JPH0839089A - Purifying tank and operation thereof - Google Patents

Abstract

PURPOSE:To efficiently perform aeration and filtering while uniformizing the load applied to a biological reaction tank. CONSTITUTION:When a membrane separator is operated at a point of time when a sensor detects the lowest water level (L. W. L.), the operation of the membrane separator is stopped and, at the same time, the transfer of waste water from a flow rate adjusting tank to a biological reaction tank and the operation of an aerator are started. When the sensor detects the highest water level (H. W. L.), the transfer of waste water from the flow rate adjusting tank to the biological reaction tank is cut off. When a predetermined time is elapsed, the operation of the aerator is stopped and, after the aerator is allowed to stand for a predetermined time, the membrane separator is operated and a supernatant soln. low in the concn. of activated sludge is subjected to membrane separation and a transmitted soln. is discharged from purifying tank.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a septic tank for biologically treating domestic waste water, industrial waste water and the like, and a method of operating the same.

[0002]

2. Description of the Related Art As a method for operating a septic tank for biologically treating household wastewater such as toilets, washrooms, baths and kitchens, industrial wastewater, etc., JP-A-1-151995 and JP-A-4-108600 are disclosed. The method disclosed in US Pat.

The operating method disclosed in Japanese Patent Laid-Open No. 1-151995 is such that waste water (drainage) to an aeration tank for carrying out a biological reaction.
The aerator is operated with the inflow and outflow of the water being cut off to perform aerobic treatment, and then the sludge is allowed to settle by allowing it to settle, the supernatant is transferred to the supernatant liquid tank, and the liquid in this supernatant liquid tank is transferred to a membrane. Solid-liquid separation is performed by a separation device.

The operating method disclosed in Japanese Unexamined Patent Publication No. 4-108600 discloses simultaneous aeration and filtration from the highest water level (HWL) to the lowest water level (LWL) in the biological reaction chamber into which wastewater continuously flows. The aerobic treatment is performed, and conversely, the anaerobic treatment without aeration or filtration is performed from the lowest water level (LWL) to the highest water level (HWL).

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the operating method disclosed in Japanese Patent Publication No. 5, since the supernatant liquid tank is provided separately from the biological reaction chamber (aeration tank), the entire septic tank becomes large. Moreover, although the inflow of wastewater into the biological reaction chamber is performed intermittently, the aerobic treatment and the anaerobic treatment cannot be balanced because the inflow amount is not adjusted. Furthermore, blocking the inflow of wastewater into the bioreaction chamber during aeration inevitably causes the inflow of wastewater during non-aeration, and oxygen is introduced along with this inflow of wastewater, so anaerobic The processing efficiency becomes poor.

On the other hand, even in the operating method disclosed in Japanese Patent Laid-Open No. 4-108600, anaerobic treatment is carried out from the lowest water level (LWL) to the highest water level (HWL). In this prior art example, since the wastewater constantly flows into the biological reaction chamber, the anaerobic treatment cannot be performed efficiently. In addition, the inflow of wastewater into the bioreaction chamber is continuously performed, but this amount has a peak even in one day, and the inflow amount is not constant. Therefore, the anaerobic treatment and the aerobic treatment cannot be alternately performed with good balance.

[0007]

In order to solve the above-mentioned problems, a septic tank according to the present invention has a biological reaction chamber in which an aeration device is arranged, and a flow rate for adjusting the amount of waste water flowing into this biological reaction chamber. In a septic tank provided with an adjusting part and a membrane separation device for separating waste water in the bioreaction chamber into a permeate and a retentate, the septic tank is the lowest water level (LW
L.) and a water level detecting means for detecting the maximum water level (HWL) and a control part, and the control part receives a signal from the water level detecting means and supplies waste water from the flow rate adjusting part into the biological reaction chamber. A determination means for determining whether or not the aeration means in the biological reaction chamber needs to be operated in response to a signal from the water level detection means And a timer for setting the operation and stop of the aeration device for a predetermined time, and stopping the aeration operation and activating the filtration operation after the elapse of the predetermined time.

Here, it is preferable that the filtration operation is stopped by prioritizing the signal of the lowest water level (LWL) from the water level detecting means.

Further, in the purification method according to the present invention, the biological reaction chamber in which the aeration device is arranged, the flow rate adjusting unit for adjusting the amount of waste water flowing into the biological reaction chamber, and the waste water in the biological reaction chamber When operating a septic tank equipped with a membrane separation device that separates into a permeate and a retentate, the transfer of wastewater from the flow rate control unit to the biological reaction chamber is performed when the water level in the biological reaction chamber reaches the minimum water level (LWL). Start with the highest water level (
HWL), the operation of the aeration device is performed intermittently, and the operation of the membrane separation device is performed when the operation of the aeration device is stopped and after a lapse of a predetermined time after the operation of the aeration device is stopped.

The operation of the aeration device and the operation of the membrane separation device are each performed 1 time from the start of transfer of waste water from the flow rate adjusting unit to the biological reaction chamber to the start of next transfer.
It is carried out in turn, when starting the transfer of waste water from the flow rate adjusting unit to the biological reaction chamber, and when starting the operation of the aeration device,
It is preferable that the operation of the membrane separation device is stopped at the same time as the operation is automated because the control is simple.

[0011]

[Function] The peak inflow of wastewater within one day is ensured by the flow rate adjusting unit to make the load applied to the biological reaction chamber uniform, and aeration and filtration are efficiently performed under this condition.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a cross-sectional view of a septic tank according to the present invention. The septic tank 1 has a flow rate adjusting section S1 and a biological reaction chamber S2 defined by a partition wall 2, and the flow rate adjusting section S1 has a wastewater introduction pipe. 3, high water level (HWL) and low water level (LW)
The water level sensor 4 for detecting L.) is provided, and when the water level sensor 4 detects the highest water level (HWL) or the lowest water level (LWL), the operation of the septic tank 1 is stopped or an alarm is issued.

A pump 5 and a pipe 6 for transferring wastewater from the flow rate adjusting unit S1 to the biological reaction chamber S2 are provided between the flow rate adjusting unit S1 and the biological reaction chamber S2. In addition, pump 5
It is also possible to use an air lifter or the like instead of using.

On the other hand, in the biological reaction chamber S2, a membrane separation device 7
And the aeration device 12 is arranged below the membrane separation device 7. Here, the membrane separation device 7 includes a separation membrane 8 such as a hollow fiber membrane, a water collection pipe 9, a pipe 10 and a pump 11.
The separation membrane 8 may be a tubular membrane or a flat membrane. Further, the separation membrane 8 may be provided outside as a membrane module without being immersed in the biological reaction chamber S2.

Further, the biological reaction chamber S2 is provided with a water level sensor 13 for detecting the maximum water level (HWL) and the minimum water level (LWL) of the wastewater, and a signal from this water level sensor 13 causes the biological reaction chamber S2 to flow from the flow control unit S1. The pump 5 for transferring the waste water to the pump, the pump 11 of the membrane separation device 7, and the blower 14 of the aeration device 12 are turned on and off.

That is, the control section to which the signal from the water level sensor 13 is inputted receives the signal from the water level sensor 13 and supplies the waste water from the flow rate adjusting section S1 into the biological reaction chamber S2. A pump operation necessity determination unit that determines whether or not, an aeration device operation necessity determination unit that receives a signal from the water level sensor 13 and determines whether or not the operation of the aeration device 12 in the biological reaction chamber S2 is necessary, and an aeration device. The timer includes a timer for setting the operation and the stop for a predetermined time, stopping the aeration operation, and activating the filtration operation after the elapse of the predetermined time. When the water level sensor 13 detects the lowest water level (LWL), the filtration operation is immediately stopped.

