JPS5898187A - Operation of aerating cell equipped with defoaming means - Google Patents

Abstract

PURPOSE:To perform the pertinent conversion of night soil into compost while temperately using bubbles for the retention of heat, by detecting the temperature or pH of the night soil to switch and operate an aerator in the order of continuous, intermittent and continuous operations, and driving a bubble breaker or a liquid-spreading defoamer according to circumstances. CONSTITUTION:In an aerating cell 1, a bubble breaker 10 is driven at a time for preparing the propagation of bacteria so that bubbles temperately remain on the liquid surface, and an aerator 2 is continuously driven to raise the temperature of the liquid 30. Hence, aerating air is inhaled through a muffler 15, an outer cylinder 11, an air-introducing pipe 9, the main body 7 of a nozzle, and the input of a motor 12 for the bubble breaker is also utilized for raising the temperature. When the condition comes to a stage for the propagation of bacteria, the temperature or pH is detected by a detector 24, and a motor 4 is switched into an intermittent operating state through a controller 27, an amplifying circuit 28 and an output circuit 29 to prevent overaeration. When the amount of bacteria comes up to the maximum value, the motor 4 is switched into the continuously operating state again through the detector 24 and the controller 27, the bubble breaker 10 is stopped, the pump 3 of an underwater motor is driven, and bubbles on the liquid surface are eliminated by a liquid-spreading type defoamer 23.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for operating an aeration tank that is used for treating livestock human waste and is equipped with a cutter that is rotatably driven in the space above the liquid level and a water sprinkler type defoamer.

BACKGROUND ART Conventionally, it has been widely practiced to install an aeration device in a sewage treatment pit and blow oxygen from the air into the sewage to purify the sewage.

By the way, conventionally, when sewage with a high concentration, such as sewage consisting only of cow and pig excrement or human waste, is treated using an aeration device, the air introduced becomes a floating defoamer, creating a layer of foam on the surface of the sewage. If the sewage treatment tank is a closed type, the upper space will be filled with foam, and if the sewage treatment tank is an open type, the foam will overflow to the ground, making it more difficult for hygiene and maintenance inspection. This may lead to undesirable results.

Bubbles make it impossible to inspect the sewage treatment tank, and removing the bubbles is not easy. Although the above is an example, bubbles may generally be generated when wastewater is aerated or stirred.

However, bubbles are useful for keeping the liquid to be treated in the aeration tank warm, and on the other hand, when bacteria enter the endogenous respiration phase due to aeration, the amount of gas generated in the liquid to be treated increases, causing gas to escape. As the need arises, it is necessary to remove the bubbles and allow the gas to escape.

A defoaming device in an aeration tank is a device invented by Taro Jitsugan / No. 3'l'19 on the left.The defoaming device in an aeration tank is an earthen wall at the top of a closed aeration tank equipped with an aeration device that blows air into the tank that collects wastewater to aerate the tank. A defoaming device for an aeration tank, which is equipped with a foam cutter that is rotated between the surface of the liquid to be treated in the aeration tank, and a water spray type defoamer. ”
Appropriate foam treatment is carried out from the early stage of fermentation until ripening, and since a moderate amount of foam is left in the early stage, it helps to raise the temperature of the liquid to be treated and has the effect of shortening the number of fermentation days.

However, in the above-mentioned design, a bubble detector is provided at the top of the aeration tank, and the bubble condition is determined by the bubble detector, and the bubble cutter and defoamer are operated. Although there is a relationship between the amount of foam generated and the process of composting and fermentation in human waste treatment, the amount of foam generated and the amount of oxygen required do not show a close correspondence. In addition, there are variations in the generation of bubbles, and although it is excellent to have a bubble detector for control, there is a limit to (3) detection control of the composting process using a bubble detector. Therefore, in the above-mentioned idea, the operation of the aeration device is manually controlled.

As described above, the present invention is an aeration tank equipped with an aeration device, a foam cutter equipped with a foam cutter, and a spray defoamer in the human waste treatment, and the present invention provides an appropriate method adapted to the composting process of the human waste treatment using the aeration device. The object of the present invention is to obtain a method for operating an aeration tank equipped with an anti-foaming device that can appropriately operate the anti-foaming device so as to appropriately utilize the foam generated from human waste for heat retention and dissipate gas. be.

