JP6983695B2 - Wastewater treatment method and wastewater treatment system - Google Patents

Description

The present invention relates to a method for treating wastewater and the like.

Traditionally, large amounts of antibiotics have been used in various industries. For example, in the livestock industry, it is common to administer antibiotics to livestock to prevent infection. Antibiotics remain in manure excreted from livestock treated with antibiotics, and therefore antibiotics also remain in wastewater (eg, livestock wastewater).

Japanese Unexamined Patent Publication No. 2003-940909 Japanese Unexamined Patent Publication No. 2014-138923 Japanese Unexamined Patent Publication No. 2009-183906 Japanese Unexamined Patent Publication No. 2017-023918

If wastewater containing an antibiotic is discharged into a river as it is, bacteria resistant to the antibiotic (drug-resistant bacteria) may be generated at the discharge point or downstream thereof. When drug-resistant bacteria occur in rivers, drug-resistant bacteria spread from river water to soil and the like. Drug-resistant bacteria that have spread into the environment such as soil can infect humans and animals through water and soil. When humans and animals are infected with drug-resistant bacteria, treatment becomes very difficult because existing antibiotics are difficult or completely ineffective against drug-resistant bacteria. Thus, the direct discharge of wastewater containing antibiotics into rivers can result in increased human and animal health risks.

There are various conventional methods for removing antibiotics. For example, PES membranes, ceramic membrane filters, and synthetic adsorbents capable of separating antibiotics have been commercialized. Further, Patent Document 2 discloses a method of adsorbing an antibiotic on an adsorbent. Further, Patent Document 3 discloses a method for removing an antibiotic in a effluent by magnetic separation. Further, Patent Document 4 discloses a method for removing an antibiotic by adding a flocculant to wastewater.

Further, Patent Document 1 discloses a technique for decomposing and detoxifying an antibiotic in pig urine by a microorganism activated by showering and aeration.

However, the technique described in Patent Document 1 can decompose a wide variety of antibiotics only within a range that can be decomposed by microorganisms. Further, the above-mentioned product for removing antibiotics and the technique described in Patent Document 2 have not been developed for treating wastewater (for example, livestock wastewater). In other words, in the current wastewater treatment, a process for discharging residual antibiotics in the wastewater to the extent that there is no problem has not yet been established.

One aspect of the present invention has been made in view of the above problems, and an object of the present invention is to realize a wastewater treatment method or the like capable of removing an antibiotic from wastewater.

In order to solve the above-mentioned problems, the wastewater treatment method according to one aspect of the present invention is characterized by including a heating step of decomposing an antibiotic contained in the wastewater by heating the wastewater.

According to the above method, the antibiotics remaining in the wastewater (for example, wastewater derived from livestock manure and / or livestock urine generated from the barn) can be decomposed and then the wastewater can be discharged. That is, antibiotics can be removed from the wastewater.

In the heating step of the wastewater treatment method, the wastewater may be heated at a temperature of 38 ° C. or higher and 80 ° C. or lower.

Since the wastewater contains various organic substances other than antibiotics, it is preferable to decompose the organic substances in the wastewater by using microorganisms before draining into the environment. According to the above method, the antibiotics in the wastewater can be decomposed at a heating temperature that minimizes adverse effects on microorganisms. In addition, since it is heated at a relatively low temperature, it is possible to decompose antibiotics in wastewater in a simple facility and at low cost by reducing the fuel cost at the time of heating.

The wastewater treatment method includes an adsorption step of adsorbing at least one of the antibiotic and a decomposition product of the antibiotic to the adsorbent by bringing the wastewater into contact with the adsorbent, and the adsorption step includes the adsorbent. It may be carried out at least one before and after the heating step.

According to the above method, the antibiotic or the decomposition product of the antibiotic can be removed from the wastewater. The adsorption step is particularly effective in removing antibiotics that are difficult to decompose by heat. By combining this adsorption step and the heating step, antibiotics can be more reliably removed from the wastewater.

In the wastewater treatment method, the wastewater may be livestock wastewater.

According to the above method, among various wastewaters that can be treated by this wastewater treatment method, livestock wastewater can be treated in particular.

In the wastewater treatment method, the adsorbent may be a carbide of livestock manure.

