JP2014193442A - Method and installation for treatment of organic sludge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of treating organic sludge which can reduce the operation cost and improve the recovery rate of phosphorus.SOLUTION: A method of treating organic sludge includes a mixing step of mixing organic sludge with an organic solvent A which is liquid at ordinary temperature and ordinary pressure to dissolve the cell membrane partially, a dehydration step of supplying the organic sludge B mixed with the organic solvent to a dehydration portion of a dehydration machine 5 to dehydrate so as to separate into a filtrate C and dehydrated sludge D and a melting treatment step of treating the dehydrated sludge D in a melting installation 8.

Description

  The present invention relates to a processing method and processing equipment for organic sludge containing organic substances generated from, for example, sewage and food industry.

  Conventionally, when organic sludge is mechanically squeezed and dehydrated, it is difficult to dehydrate the water in the cell membrane of organic matter in organic sludge (referred to as encapsulated water). It was generally difficult to make it 60 to 80% or less.

  As a conventional organic sludge treatment method, for example, as shown in FIG. 11, the organic sludge having a solid concentration of about 2 to 5% is dehydrated by the dehydrator 101, and the moisture content of the organic sludge is reduced to about 80%. Next, the organic sludge is heated and dried by the heating dryer 102 to evaporate water in the organic sludge. Thereby, dry sludge having a moisture content reduced to about 30% is obtained. Then, dry sludge is incinerated (or melted) with incineration equipment 103 (or melting equipment) to reduce the volume of sludge, and at the same time, extract and recover phosphorus, a useful component contained in incinerated ash (or molten solidified product). It is used for fertilizer.

  As another organic sludge treatment method, for example, as shown in FIG. 12, the organic sludge is supplied to the reaction can 110, steam is blown into the reaction can 110, and the organic cell membrane in the organic sludge under high temperature and high pressure. To lower the molecular weight. Thereafter, the organic sludge is dehydrated by the dehydrator 111, and the filtrate and dehydrated sludge are taken out from the dehydrator 111. Among these, dehydrated sludge has a moisture content reduced to about 40%, and the dehydrated sludge is incinerated by the incineration facility 112 to extract and recover phosphorus contained in the incineration ash. In addition, about the method of performing a high temperature / high pressure process using water vapor | steam as mentioned above, it describes in the following patent document 1, for example.

Japanese Patent No. 493759

  However, in the conventional format shown in FIG. 11, since the water in the organic sludge is evaporated using the heating dryer 102, there is a problem that the energy consumed by the heating dryer 102 is increased and the operation cost is increased. .

  In the conventional format shown in FIG. 12, in the reactor 110, the cell membrane of organic matter in organic sludge is finely cut and reduced in molecular weight under high temperature and high pressure, so when dewatering the organic sludge with a dehydrator, The rate at which phosphorus constituting the cell membrane escapes from the solid and moves into the filtrate together with the low molecular weight cell membrane. As a result, the concentration of phosphorus contained in the dewatered sludge decreases, and there is a problem that the amount of phosphorus recovered from the incinerated ash decreases.

  An object of this invention is to provide the processing method and processing equipment of the organic sludge which can reduce an operating cost and can improve the recovery rate of phosphorus.

In order to achieve the above object, the organic sludge treatment method according to the first invention comprises a mixing step of dissolving a part of a cell membrane by mixing organic sludge and an organic solvent that is liquid at normal temperature and pressure,
A dehydration step in which organic sludge mixed with an organic solvent is supplied to a dehydrator of a dehydrator to dehydrate, and separated into dehydrated sludge and filtrate;
It has an incineration or melting treatment step of treating dehydrated sludge with an incineration facility or a melting facility.

  According to this, in the mixing step, part of the cell membrane of the organic substance in the organic sludge is dissolved and damaged by the organic solvent, so that the contained water is easily discharged from the damaged portion of the cell membrane. Therefore, in the dehydration process, it becomes possible to dehydrate the contained water using a dehydrator, and easily reduce the water content of organic sludge until incineration or melting treatment is possible without adding energy. Can do.

  In addition, the cell membrane of the organic matter in the organic sludge is not cut finely and reduced in molecular weight, but only part of the cell membrane is dissolved and damaged by the organic solvent, so it is transferred to the filtrate during the dehydration process. The amount of phosphorus to be reduced is reduced, and accordingly, the concentration of phosphorus contained in the dewatered sludge is improved. Thereby, the ratio of phosphorus contained in the incinerated ash generated in the incineration or melting treatment step or in the molten solidified product is increased, and the recovery rate of phosphorus is improved.

