JP2022153736A - Sludge treatment equipment and sludge treatment method - Google Patents

Abstract

To provide sludge treatment equipment and a sludge treatment method thereof, for heating a sludge for solubilization, followed by effectively removing generated phosphoric acid.SOLUTION: A problem is solved by sludge treatment equipment and a sludge treatment method thereof, including: concentration means 20 assembled with a concentration tank 21 where an organic sludge is concentrated and separated into a concentration sludge C and a concentration wastewater R; addition means 60 for adding a coagulant to the concentration sludge C; and dewatering means 40 for dewatering a coagulant-added concentration sludge and separating it into a dewatering filtrate and a dewatered sludge E at 50°C or over and 100°C or under. The concentration tank 21 is assembled with a sludge inflow part 22 to which the organic sludge flows in; the dewatering filtrate is supplied to the sludge inflow part 22 or upstream of the sludge inflow part 22, flows in the concentration tank, and is discharged to the outside of the system as a concentration wastewater R.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a sludge treatment facility and a sludge treatment method.

Industrial wastewater, domestic wastewater, etc. are mostly treated by sewerage facilities and discharged into rivers and sea areas. The discharged water contains water pollutants, and effluent standards for these water pollutants are established according to the Water Pollution Control Law and other laws and regulations. Phosphorus, among water pollutants, causes red tide and the like due to eutrophication.

Since the phosphoric acid contained in the inflow water of sewerage facilities is a soluble component, it cannot be removed by normal water treatment, and is discharged into rivers and sea areas as effluent. Phosphoric acid is removed in sewerage facilities by chemical treatment in which inorganic chemicals such as iron salts and aluminum salts are added to remove as insoluble phosphorus compounds, or the AO method in which phosphoric acid is taken into activated sludge and removed. Biological treatments are common.

Activated sludge containing insolubilized phosphorus compounds or phosphoric acid is sent as excess sludge to a sludge treatment facility, undergoes processes such as concentration and dehydration, and is finally solid-liquid separated into dehydrated sludge and waste water. Most of the phosphoric acid is taken into the dehydrated sludge and discharged outside the system, but some of the phosphoric acid remaining in the wastewater is returned to the water treatment facility as return water, where inorganic chemicals are added again, It must be removed by the AO method. Therefore, as the concentration of phosphoric acid in the returned water increases, the amount of inorganic chemicals used or the power required for the AO method increases, leading to an increase in maintenance costs such as chemical costs and power costs.

Patent Document 1 discloses a technology related to sludge treatment equipment, and aims to obtain dehydrated sludge with a low water content by heating digested sludge and flocculating it using a polymer flocculant that exhibits a high dehydration effect. there is Reducing the moisture content of dehydrated sludge is generally desired in sewerage facilities because it makes it possible to reduce the amount of auxiliary fuel used in the subsequent incineration equipment, thereby reducing incineration costs and greenhouse gas emissions. is.

JP 2019-103952 A JP 2020-121253 A

However, in Patent Document 1, since the sludge is dehydrated after being heated in the dehydration equipment, the phosphoric acid eluted by heating is returned to the water treatment equipment together with the dehydrated filtrate. and consume more chemicals. Patent document 2 discloses a technique related to an organic sludge treatment facility using hot water.

Therefore, the problem to be solved by the present invention is to provide a sludge treatment facility and a sludge treatment method for efficiently removing phosphoric acid generated by heating and solubilizing sludge.

After extensive research, the present inventors have found that the phosphoric acid eluted by heating the sludge and the dehydrated filtrate containing the residual flocculant are allowed to flow into the front stage of the thickening tank, so that they are mixed with the organic sludge before thickening, and the organic The phosphoric acid in the sludge and the phosphoric acid eluted by heating react with the residual flocculant to become an insoluble phosphorous compound, which is taken into the solid matter side (sludge side). We obtained knowledge that the concentration can be reduced. The following aspects of the invention were completed based on this finding.

