JP2010247111A - Sludge drying system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sludge drying system performing the drying of sludge while reducing environmental load as much as possible in treating the sludge and discharge water produced in wastewater purification facilities. <P>SOLUTION: The wastewater purification facilities are constituted so as to separate wastewater into sludge and discharge water purified to an outwardly dischargeable degree to perform the purification of the wastewater and includes a steam producing part producing steam by utilizing an internally circulating cooling medium of itself by performing direct or indirect heat exchange using the discharge water before discharged to the outside or the intermediate treated water in the wastewater purification facilities as a heat source and a drying part receiving the supply of the steam produced in the steam producing part and drying the sludge by the supplied steam to form dried sludge. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sludge drying system that collects sludge contained in waste water discharged from a home or factory and dries it.

  Treatment of sludge generated as a residue in domestic sewage or industrial wastewater treatment plants is an extremely important problem from the viewpoint of sanitary environment. The amount of sludge tends to increase with the development of industry and the improvement of living standards, and an immediate response is required in urban areas where population and factories are concentrated. When a large amount of sludge is collected, the problem of bad odor due to ammonia gas contained therein becomes prominent. In order to cope with this, the sludge is anaerobically and aerobically deodorized, and the air used for sludge drying is cooled, dehumidified, and heat-treated, and then used again for sludge drying. The technology is disclosed (for example, refer to Patent Document 1).

  In addition, as a technique for treating malodor generated from sludge, a technique for sending gas generating the malodor as combustion air to a combustion facility for burning garbage is disclosed (for example, see Patent Document 2). ). In this technique, in order to prevent corrosion of the constituent materials of the combustion facility by the odor gas, sulfur components are removed in advance from the gas sent to the combustion facility using activated carbon. This is intended to solve the problem of sludge odor and the maintenance of equipment.

JP 2001-70995 A Japanese Patent Application Laid-Open No. 7-119948 Japanese Patent Application Laid-Open No. 11-57995 JP 2000-51898 A

  In wastewater purification facilities such as sewage treatment plants that purify domestic wastewater and industrial wastewater, wastewater is purified to the extent that it can be discharged into rivers and the like by aeration technology. The waste water is appropriately treated as sludge, and the purified water is discharged into a river or the like. Here, the temperature of the discharged water from the wastewater purification facility is relatively high due to the influence of the heat energy obtained in the process of reaching the purification facility, that is, the use form as hot water at home or factory, etc. . When the amount of discharged water increases, the influence of the rise in the water temperature at the discharge destination becomes so large that it cannot be ignored. For example, environmental considerations are required, such as damaging the living environment of living organisms living in the river.

  On the other hand, the amount of water contained in the sludge is relatively high, and the amount of sludge after dehydration generated at sewage treatment plants throughout Japan is approximately 40,000 t / day. Since the amount of water reaches 32000t / day, if the sludge is used as the final treatment state of the sludge in the wastewater purification facility and transported to a predetermined facility outside the facility, there is a problem that the carrying out cost becomes extremely high. In order to reduce the load of carrying out, drying treatment or incineration treatment is performed in the wastewater purification facility. However, even if drying treatment or incineration treatment is performed, fuel (heavy oil, etc.) costs are incurred, and the cost burden cannot be ignored. Furthermore, an increase in environmental load due to carbon dioxide generated by the use of fuel is unavoidable, and environmental considerations are still required.

The present invention has been made in view of the above problems, and in treating sludge and effluent water generated in a wastewater purification facility, the environmental load is reduced as much as possible, and the sludge is dried. The purpose is to provide a sludge drying system.

  In order to solve the above-mentioned problems, in the sludge drying system according to the present invention, the intermediate treatment water in the purification process in the wastewater purification facility and the heat of the effluent water from which the wastewater is purified and discharged from the wastewater purification facility. Steam was generated using energy, and the sludge was dried using the steam. With such a configuration, it is possible to prepare a heat source required for sludge drying in the wastewater purification facility, so that the environmental load caused by the wastewater purification facility can be reduced as much as possible.