Next, an example of the method for operating the septic tank according to the present invention will be described with reference to FIG. 2 showing a processing pattern. In this embodiment, one pattern is set from the start of transition of the waste water from the flow rate adjusting unit S1 to the biological reaction chamber S2 to the start of the next transition, and this is repeated. When the time when the sensor 13 detects the lowest water level (LWL) in one pattern is taken as a starting point, the membrane separation device 7 is operated at this time.
When operating the, the operation of the membrane separation device 7 is stopped,
At the same time, the transfer of waste water from the flow rate adjusting unit S1 to the biological reaction chamber S2 and the operation of the aeration device 12 are started.

In the above-mentioned state, the operation (filtration) of the membrane separation device 7 is stopped, and since the wastewater is flowing into the biological reaction chamber S2, the water level rises and eventually reaches the maximum water level (HWL). When the sensor 13 detects the maximum water level (HWL), the driving of the pump 5 is stopped, and the transfer of the waste water from the flow rate adjusting unit S1 to the biological reaction chamber S2 is cut off.

On the other hand, from the flow rate adjusting unit S1 to the biological reaction chamber S2.
The operation of the aeration device 12 is continued even after the transfer of the wastewater to the wastewater is shut off, and the aerobic treatment for nitrifying ammonia nitrogen in the wastewater is performed in the biological reaction chamber S2.

After this, when the predetermined time has passed, the operation of the aeration device 12 is stopped and the aeration device 12 is left standing for a predetermined time. Aeration device 12
After the operation is stopped, oxygen is not supplied into the biological reaction chamber S2, and therefore anaerobic treatment is performed. By this anaerobic treatment, nitrate nitrogen is gasified and denitrification proceeds.

After a lapse of a predetermined time in which the activated sludge settles in the bioreaction chamber S2 by the above-mentioned standing, the membrane separation device 7 is operated in response to a signal from the timer, and the supernatant with a low activated sludge concentration is operated. The liquid is subjected to membrane separation, and the permeated liquid is discharged from the septic tank. Then, when the sensor 13 detects the lowest water level (LWL), the operation of the membrane separation device 7 is stopped, a predetermined non-aeration time is secured, and then the transfer of waste water and the operation of the aeration device 12 are started.

In this method, the membrane separation performance is determined by the flow rate adjusting chamber S1.
If the capacity is equal to or higher than a predetermined capacity for discharging the amount of inflow into the bioreaction chamber S2 from the membrane, it is not necessary to perform quantitative membrane separation, and thus the septic tank is operated even if the performance of the membrane deteriorates due to long-term operation. There is an advantage that stable wastewater treatment performance can be maintained for a long time without affecting the pattern. Also, FIG.
When the membrane separation operation is quantitative filtration as shown in, if the filtration time is set in advance, the end of the filtration time and the arrival at the lowest water level (LWL) can always be matched, so the lowest water level Detection and its control are unnecessary, and the structure is simple.

In the embodiment, the operation of the aeration device 12 and the operation of the membrane separation device 7 are performed once in one pattern, but they may be performed multiple times.

[0024]

As described above, according to the present invention, a biological reaction chamber having an aeration device arranged therein, a flow rate adjusting section,
When operating the septic tank equipped with the membrane separation device, the load applied to the biological reaction chamber is made uniform regardless of the peak inflow into the septic tank, the aeration device is operated intermittently, and the operation of the membrane separation device is further performed. Is performed when the operation of the aeration device is stopped and after a lapse of a predetermined time after the operation of the aeration device is stopped. Therefore, all of the aerobic treatment, the anaerobic treatment, and the membrane separation treatment can be efficiently performed.

In particular, automatic operation is performed by operating the aeration device and the membrane separation device once each between the start of the transfer of waste water from the flow rate adjusting unit to the start of the transfer of the next waste water. It is easy to perform by patterning, and by operating the aeration device before the operation of the membrane separation device, anaerobic treatment is performed after aerobic treatment. Nitrification and denitrification can be performed efficiently,
The amount of untreated ammoniacal nitrogen in the treated water discharged from the septic tank can be extremely reduced.