FIG. 1 is a flow sheet showing an embodiment of the present invention. At the bottom of the aeration tank, an aeration device (whole number is indicated by C) and a submersible motor pump (whole number is indicated by 3) are installed.

The aeration device is equipped with a motor at the top and a pump 5 at the bottom. A nozzle main body is connected to the discharge port of the pump 5, and a diffuser is connected to the nozzle main body 7 so that it is in a straight line. The nozzle body 7 is provided with a nozzle (not shown), and is connected to a straight air introduction pipe for introducing air that opens in an air chamber near the opening of the nozzle. The air introduction pipe is inserted through the earthen wall of the aeration tank, and the other end of the air introduction pipe is connected to the outlet passage of the outer cylinder of the bubble cutter.

The bubble cutter IO is equipped with a motor 12 inside the outer cylinder l/ with a gap between the outer cylinder // and the outer cylinder /l and the motor/2 are fixed to a base 13 fixed to the outside of the earthen wall. , motor/2
The motor shaft is inserted through the base/3 and the aeration tank/
A foam cutter /4 (equipped with foam cutting blades) is fixed at a position away from the liquid level inside. It leads inside.

The submersible motor pump 3 has a pump 17 connected to the lower part of the motor 1, like a normal submersible motor pump, a discharge pipe 7g is connected to the discharge port of the pump 7, and the discharge pipe 7 is inserted through the earthen wall. It is connected to T-joint /9, and on-off valves -09.21 are fixed on both sides of T-joint /9. A downward outlet pipe 22 connected to an elbow is fixed to the on-off valve SO, and the outlet pipe 2
A defoamer 23 is fixed to the opposite end.

The defoamer 23 is provided with an umbrella-shaped liquid scattering plate spaced apart from the open end of the outlet pipe 2-, and the liquid spouted from the outlet pipe λ hits the liquid scattering plate and widens the liquid level in the aeration tank. It sprays liquid to defoam.

A detector 2'l is attached to the earthen wall to detect the temperature or pH, which is an index indicating the state of the liquid to be treated in the aeration tank.

The on-off valve is connected to a pipe to the secondary storage tank for the next process, a pipe joint, etc. for connection to a tank car for transferring 2S or composted manure to a tank car.

The bubble cutter 10 is a device based on Utility Model Application No. 7/1983, which is suitable for effectively utilizing the heat generated by the motor, but is not limited thereto. 26
is a liquid pipe through which the primary treated liquid of piglet excrement is sent to the aeration tank/aeration tank. The detector 2'l is wired to a control device 27 such as a microcomputer. The control device 27 discriminates the signals sent from the detector and the 2nd circuit and issues commands to control the aeration device, the submersible motor pump 3, and the bubble remover 10. The control signal according to the command is sent to the amplifier circuit. The amplifying circuit 2g opens and closes the output circuit 9. Output image 1 @! Reference numeral 9 supplies electric power to the motor q of the aeration device, the motor 16 of the submersible motor pump 3, and the motor l of the bubble cutter/θ.

In Figure 2, the horizontal axis shows the liquid content of the aeration tank/human waste (hereinafter simply liquid 30).
) indicates the number of days that have passed since the entry.
The vertical axis is a diagram showing the liquid temperature of the liquid 30, PT (and the ambient temperature of the aeration tank).

As shown in Figure 2, the temperature of the liquid 30 filled in the aeration tank from the liquid pipe roller is approximately equal to or slightly higher than the air temperature27.
℃, the bacteria in the liquid 30 also require preparation time to capture organic matter, and the temperature does not reach the temperature required for sufficient bacterial growth. The initial temperature of the liquid 30 is therefore lower during the winter. Therefore, the command from the control device λ is sent to the motors +, / through the amplifier circuit 211, output circuit, and 2q.
(7) The motor l- rotates the cutter/da. Air required for aeration is sucked into the muffler 15 - the outer cylinder//- the air introduction pipe - the nozzle body 7, and is engulfed by the liquid discharged by the pump j at the diffuser t and dispersed into the liquid 30. WL3
Part of the oxygen in the air that has entered the liquid 30 dissolves into the liquid, but the rest rises to the top of the liquid 30 in the form of bubbles. Since the liquid 30 is highly concentrated human waste, the bubbles do not disappear and form a foam layer on the liquid surface. The aeration air cools the motor/2 in the outer cylinder//;
the air is warmed. Therefore, the liquid 30 is initially heated by air having a temperature higher than that of the liquid. From the beginning until the liquid temperature reaches 20 to 30°C, the temperature of the liquid 3θ increases due to fluid friction caused by agitation due to aeration in order to prepare conditions for bacterial growth. Thus, as shown in Figure 1 as an example, when the temperature reaches about 30°C, the growth of bacteria rapidly increases. However, even when the number of bacteria rapidly increases, the total amount of oxygen required is not large, so if you continue to operate the aeration device, it will be exposed. Since it is provided in accordance with the maximum oxygen demand in the latter stage, overaeration occurs and bacteria are killed.Therefore, when the detector 21 detects the liquid temperature 3θL, the signal is sent to the control device 2.
7, the control device core issues a command to operate the Mortag intermittently, and the Mortag enters intermittent operation, for example, running for 2 hours and stopping for 7 hours, via the amplifier circuit-g and the output circuit Cob.
Oxygen supply is limited and adequate oxygen is provided to the bacteria.

