JPS63294994A - Method for operating malodor preventive device for waste water tank for building or the like - Google Patents

Abstract

PURPOSE:To efficiently prevent rotting of the sewage in a waste water tank and generation of malodors with less electric power consumption by intermittently operating an aeration device in such a manner that the dissolved oxygen or oxidation reduction potential in the tank attains a prescribed value. CONSTITUTION:The dissolved oxygen (DO) or oxidation reduction potential (ORP) of the sewage in the miscellaneous waste water tank 1 is detected by a detector 11. The operation of the aeration device 3 is stopped when the detected value attains the upper limit value set in an upper and lower limit setter 12. The operation of the aeration device 3 is restarted when the measured value attains the lower limit value. The rotting of the sewage in the miscellaneous waste water tank 1 and the generation of the malodors are prevented by intermittently operating the aeration device 3 in such a manner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a preferred method of operating an aeration device installed in a building drainage tank, a pump well at a pump station, etc. for the purpose of preventing bad odors.

[Conventional technology and its problems]

Various kinds of gray water and human waste generated within a building are usually collected by gravity in a drainage tank installed underground, and then drained to a public sewerage facility by a drainage pump. However, conventional drainage tanks for buildings are simply equipped with water tanks, and the problem often arises in that the stagnant sewage gets stale and generates a bad odor. For this reason,
Attempts have been made to install a blower and perform 111i'X to prevent anaerobic decay of wastewater, but aeration! ! Because the operating method of the equipment was not appropriate, there were problems such as not being able to obtain sufficient odor prevention effects, and even if the effects were obtained, the electricity costs were high.

The present invention aims to efficiently prevent the occurrence of bad odors by supplying air into a drainage tank and providing an appropriate operating method for an aeration device installed to mix and stir the tank. .

[Means for solving problems]

By intermittent aeration operation of the aeration device installed in the building drainage tank in conjunction with at least one of the Do meter, ORP meter, or timer, it is possible to prevent the sewage in the drainage tank from rotting and causing bad odors. Eggplant.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a gray water tank with a required volume installed in the basement of a building, and an aeration device 3 is installed at a desired position on the bottom 2 of this gray water tank. FIG. 2 is a detailed explanatory diagram of this aeration device, which is composed of a submersible motor 4, a stirring blade 5, a draft tube 6, and an air blowing pipe 7. The submersible motor 4 is fixed to the tank bottom, and is integrally provided with a draft tube 6 having an upper end 6a extending in a trumpet shape and a lower part 6b bent in an L-shape along the tank bottom.
A stirring blade 5 driven by the motor is provided inside this traft tube. An air blowing pipe 7 is provided in the draft tube 6 so that the air blowing lower a is inserted approximately at the center of rotation and within the inner diameter of the tip of the stirring blade.

The upper end of this air blowing pipe 7 is a pipe having a diameter such that it is always open to the atmosphere even if the water level fluctuates, so that the required amount of air can be blown into the waste water.

In the apparatus configured as described above, when the submersible motor 4 is driven, the stirring blades 5 rotate to stir the wastewater in the tank. This also generates negative pressure in the wastewater at the tip of this blade, and air from the atmosphere is sucked in from the air blower v7, blown into the wastewater from the air blower lower a, and mixed with the wastewater in the draft tube. , is pushed out toward the front of the draft tube.

The scum floating on the water surface is removed by the stirring blade 5.
The waste water flows into the draft tube together with the waste water, and is crushed by the stirring blade.

As described above, the aeration apparatus shown in this embodiment can not only agitate and aerate the inside of the drainage tank but also crush floating scum at the same time, but it may be an aeration apparatus that cannot crush scum. However, since scum is also one of the sources of bad odor, it is desirable to employ an aeration device with a scum crushing function or to provide a separate stirrer for scum crushing.

On the other hand, the drain pump 9 shown in FIG.
0N-OFF operation is performed in conjunction with 0, so that the water level is always between the high water level HWL and the low water level LWL. At this time, HWL and LWL are the suction port 6a of the draft tube.
If the distance from the upper end of the tank to the water surface is set to about 100 to 200 nws, floating scum on the water surface can be efficiently sucked in.

