JP6103231B2 - Method and system for dewatering sewage sludge - Google Patents

Description

The present invention selectively recovers only fibrous materials suitable as a dewatering aid from inflow water flowing into a sewage treatment plant, and adds the recovered dewatering aid to the hardly dewatered sludge generated in the sewage treatment process. The present invention relates to a method and a dehydration system.

Conventionally, hardly dewatered sludge generated in a sewage treatment plant has a low fiber content and poor dewaterability. In anaerobic digestion sludge treatment, dewatered sludge such as digested sludge obtained by decomposing organic matter (fiber content, etc.) in sludge by the action of anaerobic bacteria and surplus sludge converted to microorganisms is dehydrated. Therefore, fiber content is reduced in the sludge before dehydration. Since the fiber content in the sludge functions as a core of coagulation and has the effect of forming a water channel during dehydration, sludge with a reduced fiber content cannot perform proper coagulation, resulting in poor dewaterability. .

A method of dehydrating by mixing a fiber material or a plant material such as sawdust or rice husk into a hardly dewatered sludge as a dehydrating aid has been known for a long time and has been practiced in many treatment plants. When a fibrous material is used as a dehydration aid, a dehydrated cake with a low water content can be obtained, and in the case of pressure dehydration, the peelability of the dehydrated cake is improved. However, since a large amount of dehydration aid has to be prepared and supplied, running costs increase, and there is a problem that storage and supply facilities for the dehydration aid have to be installed.

Thus, a technique for separating and recovering fibers in raw sludge generated from the first sedimentation basin of the sludge treatment process and adding the recovered fibers to hardly dewatered sludge such as excess sludge or digested sludge and dehydrating is disclosed in Citation 1. ing.

Further, Cited Document 2 discloses a sludge management system that manages the dewatering treatment of sludge that is dehydrated by adding a dewatering auxiliary material to the sludge supplied to the dewatering equipment.

JP-A 61-268400 JP 2012-206018 A

Since the technique of the cited document 1 collects fiber from the sludge in the treatment plant, it is not necessary to prepare a separate dehydration aid, and the running cost and equipment are the same as those in normal treatment. However, in a separation device using a screen or a vibrating screen mesh as disclosed in the specification, as a dehydration aid for easily decomposable organic substances derived from food residues entangled with fiber components (persistent organic substances) Inappropriate things cannot be separated and collected together with the fiber content. Therefore, when fibers entangled with easily decomposable organic substances, most of which are moisture, are added as a dehydrating aid, the amount of dehydrated cake increases and the processing cost increases. In addition, since the readily decomposable organic matter decomposes and decays after dehydration, the dehydration aid before addition and the dehydrated cake after addition cannot be stored for a long period of time. A specific method for recovering only the effective fiber as a dehydrating aid has not been disclosed, and it has been difficult to recover only the necessary fiber.

The technology of Cited Document 2 is based on the sludge information of the treatment plant and the manufacturing information of the auxiliary material supply device that manufactures the dehydration auxiliary material fiberized from unnecessary paper sheets installed in the office or the like. It manages logistics information for supplying to the dehydration facility, and flexibly supplies an appropriate amount of dehydration auxiliary material from the dehydration auxiliary material supply device to the dehydration facility at an appropriate time. However, it is necessary to install an auxiliary material supply device that dissolves paper sheets to produce dehydration auxiliary materials in offices, etc., and the amount of unnecessary paper sheets used as raw materials for dehydration auxiliary materials is not constant. An auxiliary material supply device must be installed in the office. In addition, a distribution means for transporting the dehydration auxiliary material from the office to the treatment plant is required.

The present invention predicts the amount of dewatering aid recovered and separated from a sewage treatment process in a predetermined period, predicts the amount of sludge to be dehydrated while keeping the amount of dewatering aid stored to a minimum, Provided is a dewatering method and a dewatering system for sewage sludge that distributes and supplies dewatering aids in an amount.

