JP4633770B2 - Sludge dewatering system - Google Patents

Description

  The present invention relates to a sludge dewatering system for dewatering a sludge to produce a dehydrated sludge having a low water content, in which a flocculant solution is added to the sludge and then dewatered by a sludge dewatering machine.

  Conventionally, when sewage such as sewage is purified with a sewage treatment device, various types of sludge such as primary sludge, surplus sludge, digested sludge, etc. are generated. Disposal is not easy. Therefore, in general, these sludges (hereinafter, to be treated sludge) are subjected to a dehydration process in which the sludge is separated into a dehydrated sludge and a separated liquid by a sludge dehydrator. In addition, sludge to be treated is a mixture of suspended particles and water, and these suspended particles aggregate to form sludge flocs and become larger (flocced), and almost all aggregates. Without being present as fine suspended particles. If the sludge to be treated is dewatered as it is with a sludge dewatering machine, fine suspended particles that are not flocked flow out to the separation liquid side, and the properties of the separation liquid (turbidity, foaming status, chromaticity, etc.) deteriorate and separation performance Is low. For this reason, the flocculant is usually supplied to and added to the sludge to be treated to increase the size of the sludge floc, and then the dewatering process is performed by the sludge dehydrator.

  Patent Document 1 discloses an example of a sludge treatment apparatus (sludge dewatering system) using a centrifugal dewatering machine (sludge dewatering machine). The sludge treatment apparatus of Patent Document 1 is configured to transfer raw sludge (treated sludge) stored in a sludge tank to a centrifugal dehydrator and perform solid-liquid separation into a separated liquid and a dehydrated cake with the centrifugal dehydrator. Injecting inorganic flocculant (inorganic flocculant solution) into the sludge being transferred, and then injecting amphoteric polymer (amphoteric polymer flocculant solution) to promote the formation of sludge flocs, followed by solid-liquid separation with a centrifugal dehydrator It is a device to do. In addition, this sludge treatment apparatus is equipped with a pH meter that measures the pH of the separation liquid and a chromaticity meter that measures the chromaticity of bubbles in the separation liquid. According to these measured values, the inorganic flocculant and the amphoteric The amount of the two types of polymer flocculants injected into the treated sludge is controlled.

  Also in Patent Document 2, a first flocculant (inorganic flocculant solution) made of a metal salt is added to sludge (treated sludge) and stirred, and further a second flocculant made of a cationic or amphoteric polymer flocculant. A method of dewatering sludge in which (cationic or amphoteric polymer flocculant solution) is added and stirred and then dehydrated with a dehydrator is shown. In any case, after adding an inorganic flocculant solution to the treated sludge and adjusting the pH of the treated sludge, the polymer flocculant solution is added to promote the formation of sludge flocs. ing.

  Usually, the fine suspended particles in the sludge to be treated often have negatively charged surfaces, and the negatively charged suspended particles act to repel each other. This repulsive force is greater than the intermolecular force, which is the force that attracts molecules, and this is one factor that prevents the formation of sludge flocs. When an inorganic flocculant solution is injected into the sludge to be treated, electrons on the surface of suspended particles are taken away, the negative charge is neutralized, intermolecular force is easy to work, and fine suspended particles form small sludge flocs. To come. Furthermore, by adding the polymer flocculant solution to the treated sludge, the polymer chains adhere to the small sludge flocs, and the polymer chains are cross-linked to increase the size of the sludge flocs. By subjecting the treated sludge thus treated to dehydration treatment with a sludge dehydrator, a dehydrated sludge having a low water content and a separated liquid having good properties can be obtained. In both Patent Document 1 and Patent Document 2, the inorganic flocculant has a large element that is supplied to the treated sludge in order to assist the flocculant action of the polymer flocculant.

  On the other hand, recently, the performance of cationic polymer flocculants and amphoteric polymer flocculants has been greatly improved, and the sludge to be treated can be treated without adjusting the pH by adding an inorganic flocculant solution to the treated sludge. Polymer flocculants that can be neutralized by adsorbing cationic groups to the negative charge on the surface of fine suspended particles have been developed. For this reason, the case where the sludge dehydration system which inject | pours only these polymer flocculants with respect to a to-be-processed sludge, forms sludge floc, and dehydrates with a sludge dehydrator is increasing.

JP-A-8-71600 Japanese Patent Laid-Open No. 10-230300

  The quality of sewage, which is raw water flowing into a sewage treatment system that purifies sewage such as sewage by biological treatment, is not always constant, but varies from day to day or from hour to hour. Therefore, primary sludge generated in these wastewater treatment system also varies properties such as excess sludge. Moreover, the property of the digested sludge which processed these sludge in the fermenter also fluctuates. When these sludges are treated as sludge and are dehydrated by a sludge dewatering system, the change in the properties of the treated sludge greatly affects the ease with which sludge flocs are formed. Depending on the situation, a sludge floc can be formed sufficiently by simply injecting a small amount of the flocculant solution into the treated sludge, or a sludge floc can be sufficiently formed unless a large amount of the flocculant solution is injected into the treated sludge. It may not be done. For this reason, in a normal sludge dewatering system, the moisture content of the dewatered sludge and the properties of the separated liquid, which are the results of the dewatering treatment by the sludge dewatering machine, are confirmed visually or by actual measurement, and the flocculant solution coating is determined according to those results. This can be done by adjusting the amount injected into the treated sludge.

  By the way, the coagulant solution supplied to the sludge to be treated is more cohesive with sludge suspended material particles (formation of sludge flocs) when using an expensive coagulant with high coagulation performance than with an inexpensive coagulant with low coagulation performance. Tend to be promoted. However, expensive flocculants with high flocculation performance are not absolutely effective. Rather, the application of a flocculant suitable for the properties of the treated sludge supplying the flocculant solution further promotes the formation of sludge flocs. In order to cope with the sludge to be treated of various properties, a storage tank equipped with a conventional stirrer is prepared for each type of flocculant, and a flocculant solution is generated in each storage tank. leave reservoir Te, nor no configuration is also considered that supplies to choose suits flocculant solution at that time. However, since the flocculant has the following characteristics, even if such a configuration is applied, it becomes very inefficient and unrealistic.

  In general, the flocculant is manufactured and sold in a state of being packed in a solid form (hereinafter referred to as a granular form) such as a granular form or a powder form. And it keeps in the state of bag packing, and when using it, it is made to melt | dissolve in water and is used as a flocculant solution. This is because the aggregating agent has a performance in which the aggregating performance deteriorates with time when left in a state dissolved in water. Particularly in the case of the polymeric coagulant, aggregation ability to a level which can not be used as a flocculant solution in a few days is reduced. Moreover, most of the flocculants having high flocculant performance are polymer flocculants. For this reason, if many kinds of flocculant solutions as described above are stored, the flocculant performance decreases before it is used up, and a large amount of flocculant solution that does not become useful is generated, which greatly increases the running cost. It becomes bulky.

  Further, the flocculant such as particulates does not dissolve in water in a short time. Conventionally, when a flocculant solution is produced from a granular flocculant, a flocculant solution tank having a flocculant supply machine for supplying granular flocculant, a dissolved water supply pipe for supplying dissolved water, and a stirrer is provided. Use. Supply the dissolved water and flocculant to produce a flocculating agent solution with a predetermined concentration in the flocculant solution tank, stir and mix with a stirrer, dissolve the flocculant over time, and flocculant solution A flocculant solution is produced in the bath. In particular, when the flocculant to be applied is a polymer flocculant, it takes several hours to dissolve. Granular polymer flocculants are solidified in a state where polymer chains are entangled, and in order to dissolve in water, the surface layer of the particles absorbs water and swells, and the polymer chains peel into water This is because water passes through the inner layer (second layer) and swells by being absorbed, and the polymer chain of the inner layer is peeled off in order, so that it passes through the process of dissolving to the center such as granular form. For this reason, many kinds of flocculants are stored in a granular state or the like having a long storage period, and when supplied to the treated sludge, the flocculant solution is generated in short time and supplied. Is extremely difficult in a storage tank equipped with a conventional stirrer.

  Therefore, conventionally, the sludge to be dewatered with a sludge dewatering machine is frequently sampled in advance, and a flocculant with a wide range of application that can obtain an average dewatering performance for these sludges to be treated is selected. It was. The selected flocculant is stored as a flocculant solution in a large-capacity storage tank as in the past, and is appropriately supplied to the treated sludge. Moreover, when the property of the to-be-processed sludge has changed a little, the coagulating action was complemented by increasing the supply amount of the coagulant solution. In selecting a highly versatile flocculant, not only the water content of the dewatered sludge dehydrated by the sludge dehydrator and the properties of the separated liquid, but also cost-effectiveness is emphasized.

  However, in the event of an emergency in which the properties of the treated sludge have changed abruptly compared to normal times, the dewatering performance does not improve and the formation of sludge flocs does not progress with the flocculant solution with a wide application range, no matter how much the supply amount is increased. As a result, the water content of the dewatered sludge is not sufficiently lowered, and the properties of the separated liquid may be lowered. In such a situation, even if a process for adjusting the pH of the treated sludge by adding an inorganic flocculant as described in Patent Document 1 or Patent Document 2 to the treated sludge is added, it is difficult to supplement the weak intermolecular forces of grains pollution, it has been a problem.

  In the case of polymer flocculants, in addition to solids such as granules, there are also concentrated liquids (emulsion state), but even in the concentrated liquid state, the polymer chains are entangled and conventional stirring The flocculant solution tank equipped with a machine is mixed with dissolved water and stirred and mixed, so that it can be dissolved in a shorter time than a polymer flocculant such as a granular form to produce a flocculant solution. It was difficult to say that it was possible to respond immediately when the properties changed, which was a problem. Furthermore, the concentrated liquid polymer flocculant deteriorates in a short time compared to solid particles such as granules, and the storage period is also short, as in the case of a sudden change in the properties of the sludge to be treated. It was difficult to say that it was suitable for use only in an emergency.

  On the other hand, due to the convenience of the treatment plant to be dewatered, when multiple types of sludge to be treated are dehydrated by the same sludge dewatering system, or to be treated sludge generated from a plurality of facilities where the sewage treatment system is installed, 1 In some cases, the wastewater is collected at a certain dewatering treatment plant and processed in a lump, but usually the treated sludge generated from each sewage treatment system has different properties. In these cases, the amount of the flocculant solution injected into the treated sludge is adjusted in view of the properties of the treated dewatered sludge and the properties of the separation liquid. Moreover, even if it is the to-be-processed sludge extracted from the same place in the same sludge dehydration system, a property changes with the date and time with which it was extracted. Even when this treated sludge is dehydrated by the sludge dewatering system, the amount of the flocculant solution injected into the treated sludge is adjusted by looking at the properties of the treated dewatered sludge and the properties of the separated liquid.

  However, even in these cases, it is difficult to exhibit the coagulation performance for various sludges by changing the injection amount with one type of coagulant, and to make the moisture content of the dewatered sludge below a predetermined value. depending on the type of processing the sludge there is a case dehydration of the dewatered sludge is insufficient, it has been a problem.

  The present invention has been made to solve the above-described problems, and is a sludge dewatering system that performs a dewatering process in which a sludge to be treated into which a flocculant solution has been injected is separated into a separation liquid and a dewatered sludge by a sludge dewatering machine. Even when the properties of the sludge to be treated change drastically or when various types of sludge are dehydrated as treated sludge, the moisture content of the prescribed dewatered sludge and the properties of the separated liquid are maintained within the prescribed ranges. It aims at providing the sludge dehydration system which can be done.

In order to solve the above-mentioned problems, a sludge dehydrator for separating the treated sludge into a separating liquid and a dewatered sludge, a sludge dewatering step comprising a sludge supply pipe for supplying the treated sludge to the sludge dewaterer, a coagulant and a dissolution agent The flocculant solution generated from water is stirred and mixed with a flocculant different from the flocculant in the first flocculant supply step and the first flocculant supply step for supplying the flocculant solution to the treated sludge through the flocculant solution supply pipe. A flocculant solution tank for generating a flocculant solution, a cylindrical container, a cylindrical screen disposed in the cylindrical container, and one or more pressing members disposed in the cylindrical screen; A holding member that holds the pressing member, and a drive unit that moves the pressing member along the inner surface of the cylindrical screen via the holding member, and the screen uses the flocculant solution introduced from the flocculant solution tank. While filtering, I and a second coagulant supply step of the flocculant solution discharged from the coagulant dissolver and coagulant dissolver which dissolves the flocculant solution in with a coagulant solution supply pipe for supplying the object to be processed sludge Ri, characterized that you supply a flocculant solution in both the first coagulant supply step or first coagulant supply step and the second coagulant supply process to be treated sludge.

