JPH0640929B2 - ▲ Ro ▼ Overconcentrator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a device for overconcentrating sludge generated in water treatment, industrial water treatment, sewage treatment, human waste treatment, industrial wastewater treatment and the like. In particular, the present invention relates to an overconcentrator used as a pretreatment for dehydrating sludge in a sun drying bed, a pressure dehydrator, a centrifugal dehydrator, a freeze-thaw machine, or the like.

[Conventional technology]

Conventionally, water treatment, industrial water treatment, sewage treatment, night soil treatment,
When dewatering sludge generated by industrial wastewater treatment, etc., an inorganic coagulant such as iron salt, lime, or a dewatering aid such as a polymer coagulant is added to the sludge, and the underwater granulation dehydrator, vacuum over-machine, addition Dewatering was performed with a dehydrator such as a pressurizer, a centrifugal dehydrator, and a belt press type dehydrator. In recent years, especially in the fields of clean water treatment, industrial water treatment, etc., cases of dehydration treatment using a sun drying bed without a chemical injection or a pressure dehydrator are increasing. When performing such dehydration treatment, the concentration of sludge when supplied to a sun drying bed or a pressure dehydrator is very important. If the sludge concentration is low, the treatment on the sun drying bed or pressure dehydrator will be performed. The efficiency is significantly reduced. Conventionally, sedimentation methods such as thickeners (precipitation methods) have been used for pre-concentration of sludge, but recently the proportion of components that are difficult to concentrate such as organic substances and aluminum hydroxide in sludge has increased, and sedimentation methods are sufficient. There are many things that can not be concentrated.

Therefore, for example, an overconcentrator as shown in FIG. 2 has been used. That is, in the closed tank 1, a horizontal partition plate 2 divides and forms a sludge concentrating section 3 and a liquid collecting section 4 for collecting liquid on the upper part thereof, and in the sludge concentrating section 3, a sludge inflow pipe 6 equipped with a sludge inflow valve 5 is formed. Sludge inflow pipe 6 is connected to raw sludge storage tank 7
It is connected to the discharge side of the sludge pump 8 that supplies the raw sludge. A liquid outlet pipe 10 having a liquid valve 9 in the liquid collecting part 4,
An air inflow pipe 12 connected to the air source equipment via an air inflow valve 11 and a vacuum pipe 15 connected to the suction side of a vacuum pump 14 via a vacuum check valve 13 are connected in series. Further, in the sludge thickening section 3, a cylindrical filter element (hereinafter simply referred to as element) 16 having a cloth wound around the outer periphery of the support body and having one end opened and the other end closed is disposed, and the vicinity of each open end is The liquid, which is fixed to the partition plate 2 and permeates into the element 16, flows into the liquid collecting section 4 through the open end. In addition, the upper part of the sludge thickening section 3 has an air vent valve 1
The air vent pipe 18 having the air vent valve 17 is connected to the air collecting pipe 4 and the air vent pipe 18 'having the air vent valve 17' is also connected to the inside of the liquid collecting section 4.

Further, a concentrated sludge discharge part 19 is formed in the lower part of the closed tank 1, and a concentrated sludge discharge pipe 21 equipped with a concentrated sludge discharge valve 20 is continuously provided.

In the figure, reference numeral 22 is a raw sludge return pipe that includes a raw sludge return valve 23 and connects the inside of the closed tank 1 and the raw sludge storage tank 7.

In such an over-concentrator, the raw sludge stored in the raw sludge storage tank 7 by the sludge pump 8 is supplied from the sludge inflow pipe 6 to the sludge condensing unit 3 in the closed tank 1, but the raw sludge is fed by the sludge pump 8. By press-fitting (or depressurizing the liquid collecting part 4 side with the vacuum pump 14), sludge adheres to the outside of the element 16 and is concentrated by the differential pressure generated inside and outside the element 16, while the liquid enters the inside of the element 16. It permeates and is collected in the liquid collecting part 4, and flows out from the liquid outflow pipe 10.