  More specifically, the present invention is a sludge drying system for separating waste water discharged from a home or factory into sludge and discharged water purified to such an extent that it can be discharged to the outside. In the wastewater purification facility to be used, heat is directly or indirectly supplied through the internally circulating refrigerant having the discharged water before being discharged to the outside and / or the intermediate treated water in the purification treatment process in the wastewater purification facility as a heat source. A steam generation unit that generates steam by performing exchange, and a steam generated by the steam generation unit is supplied, and the sludge separated from the discharged water is dried by the supplied steam, thereby drying sludge. A drying unit for generating

  The wastewater purification facility purifies wastewater sent from a place where wastewater is generated due to the use of water, such as a home (residential facility), a factory, a store, an office building, and farmland. By the purification, the waste water is separated into sludge and effluent water, and the effluent water is discharged into rivers and the like through a predetermined appropriate treatment. As the technology relating to this purification, for example, a conventional technology such as aeration performed so as to satisfy the water quality standard of the discharged water determined by the national or local public bodies can be adopted. Here, the temperature of the discharged water from the wastewater purification facility is relatively high compared to the water temperature of the discharge destination river. This is due to the usage pattern such as when the drainage is accepted by the drainage purification facility, and the drainage is used as warm water in a predetermined place. The trend of increasing the temperature of the discharged water is particularly remarkable in recent years, and is considered to be mainly due to the improvement of living standards and industrial development.

  Then, the sludge drying system which concerns on this invention performs the sludge drying process which paid its attention to the thermal energy which the intermediate treatment water of the purification treatment process in a waste water purification plant and the discharged water after this waste water is purified. Here, the intermediate treated water in the waste water purification facility can be adopted as long as it is in a state where it can be used as a heat source at any stage of purification. For example, a material that has been processed through a certain purification process such as aeration can be employed. Preferably, intermediate treated water that does not adversely affect the sludge drying system is preferable. Moreover, the production | generation of the dry sludge performed later is made easy by reducing the moisture content contained in waste_water | drain to some extent, and producing | generating sludge. This sludge generation may be realized by a concentration process or a dehydration process performed in a conventional wastewater purification facility, and is a treatment other than that, which is preferable for drying the sludge. It may be realized by processing.

  Moreover, a steam generation part produces | generates a vapor | steam using the thermal energy which discharge water has as mentioned above. This steam generation part has the refrigerant | coolant which circulates in it, and performs steam generation via a heat medium by performing heat exchange directly or indirectly between this refrigerant and discharge water. More specifically, the steam generation unit may include a heat pump device having a circulating refrigerant therein and capable of heat exchange, and a device for compressing the steam generated by the heat energy recovered by the heat pump device. Good. With such a configuration, even if the discharged water before discharge is at a temperature of about 10 degrees, it is possible to generate steam by condensing the thermal energy present there.

Then, the sludge is dried using the steam generated by the steam generator. By using this steam, efficient generation of dry sludge can be realized. As described above, according to the sludge drying system according to the present invention, the thermal energy possessed by the intermediate treatment water in the wastewater purification facility and the effluent water generated by the wastewater purification is aggregated in the form of steam and used for drying the sludge. By doing so, it becomes possible to produce dry sludge in a form that is closed to some extent in the wastewater purification facility. As a result, the temperature of the discharged water discharged from the wastewater purification facility can be lowered, and the environmental load on the discharge destination river or the like can be reduced. In addition, the generation of dry sludge using thermal energy obtained from the discharged water or intermediate treated water as the sludge treatment can also reduce the environmental burden.

  Here, in the sludge drying system, when the drying unit discharges condensed water that is a part of the supplied steam and has condensed steam after being used for drying sludge, the steam generation is performed. The unit generates steam as a heat source by performing direct heat recovery or indirect heat recovery of the retained heat amount of the condensed water discharged by the drying unit in addition to the discharged water and / or the intermediate treated water. You may comprise. In other words, the condensate generated from the steam supplied to generate dry sludge in the drying section is not thrown out of the system as it is, but is effectively reused in the system again for the generation of steam by the steam generation section. . Thereby, the steam in a steam generation part can be generated efficiently.

In addition, the steam generation unit performs direct heat recovery or indirect heat recovery of the heat held in the exhaust heat generated by the heat exchange of the heat held in the exhaust generated in the sludge drying process in the drying unit. In this case, steam may be generated as a heat source. That is, low-temperature exhaust water having a low temperature of 100 ° C. or less that has not been used so far can be effectively reused as steam by recovering heat in a steam generation unit including a heat pump device or the like.