  The sludge dewatering system according to claim 2 of the present invention is characterized in that the coagulant solution supply pipe in the first coagulant supply process and the coagulant solution supply pipe in the second coagulant supply process are joined together.

The sludge dewatering system according to claim 3 of the present invention is a viscometer that measures the viscosity of the flocculant solution that has flowed out of the flocculant dissolver, and the drive that starts and raises at a low speed according to the measured value of the viscometer. And a controller for controlling the rotation of the machine .

According to the sludge dewatering system according to the present invention, the sludge is supplied to the sludge dewatering machine through the sludge supply pipe, and the sludge dewatering step for separating the sludge into the dehydrated sludge and the separated liquid, and the flocculant solution is generated from the flocculant and the dissolved water. The flocculant solution is supplied to the sludge to be treated by the flocculant solution supply pipe, and the flocculant and dissolved water are stirred and mixed in the flocculant solution tank to produce the flocculant solution. And a second flocculant supply step of dissolving the flocculant in the flocculant solution and dissolving the flocculant in the flocculant solution and supplying the flocculant solution to the sludge to be treated by the flocculant solution supply pipe. There are the following effects.
(1) A flocculant solution having a wide application range that is normally used is supplied to the treated sludge by the first flocculant supplying step, and the first flocculant supplying step used when the properties of the treated sludge are rapidly changed. It is possible to supply an emergency coagulant solution having a different kind and characteristics from the coagulant to the sludge to be treated by the second coagulant supply process. As a result, the flocculant having a wide range of application can be stirred and mixed with dissolved water in a large-capacity flocculant solution tank to dissolve undissolved particles such as granules and stored in the flocculant solution tank. The required amount can be supplied to the treated sludge. The emergency coagulant is usually stored without being dissolved in dissolved water. In an emergency, the coagulant is stirred and mixed in a small volume coagulant solution tank together with dissolved water for a short time. A flocculant solution containing undissolved flocculant (hereinafter referred to as undissolved particles) is generated, and the flocculant solution is screen filtered with a flocculant dissolver to capture the undissolved particles of flocculant with the screen. Then, the undissolved particles are dissolved and dissolved in the flocculant solution, whereby a flocculant solution sufficiently dissolved in a short time can be generated and supplied to the treated sludge when necessary. Normally, a necessary amount of flocculant solution with a wide range of application can be supplied according to the properties of the treated sludge to promote the formation of sludge flocs of suspended particles in the treated sludge. In the case of a sudden change, an emergency coagulant solution can be generated and supplied to the treated sludge in a short time to promote sludge floc formation. Thereby, there exists an effect which can maintain the moisture content of the dewatered sludge after dewatering a to-be-processed sludge with a sludge dehydrator, and the property of a separated liquid in a predetermined range.
(2) The coagulant for emergency needs to be preliminarily dissolved in dissolved water in a large-capacity coagulant solution tank equipped with a conventional stirrer to generate and store the coagulant solution. Therefore, the coagulant performance of the emergency coagulant solution will deteriorate over time, and the properties of the treated sludge will not change so much until it becomes unusable as a coagulant solution. There is an effect that it is possible to avoid waste that is discarded without being used up.
(3) The flocculant for normal use and emergency can be stored without dissolving with dissolved water, and when necessary, the flocculant is agglomerated with undissolved particles sufficiently dissolved in dissolved water in a short time. Since the agent solution can be generated, there is an effect that the emergency coagulant can be stored for a long time while the coagulation performance is high.
(4) A flocculant solution having a wide application range is supplied to the sludge to be treated in the first flocculant supply step, and fine suspended particles in the sludge to be treated are aggregated to some extent to form small sludge flocs. In the coagulant supply process, an emergency coagulant solution can be injected into the sludge to be treated, and small sludge flocs that have been coagulated to some extent can be aggregated to promote the formation of large sludge flocs. As a result, even if an expensive flocculant is applied to the emergency flocculant supplied to the treated sludge when the property of the treated sludge to be dewatered changes suddenly, the emergency flocculant solution While reducing the supply amount, the moisture content of the dewatered sludge and the turbidity of the separated liquid can be maintained within a predetermined range, and the running cost can be suppressed.
(5) When sludge of different types, such as primary sludge, surplus sludge, digested sludge, etc., is treated with the same sludge dewatering system as treated sludge, or treated sludge generated from a sewage treatment system that purifies different raw water is 1 Even in the case of batch treatment with the sludge dewatering system at the location, depending on the type and properties of the treated sludge to be treated, a flocculant solution having a wide range of application in the first flocculant supply step is used in the second flocculant supply step. In the case of dewatering the sludge to be treated of any kind and property by supplying the emergency coagulant solution having different types and characteristics from the flocculant in the first flocculant supply step, the dewatered sludge The water content and the properties of the separation liquid can be maintained within a predetermined range, and the running cost applied to the flocculant can be suppressed as much as possible.
Further, the flocculant dissolving machine in the second flocculant supply step is arranged such that a cylindrical screen is arranged in a cylindrical container, the flocculant solution is introduced into the cylindrical screen from the flocculant solution tank, and the screen is filtered. By moving one or two or more pressing members along the inner surface of the cylindrical screen through the holding member, the flocculant (undissolved particles) adhering to the inner surface of the cylindrical screen is pressed and dissolved. There is an effect that the undissolved particles of the flocculant that cannot be completely dissolved can be surely dissolved by simply stirring and mixing the flocculant such as particles and dissolved water in a flocculant tank in a short time. In particular, there is a great effect when a polymer flocculant that is not easily dissolved in dissolved water is applied to the flocculant in the second flocculant supply step.

The sludge dewatering system according to the invention of claim 2 has the following effects.
(1) Since the flocculant solution supply pipe in the first flocculant supply process and the flocculant solution supply pipe in the second flocculant supply process are joined and connected, two kinds of flocculant solutions are mixed and various characteristics are obtained. A flocculant solution having the same can be produced. For example, when a chemical reaction occurs by mixing, the composition of the flocculant changes, and the neutralization action of the negative charge of the sludge suspended material is strengthened, the adsorption performance of the polymer yarn to the sludge suspended material The resulting flocculant solution has a cohesive performance as compared to the case where the two types of flocculant are separately supplied to the treated sludge, such as when the cross-linking between polymer yarns is strengthened. There is a dramatic improvement effect. Moreover, there exists an effect which can supply the flocculant solution of an optimal characteristic with respect to the to-be-processed sludge of various properties.
(2) A polymer flocculant having a wide application range is applied to the first flocculant supply step, and the second flocculant supply step is different in type and characteristics from the flocculant in the first flocculant supply step. A molecular flocculant is applied, and at normal times, an appropriate amount of a polymer flocculant solution having a wide application range from the first flocculant supply step can be supplied to the sludge to be treated for dehydration. When the property of the sludge to be treated changes suddenly, the polymer flocculant for emergency in the second flocculant supply step is stirred and mixed with the dissolved water for a short time by the flocculant solution tank, and the flocculant dissolver is used. The undissolved particles of the polymer flocculant can be dissolved to produce an emergency polymer flocculant solution, mixed with the polymer flocculant solution having a wide range of application, and supplied to the treated sludge. In this way, the distribution state in the coagulant solution in which the polymer chain of the polymer coagulant for emergency and the polymer chain of the polymer coagulant having a wide range of application is mixed is made uniform, and then the sludge to be treated is treated. Therefore, there is no variation and it is possible to promote the formation of sludge flocs on average.

According to the sludge dewatering system according to the invention described in claim 3, the viscometer that measures the viscosity of the flocculant solution dissolved by the flocculant dissolver , and starts at a low speed according to the measured value of the viscometer. By providing the controller for controlling the rotation of the driving machine to be raised , the following effects can be obtained.

Embodiment 1 FIG.
FIG. 1 is a flow diagram of the sludge dewatering system according to the first embodiment, FIG. 2 is a cross-sectional view along line AA of the coagulant dissolver, and FIG. 3 is a cross-sectional view along line BB of the coagulant dissolver. It is. The sludge dewatering system according to Embodiment 1 includes a sludge dewatering machine 1 that separates treated sludge into a separating liquid and dewatered sludge, and a sludge dewatering process that includes a sludge supply pipe 2 that supplies the treated sludge to the sludge dewatering machine 1. And flocculant solution tanks 4A and 4B that produce a flocculant solution by stirring and mixing the flocculant and dissolved water, and a flocculant solution supply pipe that supplies the flocculant solution to the treated sludge (hereinafter referred to as first flocculant). A first flocculant supply step having 5), a flocculant solution tank 6 for producing a flocculant solution by stirring and mixing the flocculant and dissolved water, and introducing the flocculant solution into the screen. The flocculant dissolver 8 that dissolves the flocculant in the flocculant solution and the flocculant solution supply pipe (hereinafter referred to as the second flocculant solution supply pipe) that supplies the flocculant solution flowing out from the flocculant dissolver 8 to the treated sludge. This is called a flocculant solution supply pipe. It is mainly composed of a second coagulant supply process with.

  The sludge dewatering machine 1 is a centrifugal dewatering machine, and the sludge supply pipe 2 connected to the sludge inlet of the sludge dewatering machine 1 is provided with a sludge supply pump 3 for supplying the sludge to be treated to the sludge dewatering machine 1. It has been. In addition to the centrifugal dehydrator, a belt press dehydrator, a screw press dehydrator, a rotary pressure dehydrator or the like can be applied to the sludge dehydrator 1. In addition, as a sludge dehydrator in a broad sense, a flotation concentrator, a centrifugal concentrator, or the like is also applicable.

  The flocculant solution tanks 4A and 4B in the first flocculant supply process supply so-called granular flocculants (hereinafter referred to as first flocculants) such as granules and powders to the flocculant solution tanks 4A and 4B. Coagulant supplying machines 10A and 10B, dissolved water supply pipes 12A and 12B for supplying dissolved water for dissolving the first coagulant to the coagulant solution tanks 4A and 4B, the first coagulant and the dissolution Stirrers 14A and 14B for stirring and mixing water are provided, and a flocculant solution (hereinafter referred to as a first flocculant solution) is generated by stirring and mixing the first flocculant and dissolved water by the stirrers 14A and 14B. It is supposed to be. The flocculant supply machines 10A and 10B include hopper-like containers 101A and 101B having flocculant supply ports 102A and 102B at the lower ends, and supply port switches 103A and the like having drive units disposed in the flocculant supply ports 102A and 102B. 103B. The supply port switches 103A and 103B may have any structure as long as the flocculant supply ports 102A and 102B can be controlled to open and close, such as a slide shutter structure, a flapper valve structure, a butterfly valve structure, and a meshing gear structure. Good. The flocculant supply ports 102A and 102B are liable to infiltrate the moisture vaporized in the flocculant solution tanks 4A and 4B, so that the flocculant particles may be solidified. It is desirable to maintain a dry state. The dissolved water supply pipes 12A and 12B are provided with control valves 13A and 13B, and the dissolved water is supplied into the flocculant solution tanks 4A and 4B via these control valves 13A and 13B. As the dissolved water, in addition to tap water, ground water, industrial water, filtered water, rainwater use water, reclaimed water, and the like can be applied, and any water that can dissolve the first flocculant such as the above-described particles may be used.

  An inorganic flocculant and a polymer flocculant are applicable as the flocculant supplied from the flocculant feeders 10A and 10B to the flocculant solution tanks 4A and 4B. The inorganic flocculant, polyaluminum chloride, ferric polysulfate, ferric chloride, aluminum sulfate, aluminum chloride, and the like. The polymer flocculant includes amphoteric polymers such as methacrylic acid ester (eg, dimethylaminoethyl methacrylate) and acrylic acid ester (eg, dimethylaminoethyl acrylate), such as dimethyl acrylate. Examples include copolymers of aminoethyl and acrylic acid. Any agent can be applied as long as it is a granular agent having an action of promoting aggregation of suspended particles in the treated sludge.