By the above operation, when the sludge is attached to the outside of the element 16 and the sludge is concentrated to a predetermined concentration, the supply of the original sludge is stopped,
The raw sludge return valve 23 is opened, the air vent valve 17 is opened to open the atmosphere, the unconcentrated sludge in the sludge enrichment section 3 is returned from the raw sludge return pipe 22 to the raw sludge storage tank 7, and then the raw sludge return valve 23 is closed. Using the air inflow valve 11, the air 16 is blown into the element 16 from the air inflow pipe 12 through the liquid collecting section 4.
When the thickened sludge adhering to the outside is peeled off, the thickened sludge falls into the thickened sludge discharge section 19, the thickened sludge discharge valve 20 is opened, and the thickened sludge is discharged from the thickened sludge discharge pipe 21. After such a process of peeling and discharging the concentrated sludge, the concentrated sludge discharge valve 20
Is closed, the atmosphere in the sludge thickening unit 3 is shut off, and the sludge pump 8 again fills the sludge thickening unit 3 with the sludge in the raw sludge storage tank 7, and then the above-described overconcentration is performed.

[Problems to be Solved by the Invention]

By the way, when the unconcentrated sludge in the sludge enrichment section 3 is returned to the original sludge storage tank 7 before the concentrated sludge adhering to the outside of the element 16 is peeled off, a vacuum is applied in the liquid collection section 4 by the vacuum pump 14. It is kept. This is element 1
This is because the concentrated sludge adhered to No. 6 is not cracked or separated.

However, when the unconcentrated sludge is returned to the original sludge storage tank 7, if the degree of vacuum in the liquid collecting section 4 is too strong, cracks will occur in the concentrated sludge adhering to the element 16, and if the degree of vacuum is weak. Partial exfoliation of concentrated sludge occurs. In such a state, when the concentrated sludge is subsequently peeled off by air blowing, the blowout flows out from a crack or a portion having less resistance in the peeling portion, the entire inside of the element 16 cannot be blown uniformly, and the whole concentrated sludge is peeled off. Becomes defective. Therefore, in order to eliminate such a defect due to the fluctuation of the degree of vacuum, the vacuum pump 14 is provided with a vacuum tank or the like to perform control for stabilizing the vacuum pressure, but the equipment becomes complicated and complicated operation is required. Was also forced.

The present invention eliminates the need for a conventional vacuum pump, maintains a stable degree of vacuum in the liquid collection section, improves the separation of concentrated sludge, facilitates maintenance, and reduces the power cost. It is intended to be provided.

[Means for Solving the Problems]

The present invention partitions and forms a sludge concentrating section and a liquid collecting section in which a sludge inflow pipe is connected in a tank, and a cylindrical filter element having one end opened and the other end closed in the sludge concentrating section is disposed,
A closed tank whose open end communicates with the liquid collecting section, and an air release valve at the upper part that seals the lower end with water at a constant water level so that it can be shut off, and a vacuum that can generate a predetermined vacuum pressure by lowering the internal water level. An over-concentrating device comprising a forming tank, wherein the liquid collecting section of the closed tank and the vacuum forming tank are connected by a liquid pipe.

[Action]

 The operation of the present invention having the above configuration will be described with reference to FIG.

The operation of over-concentrating the sludge may be the operation in the conventional apparatus of the second illustrated example or any other operation such as Japanese Patent Application No. 1-271546, but in the present invention, the conventional vacuum pump 1
A vacuum forming tank 31 is provided instead of 4, and is connected to the liquid collecting section 4 of the closed tank 1 by a liquid pipe 32.

Therefore, in the overconcentration operation, the liquid flowing out from the liquid collecting part 4 through the liquid pipe 32 is flown into and stored in the vacuum forming tank 31 which is blocked from the water sealing part and opened to the atmosphere, and the water level is a predetermined high water level ( HWL, Homm), the flow of the liquid into the vacuum forming tank 31 is stopped and the liquid is discharged from the liquid outflow pipe 10.