The dewatering method of the sewage sludge of the present invention is a method of collecting fibers in the inflow water flowing into the sewage treatment plant, supplying the hardly dewatered sludge resulting from the sewage treatment process as a dewatering aid, and dehydrating with a dehydrator. Estimated total recovery amount of dewatering aid from the sludge information, which is information about the actual amount of dewatering aid collected in advance and the content of dewatering aid in the inflowing water that varies depending on the season, day of the week, and weather. The estimated total sludge amount to be dehydrated by the dehydrator is estimated from the actual sludge amount of sludge flowing into the sewage treatment plant and sludge information, and the predicted total recovered amount is distributed and supplied to the predicted total sludge amount. The storage period is short, the supply amount does not fluctuate extremely, and a stable dehydrated cake with a low water content can be generated.

The dewatering system for sewage sludge of the present invention includes a collection device for collecting dewatering aid, a measuring device for measuring the amount of dewatering aid collected, a measuring device for measuring the amount of sludge to be dehydrated, and dewatering aid as sludge. And a control device for adjusting the supply amount of the supply device. The control device has a predetermined period set in advance, and the actual recovery amount of the dehydration aid and the inflow that varies depending on the season, day of the week, and weather. Calculate the predicted total recovery amount of the dewatering aid to be separated and recovered from the sludge information, which is information on the content of the dewatering aid in the water, and calculate the predetermined amount from the actual sludge amount and sludge information of the sludge flowing into the sewage treatment plant. Calculate the predicted total sludge amount to be dehydrated by the dehydrator during the period and calculate the supply amount to distribute the predicted total recovery amount to the predicted total sludge amount. Supplied based on predicted recovery volume and dehydrator operating time while forecasting Since calculating the while with the variation of the recovery amount, a stable supply amount can be supplied to the flame dewatered sludge.

Since the control device calculates the supply amount for evenly distributing the predicted total recovered amount with respect to the predicted total sludge amount, it is possible to generate a dehydrated cake having a stable low water content. Moreover, the same effect can be acquired even if the supply amount for distributing an actual collection amount equally with respect to an actual sludge amount is calculated.

The dewatering method and system of the sewage treatment plant of the present invention collects the dewatering aid from the sewage treatment process, so there is no need to purchase a dewatering aid separately, and no inventory management, supply facilities, etc. are required. Since the hardly decomposable organic substance (fibrous substance) is recovered as a dehydration aid in the previous stage of the sewage treatment process, the decomposition efficiency in the digester is improved. Since the collected dewatering aid is sequentially supplied in accordance with the operating time of the dehydrator, the storage period becomes short, the dewatering aid storage facility can be reduced, and alteration, decay, and odor generation can be prevented. Predicting the amount of dewatering aid collected for a given period, the supply amount is calculated from the predicted amount collected and the operating time of the dehydrator, so the dewatering cake has a stable and low water content without excessive fluctuation. Can be obtained.

It is a flowchart of the system which concerns on this invention. Similarly, it is a flowchart after a collection device. Similarly, it is the collection data of the dewatering aid at the sewage treatment plant. Similarly, it is the flowchart of other Example 1. FIG. Similarly, it is the flowchart of other Example 2. FIG.

The dewatering method and dewatering system for sewage sludge according to the present invention predicts the total recovered amount 11 of dewatering aid recovered from sludge (including sewage) generated from the sewage treatment process within a predetermined period CP, and total sludge to be dewatered. The purpose is to predict the amount 23 and distribute and add the predicted total recovery amount 13 according to the predicted total sludge amount 25 to improve the dewaterability of the sludge and minimize the storage amount of the dewatering aid.