  The first flocculant solution supply pipe 5 that supplies the first flocculant solution generated in the flocculant solution tanks 4A and 4B to the sludge to be treated in the sludge supply pipe 2 is provided in each of the flocculant solution tanks 4A and 4B. The flocculant solution tanks 4A and 4B are connected to the downstream side of the sludge supply pump 3 of the sludge supply pipe 2. Open / close control valves 15 and 16 are provided in the branch pipe portions 5A and 5B, respectively. Further, a solution pressure pump 17 is provided on the downstream side of the junction portion of the branch pipe portions 5A and 5B in the first flocculant solution supply pipe 5, and the solution pressure feed pump 17 allows the flocculant solution tanks 4A and 4B to be disposed. one of the first coagulant solution are supplied to the treated sludge sludge feed pipe 2.

  The flocculant solution tank 6 in the second flocculant supply step is a tank having a smaller capacity than the flocculant solution tanks 4A and 4B in the first flocculant supply step, and is different in type and characteristics from the first flocculant solution. A solution (hereinafter referred to as a second flocculant solution) of a flocculant (hereinafter referred to as a second flocculant solution) suitable for an emergency such as a case where the property of the treated sludge has changed abruptly compared to the normal time is generated. To do. The normal flocculant solution tank 6 is maintained in an empty state or only with dissolved water, and the flocculant supply tank in the first flocculant supply step is disposed above the flocculant solution tank 6. Similar to 10A and 10B, a flocculant supply machine 18 including a hopper-like container 180 having a flocculant inlet 181 and a supply port switch 182 is disposed. The flocculant supply machine 18 stores the second flocculant such as particles and supplies the second flocculant into the flocculant solution tank 6 only in the emergency. The flocculant solution tank 6 is supplied with dissolved water for dissolving the second flocculant from the dissolved water supply pipe 19 via the control valve 20 in the emergency, and the second flocculant and A stirrer 21 for stirring and mixing the dissolved water is provided.

    Here, as the first flocculant, for example, at least one flocculant of an inorganic flocculant and a polymer flocculant is applied, and the second flocculant is a coating that hardly exhibits a flocculant action with the first flocculant. properties of the treated sludge to apply polymeric flocculants to exhibit high cohesive performance in case of changes abruptly.

  The second flocculant solution generated in the flocculant solution tank 6 in the second flocculant supply step is a pump that is provided in the flocculant solution transfer pipe 7 that connects the flocculant solution tank 6 and the flocculant dissolver 8. By 22, it is pumped to the flocculant dissolver 8. Here, unlike the flocculant solution tanks 4A and 4B in the first flocculant supply step, the flocculant solution tank 6 in the second flocculant supply step has a small capacity and the second flocculant supplied into the tank. The dissolved water is stirred and mixed by a stirrer 21 for a relatively short time, and is sent to the flocculant dissolver 8 by the pumping force of the pump 22. For this reason, the second coagulant such as particles cannot be completely dissolved in the coagulant solution tank 6 and is sent to the coagulant dissolver 8 with the undissolved particles remaining. The pumping pump 22 may be any pump that can pump the coagulant solution, such as a centrifugal pump typified by a vortex pump and a positive displacement pump typified by a single screw pump. because this coagulant solution may contain undissolved grains considerable amount, the application of positive displacement pump is desirable.

  As shown in FIGS. 2 and 3, the flocculant dissolver 8 includes a cylindrical tubular container 80, a cylindrical screen 85 that is disposed in the tubular container 80 and filters the second flocculant solution, One or two or more pressing members 86 for dissolving undissolved particles of the flocculant adhering to the inner surface of the cylindrical screen 85, holding members 87A and 87B for holding both ends of the pressing member 86, and the holding members It has a structure including a drive unit 88 that moves the pressing member 86 along the inner surface of the cylindrical screen 85 through 87A and 87B.

  More specifically, the cylindrical container 80 has flange portions 80A and 80B at both ends, and flange lids 81A and 81B are bolts and nuts to the flange portions 80A and 80B via seal members (not shown). It is fixed by 82A and 82B. The outlet of the flocculant solution transfer pipe 7 is connected to a flocculant solution inlet 81C provided on one flange lid 81A. Further, on the inner peripheral surface of the cylindrical container 80, a pair of left and right annular partition members 83A and 83B that also serve as a screen holding member are provided. Both ends of the cylindrical screen 85 are supported by the partition members 83A and 83B. The inside of the cylindrical container 80 is divided into a primary chamber 84A and a secondary chamber 84B by partition members 83A and 83B and a cylindrical screen 85.

  The second flocculant solution that has flowed into the primary chamber 84A from the flocculant solution inlet 81C is filtered through the cylindrical screen 85 by the pressure feed force of the pressure feed pump 22 and then flowed into the secondary chamber 84B. From the flocculant solution outlet 80C provided in the cylindrical container 80 to the second flocculant solution supply pipe 9 to be merged with the first flocculant solution flowing through the first flocculant solution supply pipe 5. Yes. Accordingly, the flocculant solution outlet 80 </ b> C of the flocculant dissolver 8 is connected to the first flocculant solution supply pipe 5 on the downstream side of the solution pump 17 by the second flocculant solution supply pipe 9.

  The driving device 88 is disposed outside the flange lid 81B opposite to the flange lid 81A having the flocculant solution inlet 81C, and the driving shaft 88A of the driving device 88 extends to the center of the cylindrical screen 85 and has a tip portion. The flange lid 81A is supported via a bearing 89. The drive shaft 88A is provided with a pair of left and right holding members 87A and 87B that rotate integrally with the drive shaft 88A, and one or more parallel to the drive shaft 88A across the holding members 87A and 87B. (Four pieces in FIG. 2) are pivotally supported. These pressing members 86 circulate along the inner peripheral surface of the cylindrical screen 85 by the rotation of the drive shaft 88A, and undissolved particles in the second flocculant solution adhering to the inner surface of the cylindrical screen 85 are cylindrical screen. It melt | dissolves by pressing between 85 inner surfaces.

  The pressing member 86 includes a shaft portion 861 supported at both ends by the holding members 87A and 87B and a contact portion 862 that covers the outer peripheral surface of the shaft portion 861 and directly presses undissolved particles. The holding members 87A and 87B and a biasing member such as a spring are supported so as to be biased toward the cylindrical screen 85 side. Although the holding members 87A and 87B and the pressing member 86 are configured, the pressing member 86 may be configured to move in contact with the inner surface of the cylindrical screen 85. In this case, however, the pressing member 86 and the like are worn away. There is a risk of getting ahead. Since a thin film is formed on the inner surface of the cylindrical screen 85 by depositing undissolved particles when the second flocculant solution is screen filtered by the cylindrical screen 85, the pressing member 86 can press the thin film. Further, it is desirable that the cylindrical screen 85 be moved in a non-contact state because the problem of wear can be solved. The drive unit 88 incorporates a speed reducer 88B that decelerates the rotational speed of a power source such as an electric motor, and is transmitted to the drive shaft 88A via the speed reducer 88B. When the power source of the drive machine 88 is an electric motor, it is desirable to control the rotation speed with an inverter.

  In the above, the supply port switch 182 of the flocculant supply machine 18 in the second flocculant supply process, the control valve 20 of the dissolved water supply pipe 19, the stirrer 21, the pressure feed pump 22, and the driving machine 88 are controlled by the controller 23. It has come to be.

  Next, the operation of the sludge dewatering system in the first embodiment will be described. When the supply port switches 103A and 103B of the coagulant supply machines 10A and 10B and the control valves 13A and 13B of the dissolved water supply pipes 12A and 12B are opened in the first coagulant supply process, the coagulant solution tanks 4A and 4B are opened. The first flocculant is supplied from the flocculant supply machines 10A and 10B, and the dissolved water is supplied from the dissolved water supply pipes 12A and 12B. The first flocculant and the dissolved water are sufficient by the stirrers 14A and 14B. By stirring and mixing with time, a first flocculant solution that has been sufficiently dissolved is produced. The first flocculant solution is opened by the solution pressure feed pump 17 by opening one of the open / close control valves 15 and 16 of the first flocculant solution supply pipe 5 system (for example, opening the open / close control valve 15). 1 is fed to the sludge to be treated in the sludge supply pipe 2 through the coagulant solution supply pipe 5. When the first flocculant solution in the flocculant solution tank 4A becomes empty, the first flocculant solution tank 4B is stored by closing the open / close control valve 15 and opening the open / close control valve 16. In the flocculant solution tank 4A, the first flocculant solution is newly generated while supplying the agent solution to the treated sludge. In this way, the treated sludge to which the first flocculant solution has been added is supplied from the sludge supply pipe 2 to the sludge dewatering machine 1. Thereby, a 1st flocculant supply process is performed and the normal sludge dehydration process by the sludge dehydrator 1 is performed. Note that the flocculant solution tank 6 in the second flocculant supply step is empty (or only dissolved water is stored) during normal sludge dewatering treatment.

  When a facility manager or the like visually confirms that the properties of the treated sludge have changed abruptly compared to normal (emergency) during normal sludge dewatering treatment, the controller 23 is operated, 2. Activate the flocculant supply process. When the supply port switch 182 of the flocculant supply machine 18 in the second flocculant supply step is opened and the control valve 20 of the dissolved water supply pipe 19 is opened by the output signal from the controller 23, the empty state is obtained. In the flocculant solution tank 6, the second flocculant (polymer flocculant) having a high flocculation performance is supplied from the flocculant supply machine 18 and dissolved water is supplied from the dissolved water supply pipe 19. (If the inside of the flocculant solution tank 6 is not empty and only dissolved water is stored, the second flocculant is supplied in an amount corresponding to the amount of dissolved water stored. After that, supply of dissolved water from the dissolved water supply pipe 19 is started, and the concentration of the flocculant solution after the dissolution treatment varies depending on the ratio of the second flocculant and the amount of dissolved water supplied at this time. The concentration of the dissolved water is fixed to the dissolved water supply pipe 19. An amount valve and a flow rate control valve are provided to adjust the supply flow rate of the dissolved water to the flocculant solution tank 6 so that the supply amount of the second flocculant to the flocculant solution tank 6 per predetermined time is By controlling and changing the supply port switch 182, the concentration of the flocculant solution produced in the flocculant solution tank 6 can be freely adjusted, but the present invention is not limited to this method, and the flocculant solution is not limited to this method. Any method can be applied as long as the concentration of the agent solution can be adjusted.) The second flocculant and dissolved water supplied into the flocculant solution tank 6 are stirred and mixed for a short time by the stirrer 21 activated by the output signal from the controller 23. As a result, the second flocculant solution in which the undissolved particles generated in the flocculant solution tank 6 remain flows through the flocculant solution transfer pipe 7 by the pressure feed pump 22 and enters the cylindrical container 80 of the flocculant dissolver 8. Into the primary chamber 84A. The second flocculant solution that has flowed into the primary chamber 84 </ b> A passes through the cylindrical screen 85, and undissolved particles in the second flocculant solution are attached to and captured by the inner surface of the cylindrical screen 85 during the passage.

  Undissolved particles adhering to the inner surface of the cylindrical screen 85 are pressed between the inner surface of the cylindrical screen 85 by a pressing member 86 driven by a driving device 88 in a direction that circulates along the inner peripheral surface of the cylindrical screen 85. Then, the swollen portion of the undissolved particle surface layer is crushed to separate the polymer chains, and the separated polymer chains pass through the cylindrical screen 85 together with the second flocculant solution and flow into the secondary chamber 84B.

