JP6621659B2 - Sludge treatment method and sludge treatment apparatus in water treatment facility - Google Patents

Description

  The present invention relates to a method and apparatus for treating sludge in a water treatment facility such as sewage, and in particular, changes in the concentration and mixing ratio of the mixed sludge between the initial settling sludge and the excess concentrated sludge stored in the mixed sludge storage tank. It relates to the technology to suppress.

  In general, sewage introduced into a sewage treatment facility is first sedimented in a sedimentation basin, and then first sedimentation sludge (raw sludge) is settled and separated in the first sedimentation basin, and then organic matter is decomposed by microorganisms in the aeration tank. The activated sludge is settled and separated in the final sedimentation basin, and the supernatant is subjected to treatment such as disinfection and discharged. On the other hand, a part of the activated sludge is returned to the aeration tank and used for the decomposition of the organic matter, and the excess activated sludge (surplus sludge) is treated as follows along with the initial settling sludge.

  That is, the sewage treatment facility is provided with a water treatment facility for treating the initial sludge and surplus sludge, and after the initial sludge and surplus sludge are flowed into the mixed sludge storage tank of the water treatment facility and mixed. Then, it is concentrated and dewatered by a sludge dewatering machine and finally incinerated.

  For example, in Patent Document 1, a flocculant is added to the mixed sludge of primary settling sludge and excess sludge to perform primary flocculation treatment, and then the mixed sludge having finished the primary flocculation treatment has a sludge concentration of 6 to 6. A technique is disclosed in which a concentration treatment is performed to 8%, a coagulant is added to the mixed sludge after the concentration treatment, a secondary agglomeration treatment is performed, and a dewatering treatment is further performed on the mixed sludge subjected to the secondary agglomeration treatment. ing.

Japanese Patent No. 4129479

  By the way, the properties of primary sludge and surplus sludge are different, and the concentration of primary sludge tends to vary greatly depending on the environment such as rainfall and water quality, but the concentration of surplus sludge is hardly affected by the environment. Further, the amount of the flocculant injected into the dehydrator varies depending on the mixing condition of the sludge.

  Therefore, in order to make the amount of fuel and coagulant used economically when the mixed sludge mixed with primary sludge and excess sludge is concentrated and dehydrated and then burned, the concentration and mixing ratio of the mixed sludge (mixing ratio) Ratio) must be managed properly.

  Therefore, in patent document 1 mentioned above, the concentration process is performed so that it may become a predetermined sludge density | concentration after carrying out the primary coagulation process of the mixed sludge. However, the technique disclosed in Patent Document 1 requires a separate facility for performing a concentration process after the primary agglomeration process, which not only increases the cost of the equipment but also cannot be handled by existing equipment. is there.

  Furthermore, the technique disclosed in Patent Document 1 further requires a secondary agglomeration treatment in which a flocculant is added after the concentration treatment after the primary agglomeration treatment. There are also problems that are lacking.

  Therefore, the object of the present invention is to appropriately control the concentration and mixing ratio of the primary sludge and excess sludge flowing into the mixed sludge storage tank using existing equipment, and the amount of flocculant added during dehydration The present invention also provides a sludge treatment method and a sludge treatment apparatus in a water treatment facility excellent in economic efficiency by suppressing the amount of fuel used when combusting mixed sludge.