[First aspect]
thickening means having a thickening tank in which organic sludge is thickened and separated into thickened sludge and thickened wastewater;
An adding means for adding a flocculant to the thickened sludge;
Dewatering means for dewatering the thickened sludge to which the flocculant has been added and separating the dehydrated filtrate and the dehydrated sludge having a temperature of 50° C. or more and less than 100° C.;
The thickening tank has a sludge inflow part into which the organic sludge flows,
The dewatered filtrate is supplied to the sludge inflow part or an upstream part from the sludge inflow part, flows into the thickening tank, and is discharged out of the system as concentrated wastewater.
A sludge treatment facility characterized by:

[Second aspect]
a thickening step of thickening the organic sludge in a thickening tank in which the organic sludge is thickened and separated into thickened sludge and thickened wastewater;
An adding step of adding a flocculant to the thickened sludge;
A dehydration step of dewatering the thickened sludge to which the flocculant has been added and separating the dehydrated filtrate and the dehydrated sludge having a temperature of 50° C. or more and less than 100° C.,
The thickening tank has a sludge inflow part into which the organic sludge flows,
The dehydrated filtrate is supplied to the sludge inflow portion or to a portion upstream of the sludge inflow portion, flows into the thickening tank, and is discharged out of the system as concentrated wastewater.
A sludge treatment method characterized by:

In this embodiment, the thickened sludge to which the flocculant has been added is dewatered and separated into dehydrated filtrate and dehydrated sludge. Since the temperature of the dehydrated sludge is within the above range, the thickened sludge is solubilized, phosphoric acid is eluted, and the water content is relatively low. Flocculant may remain in the dewatered filtrate, and when this dewatered filtrate flows into the thickening tank, the phosphoric acid contained in the organic sludge before concentration and the phosphoric acid eluted by heating become the residual flocculant. It reacts with and becomes an insoluble phosphorus compound, so the concentration of phosphoric acid in the concentrated waste water is reduced.

ADVANTAGE OF THE INVENTION According to this invention, it becomes the sludge treatment equipment and sludge treatment method which heats sludge, makes it solubilize, and removes efficiently the phosphoric acid which generate|occur|produced.

It is a figure showing an example of an embodiment of the invention. FIG. 4 is a diagram representing another example of an embodiment of the invention; FIG. 4 is a diagram representing another example of an embodiment of the invention; FIG. 4 is a diagram representing another example of an embodiment of the invention; FIG. 4 is a diagram representing another example of an embodiment of the invention; FIG. 4 is a diagram representing another example of an embodiment of the invention; FIG. 4 is a diagram representing another example of an embodiment of the invention; It is a figure showing an example of an embodiment of the invention. It is a figure showing the result of an Example.

Next, a mode for carrying out the invention will be described. Note that this embodiment is an example of the present invention. The scope of the present invention is not limited to the scope of this embodiment.

(First embodiment)
The first embodiment of the sludge treatment facility according to the present invention includes a thickening means 20 having a thickening tank 21 in which organic sludge A is thickened and separated into thickened sludge C and thickened waste water R, and the thickened sludge C An adding means 60 for adding a flocculant, and a dewatering means 40 for dehydrating the thickened sludge to which the flocculant has been added and separating it into a dehydrated filtrate S and a dehydrated sludge E at 50 ° C. or more and less than 100 ° C. The thickening tank 21 has a sludge inflow portion 22 into which the organic sludge flows, and the dewatered filtrate S is supplied to the sludge inflow portion 22 or an upstream portion of the sludge inflow portion 22. , and discharged to the outside of the system as concentrated waste water R. In addition, if necessary, a process of flocculating the organic sludge may be performed prior to the process of concentrating the organic sludge.

(organic sludge)
The sludge treatment facility receives organic sludge A generated in a water treatment facility equipped with equipment for treating sewage, concentrates and dehydrates it into dehydrated sludge, and incinerates the dehydrated sludge. Organic sludge A includes raw sludge and activated sludge generated in water treatment facilities, and also includes microorganisms such as polyphosphate-accumulating bacteria. is dissolved in sewage in the form of ) is absorbed into the cells under aerobic conditions, and is released outside the cells under anaerobic conditions (intake and excretion).
The sludge concentration of the organic sludge A is 1 to 4%, depending on the treatment method of the water treatment facility.