  The second flocculant solution that has flowed into the secondary chamber 84B flows out from the flocculant solution outlet 80C of the cylindrical container 80 to the second flocculant solution supply pipe 9 at a constant flow rate as long as the pump 22 is activated. To do. The second flocculant solution is supplied from the flocculant solution supply pipe 9 to the first flocculant solution in the first flocculant solution supply pipe 5. In this way, in the first flocculant solution supply pipe 5, the first flocculant solution and the second flocculant solution for emergencies having different types and characteristics are mixed, and the mixed flocculence is obtained. solution is injected from the first coagulant solution supply tube 5 to be treated sludge sludge feed pipe 2. At this time, the first flocculant solution and the second flocculant solution are mixed, but it is not simple mixing, and mixed flocculant solutions having various characteristics are generated depending on the types of the first flocculant and the second flocculant to be applied. The For example, when a chemical reaction occurs by mixing, the composition of the flocculant changes, and the neutralization action of the negative charge of the sludge suspended material is strengthened, the adsorption performance of the polymer yarn to the sludge suspended material The flocculating performance of the produced flocculant solution is greatly improved, for example, when the cross-linking bond between the polymer yarns is reinforced. Thereby, even if it is the to-be-processed sludge at the time of an emergency in which aggregation of sludge suspended solid particle is not accelerated | stimulated well only by supplying the normal 1st flocculant solution, this newly produced flocculant solution is supplied. Thus, the sludge suspended solid particles in the treated sludge can be agglomerated and supplied to the sludge dewatering machine 1 by a strong agglomeration action, so that the water content and separation of the dewatered sludge after dewatering can be efficiently performed. The properties of the liquid can be maintained within a predetermined range.

  In addition, although it is about the operation | movement method of a 2nd flocculant supply process, the water quality measuring device (not shown) which measures water quality, such as a turbidity of the separated liquid after spin-drying | dehydration processing by the sludge dehydrator 1, is installed. By connecting the water quality measuring instrument and the controller 23 with a signal line, automatic control for operating the second coagulant supply process can be performed when the properties of the separation liquid change abruptly to a predetermined value or more. Also good. The sludge dewatering system in the first embodiment as described above can be used, for example, as follows depending on the site environment where it is installed.

  In a sewage treatment system that purifies sewage by biological treatment, sludges having different properties (primary sludge, surplus sludge, digested sludge, etc.) are generated at each treatment stage. Although it is inherently desirable to install a dedicated sludge dewatering system for each type of sludge and perform dewatering treatment, it is actually difficult due to problems such as installation space. In many cases, a plurality of types of sludge are time-shared by one sludge dewatering system, supplied to the sludge dewatering machine 1 as a treated sludge, and dehydrated. For example, in FIG. 4, two types of sludge, surplus sludge and digested sludge, are time-shared as sludge to be treated and supplied to the sludge dewatering machine 1 in the sludge dewatering system. In FIG. 4, digested sludge is supplied to the sludge dewatering machine 1 as treated sludge from 18 hours to 6 hours and surplus sludge from 9 hours to 15 hours, respectively. It is difficult to instantaneously switch the type of sludge to be treated to be supplied to the sludge dewatering machine 1 due to problems such as the sludge supply pipe length. In the case of FIG. 4, from 6 hours to 9 hours and from 15 hours to 18 hours. In the meantime, mixed sludge in which excess sludge and digested sludge are mixed is supplied to the sludge dewatering machine 1 as treated sludge. For example, when the excess sludge is dehydrated, the first flocculant solution that is normally used is supplied to the excess sludge, and when the digested sludge is dehydrated, the second flocculant solution is also supplied and mixed with the first flocculant solution. Thus, the water content of the dewatered sludge can be maintained at a predetermined value or more by supplying the mixed flocculant solution with improved coagulation performance to the digested sludge. For mixed sludge, depending on the nature of the mixed sludge, select whether to supply only the first flocculant solution or the mixed flocculant solution with the second flocculant solution, and also regarding the mixing ratio, It is good to select while actually adjusting.

  On the other hand, due to problems of installation space and efficiency, the sludge dewatering system is not installed in the facility where the sewage treatment system is installed, and sludge generated from multiple sewage treatment systems is consolidated in one place. There exists a form which carries out the dehydration process collectively with one sludge dehydration system as the to-be-processed sludge. In this case, since the sludge is generated from a sewage treatment system that purifies different raw water, the properties of the sludge are often different in each sewage treatment system. The properties of the sludge to be treated by the sludge dewatering system are likely to change, and there is a large difference between sludge that tends to aggregate and sludge that does not easily aggregate. In the case of the properties of normal sludge to be treated, only the first flocculant solution is supplied to the sludge to be treated in the first flocculant supply step, and the dewatering process is performed by the sludge dehydrator 1. And when the property of the to-be-processed sludge changes rapidly, the 2nd flocculant solution is supplied, the mixed flocculant mixed with the 1st flocculant solution is supplied to the to-be-processed sludge, and it dehydrates with the sludge dehydrator 1. It is advisable to perform processing.

  In the sludge dewatering system of the first embodiment, a normal centrifugal dewatering machine is applied to the sludge dewatering machine 1, but an in-machine injection type centrifugal dewatering machine may be applied instead. In the case of a centrifugal dehydrator of the type that supplies the coagulant solution to the sludge to be treated in the normal sludge supply pipe 2 applied in the first embodiment, the coagulant action of the coagulant solution during transfer through the sludge supply pipe 2 When the treated sludge in which sludge flocs are formed is fed into the outer cylinder of a centrifugal dehydrator that rotates at high speed, the sludge flocs are destroyed by stirring with the acceleration force of high-speed rotation. Performance will be degraded. Usually, as a countermeasure, in order to re-form sludge flocs once collapsed in the outer cylinder, the supply amount of the flocculant solution to the treated sludge is previously excessively supplied more than necessary. As a result, it is possible to leave a flocculant that has not yet exhibited the coagulation action even after sludge flocs are formed in the sludge to be treated in the sludge supply pipe 2, and the treated sludge remains in the outer cylinder. When the sludge floc is supplied and the sludge floc is collapsed, the remaining flocculant exerts the aggregating action to form the sludge floc again, so that the dewatering performance in the centrifugal dehydrator can be maintained at a high level. However, this method has a problem that the running cost increases because it is necessary to supply the flocculant solution excessively.

  Was developed in order to solve such a problem is a flight injection type centrifugal dehydrator of. This centrifugal dehydrator has a double-pipe structure in which a sludge inflow pipe part is inserted into the outer cylinder and receives the treated sludge from the sludge supply pipe 2 and supplies it into the outer cylinder. It is said. In addition, a flocculant inflow port to which the first flocculant solution supply pipe 5 is connected is provided on the outer peripheral surface of the outer pipe at a portion not inserted into the outer cylinder, and the sludge to be treated flows into the inner pipe, A flocculant solution flows in the space between the outer tube. As a result, the sludge to be treated and the flocculant solution come into contact with each other when supplied to the outer cylinder, and are quickly mixed by the acceleration force of the outer cylinder, so that sludge flocs are formed there. The in-machine injection type centrifugal dehydrator has the effect that the running cost can be significantly reduced without excessive supply of the flocculant solution.

As described above, according to the sludge dewatering system in the first embodiment, the sludge dewatering step of supplying the sludge to be treated to the sludge dewatering machine 1 through the sludge supply pipe 2 and separating it into the dewatered sludge and the separated liquid, and the flocculant solution The first flocculant and dissolved water are stirred and mixed by the stirrers 14A and 14B in the tanks 4A and 4B to form the first flocculant solution, and the first flocculant solution supply pipe 5 treats the first flocculant solution. The first flocculant supply step for supplying the sludge, the second flocculant and the dissolved water are stirred and mixed by the stirrer 21 in the flocculant solution tank 6 to generate a second flocculant solution, and the second flocculant solution is The second flocculant is filtered by the flocculant dissolver 8 and the flocculant in the second flocculant solution is dissolved, and the second flocculant solution is supplied to the treated sludge by the second flocculant solution supply pipe 9. By comprising the supply process, the following effects are obtained.
(1) The 1st flocculant supply process used when the flocculant solution with the wide applicable application range normally used is supplied to a to-be-processed sludge by a 1st flocculant supply process, and the property of a to-be-processed sludge changes rapidly. It is possible to supply an emergency coagulant solution having different types and characteristics from the coagulant to the sludge to be treated by the second coagulant supply process. As a result, the highly versatile flocculant is stirred and mixed with dissolved water in the large-capacity flocculant solution tanks 4A and 4B over time to dissolve undissolved particles such as granules, and the flocculant solution tanks 4A and 4B. In normal times, the required amount can be supplied to the treated sludge. Further, the second flocculant for emergency is normally stored without being dissolved in the dissolved water, and the second flocculant is stored together with the dissolved water in a small capacity flocculant solution tank 6 in an emergency. The flocculant solution containing undissolved is produced by stirring and mixing for a period of time. Further, the flocculant solution is screen filtered by the flocculant dissolver 8, and the undissolved particles of the flocculant are captured by the screen 85. By dissolving and dissolving in the flocculant solution, a flocculant solution sufficiently dissolved in a short time can be generated and supplied to the treated sludge when necessary. Normally, a necessary amount of flocculant solution with a wide range of application can be supplied according to the properties of the treated sludge to promote the formation of sludge flocs of suspended particles in the treated sludge. In the case of a sudden change, an emergency coagulant solution can be generated and supplied to the treated sludge in a short time to promote sludge floc formation. Thereby, there exists an effect which can maintain the moisture content of the dewatered sludge after dewatering a to-be-processed sludge with a sludge dehydrator, and the property of a separated liquid in a predetermined range.
(2) The coagulant for emergency needs to be preliminarily dissolved in dissolved water in a large-capacity coagulant solution tank equipped with a conventional stirrer to generate and store the coagulant solution. Therefore, the coagulant performance of the emergency coagulant solution will deteriorate over time, and the properties of the treated sludge will not change so much until it becomes unusable as a coagulant solution. There is an effect that it is possible to avoid waste that is discarded without being used up.
(3) The flocculant for normal use and emergency can be stored without dissolving with dissolved water, and when necessary, the flocculant is agglomerated with undissolved particles sufficiently dissolved in dissolved water in a short time. Since the agent solution can be generated, there is an effect that the emergency coagulant can be stored for a long time while the coagulation performance is high.
(4) When sludge of different types, such as primary sludge, surplus sludge, digested sludge, etc., is treated with the same sludge dewatering system as treated sludge, or treated sludge generated from a sewage treatment system that purifies different raw water is 1 Even in the case of collective treatment with the sludge dewatering system at the location, depending on the type and properties of the treated sludge to be treated, a flocculant solution having a wide application range in the first flocculant supply step is used in the second flocculant supply step. In the case of dewatering the sludge to be treated of any kind and property by supplying the emergency coagulant solution having different types and characteristics from the flocculant in the first flocculant supply step, the dewatered sludge The moisture content and the properties of the separation liquid can be maintained within a predetermined range, and the running cost of the flocculant can be suppressed as much as possible.
(5) Since the flocculant solution supply pipe 5 in the first flocculant supply step and the flocculant solution supply pipe 9 in the second flocculant supply step are joined and connected, the two kinds of flocculant solutions are mixed and variously mixed. A flocculant solution having properties can be produced. For example, when a chemical reaction occurs by mixing, the composition of the flocculant changes, and the neutralization action of the negative charge of the sludge suspended material is strengthened, the adsorption performance of the polymer yarn to the sludge suspended material The resulting flocculant solution has a cohesive performance as compared to the case where the two types of flocculant are separately supplied to the treated sludge, such as when the cross-linking between polymer yarns is strengthened. There is a dramatic improvement effect. Moreover, there exists an effect which can supply the flocculant solution of an optimal characteristic with respect to the to-be-processed sludge of various properties.
(6) A polymer flocculant having a wide range of application is applied to the first flocculant supply step, and the second flocculant supply step is different in type and characteristics from the flocculant in the first flocculant supply step. A molecular flocculant is applied, and in normal times, an appropriate amount of a polymer flocculant solution having a wide application range from the first flocculant supply step can be supplied to the sludge to be treated to perform dehydration. Then, when the properties of the sludge to be treated change suddenly, the polymer flocculant for emergency in the second flocculant supply step is stirred and mixed together with the dissolved water by the flocculant solution tank 6 for a short time. In Step 8, the undissolved particles of the polymer flocculant are dissolved, a polymer flocculant solution for emergencies is generated, mixed with the polymer flocculant solution having a wide range of application, and supplied to the treated sludge. it can. In this way, the distribution state in the coagulant solution in which the polymer chain of the polymer coagulant for emergency and the polymer chain of the polymer coagulant having a wide range of application is mixed is made uniform, and then the sludge to be treated is treated. Therefore, there is no variation and it is possible to promote the formation of sludge flocs on average.
(7) In the flocculant dissolving machine 8 in the second flocculant supply step, a cylindrical screen 85 is disposed in the cylindrical container 80, and the flocculant solution is introduced into the cylindrical screen 85 from the flocculant solution tank 6. The screen is filtered, and one or more pressing members 86 are moved along the inner surface of the cylindrical screen 85 via the holding members 87A and 87B by the driving device 88, so that the flocculant adhering to the inner surface of the cylindrical screen 85 is not dissolved. By adopting a structure in which the particles are pressed and dissolved, the undissolved particles of the flocculant that cannot be completely dissolved can be surely obtained by simply stirring and mixing the flocculant such as particles and the dissolved water in the flocculant solution tank 6 in a short time. There is an effect that can be dissolved. In particular, there is a great effect when a polymer flocculant that is not easily dissolved in dissolved water is applied to the flocculant in the second flocculant supply step.
(8) In general, many flocculants exhibiting high flocculation performance with respect to the treated sludge having special properties are expensive. In the sludge dewatering system according to the first embodiment, an inexpensive coagulant having a wide range of application is applied to the first coagulant, and moderate coagulation performance is applied. When a flocculant exhibiting high flocculation performance is applied, the water content of the dewatered sludge dehydrated by the sludge dewatering machine 1 and the properties of the separation liquid are specified while reducing the amount of expensive flocculant used as much as possible. Since it can be maintained within the range, there is an effect that the running cost can be significantly reduced while being able to cope with the change in the properties of the sludge to be treated.