  The drainage purification facility may be provided with a sludge incinerator for incinerating sludge. Then, when the sludge is incinerated by the sludge incinerator, the incineration heat exhaust water from which the heat quantity of the exhaust discharged from the sludge incinerator is recovered by a heat exchanger is discharged. In such a case, the steam generator collects the incineration heat exhaust hot water discharged from the sludge incinerator in addition to the discharged water and / or the intermediate treated water by direct heat recovery or indirect heat exchange. As a result, steam may be generated as a heat source. That is, when the incineration is performed by the sludge incinerator for sludge volume reduction treatment, the heat energy generated from the incineration heat exhaust water is not thrown out of the system as it is, but is generated by the steam generation unit. In the system, it is effectively used again. Thereby, the steam in a steam generation part can be generated efficiently. Furthermore, it is possible to suppress the environmental impact caused by the combustion heat that is discharged in the same quality as the environmental load due to the discharge of the discharge water at a temperature higher than the temperature of the discharge destination river. In particular, since the amount of combustion heat generated by an actual sludge incinerator is relatively large, effective use of the incineration heat is significant from the viewpoint of environmental protection.

  Here, in the sludge drying system, the drying unit is used in the sludge incinerator to incinerate the sludge by drying a part of the sludge using the steam generated by the steam generating unit. You may make it produce | generate the said dry sludge used as a fuel. The dried sludge produced by the drying section can also be a useful fuel resource depending on the organic content contained in it. Therefore, by treating the sludge generated in the wastewater purification facility using the dried sludge as fuel, the sludge can be treated in a form that is closed to some extent in the wastewater purification facility. According to such a configuration, it is possible to realize incineration volume reduction treatment of sludge generated in the facility without newly using a large amount of fossil fuel for sludge incineration, and further, drying as this fuel Unlike conventional fossil fuels, sludge is treated as so-called carbon-free, which is not counted in the discharge of carbon dioxide, so it can be said that it is a suitable fuel for wastewater purification facilities.

It should be noted that the dry sludge generated as the fuel produced by the sludge drying system according to the present invention is the steam generated by the steam generation unit, that is, the heat source generated in the waste water purification facility. This is a point generated based on. Until now, the thermal energy of the effluent water that had been discharged to the outside of rivers and the intermediate treatment water in the wastewater purification facility is recovered via the steam generator, and used as fuel for sludge combustion equipment. Recycling is a configuration that is not disclosed at all in conventional wastewater purification facilities, and the above-described effect of reducing the environmental load cannot be overlooked. The dried sludge is not only used in a sludge incinerator that incinerates sludge, but also can be used as a heat source in various facilities that require fuel, such as factories that are also sources of wastewater.

  In the sludge drying system described above, the wastewater purification facility is a wastewater purification facility that collects and purifies at least one of household wastewater and factory wastewater, or is provided in the factory facility from the factory facility. It may be a factory wastewater purification facility that purifies the factory wastewater. In addition, the sludge drying system according to the present invention can be meaningfully applied to various facilities that are discharge sources of wastewater containing sludge.

  Moreover, based on the technical idea mentioned above, it is also possible to grasp this invention from the side of the control apparatus for drying the sludge produced in a waste water purification facility, or the program for performing control with this control apparatus.

  It is possible to provide a sludge drying system that reduces the environmental load as much as possible when processing sludge and discharged water generated in a wastewater purification facility, and dries the sludge.

Typical flow of wastewater purification facilities Flow centering on a wastewater purification facility having a sludge drying system according to the present invention Heat energy recovery flow of condensed water of sludge drying system according to the present invention Heat energy recovery flow of drying heat exhaust water of the sludge drying system according to the present invention Heat energy recovery flow for incineration heat exhaust water of sludge drying system according to the present invention Schematic configuration of sludge incinerator

  An embodiment of a sludge drying system according to the present invention will be described in detail based on the drawings.

FIG. 1 shows a typical standard activated sludge process flow in a wastewater treatment facility. The sludge drying system 9 included in FIG. 1 is a system according to the present invention. Here, main wastewater flowing into the wastewater treatment facility 1 includes domestic wastewater 2 discharged from a residential facility such as a household and factory wastewater 3 discharged from a factory. The wastewater that has flowed in is initially subjected to the first settling of sludge contained therein in the settling basin 4. Then, the supernatant in the first sedimentation basin 4 is sent to the next aeration tank 5 for purification by so-called aeration. On the other hand, the residue in the first settling basin 4 generally becomes sludge containing about 1.0 to 2.0% by weight of solid content. When the aeration process is performed by the aeration tank 5, it is further sent to the final sedimentation basin 6, where sludge is settled. The residue in the final sedimentation basin 6 generally becomes sludge containing about 1.0% by weight of solid content. These sludges are sent to the sludge drying system 9 as sludge 8 after undergoing processing such as a concentration step and a dehydration step. In addition, the supernatant in the final sedimentation basin 6 is discharged from the discharge facility 7 to the river after being subjected to predetermined appropriate treatment so as to satisfy the discharge standard of the discharge water for the river discharge specified by the government. Will be executed.

