JPH0227311B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating compost by biochemical treatment of human waste from livestock.

Traditionally, agriculture was usually carried out using chemical fertilizers, but chemical fertilizers alone reduce the fertility of the soil and lead to soils lacking in organic matter, so in recent years, organic fertilizers have been used instead of chemical fertilizers. Things that should be done are being encouraged. However, organic fertilizer is derived from the excrement of livestock such as cows and pigs, and if it is applied as raw manure, the nitrogen content will flow down strongly and flow into rivers and lakes, causing pollution. If you apply fertilizer directly to grass, it will die. Also, from the cow's point of view, the grass has a bitter taste, and from the human's point of view, the odor is intolerable. In particular, the production of nitrified nitrogen compounds can cause diseases in cattle.

Therefore, livestock manure is fermented and turned into compost.

Various proposals have been made for composting livestock manure, but fermentation using aerobic bacteria is generally used as composting. To promote composting, livestock manure is separated into solids and liquid (hereinafter sometimes simply referred to as liquid) and the liquid is stored in an aeration tank, and air is blown into the wastewater in the aeration tank to create aerobic bacteria. This is where composting is widely practiced. As a method of providing oxygen to these aerobic bacteria, an aeration device is installed in the aeration tank, the liquid in the aeration tank is pumped up and sent to the ejector, air is taken in from the air intake port of the ejector, and it is squirted into the aeration tank liquid. This method is common for treating livestock human waste.

Conventionally, composting using such an aeration device takes about 10 days in an aeration tank, during which time the state of composting of human waste in the aeration tank is monitored by input. For this reason, the temperature and pH of the liquid in the aeration tank are measured, but the process relies mostly on feeling. Because measurements are not taken continuously, when the liquid temperature does not rise during the fermentation process, aeration may cause excess oxygen supply and kill the bacteria, or the aeration may not be carried out properly, resulting in slow bacterial growth and spoilage. There are problems in that the fermentation is delayed and the processing time is too long.

The present invention aims to accurately understand the process of fermenting and composting livestock human waste through the action of aerobic bacteria through aeration, provide an appropriate supply of oxygen, promote the composting process, and automate these processes. The purpose is to

The present invention is provided with a thermometer that detects the temperature of the human waste in the aeration tank when liquid human waste is placed in the aeration tank and aeration is performed by an underwater aeration device, and the thermometer detects the state of the human waste and generates water. Based on the signal, the submersible aeration system is operated continuously through the control device until it reaches a temperature of 20 to 30 degrees Celsius, at which the initial bacteria in the composting process begin to sufficiently proliferate, and then a thermometer signal is sent to indicate that this temperature has been reached. This is an aeration method for human waste treatment in which the amount of oxygen supplied is reduced by intermittent operation of the underwater aeration system through a control device to match the bacterial growth period.

Hereinafter, the present invention will be explained based on the drawings. In FIG. 1, the horizontal axis shows the number of days that have passed for the liquid content of livestock human waste placed in the aeration tank. The vertical axis shows the air temperature and the liquid temperature in the aeration tank, and FIG. 2 is a flow sheet of the present invention. Although the aeration tank 1 in FIG. 2 is a single tank, the same is true even if the aeration tank is divided, as long as aerobic treatment is carried out, the liquid to be treated is simply transferred during the process.

In the present invention, a thermometer 3 is provided in the liquid 2 of the aeration tank 1, and the signal from the thermometer 3 is sent to the control device 4 as an electric signal.
sent to. The control device 4 includes, for example, a microcomputer, an amplification circuit, and an output circuit, and its output drives a pump 6 by a motor 7 provided in the aeration tank 1 to send liquid to an ejector 5, which is connected to an air introduction pipe 8. It opens to the atmosphere through.

The thermometer 3 measures the temperature of the human waste, which is related to changes in the amount of oxygen required during the composting process of the human waste.

The temperature of the liquid placed in aeration tank 1 is 21℃,
This is approximately equal to or slightly higher than the temperature. Therefore, when the air temperature is low, the temperature of the liquid 2 is also initially low. When the aeration tank 1 is filled with the liquid 2, the motor 7 is energized, the pump 6 is driven, and the liquid flowing out from the pump 6 is injected through a nozzle in the ejector 5.
Air inlet pipe 8 due to vacuum pressure generated around the injected liquid column
The air sucked into the liquid is sucked into the injection liquid and is ejected from the ejector 5 into the liquid 2 to perform aeration.

In the example shown in Figure 1, the liquid 2 placed in the aeration tank 1 is at a temperature of approximately 21°C, in which bacteria are not proliferating. It is a preparatory period for
The temperature is not suitable for bacteria to grow. Therefore, the aeration device operates continuously, the motor 7 radiates heat, and the liquid 2
The liquid 2 is sucked into the pump 6, discharged into the aeration tank 1 via the ejector 5, and stirred by the stirring heat.
increases in temperature. These heats are almost equal to the input to the motor 7, although the fermentation heat caused by the bacteria is still insignificant. After this initial stage, the amount of bacteria increases as the liquid temperature increases. Oxygen consumption also increases accordingly. Since the aeration tank 1 is a closed tank and the temperature of the liquid is low, the amount of heat released is small, and the liquid 2 rises linearly up to about 30°C in the example shown in Figure 1.

In addition, in cold regions, the temperature of the liquid 2 placed in the aeration tank 1 may be around 5°C, for example, and in this case, the first index is lower than about 30°C.
It will be between 20℃ and 30℃. It also changes depending on what kind of human waste the liquid 2 is.

Example 30 in Figure 1 where the state of human waste is the primary indicator
As the liquid temperature approaches around ℃, the temperature in liquid 2 becomes suitable for the growth of aerobic bacteria, and the rate of increase in bacteria increases. In addition, the generation of fermentation heat due to bacteria gradually increases. However, even if the temperature is suitable for bacterial growth, the amount of oxygen consumed is not large.
Then, the control device 4 receives a signal detected by the thermometer 3.
determines that the liquid temperature has reached a temperature between 20 and 30°C, which is the first index set according to the initial conditions of liquid 2, and operates the motor 7 intermittently to limit the aeration air. do. In this state, bacteria are in the process of multiplying. Therefore, if you give more oxygen than the bacteria need, the bacteria will die. That is, since the aeration device has the necessary capacity for oxygen consumption in the latter half of the aeration period, if the aeration device is operated continuously, overaeration will occur. Therefore, the control device 4
Motor 7 is activated by a timer preset in
The power is turned on for two hours, the power is cut off for the next hour, and the power is turned on again to operate for two hours and rest for one hour. These times and intervals are illustrative and are selected so that an appropriate amount of oxygen is supplied so as not to kill bacteria due to over-aeration. Therefore, this intermittent electric rotation is caused by motor 7.
It is preferable that if the energization time to the motor 7 is constant, the time for which the motor 7 is de-energized is gradually shortened as the fermentation process progresses.

If aeration is performed in steps starting from the liquid temperature of about 30°C, which is the first indicator in the example in Figure 1, the rate of bacterial growth will increase and the generation of fermentation heat will increase, causing the liquid temperature to become the second indicator. As the temperature approaches 40°C to 50°C, the rate of temperature increase gradually decreases, and the rate of bacterial growth also decreases. If necessary, when the liquid temperature reaches 40°C to 50°C, which is the second indicator indicating the state of human waste, the controller 4 continuously energizes the motor 7 based on a signal sent to the controller 4 of the thermometer 3. , aeration is carried out. At this stage, the bacteria in liquid 2 proliferate rapidly, and the amount of bacteria reaches its maximum and enters the auto-respiration period, which requires a large amount of oxygen, so the aeration equipment must be operated at 100% capacity. Alternatively, since the amount of organic matter decreases when the temperature exceeds 50°C, the amount of oxygen required may be reduced, so the temperature is maintained constant by intermittent operation.

Thus, the ripening of liquid 2 is completed after a certain period of about three days as shown in FIG. 1 at a temperature of 40°C to 50°C.

As described above, the present invention is applicable to the case where liquid human waste is placed in an aeration tank and aeration is performed using an underwater aeration device.
Equipped with a thermometer to detect the temperature of human waste in the aeration tank,
The thermometer detects the state of the human waste and generates a signal, which is used by the control device to operate the submersible exposure device continuously until it reaches a temperature of 20 to 30 degrees Celsius, at which the initial bacteria in the composting process begin to grow sufficiently, and then, When the thermometer signal indicates that this temperature has been reached, the control device operates the submersible aeration system intermittently to reduce the amount of oxygen supplied, which corresponds to the bacterial growth period. The death of bacteria or suppression of proliferation is prevented, and the underwater aeration device is operated intermittently during the process, resulting in lower power costs. In addition, when composting matures and bacteria require oxygen, the submersible aeration system is operated continuously in order to avoid over-aeration and the aeration system is made small to avoid oxygen deficiency. This means that sufficient oxygen can be supplied.

[Brief explanation of drawings]

FIG. 1 is a diagram showing changes in liquid temperature in the aeration tank during the composting and fermentation process of human waste, and FIG. 2 is a flow sheet showing the aeration method of the present invention. 1... Aeration tank, 2... Liquid, 3... Thermometer, 4... Control device, 5... Ejector, 6... Pump, 7... Motor, 8
...Air introduction pipe.

Claims (1)

[Claims] 1. When liquid human waste is placed in an aeration tank and aeration is performed by an underwater aeration device, a thermometer is provided in the aeration tank to detect the temperature of the human waste, and the thermometer detects the state of the human waste. Based on the signal generated by the controller, the underwater aeration system is operated continuously until it reaches a temperature of 20 to 30 degrees Celsius, at which the initial bacteria in the composting process can sufficiently proliferate, and then the temperature is set to indicate that this temperature has been reached. An aeration method for human waste treatment in which the submersible aeration device is operated intermittently to match the bacterial growth period using a control device based on a signal from the meter to reduce the amount of oxygen supplied. 2 Following the above-mentioned human waste treatment, the amount of bacteria reaches its maximum and the amount of oxygen required approaches the maximum value, and a temperature of 40° to 50°C, which indicates the state of the urine, is detected and the underwater aeration system is activated via the control device based on the signal. An aeration method for human waste treatment according to claim 1, which operates continuously.