Embodiment 2. FIG.
FIG. 5 is a flowchart showing the sludge dewatering system in the second embodiment. The same parts as those in FIG. Further, since the flocculant dissolving machine 8 has the same structure as that of the first embodiment, the sectional view taken along the line AA in FIG. 2 and the sectional view taken along the line BB in FIG. The sludge dewatering system according to the second embodiment is different from the sludge dewatering system according to the first embodiment in that the first flocculant solution supply pipe 5 is joined to the second flocculant solution supply pipe 9. to differ greatly. In addition, the configuration and operation of the sludge dewatering system is substantially the same as in the first embodiment.

  As described above, according to the sludge dewatering system of the second embodiment, in addition to the various effects shown in the first embodiment, there are the following effects. In this sludge dewatering system, normally, only the first flocculant solution is supplied to the treated sludge by the first flocculant supply step, and when the property of the treated sludge changes suddenly, the second flocculant supply step 2 The flocculant is produced and mixed with the first flocculant solution, so that the mixed flocculant solution is supplied to the sludge to be treated, and the mixing ratio of the first flocculant solution and the second flocculant solution This makes it possible to produce mixed flocculant solutions having various characteristics. In the second embodiment, since the first flocculant solution supply pipe 5 is joined to the second flocculant solution supply pipe 9, the first flocculant solution and the second flocculant solution are mixed. When both are supplied, the second flocculant solution side is easier to flow. For this reason, when the mixed flocculant solution is generated, it is easy to increase the mixing ratio of the second flocculant solution, and when the properties of the mixed flocculant solution having a high mixing ratio of the second flocculant solution change more rapidly. In the case of effectively acting on the treated sludge, the configuration of the second embodiment is particularly effective.

Embodiment 3 FIG.
FIG. 6 is a flowchart showing the sludge dewatering system according to the third embodiment. The same parts as those in FIG. Further, since the flocculant dissolving machine 8 has the same structure as that of the first embodiment, the sectional view taken along the line AA in FIG. 2 and the sectional view taken along the line BB in FIG. The sludge dewatering system according to the third embodiment is different from the sludge dewatering system according to the first embodiment in the configuration for generating the first flocculant solution in the first flocculant supply step, Similarly, the point that the flocculant solution tank 6B, the flocculant dissolver 8B, the pressure pump 22B, the controller 23B, and the like are applied is greatly different. In addition, the configuration and operation of the sludge dewatering system is substantially the same as in the first embodiment. Moreover, the production | generation process of the 1st flocculant solution by a 1st flocculant supply process is the same as the production | generation process of a 2nd flocculant solution.

  As described above, according to the sludge dewatering system of the third embodiment, in addition to the various effects shown in the first embodiment, there are the following effects. The configuration in which a plurality of large-capacity flocculant dissolution tanks 4A and 4B are installed as in the first flocculant supply process of the first embodiment has a large installation area. On the other hand, in the first coagulant supply process of the third embodiment, since it is a main configuration of the small-capacity coagulant solution tank 6B and the coagulant dissolver 8B, the installation area is small and the sludge dewatering system is installed. There is a great effect where the area is limited. Moreover, even when the property of the sludge to be treated continues for a long time in an emergency state, and the amount of the first flocculant solution used is greatly reduced as compared with the normal case, the large capacity of the first embodiment is increased. In the configuration using the flocculant dissolution tanks 4A and 4B, there is a problem that the aggregation performance of the stored first flocculant solution is deteriorated. However, in the configuration of the first flocculant supply process of the third embodiment, the shortness is short. Since the first flocculant solution is generated in time and supplied to the treated sludge, there is an effect that the flocculant performance of the first flocculant solution does not deteriorate.

Embodiment 4 FIG.
FIG. 7 is a flowchart showing the sludge dewatering system in the fourth embodiment. The same parts as those in FIG. Further, since the flocculant dissolving machine 8 has the same structure as that of the first embodiment, the sectional view taken along the line AA in FIG. 2 and the sectional view taken along the line BB in FIG. The sludge dewatering system according to the fourth embodiment is different from the sludge dewatering system according to the first embodiment in that each of the first flocculant solution supply pipe 5 and the second flocculant solution supply pipe 9 is used as the sludge supply pipe 2. The point which connected individually and the point which connected the 2nd flocculant solution supply pipe 9 to the downstream rather than the connection location of the 1st flocculant solution supply pipe 5 of the sludge supply pipe 2 differ greatly.

  In the sludge dewatering system of Embodiment 4, the first flocculant solution and the second flocculant solution are individually supplied to the treated sludge without being mixed. In other words, normally, the first flocculant solution is supplied from the first flocculant solution supply step to the treated sludge, and the suspended sludge particles in the treated sludge are promoted to be dehydrated by the sludge dewatering machine 1. Process. If the sludge floc formation of the suspended solid particles is insufficient even when the properties of the sludge to be treated are suddenly changed and the first flocculant solution is supplied, the second flocculant is supplied in the second flocculant supply step. Produce solution and supplementally supply to treated sludge, promote further growth of sludge flocs with insufficient growth, and maintain dehydrated sludge moisture content and separation liquid properties within specified range after dehydration treatment It is supposed to be. Depending on the tendency of the property change of the treated sludge to be dewatered, normally, only the first flocculant solution is supplied to the treated sludge, and when the property of the treated sludge changes suddenly, the second Only the flocculant solution may be supplied. Other configurations and operations of the sludge dewatering system are substantially the same as those in the first embodiment.

  As described above, according to the sludge dewatering system of the fourth embodiment, various effects other than (5) and (6) shown in the first embodiment can be obtained, and the following effects are also obtained. There is. Even if the properties of the sludge to be treated change abruptly and the formation of sludge flocs is insufficient with only the first flocculant solution, the sludge flocs can only be added by supplying the second flocculant solution as an emergency. When the formation is sufficient, it is not necessary to control the mixing ratio of the mixed flocculant by the controller 23. Therefore, the control becomes simpler than the first embodiment, and the initial cost of the controller 23 and the like is reduced. Is effective.

Embodiment 5 FIG.
FIG. 8 is a flowchart showing the sludge dewatering system in the fifth embodiment. The same parts as those in FIG. Further, since the flocculant dissolving machine 8 has the same structure as that of the first embodiment, the sectional view taken along the line AA in FIG. 2 and the sectional view taken along the line BB in FIG. The sludge dewatering system according to the fifth embodiment is different from the sludge dewatering system according to the second embodiment in that the second flocculant is located upstream of the connection point of the first flocculant solution supply pipe 5 in the sludge supply pipe 2. The difference is that the solution supply pipe 9 is connected. In addition, the configuration and operation of the sludge dewatering system is substantially the same as in the fourth embodiment.

  As described above, according to the sludge dewatering system of the fifth embodiment, in addition to the various effects shown in the fourth embodiment, the flocculant applied as the first flocculant and the flocculant applied as the second flocculant. When it is more effective to promote the formation of sludge flocs by supplying the second flocculant to be additionally supplied in the event of emergency to the treated sludge before the first flocculant to be used at normal times due to factors such as differences in the characteristics of the agent Is particularly effective.

Embodiment 6 FIG.
FIG. 9 is a flowchart showing the sludge dewatering system in the sixth embodiment. The same parts as those in FIG. Further, since the flocculant dissolving machine 8 has the same structure as that of the first embodiment, the sectional view taken along the line AA in FIG. 2 and the sectional view taken along the line BB in FIG. The sludge dewatering system according to the sixth embodiment is different from the sludge dewatering system according to the fourth embodiment in the configuration for generating the first flocculant solution in the first flocculant supplying step, Similarly, the point that the flocculant solution tank 6B, the flocculant dissolver 8B, the pressure pump 22B, the controller 23B, and the like are applied is greatly different. In addition, the configuration and operation of the sludge dewatering system is substantially the same as in the fourth embodiment. Moreover, the production | generation process of the 1st flocculant solution by a 1st flocculant supply process is the same as the production | generation process of a 2nd flocculant solution.

  As described above, according to the sludge dewatering system of the sixth embodiment, in addition to the various effects shown in the fourth embodiment, the specific effects shown in the third embodiment can also be obtained.

Embodiment 7
FIG. 10 is a flowchart showing the sludge dewatering system in the seventh embodiment. The same parts as those in FIG. Further, since the flocculant dissolving machine 8 has the same structure as that of the first embodiment, the sectional view taken along the line AA in FIG. 2 and the sectional view taken along the line BB in FIG. The sludge dewatering system according to the seventh embodiment is configured to supply the sludge to be treated to a plurality of sludge dewaterers 1A, 1B, and 1C (three in FIG. 10) from one sludge supply pipe 2, and the second aggregation The point that the second flocculant solution flowing out from the flocculant dissolver 8 in the agent supply step can be temporarily stored in the flocculant solution supply tank 25 is largely different from that of the first embodiment.

  In the sludge dewatering system according to the seventh embodiment, the sludge supply pipe 2 has branch supply pipe portions 2A, 2B, 2C connected to the sludge dehydrators 1A, 1B, 1C. The sludge supply pumps 3A, 3B, and 3C are provided in the 2B and 2C, respectively. The branch supply pipes 2A, 2B, 2C are connected to branch supply pipes 5C, 5D, 5E on the downstream side of the first flocculant solution supply pipe 5, and the branch supply pipes 5C, 5D. , 5E are respectively provided with solution pumps 17A, 17B, 17C. Further, a flocculant solution supply tank 25 is disposed in the flocculant solution outflow system of the flocculant dissolver 8. In this flocculant solution tank 25, a second flocculant solution supply pipe 24 that causes the second flocculant solution flowing out from the flocculant solution outlet 80C of the flocculant dissolver 8 to flow into the flocculant solution supply tank 25, and A second flocculant solution supply pipe 26 that supplies the second flocculant solution flowing out from the flocculant solution supply tank 25 to the first flocculant solution of the first flocculant solution supply pipe 5 system is connected. The second flocculant solution supply pipe 26 has branch supply pipe portions 26A, 26B, and 26C connected to the branch supply pipe portions 5C, 5D, and 5E of the first flocculant solution supply pipe 5, respectively. Then, solution pumps 27A, 27B, and 27C are provided in the branch supply pipe portions 26A, 26B, and 26C of the second flocculant solution supply pipe 26, respectively.