According to the above method, the procurement cost of the adsorbent can be reduced as compared with the case where activated carbon or the like is used as the adsorbent. In addition, wastewater (for example, livestock wastewater) and livestock manure are often treated in parallel in the same facility. Therefore, it is possible to efficiently circulate the cycle consisting of the production of the animal manure carbide capable of adsorbing the antibiotic and the regeneration of the animal manure carbide adsorbed with the antibiotic. Further, there is an advantage that it is easy to secure an inventory of the adsorbent.

In the wastewater treatment method, in the heating step, the waste heat generated when treating the livestock manure may be used as at least a part of the heat source for heating the wastewater.

The livestock manure can be processed as compost or as a livestock manure carbide for fertilizer or adsorbent by being subjected to a predetermined treatment. According to the above method, by using the waste heat generated when treating the livestock manure for the heat treatment of the wastewater, it is possible to reduce the fuel in the heating step and the preparation and operation cost of the heating equipment.

In order to solve the above-mentioned problems, the wastewater treatment system according to one aspect of the present invention includes a heating tank that accommodates wastewater and decomposes antibiotics contained in the wastewater by heating the wastewater. It is characterized by that.

According to the wastewater treatment system described above, the antibiotics remaining in the wastewater (for example, the wastewater generated from the barn and / or the wastewater derived from the wastewater, and the water used for cleaning the wastewater and / or the animal urine) are heated. The wastewater can be discharged after being thermally decomposed in the tank. That is, antibiotics can be removed from the wastewater.

The wastewater treatment system may include an adsorption tower that adsorbs the antibiotic and at least one of the decomposition products of the antibiotic to the adsorbent by contacting the wastewater with the adsorbent.

According to the wastewater treatment system described above, antibiotics or decomposition products of antibiotics can be removed from wastewater in the adsorption tower. The adsorption tower is particularly effective in removing antibiotics that are difficult to decompose by heat. By combining this adsorption tower with a heating tank, antibiotics can be more reliably removed from the wastewater.

In the wastewater treatment system, the heating tank may utilize the waste heat generated when treating livestock manure as at least a part of the heat source for heating the wastewater.

According to the above-mentioned wastewater treatment system, livestock manure can be processed as compost or as livestock manure carbide for fertilizer or adsorbent by being subjected to a predetermined treatment. According to the above-mentioned wastewater treatment system, by using the waste heat generated when treating the livestock manure for the heat treatment of the wastewater, it is possible to reduce the preparation and operation cost of the fuel in the heating tank and the heating equipment.

In the wastewater treatment system, the wastewater may be livestock wastewater.

According to the above method, among various wastewaters that can be treated by this wastewater treatment system, livestock wastewater can be treated in particular.

According to one aspect of the present invention, antibiotics can be removed from wastewater. More specifically, according to one aspect of the present invention, wastewater can be treated so as not to pollute the environment even if it is released into the environment (for example, a river or the like).

It is a figure which shows a typical example of the wastewater treatment system which concerns on Embodiment 1 of this invention. It is a figure which shows a typical example of the wastewater treatment system which concerns on Embodiment 2 of this invention. It is a figure which shows the time-dependent change of the antibiotic concentration in a solution by thermal decomposition. It is a graph which shows the measurement result of the specific surface area of the poultry manure carbide. It is a graph which shows the result of the MB adsorption performance test of the carbide of chicken manure.

The wastewater treatment method according to the present invention is a method for treating arbitrary wastewater in a state where it can be discharged into a river or the like. The wastewater treatment method according to the present invention is, for example, a method for removing an antibiotic contained in livestock wastewater. The wastewater treatment method according to the present invention can treat any wastewater, and the type of the wastewater is not particularly limited. Examples of the wastewater include liquid components of livestock manure and livestock urine (livestock wastewater), factory wastewater, and domestic wastewater.
Hereinafter, the wastewater treatment system according to the embodiment of the present invention will be described by taking livestock wastewater as an example.

[Embodiment 1]
FIG. 1 is a diagram showing a typical example of the wastewater treatment system 100 according to the present embodiment. The wastewater treatment system 100 includes at least an apparatus for performing a heating step (described later). In the illustrated example, the wastewater treatment system 100 includes a solid-liquid separation unit 10, a solid matter treatment unit 20, a decomposition treatment unit 30, a membrane separation tank 40, and a disinfection tank 50.

