JPS5931390B2 - wastewater treatment equipment - Google Patents

Description

[Detailed description of the invention] The present invention relates to wastewater treatment equipment.

More specifically, the present invention relates to an apparatus for separating sludge in biologically treated wastewater.

When water containing air bubbles is added to wastewater containing sludge sent from a rotating disk (Biosurf), etc., and it is ejected from the bottom of a tank (we will call it a pressurized flotation tank), sludge forms on the surface of the air bubbles. The sludge that adheres to the water surface of the tank is removed by removing it with a floss scraper, and the remaining water is sent to an adjacent tank. There is a wastewater treatment device that removes sludge by filtering it with a drum-type long-hair filter (rotary spitz).

In this device, it is necessary to remove sludge adhering to the long bristles of the filter surface by backwashing the filter surface of the rotary spitz intermittently or continuously.

During backwashing, a large amount of water is sucked in from the suction port installed near the filter surface while rotating the drum, so a large amount of wastewater is generated during backwashing, and as a result, the amount of wastewater to be treated is significantly reduced. In reality, it is difficult to suppress the amount of wastewater generated by backwashing to 15% or less of the inflow water.

The present invention was made to solve these problems, and its gist is to provide a pressurized flotation tank, a scraper for scraping off sludge floating on the water surface of the pressurized flotation tank, and a scraper for removing the sludge with the scraper. A second water tank into which the remaining water flows, a rotating drum type long hair filter installed in the second water tank, a backwash suction port provided near the filtering surface of the rotating drum type long hair 7 filter, and the suction port. Sludge from a pressurizing pump connected by piping, an air dissolving tank that dissolves and stores pressurized air in water, piping connecting the pressurizing pump and the air dissolving tank, a rotating disk (Biosurf), etc. The wastewater treatment apparatus includes a wastewater supply pipe that supplies wastewater contained in the pressurized flotation tank to the pressurized flotation tank, and a pressurized water supply pipe that connects the air dissolution tank and the wastewater supply pipe via a pressure reducing valve.

The drawings are diagrams showing one embodiment of the present invention.

1 is a pressurized flotation tank, 2 is a floss scraper for scraping off sludge floating on the water surface of the pressurized flotation tank, and 3 is a second water tank.

The second water tank 3 is separated from the pressurized flotation tank 1 by a partition wall 11.

4 is a rotating drum type long hair filter (rotary spitz)
, 5 is a pressure pump.

9 is a backwash suction port provided near the 40-rotating drum surface of the rotary drum type long hair filter and spanning the entire width of the drum surface;
The suction port 9 and the pressure pump 5 are connected through piping.

6 is an air dissolving tank, and 10 is a pipe connecting the pressurizing pump 5 and the air dissolving tank 6.

Reference numeral 7 denotes a wastewater supply pipe that supplies wastewater containing sludge from a rotating disk (Biosurf), etc. to the pressurized flotation tank 1, one end of which protrudes into the lower part of the pressurized flotation tank 1, and is used to spout multiple wastewaters. A nozzle 12 is provided.

8 is a pressurized water supply pipe for supplying pressurized water containing a large amount of air from the air dissolving tank 6 to the waste water supply pipe 7, and 13 is a pressure reducing valve.

14 is an air compressor, 15 is a compressed air supply pipe for supplying compressed air to water, 16 is a floss tank, 17 is a sludge pump, and 18 is a pipe for sending sludge to dewatering equipment.

Further, 19 is a discharge pipe for discharging the treated water obtained by filtering with the rotary drum type long-hair filter 4.

Next, the action will be explained.

Immediately before the wastewater from the rotating disk (Biosurf), etc. flows into the pressurized flotation tank 1 through the wastewater supply pipe 7, the water containing a large amount of air is sent from the pressurized water supply pipe 8 via the pressure reducing valve 13. join with.

This water has a larger amount of air dissolved in it under pressure than can be dissolved under normal pressure.
When the waste water passes through the pressure reducing valve 13 and joins with the waste water, a large amount of bubbles are generated as the pressure decreases.

Therefore, waste water is ejected from the waste water ejecting nozzle 12 together with a large amount of bubbles.

Sludge in the wastewater adheres to the surface of the bubbles, floats up to the water surface in the pressurized flotation tank 1, and is scraped off by the floss scraper 2.

The scraped sludge is collected in a floss tank 16 and sent by a sludge pump 17 to a dewatering facility via piping 18.

On the other hand, the wastewater after removing the sludge floated in the pressurized flotation tank 1 overflows the partition wall 11 and flows into the second water tank 3.
The filtered treated water is filtered by the rotary drum type long hair filter 4, and is discharged from the discharge pipe 19 through the rotary shaft (hollow) of the drum of the rotary drum type long hair filter 4.

When backwashing the filtration surface of the rotary drum type long hair filter 4, the pressurizing pump 5 is operated to rotate the drum and remove the washing water and the sludge attached to the long hairs of the filtration surface from the suction port. 9, and the pressurized pump 5 supplies washing water to the pipe 10.
The air is fed to the air dissolving tank 6 under pressure.

At this time, compressed air obtained by the air compressor 14 is injected into the washing water in the pipe 10, and the air is dissolved in the water in the air dissolving tank 6.

The pressurized water containing a large amount of air obtained in the air dissolution tank 6 is
As mentioned above, it passes through the pressurized water supply pipe 8 and the pressure reducing valve 13 and joins with the waste water.

The amount of water used for backwashing the rotary drum type long-hair filter 4 is usually about 25 to 40% (for example, about 1/3) of the wastewater sent to the device.

With the device of the present invention, a sufficient amount of washing water can be used for backwashing a rotary drum type long-hair filter, and since the washing water is reused as pressurized water containing a large amount of air, there is no waste in water usage. It has the advantage of avoiding an increase in the amount of wastewater to be treated.

[Brief explanation of the drawing]

The drawing is a schematic sectional view of one embodiment of the wastewater treatment device according to the present invention. 1... Pressurized flotation tank, 2... Scraper, 3... Second water tank, 4... Rotating drum type long hair filter, 5... ...pressure pump, 6...
...Air dissolution tank, 7...Wastewater supply pipe, 8...
... Pressurized water supply pipe, 9 ... Backwash suction port, 1
0... Piping connecting the pressurizing pump and the air dissolving tank, 13... Pressure reducing valve.

Claims (1)

[Claims] 1 A pressurized flotation layer, a scraper that scrapes the sludge floating on the water surface of the pressurized flotation tank, a second water tank into which the water after removing the sludge with the scraper flows, and a rotating mechanism provided in the second water tank. A drum-type long-hair filter, a backwash suction port provided near the filter surface of the rotating drum-type long-hair filter, a pressure pump connected to the suction port via piping, and a pressurized air dissolved in water. an air dissolving tank for storing, piping connecting the pressurizing pump and the air dissolving tank, a wastewater supply pipe supplying wastewater containing sludge to the pressurized flotation tank, and the air dissolving tank and the wastewater supply pipe. a pressurized water supply pipe connecting the two via a pressure reducing valve;
A wastewater treatment device comprising: