concentration sensor 8 due to the difference in sludge properties. When the amount of sludge solids contained is large, the sludge dewatering machine 1 having a quantitative property corresponding to the rotational speed used in the present invention has an excess supply exceeding a predetermined dewatering function. The untreated excess supply sludge overflowing from the machine 1 frequently causes the liquid level in the flocculation mixing tank 10 to reach the upper limit abnormal liquid level, so that the sludge is supplied by the measurement signal of the water level sensor 20b provided in the flocculation mixing tank 10. Since the pump 9 is repeatedly started and stopped, and the control concentration value of the current recognition is recognized to be lower than the actual sludge concentration by exceeding the number of times of determination start and stop of the sludge supply pump 9 in the determination time set above, Therefore, the value set as the added correction concentration value is added and corrected to the control concentration value recognized in the current state, and the sludge supply amount after correction from the equation 1 based on the newly recognized control concentration value after correction. And the frequency of the sludge supply amount obtained by the calculation unit 16 is output to the inverter 17a that controls the rotation speed of the sludge supply pump 9, and the rotation speed is lowered. At the same time, the sludge dewatering machine 1 is processed. It is determined whether or not the amount is appropriate, and when it is determined that the proper processing amount is appropriate, the sludge dewatering machine 1 maintains the current rotation speed, and when it is determined that the appropriate processing amount is small (decrease), the sludge dewatering device The speed increase command is output to the inverter 17b that controls the rotation speed of 1 to increase the rotation speed. Conversely, when it is determined that the appropriate processing amount is large (increase), the deceleration command is output to reduce the rotation speed. In any of the above determinations, the sludge dewatering machine 1 Feed rate is reduced, the determination of the determination start-stop times of the sludge supply pump in the determined time to correct the control concentration values are appropriately recognized repeated.

  Conversely, when the amount of sludge solids actually contained in the sewage is small, the sludge supplied to the sludge dehydrator 1 is immediately dehydrated and discharged because of an excessive supply below the dewatering function of the sludge dewaterer 1. Therefore, since the liquid level in the flocculation mixing tank 10 does not reach the upper limit full water abnormal liquid level, the sludge supply pump 9 is continuously operated without being started and stopped. Since the control concentration value for the current state recognition is recognized to be higher than the actual sludge concentration by falling below the determination start / stop count, the value set as the addition correction concentration value in advance is subtracted and corrected to the control concentration value for the current state recognition. Then, the corrected sludge supply amount is calculated from Equation 1 based on the newly recognized control concentration value after correction, and the frequency of the sludge supply amount obtained by the calculation unit 16 is calculated by the sludge supply pump 9. Inverter 17 for controlling the rotation speed At the same time as the rotation speed is increased, it is determined whether or not the amount of treatment of the sludge dewatering machine 1 at that time is appropriate. Is maintained, and when it is determined that the appropriate processing amount is small (decreased), a speed increase command is output to the inverter 17b that controls the rotation speed of the sludge dewatering machine 1, and the rotation speed is increased. When it is determined that there is a lot (increased), a deceleration command is output and the rotational speed is decelerated. In any of the above determinations, the sludge supply amount to the sludge dehydrator 1 is increased, and the sludge at the determination time is increased. The determination of the supply pump determination start / stop count is repeated, and the control concentration value recognized as appropriate is corrected.

  In addition, when the sludge solids supply amount with respect to the control concentration value recognized as the sludge solids supply amount actually contained in the sewage is equivalent, the determination start / stop count of the sludge supply pump 9 in the determination time of the above setting is Therefore, the sludge supply pump 9 and the sludge dewatering machine 1 are operated at the current rotation speed without correcting the control concentration value that is currently recognized. Accordingly, the sludge supply amount and the processing amount are automatically and optimally adjusted in response to the recognized variation in the control concentration value so as to keep the sludge solid matter supply amount to the sludge dewatering machine 1 constant. is there.

  FIG. 3 is a flowchart showing the control of the inventive method according to another embodiment on the premise of the method for adjusting the sludge solids supply amount in the sludge dewatering machine of Embodiment 1, and the allowable liquid level range for determination in the coagulation mixing tank 10 And the signal measured by the water level sensor 20b provided in the tank 10 is sent to the calculation unit, and the calculation unit determines that the liquid level in the flocculation mixing tank 10 is within the allowable liquid level range based on the detection signal. The control concentration value recognized by the calculation unit 16 is corrected according to the determination result, and the sludge is based on the corrected control concentration value. By controlling the rotation speeds of the supply pump 9 and the sludge dewatering machine 1, the amount of sludge solids supplied to the dewatering capacity of the sludge dewatering machine 1 is automatically and optimally adjusted.

  That is, the sludge solids supply amount actually contained in the sewage differs from the sludge solids supply amount with respect to the control concentration value measured and recognized by the sludge concentration sensor 8 due to the difference in sludge properties. When the amount of sludge solids contained is large, the sludge dewatering machine 1 having a quantitative property corresponding to the rotational speed used in the present invention has an excess supply exceeding a predetermined dewatering function. The untreated excess supply sludge overflowing from the machine 1 causes the liquid level in the flocculation / mixing tank 10 to reach the upper limit abnormal liquid level, and therefore the recognition of the current state is controlled by the measurement signal of the water level sensor 20b provided in the flocculation / mixing tank 10. Since the concentration value for use is recognized to be lower than the actual sludge concentration, the value set in advance as the added correction concentration value is added and corrected to the control concentration value for current recognition. Concentration value Then, the corrected sludge supply amount is calculated from the above equation 1, and the frequency of the sludge supply amount obtained by the calculation unit 16 is output to the inverter 17a that controls the rotation speed of the sludge supply pump 9, thereby reducing the rotation speed. At the same time, it is determined whether or not the processing amount of the sludge dewatering machine 1 at that time is appropriate, and if it is determined that the appropriate processing amount is appropriate, the mud dewatering machine 1 maintains the current rotational speed and the appropriate processing amount is small ( (Decrease), if it is judged that the speed increase command is output to the inverter 17b that controls the rotation speed of the sludge dewatering machine 1 and the rotation speed is increased. Outputs a deceleration command and decelerates the rotational speed, so that the sludge supply amount to the sludge dewatering machine 1 is reduced in any of the above determinations, and the allowable liquid level range for determination is set in the coagulation mixing tank 10. Correct the density value for control that is repeatedly recognized and recognized as appropriate.

  Conversely, when the amount of sludge solids actually contained in the sewage is small, the sludge supplied to the sludge dehydrator 1 is immediately dehydrated and discharged due to an excessive supply below the dewatering function of the sludge dewaterer 1. Therefore, the liquid level in the flocculation / mixing tank 10 reaches the lower limit abnormal liquid level, and therefore the control concentration value for the current recognition is recognized to be higher than the actual sludge concentration by the measurement signal of the water level sensor 20b attached in the flocculation / mixing tank 10. Therefore, the value set in advance as the subtraction correction density value is subtracted and corrected to the current density control density value, and after the correction based on the newly recognized control density value after correction, the above-mentioned formula 1 Sludge supply amount is calculated, the frequency of the sludge supply amount obtained by the calculation unit 16 is output to the inverter 17a that controls the rotation speed of the sludge supply pump 9, and the rotation speed is increased. The processing amount of machine 1 is It is determined whether or not it is correct, and when it is determined that the proper processing amount is appropriate, the mud dewatering machine 1 maintains the current rotation speed, and when it is determined that the appropriate processing amount is small (decrease), the sludge dewatering machine 1 A speed increase command is output to the inverter 17b that controls the rotation speed to increase the rotation speed. Conversely, when it is determined that the appropriate processing amount is large (increase), a deceleration command is output to reduce the rotation speed, In any of the above determinations, the amount of sludge supplied to the sludge dehydrator 1 is increased, and the determination of the allowable liquid level range for determination is repeated in the agglomeration mixing tank 10, and the control concentration value is recognized as appropriate. To correct.

  In addition, when the sludge solid supply amount with respect to the control concentration value recognized as the sludge solid supply amount actually contained in the sewage is equivalent, the liquid level in the coagulation mixing tank 10 is within the allowable liquid level range, The sludge supply pump 9 and the sludge dewatering machine 1 are operated at the current rotation speed without correcting the control-concentration value that is currently recognized. Therefore, the sludge supply amount and the processing amount are automatically variably adjusted in response to the recognized fluctuation of the control concentration sludge concentration, and the sludge solid matter supply amount to the sludge dehydrator 1 is kept constant. To do.