On the other hand, since the bubble cutter /θ remained in operation, the bubbles generated were liquefied by the cutter 4' of the bubble cutter 10. Since the defoaming effect of the cutter is limited to the area near where the cutter rotates, the foam layer remains on the liquid surface since the cutter 4' is separated from the liquid surface of the liquid 30. Therefore, the bubble remover IO is operated until the liquid temperature has risen sufficiently and the amount of gas generated from the liquid 3θ is not large. That is, the bubble cutter 10 is continuously operated until the liquid temperature reaches 20 to 30°C, approximately 30°C in the example shown in FIG.

Thus, at the same time as the motor 1 enters intermittent operation, or when the temperature of the liquid 30 rises further and the liquid temperature reaches Vθ~go°C, the amount of bacteria becomes the largest and the generation of bubbles increases, the detector detects
2+ detects the set value of the liquid temperature of about 0°C.-about SO°C, and the signal is sent to the control device 27. The control device = 7 cuts off the power to the motor /:J of the bubble cutter 10, issues an energization command to the motor 16 of the submersible motor pump 3, and controls the amplifier circuit, Zg,
The motor 7.2 is deenergized via the output circuit λ, the motor 6 is energized and the pump 7 is driven, and the pump 7 sucks in the liquid 3θ and sends it out through the discharge pipe 19, The foam on the liquid 30 is extinguished by spraying water with an antifoamer 23 through the opening/closing valve 20 and the outlet pipe 2.2 which have been opened in advance. The spray type defoamer 3 completely extinguishes foam within the spray range. At this point, the liquid 30 is in the process of reaching its maximum amount of bacteria, and the fermentation heat is also increasing, so there is no need to keep it warm, and the amount of gas including steam generated from the liquid 30 is increasing, so it is necessary to dissipate it. comes out. As the temperature of the liquid 30 further rises to qO~SO℃ and the bacteria and bacteria begin to breathe naturally, the oxygen demand reaches near the maximum.Therefore, the detector 2'l detects the temperature t, to When any value is detected, the signal is sent to the control device 7, and the control device 27 switches the motor to continuous operation via the amplifier circuit 2j and the output circuit λ9, and aeration is performed continuously. Alternatively, depending on the state of the liquid 30, the amount of organic matter decreases at this stage, so the intermittent operation of the aeration device λ may be continued. When the temperature of the liquid reaches about 50°C, the temperature will rise due to fermentation heat alone, so you can simply take in the atmosphere.

In this state, the aeration tank is operated and a large amount of gas containing steam is generated above the liquid level. On the other hand, there is a lot of foam generation, but defoamer 23
Since the gas is extinguished by Surface aeration is also performed by water sprinkling. In addition, the defoaming effect of the water sprinkler type defoamer is so remarkable that no bubbles are left on the liquid surface, and since such defoaming may not be necessary depending on the liquid 3θ, the motor lxl/
(b) should be operated alternately to moderate the generation of bubbles (//) and to reduce power costs.

When ripening is completed in this way, motor J/2. /l is cut off, on-off valve θ is closed, on-off valve 2/ is opened, and liquid 3θ is pumped out by pump /7 and sent out from pipe 2j.