  Next, the operation of the sludge dewatering system in the seventh embodiment will be described. In the sludge dewatering process, the sludge to be treated flowing through the sludge supply pipe 2 is supplied from the branch supply pipe portions 2A, 2B, 2C of the sludge supply pipe 2 with a plurality of sludge supply pumps 3A, 3B, 3C. 1A, 1B and 1C are distributed and supplied. At the same time, in the first flocculant supply step, the first flocculant solution flowing into the first flocculant solution supply pipe 5 from either one of the flocculant solution tanks 4A and 4B is supplied to the first flocculant solution. The branched supply pipe parts 5C, 5D, 5E of the pipe 5 are supplied to the branched supply pipe parts 2A, 2B, 2C of the sludge supply pipe 2 by the solution pressure feed pumps 17A, 17B, 17C of the respective systems. As a result, the treated sludge injected with the first flocculant solution is distributed and supplied to each of the sludge dewatering machines 1A, 1B, and 1C, so that the sludge floc formation of the suspended particles in the treated sludge is promoted and the sludge is promoted. In the dehydrators 1A, 1B, and 1C, the sludge to be treated can be efficiently separated into the separation liquid and the dewatered sludge, and the moisture content of the dewatered sludge after the dewatering and the properties of the separation liquid can be maintained within a predetermined range. it can.

  The above is the sludge dewatering process at the normal time, and the second flocculant supply step is executed in an emergency when the properties of the treated sludge change rapidly. In the second flocculant supply step, the second flocculant solution generated in the flocculant solution tank 6 flows into the flocculant dissolver 8 and is dissolved as in the case of the first embodiment. After the dissolution treatment, the second flocculant solution is transferred from the flocculant dissolver 8 to the second flocculant solution supply pipe 24 to be transferred to the flocculant solution supply tank 25 and temporarily stored. The second flocculant solution stored in the flocculant solution supply tank 25 is branched and supplied to the flocculant solution supply pipe 26 by the activation of the solution pumps 27A, 27B and 27C of the second flocculant solution supply pipe 26 system. The pipe parts 26A, 26B, and 26C are distributed and supplied to the branch supply pipe parts 5C, 5D, and 5E of the first flocculant solution supply pipe 5, respectively.

  In this way, in the branch supply pipe portions 5C, 5D, and 5E of the first flocculant solution supply pipe 5, the first flocculant solution and the second flocculant solution are mixed. As in the case of the first embodiment, Mixed flocculant solutions with various properties can be produced. After the mixed flocculant solution is supplied to the to-be-treated sludge diverted to the branch supply pipe portions 2A, 2B and 2C of the sludge supply pipe 2, the to-be-treated sludge is distributed and supplied to each of the sludge dehydrators 1A, 1B and 1C. Is done. As a result, even when the properties of the treated sludge change rapidly, the plurality of sludge dewatering machines 1A, 1B, 1C can efficiently separate the treated sludge into the separation liquid and the dewatered sludge, and the dewatering. The water content of the later dewatered sludge and the properties of the separated liquid can be maintained within a predetermined range. In addition, the configuration and operation of the sludge dewatering system is substantially the same as in the first embodiment.

  As described above, according to the sludge dewatering system in the seventh embodiment, in addition to the same effects as those in the first embodiment, there are the following effects. In the second flocculant supply step in the first embodiment, since the second flocculant solution is supplied to one first flocculant solution supply pipe 5, the flocculant dissolver 8 is provided from the flocculant solution tank 6. In addition, it was possible to directly supply the second flocculant solution to the first flocculant solution supply pipe 5 using the pumping force of the pump 22 that pumps the second flocculant solution. On the other hand, in the case of the seventh embodiment, in the second flocculant supply step, the second flocculant solution is supplied to the branch supply pipe portions 5C, 5D, 5E of the first flocculant supply pipe 5 at a plurality of locations. Although it is necessary to supply, a branch pipe part is provided in the second flocculant solution supply pipe 24 from the flocculant dissolver 8 to the branch supply pipe parts 5C, 5D, and 5E to try to supply directly by the pumping force of the pump 22. However, it is difficult to equalize the pipe resistance of each branch pipe part, and there is a problem that the supply amount of the second flocculant solution to each branch pipe part varies.

  By adopting the configuration of the sludge dewatering system of the seventh embodiment, the second flocculant solution dissolved by the flocculant dissolver 8 is temporarily stored in the flocculant solution supply tank 25, and each branch supply pipe section 26A, 26B is stored. , 26C, the second coagulant solution is supplied to the branch pipe portions 5C, 5D, 5E of the first coagulant solution supply pipe 5 by the solution pressure pumps 27A, 27B, 27C. The required amount can be supplied without variation. In addition, since the second flocculant solution that has been dissolved can be temporarily stored in the flocculant solution supply tank 25, the control of the flocculant dissolver 8 becomes temporarily unstable due to some trouble, Even when there is a variation in the dissolution concentration, etc., since a predetermined amount of the second flocculant solution is mixed when temporarily stored in the flocculant solution supply tank 25, the variation in the dissolution concentration, etc. There is also an effect that can be made uniform.

  As in the case of the second embodiment, the sludge dewatering system includes the branch supply pipe portions 26A, 26B, and 26C of the second flocculant solution supply pipe as branch supply pipe portions 2A, 2B, and 2C of the sludge supply pipe 2, respectively. The branch tube portions 5C, 5D, 5E of the first flocculant solution supply pipe 5 may be connected to the branch supply pipe portions 26A, 26B, 26C of the second flocculant solution supply pipe, respectively. In this case, in addition to the effects shown in the second embodiment, the effects unique to the seventh embodiment can be obtained. Further, when the flocculant solution tank 6B, the flocculant dissolver 8B, the pumping pump 22B, the controller 23B, and the like are applied to the first flocculant supply step shown in the third embodiment, the effects unique to the third embodiment are also obtained. can get.

Embodiment 8 FIG.
FIG. 11 is a flowchart showing the sludge dewatering system in the eighth embodiment. The same parts as those in FIG. Further, since the flocculant dissolving machine 8 has the same structure as that of the first embodiment, the sectional view taken along the line AA in FIG. 2 and the sectional view taken along the line BB in FIG. In the seventh embodiment, the first flocculant solution supply pipe 5 is connected to the sludge supply pipe 2, and the second flocculant solution supply pipe 26 is connected to the first flocculant solution supply pipe 5. The second flocculant solution is supplied from the second flocculant solution supply pipe 26 to the first flocculant solution flowing through the first flocculant solution supply pipe 5, and the first flocculant solution and the second flocculant solution are mixed. The flocculant solution is supplied from the first flocculant solution supply pipe 5 to the sludge to be treated in the sludge supply pipe 2. In the sludge dewatering system according to the eighth embodiment, as in the case of the fourth embodiment. The point that the first flocculant solution supply pipe 5 and the second flocculant solution supply pipe 26 are individually connected to the sludge supply pipe 2 is greatly different from the seventh embodiment.

  That is, the sludge dewatering system according to the eighth embodiment is the same as the sludge dewatering system of the seventh embodiment except that the branch supply pipe portions 26A, 26B, and 26C of the second flocculant solution supply pipe 26 are replaced with the first flocculant. The branch supply pipe portions 5C, 5D, and 5E of the solution supply pipe 5 are connected on the downstream side of the position where they are connected to the branch supply pipe portions 2A, 2B, and 2C of the sludge supply pipe 2. Thus, in addition to the effects shown in the fourth embodiment, the configuration characteristic of the effect of the seventh embodiment can be obtained. As in the case of the fifth embodiment, the branch supply pipe portions 26A, 26B, and 26C of the second flocculant solution supply pipe 26 are connected to the branch supply pipe portions 5C, 5D, and 5C of the first flocculant solution supply pipe 5. It is also possible to adopt a configuration in which 5E is connected upstream of the position where the sludge supply pipe 2 is connected to the branch supply pipe portions 2A, 2B, 2C. In this case, the configuration shown in Embodiment 5 is used. In addition to the effects, effects unique to the configuration of the seventh embodiment can also be obtained.

  Note that the configuration and operation of other sludge dewatering systems are substantially the same as those in the fourth embodiment. Further, when the flocculant solution tank 6B, the flocculant dissolving machine 8B, the pumping pump 22B, the controller 23B, and the like are applied to the first flocculant supply step shown in the sixth embodiment, the effects unique to the sixth embodiment are simultaneously obtained. can get.

Embodiment 9 FIG.
FIG. 12 is a flowchart showing the sludge dewatering system in the ninth embodiment. The same parts as those in FIG. Further, since the flocculant dissolving machine 8 has the same structure as that of the first embodiment, the sectional view taken along the line AA in FIG. 2 and the sectional view taken along the line BB in FIG. In the sludge dewatering system of the seventh embodiment, a plurality of sludge dewaterers 1A, 1B, and 1C are formed of the same type. On the other hand, in the sludge dewatering system of the ninth embodiment, a plurality of sludge dewaterers are configured in different types, and among the multiple types of sludge dewaterers, the sludge dewaterer with poor dewatering performance is used. The difference is that the second flocculant solution is supplied only to one flocculant solution supply pipe.

  In the seventh embodiment, the centrifugal dehydrator is applied to each of the sludge dewaterers 1A, 1B, and 1C. In the sludge dewatering system of the ninth embodiment, instead of the sludge dewaterer 1C, a belt press having poor dewatering performance. The dehydrator is applied as the sludge dehydrator 1D. Further, only the flocculant solution outlet 80 </ b> C of the flocculant dissolver 8 and the downstream branch pipe portion 5 </ b> E of the first flocculant solution supply pipe 5 are connected by the second flocculant solution supply pipe 9. As a result, the second flocculant solution is merged with the first flocculant solution from the second flocculant solution supply pipe 9 only by the branch supply pipe portion 5E of the first flocculant solution supply pipe 5, thereby The mixed flocculant solution of the solution and the second flocculant solution is supplied only from the branch supply pipe portion 2C of the sludge supply pipe 2 to the sludge dehydrator (belt press dehydrator) 1D, and the other sludge dehydrators 1A and 1B are supplied with the first Only one flocculant solution is supplied.

  The sludge dewatering system according to the ninth embodiment has the following effects. When adding a sludge dewatering machine to an existing sludge dewatering system, or when replacing a sludge dewatering system with multiple sludge dewatering machines due to deterioration, etc. And the newly installed sludge dewatering machine, there is a difference in the degree of sludge floc formation in the treated sludge necessary to keep the moisture content of the dewatered sludge and the properties of the separated liquid within the specified range. appear. For example, if the belt press dewatering machine (sludge dewatering machine 1D) does not form a larger sludge floc in the treated sludge than the centrifugal dewatering machines (sludge dewatering machines 1A and 1B), the water content of the dewatered sludge after dewatering It is difficult to keep the ratio and the properties of the separation liquid within the predetermined ranges. However, select the type of flocculant suitable for the belt press dewatering machine (sludge dewatering machine 1D) or increase the supply amount of the flocculant solution and supply it to all the sludge dewatering machines 1A, 1B, 1D. Is not preferable because of increased running cost.

  The sludge dewatering system according to the ninth embodiment is the first flocculant solution only for the sludge to be treated supplied to the sludge dewatering machine (belt press dewatering machine) 1D that needs to particularly promote the formation of the sludge floc of the treated sludge. Water content of dewatered sludge after dewatering in all sludge dewatering machines 1A, 1B, 1D by supplying a mixed flocculant solution produced by mixing the second flocculant solution and the second flocculant solution to promote further formation of sludge flocs The properties of the separation liquid can be within a predetermined range. Further, when the performance difference between the sludge dehydrators 1A, 1B, and 1D is small, it is a time to dehydrate the treated sludge having the normal properties, and one kind of flocculant solution is added from the first flocculant supply step. When all the sludge dewatering machines can keep the water content of the dewatered sludge and the properties of the separated liquid within the predetermined range simply by supplying them to the treated sludge, the sludge dewatering machine 1D with poor performance can be used as well. Only one flocculant solution is supplied. When the properties of the sludge to be treated change drastically and the sludge dewatering machine 1D cannot dehydrate the dewatered sludge and separation liquid within a predetermined range, the second flocculant solution is supplied to the first flocculant solution. By producing a mixed flocculant solution with enhanced coagulation performance and supplying the mixed flocculant solution only to the treated sludge supplied to the sludge dewatering machine 1D, the sludge dewatering machine 1D also has a water content within a predetermined range. It is advisable to maintain dehydrated sludge and a separated liquid having a property within a predetermined range. The configuration and operation of the other sludge dewatering system are substantially the same as those in the first embodiment.