As described above, the wastewater purification facility 1 collects water after being used in factories and residential facilities, that is, wastewater. Here, about the factory waste water 3, the water temperature tends to become comparatively high by having been used for the production activity in the factory. In addition, with regard to domestic wastewater, the water temperature tends to be relatively high due to use as hot water in a residential facility. As a result, the temperature of the wastewater collected in the wastewater purification facility 1 is also relatively high, and this tendency is more prominent particularly in urban areas where factories and residential facilities are densely populated and in recent years when industrialization is progressing.

In the waste water purification facility 1, the waste water is purified by performing aeration or the like, but the waste water temperature does not fluctuate greatly by these aerations. The rise in the temperature of inflowing industrial wastewater and domestic wastewater tends to affect the temperature rise of the discharged water that is finally discharged into the river. Especially in urban areas, the rise of the temperature of discharged water becomes remarkable due to the concentration of population and in the area where factories are established, due to industrial activities there. For example, with regard to the temperature of the discharged water discharged into the river from the wastewater purification facility in the center of Tokyo, there is a measurement result that the wastewater temperature has increased by about 5.5 degrees in the last 40 years, although there are fluctuations depending on the season. In particular, the rise in effluent temperature since the 1990s is remarkable. When drainage with such an elevated water temperature is discharged into the river as a result, the water temperature of the river rises, so the impact on the marine and lake ecosystems, especially in the river, is serious.

  Therefore, the sludge drying system 9 according to the present invention is provided in the drainage purification facility 1 shown in FIG. 2, and before the sludge drying system 9 sends the sludge drying system 9 to the discharge facility 7 and discharges it to the river. The heat energy of the discharged water is recovered, and the sludge collected in the wastewater purification facility 1 is dried using the recovered heat. In the drying unit 10 mounted on the sludge drying system 9, before the heat energy of the discharged water in the state where the sludge is removed from the drainage by the sedimentation basin or the aeration facility is discharged to the outside (river) by the discharge facility 7. Sludge is dried by extracting and using it. As shown in FIG. 2, the heat energy of the discharged water is recovered directly or indirectly by the steam generation unit 11 in the sludge drying system 9. Specifically, the steam generation unit 11 takes in effluent water (10 ° C. or more) as a heat source and directly or between the effluent water and the refrigerant by a heat pump system that repeatedly compresses and depressurizes the circulating refrigerant therein. Indirect heat exchange results in the generation of steam.

  Then, the steam generated by the steam generating unit 11 is sent to the drying unit 10 where it is used as an energy source for drying the sludge 8. In addition, the preferable specification of the vapor | steam supplied to the drying part 11 is 0.2 MPa or more in a gauge pressure. Since the steam generated in the steam generator 11 mainly uses the energy source for generation as effluent water, the electric power for driving the entire apparatus is circulated by the heat pump refrigerant in the steam generator 11. As a result, the input energy from the outside required for generating steam can be suppressed. As a result, it is possible to reduce the temperature of the discharged water to the river, and it is possible to cover part or all of the energy required for the drying treatment of the sludge in the waste water purification facility 1, so that the cost required for the sludge treatment is reduced. It can be kept low.

  Moreover, about the control of each apparatus of the drying part 10 mentioned above, and the steam generation part 11, and control between each apparatus (Movement of sludge, circulation of a refrigerant | coolant, generation | occurrence | production of steam, etc.), the sludge drying control part 13 in a sludge drying system. Executed by. This sludge drying control part 13 is implement | achieved by the computer program run on the computer provided in the sludge drying system 9 containing CPU, a memory, a hard disk, etc. which are not shown in figure.

A more detailed configuration of the sludge drying system 9 having such effects will be described with reference to FIGS. In the sludge drying system shown in FIG. 3, the drying unit 10 dries the sludge using the steam supplied from the steam generation unit 11 as a heat source. At this time, it is preferable that all the supplied steam is effectively used for drying sludge, but a part of the steam is discharged as condensed water after being used for drying. In this case, heat energy still remains even after the drying process in the drying unit 10, so that if condensed water is discharged as it is outside the system, energy loss will occur and the load on the external environment will also increase. Become. Therefore, in order to effectively use energy, the heat energy of the condensed water discharged from the drying unit 10 is directly or indirectly recovered and recirculated to the steam generation unit. Thereby, the thermal energy possessed by the condensed water is recovered.