FIG. 1 is a flowchart of a system according to the present invention. First sedimentation basin 1 that separates the inflow water that has flowed into the sewage treatment plant, reaction tank 2 that purifies organic matter in the sewage separated in the first sedimentation basin 1, and gravity that concentrates the raw sludge separated in the first sedimentation basin 1 A concentration tank 35, a recovery device 3 for selectively separating and recovering the dewatering aid by drawing out a predetermined amount of raw sludge in the previous stage of the gravity concentration tank 35, a final sedimentation tank 20 for separating the mixed liquid in the reaction tank 2, Mechanical concentration tank 36 for concentrating excess sludge separated in final sedimentation basin 20, digestion tank 37 for anaerobically digesting gravity concentrated sludge and mechanical concentrated sludge, and sludge storage tank for temporarily storing non-dewaterable digested sludge 27 and a dehydrator 8 that separates sludge mixed with dewatering aid and digested sludge into solid and liquid.

The position for extracting the sludge for collecting the dewatering aid is not limited as long as it is the first stage of the gravity concentration tank 35 such as the first sedimentation tank 1 or the flow path before and after the first sedimentation tank 1. Moreover, you may add a polymer flocculent to the sludge which mixed the dehydration auxiliary material and digested sludge as needed. As the dehydrator 8, a known dehydrator such as a screw press, a belt press, or a centrifugal dehydrator can be used.

Since sewage flows into the sewage treatment plant every day for 24 hours, the sludge precipitated with sewage is transferred to the recovery device 3 to recover the dewatering aid in the sludge. A collection amount of the dehydration aid collected within a predetermined continuous predetermined period CP is defined as a total collection amount 11. The amount of inflow to the sewage treatment plant varies depending on the season, day of the week, and weather, and the content of dewatering aid contained in the sludge also varies. Such information is accumulated as sludge information 26 in the treatment plant including past information. The total recovery amount 11 that will be recovered within the predetermined period CP is predicted from the measured value of the recovery amount of the dehydration aid several times during the predetermined period CP and the sludge information 26. The measured value of the collected amount is set as the actual collected amount 12, and the predicted value of the total collected amount 11 is set as the predicted total collected amount 13.

The residue after the dehydration aid has been collected within the predetermined period CP is concentrated, returned to the digestion tank 37 and subjected to anaerobic digestion, and then dehydrated by the dehydrator 8. Here, the dehydrator 8 is not operated every day in the sewage treatment plant. The operating time of the dehydrator 8 is determined as needed according to the amount of sludge generated from the sewage treatment process. Since the amount of sludge fluctuates, the total amount of sludge 23 that will be dehydrated within the predetermined period CP is predicted from the initial measured value of the predetermined period CP and the sludge information 26. The measured value of the sludge amount is the actual sludge amount 24, and the predicted value of the total sludge amount 23 is the predicted total sludge amount 25. In general, the dehydrator 8 is operated only at a predetermined date and time when a supervisor is engaged according to the predicted total sludge amount 25.

Although storage of the dewatering aid extracted from the sludge is indispensable, it is desirable to reduce the storage capacity as much as possible in view of the arrangement and space in the treatment plant. Therefore, the recovery amount of the dewatering aid separated and recovered from the sludge generated in the sewage treatment process in the predetermined period CP and the sludge amount dehydrated by the dehydrator 8 are accurately predicted, and the dewatering aid storage amount 29 is kept below a certain level. It is important to calculate the supply amount 14 so that the total recovery amount 11 can be distributed and supplied according to the total sludge amount 23 while being held.

The dewatering aid recovered from sewage sludge is a hardly decomposable organic substance mainly composed of plant-like fibrous materials. For example, toilet paper dissolved in sewage is a hardly decomposable organic substance. In addition, the hardly dewatered sludge is sludge whose fiber content which is a core of aggregation is greatly reduced by biological treatment or the like and the dewaterability is deteriorated. For example, digested sludge produced in the digestion tank 37, OD excess sludge produced in the reaction tank 19 of the OD method, and the like are hardly dewatered sludge. The sludge after extraction of the hard-to-decompose organic matter is mainly composed of easy-to-decompose organic matter, but the easy-to-decompose organic matter from the food residue is easily spoiled and cannot be stored for a long period of time. And anaerobic digestion. In the digestion tank 37, since the hardly decomposable organic substances are reduced due to the collection of the dehydration aid, the reaction period in the digestion process can be shortened, which contributes to the improvement of the treatment efficiency of the entire treatment plant.