The undiluted solution of wastewater (for example, livestock manure and livestock urine discharged from a ranch or the like) is separated into water and solid by a predetermined method. Since the wastewater treatment system 100 may also include the solid matter treatment unit 20, it is also possible to treat the separated solids. The wastewater treatment system 100 treats the water (separated water) separated from the undiluted solution of wastewater (for example, livestock manure and livestock urine) as wastewater (for example, livestock wastewater). Since the wastewater contains minute solids, the wastewater treatment system 100 first performs a treatment for removing the minute solids.

(Solid-liquid separation unit 10)
The solid-liquid separation unit 10 is a group of devices for separating wastewater into a solid and a liquid. The solid-liquid separation unit 10 includes a raw water tank 1, a solid-liquid separator 2, a first flow rate adjusting tank 3, a second flow rate adjusting tank 4, a sludge storage tank 5, and a sludge dehydrator 6. Each device included in the solid-liquid separation unit 10 may be provided in the same facility or may be provided in a distant place. The same applies to each device included in the decomposition processing unit 30 described later.

The raw water tank 1 is a tank for storing wastewater. The raw water tank 1 may be any tank that can store wastewater, and its shape, volume, and the like are not particularly limited. The wastewater stored in the raw water tank 1 is appropriately sent to the solid-liquid separator 2.

The solid-liquid separator 2 is a device that separates wastewater into a solid and a liquid. The specific configuration of the solid-liquid separator 2 is not particularly limited, and may be, for example, a centrifuge, a filter, or the like. The solid (sludge) generated after the treatment of the solid-liquid separator 2 is sent to the solid matter processing unit 20, and the liquid is sent to the first flow rate adjusting tank 3.

The first flow rate adjusting tank 3 is a tank that adjusts the amount of liquid flowing into the second flow rate adjusting tank 4. The first flow rate adjusting tank 3 treats the liquid flowing in from the solid-liquid separator 2 (for example, recovering the solid (sludge) remaining in the liquid), and adjusts the flow rate of the treated liquid (treated water). While adjusting, it is appropriately sent to the second flow rate adjusting tank 4. Further, the first flow rate adjusting tank 3 sends the solid (sludge) remaining after the treatment to the sludge storage tank 5. The first flow rate adjusting tank 3 may be any tank as long as it can adjust the amount of liquid flowing into the second flow rate adjusting tank 4, and its shape, volume, and the like are not particularly limited. Further, the first flow rate adjusting tank 3 may include a valve for adjusting the inflow amount of the liquid into the second flow rate adjusting tank 4.

The sludge storage tank 5 is a tank for storing sludge. The sludge storage tank 5 may be any tank that can store sludge, and its shape, volume, and the like are not particularly limited. The sludge storage tank 5 sends sludge to the sludge dehydrator 6 as appropriate. The sludge dehydrator 6 is a device for dehydrating sludge. The solid separated by dehydration is sent to the solid matter processing unit 20. On the other hand, the liquid separated by dehydration is sent to the second flow rate adjusting tank 4. The specific configuration of the sludge dehydrator 6 is not particularly limited, and may be, for example, a centrifuge, a filter, or the like.

The second flow rate adjusting tank 4 is a tank that adjusts the flow rate of the liquid to the first aeration tank 31 of the decomposition processing unit 30. The second flow rate adjusting tank 4 stores the liquid flowing in from the first flow rate adjusting tank 3 and the liquid flowing in from the sludge dehydrator 6. The second flow rate adjusting tank 4 sends the stored liquid to the first aeration tank 31 of the decomposition processing unit 30 while adjusting the flow rate. The second flow rate adjusting tank 4 may be any tank as long as it can adjust the amount of liquid flowing into the first aeration tank 31, and its shape, volume, and the like are not particularly limited. Further, the second flow rate adjusting tank 4 may include a valve for adjusting the inflow amount of the liquid into the first aeration tank 31.

(Solid matter processing unit 20)
The solid matter processing unit 20 is a device or a group of devices for treating sludge sent from the solid-liquid separator 2 and the sludge dehydrator 6. The solid matter processing unit 20 may treat not only sludge but also livestock manure itself (for example, livestock manure itself after removing wastewater). Examples of the solid matter processing unit 20 include a livestock manure charcoal production facility, a livestock manure composting facility, and an incinerator facility for livestock manure, sludge, or livestock manure charcoal (for example, livestock manure charcoal having adsorbed antibiotics and the like). .. Hereinafter, sludge generated from the separated water is also treated as a part of livestock manure. That is, in the following description, "livestock manure" means livestock manure and sludge.