In order to achieve the above-mentioned object, the sludge treatment method in the water treatment facility of the present invention comprises the initial sedimentation sludge stored in the primary sedimentation sludge storage tank and the surplus concentration sludge stored in the surplus concentration sludge storage tank. In the sludge treatment method in a water treatment facility for drawing out and supplying the mixed sludge storage tank to the mixed sludge storage tank, and extracting and dewatering the mixed sludge of the primary sedimentation sludge stored in the mixed sludge storage tank and the excess concentrated sludge. The concentration of settled sludge and the supply flow rate to the mixed sludge storage tank , and the concentration of the excess concentrated sludge and the supply flow rate to the mixed sludge storage tank are measured over time and stored in the mixed sludge storage tank. Estimating the blending ratio of the primary sedimentation sludge and the excess concentrated sludge, obtaining the mixed sludge concentration that is the concentration of the mixed sludge drawn out from the mixed sludge storage tank, and determining the mixed sludge concentration and the blending ratio. Compared with the preset target mixed sludge concentration and target mixing ratio, the primary sedimentation sludge and the excess concentration are adjusted so that the mixed sludge concentration and the mixing ratio approach the target mixed sludge concentration and target mixing ratio. The supply flow rate to the mixed sludge storage tank with sludge is controlled.

In this case, the mixed sludge concentration is compared with the target mixed sludge concentration and the mixed sludge concentration is made closer to the target mixed sludge concentration to the mixed sludge storage tank of the primary sedimentation sludge and the excess concentrated sludge. The mixed sludge storage of the primary sedimentation sludge and the excess concentrated sludge for obtaining the concentration-based supply flow rate of each, comparing the blending ratio with the target blending ratio, and bringing the blending ratio close to the target blending ratio The mixing ratio main supply flow rate to the tank is respectively determined, and based on the concentration main supply flow rate and the mixing ratio main supply flow rate of the primary sediment concentration sludge, the supply flow rate of the primary sediment concentration sludge to the mixed sludge storage tank is determined. The mixed sludge is determined according to the priority of the mixed sludge concentration and the blending ratio, and the mixed sludge of the surplus concentrated sludge is determined based on the concentration main supply flow and the blend ratio main supply flow of the excess concentrated sludge The supply flow rate to the reservoir, it is preferably determined according to the priority of the mixed sludge concentration and the mixing ratio.

  Moreover, the sludge treatment apparatus in the water treatment facility of the present invention comprises an initial sediment concentration sludge storage tank for storing an initial sediment concentration sludge obtained by concentrating the initial sediment sludge, and an excess concentrated sludge obtained by concentrating the excess sludge discharged after the sludge treatment. The excess concentrated sludge storage tank to be stored, the mixed sludge storage tank for mixing and storing the primary sedimentation sludge and the excess concentrated sludge, the primary sedimentation sludge stored in the mixed sludge storage tank, and the surplus A sludge dewatering machine for dewatering the mixed sludge with the concentrated sludge, and a first sludge feeding means for extracting the first settling concentrated sludge stored in the first settling concentrated sludge storage tank and feeding it to the mixed sludge storage tank; A second sludge feeding means for extracting the surplus concentrated sludge stored in the surplus concentrated sludge storage tank and feeding it to the mixed sludge storage tank; and the mixed sludge stored in the mixed sludge storage tank. Pull out and send to the sludge dehydrator The first sludge feeding means, the first concentration detecting means for detecting the concentration of the initial sedimentation sludge, and the flow rate of feeding the primary sedimentation sludge by the first sludge feeding means to the mixed sludge storage tank. The first flow rate detecting means for detecting the excess sludge, the second concentration detecting means for detecting the concentration of the excess concentrated sludge, and the flow rate of the surplus concentrated sludge supplied by the second sludge feeding means to the mixed sludge storage tank A second flow rate detecting means for detecting; a third concentration detecting means for detecting the mixed sludge concentration; and a third flow rate for detecting a flow rate of the mixed sludge supplied to the sludge dehydrator by the third sludge feed means. Detection means, and control means for controlling the flow rates of the first sludge feed means and the second sludge feed means supplied to the mixed sludge storage tank, wherein the control means is configured to detect the third concentration. While obtaining the mixed sludge concentration by means, Based on the history of the concentration and flow rate detected by the first concentration detection means, the first flow rate detection means, the second concentration detection means, and the second flow rate detection means, Mixed sludge property calculating means for estimating the mixing ratio of primary sedimentation sludge and excess concentrated sludge, the mixed sludge concentration detected by the third concentration detecting means and the mixing ratio estimated by the mixed sludge property calculating means, The first sludge feeding means for comparing the set target mixed sludge concentration and the target blending ratio, and bringing the mixed sludge concentration and the blending ratio close to the target mixed sludge concentration and the target blending ratio, and the first 2 It is provided with the sludge supply amount calculating means which sets each flow volume with a sludge feeding means.