In the method for treating organic sludge in the second invention, the organic solvent has a boiling point lower than that of water,
The organic solvent contained in the organic sludge or filtrate is recovered.
According to this, an organic solvent can be collect | recovered and reused, the usage-amount of an organic solvent is reduced, and an operating cost is reduced.

The method for treating organic sludge according to the third aspect of the invention is to heat the filtrate using the heat of the incineration facility or the melting facility and separate and recover the organic solvent from the filtrate.
According to this, since the filtrate is heated by effectively using the excess heat of the incineration facility or the melting facility, the operation cost is further reduced.

In the method for treating organic sludge according to the fourth invention, the melting facility includes a cooling water tank for cooling the molten dewatered sludge with water,
The filtrate is heated using the heat of the cooling water tank.

According to this, since the filtrate is heated using the extra heat of the cooling water tank effectively, the operating cost is further reduced.
In the dewatering step, the organic sludge treatment method according to the fifth aspect of the present invention uses the heat of the incineration facility or the melting facility to add the organic sludge in the dewatering section to a predetermined temperature that is higher than the boiling point of the organic solvent and lower than the boiling point of water. Warm and vaporize organic solvent mixed in organic sludge,
The vaporized organic solvent is discharged from the dehydration unit and collected.

  According to this, in the dehydration process, the organic sludge mixed in the organic sludge is vaporized and recovered by heating the organic sludge in the dewatering section to a predetermined temperature that is higher than the boiling point of the organic solvent and lower than the boiling point of water. However, the water contained in the organic sludge is kept in a liquid state without being vaporized. For this reason, without evaporating water, water can be separated from organic sludge while being in a liquid state, energy required for dehydration is reduced, and operation costs are reduced.

In addition, since the organic sludge is heated by effectively using excess heat from the incineration facility or the melting facility, the operating cost is further reduced.
The treatment equipment for organic sludge according to the sixth invention comprises a mixing tank for mixing organic sludge and an organic solvent that is liquid at room temperature and normal pressure and has a boiling point lower than that of water,
A dehydrator that dehydrates organic sludge mixed with an organic solvent and separates it into dehydrated sludge and filtrate;
A heated distiller that heat-distills the filtrate removed from the dehydrator to separate and recover the organic solvent from the filtrate;
It has an incineration facility or a melting facility for incinerating or melting the dewatered sludge taken out from the dehydrator.

  According to this, by mixing the organic sludge and the organic solvent in the mixing tank, part of the cell membrane is dissolved and damaged, so that the contained water is easily discharged from the damaged part of the cell membrane. Thereafter, by dehydrating the organic sludge mixed with the organic solvent with a dehydrator, it becomes possible to dehydrate the contained water using the dehydrator, and the water content of the organic sludge can be easily reduced.

  In addition, the cell membrane of organic matter in organic sludge is not cut finely and reduced in molecular weight, but only a part of the cell membrane is dissolved and damaged by the organic solvent, so the amount of phosphorus transferred into the filtrate Is reduced, and the concentration of phosphorus contained in the dewatered sludge is improved. Thereby, the ratio of phosphorus contained in the incinerated ash generated in the incineration facility or in the molten solidified product generated in the melting facility is increased, and the recovery rate of phosphorus is improved.

  Further, since water contained in the organic sludge can be separated from the organic sludge while being in a liquid state without evaporating the water, the energy required for dehydration is reduced and the operating cost is reduced. Furthermore, the organic solvent contained in the filtrate can be recovered and reused, and the operating cost can be reduced by reducing the amount of organic solvent used.

In the seventh aspect of the present invention, the organic sludge treatment facility heats the filtrate using the heat of the incineration facility or the melting facility.
According to this, since the filtrate is heated by effectively using the excess heat of the incineration facility or the melting facility, the operation cost is further reduced.

In the organic sludge treatment facility according to the eighth aspect of the invention, the dehydrator heats the organic sludge to a predetermined temperature not lower than the boiling point of the organic solvent and lower than the boiling point of water, and vaporizes the organic solvent mixed with the organic sludge. Having a heating means
The heating means warms the organic sludge using the heat of the incineration facility or the melting facility.

  According to this, since the organic sludge is heated by effectively using the excess heat of the incineration facility or the melting facility, the operation cost is further reduced.

  As described above, according to the present invention, the operating cost can be reduced and the phosphorus recovery rate can be improved.