(Concentration means)
The organic sludge A pumped from the water treatment facility to the sludge treatment facility through the pumping passage L1 is thickened by the thickening means 20 . The thickening means 20 separates the organic sludge A into a thickened sludge C and a thickened waste water R by subjecting the organic sludge A to a thickening process. The thickening means 20 includes a sludge inflow part 22 into which the organic sludge A flows, a thickening tank 21 that receives and thickens the inflowed organic sludge A, and a sludge outflow part 23 that flows out the thickened sludge C obtained by thickening to the downstream. , a drainage unit for discharging concentrated waste water R generated in the concentration process. The downstream end of the pressure feed channel L1 is connected to the sludge inflow portion 22, and the downstream end of the filtrate channel L4 through which the dehydrated filtrate S discharged from the dehydration means 40 flows is connected to the sludge inflow portion 22 or the It is connected upstream of the sludge inflow part 22 . The dehydrated filtrate S is guided through the filtrate flow path L4, supplied to the sludge inflow portion 22 or a portion upstream of the sludge inflow portion 22, and flows into the thickening tank 21. A pump P3 for sending the dehydrated filtrate S is preferably provided in the filtrate flow path L4. Here, the upstream portion from the sludge inflow portion 22 may be the pumping flow path L1, and when the aggregation means 10 is provided upstream of the concentration means 20, the front stage portion of the aggregation means 10, and the water treatment equipment. It may be a pumping channel that connects the aggregation means 10 . In addition, when the flocculation means 10 is provided, the organic sludge A flows from the water treatment equipment through the pumped flow path, flows into the flocculation means 10, and is flocculated to become flocculated sludge. 20 and flows into the thickening tank 21 from the sludge inlet 22 .

The concentrating means 20 is not particularly limited, and a general one can be applied. This apparatus is provided with a bottomed cylindrical thickening tank centered on a longitudinally extending axis in which the inflowed organic sludge A and/or dehydrated filtrate S, that is, the material to be treated, is held. The treated material is supplied into the thickening tank from the top of the thickening tank. The cylindrical body of the thickening tank is a filter screen made of wedge wire, punching metal, etc., except for the shielding part, and a jacket-like drainage chamber is arranged around the filter screen. there is Inside the filter screen, there is provided a cylindrical rotating shaft that rotates around the axis extending along the axis of the thickening tank, and screw blades spirally arranged along the rotating shaft. In addition, a rotary drive means such as a motor for rotating a rotary shaft is disposed in the upper part of the thickening tank and connected to the rotary shaft.

The sludge inflow part 22 can be provided in the upper part of the thickening tank 21 , and the sludge outflow part 23 can be provided in the lower part (bottom part) of the thickening tank 21 . When the dehydrated filtrate S is allowed to flow into the concentrating tank 21, the position into which the dehydrated filtrate S is introduced can be appropriately selected. For example, the position into which the dehydrated filtrate S is introduced may be the sludge inflow section 22 or a position where the organic sludge A has been concentrated about halfway, that is, the middle section of the thickening tank 21, the sludge outflow section 23, or the like. can. However, it is desirable that the position into which the dehydrated filtrate S is introduced is the sludge inflow section 22 . If the inflow position of the dehydrated filtrate S is the sludge inflow part 22, the dehydrated filtrate S in which the coagulant remains is mixed with the organic sludge A before being subjected to the concentration treatment, and the coagulant dissolves in the organic sludge A. Since it reacts with phosphoric acid to form an insoluble phosphorus compound, phosphoric acid in organic sludge can be reduced. Regarding this point, if the dehydrated filtrate S was allowed to flow into the middle part of the thickening tank 21, the concentrated wastewater generated by the concentration process from the sludge inflow part 22 to the middle part contained a large amount of phosphoric acid. As a result, the waste water discharged out of the system contains a large amount of phosphoric acid. Considering this point of view, the position into which the dehydrated filtrate S flows may of course be the sludge inflow portion 22 or the pumping passage L1 or the aggregation means 10 upstream of the sludge inflow portion 22 .

The thickened sludge C thickened by the thickening means 20 has a sludge concentration of 4 to 10%.

The thickened sludge C discharged from the thickening means 20 flows through the sludge flow path L2, which is a flow path connecting the thickening means 20 and the dehydrating means 40 installed downstream thereof, and is sent to the dehydrating means 40 . The thickened sludge C can be force-fed in the sludge flow path L2 by applying pressure using a pump P1 provided in the sludge flow path L2 in consideration of the frictional resistance of the sludge.