In this case, the sludge supply amount calculating means compares the mixed sludge concentration detected by the third concentration detecting means with the target mixed sludge concentration so that the mixed sludge concentration approaches the target mixed sludge concentration. Each of the primary sediment concentration sludge and the excess concentrated sludge is supplied to the mixed sludge storage tank, and the mixing ratio of the mixed sludge is compared with the target mixing ratio to determine the mixing ratio. In order to approach the mixing ratio, the primary concentration flow of the primary sedimentation sludge and the excessive concentration sludge to the mixed sludge storage tank are respectively determined as the primary mixing flow rate of the primary sedimentation concentration sludge, Based on the main supply flow rate, the supply flow rate to the mixed sludge storage tank of the initial settling sludge is determined according to the preset priority of the mixed sludge concentration and the mixing ratio, the excess sludge concentration Determining based on said density mainly supply flow rate and the mixing ratio main supply flow rate, the supply flow rate to the mixing sludge storage tank of the excess thickened sludge, depending on the preset priority of the mixed sludge concentration and the mixing ratio It is preferable to do.

According to the present invention, the mixing ratio between the initial sedimentation sludge stored in the mixed sludge storage tank and the excess concentrated sludge is estimated, and the concentration of the mixed sludge withdrawn from the mixed sludge storage tank is measured, and these are the target combinations. Ratio and the supply flow rate to the mixed sludge storage tank of the initial settling sludge and surplus concentrated sludge are controlled so as to approach the target mixed sludge concentration. It is possible to appropriately control the concentration and mixing ratio of the stored primary sludge and excess sludge. As a result, the amount of flocculant added during dehydration and the amount of fuel used when burning the mixed sludge are suppressed, and excellent economic efficiency can be obtained.

It is a schematic block diagram of a water treatment facility. It is a schematic block diagram of a mixed sludge control unit. It is a flowchart which shows a sludge process routine. (A) is a time chart which shows the control state of mixed sludge density | concentration, (b) is a time chart which shows the control state of the mixing ratio of mixed sludge, (c) is the relationship between the density | concentration and mixing ratio of mixed sludge which considered the weight. It is a chart which shows.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In a sewage treatment system, sewage discharged from a factory or household is first introduced into a sand settling basin to remove sand, and then first settling sludge (raw sludge) is settled and separated in the first settling pond. After that, the sewage is poured into the aeration tank, the microorganisms are decomposed, the activated sludge from the aeration tank is settled and separated in the final sedimentation tank, the supernatant is poured into the chlorine-mixing pond, disinfection, etc. Discharge. A part of the activated sludge settled in the final sedimentation basin is returned to the aeration tank and reused for reaction with organic matter.

  On the other hand, the first settling sludge that has been separated into the first settling basin and the surplus sludge that is the remaining activated sludge that has been settling into the final settling pond are sent to the water treatment facility 1 shown in FIG. . The water treatment facility 1 is provided with an initial sedimentation sludge storage tank 2 for storing initial sedimentation sludge and an excess sludge storage tank 3 for storing excess sludge.

  The primary sedimentation sludge storage tank 2 concentrates the infused primary sedimentation sludge by gravity, and is equipped with a sludge interface meter 2a for detecting the sludge interface and a sludge scraper (not shown), and operates the sludge scraper. This can increase the gravity concentration of the initial sludge. On the other hand, the excess sludge stored in the excess sludge storage tank 3 is concentrated by the centrifugal concentrator 4 and stored in the excess concentrated sludge storage tank 5. The centrifugal concentrator 4 has a variable rotational speed within the range of the motor capacity, so that the concentration of excess sludge can be set as appropriate.

