JPS64112B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a pressure flotation type wastewater treatment device, and particularly to a pressure flotation type wastewater treatment device in which the amount of pressurized water supplied is increased or decreased in accordance with the increase or decrease in the flow rate of raw water to be treated. Regarding equipment.

[Prior Art] Fig. 1 is an overall system diagram of a pressurized flotation type wastewater treatment apparatus.

10 is a flotation separation tank, to the bottom of which a raw water introduction pipe 12 and a settled solid content extraction pipe 14 are connected.
A portion of the treated water in the treated water tank 16 can be introduced into the raw water introduction pipe 12 via a pressurized water production device 18 and a supply pipe 20.

The solid content in the raw water introduced into the flotation separation tank 10 is floated to the surface of the liquid by the generated air bubbles, separated, and discharged through the pipe 22. Note that some of the solid content in the raw water settles and is discharged through the pipe 14. The treated water in the flotation separation tank 10 is sent to the treated water tank 16 via the waste pipe 24.

However, in such conventional pressurized flotation type wastewater treatment equipment, the amount of pressurized water is always operated to match the maximum amount of raw water to be treated, so when the amount of raw water supplied is low, the amount of pressurized water is The amount of water supplied was excessive, resulting in wasted power costs for the pressurized water supply system.

[Object of the Invention] An object of the present invention is to solve the problems of the above-mentioned prior art and to provide a pressurized flotation type wastewater treatment apparatus that can adjust the amount of pressurized water according to the flow rate of raw water to be treated.

[Configuration of the Invention] The pressurized flotation type wastewater treatment apparatus of the present invention includes a flotation separation tank, a raw water supply system and a treated water discharge system connected to the flotation separation tank, and a part of the treated water from the treated water discharge system. In equipment equipped with a pressurized water supply system that extracts pressurized water and supplies it to the raw water supply system, the amount of pressurized water supplied can be increased or decreased by increasing or decreasing the number or changing the position of valves that open and close according to increases or decreases in the amount of raw water supplied. This means that there is a means to do so.

[Embodiments of the Invention] Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a system diagram of a pressurized flotation type wastewater treatment apparatus according to an embodiment of the present invention.

10 is a flotation separation tank; scum waste pipe 22;
A settled sludge extraction pipe 14 is provided. 30 is a raw water supply system that supplies raw water to the pressurized flotation tank 10;
Raw water tank 31, raw water pump 32, flow meter 33, valve 3
4 and a pipe 35 connecting these to the bottom of the flotation tank 10. Further, 40 is a treated water discharge system, which includes a treated water tank 42 and a pressurized flotation tank 10.
A pipe 41 connecting the treated water tank 42 and the treated water tank 4
A pipe 43 is provided for sending the treated water from 2 to the discharge system.

Next, the pressurized water supply system will be explained. 50 is a circulation system that connects the treated water tank 42 and the raw water supply system. The treated water in the treated water tank 42 passes through three pipes 51a, 52a, and 53a, and is sent to the pressure pump 6.
1, 62, and 63, they merge, and compressed air is supplied from the compressor 54. Next, piping 51 provided with ejectors 71, 72, 73
b, 52b, and 53b. Each branch pipe is provided with on-off valves 81, 82, and 83. The air returned from the gas-liquid separation tank 55 is transferred to this ejector 7.
1, 72, 73, the gas-liquid separation tank 55
will be introduced to 56 is a level detector in the gas-liquid separation tank 55. The pressurized air separated in the gas-liquid separation tank 55 passes through the pipe 57 to the ejectors 71, 72,
Returned to 73. The pipe 57 is branched into three ends and connected to the ejector.

The pressurized water from which undissolved gas has been separated in the gas-liquid separation tank 55 is supplied to the pipe 35 through branch pipes 51c, 52c, and 53c provided with on-off valves 91, 92, and 93.

