JP7441453B2 - Water quality improvement equipment and water quality improvement method - Google Patents

Description

The present invention relates to a water quality improvement device and a water quality improvement method.

Traditionally, it has been used in various fields such as improving water quality in building pits and combined septic tanks, controlling blue-green algae in dams, preventing rot in cooling water in factories, reducing suspended matter in sewage treatment plants, and stirring bioreactors that perform biochemical reactions using biocatalysts. Therefore, efficient treatment at water treatment facilities is required, and various technologies have been proposed. Basically, by exposing water to air and supplying air to the water liquid (waste liquid), the dissolved oxygen rate in the waste liquid is improved, and scum (suspended matter/precipitates) in the liquid is generated. This aims to prevent and avoid the occurrence of odor and odor.

A typical aeration device has a structure that discharges air directly above the water. When treating waste liquid, increase the dissolved oxygen rate using microbubbles, etc., crush scum etc. with strong stirring force, and aim for homogenization with this circulating flow, making the oxygen supply to the waste liquid more efficient and eliminating the cause of bad odors. This avoids becoming a reduced state.

For example, the techniques disclosed in Patent Documents 1 to 3 have attracted attention as effective means for improving water quality by decomposing scum and odor-causing substances caused by suspended matter and sediments of microorganisms. There is. Patent Documents 1 to 3 disclose a method in which waste liquid is introduced into a flow path in a pipe of an ejection means installed vertically in a storage tank and is raised without the need for a stirring device such as a pump or a propeller blade. A technique has been disclosed in which a physical stimulus (vibration) is applied to this waste liquid, and the air is made finer and segmented to force circulation and agitation to the waste liquid in the tank.

FIG. 9A is an explanatory diagram of the circulating flow generator described in Patent Document 1. A spouting means 1 having a spouting pipe 2 is provided upright within the storage tank 4 . The jetting pipe 2 is provided with a waste liquid flow path 2a and a gas flow path 2b. Furthermore, an air supply mechanism 3 having an air chamber 3a communicating with the gas flow path 2b is provided. The circulating flow generator 5 is configured as described above. When treating the waste liquid in the storage tank 4, the ejection means 1 takes in the waste liquid in the storage tank 4 from the bottom side and discharges it from the top side, thereby circulating the waste liquid. Here, the air introduced from the air chamber 3a is mixed with the waste liquid and dispersed, and the gas-liquid mixed waste liquid is circulated.

FIG. 9B is an explanatory diagram showing the basic configuration of the gas-liquid mixed circulating flow generator described in Patent Document 2. A jetting means 1 having a jetting pipe 2 is provided. The jetting pipe 2 is provided with a waste liquid flow path 2a. Furthermore, an air supply mechanism 3 having an air chamber 3a and a gas flow path 3b is provided. During waste liquid treatment, the ejection means 1 takes in the waste liquid in the storage tank from the bottom side and discharges it from the top side, thereby circulating the waste liquid. Here, the air introduced from the air chamber 3a is mixed with the waste liquid and dispersed to generate a swirling flow of the gas-liquid mixed waste liquid and circulate it.

Patent Document 3 discloses a method and device for improving water quality by activating microorganisms in water. By introducing air and generating a high-speed jet upward flow to generate a high-speed circulating upward flow, microorganisms in the water are activated and water quality is improved.

Japanese Patent Application Publication No. 2002-045667 Japanese Patent Application Publication No. 2011-152534 Japanese Patent Application Publication No. 2018-187558

However, when treating waste liquid in a storage tank, it is required to strengthen the swirling upward flow that circulates the waste liquid and to increase the gas-liquid mixing efficiency between the waste liquid and air.

An object of the present invention is to provide a water quality improvement device that can improve the water quality of waste liquid by strengthening the swirling upward flow that circulates waste liquid and increasing the gas-liquid mixing efficiency between waste liquid and air when treating waste liquid in a storage tank. and to provide a method for improving water quality.

As a result of intensive research, the applicant of this patent has developed a method for applying strong physical stimulation to the ejecting means to raise the waste liquid flow path of the ejecting means when treating waste liquid in the storage tank. The captured air is discharged from the gas flow path through the discharge port into the waste liquid flow path, and the rising waste liquid and the released air collide and synthesize, creating a strong swirling upward flow of gas-liquid mixture. Equipped with a bubbling section, this is forced to circulate widely within the storage tank to increase dissolved oxygen in the waste liquid in the tank, and to coexist and grow not only aerobic microorganisms but also aerobic and anaerobic microorganisms in a well-balanced manner. We have discovered a technology that can improve water quality.