  Furthermore, the primary sedimentation sludge stored in the primary sedimentation sludge storage tank 2 and concentrated by gravity, and the excessive concentrated sludge stored and concentrated in the superconcentration sludge storage tank 5 are introduced into the mixed sludge storage tank 6. Mixed. Reference numeral 6 a is a water level meter that detects the water level of the mixed sludge stored in the mixed sludge storage tank 6.

  Further, the mixed sludge generated by mixing the primary sedimentation sludge and the excess concentrated sludge stored in the mixed sludge storage tank 6 is drawn out by the mixed sludge supply pump 22 and dehydrated by the sludge dehydrator 7. As a result, a dehydrated cake is formed and sent to an incinerator (not shown).

  Further, an initial sedimentation sludge supply pump 11 as a first sludge feeding means from the upstream side to an initial sedimentation sludge line 8 for feeding the primary sedimentation sludge from the primary sedimentation sludge storage tank 2 to the mixed sludge storage tank 6. And a first flow meter 12 as a first flow rate detection means and a first concentration meter 13 as a first concentration detection means.

  Moreover, the surplus concentration sludge supply pump 16 as a 2nd sludge supply means and 2nd density | concentration are supplied to the surplus concentration sludge line 9 which supplies surplus concentration sludge from the surplus concentration sludge storage tank 5 to the mixed sludge storage tank 6 from the upstream side. A second densitometer 17 as detection means and a second flow meter 18 as second flow rate detection means are interposed. Further, a fourth concentration meter 30 as a fourth concentration detecting means is interposed in a centrifugal concentration sludge line 29 for supplying the centrifugal concentrated sludge from the upstream centrifugal concentrator 4 to the excess concentrated sludge storage tank 5.

  Further, a third concentration meter 21 serving as a third concentration detecting means and a mixed sludge serving as a third sludge feeding means from the upstream side to a mixed sludge line 10 for supplying the mixed sludge in the mixed sludge storage tank 6 to the sludge dewatering machine 7. A supply pump 22 and a third flow meter 23 as third flow rate detecting means are interposed. The surplus sludge stored in the surplus sludge storage tank 3 is fed to the centrifugal concentrator 4 by a surplus sludge supply pump 27 interposed in the surplus sludge line 26.

Each sludge supply pump 11, 16, 22 extracts sludge stored in each storage tank 2, 5, 6 and supplies it to the downstream side, and varies the sludge flow rate within the pump capacity range. Can do. The first to third flow meters 12, 18, and 23 detect the supply flow rates Q1 to Q3 [m ³ / h] of the sludge flowing through the sludge lines 8, 9, and 10, respectively. 4 concentration meter 13, 17, 21, 30 detects the density | concentration C1-C4 [%] of the sludge which distribute | circulates each sludge line 8-10,29. Reference numerals 28a and 28b are inlet valves provided downstream of the sludge lines 8 and 9, and each sludge supplied to the mixed sludge storage tank 6 by opening and closing the inlet valves 28a and 28b individually. The timing can be changed. The concentration of the concentrated sludge by the centrifugal concentrator 4 is variably controlled so as to become a preset target value based on the sludge concentration C4 detected by the fourth densitometer 30.

  As shown in FIG. 2, the driving of each of the sludge supply pumps 11, 16, and 22 is controlled by the sludge treatment control unit 31. The sludge treatment control unit 31 is composed of a microcomputer and its peripheral devices, and has a well-known CPU, ROM, RAM, nonvolatile memory, etc., and the CPU follows each control program stored in the ROM. The operation of the sludge supply pumps 11, 16, and 22 is controlled. In addition to the control program, the ROM stores fixed data such as various table data.

  The first to third flow meters 12, 18, 23 and the first to fourth densitometers 13, 17, 21, 30 are connected to the input side of the sludge treatment control unit 31 described above. The sludge treatment control unit 31 is based on the sludge supply flow rates Q1 to Q3 detected by the flow meters 12, 18, and 23 and the sludge concentrations C1 to C3 detected by the concentration meters 13, 17, and 21, respectively. The drive of each sludge supply pump 11, 16, and 22 is controlled so that the density | concentration of the mixed sludge produced | generated by 6 and the compounding ratio of primary sedimentation sludge and excess concentration sludge are settled in a predetermined range. Furthermore, based on the sludge concentration C4 detected by the fourth densitometer 30, the concentration of the concentrated sludge by the centrifugal concentrator 4 is adjusted.

  Specifically, the sludge treatment control in the sludge treatment control unit 31 is executed according to the sludge treatment routine shown in FIG. In addition, each sludge supply pump 11, 16, 22 is operating continuously. Therefore, the primary concentrated sludge stored in the primary concentrated sludge storage tank 2 and the excess concentrated sludge sent from the centrifugal concentrator 4 via the centrifugal concentrated sludge line 29 and stored in the excessive concentrated sludge storage tank 5 are: The first settling sludge supply pump 11 and the surplus concentrated sludge supply pump 16 are respectively drawn out, passed through the sludge lines 8 and 9, and flowed into the mixed sludge storage tank 6. The primary sedimentation sludge and excess concentrated sludge that have flowed into the mixed sludge storage tank 6 are mixed to form mixed sludge, drawn out by the mixed sludge supply pump 22, and sent to the sludge dehydrator 7 through the mixed sludge line 10.

  This sludge treatment routine is executed every predetermined calculation cycle (time cycle). First, in step S1, the mixed sludge concentration C3 which is the concentration of the mixed sludge extracted from the mixed sludge storage tank 6 detected by the third densitometer 21. Is read. Then, it progresses to step S2 and the primary sediment concentration sludge of the mixed sludge produced | generated in the mixed sludge storage tank 6, the excess concentrated sludge, and a mixture ratio are estimated.

  This mixing ratio is estimated by interposing the sludge lines 8 and 9 through which the first settling sludge and surplus concentrated sludge, which are continuously supplied to the mixed sludge storage tank 6 by the operation of the two sludge supply pumps 11 and 16, pass. From the history of the supply flow rates Q1 and Q2 and the concentrations C1 and C2 measured over time by the first and second flow meters 12 and 18 and the first and second concentration meters 13 and 17, The excess concentrated sludge weights g1 and g2 are calculated.

g1 = Q1, C1, S
g2 = Q2 ・ C2 ・ S
(However, S is the time required to reach the amount of mixed sludge stored in the mixed sludge storage tank 6. In addition, when Q1, C1, Q2, and C2 change in the meantime, (The integrated value for each unit time during the time S may be obtained.)
And the compounding ratio g1 / g2 of the primary sedimentation sludge in the mixing sludge storage tank 6 and a surplus concentration sludge is estimated from this weight g1, g2. The process in this step corresponds to the mixed sludge property calculating means of the present invention.

  Next, the process proceeds to step S3, and a difference (concentration difference) ΔC between the preset target concentration Co and the mixed sludge concentration C3 is calculated (ΔC = Co−C3). In step S4, a difference (mixing ratio difference) Δε between a preset target blending ratio εo and an estimated blending ratio g1 / g2 is calculated (Δε = εo− (g1 / g2)). In the present embodiment, the target concentration Co is set to 3 [%], for example, and the target blend ratio εo is set to, for example, g1 / g2 = 90/100.

  Then, it progresses to step S5, according to density | concentration difference (DELTA) C and mixing | blending ratio difference (DELTA) epsilon, supply flow rate Q1 of the primary sedimentation sludge supply pump 11 which approaches the target density | concentration Co and the target mixing | blending ratio (epsilon) o, and the surplus concentration sludge supply pump 16 Is set within the range of the pumping capacity (upper limit, lower limit) of each sludge supply pump 11, 16.

