JPS646955Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

This invention relates to a supernatant liquid discharge device with a scum removal device that is applied to a batch-type activated sludge treatment device that processes wastewater by repeating a cycle of aeration, precipitation, and discharge in a single treatment tank. The present invention relates to a supernatant liquid discharge device with a scum removal device that automatically discharges scum by pushing a float having a scum discharge port below the liquid surface at an appropriate water level in a processing tank.

[Conventional technology]

Generally, in batch type activated sludge treatment equipment,
After the sludge precipitation step in a single treatment tank, the supernatant liquid is discharged, and if scum is floating in the treatment tank at the time of discharge, it is necessary to also remove the scum. Therefore, even in the batch type activated sludge treatment apparatus, it is necessary to provide a supernatant liquid discharge device and some kind of scum removal means, as in the case of a general sludge treatment apparatus. In general sludge treatment equipment, the water level in the tank is approximately constant or only slightly fluctuates, so scum removal methods include a fixed skimmer combined with a buttful, or a floating skimmer on the liquid surface with a small water area. Floating skimmers and the like are being used with some success.

[Problem that the invention attempts to solve]

However, in the case of batch-type activated sludge treatment equipment, the water level in the tank can fluctuate by as much as 2m to 3m, so it would be difficult to simply repurpose a skimmer intended for general sludge treatment equipment, where water level fluctuations are extremely small. There was a problem in that effective scum collection could not be expected at all. For this reason, batch-type activated sludge treatment equipment should also be equipped with an optimal supernatant liquid discharge device and scum removal means, and although various improvements have been made to the supernatant liquid discharge device, the scum removal means have not been improved. As with the supernatant liquid discharge device, this is a very complicated mechanism, and there are many problems in terms of space and cost, and furthermore, automation would be extremely expensive, so it is not considered much at present. There was a problem. This idea was made to solve the above problems, and it is possible to efficiently discharge scum by using a float with a scum discharge port provided in a decanter for discharging supernatant liquid. I can do it,
Although it has a mechanically simple configuration, it can reliably collect and discharge scum generated on the liquid surface in a wide tank even if the water level in the tank fluctuates greatly.
Moreover, the collection and discharge can be automated, and
It is an object of the present invention to provide a supernatant fluid discharge device with a scum removal device that does not cause problems in terms of cost.

[Means to solve the problem]

The supernatant liquid discharge device with a scum removal device according to this invention includes a shaft pipe that is rotatably supported in the axial direction and extends laterally in a treatment tank that receives inflow sewage and performs activated sludge treatment, and An overflow pipe connected to the pipe via a discharge pipe in a direction perpendicular to the pipe and provided with a supernatant liquid overflow port that communicates with the inside of the shaft pipe through the inside of the discharge pipe, and this overflow pipe is swung up and down. A decanter for discharging supernatant overflow is constructed by a rotating means for rotating the shaft pipe in the direction, and a scum discharge port is opened in this decanter via a vertically swingable support arm. A scum discharge path is connected to the float for draining the scum that has flowed into the scum discharge port out of the system, and the overflow pipe is removably engaged with the support arm. The scum outlet is equipped with a stopper that engages the support arm at a predetermined water level in the tank, and the engagement restricts the swinging of the support arm and pushes the scum discharge port below the liquid surface. This is what I did.

[Effect]

The supernatant liquid discharge device with a scum removal device in this invention rotates the shaft pipe and lowers the decanter above the liquid level in the processing tank when discharging the supernatant liquid after the aeration and precipitation steps in the processing tank. Then, the supernatant liquid overflow port of the overflow pipe of the decanter becomes submerged, and the supernatant liquid flows in from the supernatant liquid overflow port, and the supernatant liquid flows down the discharge pipe and enters the shaft pipe. is discharged from the system through. At this time, the float with the scum discharge port formed therein is maintained in a normal floating state on the liquid level. Then, by discharging the supernatant liquid as described above,
When the water level in the treatment tank gradually decreases and the decanter follows the liquid level and descends to a predetermined position, the stopper engages with the support arm and forcibly pushes the support arm down. A float for scum discharge is pushed down below the liquid surface. As a result, scum flows in from the scum discharge port of the float, and is discharged out of the system through the scum discharge path. As a result, the above-mentioned scum is automatically discharged and collected.