The livestock manure charcoal production facility is a facility for producing livestock manure charcoal by heating livestock manure and sludge at a predetermined temperature to carbonize them. Carbide from livestock manure can be used as an organic fertilizer or an adsorbent. In the livestock manure carbide production facility, waste heat is generated when the livestock manure and sludge are heated at a predetermined temperature, and the waste heat can be used in the heating tank 33 described later.

The composting facility is a facility for converting livestock manure into compost (organic fertilizer) by aerobic fermentation. In the composting facility, fermentation heat is generated during aerobic fermentation, and the fermentation heat can be used in the heating tank 33 described later.

The incineration facility incinerates livestock manure (for example, livestock manure such as chicken manure), sludge or livestock manure charcoal (for example, livestock manure charcoal having adsorbed antibiotics) and converts them into incineration ash (organic fertilizer). It is a facility of. In the incinerator facility, incinerator heat is generated, and the incinerator heat can be used in the heating tank 33 described later.

Steam is generated using the waste heat generated at the livestock manure charcoal production facility, the fermentation heat generated at the composting facility, and the incineration heat generated at the incinerator facility, and the turbine is rotated by the steam. This also makes it possible to extract electrical energy. That is, the wastewater treatment system 100 may include a private power generation unit (not shown) including a steam generating unit that generates steam using waste heat, fermentation heat, or incineration heat, and a turbine. .. With this configuration, the electric energy required for the operation of the wastewater treatment system 100 can be generated in-house.

As described above, the livestock manure, sludge, and livestock manure carbide are converted into useful substances and electric energy by passing through the solid matter processing unit 20, and the treatment is completed.

(Disassembly processing unit 30)
On the other hand, the water content of the wastewater is sent to the decomposition treatment unit 30 via the solid-liquid separation unit 10 and the treatment is continued. The decomposition treatment unit 30 is a group of devices for decomposing organic substances and antibiotics contained in the liquid flowing in from the second flow rate adjusting tank 4 (that is, the liquid from which the solid component is removed from the waste water). The decomposition treatment unit 30 executes the decomposition treatment of the antibiotic at least in the heating tank 33 (described later).

Here, the antibiotic to be decomposed in the wastewater treatment system 100 may be any antibiotic capable of thermal decomposition.

In the present embodiment, the decomposition treatment unit 30 describes a case where the decomposition treatment of the organic substance by the activated sludge method and the decomposition treatment of the antibiotic are executed. The activated sludge method is a method of aerating (and heating) wastewater in an aeration tank to decompose organic substances contained in the wastewater into aerobic microorganisms.

The decomposition treatment unit 30 includes a first aeration tank 31, a second aeration tank 32, and a heating tank 33. In the illustrated example, there are two aeration tanks, but the aeration tank of the wastewater treatment system 100 may be one or three or more. Further, when the organic matter is not decomposed, it is not necessary to provide an aeration tank.

The first aeration tank 31 and the second aeration tank 32 are tanks for decomposing the wastewater flowing from the solid-liquid separation unit 10 by the decomposing action of aerobic microorganisms. Different types of aerobic microorganisms are put into the wastewater into the first aeration tank 31 and the second aeration tank 32. After charging the aerobic microorganisms, the first aeration tank 31 and the second aeration tank 32 are aerated for a predetermined number of days.

The decomposition treatment unit 30 may adopt a method other than the activated sludge method for the decomposition treatment of organic substances other than antibiotics. For example, the decomposition treatment unit 30 may execute one or more of aerobic treatment (nitrification), anaerobic treatment (denitrification), and methane fermentation (anaerobic treatment) in combination with the decomposition treatment of an antibiotic. good. That is, the decomposition treatment unit 30 may include an aerobic treatment tank, an anaerobic treatment tank, or a methane fermentation tank (not shown) instead of the first aeration tank 31 and the second aeration tank 32. Of course, the decomposition treatment unit 30 may include an aerobic treatment tank, an anaerobic treatment tank, or a methane fermentation tank and an aeration tank.

The heating tank 33 is a tank for executing a heating step of decomposing the antibiotics contained in the wastewater by accommodating and heating the wastewater. The decomposition product of the antibiotic generated by thermal decomposition (hereinafter, simply referred to as “decomposition product”) may be further decomposed by the microorganisms administered in the first aeration tank 31 and the second aeration tank 32.