The dehydrated filtrate S flows into the concentration tank 21 and is discharged outside the system as concentrated waste water R. Here, the sewage that has flowed into the water treatment facility is generally discharged from upstream to downstream through a receiving well, a primary sedimentation tank, a reaction tank, and a final sedimentation tank into rivers, the sea, and the like. For example, by supplying the concentrated wastewater R to the inflow part of the primary sedimentation tank of the water treatment facility or to the upstream part of the primary sedimentation tank, it is treated together with the inflowing sewage, and finally discharged into rivers, the sea, etc. It will be done.

(addition means)
When the thickened sludge C is dehydrated by the dewatering means 40, a dehydrated filtrate containing a large amount of phosphoric acid is generated. Here, if a flocculant is added to the thickened sludge C prior to dehydration by the dewatering means 40, the phosphoric acid reacts with the flocculant and becomes an insoluble phosphorus compound, which migrates to the thickened sludge side (solid matter side). , the concentration of phosphoric acid contained in the dewatered filtrate can be reduced. As the coagulant addition means 60, for example, a container containing the coagulant and an arbitrary point of the sludge flow path L2 are connected by a pipe for adding the coagulant, and a stirrer or the like is provided at the arbitrary point. can be mentioned. An appropriate amount of coagulant is allowed to flow from the container to the sludge flow path L2 according to the flow rate of the thickened sludge C, and after the thickened sludge C mixed with the coagulant is stirred, it is allowed to flow into the dehydration means 40.

Examples of flocculants include inorganic flocculants such as polyaluminum chloride (PAC) and polyferric sulfate, organic flocculants, anionic or nonionic polymer flocculants, and cationic polymer flocculants. can. In particular, ferric sulfate and polyaluminum chloride remain in the dewatering filtrate and react with phosphoric acid in the organic sludge to become insoluble phosphorous compounds. preferred because it works

Conventionally, in order to reduce the water content of sludge, a process of adding a flocculant to thickened sludge has been performed, and the addition rate of the flocculant in the thickened sludge was about 10 to 35% by mass. On the other hand, in the present embodiment, the addition rate of the coagulant in the thickened sludge is 1 to 15% by mass, preferably 2 to 10% by mass. In this embodiment, by heating the sludge, the reactivity of the sludge and the flocculant increases, so it is possible to reduce the water content of the dewatered sludge without adding a flocculant as much as in the conventional case. .

(Dehydration means)
The dehydration means 40 includes a sludge inflow portion into which thickened sludge C flows, a sludge outflow portion into which dewatered sludge that has undergone dewatering treatment flows out, a discharge portion into which dehydrated filtrate is discharged as discharged liquid F, and a dehydrated filtrate that circulates. It has a circulating water outlet for sending water to the upstream side of the sludge treatment facility, and a dehydrator. The thickened sludge C flowing into the dewatering means 40 is dewatered and separated into dehydrated sludge E and dehydrated filtrate. The dehydrated filtrate may be discharged outside the system as it is as the effluent F, but the effluent F usually contains phosphoric acid, and when it is returned to the water treatment equipment, the phosphoric acid in the water treatment equipment processing will be overloaded.

In order to reduce the load for removing phosphorus in the water treatment facility, in the present embodiment, the entire amount or part of the dehydrated filtrate, preferably the entire amount of the dehydrated filtrate, is allowed to flow into the concentrating means 20, so that the water treatment facility We are trying to reduce the concentration of phosphate ions contained in the returned water.

As the dewatering means 40, a device equipped with a dehydrator such as a centrifugal dehydrator, a screw press, a filter press and a belt press can be used.

The dehydrated sludge E dehydrated by the dewatering means 40 can be treated without the need for supplementary fuel in the post-process incineration equipment if the moisture content is adjusted to about 70%, depending on the combustible content of the sludge. be able to.