【Example】

An embodiment of this invention will be described below based on the drawings. The supernatant liquid discharge device with a scum removal device of this invention is installed in a treatment tank 1 (see Figure 1) that performs activated sludge treatment of inflow sewage by repeating the cycle of aeration process, sedimentation process, and discharge process. It consists of a decanter 2 for discharging supernatant liquid and a float 3 for discharging scum. The decanter 2 includes a shaft pipe 5 (see FIG. 2) that is rotatably supported in the axial direction on the bottom side of the processing tank 1 and extends laterally, and a shaft pipe 5 that is connected to the shaft pipe 5 and extends in the right angle direction. It consists of a plurality of extending supernatant discharge pipes 6 and an overflow pipe 7 for discharging the supernatant fluid connected to span the free ends of these supernatant discharge pipes 6. More specifically, the shaft pipe 5 is adapted to be rotated in a direction to swing the skim discharge pipe 6 up and down by a rotation means 8 that is automatic, hydraulic, motor, or the like. Further, inside the shaft pipe 5, a supernatant liquid discharge passage 5b and a scum discharge passage 5b are partitioned by a blind plate 11. Supernatant liquid discharge path 5a of such a shaft pipe 5
The discharge pipe 6 is connected to the supernatant discharge pipe 6, and the overflow pipe 7 is connected to the supernatant discharge passage 5 through the supernatant discharge pipe 6.
It is connected to a. Further, a scum discharge pipe 6a is connected to the scum discharge path 5b of the shaft pipe 5, and the free end of the scum discharge pipe 6a is connected to the overflow pipe 7 as in the case of the skim discharge pipe 6. However, it is not communicated with the inside of this overflow pipe 7 by a blind plate 11. The overflow pipe 7 connected to each free end of the supernatant discharge pipe 6 and the scum discharge pipe 6a has a supernatant fluid overflow port 7a through which the supernatant fluid in the processing tank 1 flows. An opening is formed. In the decanter 2 for discharging supernatant fluid constructed in this manner, the float 3 for discharging scum is connected and supported at both ends of the overflow pipe 7 via vertically swingable support arms 9. has been done. The illustrated float 3 has a structure in which a pair of parallel float members are integrally connected at both ends, and the float member on the side far from the decanter 2 is smaller than the float member on the side closer to the decanter 2. A scum discharge port 3a is formed between these float members to allow the scum floating near the liquid level in the processing tank 1 to flow therein. This scum discharge port 3a is connected to the scum discharge pipe 6a by a scum discharge pipe 10 made of a flexible hose suitable for vertically swinging the float 3. The scum flowing in is discharged out of the system through the scum discharge pipe 6a and the scum discharge path 5b. In this related structure of the decanter 2 for supernatant liquid discharge and the float 3 for scum discharge, the float 3 is connected to both ends of the overflow pipe 7 of the decanter 2 via the support arm 9. A stopper 4 is provided to restrict the swing range of the. That is, the stopper 4 is removably engaged with the upper end of the support arm 9 at a predetermined lowering position of the overflow pipe 7, which is held near the liquid level in the processing tank 1 according to fluctuations in the water level. This engagement has the function of pushing the scum discharge float 3 below the liquid level in the processing tank 1 by restricting the upward movement of the support arm 9, and the overflow pipe 7. It has a function of releasing the engagement with the support arm 9 and returning the float 3 to its normal floating state on the liquid level when it rises from the lowered position. Here, as described above, the float 3 for discharging scum has a smaller float member on the side farther from the decanter 2, so that when the float 3 is pushed down by the stopper 4 via the support arm 9,
The small float member side sinks below the liquid surface, so that scum floating near the liquid surface flows in from the scum discharge port 3a. In FIG. 1, reference numeral 12 is a scum prevention plate installed on the decanter 2 as necessary to prevent scum from flowing into the supernatant overflow port 7a from the back of the decanter 2. do. Next, the operation will be explained. In the treatment tank 1, activated sludge treatment of the inflowing sewage is performed, with the aeration process, the settling process, and the discharge process of discharging the supernatant liquid from the decanter 2 as one cycle. Incidentally, the settled sludge in the treatment tank 1 is drawn out at an appropriate time. In such an activated sludge treatment apparatus, in the discharge step, the shaft pipe 5 is rotated by the rotation means 8, so that the decanter 2 is moved to the use position shown in FIGS. 3a and 3b (for example, inside the treatment tank 1). The supernatant liquid overflow port 7a of the overflow pipe 7 is submerged near the liquid level in the treatment tank 1, and the supernatant liquid overflow port 7a flows up into the overflow pipe 7 from this supernatant liquid overflow port 7a. Clear liquid flows in. The supernatant liquid that has flowed into the overflow pipe 7 flows down the supernatant discharge pipe 6 and is discharged to the outside through the supernatant liquid discharge passage 5a in the shaft pipe 5. At this point, Figure 3 a,
As shown in FIG. 3B, the stopper 4 is held at a position apart from above the support arm 9, and therefore the float 3 for discharging scum is held in a normal floating state on the liquid level. From this state, the water level in the treatment tank 1 gradually decreases due to the discharge of the supernatant as described above, and the decanter 2 descends following the liquid level, causing the decanter 2 to move up and down. When the movement reaches a position slightly before the lower limit position, the stopper 4 engages with the upper edge of the support arm 9, as shown in FIG. 3c, and forces the support arm 9 down. As a result, the scum discharge port 3a of the float 3 sinks below the liquid level, scum flows in from the scum discharge port 3a, and the scum sequentially flows down the scum discharge pipe 10 and the scum discharge pipe 6a, and flows down the shaft pipe. The scum is discharged to the outside through the scum discharge path 5b in the scum 5. At this time, if the lower limit position of the scum discharge port 3a is set lower than the lower limit position of the supernatant overflow port 7a of the decanter 2, the scum can be discharged more reliably. It is not necessary to discharge the scum as described above every time, and the stopper 4 may be engaged with the support arm 9 so that the stopper 4 pushes down the support arm 9 only when necessary. This operation may be performed manually or automatically using a timer or the like. Alternatively, scum on the liquid surface may be optically detected and the stopper 4 may be turned on or off based on this detection signal. Here, the above stopper 4
ON means that the stopper 4 engages with the support arm 9 and pushes the support arm 9 down, thereby pushing the scum discharge port 3a of the float 3 below the liquid surface via the support arm 9, and the scum This means that scum is discharged from the discharge port 3a. Also, the above stopper 4
OFF means that the stopper 4 is separated from the engagement position with the support arm 9 to maintain the float 3 in a normal floating state on the liquid surface, and in this floating state on the liquid surface, scum is not discharged. do not have. The stopper 4 may be turned off by automatically or manually sliding the stopper 4 itself toward the center of the overflow pipe 7. FIG. 4 shows another embodiment of the stopper 4, in which the stopper 4 is provided with an elongated hole 4a, and the support arm 9 is provided with a protrusion 9a projecting from the elongated hole 9a.
By slidably engaging the scum discharge float 3 in the same manner as described above, the scum discharge float 3 is pushed down.