When the detector is used to detect the pH of the liquid 30, the temperature of the liquid is related to the pH, so the same control as described above is performed using the pH corresponding to the temperature. As shown in FIG. 2, the PH corresponding to a temperature of about 30° C. is initially saturated at g and o, so the aeration device λ is switched to intermittent operation near PHg, which is slightly smaller than that. Temperature lIo
For example, the PH corresponding to the temperature between -go℃ is If,
Since the value is 2, the foam cutter 10 is stopped at PH, S', and 2, and the liquid is sent to the defoamer 3. Since the PH value corresponding to the temperature of about ps° C. is saturated, the aeration equipment is switched to continuous operation near the P value, which is smaller than the PHg value.

Alternatively, continue intermittent operation when the amount of organic matter is decreasing.

As described above, according to the method of operating an aeration tank equipped with a foam cutter, a dispersion-type extinguisher (/2), and an aeration device according to the present invention, bubbles are removed by the action of the foam cutter during the preparatory period for bacterial growth. The aeration equipment remains at a moderate level above the liquid level and is operated continuously to raise the temperature. Additionally, the input to the foam cutter motor is transferred as heat into the aeration tank.

When the bacteria enters the growth phase, it is necessary to operate intermittently to prevent over-aeration and at the same time measure the temperature rise, so the foam cutter is operated and the foam is left behind. When the amount of bacteria approaches the maximum amount, the bubble cutter is stopped and either a water spray type defoamer is used to extinguish the bubbles on the liquid surface, or the bubble cutter and defoamer are operated alternately to eliminate the gas in the liquid. Make it easier to escape. At this time, the amount of liquid is at its maximum due to fermentation heat, so continuous aeration is performed, or intermittent aeration is continued depending on the amount of organic matter remaining. This process is carried out automatically, and the aeration treatment of livestock human waste is carried out in an optimal manner.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet explaining the present invention in detail, and FIG. 2 is a diagram showing the relationship between the number of days of composting and the condition of human urine in FIG. 1. /... Aeration tank λ... Aeration system f 3... Submersible motor pump 7' 4 (... Motor!... Pump 7... Nozzle body g... Diffuser?... Air introduction pipe 10...
Foam cutter //・・Outer cylinder /, 2・・Motor /3・−
Base /G...Bubble cutter 15...Silencer /6
・・Motor 17・-Pump /r・・Discharge pipe /9・
・T joint 20・・Opening/closing valve , 2/・・Opening/closing valve here・・
Outlet pipe 3... Defoamer 21I... Detector 2S...
Piping 26...Liquid pipe Core...Control device 2g...Amplification circuit: t9...Output circuit 3θ...Liquid. Patent applicant Ebara Corporation Agent Arai -be

Claims (1)

[Claims] / A method for operating an aeration tank equipped with a foam cutter, a liquid defoamer, and an aeration device, in which human waste is placed in the aeration tank and aeration is performed by the aeration device. The tank is equipped with a detector that detects the physical or chemical state of the human waste, and a signal generated when the detector detects the state of the human waste is sent via a control device to the vicinity where the initial bacteria in the composting process begin to sufficiently proliferate. The aeration equipment is operated continuously until the temperature reaches the temperature, and if necessary, the temperature of the human waste is raised mainly by stirring the human waste, and the detector detects the seventh index indicating the condition of the nearby human waste in the early state of the growth phase where bacteria begin to multiply. The detection and control device operates the aeration equipment intermittently to match the bacterial growth period to reduce the amount of oxygen supplied.On the other hand, it is necessary to leave a foam layer on the liquid surface from the beginning of the aeration to keep it warm, and the gas generated from human waste is The bubble cutter is operated for a short period of time, and the need for heat insulation is eliminated due to the generation of fermentation heat.The detector detects the value of the first index, which increases the amount of gas generated from human waste, and the bubble cutter is removed via the control device. A method of operating an aeration tank equipped with an antifoaming device that stops a cutting machine and drives a pump that sends liquid to a liquid dispersion type antifoaming device, or alternately operates the pump. The index detected by the detector is the temperature of human waste, the first index is the temperature of about 0 to 30℃, and the first index is the temperature of about 10℃.
A method of operating an aeration tank equipped with an antifoaming device according to claim 1 at -10°C. 3 The indicator detected by the detector is the acidity of human waste, which is the seventh
PHff is less than the initial saturated acidity PHg
2. A method for operating an aeration tank equipped with an antifoaming device according to claim 1, wherein the first index is near about PHg,l.