Further, in the sludge drying system shown in FIG. 4, in addition to the above-mentioned discharged water and condensed water, the retained heat amount of the exhaust gas generated in the sludge drying process in the drying section is retained by the heat exchange. It shows that the heat quantity may be configured to generate steam as a heat source by performing direct heat recovery or indirect heat recovery. In other words, 100 ℃
The following low-temperature discharged hot water can also be effectively used again as steam by recovering heat with the heat pump system device of the steam generator 11. Specifically, the dry heat waste water generated by the heat exchanger is added to the discharged water before being discharged, or directly supplied to the steam generating unit 11 to generate steam by the steam generating unit.

  Moreover, in the sludge drying system 9 shown in FIG. 5, a part of produced | generated sludge is sent to the sludge incinerator 12, and is incinerated. The remaining sludge is similarly sent to the sludge drying system 9 to be dried sludge. Then, the produced | generated dry sludge is sent to the sludge incinerator 12, and is used as a fuel for incinerating sludge. About 80% of the sludge 8 after the dehydration treatment is water, but as shown in FIG. 5, if the ratio of the sludge supplied to the sludge incinerator 12 and the dry sludge is appropriately adjusted, the sludge is incinerated. Can be completed in the waste water purification facility 1.

  Here, the detailed structure of the sludge incinerator 12 is demonstrated based on FIG. The sludge incinerator 12 is provided with a combustion furnace 14 for performing sludge incineration processing. As described above, the sludge and the dried sludge are brought here and incinerated. The exhaust gas generated by the combustion flows to the first preheating device 15, the second preheating device 16, the cyclone device 17, the dust collector 18, the scrubber 19, and the smoke exhaust device 20 through the combustion furnace 14, and finally clean. Released into the atmosphere as air.

  The first preheating device 15 uses the heat of the exhaust gas flowing through the exhaust gas passage to preheat the combustion air of the combustion furnace in order to make the combustion in the combustion furnace 14 good. Further, when the second preheating device 16 releases the finally cleaned exhaust gas into the atmosphere, the second preheating device 16 prevents the exhaust gas in the smoke exhaust device 20 from condensing and forming white smoke. Reheating is performed. The cyclone device 17 provided on the downstream side of the second preheating device 16 separates and removes the incineration ash from the exhaust gas by using a centrifugal force generated by the cyclone generated inside the cyclone device 17. The incinerated ash that has been separated and removed is subjected to appropriate processing so as not to be accidentally released to the outside. The dust collector 18 provided on the downstream side of the cyclone device 17 removes finer particulate matter (PM) and the like that could not be removed by the cyclone device 17.

  Thereafter, the exhaust gas is sent to the scrubber 19, where scrubber water is supplied, the exhaust gas satisfies the atmospheric emission standard, and is released from the smoke exhaust device 20 into the atmosphere. Here, in the scrubber 19, the exhaust gas that has passed through the first preheating device 15, the second preheating device 16, the cyclone device 17, and the dust collector 18 is sent, but even at this time, the exhaust gas has a certain temperature. Therefore, the incineration heat exhaust water generated in the scrubber 19 is returned as a heat energy source of the steam generation part in the sludge drying system 9 (see FIG. 5). That is, a configuration is adopted in which the thermal energy of the incineration heat exhaust hot water is effectively used for generating steam that serves as a heat source for generating dry sludge in the drying unit 10.

By using the combustion heat generated by the incineration of sludge and dried sludge in this manner, the heat energy in the wastewater purification facility 1 can be effectively utilized by using it again for the generation of dried sludge through the steam generation unit 11. . In addition, as shown in FIG.
The problem of bad odor due to the odor can be avoided by sending the sludge to the sludge incinerator 12 including the odor generated when the dry sludge is generated.

Thus, heat energy is effectively recovered by the heat pump system device of the steam generation unit 11 included in the sludge drying system 9 for the low-temperature exhaust heat generated in the wastewater purification facility that has been difficult to recover until now, and the recovered heat By using the energy as a heat source for the drying unit 10, it is possible to complete the drying of the sludge by drying the sludge and generating the dried sludge. In other words, the drying of sludge can be realized without completely relying on fossil fuels transported from the outside, so that the burden on the environment can be reduced. Moreover, about the discharge water to a river, since the water temperature falls by the heat recovery in the steam generation part 11, warming of a river etc. can be prevented. According to the applicant's estimate, when this system is installed in sewage treatment plants nationwide, it is considered that the average discharge water from the sewage treatment plant to the river can be lowered by around 2.2 ° C.

And the dry sludge produced | generated via the sludge drying system 9 may be conveyed to the place finally disposed, or may be used as a fuel of the factory outside a waste water purification facility. Since the moisture content (32000 t / day) described above is eliminated by becoming dried sludge, the weight of the dried sludge is reduced, and the transportation cost can be suppressed. In addition, when the dried sludge is used in a factory, the dried sludge is not a fossil fuel and is a carbon-free fuel that does not count for carbon dioxide emissions. It is an effective fuel. If the moisture content in the dried sludge is 0% by weight, the dried sludge produced in the sludge drying system 9 is 8000 t / day. And since the calorie | heat amount of the produced | generated dry sludge is about 2000-5000 kcal / kg, it can understand easily that the dry sludge produced | generated with the said sludge drying system 9 is a useful heat source. Further, from the viewpoint of the odor of dried sludge and the long-term storage impossibility, it is also conceivable to carbonize the above-mentioned dried sludge and use it as carbonized sludge.

  In the above-described embodiments, the steam generation unit 11 exchanges heat with the discharged water before being discharged to the outside, thereby generating steam. Heat exchange may be performed with the intermediate treated water in the purification process existing in 1. That is, in order to produce dry sludge even when heat exchange is performed with the intermediate treated water before separation of the sludge 8 and before the complete purification treatment is completed, as in the case of heat exchange with the discharged water. It is possible to recover the necessary thermal energy. Of course, heat exchange may be performed between the discharged water and the intermediate treated water in the waste water purification facility.

DESCRIPTION OF SYMBOLS 1 ... Wastewater purification facility 2 ... Domestic wastewater 3 ... Factory wastewater 4 ... First sedimentation basin 5 ... Aeration tank 6 ... Final sedimentation basin 7 ... Discharge facility 8 ... Sludge DESCRIPTION OF SYMBOLS 9 ... Sludge drying system 10 ... Drying part 11 ... Steam generation part 12 ... Sludge incinerator 13 ... Sludge drying system control part 14 ... Combustion furnace 15 ... First preheating apparatus 16 ... Second preheating device 17 ... Cyclone device 18 ... Dust collector 19 ... Scrubber 20 ... Smoke exhaust device

Claims (6)

In the wastewater purification facility that purifies the wastewater by separating the wastewater discharged from homes and factories into sludge and the discharged water purified to the extent that it can be discharged to the outside, the discharged water before being discharged to the outside And / or a steam generation unit that generates steam by directly or indirectly performing heat exchange through an internally circulating refrigerant that has an intermediate treated water in the wastewater purification facility as a heat source;
A drying unit that generates dry sludge by supplying the steam generated by the steam generation unit and drying the sludge separated from the discharged water by the supplied steam;
A sludge drying system. The steam generating unit uses condensed water discharged after the supplied steam is used for drying the sludge in the drying unit as a heat source in addition to the discharged water and / or the intermediate treated water. Through direct or indirect heat exchange through the internally circulating refrigerant to generate steam,
The sludge drying system according to claim 1. The steam generating unit adds dry heat exhaust hot water, which is recovered by heat exchange of heat generated in the sludge drying process in the drying unit, to the effluent water and / or the intermediate treated water as a heat source. Heat is exchanged directly or indirectly through the internally circulating refrigerant of
The sludge drying system according to claim 1 or 2. When the wastewater purification facility is equipped with a sludge incinerator, the steam generating unit uses the heat discharged from the incineration heat exhaust water recovered from the heat quantity of the exhaust discharged from the sludge incinerator with a heat exchanger and / or the In addition to the intermediate treated water, it serves as a heat source, and generates heat by directly or indirectly exchanging heat through its internally circulating refrigerant.
The sludge drying system according to any one of claims 1 to 3. The drying unit uses the steam generated by the steam generation unit to dry a part of the sludge separated from the discharged water, and thereby the fuel for sludge incineration used in the sludge incinerator. Producing the dried sludge
The sludge drying system according to claim 4. The wastewater purification facility is a wastewater purification facility that collects and purifies at least one of household wastewater and factory wastewater, or is a wastewater purification facility that is provided in the factory facility and purifies the factory wastewater from the factory facility. A facility,
The sludge drying system according to any one of claims 1 to 5.

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