JP4528166B2 - Sludge pre-concentration equipment - Google Patents

Description

  The present invention relates to a pre-concentration device for sludge installed in a preceding stage of a pressurized supply dehydrator such as sewage sludge.

  In a pressure-feed type dehydrator that supplies sludge in a pressurized state such as a rotary press or screw press to perform dehydration, a pre-concentrator is installed in the preceding stage to separate and add free water in the coagulated sludge. It is known that by increasing the sludge concentration supplied to the pressure supply dehydrator, it is possible to improve the dewaterability such as the filtration rate and moisture content. This effect is particularly great in the case of non-water-removable sludge such as digested sludge and OD sludge.

  For this reason, conventionally, as shown in Patent Document 1, a wedge wire is provided inside a tank body that is supplied in a pressurized state to concentrate the aggregated sludge, and the concentrated aggregated sludge is supplied to the press-fit dehydrator. A pre-concentration device that discharges the separation liquid to the outside from the discharge port has been proposed.

However, the pressurized agglomerated sludge easily passes through the wedge wire and enters the separation liquid side, and there is a problem that the quality of the returned water deteriorates. At that time, the coagulated sludge tends to block the wedge wire. However, since the wedge wire is inside the sealed pressure tank, it cannot be easily washed and stable continuous operation cannot be performed. It was.
Japanese Patent Laid-Open No. 10-28505

  The present invention solves the above-described conventional problems, can stably concentrate the coagulated sludge at the front stage of the pressure supply dehydrator, can suppress the aggregation sludge from moving to the separation liquid side, and filtration An object of the present invention is to provide a pre-concentration device that can prevent obstruction of the body.

The present invention made in order to solve the above-mentioned problem is that the inside of a tank body to which sludge to which a flocculant is added is supplied in a pressurized state is divided into a coagulation mixing tank and a separation liquid tank by a filter, the mixing tank with connecting aggregation sludge supply line to the pressure-fed dehydrator, the separation liquid tank side provided with a pressurizing means capable of backflow mixing flocculation tank side through the filtration body the separated liquid sludge The pre-concentration device is characterized in that the pressurizing means is a pressurizing tank or propeller capable of adjusting a differential pressure with respect to the inside of the tank body . Further, a screen made of a wedge wire can be used as the filter body.

  In the pre-concentration device of the present invention, the pressure sludge to which the flocculant is added is coagulated and mixed in the coagulation mixing tank to form a floc, and is concentrated by the filter and supplied to the pressure supply dehydrator. It is the same. However, in the present invention, there is provided a pressurizing means capable of causing the separated liquid separated by the filter body to flow back to the agglomeration and mixing tank side through the filter body, so that the discharge state of the separated liquid can be controlled by the applied pressure. It is possible to suppress the transition of the coagulated sludge to the separation liquid side as compared with the conventional apparatus in which the separation liquid discharge side is open to the atmosphere. Moreover, since this pressurization means can exhibit a backwashing function, the filter body can be prevented from being blocked.

Embodiments of the present invention will be described below.
FIG. 1 shows a first embodiment of the present invention, in which 1 is a cylindrical or prismatic tank body, and a lower agglomeration mixing tank 3 and an upper part are formed by a filter body 2 installed horizontally inside the tank body. And a separate liquid tank 4. The tank body 1 has a pressure tank structure that can withstand the pressure of the supplied pressure sludge. Although the kind of the filter body 2 is arbitrary, it is preferable to use the screen which consists of a wedge wire which is easy to backwash. A stirring shaft 5 is provided in the center of the tank body 1 so as to pass through the filter body 2, a rotating motor 6 is installed at the upper part of the tank body 1, and a stirring blade 7 is provided inside the agglomeration mixing tank 3. Is provided.

  A sludge supply port 8 is connected to the lower part of the coagulation mixing tank 3, and pressurized sludge to which the coagulant G is added after being pressurized by the pressure pump 9 is supplied. The type of the flocculant G is not particularly limited, but it is preferable to use a polymer flocculant that easily forms floc. The supplied pressurized sludge is agglomerated and mixed while being properly agitated by the agitation blade 7 inside the agglomeration and mixing tank 3 to form a floc. Then, free water is separated and concentrated by the filter body 2, and the concentrated pressurized sludge is supplied to the pressurized feed dehydrator 11 through the aggregated sludge supply line 10 provided in the upper part of the aggregation mixing tank 3. .

  In this embodiment, the press-fitting type dehydrator 11 is a rotary press, and the dewatering of the pressurized sludge proceeds while moving in an arc-shaped filtration chamber constituted by screens on both sides, and is discharged as a dehydrated cake. Since the moisture content of the pressurized sludge is reduced by 1 to 2% by the pre-concentration device of the present invention, the filtration rate of the press-fitting dehydrator 11 can be improved and the moisture content of the dewatered cake is reduced by about 1 to 3%. Can be made.

  The separation liquid tank 4 is provided with a separation liquid discharge line 20. In the conventional apparatus, the separation liquid discharge line is opened to the atmospheric pressure, but in this embodiment, a pressurizing tank 12 as a pressurizing means is provided. The pressurized tank 12 has a structure in which the inside is partitioned by a partition wall 13 and compressed air can be supplied to a chamber 14 on the inlet side by an air compressor 15. The air compressor 15 is capable of adjusting a differential pressure between the internal pressure of the tank body 1 and the internal pressure of the pressurized tank 12. It is possible to detect and control the discharge of the separation liquid accordingly.