Toilet paper does not dissolve even when dipped in water, and the fibers constituting the sheet form are only unwound and dispersed. Therefore, a large amount of fiber derived from toilet paper is present in the sewage sludge.

In the present invention, since the fiber content in the sludge is used as a dehydration aid, the fiber content in the inflow water flowing into the sewage treatment plant is extracted by the recovery device 3. The recovered fiber is added to the hardly dehydrated sludge before agglomeration and functions as a nucleus of agglomeration. If a dehydrating aid having an appropriate property is added to the sludge, a strong coagulated floc is formed and the dehydrating property is improved.

FIG. 2 is a flowchart after the collection device according to the present invention. The sludge precipitated and separated from the sewage flowing into the sewage treatment plant is drawn out and transferred to the recovery device 3. The recovery device 3 selectively separates the hardly decomposable organic matter in the sludge and discharges it to the auxiliary material storage tank 4. The easily decomposable organic matter that is not recovered in the auxiliary material storage tank 4 is transferred from the recovery device 3 to the digestion tank 37 via the gravity concentration tank 35. In the auxiliary material storage tank 4, the recovery amount of the dewatering auxiliary material is measured by a known measuring device 15 such as a weight meter or a level meter. The measurement data of the actual recovery amount 12 of the collected dewatering aid is sequentially transmitted to the control device 16, and the control device 16 calculates the predicted total recovery amount 13 predicted to be recovered within the predetermined period CP. The predicted total recovery amount 13 is corrected and corrected every time measurement data of the actual recovery amount 12 is transmitted.

Digested sludge is temporarily stored in the sludge storage tank 27. In the sludge storage tank 27, the amount of sludge is measured by a known measuring device 28 such as a level meter. The stored measurement data of the actual sludge amount 24 is sequentially transmitted to the control device 16, and the control device 16 calculates a predicted total sludge amount 25 predicted to be stored within the predetermined period CP. The predicted total sludge amount 25 is corrected and corrected every time measurement data of the actual sludge amount 23 is transmitted. The measuring device 28 for measuring the amount of sludge may be disposed in the sludge transfer pipe, or the amount of sludge may be estimated from the dewatered cake discharged from the dehydrator 8 .

The control device 16 calculates the dehydration aid supply amount 14 based on the predicted total recovery amount 13 and the predicted total sludge amount 25. The dehydration aid supply device 5 is controlled according to the calculated supply amount 14. At this time, the storage amount 29 in the auxiliary material storage tank 4 is input to the control device 16 in advance so as to be limited within a predetermined range.

When the dehydration aid is supplied to the hardly dehydrated sludge by the supply device 5, if the dilution water 17 is injected, the dehydration aid is easily transferred.

FIG. 3 shows the collection data of the dewatering aid at the sewage treatment plant. There is an inflow of sewage containing organic matter every day for 24 hours in the sewage treatment plant, and a predetermined amount of sludge is first extracted from the settling basin 1 and transferred to the recovery device 3. However, it can be seen that the sludge concentration varies greatly depending on the season and date and time, especially on Saturday and Sunday holidays, the sludge concentration is low, and the amount of solids is halved compared to the weekdays from Monday to Friday. Therefore, the recovery amount of the dehydration aid mainly composed of fiber, which is a hardly decomposable organic substance, is also decreasing.

In this treatment plant, an easily decomposable organic substance that is not suitable as a dehydration aid is anaerobically digested in the digestion tank 37, and then the digested sludge is dehydrated by the dehydrator 8. In this treatment plant, the digested sludge is not drawn out from the digestion tank 37 in order to minimize the amount of inflow on Saturday and Sunday so as to minimize the operation of the dehydrator. Therefore, the amount of digested sludge generated on Saturday and Sunday is 0 in the data.