  As described above, according to the sludge dewatering system of the ninth embodiment, in addition to the various effects shown in the first embodiment, the sludge dewatering machine (belt press) that needs to particularly promote the formation of the sludge floc of the treated sludge. Dehydrator) By supplying the mixed flocculant solution produced by mixing the first flocculant solution and the second flocculant solution only to the treated sludge supplied to 1D, and promoting the further formation of sludge floc, The water content of the dewatered sludge after dewatering in the sludge dewatering machines 1A, 1B, and 1D and the properties of the separated liquid can be within the predetermined ranges. As in the case of the second embodiment, the second flocculant solution supply pipe 9 is connected to the branch supply pipe portion 2C of the sludge supply pipe 2 and the first flocculant solution supply pipe 5 is branched. The pipe portion 5E may be connected to the second flocculant solution supply pipe 9, and in this case, in addition to the effects shown in the second embodiment, the effects unique to the ninth embodiment can be obtained. Further, when the flocculant solution tank 6B, the flocculant dissolver 8B, the pumping pump 22B, the controller 23B, and the like are applied to the first flocculant supply step shown in the third embodiment, the effects unique to the third embodiment are also obtained. can get.

Embodiment 10 FIG.
FIG. 13 is a flowchart showing the sludge dewatering system in the tenth embodiment. The same parts as those in FIG. Further, since the flocculant dissolving machine 8 has the same structure as that of the first embodiment, the sectional view taken along the line AA in FIG. 2 and the sectional view taken along the line BB in FIG. In the sludge dewatering system of the ninth embodiment, the second flocculant solution supply pipe 9 is connected to the branch supply pipe section 5E of the first flocculant solution supply pipe 5, and the first branch supply pipe section 5E is used for the first. The flocculant solution and the second flocculant solution are merged and supplied to the branch supply pipe portion 2C of the sludge supply pipe 2. In the sludge dewatering system of the tenth embodiment, as in the case of the fourth embodiment, the first The second flocculant solution supply pipe 9 is connected downstream of the position where the branch supply pipe portion 5E of the first flocculant solution supply pipe 5 is connected to the branch supply pipe portion 2C of the sludge supply pipe 2. This is greatly different from the ninth embodiment. Other configurations and operations of the sludge dewatering system are substantially the same as those in the fourth embodiment.

  As described above, according to the sludge dewatering system in the tenth embodiment, in addition to the effects shown in the fourth embodiment, effects unique to the configuration of the ninth embodiment can also be obtained. As in the case of the fifth embodiment, the second flocculant solution supply pipe 9 is connected to the branch supply pipe portion 5C of the sludge supply pipe 2 through the branch supply pipe portion 5E of the first flocculant solution supply pipe 5. In this case, in addition to the effect shown in the fifth embodiment, an effect peculiar to the configuration in the ninth embodiment can be obtained. It is done. Further, when the flocculant solution tank 6B, the flocculant dissolving machine 8B, the pumping pump 22B, the controller 23B, and the like are applied to the first flocculant supply step shown in the sixth embodiment, the effects unique to the sixth embodiment are simultaneously obtained. can get.

Embodiment 11 FIG.
FIG. 14 is a flowchart showing the sludge dewatering system according to the eleventh embodiment. The same parts as those in FIG. Further, since the flocculant dissolving machine 8 has the same structure as that of the first embodiment, the sectional view taken along the line AA in FIG. 2 and the sectional view taken along the line BB in FIG. The sludge dewatering system according to the ninth embodiment measures the viscosity of the second flocculant solution flowing out from the flocculant dissolver 8 in the second flocculant supply step of the sludge dewatering system according to the first embodiment, and The point that the operation of the flocculant dissolver 8 is controlled in accordance with the measured viscosity value is greatly different from that of the first embodiment.

In the sludge dewatering system according to the eleventh embodiment, the second coagulant solution supply pipe 9 connecting the coagulant solution outlet 80C of the coagulant dissolver 8 and the first coagulant solution supply pipe 5 has an agglomeration. A viscometer 30 is provided for measuring the concentration of the second flocculant solution flowing out from the agent dissolver 8 and transmitting the measured value signal to the controller 23. The viscometer 30 includes a rotary type, a vibration type, a thin tube type, and a falling body type, any of which can be applied, and the general structure of each type will be described below.
(1) The rotary viscometer 30 measures the rotational torque by inserting a rotating cylindrical tube that is rotated by the power of the driving machine into the coagulant solution to be measured, and calculates the viscosity from the correlation with the rotational torque. It has a structure.
(2) The vibration type viscometer 30 has a structure in which a vibrator is inserted into a coagulant solution to be measured, and the viscosity is calculated from the correlation with the amplitude and the amount of current required to maintain vibration.
(3) The thin-tube viscometer 30 has a structure in which a flocculant solution to be measured is passed through a thin tube, the differential pressure before and after that is measured, and the viscosity is calculated from the correlation with the differential pressure.
(4) The falling-body viscometer 30 drops a cylinder in a coagulant solution to be measured in a vertically placed circular tube, measures the drop time, and calculates the viscosity from the correlation with the drop time. It has a structure to do.

  The controller 23 controls the operation of the flocculant dissolver 8, that is, the rotational speed of the driving device 88 in accordance with the viscosity measurement value of the flocculant solution by the viscometer 30. For each type of the second coagulant supplied from the coagulant supply machine 18 in the second coagulant supply process to the coagulant solution tank 6, the viscosity and coagulation performance of the second coagulant solution (the coagulation performance is actually The amount of water content of the dewatered sludge and the properties of the separated liquid when the sludge is supplied to the treated sludge and dehydrated with the sludge dehydrator 1 are examined in advance, and the optimum The viscosity at the time of dissolution is determined as an optimum value, and the viscosity of the optimum value (hereinafter referred to as the optimum viscosity value) is stored in the controller 23. Thus, the measurement value signal is transmitted from the viscometer 30 constantly or every predetermined time to the controller 23 storing the viscosity optimum value.

  For example, the following control can be applied to the operation control when the coagulant dissolving machine 8 performs the dissolution treatment as a simple method. First, the driving device 88 is started at a low speed, the pressing member 86 is moved on the inner surface of the cylindrical screen 85 at a low speed, and the dissolution process of undissolved particles is started. The rotational speed of the driving device 88 is gradually increased until the viscosity measurement value of the second flocculant solution that has been measured by the viscometer 30 and taken into the controller 23 by the measurement value signal becomes the optimum viscosity value. To go. When the measured viscosity value reaches the optimum viscosity value, the rotational speed of the driving device 88 is maintained. Usually, if the property of the sludge to be treated does not change significantly, the supply amount of the second flocculant solution is not changed so much, and this simple control alone can sufficiently cope with it. Moreover, when the property of the to-be-treated sludge changes abruptly and it becomes necessary to increase the supply amount of the second flocculant solution to the to-be-treated sludge, the flocculant solution dissolved by the flocculant dissolver 8 Since the flow rate increases and the amount of undissolved particles adhering to the inner surface of the cylindrical screen 85 also increases, naturally the optimum rotational speed of the driving device 88 changes. In this case, the operation manager of the sludge dewatering system may restart the controller 23 and readjust so that the same control is performed again to achieve the optimum rotation speed of the drive unit 88.

  In the normal case, the supply amount of the second flocculant solution to the treated sludge is determined by checking the state of dewatered sludge discharged from the sludge dehydrator 1 and the state of the separated liquid by the operation manager of the sewage dewatering system. Since the increase / decrease is determined, it is less necessary for the controller 23 to automatically perform control for readjusting the rotational speed of the driving device 88 in accordance with the increase / decrease in the supply amount of the second flocculant solution. However, when the controller 23 automatically controls the supply amount of the second flocculant solution according to the properties of the sludge to be treated, the second change is made so that the controller 23 can recognize the change in the supply amount. It is preferable to control the rotational speed of the driving device 88 by installing a flow meter in the second coagulant solution supply pipe 9 or the like, or incorporating a circuit for recognizing the rotational speed of the pressure pump 22 into the controller 23. In particular, when the supply amount of the second flocculant solution automatically varies, it is difficult to control the driving device 88 only with the actual measurement data of the current viscosity measurement value. Viscosity measurement values from the previous time or several times before can be stored in the controller 23, and a control for controlling the rotational speed of the driving device 88 by incorporating a change in the viscosity of the second flocculant solution is incorporated. It is also desirable to incorporate advanced controls such as adaptive control, fuzzy control, and neural network control.

  Next, the operation of the sludge dewatering system in the eleventh embodiment will be described. As in the first embodiment, the first flocculant step is executed, and both the first flocculant supply step and the second flocculant supply step are executed in an emergency such as a sudden change in the properties of the sludge to be treated. Is done. In the second flocculant supply step, the second flocculant solution flowing out from the flocculant dissolver 8 is supplied to the first flocculant solution supply pipe 5 through the flocculant solution supply pipe 9. the viscosity of 2 flocculant solution is measured by the viscosity meter 30, the measured value signal is transmitted to the controller 23. As described above, the controller 23 controls the rotational speed of the driving device 88 in accordance with the measured viscosity value of the second flocculant solution. By the rotation speed control, the second flocculant solution having the optimum viscosity is supplied to the first flocculant solution flowing through the first flocculant solution supply pipe 5. Thus, in the first flocculant solution supply pipe 5, the first flocculant solution flowing through the first flocculant solution and the second flocculant solution having the optimum viscosity supplied from the flocculant solution supply pipe 9 are mixed, and the mixed flocculant. The solution is supplied from the first flocculant solution supply pipe 5 to the sludge to be treated in the sludge supply pipe 2.

  And the to-be-processed sludge supplied with the said mixed flocculant solution is sent to the sludge dehydrator 1 by the sludge supply pipe 2, and in this sludge dehydrator 1, sludge flocs of the sludge flocs are produced by the strong coagulation action of the mixed flocculant solution. The treated sludge whose formation has been promoted is efficiently separated into the dewatered sludge and the separation liquid, and the dewatering rate of the dewatered sludge after dewatering and the properties of the separation liquid are maintained within a predetermined range. Other configurations and operations of the sludge dewatering system are substantially the same as those in the first embodiment.

As described above, according to the sludge dewatering system of the eleventh embodiment, the second flocculant such as particles is dissolved in the dissolved water to generate the second flocculant solution. The flocculant and dissolved water are stirred and mixed by the stirrer 21 to produce a second flocculant solution. Further, the flocculant dissolver 8 introduces the second flocculant solution into the cylindrical screen 85 and screen-filters it. A configuration in which the operation of the flocculant dissolver 8 is controlled by the controller 23 based on the result of measuring the viscosity of the second flocculant solution flowing out of the flocculant dissolver 8 with the viscometer 30 after performing the dissolution treatment of the dissolved particles. Therefore, in addition to the effects shown in the first embodiment, the following effects can be obtained.
(1) The flocculant solution has a property that the agglomeration performance changes depending on the dissolution condition in the dissolved water, and the correlation between the dissolution condition and the aggregation performance varies depending on the type of the aggregating agent to be used. Further, the degree of dissolution of the flocculant solution has a correlation with the viscosity. That is, there is a correlation between the viscosity of the flocculant solution and the aggregation performance. From this correlation, the viscosity at which the second flocculant solution exhibits the optimum flocculating performance is specified as an optimum value and stored in the controller 23 in advance, and the flocculant dissolver 8 is determined according to the measured value of the viscometer 30. By always controlling the operation of the second flocculant, the second flocculant solution having the optimum flocculant performance is supplied to the first flocculant solution, and the mixed flocculant solution is supplied to the treated sludge in the sludge supply pipe 2. This makes it possible to significantly improve the dewatering performance.
(2) The viscosity is measured as an indicator of the dissolution condition of the second flocculant solution, and the operation of the flocculant dissolver 8 is adjusted by the controller 23 according to the measured value. Since the two coagulant solutions can be supplied to the first coagulant solution and the mixed coagulant solution can be supplied to the treated sludge, there is an effect that high dewatering performance can be maintained even when the properties of the treated sludge change.
(3) Even when the supply amount of the second flocculant solution is increased or decreased, the controller 23 adjusts the operation of the flocculant dissolver 8 according to the measured value of the viscometer 30 of the second flocculant solution. Even if the amount of the second flocculant solution flowing into the flocculant dissolver 8 changes, there is an effect that the second flocculant solution having the optimum flocculant performance can be supplied.
(4) In the case of manually adjusting a conventional flocculant dissolver, it is difficult for even a skilled worker to adjust so as to obtain an optimal dissolution condition, and the rotational speed is slightly lower than the optimal value. When adjusted, there is a concern about insufficient dissolution of the second flocculant, and therefore, the number of rotations is usually adjusted to be slightly higher than the optimum value, and it seems to be over-stirred. Moreover, even if it is the 2nd flocculant solution produced | generated by the state of an overstirring state and the aggregation performance slightly fell, in order to exhibit high aggregation performance, more 2nd flocculant solutions are supplied. In the sludge dewatering system according to the eleventh embodiment, it is possible to prevent the flocculant dissolver 8 from being over-stirred, so that it is not necessary to supply more than a predetermined amount of the flocculant solution, and the running cost is reduced. There is an effect that can.
(5) Since the operation of the flocculant dissolver 8 can be maintained in an optimum state by the viscometer 30 and the controller 23, it is safe to adjust the operation of the flocculant dissolver 8 manually. As compared with the case where the adjustment has been made to be more excessive than the optimum state, the power consumption can be reduced and the wear of the parts can also be reduced.
(6) The second flocculant solution produced by stirring and mixing the second flocculant and the dissolved water in the flocculant solution tank 6 is introduced into the cylindrical container 80 of the flocculant dissolver 8 and is introduced into the cylindrical screen 85. The second flocculant solution in which the undissolved particles remain is obtained by filtering the undissolved particles of the second flocculant adhering to the inner surface of the cylindrical screen 85 by pressing the pressing member 86. There is an effect that it can be prevented from being supplied to the first flocculant solution, and undissolved particles can be reliably dissolved.
(7) The controller 23 is configured to control the rotation of the drive unit 88 of the flocculant dissolver 8 according to the viscosity measurement value of the second coagulant solution measured by the viscometer 30. The speed at which 88 moves along the inner surface of the cylindrical screen 85 of the pressing member 86 to which the moving force is applied via the holding members 87A and 87B can be adjusted, and a melting process with excellent responsiveness can be performed. effective.

