JPH0999295A - Structure of sedimentation tank in sewage treating equipment using activated sludge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need of providing the sedimentation tank with a suspended matter collection port and to surely discharge suspended matter from the sedimentation tank by providing the inside of a sedimentation vessel of the sedimentation tank with a water surface suspended matter collector having a large number of through holes so as to be movable in the vicinity of a supernatant recovery section. SOLUTION: The sewage treating equipment is provided with a sewage inflow section 1, an aeration tank 2, a distribution section 3, a sedimentation tank 4 and a storage tank 5. The sedimentation tank 4 is provided with a sedimentation vessel 6 having a settled sludge recovery section 6a at its bottom and an overflow groove 7 (supernatant recovery section) formed through an overflow wall 7a. In the space between a water surface part sludge agitating plate 4 rotating with a rotary shaft 10 as the center and the inner peripheral surface of the sedimentation vessel 6 in the vicinity of the overflow groove 7, a water surface suspended matter collector 15 is placed on the lower side of a water surface part sludge agitation arm 13 so as to be adjacent to the sludge agitating plate 4 and also attachable and detachable. Suspended matter such as bulky scum or dust in the water surface part above settled treatment process sludge in the sludge sedimentation vessel 6 retains within the suspended matter collector 15 without passing through through holes of the collector 15. Therefore, the suspended matter is surely collected by this suspended matter collector 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a settling tank for separating and recovering settling sludge and supernatant water in a sewage treatment apparatus using activated sludge.

[0002]

2. Description of the Related Art In a conventional sewage treatment apparatus, an aeration tank for purifying the supplied sewage and a settling tank for separating the treated sludge from the aeration tank into settling sludge in a settling vessel and supernatant water in an overflow ditch. I have it.

In this settling vessel, floating substances such as scum and dust are likely to collect on the surface of the treated sludge on the water surface, and there is a possibility that these floating substances may flow out to the overflow ditch along with the supernatant water. Since the supernatant water from this overflow ditch is sterilized by chlorine and discharged into a river, it is not preferable that the suspended matter is mixed with the supernatant water.
Therefore, in the sedimentation container, there is provided a floating material recovery port for discharging the floating material carried by the water surface sludge agitating plate which rotates around the rotating shaft.

[0004]

However, in the settling vessel filled with the treated sludge, only the suspended matter carried by the water surface sludge agitation plate is surely discharged to the suspended matter recovery port, and the suspended matter is also discharged. The suspended solids recovery port must be designed so that treated sludge is not discharged from the recovery port. Therefore, the structure of the precipitation tank becomes complicated and the equipment cost rises.

An object of the present invention is to eliminate the floating material recovery port in the settling tank, which causes the above problems, and to reliably discharge the floating material.

[0006]

The present invention will be described with reference to the reference numerals in the drawings (FIGS. 1 to 5) of the following embodiments. In the sewage treatment apparatus according to the first aspect of the invention, the structure of the settling tank is configured as follows.

A settling tank (4) equipped with a settling vessel (6) having a settling sludge collecting section (6a) and a supernatant water collecting section (7).
In the vicinity of the supernatant water collecting part (7), a water floating material recovery body (15) having a large number of through holes (15a) is movably provided inside the precipitation container (6).

The second invention adds the following constitution to the first invention. The water surface floating material recovery body (15) is provided so as to be rotatable around the rotation shaft (10) along the inner peripheral surface of the precipitation container (6).

The third invention adds the following configuration to the first invention. The water surface suspended solid collecting body (15) is provided between the water surface sludge agitating plate (14) which rotates around the rotating shaft (10) and the inner peripheral surface of the precipitation vessel (6). 1
It is provided so as to be rotatable along with the inner peripheral surface of the precipitation container (6) together with 4).

Therefore, in each invention, when sludge enters the water surface floating material recovery body (15), relatively large floating materials such as scum and dust on the water surface above the sludge are collected in the water surface floating material recovery body (1).
It does not pass through the through hole (15a) of 5), but remains inside thereof, and others pass through this through hole (15a).

[0011]

DETAILED DESCRIPTION OF THE INVENTION

First Embodiment First, the structures of the wastewater treatment apparatus and the settling tank thereof according to the first embodiment of the present invention will be described with reference to FIGS.

(Outline of Sewage Treatment Apparatus and Settling Tank Structure Thereof) The sewage treatment apparatus schematically shown in FIG.
It is provided with a sewage inflow section 1, an aeration tank 2, a distribution section 3, a precipitation tank 4 and a storage tank 5.