It is a figure which shows typically the processing equipment of the organic sludge in the 1st Embodiment of this invention. It is a side view of the filter press of the processing equipment. It is an exploded perspective view showing the composition of a filter press same as the above. FIG. 3 is a partially enlarged side view of the filter press. It is sectional drawing of the filter plate of a filter press, Comprising: The state which is performing the filtration process is shown. It is sectional drawing of the filter plate of a filter press, Comprising: The state which is performing the pressing process is shown. It is sectional drawing of the filter plate of a filter press, Comprising: The state which is performing the drying process is shown. It is a figure of the melting equipment of a processing equipment. It is a figure which shows typically the processing equipment of the organic sludge in the 2nd Embodiment of this invention. It is a figure of the incineration equipment of a processing equipment. It is a figure which shows the processing method of the conventional organic sludge. It is a figure which shows the processing method of the conventional organic sludge.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
In 1st Embodiment, FIG. 1 is a figure which shows typically the processing equipment 1 of the organic sludge in a sewage treatment. According to this, the concentration machine 3 which concentrates the organic sludge denitrified in the denitrification tank 2, the mixing tank 4 which mixes the alcohol solvent A into the concentrated organic sludge, and the organic sludge in which the alcohol solvent A is mixed. Endless filter cloth traveling filter press 5 (an example of a dehydrator) that dehydrates B into filtrate C and dehydrated sludge D, a condenser 6 that returns the vaporized alcohol solvent A to a liquid, and a filter press The filtrate C taken out from 5 is heated and distilled to separate and recover the liquid alcohol solvent A from the filtrate C, and the dehydrated sludge D taken out from the filter press 5 is melted to reduce the volume. And a melting facility 8.

  The alcohol solvent A is an example of a volatile organic solvent that is liquid under normal temperature and normal pressure (25 ° C., 1 atm), and methanol and ethanol are used as specific examples. The alcohol solvent A has a boiling point lower than that of water (100 ° C.), for example, 65 ° C. for methanol and 78 ° C. for ethanol. Here, the boiling point means a standard boiling point at 1 atm.

For the concentrator 3, for example, a belt concentrator is used. The mixing tank 4 is equipped with a stirrer for stirring and mixing the organic sludge and the alcohol solvent A.
As shown in FIG. 2, the filter press 5 includes a fixed frame 15, a movable frame 16 that can be moved toward and away from the fixed frame 15, and a plurality of frames that are arranged between the frames 15 and 16 so as to be moved toward and away from each other. A filter plate 17, an endless filter cloth 18, an opening / closing device 19 that opens and closes the filter plate 17 by moving the filter plates 17 close to each other, a filter cloth drive device 29 that causes the filter cloth 18 to travel in one direction E, Heating means 20 for heating the organic sludge B to a predetermined temperature not lower than the boiling point of the alcohol solvent A and lower than the boiling point of water to vaporize the alcohol solvent A mixed in the organic sludge B (see FIG. 5). And have. As shown in FIG. 3, the filter cloth 18 is stretched around a roller 21 and arranged in an inverted U shape between the filter plates 17. Between each filter plate 17, a filter chamber 22 (an example of a dewatering unit) is formed between a pair of filter cloths 18 facing each other. The opening / closing device 19 has a cylinder 23 (see FIG. 2) that moves the movable frame 16.

  As shown in FIG. 4, the fixed frame 15 and the filter plate 17 at one end are connected by a link 24, and similarly, the movable frame 16 and the filter plate 17 at the other end are connected by a link 25. 17 are connected by a link mechanism 26.

  As shown in FIGS. 5 to 7, each filter plate 17 is formed with a recess 27 and a heating passage 32 that are open on one side of the front and back surfaces, and a diaphragm 28 is provided in the recess 27. Each filter plate 17 is connected with a hot water supply path 70 for supplying the hot water 10 to each filter plate 17 and a hot water discharge path 71 for discharging the hot water 10 from each filter plate 17.

  The hot water supply path 70 has branched first and second hot water supply paths 30 and 33. Of these, the first hot water supply path 30 supplies hot water 10 to expand the diaphragm 28, and the second hot water supply path 33 supplies hot water 10 to the heating passage 32.

  The warm water discharge path 71 has branched first and second warm water discharge paths 31 and 34. Among these, the first warm water discharge path 31 discharges the warm water 10 to contract the diaphragm 28, and the second warm water discharge path 34 discharges the warm water 10 from the heating passage 32. The heating means 20 includes a heating passage 32, a hot water supply path 70, and a hot water discharge path 71.