That is, the decomposition treatment unit 30 may include a pipe connecting the heating tank 33 and at least one of the first aeration tank 31 and the second aeration tank 32. Then, the drainage after heating (if necessary, cooled after heating) may be returned from the heating tank 33 to at least one of the first aeration tank 31 and the second aeration tank 32 through the pipe. Alternatively, in the wastewater treatment system 100, at least one of the first aeration tank 31 and the second aeration tank 32 may be provided downstream of the heating tank 33.

The wastewater stored in the heating tank 33 is heated to a predetermined temperature by a heat source provided inside or outside the heating tank 33.

The specific method for heating the heating tank 33 is not particularly limited. For example, the heating tank 33 may be directly heated while stirring the wastewater contained in the heating tank 33. Further, for example, a metal pipe through which a heat conductor (air, oil, water, etc.) containing heat from a heat source passes may be brought into contact with the surface of the heating tank 33 or drawn into the inside. As a result, the heat of the heat conductor can be transferred to the wastewater via the metal pipe.

In the heating step performed by the heating tank 33, the waste heat generated when treating the livestock manure may be used as at least a part of the heat source for heating the wastewater.

For example, when composting livestock manure in the solid matter processing unit 20, the fermentation heat generated in the composting process may be used as a heat source for heating the wastewater in the heating step. Further, when incinerating livestock manure in the solid matter processing unit 20, the incinerator heat generated by the incinerator may be used as a heat source for heating the wastewater. Further, when the solid matter processing unit 20 produces carbides of livestock manure, the waste heat when the livestock manure is heated may be used as a heat source for heating the wastewater.

Furthermore, as a heat source in the heating process, at least one of these waste heats generated when treating livestock manure and heat generated in a dedicated facility (boiler, etc.) for heating wastewater are used in combination. You may.

Further, in the heating step performed by the heating tank 33, waste heat and residual heat from a plant such as a waste incinerator, a sludge incinerator, a power plant or an industrial device are used as at least a part of a heat source for heating wastewater. You may use it. Further, in the heating step performed by the heating tank 33, heat directly obtained from an external fuel (for example, fossil fuel) may be used as at least a part of a heat source for heating the wastewater. That is, in the heating step executed by the heating tank 33, heat is obtained from the fuel in a dedicated facility without utilizing waste heat and residual heat, and the heat is used as at least a part of a heat source for heating the wastewater. May be good.

(Heating temperature in the heating process)
The temperature of wastewater (heating temperature) in the heating process of the heating tank 33 includes the amount of wastewater stored, the type of antibiotic to be decomposed, the concentration of antibiotics allowed to remain in the wastewater (target water quality concentration), and Etc., it may be appropriately determined.

For example, it is desirable that the heating tank 33 is heated so that the temperature of the drainage is stable at least 35 ° C. or higher during a predetermined heating period. In other words, it is desirable that the heating temperature in the heating tank 33 is 35 ° C. or higher.

From the viewpoint of the growth environment of microorganisms, the temperature of the wastewater in the first aeration tank 31 and the second aeration tank 32 is about 35 ° C. at the maximum, and the maximum temperature is not stably maintained. Therefore, even if the temperature of the drainage in the first aeration tank 31 and the second aeration tank 32 exceeds the temperature at which the antibiotic can be thermally decomposed, it is not stable and the first aeration tank 31 and the second aeration tank 32 are not stable. It is difficult to reduce the concentration of antibiotics in the wastewater to the extent that there is no problem even if it is discharged into the river by 32 alone.

Therefore, by heating the wastewater to 35 ° C. or higher in the heating step, the temperature of the wastewater can be stably maintained at a temperature at which the antibiotic can be thermally decomposed, and thus the concentration of the antibiotic in the wastewater is surely lowered. be able to.

The maximum value of the heating temperature of the wastewater in the heating tank 33 is not particularly limited, but is preferably 80 ° C. or lower, for example. This is because equipment such as pipes and pumps in a general wastewater treatment facility (for example, a livestock wastewater treatment facility) may not be able to withstand a high temperature of 80 ° C. or higher. Further, as the heating temperature of the wastewater becomes higher, it becomes difficult to heat the wastewater by using only the waste heat, and the fuel cost of the heat source increases. As described above, the heating limit temperature considered from the equipment aspect of the wastewater treatment system 100 may be the maximum value of the heating temperature of the wastewater.