The water quality improvement device of the present invention is a water quality improvement device that improves the water quality of the waste liquid by circulating the waste liquid containing microorganisms stored in the storage tank in the storage tank and activating the microorganisms, A cylindrical shape having a waste liquid flow path that takes in the waste liquid from the bottom side and discharges it from the top side, and a gas flow path that communicates with the waste liquid flow path and releases air into the waste liquid flow path. an air supply having an air chamber provided with a blowout pipe and a supply port that stores air introduced from outside the storage tank and communicates with the gas flow path to supply the stored air to the gas flow path; and an air introduction part provided outside the storage tank to introduce air into the air chamber, and the gas flow path includes a first discharge port provided in communication with the waste liquid flow path. and a second gas flow path having a second discharge port that is different from the first discharge port in a distance from the bottom surface of the jet pipe and that is provided in communication with the waste liquid flow channel. include.

The water quality improvement method of the present invention is a water quality improvement method that improves the water quality of the waste liquid by circulating the waste liquid containing microorganisms stored in the storage tank in the storage tank and activating the microorganisms, A cylindrical ejection pipe having a waste liquid flow path, a first gas flow path having a first discharge port provided in communication with the waste liquid flow path, and a distance from the bottom of the ejection pipe to the first gas flow path. In the spouting pipe, the spouting pipe is provided with a gas flow path including a second gas flow path having a second gas flow path that is different from the first discharge port and is provided in communication with the waste liquid flow path. A step of taking in air from the bottom side of the pipe and discharging it from the top side of the jet pipe, and storing air introduced from the outside of the storage tank and communicating with the gas flow path to send the stored air. By introducing air from outside the storage tank into an air chamber provided with an inlet, and simultaneously performing the steps of releasing air from the first discharge port and the second discharge port, the waste liquid is removed. Circulate within the storage tank.

According to the present invention, when treating waste liquid in a storage tank, the swirling upward flow that circulates the waste liquid can be strengthened by the synergistic effect of bubbling caused by the air released from the discharge ports at different heights. It can strengthen the stimulation. Furthermore, the synergistic effect of the bubbling mentioned above can increase the gas-liquid mixing efficiency between the waste liquid and air, which increases the amount of dissolved oxygen in the waste liquid in the tank. Both anaerobic microorganisms can coexist in a well-balanced manner, and the generation of bad odors can be prevented.

FIG. 1 is an explanatory diagram of a storage tank to which a water quality improvement device according to an embodiment of the present invention is applied. FIG. 2 is a schematic vertical cross-sectional view of the spout section of the water quality improvement device shown in FIG. FIG. 3 is an explanatory diagram showing the arrangement of the jet pipe and the air supply section of the water quality improvement device of FIG. 1. FIG. 4 is an explanatory diagram showing the outlet of the jet pipe of the water quality improvement device of one embodiment. FIG. 5 is an explanatory diagram schematically showing each discharge port of the jet pipe of the water quality improvement device of one embodiment. FIG. 6A is a plan view showing the shape of an example of the outlet. FIG. 6B is an explanatory diagram schematically showing how air is discharged from the discharge port shown in FIG. 6A. FIG. 7 is an explanatory diagram showing repeated circulation of waste liquid in the storage tank. FIG. 8 is an explanatory diagram showing the activation status of anaerobic and anaerobic microorganisms. FIG. 9A is an explanatory diagram of a conventional circulating flow generator. FIG. 9B is an explanatory diagram of a conventional gas-liquid mixed circulating flow generator.

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

FIG. 1 is an explanatory diagram of a storage tank to which a water quality improvement device according to the present embodiment is applied. The storage tank 10 is provided in a water treatment facility and stores waste liquid WL to be treated. The storage tank 10 is surrounded by a closed side surface 10a, a bottom surface 10b, and a top surface 10c. The upper surface portion 10c is provided with an opening such as a manhole. The storage tank 10 is also provided with an inflow pipe 16 through which the aqueous liquid flows, and a drain pipe 17 through which the waste liquid WL treated in the storage tank 10 is drained.

The water quality improvement device applied to the storage tank 10 improves the water quality of the waste liquid WL by circulating the waste liquid WL containing microorganisms stored in the storage tank 10 in the storage tank 10 and activating the microorganisms. It is a device. Microorganisms may include fungi.

FIG. 2 is a schematic vertical cross-sectional view of the spout section 11 of the water quality improvement device according to this embodiment. The water quality improvement device includes a blowout pipe 12, an air supply section 14, and an air introduction section 15.

The jet pipe 12 has a jet pipe main body 12a having a substantially cylindrical shape. The ejection pipe body 12a is provided with a waste liquid channel 13 extending in the Z direction, which takes in the waste liquid WL from the bottom side and discharges it from the top side. The waste liquid flow path 13 has a substantially cylindrical inner wall surface 13a and a tapered portion 13b in which the flow path diameter increases at the upper side. Further, a gas flow path 12b including a first gas flow path 12bx and a second gas flow path 12by communicating with the waste liquid flow path 13 and discharging air into the waste liquid flow path 13 is provided. The first gas flow path 12bx and the second gas flow path 12by are also collectively referred to as the gas flow path 12b. The gas flow path 12b has a first gas flow path 12bx having a first discharge port 121bx provided in communication with the waste liquid flow path 13, and a second discharge port 121by provided in communication with the waste liquid flow path 13. and a second gas flow path 12by. The first discharge port 121bx and the second discharge port 121by are also collectively referred to as the discharge port 121b. The distance of the second discharge port 121by from the bottom surface of the jet pipe 12 is different from that of the first discharge port 121bx. The distance from the bottom of the jet pipe 12 is the length in the Z direction from the bottom of the jet pipe 12 in FIG. 2, and is the height of the jet pipe 12 from the bottom. FIG. 2 shows, as an example of the height H1 of the first discharge port 121bx and the height H2 of the second discharge port 121by, that the difference S between them is 50 mm.

The air supply unit 14 has a substantially annular (doughnut-shaped) air chamber main body 14a, and a hollow air chamber 14b is provided inside. The air chamber 14b stores air introduced from outside the storage tank 10, and is provided with a supply port 14d that communicates with the gas flow path 12b and supplies the air stored in the air chamber 14b to the gas flow path 12b. ing. The air chamber 14b is provided with a vent 14c, and is configured to be able to supply air from the outside to the inside of the air chamber 14b.

FIG. 3 is an explanatory diagram showing the arrangement of the jet pipe and the air supply section of the water quality improvement device according to the present embodiment. As shown in FIGS. 2 and 3, the ejection pipe 12 is installed upright within the storage tank 10 while being inserted into the air supply section 14. The air supply part 14 is in contact with the flange part 12c stretched at a desired location, and both are assembled with bolts 12d. Regarding this assembly, conventionally known assembly means can be appropriately employed.

The ejection pipe 12 and the air supply section 14 are integrally assembled to form the ejection section 11. The ejection pipe 12 and the air supply section 14 are aligned and assembled so that the gas flow path 12b and the supply port 14d communicate with each other, and are configured to function as the ejection section 11.

The first gas flow path 12bx and the second gas flow path 12by are depicted as flow paths extending in the XZ plane in FIG. 2, but in FIG. It is merely shown schematically that the two discharge ports 121by are communicated with each other by the first gas flow path 12bx and the second gas flow path 12by. That is, the first gas flow path 12bx and the second gas flow path 12by do not extend in the XZ plane as described later. Details of the first gas flow path 12bx having the first discharge port 121bx and the second gas flow path 12by having the second discharge port 121by will be described later.

As shown in FIG. 1, the air introduction part 15 is provided outside the storage tank 10 and is configured to introduce air into the air chamber 14b. As shown in FIG. 1, the air introduction section 15 includes a pump 15a having an air introduction port 15b, and a ventilation path 15c is connected to the pump 15a. The ventilation path 15c extends into the storage tank 10 and is connected to the ventilation port 14c. The air introduction section 15 allows air to flow into the air chamber 14b.

As shown in FIG. 2, the spouting part 11 is placed on a fixing base 18, and the fixing base 18 on which the spouting part 11 is placed is placed on the bottom of the storage tank 10. . The fixing base 18 is composed of a base material 18a and legs 18b on which the ejection part 11 is placed, but is not limited to this as long as it has such an effect.

The spout pipe 12 is provided with a waste liquid channel 13 extending in the Z direction at the center so as to take in the waste liquid WL in the storage tank 10 from the bottom side and discharge it from the top side. The waste liquid WL in the storage tank 10 is taken in from the bottom of the storage tank 10 (spouting part 11) and raised to the top side of the spouting part 11.

The first gas flow path 12bx and the second gas flow path 12by are gas flow paths formed in the ejection pipe 12 (vertically provided in the radial width direction) for flowing air, and their lower ends are connected to the air chamber. The supply ports 14b and 14d each communicate with the supply ports 14d. The upper ends of the first gas flow path 12bx and the second gas flow path 12by gradually taper, and a first discharge port 121bx and a second discharge port 121by are formed at their tips facing the flow channel inner wall surface 13a of the waste liquid flow path 13, respectively. It is formed. The first gas flow path 12bx and the second gas flow path 12by are formed diagonally across the inside of the ejection pipe 12. The first discharge port 121bx and the second discharge port 121by are inclined at an acute angle.

The detailed structure and operation of the gas flow path 12b will be explained with reference to FIGS. 4(a) to 4(d) and FIG. 5. FIGS. 4(a) to 4(d) are explanatory diagrams showing the discharge port of the jet pipe 12 of the water quality improvement device according to one embodiment, and the gas flow path 12b and the discharge port 121b in the XY plane at different heights. The direction of the gas is schematically shown. FIG. 5 is an explanatory diagram schematically showing each discharge port of the jet pipe 12 of the water quality improvement device according to one embodiment, and the discharge ports in FIGS. 4(a) to 4(d) are shown together in one diagram. It is something. 4A to 4D and FIG. 5 show an example in which there are four gas channels 12ba, 12bb, 12bc, and 12bd whose distances from the bottom of the jet pipe 12 of the discharge port 121b are different from each other. Although an example having four gas flow paths is shown here, the number is not limited to four, and any number may be used.

As shown in FIGS. 4(a) to 4(d) and FIG. 5, it has, for example, four gas flow paths 12ba, 12bb, 12bc, and 12bd. The respective discharge ports 121ba, 121bb, 121bc, and 121bd of the four gas flow paths 12ba, 12bb, 12bc, and 12bd are provided so as to be located within a width range of 50 mm in the vertical direction of the waste liquid flow path 13. Note that the vertical width of the waste liquid channel 13 of the discharge ports 121ba, 121bb, 121bc, and 121bd is preferably within a range of 5 mm to 10 mm. If the heights of the outlets 121ba, 121bb, 121bc, and 121bd are too close or too far apart, it becomes difficult to obtain the synergistic effect of bubbling caused by the air released from the outlets. The respective discharge ports 121ba, 121bb, 121bc, and 121bd of the four gas flow paths 12ba, 12bb, 12bc, and 12bd are on a virtual spiral line that rotates upward in sequence. Air is discharged from each discharge port 121ba, 121bb, 121bc, and 121bd arranged at regular intervals.

The four gas channels 12ba, 12bb, 12bc, and 12bd and the four discharge ports 121ba, 121bb, 121bc, and 121bd will be described. First, as shown in FIG. 4(a), the gas flow path 12ba and the discharge port 121ba will be explained. The air discharged into the waste liquid flow path 13 from the uppermost discharge port 121ba on the flow path inner wall surface 13a of the waste liquid flow path 13 is slanted to the right from the center left in the figure, and is slightly upwardly moving along the flow path inner wall surface 13a. It is released as a swirling flow towards. The direction in which the air is discharged is projected onto the XY plane, for example, in a direction that makes an angle of 15 degrees with the normal direction of the channel inner wall surface 13a at the discharge port 121ba.

As shown in FIG. 4(b), the gas flow path 12bb and the discharge port 121bb will be explained. The air discharged into the waste liquid flow path 13 from the next stage discharge port 121bb on the flow path inner wall surface 13a of the waste liquid flow path 13 is diagonally to the right from the upper center in the figure, and is slightly upwardly moving along the flow path inner wall surface 13a. It is released as a swirling flow towards. The direction in which the air is discharged is projected onto the XY plane, for example, at a 60 degree angle with the normal direction of the channel inner wall surface 13a at the discharge port 121bb.

As shown in FIG. 4(c), the gas flow path 12bc and the discharge port 121bc will be explained. The air discharged into the waste liquid flow path 13 from the next stage discharge port 121bc on the flow path inner wall surface 13a of the waste liquid flow path 13 is diagonally left from the center right in the figure, and is slightly upwardly moving along the flow path inner wall surface 13a. It is released as a swirling flow towards. The direction in which the air is discharged is projected onto the XY plane, for example, at a 45 degree angle with the normal direction of the channel inner wall surface 13a at the discharge port 121bc.

As shown in FIG. 4(d), the gas flow path 12bd and the discharge port 121bd will be explained. The air discharged into the waste liquid flow path 13 from the lowest discharge port 121bd on the flow path inner wall surface 13a of the waste liquid flow path 13 is diagonally to the left from the bottom center in the figure, and is slightly upwardly moving along the flow path inner wall surface 13a. It is released as a swirling flow towards. The direction in which the air is discharged is projected onto the XY plane, for example, in a direction that makes an angle of 30 degrees with the normal direction of the channel inner wall surface 13a at the discharge port 121bd.

Each of the discharge ports 121ba, 121bb, 121bc, and 121bd facing the inner wall surface 13a of the waste liquid flow path 13 preferably has a teardrop-shaped cross-sectional shape with respect to the waste liquid flow path 13. That is, it is preferable that the air be discharged in the direction of an imaginary spiral line in which air is swirled and ascends, and that the cross-sectional shape of the flow channel inner wall surface 13a is a teardrop-shaped discharge port. As for the cross-sectional shape of the channel inner wall surface 13a, it is preferable that the waste fluid is discharged into the waste fluid channel 13 from teardrop-shaped discharge ports 121ba, 121bb, 121bc, and 121bd.

FIG. 6A is a plan view showing an example of the shape of the above-mentioned outlet. That is, it shows the shape of the outlet when the substantially cylindrical curved surface is made into a flat surface. In the example of FIG. 6A, the outlet 121b has a teardrop shape. The teardrop-shaped shape is, for example, a shape in which a part of the circumferential portion of a circular shape is stretched in the outer circumferential direction. The example of the discharge port 121b shown in FIG. 6A has a shape in which a semicircular portion P1 and a protruding portion P2 that is elongated in the outer circumferential direction than the semicircle are smoothly connected.

FIG. 6B is an explanatory diagram schematically showing how air is released from the outlet shown in FIG. 6A. The discharge port 121b is inclined at an acute angle with respect to the gas flow path 12b, and a semicircular portion P1 is arranged on the inner wall surface side of the flow path with respect to the air flow F released from the gas flow path 12b, and the air flow is The protrusion P2 is arranged on the waste liquid flow path 13 side with respect to F.

According to the above water quality improvement device, the discharge ports 121ba, 121bb, 121bc of the four gas flow paths 12ba, 12bb, 12bc, 12bd, which are on a virtual spiral line, have different heights, and are arranged at regular intervals, Air is released from 121bd and a swirling upward flow is generated. Each swirling upward flow sequentially swirls upward, and does not collide with each other and cancel each other out, but synergistically interferes with each other. As a result, the rising waste liquid WL is turned into a strongly bubbling gas-liquid mixed waste liquid (strongly bubbling gas-liquid mixed waste liquid), and this strongly bubbling gas-liquid mixed waste liquid is spread over a wide range in the storage tank 10. forced circulation.

The discharge ports 121ba, 121bb, 121bc, and 121bd of the four gas channels 12ba, 12bb, 12bc, and 12bd are located close to each other within a range of 50 mm above and below within the waste liquid channel 13 of the channel inner wall surface 13a, They synergize and interfere with each other and are synthesized.

According to the water quality improvement device of this embodiment, the swirling upward flow that circulates the waste liquid WL can be strengthened due to the synergistic effect of bubbling, and thereby the physical stimulation repeatedly applied to the waste liquid WL can be strengthened. Furthermore, due to the synergistic effect of the bubbling mentioned above, it is possible to increase the gas-liquid mixing efficiency between the waste liquid WL and air, thereby increasing dissolved oxygen in the waste liquid in the tank, and not only aerobic microorganisms but also aerobic - Both anaerobic microorganisms can coexist in a well-balanced manner, and the generation of bad odors can be prevented.

The water quality improvement method using the water quality improvement device of this embodiment improves the water quality of the waste liquid WL by circulating the waste liquid WL containing microorganisms stored in the storage tank 10 in the storage tank 10 and activating the microorganisms. This is a water quality improvement method. A cylindrical ejection pipe 12 having a waste liquid flow path 13, a first gas flow path 12bx having a first discharge port 121bx provided in communication with the waste liquid flow path 13, and a first gas flow path 12bx from the bottom of the ejection pipe 12. An ejection pipe 12 in which a gas flow path 12b including a second gas flow path 12by having a second discharge port 121by which is different in distance from the first discharge port 121bx and is provided in communication with the waste liquid flow path 13 is bored. , a step of taking in the waste liquid WL from the bottom side of the spout pipe 12 and discharging it from the top side of the spout pipe 12, and storing the air introduced from the outside of the storage tank 10 and communicating with the gas flow path 12b. A step of releasing air from the first discharge port 121bx and the second discharge port 121by by introducing air from outside the storage tank 10 into the air chamber 14b provided with the supply port 14d through which the stored air is sent. By performing these simultaneously, the waste liquid WL is circulated within the storage tank 10.

According to the water quality improvement method of this embodiment, the swirling upward flow that circulates the waste liquid WL can be strengthened due to the synergistic effect of bubbling, and thereby the physical stimulus repeatedly applied to the waste liquid WL can be strengthened. Furthermore, due to the synergistic effect of the bubbling mentioned above, it is possible to increase the gas-liquid mixing efficiency between the waste liquid WL and air, thereby increasing dissolved oxygen in the waste liquid in the tank, and not only aerobic microorganisms but also aerobic - Both anaerobic microorganisms can coexist in a well-balanced manner, and the generation of bad odors can be prevented.

FIG. 7 is an explanatory diagram showing the repetition of circulation of the waste liquid WL in the storage tank. The swirling upward flows A and B of the gas-liquid mixture discharged from the waste liquid channel 13 of the spouting part 11 are forcibly pushed out over a wide range within the storage tank 10 . As a result, the waste liquid WL is stirred above the waste liquid flow path 13. The waste liquid WL in the storage tank 10 is repeatedly recirculated by the swirling upward flows A and B that are strongly bubbled in the waste liquid flow path 13.

As shown in FIG. 7, the swirling upward flows A and B from the jetting part 11 stir the gas-liquid mixed waste liquid over a wide area in the storage tank 10, and generate circulation flows C and D that circulate downward. , the waste liquid WL is stirred and recirculated throughout the storage tank 10.

The swirling upward flow of the gas-liquid mixed waste liquid generated inside the channel inner wall surface 13a of the above-mentioned spouting part 11 rises, and the diameter increases from the inner part of the channel inner wall surface 13a having a constant radius to the outer side. The tapered portion 13b is reached. At this time, the pressure of the waste liquid WL that has been flowing through the waste liquid flow path 13 in a high-energy state decreases rapidly, and a strong shearing force is generated in the waste liquid WL. The bubbles in the waste liquid WL are broken up by the shear force, and the contact area between the liquid and the bubbles expands explosively. As a result, the dissolution of the bubbles (oxygen) into the waste liquid WL is accelerated at once.

The above effect allows oxygen to be dissolved in the waste liquid WL without requiring external power, with little energy, and with high dissolution efficiency. Thereby, the waste liquid WL with a high dissolved oxygen content can be stirred and recirculated throughout the storage tank 10.

According to the water quality improvement device of this embodiment, the swirling upward flow and circulating flow with the above-mentioned strong bubbling effect are generated, and physical stimulation is generated in the form of strong vibrations to microorganisms in the water in the storage tank 10. Given. The gas and liquid are adjusted so that the microbial nutrients and the microbial abundance ratio are uniformly dispersed. In addition, the dissolved oxygen rate has been optimized, allowing both aerobic and anaerobic microorganisms to grow together in a well-balanced manner. Thereby, the waste liquid WL in the storage tank 10 can be treated while preventing the generation of scum (floating matter/sediment) and bad odor in the waste liquid WL.

In other words, it is considered that the ultra-high speed upward swirling air sucks up the wastewater from the opening and also causes strong mixing inside the spout pipe 12, contributing to the activation of microorganisms.

Furthermore, since the formation of flocs (bonds) of inorganic suspended matter (metallic substances, clay minerals, etc.) is promoted, the turbidity of the waste liquid WL is improved.

The waste liquid WL in the storage tank 10 is adjusted so that the microbial nutrients and the microbial abundance ratio are uniformly dispersed.

Further, due to the complicated flow of waste liquid WL, the sludge comes into contact with the bubbles (oxygen) carried along the circulating flow, and can be maintained in an oxidation-reduction state in which the production of odor substances such as hydrogen sulfide is difficult to occur.

This provides a strong physical stimulus to the microorganisms present in the waste liquid WL in the storage tank 10, further promoting their proliferation or activation, and promoting the growth of both anaerobic and aerobic microorganisms. It is thought that it will provide water quality improvement that can be maintained by one's own efforts (self-help efforts) as a balanced environment as a suitable coexistence environment.

FIG. 8 is an explanatory diagram showing the activation status of anaerobic and anaerobic microorganisms. When anaerobic and anaerobic microorganisms are not activated, microorganisms a do not take in scum and odor-causing substances b, as shown on the left side of Figure 8, but when anaerobic and anaerobic microorganisms are activated, As shown on the right side of FIG. 8, microorganisms a have taken in scum and odor-causing substances b. Thereby, the microorganism a can decompose the causative substance b and improve the water quality.

On the other hand, when improving water quality, carelessly increasing the dissolved oxygen rate will reduce the habitat of anaerobic bacteria, which are effective in decomposing scum, etc., and the environment will become dominated by aerobic microorganisms, causing anaerobic and aerobic This does not create an environment in which both types of organisms can coexist.

For this reason, air is discharged into the waste liquid WL, and a tornado-shaped water flow is generated in the stagnant waste liquid WL, and the tornado-shaped water flow gives a physical stimulus to the microorganisms, activating them, and causing the microorganisms. It can improve water quality by decomposing scum and odor-causing substances. In addition, this reduces malfunctions and incorrect displays of drainage equipment, and prevents corrosion and deterioration of equipment.

In addition, it can prevent oxygen deficiency accidents during maintenance and the outflow of environmentally harmful substances, and it can be installed easily by simply sinking it into the bottom of the storage tank, which is expected to improve water quality. It is desirable that the need for maintenance such as disassembly and cleaning is small.

By stimulating microorganisms with ultra-high-speed upward jets, it is possible to uniformly disperse wastewater and promote the decomposition of organic matter using powerful circulation flows.

In addition, in the experimental examples described below, a blower that consumes less power under the conditions shown in Table 1 was used compared to a conventional aeration device.

As mentioned above, by repeatedly and strongly applying physical stimulation, it is possible to increase dissolved oxygen in the waste liquid WL, and to coexist not only aerobic microorganisms but also aerobic and anaerobic microorganisms in a well-balanced manner. An example of an experiment in which water quality was improved by activating underwater microorganisms is shown.

We will explain the microbial community structure at the eye level before and after the introduction of the device. Regarding the microbial community structure at the order level, microorganisms of the four orders Clostridiales, Lactobacillales, Bacteroidales, and Enterobacteriales were the main microbial species, and accounted for about 60% to 80% throughout the experimental period. Furthermore, when viewed at the visual level, there is no clear difference in the composition of the community before and after the installation of the device. All of these fourth microbial species were anaerobic microbial species, and anaerobic microbial species were dominant regardless of whether the device was in operation or not.

Next, at the genus level, bacteria in the genus Mitsuokella and the family Veiolellaceae decreased significantly. Coriobacteraceae and Bifidobacterium bacteria also decreased in the other series. Since the common microbial species decreased in both cases, it can be said that these bacteria are the typical bacterial species that are decreased by installing the device. All of these are obligate anaerobic microorganisms, and it is thought that they are species that have lost their activity due to the improved oxygen supply efficiency caused by the device.

On the other hand, the microbial species that increased after the installation of the device will be explained. The genera Novosphingobium, Veionella and Strpetococcus were commonly increasing. Although Novosphingobium bacteria are obligate aerobic bacteria, Streptococcus bacteria are facultative anaerobic bacteria, and Veionella bacteria are obligate anaerobic bacteria, so it was not always the case that only aerobic bacteria were activated.

The amount of oxygen supplied in this experimental apparatus is small compared to the organic load of the influent wastewater, and is much smaller than the amount required to aerobically oxidize all of the organic matter. Therefore, it is clear from the crowd analysis results that the amount of oxygen is not enough to keep the tank in an aerobic state. Therefore, in microbial activation using this device, it is possible to promote the reduction of carbohydrates, which are high-molecular organic substances contained in kitchen wastewater, into low-molecular-weight substances through fermentation, and to use low-molecular-weight organic substances to decompose them at a faster rate than fermentation. It is presumed that microorganisms that perform metabolism through rapid respiration are activated.

Furthermore, it is thought that hydrogen sulfide and the like, which cause bad odors, are generated under strongly reducing conditions. The reduction in malodors is thought to be due to the efficient supply of oxygen, which reduces the number of zones with strongly reducing environments and inactivates malodor-producing microorganisms.

In order to verify the above theory, I conducted a microbial community observation test for water quality improvement and improvement in a kitchen wastewater tank at an airport with Associate Professor Kurisu Futa of the Water Environmental Engineering Research Center, Graduate School of Engineering, the University of Tokyo.

As a result of the test, it was confirmed that the contents of BOD, hexane extract, SS, and sulfide ions in the drainage tank were reduced.

Here, each numerical value of BOD, hexane extract, SS, and sulfide ion is the following index.
``BOD'': An indicator that quantifies water quality and represents pollution. This is the amount of oxygen consumed by microorganisms during the oxidation and decomposition of organic matter in water over a certain period of time, and the higher the number, the worse the water quality.
``Hexane extract'': A value that mainly represents the amount of oil content.
"SS": Represents the number of insoluble particles of 2 or less suspended in water.
"Sulfide ion": A substance that generates hydrogen sulfide under certain conditions; the higher the value, the easier it is to generate hydrogen sulfide.
``Hydrogen sulfide'': A highly lethal gas that causes a strong odor similar to that of rotten eggs in wastewater.

The water quality improvement device of this embodiment uses a powerful bubbling section to repeatedly and strongly apply physical stimulation when treating waste liquid in a storage tank, thereby increasing dissolved oxygen in the waste liquid in the tank, and using only aerobic microorganisms. By allowing both aerobic and anaerobic microorganisms to grow together in a well-balanced manner, water quality can be improved by activating aquatic microorganisms.

For all types of water treatment facilities, such as storage tanks and kitchen wastewater receiving tanks, improving water quality in building pits and combined septic tanks, algae control measures in dams, preventing spoilage of cooling water in factories, reducing suspended solids in sewage treatment plants, and stirring bioreactors. It can be applied, for example, to oil processing in Chinese restaurants and restaurants, and other biochemical fields. It can also be used as a liquid fertilizer in agriculture by activating microorganisms in the soil.

WL Waste liquid A, B Swirling upward flow C, D Circulating flow 10 Storage tank 10a Side part 10b Bottom part 10c Top part 11 Spout part 12 Spout pipe 12a Spout pipe main body 12b Gas flow path 12bx First gas flow path 12by Second gas flow Channel 12c Flange portion 12d Bolt 121bx First discharge port 121by Second discharge port 13 Waste liquid flow path 13a Channel inner wall surface 13b Tapered portion 14 Air supply portion 14a Air chamber main body 14b Air chamber 14c Vent port 14d Supply port 15 Air introduction portion 15a Pump 15b Air inlet 15c Air passage 16 Inflow pipe 17 Drain pipe 18 Fixing base 18a Base material 18b Legs

Claims (4)

A water quality improvement device that improves the water quality of the waste liquid by circulating the waste liquid containing microorganisms stored in the storage tank in the storage tank and activating the microorganisms,
A cylindrical shape having a waste liquid flow path that takes in the waste liquid from the bottom side and discharges it from the top side, and a gas flow path that communicates with the waste liquid flow path and releases air into the waste liquid flow path. a spout pipe,
an air supply unit having an air chamber that stores air introduced from outside the storage tank and is provided with a supply port that communicates with the gas flow path and supplies the stored air to the gas flow path;
an air introduction part provided outside the storage tank and introducing air into the air chamber,
The gas flow path has a first gas flow path provided in communication with the waste liquid flow path, and a distance from the bottom surface of the jet pipe is different from the first gas flow path, and the gas flow path has a first gas flow path provided in communication with the waste liquid flow path. a second gas flow path having a second discharge port provided in communication with the flow path ;
The difference in distance between the first discharge port and the second discharge port from the bottom surface of the jet pipe is 5 mm or more and 10 mm or less.
Water quality improvement equipment. The air discharged from the first discharge port and the second discharge port respectively swirls upward along a spiral trajectory, and the air and the waste liquid generate a swirling upward flow in which a gas-liquid mixture is formed. The water quality improvement device described. A water quality improvement method for improving the water quality of the waste liquid by circulating the waste liquid containing microorganisms stored in the storage tank in the storage tank and activating the microorganisms, the method comprising:
A cylindrical ejection pipe having a waste liquid flow path, a first gas flow path having a first discharge port provided in communication with the waste liquid flow path, and a distance from the bottom of the ejection pipe to the first gas flow path. In the spouting pipe, the spouting pipe is provided with a gas flow path including a second gas flow path having a second gas flow path that is different from the first discharge port and is provided in communication with the waste liquid flow path. a step of taking in from the bottom side of the pipe and discharging from the top side of the spouting pipe;
Introducing air from outside the storage tank into an air chamber that stores air introduced from outside the storage tank and is provided with an inlet that communicates with the gas flow path and through which the stored air is sent. and simultaneously performing the step of releasing air from the first discharge port and the second discharge port to circulate the waste liquid within the storage tank ,
A difference in distance between the first discharge port and the second discharge port from the bottom surface of the jet pipe is set to 5 mm or more and 10 mm or less.
How to improve water quality. According to claim 3 , the air discharged from the first discharge port and the second discharge port swirls upward along respective spiral trajectories, and the air and the waste liquid generate a swirling upward flow in which gas and liquid are mixed. How to improve water quality.

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