In this treatment plant, due to the amount of sludge and the processing capacity of the dehydrator 8, the operation is only 8 hours each on weekdays, and the operation is stopped on holidays. The supply amount 14 of the dewatering aid is calculated so that the total recovered amount 11 of the dewatering aid can be supplied uniformly in accordance with the total sludge amount 23 during the predetermined period CP. In this data, the total recovery amount 11 of the dewatering aid recovered in one week is supplied to the total sludge amount 23 to be dehydrated in that week at an equal addition rate.

<Amount collected>
The proposed embodiment will be described in detail with reference to the data of FIG. A predetermined period CP for collecting the dehydration aid was set as follows.
Predetermined period: 7 days from Saturday to Friday

About the sludge generated in the water treatment process, the raw sludge is extracted from the first settling basin 1 of the sewage treatment plant and transferred to the recovery device 3. The operation of pulling out a predetermined amount every certain time may be performed several times, or the entire amount may be pulled out continuously.

The recovered hardly decomposable organic matter is stored in the auxiliary material storage tank 4 as a dehydrating auxiliary material. A recovery amount of the dewatering aid stored in the auxiliary material storage tank 4 is measured in real time by a known measuring device 15, and measurement data of the actual recovery amount 12 is transmitted to the control device 16. Diluent water 17 may be poured into the auxiliary material storage tank 4 in accordance with the actual recovery amount 12 of the dehydrating auxiliary material. In this embodiment, the dilution water 17 is poured until the concentration becomes 3%.

The control device 16 calculates the predicted total recovery amount 13 of the dewatering aid that can be recovered in the predetermined period CP with reference to the actual recovery amount 12 and the sludge information 26 such as past measurement information and weather information. In order to accurately predict the predicted total recovery amount 13, measurement data of the actual recovery amount 12 is transmitted to the control device 16 at any time, and the control device 16 calculates the predicted total recovery amount 13 while correcting it.

In this embodiment, the collection of the dehydration aid is started from Saturday. As shown in FIG. 3, the amount of dewatering aid collected decreases on Saturday and Sunday holidays. This is because there are many office districts in the inflow area of the dredged sewage treatment plant from which this data was extracted, and the amount of sludge inflow from the office district is reduced on Saturdays and Sundays when ordinary offices are closed. Conversely, in sewage treatment plants with inflow areas centering on residential areas, the concentration of inflow sludge is expected to increase on Saturdays and Sundays, and the amount of dewatering aid recovered will increase.

In the recovery device 3, only the hardly decomposable organic matter in the extracted sludge is separated and recovered and stored in the auxiliary material storage tank 4. The residue (mainly easily decomposable organic matter) extracted from the hardly decomposable organic matter is returned to the digestion vessel 37 through the gravity concentration tank 35 disposed at the first stage of the settling basin 1 and anaerobic digestion according to the sewage treatment process. To do.

<Sludge volume>
In this embodiment, the sludge to be dewatered is stored in the sludge storage tank 27. The amount of sludge stored in the sludge storage tank 27 is measured in real time by a known measuring device 28, and the measurement data of the actual sludge amount 24 is transmitted to the control device 16.

The control device 16 calculates the predicted total sludge amount 25 generated in the predetermined period CP with reference to the actual sludge amount 24 and the sludge information 26 such as past measurement information and weather information. In order to accurately predict the predicted total sludge amount 25, the measurement data of the actual recovery amount 12 is transmitted to the control device 16 as needed, and the control device 16 calculates the predicted total sludge amount 25 while correcting it.

Similar to the recovered amount, the amount of sludge generation on the soil and Sunday is small, so the dehydrator 8 performs the dehydration process only for 5 days from Monday to Friday. The dehydrator 8 uses a screw press 18 that can be continuously dehydrated.