The temperature of the dewatered sludge E should be 50°C or higher and lower than 100°C. Preferably, the temperature varies depending on the type of sludge of the organic sludge A, but in the case of mixed raw sludge, the temperature is 50°C to 80°C, in the case of medium temperature digested sludge, it is 60°C to 80°C, and in the case of high temperature digested sludge, it is 70°C to 90°C. °C or below. If the temperature is less than 50°C, the moisture content of the dehydrated sludge E will be high, requiring auxiliary fuel for the incineration facility, which may lead to an increase in maintenance and management costs. If the temperature is 100°C or higher, the temperature of the sludge is too high, making facility management difficult.

The temperature of the dehydrated sludge E can be measured, for example, by a temperature sensor provided at or near the sludge outlet of the dehydrated sludge in the dehydrator provided in the dewatering means 40 . The temperature sensor may be contact or non-contact with the dewatered sludge.

The temperature of the dehydrated filtrate can be measured, for example, by a temperature sensor provided at or near the discharge portion of the dehydrated filtrate in the dehydrator provided in the dehydrating means 40 . The temperature sensor may be contact or non-contact with the dewatered filtrate.

When the heated dewatered filtrate flows into the concentrating means 20, the organic sludge in the thickening tank 21 is mixed with the dehydrated filtrate, heated, and solubilized. In addition to the phosphoric acid contained in the organic sludge, phosphoric acid is eluted by solubilization. The acid concentration will be low.

(heating)
In order to obtain the dewatered sludge E having a temperature of 50°C or more and less than 100°C, it is preferable to provide the heating means 50 in the sludge treatment facility. The position where the heating means 50 is provided is not limited as long as the dehydrated sludge E that is heated is obtained. Here, the heating means 50 for directly or indirectly heating the thickened sludge C to which the flocculant has been added will be described as an example.

As the heating means 50, specifically, a method of directly supplying hot water or steam to the thickened sludge C to heat it, a heat exchanger is provided in the flow of the thickened sludge C, and a heat medium is flowed to indirectly A method of heating, a method of installing a heater thrown into the flow of thickened sludge C for heating, and the like can be exemplified.

When hot water is used for the heating means 50, it is possible to use hot water generated from flue gas treatment tower wastewater of sludge incineration equipment provided in the sludge treatment equipment, scrubber wastewater of sludge drying equipment, or digestion gas generators.

Sludge is solubilized by heating, and the water content is lowered, making it easier to incinerate. In addition, since the solubilized sludge has a low viscosity, it has a low frictional resistance and can be easily transported.

The mass balance of sludge in this embodiment is approximately as follows. Assuming that the organic sludge flowing into the sludge treatment facility is 100% by mass, dewatered sludge is 22-24% by mass, and the remainder is discharged outside the system as concentrated wastewater. In this respect, the dehydrated sludge is 25 to 27% by mass in conventional sludge treatment facilities without heating means.

Further, according to this embodiment having the heating means, the flow rate of the organic sludge flowing into the concentrating means 20 is 5 to 60 m ³ /h, whereas the dehydrated filtrate flowing into the concentrating means 20 flow rate is 0.2 to 35 m ³ /h.

(Second embodiment)
A second embodiment will be described below with reference to FIG. The second embodiment is different from the first embodiment in that aggregation means 10 is provided upstream of concentration means 20 . As the flocculation means 10, one having a bottomed cylindrical flocculation tank, which is supplied with the organic sludge A and the flocculant and has a center axis extending in the vertical direction, can be exemplified. A rotating shaft along the central axis and a stirring blade are attached along the rotating shaft, and the rotating shaft and the stirring blade are rotated by a rotary drive means such as a motor provided at the top of the flocculation tank to organic sludge. A stirring means for stirring A and the flocculant is provided. The organic sludge stirred by this stirring means flows out of the aggregation means 10 and is supplied to the concentration means 20 . The flocculated organic sludge B can be particularly called flocculated sludge, and its sludge concentration is 1 to 4%.

(Third Embodiment)
A third embodiment will be described with reference to FIG. 3rd Embodiment is a form provided with the aggregation means 10, the concentration means 20, and the dehydration means 40, and the heating means 50 was provided in two places. The number of heating means 50 differs between the third embodiment and the second embodiment. The first heating means 50 heats the thickened sludge C that has flowed into the dewatering means 40 , and the second heating means 50 heats the organic sludge that has flowed into the thickening means 20 .