It is a block diagram of this invention apparatus. It is a flowchart of the control by one Example of this invention method. It is a flowchart of control by another Example of this invention method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sludge dewatering machine 2 Sludge storage tank 3 Sludge relay tank 4 Sludge transfer pump 6 Inorganic flocculant injection pump 7 Sludge agitation pump 8 Concentration sensor 9 Sludge supply pump 10 Agglomeration mixing tank 11 Flowmeter 12 Polymer flocculant injection pump 14 Stirrer 15 Control panel 16 Arithmetic unit 17a Inverter 17b that controls the rotation speed of sludge supply pump Inverter 17b that controls the rotation speed of sludge dehydrator 18P Drain pipe 18V Drain valve 20b Water level sensor

Claims (4)

  The sludge is transferred from the sludge storage tank containing the sludge to be dewatered by the sludge transfer pump, temporarily stored in the sludge relay tank, and the concentration of sludge homogenized by the sludge agitation pump in the sludge relay tank is set. The measured value is measured by the concentration sensor, and the measured value is sent to the control unit of the control panel to be recognized as the control concentration value.The amount of sludge supplied from the sludge relay tank to the coagulation mixing tank by the sludge supply pump is measured with a flow meter. Measure and send the measured value to the control unit of the control panel, inject the polymer flocculant into the coagulation mixing tank, and mix and agitate with sludge using a stirrer. Sludge solids supply amount per hour calculated based on the concentration value and supply amount is input in advance as a set value of the calculation unit, and the sludge supply amount and processing obtained by the calculation unit by back-calculating from the above control concentration value The amount of frequency Output to the inverter that controls the rotation speed of the mud supply pump and sludge dewatering machine, and control the rotation speed of the sludge supply pump and sludge dewatering machine based on the frequency to keep the sludge solids supply amount per hour constant The sludge dehydrator is supplied via a coagulation and mixing tank so that the liquid level fluctuation in the coagulation and mixing tank supplying the sludge is sent to the arithmetic unit by a signal measured by a water level sensor attached to the tank, Supply sludge solids supplied to the dewatering capacity of the sludge dehydrator based on the corrected control density value based on the corrected control density value based on the detection signal. A method for adjusting a sludge solids supply amount in a sludge dewatering machine, wherein the sludge feed pump and the sludge dewatering machine are operated and controlled so that the amount is automatically and optimally adjusted.   The judgment time for judgment of the calculation part and the number of times of judgment start / stop of the sludge supply pump at the judgment time are inputted as a set value in the control panel in advance, and measured by a water level sensor provided in the coagulation mixing tank based on the set value The sludge supply pump is controlled to start and stop according to the liquid level fluctuation signal, and the control concentration value recognized by the calculation unit is corrected according to the number of times the sludge supply pump is determined and stopped at the determination time. By automatically controlling the rotation speed of the sludge supply pump and sludge dehydrator based on the corrected control concentration value, the amount of sludge solids supplied automatically is optimized for the dewatering capacity of the sludge dewaterer. The method for adjusting a sludge solids supply amount in a sludge dewatering machine according to claim 1, wherein adjustment is performed.   An allowable liquid level range for determination is set in the coagulation mixing tank, and a signal measured by a water level sensor attached in the tank is sent to the calculation unit. The liquid level is determined to be within the allowable liquid level range, above the upper limit, or below the lower limit, and the control concentration value recognized by the calculation unit is corrected according to the determination result, By controlling the rotation speed of the sludge supply pump and sludge dewatering machine based on the control concentration value, the amount of sludge solids supplied to the dewatering capacity of the sludge dewatering machine can be adjusted automatically and optimally. The method for adjusting the amount of sludge solids supplied in the sludge dewatering machine according to claim 1, wherein   In a sludge dewatering machine for separating sludge into filtered water and dewatered cake, a sludge storage tank containing sludge to be dewatered, a sludge relay tank for temporarily storing sludge supplied to the sludge dewatering machine, and sludge Sludge transfer pump for transferring sludge from the storage tank into the sludge relay tank, drain pipe for draining the sludge accumulated at the bottom of the sludge dewatering machine into the sludge relay tank, and opening and closing the drain pipe A drain valve, a sludge agitation pump for homogenizing the sludge concentration in the sludge relay tank, a concentration sensor for measuring the concentration of the sludge homogenized in the sludge relay tank, and the sludge relay tank To the sludge supply pump for supplying sludge to the coagulation mixing tank, a flow meter for measuring the amount of sludge supplied by the sludge supply pump, and a sludge relay tank for supply to the sludge dehydrator Sludge A coagulation / mixing tank for mixing the polymer coagulant, a polymer coagulant injection pump for injecting the polymer coagulant into the coagulation / mixing tank, and a polymer coagulant in the coagulation / mixing tank. Calculate the amount of sludge solids supplied per hour to the sludge dehydrator based on the agitator for mixing and stirring the sludge, the water level sensor for detecting fluctuations in the liquid level in the coagulation mixing tank, and the concentration sensor and flow meter. Sludge solids supply in a sludge dewatering machine, comprising a control panel having a computing unit for performing the operation and an inverter that controls the rotation speed of the sludge supply pump and sludge dewatering machine in response to an output signal from the computing part Quantity adjustment device.

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