<Calculation of supply amount>
In order to evenly distribute and supply the dewatering aid of the predicted total recovery amount 13 calculated by the control device 16 to the sludge of the predicted total sludge amount 25 calculated by the control device 16, the supply amount 14 of the dehydration aid by the control device 16 Is calculated. In this embodiment, since the period for collecting the dewatering aid and the period for storing the sludge are completely the same, the dewatering aid is always based on the predicted total recovery amount 13 and the predicted total sludge amount 25 of the latest data. The supply amount 14 is calculated at any time. After calculating the dehydration aid supply amount 14, the control device 16 adjusts the dehydration aid supply device 5 to mix the dehydration aid supply device 5 with the predetermined amount of the hardly dehydrated sludge.

The actual recovered amount 12 may be evenly distributed and supplied to the actual sludge amount 24 to be dehydrated during the predetermined period CP.

If the amount of solids flowing into the sewage treatment plant increases, the amount of dewatering aid that can be recovered from it also increases. At this time, since easily decomposable organic substances that are not suitable for the dewatering aid are also increasing, the amount of sludge to be dewatered by the dehydrator 8 is also increased. Although the predicted total recovery amount 13 of the dewatering aid collected in the auxiliary material storage tank 4 tends to increase, the predicted total sludge amount 25 to be dehydrated also tends to increase, and the supply amount of the dehydration aid also increases. Therefore, since the storage amount 29 of the auxiliary material storage tank 4 does not increase extremely, the auxiliary material storage tank does not require a large space.

Conversely, if the amount of solids flowing into the sewage treatment plant decreases, the amount of recovered dewatering aid that can be recovered therefrom also decreases. At this time, since easily decomposable organic substances that are not suitable as a dewatering aid have also decreased, the amount of sludge to be dewatered by the dehydrator 8 also decreases. Although the predicted total recovery amount 13 of the dewatering aid collected in the auxiliary material storage tank 4 tends to decrease, the predicted total sludge amount 25 to be dehydrated also tends to decrease, and the supply amount of the dehydration aid also decreases. Therefore, since the storage amount 29 of the auxiliary material storage tank 4 does not cause an extreme decrease in the storage amount, there is no shortage of dehydration auxiliary material and the dehydration process with an unstable moisture content is not caused.

FIG. 4 is a flowchart of another embodiment 1, and is a flowchart when the first settling basin is not installed in the sewage treatment plant. Specifically, the treatment method when employing the OD method or MBR (membrane separation activated sludge method) is applicable. The inflow water flowing into the treatment plant flows into the reaction tank 19 and is purified by the action of microorganisms. A part of the inflow water is introduced into the solid-liquid separator 21 branched from the reaction tank inflow passage to separate suspended substances in the sewage. The washing waste water is transferred to the recovery device 3. The filtered water is returned to the inflow side of the front stage of the reaction tank 19. The dewatering aid is selectively separated and recovered from the wastewater such as suspended substances transferred to the recovery device 3. The gravity concentration tank 35 concentrates surplus sludge transferred from the final sedimentation tank 20 and residues such as easily decomposable organic substances returned from the recovery device 3. The supernatant liquid of the gravity concentration tank 35 is sent to the inflow side before the reaction tank 19. The residue discharged from the recovery device 3 may be returned to the reaction tank 19. The dewatering surplus sludge and the like concentrated in the gravity concentration tank 35 is mixed with the dewatering aid recovered by the recovery device 3, and if necessary, a polymer flocculant is added, and the dehydrator 8 performs the dewatering treatment. I do.
In addition, when MBR is employ | adopted, the final sedimentation tank 20 becomes unnecessary, the supernatant liquid of the reaction tank 19 is discharged | emitted as treated water, and sludge is transferred to the gravity concentration tank 35. FIG.