An unspecified amount of sewage flows into the sewage inflow section 1 irregularly. The sewage is supplied from the sewage inflow section 1 to the aeration tank 2. The aeration layer 2 is purified by activated sludge (sludge inhabiting microorganisms). The treated sludge after purification is sent from the aeration layer 2 to the distribution unit 3.

In the distribution unit 3, the treated sludge is distributed into a predetermined amount of returned sludge and other excess sludge. The returned sludge returns to the wastewater inflow section 1. On the other hand, excess sludge is settling tank 4
Sent to

As shown in FIGS. 1 (b) and 2, the settling tank 4 has a settling vessel 6 having a settling sludge collecting section 6a at the bottom, and a circular overflow wall 7a at the outer periphery of the upper part of the settling vessel 6.
And an overflow groove 7 (supernatant water collecting part) provided via the. The surplus sludge from the distribution unit 3 is supplied to the central portion of the settling container 6, and is settled in the settling sludge collection unit 6a and the supernatant water flowing into the overflow ditch 7 over the overflow wall 7a. Be divided. The supernatant water sent from the overflow groove 7 to the discharge part 8 is sterilized with chlorine and discharged to a river or the like.

A shaft 10 rotated by a motor 9 is vertically inserted into a central portion of the sedimentation container 6 toward a sedimentation sludge recovery unit 6a. A bottom sludge stirring plate 12 is attached to a bottom sludge stirring arm 11 extending from the lower end of the rotary shaft 10. From the upper end of the rotary shaft 10 to the overflow wall 7a
Surface sludge agitating arm 1 extending radially toward the sea
A water surface sludge agitation plate 14 is attached to the lower side of No. 3. When the bottom sludge stirring arm 11 and the water surface sludge stirring arm 13 are rotated by the motor 9, the sludge is stirred by the bottom sludge stirring plate 12 and the water surface sludge stirring plate 14.

The settled sludge concentrated in the settling layer 4 is sent from the settled sludge collecting section 6a to a storage tank 5 where it is incinerated or used for various purposes. (Regarding the improved portion of the settling tank 4) The water surface sludge stirring plate 14 rotating around the rotating shaft 10 and the overflow groove 7
Between the inner peripheral surface of the settling vessel 4 in the vicinity (inner peripheral surface of the overflow wall 7a), the water surface suspended solid recovery body 15 is adjacent to the water surface sludge stirring plate 14 below the water surface sludge stirring arm 13. It is detachably attached.

As shown in FIG. 3A, the water surface suspended matter recovery body 15 is a bag-shaped wire mesh body and has a large number of through holes 15a. In the water floating material recovery body 15, a recovery port 16 is provided on the rotation direction A side of the water surface sludge agitating arm 13 shown in FIG. 2, and the recovery port 16 is moved in a direction B opposite to the rotation direction A. It is blocked to block the flow of water through it. Since this water surface floating material recovery body 15 has a bag shape, a floating material mounting portion 17 is formed on the bottom thereof.

In the water surface sludge agitation plate 14 shown in FIGS. 2 and 3 (b), the agitation surface 14a on the rotation direction A side.
Is inclined by an angle θ so that the radial straight line passing through the center of rotation of the rotating shaft 10 gradually approaches from the rotating shaft 10 side to the surface floating material recovery body 15 side.

A water jet outlet 18 is attached to the rotary shaft 10 to rotate therewith. The water flow direction from the jet port 18 is substantially along the water surface sludge agitating plate 14.
The present embodiment has the following features (a) to (e).

(B) When the water surface sludge agitating plate 14 rotates about the rotating shaft 10, the water surface suspended solid recovery body 15 rotates along with the water surface sludge agitating plate 14 along the inner peripheral surface of the precipitation vessel 6. To do. When the treated sludge enters the water surface floating material collector 15, the floating matters such as relatively large scum and dust on the water surface of the treated sludge are collected in the water surface floating material collector 1.
5 does not pass through the through hole 15a, but remains inside thereof, but the others pass through this through hole 15a. Therefore, the floating material recovery body 15 can reliably recover the floating material.

(B) The stirring surface 1 of the water surface sludge stirring plate 14
As described above, 4a has an inclination angle θ with respect to the radial direction. Therefore, the suspended matter that collides with the stirring surface 14a will be collected along the stirring surface 14a.
They are collected on the 5th side and collected as described in (a) above. Therefore, even if the water surface suspended solid recovery body 15 is provided only in a part near the overflow wall 7a, it is possible to reliably recover the suspended solids accumulated on the treated sludge in the entire radial direction within the settling vessel 6. .