  As shown in FIG. 3, each filter plate 17 is formed with a sludge injection passage 36 for injecting organic sludge B into the filter chamber 22. Further, between the filter plates 17, a base member 37 (feed piece) is supported by the link mechanism 26. Each base member 37 is formed with a branch passage (not shown) branched from the sludge injection passage 36 and leading to the filter chamber 22. Each filter plate 17 is formed with a filtrate discharge passage 40 for discharging the filtrate C generated from the organic sludge B squeezed in the filter chamber 22.

As shown in FIG. 1, between the mixing tank 4 and the filter press 5, a sludge supply path 45 that supplies the organic sludge B in the mixing tank 4 to the filter press 5 is connected.
The heating distiller 7 heats the filtrate C taken out from the filter press 5 to a predetermined temperature to evaporate the alcohol solvent A in the filtrate C and separate it from the filtrate C, and cools the evaporated alcohol solvent A. Thus, the liquid alcohol solvent A is recovered.

  Connected between the filter press 5 and the heating distiller 7 is a filtrate recovery path 54 for sending the filtrate C discharged from the filter press 5 to the heating distiller 7. The filtrate collection path 54 is provided with a filtrate collection valve 55. Further, the filtrate recovery path 54 joins the first solvent recovery path 56 a branched from the filtrate recovery path 54 and communicated with the inlet of the condenser 6 and the filtrate recovery path 54 from the outlet of the condenser 6. A two-solvent recovery path 56b is connected. A solvent recovery valve 57 is provided in the first solvent recovery path 56a.

  Between the mixing tank 4 and the heating distiller 7, a first solvent return path 58 for returning the liquid alcohol solvent A separated and recovered from the filtrate C in the heating distiller 7 to the mixing tank 4 is provided. Yes. Further, a second solvent return path 59 for returning the liquid alcohol solvent A to the denitrification tank 2 is provided between the denitrification tank 2 and the heating distiller 7. The second solvent return path 59 is branched from the first solvent return path 58, and the first and second solvent return paths 58 and 59 are provided with first and second return valves 60 and 61, respectively.

  As shown in FIGS. 1 and 8, the melting facility 8 includes a melting furnace 64, a burner 65, a sludge charging unit 66 for dropping and feeding the dewatered sludge D taken out from the filter press 5 into the melting furnace 64, and a melting And a cooling water tank 67 provided in the lower part of the furnace 64. The cooling water tank 67 cools and solidifies the dewatered sludge D that has been melted in the melting furnace 64 to form slag, and cooling water 68 is stored therein.

  The heating means 20 of the filter press 5 heats the organic sludge B using the heat of the melting equipment 8. That is, the dewatered sludge D melted into slag falls into the cooling water tank 67, and the dehydrated sludge D is cooled and solidified by the water 68 in the cooling water tank 67, so that the temperature of the water 68 in the cooling water tank 67 rises. In order to use the water 68 as the warm water 10 of the warming means 20, the warm water supply path 70 and the warm water discharge path 71 of the warming means 20 are connected to the cooling water tank 67.

  Similarly, the heating distiller 7 heats and distills the filtrate C using the heat of the melting equipment 8. That is, a supply path 73 for supplying water 68 in the cooling water tank 67 to the heating distiller 7 as a heating source, and a discharge path for discharging the water 68 used as the heating source from the heating distiller 7 and returning it to the cooling water tank 67. 74 is provided.

Hereinafter, the operation of the above configuration will be described.
A method for dewatering organic sludge using the treatment facility 1 will be described below.
In advance, the cylinder 23 of the opening / closing device 19 of the filter press 5 is actuated to bring the movable frame 16 closer to the fixed frame 15, and the filter plates 17 are closed as shown in FIG. Further, the hot water 10 flows from the hot water supply path 70 to the second hot water supply path 33, is supplied from the second hot water supply path 33 to the heating passage 32 of each filter plate 17, and is supplied from the heating passage 32 to the second hot water supply path 33. It discharges to the warm water discharge path 34 and flows from the second warm water discharge path 34 to the warm water discharge path 71. As a result, the hot water 10 is kept flowing through the heating passage 32, and the inside of the filter chamber 22 is heated to a predetermined temperature by the hot water 10 in the heating passage 32.

  The predetermined temperature is a temperature not lower than the boiling point of the alcohol solvent A and lower than the boiling point of water. For example, when the alcohol solvent A is methanol, the first predetermined temperature is not lower than 65 ° C. and lower than 100 ° C. In the case of ethanol, the first predetermined temperature is 78 ° C. or higher and less than 100 ° C.