FIG. 5 is a flowchart of another embodiment 2, and is a flowchart for processing mixed raw sludge obtained by mixing raw sludge from the first sedimentation basin and excess sludge from the final sedimentation basin. Specifically, the flow excluding the digester shown in FIG. In general, since the amount of inflow of sewage is reduced at night than in the daytime, the amount of sludge withdrawn from the settling basin 1 is reduced. Therefore, since the ratio of the excess sludge sent from the final sedimentation basin 20 increases, the mixed sludge becomes difficult to dehydrate. Therefore, the dewatering efficiency is improved by employing the dewatering system of the present invention for dewatering the mixed raw sludge.
The flow relating to the dewatering aid is the same as in FIG. 1, and the dewatering aid is extracted from the raw sludge drawn out from the settling basin 1 by the recovery device 3. Residues such as readily decomposable organic matter discharged from the recovery device 3 are returned to the gravity concentration tank 35 and mixed with gravity concentrated sludge (raw sludge) and mechanically concentrated sludge (excess sludge) and dehydrated by the dehydrator 8. The A dehydrating aid is added to the mixed raw sludge before the dehydrator 8.

The dewatering method and dewatering system for sewage sludge according to the present invention is to effectively utilize the fiber content as dewatering aid from sludge obtained by settling and separating sewage flowing into the sewage treatment plant. It can be done. Not only will running costs be reduced, but because the amount of dewatering aid is used while predicting the amount of dewatering aid that is predicted, it is possible to reduce the size of equipment such as the storage tank for dewatering aid. it can.
Effectively used for sludge treatment in sludge system as a dewatering aid, and added to the hardly dewatered sludge generated in the treatment system, and can produce a stable low moisture content dehydrated cake. Thus, an environment-friendly dewatering method and dewatering system that makes dewatering cake processing inexpensive and easy can be obtained.

3 Recovery device 5 Supply device 8 Dehydrator 12 Actual recovery amount 13 Predicted total recovery amount 14 Supply amount 15, 28 Measuring device 16 Control device 24 Actual sludge amount 25 Predicted total sludge amount 26 Sludge information CP Predetermined period

Claims (4)

In the method of recovering the fiber content of the inflow water flowing into the sewage treatment plant, supplying it to the hardly dewatered sludge resulting from the sewage treatment process as a dehydration aid, and dehydrating with the dehydrator (8),
At a predetermined period (CP),
From the actual recovery amount of dewatering aid (12) and the sludge information (26), which is information about the content of the dewatering aid in the inflowing water that varies depending on the season, day of the week, and weather, the predicted total recovery amount of dewatering aid (13 )
Estimate the predicted total sludge amount (25) to be dewatered by the dehydrator (8) from the actual sludge amount (24) and sludge information (26) of the sludge flowing into the sewage treatment plant,
A dewatering method of sewage sludge, characterized by distributing and supplying a predicted total recovery amount (13) to a predicted total sludge amount (25). In the system that collects the fiber content of the inflow water flowing into the sewage treatment plant, supplies it to the hardly dewatered sludge resulting from the sewage treatment process as a dehydration aid, and dehydrates it with the dehydrator (8).
A recovery device (3) for recovering the dehydration aid;
A measuring device (15) for measuring the amount of dewatering aid recovered;
A measuring device (28) for measuring the amount of sludge to be dehydrated;
A supply device (5) for supplying dewatering aid to sludge;
A control device (16) for adjusting the supply amount (14) of the supply device (5),
The control device
In a predetermined period (CP) set in advance,
The total amount of dewatering aid to be separated and recovered from the actual amount of dewatering aid (12) and the sludge information (26), which is information about the content of dewatering aid in the influent that varies depending on the season, day of the week, and weather. Calculate the recovery amount (13)
From the actual sludge amount (24) of the sludge flowing into the sewage treatment plant and the sludge information (26), the predicted total sludge amount (25) to be dehydrated by the dehydrator (8) during a predetermined period is calculated.
A dewatering system for sewage sludge, characterized in that a supply amount (14) for distributing a predicted total recovered amount (13) to a predicted total sludge amount (25) is calculated. The controller is
The sewage sludge dewatering system according to claim 2, wherein a supply amount (14) for uniformly distributing the predicted total recovery amount (13) to the predicted total sludge amount (25) is calculated. The controller is
The sewage sludge dewatering system according to claim 3, wherein a supply amount (14) for evenly distributing the actual recovery amount (12) to the actual sludge amount (24) is calculated.

Images