  That is, when the concentration of concentrated sludge is low, the differential pressure between the tank body 1 and the pressurized tank 12 is increased to facilitate the discharge of the separation liquid, and when the concentration of concentrated sludge is high, the difference between the tank body 1 and the pressurized tank 12 is increased. The pressure is reduced to suppress separation liquid discharge. Thereby, the concentrated sludge having a stable concentration can be always supplied to the pressure supply type dehydrator 11.

  The pressurized tank 12 can also be used as a means for backwashing the filter body 2. That is, if the pressure on the pressurized tank 12 side is made higher than the internal pressure of the tank body 1, the separated liquid flows backward to the agglomeration and mixing tank 3 side through the filter body 2, and flocs that block the filter body 2 can be removed. it can. Therefore, it is possible to easily perform the back washing operation inside the sealed tank body 1, and a stable continuous operation that has been impossible in the past can be performed.

2 and 3 show a first embodiment of the present invention, in which a siphon tank 16 having a higher head than the separation liquid tank 4 in the tank is installed in the separation liquid discharge line 20. While the filter body 2 is not clogged, the separation liquid is stored in the siphon tank 16 as shown in FIG. 2, but when the filter body 2 is clogged, the flowmeter or pressure gauge provided in the separation liquid discharge line 20 is used. The discharge pump is stopped, and the water level in the tank body 1 is lowered as shown in FIG. As a result, the lower end 17 of the separation liquid discharge pipe is exposed from the liquid surface to form a siphon, and the separation liquid in the siphon tank 16 flows back to the agglomeration mixing tank 3 side through the filter body 2, The blocked floc can be removed. In this embodiment, it is necessary to install the lower end 17 of the separation liquid discharge pipe at a position slightly above the filter body 2.

4 and 5 show a second embodiment of the present invention, in which a siphon tank 16 having a higher head than the separation liquid tank 4 is installed in the separation liquid discharge line 20 and the filter body 2 is not blocked. As shown in FIG. 4, the separation liquid is stored in the siphon tank 16 as in the second embodiment. However, in the third embodiment, a valve 18 for releasing the internal pressure of the tank body 1 is provided, and when the filter body 2 is closed, the discharge pump is stopped and the water level in the tank body 1 is lowered. As shown in FIG. 5, the valve 18 is opened to reduce the pressure in the tank body 1. As a result, the pressure difference with the siphon tank 16 becomes larger than that in the second embodiment, and the separated water in the siphon tank 16 flows back vigorously from the lower end 17 of the separation liquid discharge pipe to backwash the filter body 2. For this reason, more reliable backwashing is possible than in the second embodiment.

FIG. 6 shows a second embodiment of the present invention, in which a propeller 19 as a kind of pressurizing means is attached to the stirring shaft 5 in the separation liquid tank 4, and a downward flow is always generated to filter the separation liquid. 2 is caused to flow backward to the agglomeration mixing tank 3 side. Also according to the fourth embodiment, the transition of the aggregated floc to the separation liquid tank 4 side is suppressed, and the filter body 2 can be backwashed. Although this backwash pressure is not so strong, the effect is great because it is performed constantly.

As described above, concentrator prior to the present invention is to pre-concentrate the conventional manner pressurized圧汚mud and supplies to the pressurized feed type dehydrator, a pressurized tank to the separation tank 4 side Or since the pressurization means which consists of propellers is provided, while being able to suppress the transfer to the separated liquid side of coagulation sludge, the filter body 2 is backwashed using a pressurization means, and the filter body 2 is obstruct | occluded. Can be prevented. For this reason, stable operation over a long period of time becomes possible.

It is sectional drawing which shows 1st Embodiment. It is sectional drawing which shows the driving | running state of a 1st reference form . It is sectional drawing which shows the backwashing state of a 1st reference form . It is sectional drawing which shows the driving | running state of a 2nd reference form . It is sectional drawing which shows the backwashing state of the 2nd reference form . It is sectional drawing which shows 2nd Embodiment.

DESCRIPTION OF SYMBOLS 1 Tank body 2 Filter body 3 Aggregation mixing tank 4 Separation liquid tank 5 Stirring shaft 6 Motor for rotation 7 Stirring blade 8 Sludge supply port 9 Pressure pump 10 Aggregation sludge supply line 11 Press-in type dehydrator 12 Pressurization tank 13 Partition 14 Entrance Side chamber 15 Air compressor 16 Siphon tank 17 Lower end 18 of separation liquid discharge pipe Valve 19 Propeller 20 Separation liquid discharge line

Claims (2)

The inside of the tank body to which the sludge to which the coagulant is added is supplied in a pressurized state is divided into a coagulation mixing tank and a separation liquid tank by a filter, and the coagulation sludge to the pressure supply type dehydrator is divided into the coagulation mixing tank. A pre-concentration apparatus for sludge provided with a pressurization means capable of connecting a supply line and allowing a separation liquid to flow backward to the coagulation mixing tank side through a filter medium on the separation liquid tank side . A pre-concentration apparatus for sludge, which is a pressurized tank or propeller capable of adjusting a differential pressure with the inside of a tank body . 2. The sludge pre-concentration apparatus according to claim 1, wherein the filter body is a screen made of a wedge wire.

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