  Then, as shown in FIG. 1, the filtrate recovery valve 55 and the first return valve 60 are opened, the solvent recovery valve 57 and the second return valve 61 are closed, and denitrification is performed in the denitrification tank 2. The organic sludge is concentrated by the concentrator 3, and in the mixing tank 4, a mixing step of mixing the liquid organic solvent A with the concentrated organic sludge is performed. At this time, if the recovered alcohol solvent A is insufficient, a new alcohol solvent A is additionally used. Thereafter, the organic sludge B mixed with the alcohol-based solvent A is supplied from the mixing tank 4 through the sludge supply path 45 to the filter press 5 and is subjected to a dehydration process comprising the following filtration process, pressing process and drying process. Dehydrated.

  That is, in the filtration step, the organic sludge B passes through the sludge supply passage 45, passes through the sludge injection passages 36 of the filter plates 17 of the filter press 5, passes through the branch passages of the base members 37 from the sludge injection passage 36, It is injected into the filter chamber 22. Thereby, as shown in FIG. 5, the organic sludge B is filtered in each filter chamber 22. At this time, since the filter chamber 22 is heated to a predetermined temperature by the hot water 10 passing through the heating passage 32, the organic sludge B injected into the filter chamber 22 is also heated to the predetermined temperature.

  After performing the filtration step, as shown in FIG. 6, the hot water 10 is supplied from the first hot water supply path 30 to each filter plate 17 and continues to pass through the inner space 13 of the diaphragm 28. Thereby, the diaphragm 28 expand | swells and the organic sludge B in the filter chamber 22 is squeezed and dehydrated. Even when such a pressing process is performed, the organic sludge B in the filter chamber 22 is heated to a predetermined temperature by continuously passing the hot water 10 from the second hot water supply path 33 to the heating path 32. Has been. That is, the organic sludge B continues to be heated to a predetermined temperature while remaining in the filter chamber 22.

  The filtrate C generated in the filtration step and the squeezing step is discharged through the filtrate discharge passage 40 of each filter plate 17 and, as shown in FIG. Sent. The filtrate C contains water and a liquid alcohol solvent A.

  Furthermore, after performing the said pressing process, as shown in FIG. 7, in the state which passed the warm water 10 from the 2nd warm water supply path 33 to the heating path 32, the diaphragm 28 is passed from the 1st warm water supply path 30. The supply of the hot water 10 to the inner space 13 is stopped, the hot water 10 in the inner space 13 of the diaphragm 28 is discharged to the first hot water discharge path 31, and the inner space 13 is emptied. Thereby, the diaphragm 28 contracts and is separated from the filter cloth 18, and a drying space 14 is formed between the diaphragm 28 and the filter cloth 18. At this time, since the organic sludge B in the filter chamber 22 is heated to a predetermined temperature by the hot water 10 in the warming passage 32, the alcohol solvent A mixed in the organic sludge B is vaporized and dried. To be taken out.

  The vaporized alcohol solvent A is mainly recovered in the drying step as described above, but it can be recovered by suction in the filtration step and the squeezing step, and is recovered only in the drying step. Recovery efficiency is further improved.

  When performing such a drying step, as shown in FIG. 1, the filtrate recovery valve 55 is closed and the solvent recovery valve 57 is opened, and the vaporized alcohol solvent A is exhausted (not shown) or the like. Aspirate and discharge from the filter chamber 22. As a result, the evaporated alcoholic solvent A passes through the filtrate discharge passage 40 from the drying space 14 of each filter plate 17, is discharged to the outside of the filter press 5, and is branched from the filtrate collection passage 54 to be the first solvent. It passes through the recovery path 56a and is supplied to the condenser 6. The alcohol-based solvent A supplied to the condenser 6 in this way is condensed from gas to liquid, and then merged into the filtrate recovery path 54 through the second solvent recovery path 56b and sent to the heating still 7. .

  The filtrate C discharged from the filter press 5 in the filtration step and the squeezing step, and the liquid alcohol solvent A obtained by condensing in the condenser 6 after being discharged from the filter press 5 in the drying step are heated. They are collected in the distiller 7 and collectively heated to a predetermined temperature and distilled. Thereby, the alcoholic solvent A contained in the filtrate C is vaporized and separated from water, and then the alcoholic solvent A is cooled and returned from the gas to the liquid. In this way, the filtrate C is separated into water and a liquid alcohol solvent A, water is drained to the outside from the heating distiller 7, and the liquid alcohol solvent A is recovered and heated to the heat distiller 7. To the mixing tank 4 through the first solvent return path 58 and repeatedly reused.