In order to intermittently operate the aeration system having the above functions, a detector 11 and an upper and lower limit setter 12 for dissolved oxygen (Do) or oxidation-reduction potential (ORP) are provided. The upper and lower limit setter 12 stops the aeration device when the measured value of dissolved oxygen or redox potential reaches the upper limit set value, and restarts the aeration device when the measured value drops to the lower limit set value. By repeating ON-OFF operation of the aeration equipment with a simple control device,
Dissolved oxygen or redox potential in the tank can be maintained within the upper and lower set values.

Most of the malodorous components generated from sewage are hydrogen sulfide, and as the sewage flows in and accumulates, the inside of the tank becomes reduced, and the activity of anaerobic microorganisms such as @ acid-reducing bacteria present in the sewage becomes active. When this occurs, proteins containing sulfate ions and sulfur in the wastewater are decomposed and a large amount of hydrogen sulfide is generated. Therefore, by maintaining wastewater in an aerobic state through appropriate aeration, it is possible to prevent the generation of bad odors such as hydrogen sulfide. however,
In order to exhibit the odor prevention effect, the dissolved oxygen must be at least 0.5 mg / or more, and the redox potential must be -100 m
It is necessary to maintain the voltage above V. As the amount of aeration increases, dissolved oxygen and oxidation-reduction potential rise, and the amount of bad odor generated decreases, but beyond a certain point, almost no bad odor is generated, so there is no need to carry out further aeration, and this is an energy-saving measure. From this point of view as well, it is preferable to stop aeration. At this time, the DO value of the sewage was about 3 mg/, and the ORP value was +50.
Since it is approximately mV, by setting the upper and lower limits near this value, it is possible to efficiently prevent bad odors with less power consumption.

Next, the aeration device with the above configuration was installed in a building drainage tank of about 15a3, and the ORP value in the tank was only ±OmV ~ +100w+
The upper and lower limits of the oxidation-reduction potential were set to be V, and intermittent aeration operation of the aeration device was performed.

The hydrogen sulfide concentration in the air inside the tank was up to 10 before the aeration equipment was installed.
ppmLu, but during the actual operating period, the concentration could be maintained at a low level of 0.01 ppm or less. In addition, since the operating time of the aeration equipment at this time was approximately 40% of that in continuous operation, it was also
An energy saving effect of 0% or more was obtained.

FIG. 3 shows another embodiment of the present invention, in which the aeration device is operated in a simple ON-OFF state using a timer 13. In this case, the set values for the operating time and stop time are determined by measuring the DO value or ORP value in each time period in advance, and as mentioned above, the dissolved oxygen at all times is 0.5 + wg/
It is necessary to set the time so that the redox potential becomes -100 mV or more. The set values may be fixed such as aeration time of 20 minutes and stop time of 40 minutes, but the aeration time and stop time can be adjusted using a 24-hour timer or bin board timer, taking into account daily inflow load fluctuations. Values may be set separately.

[Effects of the Invention] According to the present invention, Fr! While detecting at least one of dissolved oxygen and redox potential, the preset dissolved rII! By intermittent operation in which aeration is stopped at the upper limit of the element or oxidation-reduction potential and restarted at the lower limit, or by intermittent operation using a timer, the sewage in the drainage tank will rot and odor will be reduced. This can be efficiently prevented with low power consumption.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a gray water tank installed in the basement of a building, etc.
The figure is a detailed explanatory diagram of the aeration device, and FIG. 3 is a diagram of a different embodiment. 1 is a gray water tank, 2 is a tank bottom, 3 is an aeration device, 4 is a submersible motor, 5 is a stirring blade, 6 is a draft tube, and 7 is an air blowing pipe. Gma 77' 1 1st II)

Claims (3)

[Claims] (1) In order to prevent the generation of bad odors from sewage, in building drainage tanks equipped with aeration equipment, pump wells at pump stations, etc., ensure that the dissolved oxygen or oxidation-reduction potential in the tank is within the specified range. , a method for operating an odor prevention device in a building drainage tank, etc., characterized by intermittent operation of an aeration device. (2) A drainage tank for a building according to claim 1, wherein the method of intermittent aeration is to stop aeration at the upper limit of dissolved oxygen or redox potential, restart aeration at the lower limit, and repeat this process. How to operate a malodor prevention device. (3) The method for operating a malodor prevention device in a building drainage tank or the like as set forth in claim 1, wherein the intermittent aeration is performed using a timer.