  As shown in FIG. 4A, for example, when the mixed sludge concentration C3 is lower than the target concentration Co, the mixed sludge concentration C3 is equal to the target concentration Co ± α with a slope set according to the concentration difference ΔC. The concentration-based supply flow rates Qc1 and Qc2 are set so as to fit in the region with time. As shown in FIG. 4B, for example, when the estimated blending ratio g1 / g2 is higher than the target blending ratio εo ± β, the estimated blending ratio is set according to the blending ratio difference Δε. The blending ratio main supply flow rates Qε1 and Qε2 are set so that g1 / g2 is within the target blending ratio εo ± β region with time. Then, as shown in FIG. 4C, the estimated blending ratio g1 / g2 and the concentration C3 are controlled so as to be within a preset region M in consideration of the weight.

Thereafter, the process proceeds to step S6, and the ratios of the mixture ratio main supply flow rates Qε1, Qε2 and the concentration main supply flow rates Qc1, Qc2 are set according to the weight indicating the priority between the concentration and the mixture ratio. For example, when the weight is 70 (concentration): 30 (combination ratio), the concentration main supply flow rates Qc1, Qc2 are 0.7Qc1, 0.7Qc2, and the mixture ratio main supply flow rates Qε1, Qε2 are 0.3Qε1. , 0.3Qε2, and the supply flow rate of the first sedimentation sludge supply pump 11 is
(0.7Qc1 + 0.3Qε1) / 2
Set with. Also, the supply flow rate of the excess concentrated sludge supply pump 16 is
(0.7Qc2 + 0.3Qε2) / 2
Set with. The processes in steps S4 to S6 correspond to the sludge supply amount calculating means of the present invention.

  And it progresses to step S7 and compares the supply flow rate of both the concentrated sludge supply pumps 11 and 16 set according to the weight in step S6 with the current supply flow rates Q1 and Q2 measured by the first and second flow meters, respectively. Then, it is checked whether or not it falls within a preset range, that is, whether or not it is balanced. If not, the process returns to step S5, and again the supply flow rate of the initial sedimentation sludge supply pump 11 and The supply flow rate of the excess concentrated sludge supply pump 16 is set.

  On the other hand, when the supply flow rates of both the concentrated sludge supply pumps 11 and 16 and the current supply flow rates Q1 and Q2 measured by the first and second flow meters are within the preset range, the process proceeds to step S8. A drive signal corresponding to the supply flow rate set in step S6 described above is output to the concentrated sludge supply pumps 11 and 16, and the supply flow rates of the two concentrated sludge supply pumps 11 and 16 are changed.

  Then, it progresses to step S9, it waits until the density | concentration C1 of the initial sedimentation sludge measured with the 1st flow meter 12 fluctuates more than the preset width | variety, and when the density | concentration C1 fluctuates, each concentrated sludge supply pump 11 newly. , 16 to exit the routine in order to recalculate the supply flow rates of the primary sedimentation sludge and excess concentrated sludge. In addition, the said routine can be controlled so that a mixture ratio and a density | concentration always approach a target value according to the state of the mixed sludge currently stored in the mixed sludge storage tank 6 by repeating for every predetermined time.

  Thus, in this embodiment, it is thrown into the mixed sludge storage tank 6 based on the concentrations C1 and C2 of the primary sedimentation sludge and excess concentrated sludge flowing into the mixed sludge storage tank 6 and the supply flow rates Q1 and Q2. The mixing ratio g1 / g2 between the first settling sludge and the excess concentrated sludge is estimated, and the concentration C3 in the mixed sludge storage tank 6 is measured with the third concentration meter 21, and the concentration C3 and the estimated mixing ratio g1 / Since the supply flow rate of primary sedimentation sludge and excess concentrated sludge is adjusted so that g2 is within the specified range, mixed sludge storage can be performed using existing equipment without adding a new system. It is economical because the concentration and mixing ratio of the first settling sludge and excess sludge flowing into the tank can be controlled appropriately.

  In addition, since the concentration and mixing ratio of primary sludge and excess sludge are appropriately controlled, the amount of flocculant added during dehydration and the amount of fuel used when burning mixed sludge can be suppressed. Better economics can be obtained.

  In addition, this invention is not restricted to embodiment mentioned above, For example, you may make it variably set the density | concentration C2 of excess concentration sludge with the centrifugal concentrator 4. FIG.

1 ... Water treatment equipment,
2 ... Initial sedimentation sludge storage tank,
2a ... Sludge interface meter,
3 ... Surplus sludge storage tank,
4 ... Centrifugal concentrator,
5 ... Surplus concentrated sludge storage tank,
6 ... Mixed sludge storage tank,
6a ... Water level gauge,
7 ... sludge dewatering machine,
8 ... Initial sedimentation sludge line,
9 ... Surplus concentrated sludge line,
10 ... Mixed sludge line,
11 ... Initial sedimentation sludge supply pump,
12 ... 1st flow meter,
13 ... first concentration meter,
16 ... Surplus concentrated sludge supply pump,
17 ... second densitometer,
18 ... second flow meter,
21 ... The third densitometer,
22 ... Mixed sludge supply pump,
23. Third flow meter,
26 ... Surplus sludge line,
27 ... Surplus sludge supply pump,
28a, 28b ... inlet valve,
29 ... centrifugal concentration sludge line,
30 ... Fourth concentration meter 31 ... Sludge treatment control unit,
C1 ... Initial sediment concentration sludge concentration,
C2 ... Surplus concentrated sludge concentration,
C3 ... Mixed sludge concentration,
Co: Target concentration,
Q1-Q3 ... Supply flow rate,
Qc1, Qc2 ... Concentration-based supply flow rate,
Qε1, Qε2 ... mixing ratio main supply flow rate,
g1, g2 ... weight,
g1 / g2 ... Estimated blending ratio,
ΔC: Concentration difference,
Δε: Mixing ratio difference,
εo ... Target compounding ratio,

Claims (4)