[Effect of the idea]

As described above, according to this invention, the overflow pipe of the decanter that swings up and down in the processing tank supports a float for discharging scum via a support arm that can swing up and down, and this float has a scum discharge port. Although it has a simple structure in which the overflow pipe is provided with a stopper that can be connected to and detached from the support arm, the stopper opens the support arm when the water level in the treatment tank drops to a predetermined water level. The scum discharge port of the float for scum discharge is pushed down below the liquid level via this support arm, and scum flows smoothly into the scum discharge port. do. The inflowing scum is discharged out of the system through the scum discharge path, thereby automatically and efficiently discharging and recovering the scum. Therefore, in this invention, the scum can be automatically and efficiently discharged and collected by using the scum discharge port of the float for scum discharge disposed in the decanter for discharging the supernatant liquid. The configuration is extremely simple, and even if the water level in the treatment tank fluctuates greatly, the supernatant liquid and scum can be reliably separated and automatically and efficiently collected and discharged regardless of the fluctuations, saving space and space. There is no cost problem, and there is an effect that a supernatant liquid discharge device with a scum removal device suitable for a single-tank batch type activated sludge treatment device can be provided.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view of essential parts of a supernatant liquid discharge device with a scum removal device according to an embodiment of this invention, Fig. 2 is a plan view of the same, Fig. 3 is an explanatory diagram of the scum discharging process, and Fig. 4 is a FIG. 7 is a perspective view showing another embodiment of the stopper. In the figure, 1 is a processing tank, 2 is a decanter, 3 is a float for scum discharge, 3a is a scum discharge port,
4 is a stopper, 5 is a shaft pipe, 6 is a supernatant discharge pipe, 7 is an overflow pipe, 7a is a supernatant overflow port, and 8 is a rotating means.

Claims (1)

[Scope of utility model registration request] A shaft pipe that is rotatably supported in the axial direction and extends laterally in a treatment tank that receives inflow sewage and performs activated sludge treatment, and a shaft pipe that is connected to the shaft pipe through a discharge pipe that is perpendicular to the shaft pipe, an overflow pipe provided with a supernatant liquid overflow port that communicates with the inside of the shaft pipe through the inside of the pipe; and a rotating means for rotating the shaft pipe in a direction to vertically swing the overflow pipe. a decanter for discharging supernatant overflow, which is supported by the overflow pipe of the decanter via a vertically swingable support arm, and has a scum discharge port formed therein; A scum discharge path connected to the float and for draining the scum that has flowed into the scum discharge port out of the system; and a scum discharge path connected to the overflow pipe and capable of being connected to and detached from the support arm at a predetermined water level in the treatment tank. A supernatant liquid discharge device with a scum removal device, comprising a stopper that engages with the stopper and, through the engagement, restricts the swinging of the support arm and pushes the scum discharge port of the float below the liquid surface.