In response to the increase or decrease in the amount of raw water supplied, pump 6
1, 62, 63, valve 81, 82, 83, 91, 9
The controller 10 starts, stops, or opens/closes 2 and 93.
This is done by 0. That is, when the raw water supply amount detected by the flow meter 33 is about 1/3 or less of the maximum supply amount, any one of the pumps 61 to 63
is started, one of valves 81-83, valves 91-
One of the 93 is open. If the raw water supply amount is about 1/3 to 2/3 of the maximum supply amount,
Any two pumps 61 to 63, two valves 81
~83, two valves 91 to 93 are activated or opened, and when the raw water supply amount is 2/3 or more, all pumps 61 to 63 are activated, and all valves 81 to 8 are activated or opened.
3, 91 to 93 is open, and even if the raw water supply amount fluctuates, it is always kept at a predetermined ratio (for example, 30 to 93) to the raw water supply amount.
50%) pressurized water is supplied.

In addition, the valves 91 to 93 are arranged so that when the raw water supply amount is small, the valve 93 closer to the pressurized flotation tank layer 10 is opened, and as the raw water supply amount increases, the valves located further away from the pressurized flotation tank layer 10 are opened. , i.e. valve 92,
The valves 91 are opened in this order. Conversely, when the amount of raw water supplied decreases, the valve 91 is closed. By doing this, the pipe 35
The residence time inside the pump can be kept almost constant, and the predetermined stirring and mixing time of pressurized water and raw water can be maintained, and when the supply amount is low, the residence time becomes long and fine bubbles come together to form large bubbles. can be prevented. Note that when the amount of raw water supplied is about 1/3, it is only from the valve 93, when it is about 2/3, it is only from the valve 92, and when the amount of raw water is at the maximum supply, it is only from the valve 91.
The position may be changed so that pressurized water is supplied only from the

In this embodiment, branch passages 51 to 53, pressurizing pumps 61 to 63, ejectors 71 to 73, and valves 81 to 8
Although 3, 91 to 93 are all provided in parallel, the number can be any number greater than or equal to 2. Further, although the flow meter 33 is used to detect the raw water supply amount, if a plurality of raw water pumps 32 are installed in parallel, the raw water supply amount may be determined by the number of activated raw water pumps.

The controller 100 is not particularly limited, and various types of controllers may be used. For example, if a differential pressure type flow meter is used, this differential pressure is converted into the strength of an electrical signal, and the number of pressurizing pumps to be activated and the number of valves to be opened are selected based on this. I can do it. If a rotary vane type flowmeter is used, the rotation speed is detected as electrical pulses, the pulses are counted within a predetermined period of time, and the average flow rate is determined.Based on this, the number of pumps to be started and the valves to be opened are determined. You can also choose the number of When raw water pumps are installed in parallel, the pressurizing pumps to be driven and the valves to be opened can be selected in accordance with the number of raw water pumps to be driven. Of course, by combining various other known flow rate detection means and control means such as an electromagnetic flowmeter and an ultrasonic flowmeter, a control means that achieves the object of the present invention can be constructed.

[Effects of the Invention] As detailed above, the pressurized flotation type wastewater treatment device of the present invention controls the pressurized water supply amount in response to increases and decreases in the raw water supply amount, so that the pressurized water supply amount can be adjusted to an appropriate level. Therefore, it is possible to reduce the power cost for producing pressurized water.

[Brief explanation of drawings]

FIG. 1 is a system diagram of a conventional pressure levitation device, and FIG. 2 is a system diagram of a pressure levitation device according to an embodiment of the present invention. 10...Flotation separation tank, 30...Raw water supply system,
40... Treated water discharge system, 50... Circulation system, 5
5... Gas-liquid separation tank, 61-63... Pressure pump,
71-73...Ejector, 91-93...Opening/closing valve, 100...Controller.

Claims (1)

[Claims] 1. A flotation tank, a raw water supply system that supplies raw water to the flotation tank, a discharge system that discharges treated water from the flotation tank, and a raw water supply system that supplies a portion of the treated water from the discharge system. A pressurized water supply system consisting of a circulation system that returns to A pressurized flotation system comprising: a pressurized water supply amount by increasing or decreasing the number or changing the position of the on-off valves that are opened according to an increase or decrease in the amount of raw water supplied to the flotation tank; Wastewater treatment equipment.