The primary sedimentation sludge stored in the primary sedimentation sludge storage tank and the surplus concentration sludge stored in the surplus concentration sludge storage tank are extracted and supplied to the mixed sludge storage tank.
In the sludge treatment method in a water treatment facility, the mixed sludge stored in the mixed sludge storage tank is dehydrated by extracting and dewatering the mixed sludge of the excess concentrated sludge.
The concentration of the initial settling sludge and the supply flow rate to the mixed sludge storage tank, and the concentration of the excess concentrated sludge and the supply flow rate to the mixed sludge storage tank are detected over time, and the mixed sludge storage tank Estimating the blending ratio of the stored primary sedimentation sludge and excess concentrated sludge,
Find the mixed sludge concentration that is the concentration of the mixed sludge drawn out from the mixed sludge storage tank,
The mixed sludge concentration and the blending ratio are compared with the preset target mixed sludge concentration and the target blending ratio so that the mixed sludge concentration and the blending ratio approach the target mixed sludge concentration and the target blending ratio. A sludge treatment method in a water treatment facility, wherein a supply flow rate of the initial settling sludge and the excess concentrated sludge to the mixed sludge storage tank is controlled. The mixed sludge concentration is compared with the target mixed sludge concentration, and the primary sludge concentration sludge and the surplus concentrated sludge are mainly concentrated in the mixed sludge storage tank to bring the mixed sludge concentration close to the target mixed sludge concentration. Find the supply flow rate
Comparing the blending ratio with the target blending ratio, the blending ratio main supply flow rate to the mixed sludge storage tank of the primary sedimentation sludge and the excess concentrated sludge for bringing the blending ratio close to the target blending ratio. Seeking each
Based on the concentration main supply flow rate and the mixing ratio main supply flow rate of the primary sedimentation sludge, the supply flow rate of the primary sedimentation sludge to the mixed sludge storage tank is set to the priority of the mixed sludge concentration and the mixing ratio. And determining the supply flow rate of the excess concentrated sludge to the mixed sludge storage tank based on the concentration main supply flow rate and the mixing ratio main supply flow rate of the excess concentrated sludge. The sludge treatment method in the water treatment facility according to claim 1, wherein the sludge treatment method is determined according to priority. An initial sedimentation sludge storage tank for storing an initial sedimentation sludge that has concentrated the primary sedimentation sludge;
A surplus concentrated sludge storage tank for storing surplus concentrated sludge obtained by concentrating surplus sludge discharged after sludge treatment;
A mixed sludge storage tank that mixes and stores the primary sedimentation sludge and the excess concentrated sludge;
A sludge dewatering machine for dewatering the mixed sludge of the initial settling sludge and the excess concentrated sludge stored in the mixed sludge storage tank;
A first sludge feeding means for extracting the primary sedimentation sludge stored in the primary sedimentation sludge storage tank and feeding it to the mixed sludge storage tank;
A second sludge feeding means for extracting the surplus concentrated sludge stored in the surplus concentrated sludge storage tank and feeding it to the mixed sludge storage tank;
A third sludge feeding means for extracting the mixed sludge stored in the mixed sludge storage tank and feeding it to the sludge dehydrator;
First concentration detecting means for detecting the concentration of the initial sedimentation sludge;
First flow rate detection means for detecting the flow rate of the first sludge concentration sludge supplied by the first sludge feed means to the mixed sludge storage tank;
Second concentration detecting means for detecting the concentration of the excess concentrated sludge;
Second flow rate detection means for detecting a flow rate of the surplus concentrated sludge supplied by the second sludge feed means to the mixed sludge storage tank;
A third concentration detecting means for detecting the mixed sludge concentration;
Third flow rate detection means for detecting the flow rate of the mixed sludge fed by the third sludge feed means to the sludge dehydrator;
Control means for controlling the flow rates of the first sludge feeding means and the second sludge feeding means for supplying to the mixed sludge storage tank;
The control means obtains the mixed sludge concentration by the third concentration detection means, and detects by the first concentration detection means, the first flow rate detection means, the second concentration detection means, and the second flow rate detection means. Based on the history of each concentration and flow rate, the mixed sludge property calculating means for estimating the blending ratio of the primary settled sludge and the excess concentrated sludge in the mixed sludge storage tank,
The mixed sludge concentration detected by the third concentration detecting means and the mixing ratio estimated by the mixed sludge property calculating means are compared with the preset target mixed sludge concentration and target mixing ratio, and the mixed sludge concentration and the Sludge supply amount calculation means for setting the flow rates of the first sludge feed means and the second sludge feed means for bringing the blend ratio close to the target mixed sludge concentration and the target blend ratio, respectively. A sludge treatment device in a water treatment facility. The sludge supply amount calculating means compares the mixed sludge concentration detected by the third concentration detecting means with the target mixed sludge concentration, and makes the mixed sludge concentration approach the target mixed sludge concentration. Obtain the concentration main supply flow rate to the mixed sludge storage tank of the primary sedimentation sludge and the excess concentrated sludge,
The mixing ratio of the mixed sludge to the target mixing ratio, and the mixing ratio of the primary sedimentation sludge and the excess concentrated sludge to the mixed sludge storage tank in order to make the mixing ratio close to the target mixing ratio Find the main supply flow rate,
Based on the concentration main supply flow and the mixing ratio main supply flow of the initial settling sludge, the supply flow rate to the mixed sludge storage tank of the initial settling sludge is preset with the mixed sludge concentration and the mixing ratio. The supply flow rate of the surplus concentrated sludge to the mixed sludge storage tank is determined based on the concentration main supply flow rate and the mixing ratio main supply flow rate of the surplus sludge concentration, and the mixed sludge concentration and The sludge treatment apparatus in a water treatment facility according to claim 3, wherein the sludge treatment apparatus is determined according to a preset priority of the blending ratio.