  Thereafter, the cylinder 23 of the opening / closing device 19 of the filter press 5 is actuated to move the movable frame 16 away from the fixed frame 15 and open between the filter plates 17 as shown in FIG. Then, the filter cloth drive device 29 causes the filter cloth 18 to travel in one direction E, and the dewatered sludge D (dehydrated cake) is discharged downward from the filter chamber 22 between the filter cloths 18.

  In this way, a melting treatment step is performed on the dewatered sludge D discharged to the outside of the filter press 5. That is, as shown in FIGS. 1 and 8, the dewatered sludge D is transferred to the sludge charging section 66 of the melting facility 8, charged into the melting furnace 64 from the sludge charging section 66, and melted in the melting furnace 64. It becomes slag, falls into the cooling water tank 67, is cooled and solidified with water 68, and becomes a molten solidified product.

  In the method of treating organic sludge as described above, as shown in FIG. 1, in the mixing step, a liquid alcohol solvent A is mixed with the organic sludge in the mixing tank 4 so that one cell membrane of organic matter in the organic sludge is mixed. Since the part is dissolved and damaged by the alcoholic solvent A, the contained water is easily discharged from the damaged part of the cell membrane. Therefore, in the subsequent dehydration step, the inclusion water can be dehydrated by squeezing dehydration using the filter press 5, and the water content of the organic sludge can be easily reduced.

  That is, almost no energy is evaporated from the outside of the processing equipment 1 during dehydration, and further, in the melting equipment 8, the ash content in the sludge is made into molten slag without adding external fuel in addition to the energy required for melting. The water content of the organic sludge can be lowered until it is possible, and the energy required for the treatment facility 1 is reduced.

  In the mixing step, the cell membrane of the organic matter in the organic sludge is not cut finely and reduced in molecular weight, but only a part of the cell membrane is dissolved and damaged by the alcohol solvent A, so that the filter press In the dehydration process using 5, the amount of phosphorus transferred into the filtrate C is reduced, and the concentration of phosphorus contained in the dewatered sludge D is increased accordingly. Thereby, the ratio of the phosphorus contained in the molten solidified product of the dewatered sludge D generated in the melting treatment step is increased, and the recovery rate of phosphorus is improved.

  Moreover, as shown in FIG. 7, in the drying process of the filter press 5, since the organic sludge B in the filter chamber 22 is heated to a predetermined temperature, alcohol mixed with the organic sludge B in the filter chamber 22 is used. Although the system solvent A is vaporized, the water in the organic sludge B is hardly vaporized and kept in a liquid state. For this reason, the alcoholic solvent A can be separated from the organic sludge B with almost no water evaporated, the energy required to recover the alcoholic solvent A is reduced, and the operating cost of the treatment facility 1 is reduced.

  In the dehydration process as described above, as shown in FIG. 8, the water 68 in the cooling water tank 67 of the melting facility 8 is used as the hot water 10 for heating the organic sludge B in the filter chamber 22 to a predetermined temperature. Since it uses, the extra heat of the cooling water tank 67 can be used effectively, and the organic sludge B can be heated by the heating means 20. Similarly, as shown in FIG. 1, by supplying the water 68 in the cooling water tank 67 whose temperature has risen to the heating distiller 7 from the supply path 73, the excess heat of the cooling water tank 67 can be effectively used and filtered. The liquid C can be heated and distilled with the heating still 7. Thereby, the operating cost of the processing facility 1 is further reduced.

  In addition, when the temperature of the water 68 in the cooling water tank 67 is too high compared with the predetermined temperature, the cooling water is injected into the hot water supply path 70 and the temperature of the hot water 10 supplied to the filter press 5 is lowered to an appropriate temperature. Also good.

As an example of the first embodiment, the daily organic sludge dehydrated using the treatment facility 1 is 903 (m ³ / day), and the phosphorus concentration contained in the organic sludge is 461 (mg / L). In this case, the amount of the phosphorus substance contained in the organic sludge treated per day is 417 (kg / day), and the daily flow rate of the alcohol solvent A is 167 (m ³ / day). The amount of the phosphorus substance contained in the liquid C was 18.5 (kg / day), and the amount of the phosphorus substance contained in the dewatered sludge D was 398.5 (kg / day). Therefore, about 4.4% of the amount of phosphorus substances contained in the organic sludge is transferred and lost (lost) in the filtrate C, but the remaining 95.6% remains in the dehydrated sludge D. The recovery rate of phosphorus is improved in the melting process.