By providing the heating means 50 in the thickening means 20, the organic sludge flowing into the thickening means 20 is solubilized and concentrated by the heating means 50, so that the sludge concentration of the thickened sludge C discharged from the thickening means 20 is increased. . Since the thickened sludge C is further heated by the heating means 50 provided in the downstream dehydration means 40, the dehydrated sludge E has a lower moisture content and is suitable for incineration.

The thickened sludge C heated by the second heating means 50 and discharged from the thickening means has a temperature of 50°C or more and less than 100°C.

(Fourth embodiment)
A fourth embodiment will be described with reference to FIG. The fourth embodiment differs from the second embodiment in that the heating means 50 provided in the dehydrating means 40 in the second embodiment is provided in the concentrating means 20 .

(Fifth embodiment)
A fifth embodiment will be described with reference to FIG. The fifth embodiment is a form in which a second heating means 50 is further provided in the sludge flow path L2 of the second embodiment. Since the thickened sludge C flowing through the sludge flow path L2 is thickened, it has high viscosity and frictional resistance. However, since the thickened sludge C is heated by the heating means 50 and solubilized, its viscosity is lowered and it becomes easier to send it to the dewatering means 40 . The heating means 50 can be provided anywhere in the sludge flow path L2. In particular, if the addition means 60 is provided on the upstream side of the location where the addition means 60 is provided, the solubilized thickened sludge is mixed with the flocculant and is easily mixed, which is preferable.

(Sixth embodiment)
A sixth embodiment will be described with reference to FIG. In the sixth embodiment, in addition to the second embodiment, the thickening means 30, the sludge flow path L3 in which the sludge outflow part of the thickening means 30 and the sludge inflow part of the dewatering means 40 are connected, and the thickening means 30 It comprises a sludge flow path L5 to which the drainage part and the filtrate flow path L4 are connected, a pump P2 provided in the sludge flow path L3, and a pump P4 provided in the sludge flow path L5. Concentration means 30 similar to concentration means 20 can be used.

By providing the above means and equipment, the first thickening means having a thickening tank in which the organic sludge is thickened and separated into the first thickened sludge and the first thickened effluent, and the first thickened sludge directly or A heating means for indirectly heating, a second thickening means for separating the heated first thickened sludge into a second thickened sludge and a second thickened effluent, an adding means for adding a flocculant to the second thickened sludge, Dewatering means for dewatering the second thickened sludge to which the flocculant has been added and separating the dehydrated filtrate and the dehydrated sludge having a temperature of 50° C. or more and less than 100° C., wherein the thickening tank comprises the organic sludge. The dewatered filtrate and the second concentrated wastewater flow into the thickening tank from the sludge inflow portion and are discharged out of the system as the first concentrated wastewater. , It becomes a sludge treatment facility characterized by.

(Seventh embodiment)
A seventh embodiment will be described with reference to FIG. The seventh embodiment differs from the second embodiment in that the heating means 50 provided in the dehydrating means 40 in the second embodiment is provided upstream or upstream of the aggregation means 10 . By supplying the organic sludge A heated by the heating means 50 to the flocculating means 10, the reactivity between the sludge and the flocculant increases, so the amount of the flocculant added by the flocculating means 10 can be reduced. . The temperature of the organic sludge heated by the heating means 50 and supplied to the aggregation means 10 is 50°C or more and less than 100°C.

In the second embodiment, polyferric sulfate is used as the flocculant of the adding means 60, and the thickened sludge is heated by a direct heating method with hot water as the heating means 50 to treat the organic sludge (original sludge). and measured the water content of the dewatered sludge. The measurement was performed by changing the addition rate of ferric polysulfate and the temperature of the dehydrated sludge. FIG. 9 shows the results of the moisture content of the dehydrated sludge.

From the results, when the added amount of ferric polysulfate is constant, the water content of the dewatered sludge decreases as the temperature increases.

