JPS6313832Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a scum discharge device attached to a sand settling basin.

Various types of ponds are installed in sewage treatment plants, pumping stations, etc., and floating scum is generated in these ponds. This scum causes foul odors and obstructs sewage treatment, so it must be discharged outside.

Conventionally, such scum is discharged to the outside together with water in the pond, temporarily stored in a scum storage tank, and then pumped to a scum screen. Conventionally, suction air and a stirrer have been used in the storage and transfer process. These work to disperse scum with a light specific gravity into the water along with the water flow, thereby increasing the efficiency of scum discharge. However, substances with very low specific gravity, such as styrofoam pieces and rubber chips, do not mix well with the water even when stirred, and are stirred while floating, so they remain floating on the water surface of the settling basin. It is becoming. Furthermore, in the pump pits of sand settling ponds at pumping stations and sewage treatment plants, sludge that cannot be removed by screens floats to the water surface of the pump pits and rots, emitting a foul odor, resulting in unhygienic conditions inside the pump pits. ing.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a discharge device that is suitable for a settling basin and a pump pit attached to the settling basin and is efficient in discharging scum.

Based on the above objective, the present invention focused on the fact that when wastewater from a settling basin flows into the pump pit, scum collects on the wall of the pump pit due to the flow, and a funnel-shaped scum is placed at that position. By arranging the trap slightly above the lower limit level of sewage and facing downward, floating scum is efficiently collected inside the scum trap and can be discharged to the outside by a self-priming pump.

Hereinafter, the structure and operation of the present invention will be specifically explained based on an embodiment shown in the drawings.

The scum discharge device 1 of the present invention is installed in a pump pit 3 attached to a sand settling basin 2. The sand settling basin 2 is equipped with a coarse screen 5, a sand pump 6, and a fine screen 7 in this order from the upstream side in the flow direction of the wastewater 4, and communicates with the pump pit 3 on the downstream side thereof.

The pump pit 3 has a bottom surface lower than the bottom surface of the sand settling basin 2, is connected to the bottom surface of the sand settling basin 2 by a guide slope 8, and is partitioned by a partition wall 9 on the side opposite to this guide slope 8. . A main pump 10 is provided near the pump pit 3. The suction port of the main pump 10 penetrates the partition wall 9 and opens inside the pump pit 3 at a position below the lower limit level Hb of the dirty water 4.

The scum discharge device 1 of the present invention includes a funnel-shaped scum trap 11 and a self-priming pump 12 as main parts. The scum trap 11 is located at the lower limit level from the wall surface of the partition wall 9 of the pump pit 3.
It is placed slightly above Hb and facing downward. The suction port of the pump 12 is connected to the upper part of the scum trap 11 through a scum suction pipe 13, and the discharge port of the pump 12 is connected to an external scum storage tank or the like through a scum discharge pipe 14. It is now possible to bring it out.

Next, the operation of the scum discharge device 1 will be explained.

The wastewater 4 flows into the settling basin 2 from the inflow direction of the arrow. This wastewater 4 contains a large amount of sand and sludge, and the sand accumulates at the bottom of the settling basin 2 and is scraped up by the sand pump 6, and the sludge is It is removed by a mesh screen 5 and a fine mesh screen 7 downstream thereof. The residue that cannot be removed by the coarse screen 5 and the fine screen 7 flows directly into the pump pit 3. The floating residue is the second
As shown in the figure, scum 15 rises to the surface and sewage 4
Due to the flow on the guide slope 8, it is brought close to the bulkhead 9 and remains floating there.
As the water level of the waste water 4 inside the pump pit 3 rises, the floating scum 15 enters the inside of the scum catcher 11, as shown in FIG. 3, and is thereby restrained. When the water level further rises and reaches the upper limit level Ha, the main pump 10 and pump 12 are automatically started. The main pump 10 sends out the dirty water 4 inside the pump pit 3 to a predetermined location. The pump 12 also pumps the scum 15 in a floating state.
The scum is sucked in together with the sewage 4 inside the pump pit 3 through the scum suction pipe 13 and transferred to the next treatment process through the scum discharge pipe 14. In this way, the water level of the waste water 4 in the pump pit 3 gradually begins to fall and reaches the lower limit level Hb. At this point, pump 12 automatically stops. When the water level further decreases and reaches the water level H at which the main pump 10 stops, the main pump 10 automatically stops in the same manner as described above. Such liquid level detection is performed by a known liquid level detection system, and these main pumps 10
The pump 12 is controlled by a control device using the liquid level system signal as an input condition.

In the above embodiment, the bottom of the grit basin 2 is connected to the pump pit 3 by the guide slope 8, but the guide slope 8 may be a substantially vertical surface. Even in this case, when the wastewater 4 flows in from one side, the floating scum 15 is mixed with the scum.
is brought closer to the partition 9 in the same manner as when the guide slope 8 is present.

In the present invention, as wastewater flows from the settling basin into the pump pit, the water flow draws the floating scum to one wall, so as the water level of the wastewater in the pump pit rises, the suspended scum Since the scum enters the inside of the scum trap, no special means is required to scrape up the floating scum, and the scum can be efficiently discharged. Therefore, the occurrence of bad odors can be prevented, and sewage treatment can proceed efficiently without scum.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of a scum discharge device for a sand settling basin according to the present invention, and FIGS. 2 and 3 are sectional views of a pump pit. DESCRIPTION OF SYMBOLS 1... Scum discharge device for a sand settling basin, 2... Sand settling basin, 3... Pump pit, 4... Sewage, 8... Guide slope, 9... Bulkhead, 11... Scum trap, 1
2...Self-priming pump, 13...Scum discharge pipe,
14...Scum discharge pipe, 15...Scum.

Claims (1)

[Scope of utility model registration request] A pump pit lower than the bottom of the sand settling tank is formed in a connected manner on one side of the sand settling tank, and a funnel-shaped scum catcher is arranged below the wall of the pump pit slightly above the lower limit level of the liquid level, A scum discharge device for a sand settling basin, characterized in that the upper part of the scum trap is connected to a self-priming pump via a scum suction pipe.