On the other hand, as in the conventional method shown in FIG. 12, in the method of performing high-temperature and high-pressure treatment using steam, the organic sludge per day to be dehydrated is 600 (m ³ / day). When the phosphorus concentration contained in the organic sludge is 613 (mg / L), the amount of the phosphorus substance contained in the organic sludge treated per day is 368 (kg / day) and is contained in the filtrate. The amount of phosphorus substance was 67 (kg / day), and the amount of phosphorus substance contained in the dewatered sludge was 301 (kg / day). Accordingly, about 18% of the amount of phosphorus substance contained in the organic sludge is lost in the filtrate, and the remaining 82% remains in the dewatered sludge D. In comparison, the phosphorus recovery rate decreased.

  In the first embodiment, as shown in FIG. 1, the first return valve 60 is opened, the second return valve 61 is closed, and the recovered liquid alcohol-based solvent A is supplied to the first solvent return passage. 58, the first return valve 60 is closed, the second return valve 61 is opened, and the recovered liquid alcohol-based solvent A is removed through the second solvent return passage 59. 2 may be returned. In this case, since the alcohol solvent A becomes a nutrient source for the denitrifying bacteria in the denitrification tank 2, the alcohol solvent A can be used effectively without being wasted.

(Second Embodiment)
In the second embodiment, instead of the melting facility 8, as shown in FIG. 9, an incineration facility 77 for incinerating the dewatered sludge D taken out from the filter press 5 is provided. As in the first embodiment, the heat generated in the incineration facility 77 is used to heat the organic sludge B in the filter chamber 22 of the filter press 5 to a predetermined temperature, and the filtrate C is heated and distilled. 7 heat distill.

  As shown in FIG. 10, the incineration facility 77 is discharged from the incinerator 78 for incinerating the dewatered sludge D, the wet smoke tower 79 for cleaning the exhaust gas G discharged from the incinerator 78, and the wet smoke tower 79. And a chimney 80 for releasing the exhaust gas G into the atmosphere. The wet smoke tower 79 has an exhaust gas inlet 79 a and an outlet 79 b, and inside the wet smoke tower 79, a spray device 82 for spraying water 81 onto the exhaust gas G, and water 81 sprayed from the spray device 82. And a water storage tank 84 for storing smoke as drainage 83.

  That is, in order to use the smoke washing wastewater 83 stored in the water storage tank 84 as the hot water 10 of the heating means 20, the hot water supply path 70 and the hot water discharge path 71 of the heating means 20 are connected to the water storage tank 84. ing. Similarly, the supply path 73 for supplying the smoke washing wastewater 83 in the water storage tank 84 to the heating distiller 7 as a heating source, and the smoke washing wastewater 83 used as the heating source are discharged from the heating distiller 7 and stored in the water storage tank 84. A discharge path 74 is provided for returning to the inside.

  According to this, the incineration process is performed on the dewatered sludge D discharged to the outside of the filter press 5. In the incineration process, the dewatered sludge D is incinerated in the incinerator 78. Phosphorus contained in incineration ash is extracted and recovered for use as fertilizer. Further, the exhaust gas G generated during incineration flows from the incinerator 78 into the wet smoke tower 79, and water 81 is sprayed from the spray device 82 onto the exhaust gas G in the wet smoke tower 79, whereby the exhaust gas G enters the exhaust gas G. Removes ash, impurities and harmful substances. Thereafter, the exhaust gas G is discharged from the outlet 79b of the wet smoke cleaning tower 79 to the chimney 80, and is discharged from the chimney 80 into the atmosphere.

  Further, in the dehydration step of dewatering the organic sludge B using the filter press 5, as shown in FIG. 10, as the warm water 10 for heating the organic sludge B in the filter chamber 22 to a predetermined temperature, the incinerator 77 Since the smoke washing drain 83 in the water storage tank 84 is used, the excess heat of the water storage tank 84 can be used effectively and the organic sludge B can be heated by the heating means 20. Similarly, as shown in FIG. 9, the smoke washing waste water 83 in the water storage tank 84 is supplied to the heating distiller 7 from the supply path 73, so that the excess heat of the water storage tank 84 can be effectively used, and the filtrate C Can be heated and distilled with a heating still 7. Thereby, the operating cost of the processing facility 1 is further reduced.

In each of the above embodiments, the filter press 5 is used as an example of a dehydrator. However, as another example, a screw press or a belt press may be used.
In each of the above embodiments, the alcohol solvent A is used as an example of the organic solvent, but acetone or hexane may be used.

  In each of the above embodiments, the vaporized alcohol solvent A is returned to a liquid by the condenser 6, but the alcohol solvent A may be returned to the mixing tank 4 or the denitrification tank 2 while remaining in a gas state. However, returning in the liquid state is more convenient because the amount of the alcohol solvent A can be easily controlled.

  In each of the above embodiments, the excess heat of the cooling water tank 67 or the water storage tank 84 is effectively used, but the heat of the exhaust gas of the melting equipment 8 or the incineration equipment 77 is recovered and used by a heat exchanger or a boiler. You can also In addition, when the heat of the melting furnace 64 or the incinerator 78 is insufficient, for example, when the furnace is out of operation or at the time of startup, for example, the heat required from other heat sources such as an auxiliary boiler is used in combination. May be secured.

  In the first embodiment, the water 68 in the cooling water tank 67 is directly introduced into the filter press 5 as the hot water 10, but the water 68 in the cooling water tank 67 is used as a heat source for heating the hot water 10. Also good. This is because if the water 68 in the cooling water tank 67 is dirty or corrosive, if the water 68 in the cooling water tank 67 is directly introduced into the filter press 5 as the hot water 10, the filter press 5 may be adversely affected. This is a better way to prevent such adverse effects.

  Similarly, in the second embodiment, the smoke washing drainage 83 of the water storage tank 84 is directly introduced into the filter press 5 as the hot water 10, but the water washing tank 84 is washed as a heat source for heating the hot water 10. Smoke drainage 83 may be used.

1 Processing equipment 4 Mixing tank 5 Filter press (dehydrator)
7 Heating distiller 8 Melting facility 20 Heating means 22 Filtration chamber (dehydration part)
67 Cooling water tank 68 Water 77 Incineration equipment A Alcohol solvent (organic solvent)
B Organic sludge C Filtrate D Dehydrated sludge

Claims (8)

Mixing step of dissolving a part of cell membrane by mixing organic sludge and organic solvent which is liquid under normal temperature and normal pressure;
A dehydration step in which organic sludge mixed with an organic solvent is supplied to a dehydrator of a dehydrator to dehydrate, and separated into dehydrated sludge and filtrate;
An incineration or melting treatment step of treating dehydrated sludge with an incineration facility or a melting facility, and a method for treating organic sludge. The organic solvent has a lower boiling point than water,
2. The organic sludge treatment method according to claim 1, wherein an organic solvent contained in the organic sludge or filtrate is recovered. The method for treating organic sludge according to claim 2, wherein the filtrate is heated using heat of an incineration facility or a melting facility, and an organic solvent is separated and recovered from the filtrate. The melting facility includes a cooling water tank that cools the molten dewatered sludge with water,
The method for treating organic sludge according to claim 3, wherein the filtrate is heated using heat of the cooling water tank. In the dehydration process, the organic sludge in the dewatering section is heated to a predetermined temperature not lower than the boiling point of the organic solvent and lower than the boiling point of water using the heat of the incineration facility or the melting facility, and mixed with the organic sludge. Vaporize
The method for treating organic sludge according to any one of claims 2 to 4, wherein the vaporized organic solvent is discharged from the dehydration unit and collected. A mixing tank for mixing organic sludge and an organic solvent that is liquid at room temperature and normal pressure and has a boiling point lower than that of water;
A dehydrator that dehydrates organic sludge mixed with an organic solvent and separates it into dehydrated sludge and filtrate;
A heated distiller that heat-distills the filtrate removed from the dehydrator to separate and recover the organic solvent from the filtrate;
An organic sludge treatment facility comprising an incineration facility or a melting facility for incinerating or melting dehydrated sludge taken out from a dehydrator. 7. The organic sludge treatment facility according to claim 6, wherein the heating distiller heats the filtrate using heat of the incineration facility or the melting facility. The dehydrator has a heating means for heating the organic sludge to a predetermined temperature which is equal to or higher than the boiling point of the organic solvent and lower than the boiling point of water, and vaporizes the organic solvent mixed in the organic sludge.
The organic sludge treatment facility according to claim 6 or 7, wherein the heating means heats the organic sludge using heat of the incineration facility or the melting facility.

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