Next, when the sludge is concentrated outside the element 16 in the closed tank 1 to a predetermined concentration, the supply of the original sludge is stopped, and the lower end of the vacuum forming tank 31 is connected to the water sealing portion. The water level in the interior falls and the low water level (LW
L, Hmm), a vacuum is formed in the vacuum forming tank 31 due to the water level drop, and when the inside of the liquid collecting portion 4 of the closed tank 1 is cut off from the atmosphere to communicate with the vacuum forming tank 31, the inside of the liquid collecting portion 4 is also A constant vacuum is maintained, and cracks and peeling of the concentrated sludge attached to the element 16 are prevented. In this case, the unconcentrated sludge in the sludge thickening unit 3 may be returned to the original sludge storage tank 7 or may be left in the sludge thickening unit 3 as it is.

After that, the liquid collection unit 4 and the vacuum forming tank 31 are shut off, and the concentrated sludge is peeled from the element 16 by air blow or the like and discharged to the outside of the closed tank 1 as in the conventional example, but instead of air blow, It is also possible to use a liquid such as water for blowing, and when an elastic support such as a spring is used as the element 16, the blowing can be omitted.

〔Example〕

An embodiment of the present invention will be described with reference to FIG. 1. The closed tank 1 for overconcentrating sludge and the attached valves, pipes and equipment are the same as those of the conventional example shown in FIG. But,
Conventional vacuum check valve 13, vacuum pump 14, vacuum tube 15
The following structure is used instead.

That is, the liquid pipe 3 that communicates with the liquid collecting portion 4 of the closed tank 1 is provided above the vacuum forming tank 31 that generates a vacuum pressure by lowering the water level.
2 are connected via a liquid valve 33, an outflow pipe 35 provided with an outflow valve 34 is hung below the vacuum forming tank 31, and the lower end thereof is water-sealed in a liquid tank 36 that maintains a constant water level. An atmosphere opening pipe 38 having an atmosphere opening valve 37 is connected to the upper part of the vacuum forming tank 31.

In FIG. 1, reference numeral 39 is a water level gauge for detecting a predetermined HWL in the vacuum forming tank 31.

The liquid outflow pipe 10 and the liquid valve 9 may be provided separately from the atmosphere opening pipe 38 of the vacuum forming tank 31.

〔The invention's effect〕

As described above, the overconcentrator of the present invention uses the vacuum forming tank that generates a predetermined vacuum pressure by the water level drop without using the conventional vacuum pump, and It has a very beneficial effect that it keeps a stable vacuum pressure, makes it possible to remove the thickened sludge well, can easily maintain and reduce the power cost.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention, and FIG. 2 is a vertical sectional view showing an example of a conventional overconcentrating apparatus. 1 ... Closed tank, 2 ... Partition plate, 3 ... Sludge condensing section, 4 ...
… Sludge collector, 5 …… Sludge inflow valve, 6 …… Sludge inflow pipe, 7 ・ ・ ・
Raw sludge storage tank, 8 sludge pump, 9,33 liquid valve, 10 liquid outlet pipe, 11 air inlet valve, 12
... Air inlet pipe, 13 ... Vacuum check valve, 14 ... Vacuum pump, 15 ... Vacuum pipe, 16 ... Cylinder filter element, 17,17 '... Air vent valve, 18,18' ... Air vent pipe, 19 ...... Condensed sludge discharge part, 20 ...... Condensed sludge discharge valve, 21 …… Concentrated sludge discharge pipe, 22 …… Original sludge return pipe,
23 …… Original sludge return valve, 31 …… Vacuum forming tank, 32 ……
Liquid pipe, 34 ... Outflow valve, 35 ... Outflow pipe, 36 ...
Liquid tank, 37 ... Atmosphere opening valve, 38 ... Atmosphere opening pipe, 39
...... Water level gauge.

Claims (1)

[Claims] 1. A sludge concentrating section connected to a sludge inflow pipe and a liquid collecting section are partitioned and formed in the tank, and a cylindrical filter element having one end open and the other end closed is disposed in the sludge concentrating section. , A closed tank having an open end communicating with the liquid collecting part, and an atmosphere release valve provided on the upper part, and the lower end is water-sealed at a constant water level so that the lower end can be shut off, and a predetermined vacuum pressure can be generated due to a drop in the internal water level. An over-concentrating device comprising a vacuum forming tank, wherein the liquid collecting section of the closed tank and the vacuum forming tank are connected by a liquid pipe.