  Even in the case where the flocculant dissolver 8B is applied to the first flocculant supply process as shown in the third embodiment, the configuration of the viscometer 30 and the controller 23 is used to drive the flocculant dissolver 8B. By controlling the rotation, the same effect as in the eleventh embodiment can be obtained.

Embodiment 12 FIG.
FIG. 15 is a flowchart showing the sludge dewatering system in the twelfth embodiment. The same parts as those in FIG. Further, since the flocculant dissolving machine 8 has the same structure as that of the first embodiment, the sectional view taken along the line AA in FIG. 2 and the sectional view taken along the line BB in FIG. In the sludge dewatering system according to the twelfth embodiment, the first flocculant solution supply pipe 5 and the second flocculant solution supply pipe 9 are individually connected to the sludge supply pipe 2 as in the fourth embodiment. And the point which connected the 2nd flocculant solution supply pipe | tube 9 to the downstream rather than the connection location of the 1st flocculant solution supply pipe | tube 5 of the sludge supply pipe | tube 2 differs greatly from the said Embodiment 11. FIG. Other structures are the same as those of the eleventh embodiment.

  As described above, according to the sludge dewatering system of the twelfth embodiment, in addition to the effects shown in the third embodiment, effects unique to the configuration of the eleventh embodiment can be obtained. As in the case of the fifth embodiment, the second flocculant solution supply pipe 9 is connected upstream of the position where the first flocculant solution supply pipe 5 is connected to the sludge supply pipe 2. In this case, in addition to the effects shown in the fifth embodiment, effects unique to the configuration of the eleventh embodiment can be obtained. Further, even when the flocculant dissolver 8B is applied to the first flocculant supply step as shown in the sixth embodiment, the configuration of the viscometer 30 and the controller 23 is used to drive the flocculant dissolver 8B. By controlling the rotation, the same effect as in the twelfth embodiment can be obtained.

The results when the sludge is actually dehydrated using the configuration of the sludge dewatering system shown in the first embodiment will be described below. This Example 1 was performed on the following implementation conditions.
[Conditions for implementation]
○ 1st flocculant supply process ・ Flocculant solution tank 4A, 4B Capacity: 60m ³ each
・ Agitator 14A, 14B: 15.0kW
・ Dissolved water: treated water in sewage treatment facilities ・ First flocculant: cationic polymer flocculant Main ingredient: Dimethylaminoethyl acrylate
First flocculant solution: 0.3% solution concentration
-Solution pump 17: Single screw pump Discharge flow rate up to 330L / min,
Power 7.5kW
○ Second flocculant supply process ・ Flocculant solution tank 6 Capacity: 1.4 m ³
・ Agitator 21: 2.2 kW
・ Dissolved water: treated water at sewage treatment facility, supply amount 183L / min
・ Second flocculant: Cationic polymer flocculant (main component: amidine), maximum supply amount 360 g / min
Second flocculant solution: solution concentration 0.2%
・ Pressure pump 22: Single screw pump Discharge flow rate up to 180L / min,
Power 3.7kW
・ Flocculant dissolver 8: Driver 88 Uses an electric motor and controls the number of revolutions with an inverter
(Control frequency range 17-42Hz)
○ Sludge dewatering process ・ Sludge dewatering machine 1: Centrifugal dewatering machine Setting differential speed 5min ^-1
・ Supply of sludge to sludge dewatering machine 1: 80m ³ / h
・ Total amount of sludge supplied to sludge dewatering machine 1: 2000m ³
・ Powder amount of mixed flocculant solution: 180 L / min
・ Pouring rate of mixed flocculant solution: 1.0% / TS

  In Example 1, a relatively inexpensive granular cationic polymer flocculant having a wide application range is used as the first flocculant, and an expensive cationic polymer flocculant having a high aggregation effect but being expensive as the second flocculant (mainly Ingredient: Amidine) was used. Moreover, the supply amount (chemical injection amount) of the mixed flocculant solution obtained by mixing the first flocculant solution and the second flocculant solution to the treated sludge was 180 L / min. Then, five types of mixed flocculant solutions having a ratio of the second flocculant solution of 0%, 30%, 50%, 70%, and 100% are generated and supplied to the treated sludge, respectively. Dehydration treatment was performed. These results are shown in FIG.

  According to this, the water content of the dewatered sludge dehydrated by the sludge dewatering machine 1 is 77.5% when the mixing ratio of the second flocculant solution is 0%, whereas when the mixing ratio is 100%. It is 76.1%, and the water content of the dewatered sludge tends to decrease as the mixing ratio of the second flocculant solution is increased. Also, the sludge disposal cost is reduced to 2,515,000 yen when the mixing ratio is 100%, while it is 2,667 thousand yen when the mixing ratio is 0%. However, in order to increase the mixing ratio of expensive PVA, the total amount of drug costs is 180 thousand yen when the mixing ratio is 0%, but increases to 300 thousand yen when the mixing ratio is 100%. . Therefore, it is necessary to find an optimum mixing ratio with the total cost of the sludge disposal cost and the chemical cost of the dewatered sludge. Then, in the case of Example 1, when the mixing ratio of the second flocculant solution is 50%, the total cost is the lowest at 2,799 thousand yen, and only the first flocculant solution is supplied to the treated sludge ( That is, it has been found that a significant cost reduction of 848 thousand yen can be achieved compared to the case where the dehydration treatment is performed with the second flocculant solution mixing ratio of 0%. From the above results, it can be said that the running cost can be greatly reduced by applying the sludge dewatering system of the present invention and finding the optimum mixing ratio of the second flocculant solution.

It is a flowchart which shows the sludge dehydration system in Embodiment 1 of this invention. It is an AA line sectional view of the flocculant dissolver in Embodiment 1 of the present invention. It is a BB sectional view of the flocculent dissolver in Embodiment 1 of the present invention. It is a time chart figure of the to-be-processed sludge of the sludge dehydration system in Embodiment 1 of this invention. It is a flowchart which shows the sludge dehydration system in Embodiment 2 of this invention. It is a flowchart which shows the sludge dehydration system in Embodiment 3 of this invention. It is a flowchart which shows the sludge dehydration system in Embodiment 4 of this invention. It is a flowchart which shows the sludge dehydration system in Embodiment 5 of this invention. It is a flowchart which shows the sludge dehydration system in Embodiment 6 of this invention. It is a flowchart which shows the sludge dehydration system in Embodiment 7 of this invention. It is a flowchart which shows the sludge dehydration system in Embodiment 8 of this invention. It is a flowchart which shows the sludge dehydration system in Embodiment 9 of this invention. It is a flowchart which shows the sludge dehydration system in Embodiment 10 of this invention. It is a flowchart which shows the sludge dehydration system in Embodiment 11 of this invention. It is a flowchart which shows the sludge dehydration system in Embodiment 12 of this invention. It is a correlation diagram which shows the change of the moisture content of a dewatering sludge, a dewatering sludge disposal cost, and a chemical | medical agent expense when the mixing ratio of the 2nd flocculant solution in Example 1 is changed.

Explanation of symbols

1, 1A, 1B, 1C, 1D Sludge dewatering machine 2 Sludge supply pipe 2A, 2B, 2C Branch supply pipe section 3, 3A, 3B, 3C Sludge supply pump 4A, 4B Coagulant solution tank 5 Coagulant solution supply pipe 5A, 5B Branch pipe part 5C, 5D, 5E Branch supply pipe part 6, 6B Coagulant solution tank 7 Coagulant solution transfer pipe 8, 8B Coagulant dissolver 9 Coagulant solution supply pipe 10A, 10B Coagulant supplier 12A, 12B Dissolve Water supply pipes 13A, 13B Control valves 14A, 14B Agitators 15, 16 Open / close control valves 17, 17A, 17B, 17C Solution pumps 18, 18B Coagulant supply machines 19, 19B Dissolved water supply pipes 20, 20B Control valves 21, 21B Stirrer 22, 22B Pressure pump 23, 23B Controller 24 Coagulant solution supply pipe 25 Coagulant solution supply tank 26 Coagulant solution supply pipe 26A, 26B, 26C Branch supply Pipe parts 27A, 27B, 27C Solution pump 30 Viscometer 80 Cylindrical container 80A, 80B Flange part 80C Coagulant solution outlet 81A, 81B Flange lid 81C Coagulant solution inlet 82A, 82B Bolt / nut 83A, 83B Partition member 84A Primary chamber 84B Secondary chamber 85 Cylindrical screen 86 Press member 87A, 87B Holding member 88 Drive device 88A Drive shaft 88B Reducer 89 Bearing 101A, 101B Hopper-like container 102A, 102B Coagulant supply port 103A, 103B Supply port switch 180 Hopper-shaped container 181 Coagulant inlet 182 Supply port switch

Claims (3)

A sludge dewatering step including a sludge dewatering machine that separates the treated sludge into a separated liquid and a dewatered sludge, and a sludge supply pipe that supplies the treated sludge to the sludge dewatering machine;
A first flocculant supply step of supplying a flocculant solution generated from the flocculant and dissolved water to the treated sludge through a flocculant solution supply pipe;
A flocculant solution tank that generates a flocculant solution by stirring and mixing a flocculant different from the flocculant in the first flocculant supply step ;
A cylindrical container, a cylindrical screen disposed in the cylindrical container, one or more pressing members disposed in the cylindrical screen, a holding member for holding the pressing member, A drive unit that moves the pressing member along the inner surface of the cylindrical screen via a holding member, screens the flocculant solution introduced from the flocculant solution tank, and removes the flocculant in the flocculant solution. said flocculant solution discharged from the dissolving flocculant dissolver and coagulant dissolver Ri Do and a second coagulant supply process with the coagulant solution supply pipe for supplying the treated sludge,
Sludge dewatering system characterized that you supply a flocculant solution in both the first coagulant supply step or first coagulant supply step and the second coagulant supply process to be treated sludge. The flocculant solution supply pipe in the first flocculant supply step and the flocculant solution supply pipe in the second flocculant supply step are:
The sludge dewatering system according to claim 1, wherein the sludge dewatering system is joined and connected. A viscometer that measures the viscosity of the flocculant solution that has flowed out of the flocculant dissolver;
3. The sludge dewatering system according to claim 1, further comprising a controller that controls rotation of the driving device that is started and raised at a low speed in accordance with a measured value of the viscometer.

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