Further, since the aeration operation and the inflow of the wastewater overlap by simultaneously making the start of the transition of the wastewater from the flow rate adjusting unit to the biological reaction chamber and the start of the operation of the aeration device, the bacterial cells and the wastewater are separated from each other. If the mixing is sufficiently performed, and quantitative filtration is further performed so that the start time and the operation time of the membrane separation device are stopped at the same time, the control is simplified and the automation is facilitated.

[Brief description of drawings]

FIG. 1 is a sectional view of a septic tank according to the present invention.

FIG. 2 is a graph showing a treatment pattern of a method for operating a septic tank according to the method of the present invention.

FIG. 3 is a graph showing a treatment pattern of a method for operating a septic tank according to another embodiment.

[Explanation of symbols]

1 ... Septic tank, 4, 13 ... Water level sensor, 5, 11 ... Pump, 7 ... Membrane separation device, 8 ... Separation membrane, 12 ... Aeration device, S
1 ... Flow rate adjusting unit, S2 ... Biological reaction chamber.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C02F 1/44 ZAB K 9538-4D 3/00 ZAB F 9/00 ZAB 501 F 502 E 503 C 504 AC (72) Inventor Urugutsu Katsushi 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu, Fukuoka Prefecture Totoki Equipment Co., Ltd. (72) Yuichi Okuno 2-1-1, Nakajima, Kokurakita-ku, Kitakyushu, Fukuoka No. Totoki Equipment Co., Ltd.

Claims (5)

[Claims] 1. A biological reaction chamber in which an aeration device is arranged, a flow rate adjusting unit for adjusting the amount of waste water flowing into the biological reaction chamber, and waste water in the biological reaction chamber is separated into a permeate and a retentate. In a septic tank equipped with a membrane separation device for performing the septic tank, the septic tank is provided with a water level detecting means for detecting a minimum water level (LWL) and a maximum water level (HWL) in the biological reaction chamber, and a control unit, and the control unit includes: Upon receiving a signal from the water level detection means, a transfer means operation necessity determination section for determining whether or not the transfer means for supplying wastewater into the biological reaction chamber from the flow rate adjustment section and a signal from the water level detection means are received. The aeration means operation necessity determination unit that determines whether or not to operate the aeration means in the biological reaction chamber and the operation or stop of the aeration device are set for a predetermined time, and the aeration operation is stopped and the filtration operation is activated after the predetermined time has elapsed. With a timer Septic tank characterized by Mukoto. 2. The septic tank according to claim 1, wherein the stop of the filtration operation is the lowest water level (LW from the water level detecting means).
A septic tank characterized in that the signal of L.) is prioritized. 3. A biological reaction chamber in which an aeration device is arranged, a flow rate adjusting unit for adjusting the amount of waste water flowing into the biological reaction chamber, and waste water in the biological reaction chamber is separated into a permeate and a retentate. In the method for operating the septic tank equipped with the membrane separation device, the transition of the wastewater from the flow rate adjusting unit to the biological reaction chamber starts from the time when the water level in the biological reaction chamber becomes the minimum water level (LWL) and the maximum water level ( HWL) until
The operation of the aeration device is performed intermittently, and further, the operation of the membrane separation device is performed when the operation of the aeration device is stopped and after a lapse of a predetermined time after the operation of the aeration device is stopped. Method. 4. The method for operating the septic tank according to claim 3, wherein the operation of the aeration device and the operation of the membrane separation device are started from the start of transition of waste water from the flow rate adjusting unit to the biological reaction chamber and then to start of next transition. The method for operating the septic tank is characterized in that each of the steps is performed once before the process. 5. The method for operating the septic tank according to claim 4, wherein the start of transfer of waste water from the flow rate adjusting unit to the biological reaction chamber, the start of operation of the aeration device, and the stop of operation of the membrane separation device. A method for operating a septic tank, which is characterized in that the time and the time are simultaneously performed.