Also, organic sludge (original sludge) was treated using the same second embodiment, and the concentration of phosphoric acid in each treatment step was measured. The treatment conditions include the presence or absence of the heating means 50 for heating the thickened sludge by a method of direct heating with hot water, the presence or absence of the addition means 60 using polyferric sulfate, the supply of the dehydrated filtrate to the sludge inflow part 22 (the dehydrated filtrate circulation) was changed. Table 1 shows the results of calculating the amount of phosphoric acid (g/h) obtained from the flow rate (m ³ /h) and the concentration of phosphoric acid (g/m ³ ) in each treatment step.

As a result, since phosphoric acid is eluted by heat-treating the sludge, the amount of phosphoric acid in the returned water increased compared to the conventional method. The acid is removed and is below the limit of detection (ND).

INDUSTRIAL APPLICABILITY The present invention can be used as a sludge treatment facility and a sludge treatment method.

Claims (9)

thickening means having a thickening tank in which organic sludge is thickened and separated into thickened sludge and thickened wastewater;
An adding means for adding a flocculant to the thickened sludge;
Dewatering means for dewatering the thickened sludge to which the flocculant has been added and separating the dehydrated filtrate and the dehydrated sludge having a temperature of 50° C. or more and less than 100° C.;
The thickening tank has a sludge inflow part into which the organic sludge flows,
The dewatered filtrate is supplied to the sludge inflow part or an upstream part from the sludge inflow part, flows into the thickening tank, and is discharged out of the system as concentrated wastewater.
A sludge treatment facility characterized by: The entire amount of the dehydrated filtrate is flowed into the thickening tank,
The sludge treatment facility according to claim 1. The dehydrated filtrate has a temperature of 50° C. or more and less than 100° C.
The sludge treatment facility according to claim 1. Having a heating means for directly or indirectly heating the thickened sludge to which the flocculant has been added,
The sludge treatment facility according to claim 1. The adding means is added so that the coagulant is contained in the concentrated sludge in an amount of 1 to 15% by mass.
The sludge treatment facility according to claim 1. Having a heating means for directly or indirectly heating the thickened sludge,
The adding means adds a flocculant to the thickened sludge heated by the heating means,
The sludge treatment facility according to claim 1. a flocculating means for flocculating organic sludge having a temperature of 50° C. or more and less than 100° C. to obtain flocculated sludge;
thickening means having a thickening tank in which the flocculated sludge is thickened and separated into thickened sludge and thickened wastewater;
An adding means for adding a flocculant to the thickened sludge;
Dewatering means for dewatering the thickened sludge to which the flocculant has been added and separating the dehydrated filtrate and the dehydrated sludge having a temperature of 50° C. or more and less than 100° C.;
The thickening tank includes a sludge inflow part into which the flocculated sludge flows,
The dewatered filtrate is supplied to the sludge inflow part or an upstream part from the sludge inflow part, flows into the thickening tank, and is discharged out of the system as concentrated wastewater.
A sludge treatment facility characterized by: a first thickening means having a thickening tank in which organic sludge is thickened and separated into first thickened sludge and first thickened wastewater;
heating means for directly or indirectly heating the first thickened sludge;
a second thickening means for separating the heated first thickened sludge into a second thickened sludge and a second thickened effluent;
addition means for adding a flocculant to the second thickened sludge;
Dewatering means for dewatering the second thickened sludge to which the flocculant has been added to separate the dehydrated filtrate and the dehydrated sludge having a temperature of 50° C. or more and less than 100° C.;
The thickening tank has a sludge inflow part into which the organic sludge flows,
The dewatered filtrate and the second concentrated effluent are supplied to the sludge inflow part or to an upstream part of the sludge inflow part, flow into the thickening tank, and are discharged out of the system as the first concentrated effluent.
A sludge treatment facility characterized by: a thickening step of thickening the organic sludge in a thickening tank in which the organic sludge is thickened and separated into thickened sludge and thickened wastewater;
An adding step of adding a flocculant to the thickened sludge;
A dehydration step of dewatering the thickened sludge to which the flocculant has been added and separating the dehydrated filtrate and the dehydrated sludge having a temperature of 50° C. or more and less than 100° C.,
The thickening tank has a sludge inflow part into which the organic sludge flows,
The dehydrated filtrate is supplied to the sludge inflow portion or to a portion upstream of the sludge inflow portion, flows into the thickening tank, and is discharged out of the system as concentrated wastewater.
A sludge treatment method characterized by:

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