(C) The floating material recovery body 15 is the overflow wall 7
It is provided only in a part near a. Therefore, the water surface floating material recovery body 15 can be downsized, and the water surface floating material recovery body 15
Easy to put on and take off. Therefore, it is possible to easily perform the work of discarding the suspended matter accumulated in the water surface floating material recovery body 15 or replacing the damaged water surface floating material recovery body 15.

(D) The water jet 18 can generate a water flow on the treated sludge along the water sludge agitator plate 14 toward the water surface suspended solids recovery body 15. for that reason,
The suspended matter colliding with the agitating surface 14a of the water surface sludge agitating plate 14 is collected along the agitating surface 14a toward the water surface suspended matter recovering body 15 side and is recovered as described in (a) above.
Therefore, even if the water surface suspended solid recovery body 15 is provided only in a part near the overflow wall 7a, it is possible to reliably recover the suspended solids accumulated on the treated sludge in the entire radial direction within the settling vessel 6. .

(E) Existing water surface sludge stirring arm 13
Since the water surface floating material recovery body 15 is provided by effectively utilizing
The rotating means of the water surface floating material recovery body 15 can have a simple structure.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. The second embodiment differs from the first embodiment in the following points.

In the first embodiment, a water surface sludge agitating plate 14 and a water surface suspended matter recovery body 15 are provided below the water surface sludge agitating arm 13. In the second embodiment, the water surface sludge agitation plate 14 is omitted, and instead, a water surface suspended solid recovery body 15 is provided below the water surface sludge agitation arm 13 in the entire radial direction thereof. The water jet 18 in the first embodiment is also not provided. In addition to the characteristics (a) and (e) of the first embodiment, the second embodiment can more reliably collect the suspended solids accumulated on the treated sludge in the entire radial direction inside the precipitation container 6. The floating material recovery body 15 of the second embodiment has not only the function of recovering the suspended material but also the function of stirring the treated sludge.

In addition to the above embodiments, the following configuration (a) may be adopted. (A) The floating material recovery body 15 is changed to something other than a wire mesh body, for example, a bag-shaped metal plate having a large number of through holes formed therein.

[0029]

According to the settling tank structure of the sewage treatment apparatus according to the present invention, the floating surface recovery body for water surface is recovered without using the floating material recovery port of the prior art which causes the increase of the equipment cost and the complicated structure. Due to (15), the suspended matter can be reliably collected.

[Brief description of drawings]

FIG. 1A is a schematic system diagram showing a sewage treatment apparatus according to a first embodiment, and FIG. 1B is a schematic front sectional view showing a settling tank thereof.

FIG. 2 is a schematic plan sectional view showing the settling tank of FIG. 1 (b).

3A is an enlarged cross-sectional view taken along line XX of FIG. 2, and FIG. 3B is a partially enlarged cross-sectional view taken along line YY of FIG.

FIG. 4 is a schematic plan sectional view showing a precipitation tank of a second embodiment.

5A is a schematic partial front sectional view showing a precipitation tank of a second embodiment, and FIG. 5B is a partially enlarged sectional view taken along the line ZZ of FIG.

[Explanation of symbols]

2 ... Aeration tank, 4 ... Sedimentation tank, 6 ... Sedimentation vessel, 6a ... Sedimentation sludge collection part, 7 ... Supernatant water overflow ditch (supernatant water collection part), 14 ...
Water surface sludge stirring plate, 15 ... Water surface floating material recovery body, 15a ...
Through hole.

Claims (3)

[Claims] 1. A settling tank (4) provided with a settling vessel (6) having a settling sludge collecting section (6a) and a supernatant water collecting section (7), in the vicinity of the supernatant water collecting section (7). A structure of a settling tank in a sewage treatment apparatus using activated sludge, characterized in that a water floating material recovery body (15) having a large number of through holes (15a) is movably provided inside the settling vessel (6). 2. The water surface suspended solid recovery body (15) according to claim 1 is provided so as to be rotatable around the rotation shaft (10) along the inner peripheral surface of the precipitation container (6). Of a settling tank in a sewage treatment system using activated sludge characterized by the above. 3. A water surface suspended solid recovery body (15) according to claim 1, wherein a water surface sludge agitating plate (14) rotating around a rotating shaft (10) and an inner peripheral surface of a sedimentation container (6). Between
A settling vessel (6) together with the water surface sludge stirring plate (14)
A structure of a settling tank in a sewage treatment apparatus using activated sludge, which is rotatably provided along an inner peripheral surface of the sewage treatment apparatus.