Furthermore, in the heating tank 33, it is desirable to heat the drainage so that the temperature of the drainage is 38 ° C. or higher and 60 ° C. or lower. At the heating temperature, the antibiotics in the wastewater can be reliably decomposed while suppressing the adverse effect on the microorganisms as much as possible, as compared with the case of heating at a temperature higher than 60 ° C. and 80 ° C. or lower. In addition, the antibiotics in the wastewater can be decomposed in a simple facility as compared with the case of heating at a temperature higher than 60 ° C and at 80 ° C or lower. In this case, the fuel cost at the time of heating can also be suppressed.

Furthermore, in the heating tank 33, it is most desirable to heat the drainage so that the temperature of the drainage is 38 ° C. or higher and 55 ° C. or lower. In order to reduce the concentration of organic matter in wastewater, it is desirable to decompose organic matter by microorganisms for as long as possible. Further, it is desirable that the organic substances generated when the antibiotic is thermally decomposed in the heating tank 33 are further decomposed by microorganisms (microorganisms introduced in the first aeration tank 31 and the second aeration tank 32). Further, as will be described in detail later, the heating step may be executed in the first aeration tank 31 or the second aeration tank 32.

Therefore, if the heating temperature of the wastewater is too high, the activity of microorganisms may decrease. On the other hand, by setting the heating temperature to 38 ° C. or higher and 55 ° C. or lower, the antibiotics in the wastewater can be decomposed at a heating temperature that minimizes adverse effects on microorganisms. Therefore, it is possible to achieve both the decomposition of organic substances by microorganisms and the decomposition of antibiotics by heating. In addition, since the wastewater is heated at a relatively low temperature of 55 ° C at the maximum, it is possible to decompose the antibiotics in the wastewater in a simple facility and at low cost by reducing the fuel cost at the time of heating. ..

In addition, the microorganisms to be added to at least one of the first aeration tank 31 and the second aeration tank 32 may be subjected to a preliminary acclimatization treatment (treatment for adapting the microorganisms to a certain environment). This may allow the growth of heat-tolerant microorganisms. Then, by changing the microorganisms to be added to at least one of the first aeration tank 31 and the second aeration tank 32 to the microorganisms having the above heat resistance, the decrease in the activity of the microorganisms, which is a demerit when heating the wastewater, is suppressed. be able to.

When the decomposition treatment unit 30 employs an anaerobic treatment such as denitrification instead of the activated sludge method, it is desirable to heat the wastewater in the heating tank 33 so that the temperature of the wastewater is 40 ° C. or higher. When an anaerobic treatment such as denitrification is adopted in the decomposition treatment unit 30, the anaerobic treatment tank is generally operated at about 37 ° C. at which the microbial activity is maximized, and it is usually unlikely that the temperature exceeds 40 ° C. .. Therefore, by setting the temperature of the wastewater in the heating tank 33 to 40 ° C. or higher, antibiotics that cannot be decomposed by the temperature of the wastewater in the anaerobic treatment tank can be thermally decomposed.

Further, when methane fermentation is adopted instead of the activated sludge method in the decomposition treatment unit 30, when the methane fermentation is a medium temperature fermentation method, the wastewater is heated to a temperature of 37 ° C. or higher and 80 ° C. or lower in the heating tank 33. Is desirable. When the methane fermentation is a high temperature fermentation method, it is desirable to heat the wastewater to a temperature of 55 ° C. or higher and 80 ° C. or lower in the heating tank 33.

The reason why it is desirable that the temperature of the drainage in the heating tank 33 is 80 ° C. or lower is the same as in the case of the activated sludge method. When the methane fermentation is a medium temperature fermentation method, the methane fermentation tank is generally operated at about 37 ° C. When the methane fermentation is a high temperature fermentation method, the methane fermentation tank is operated at about 55 ° C. Therefore, by keeping the temperature of the wastewater at 37 ° C. or higher (in the case of the medium-temperature fermentation method) or 55 ° C. or higher (in the case of the high-temperature fermentation method) in the heating tank 33, the antibiotics that cannot be decomposed by the temperature of the wastewater in the methane fermentation tank are heated. Can be disassembled.

(Heating period in the heating process)
The heating period in the heating tank 33 may be appropriately determined according to the amount of wastewater to be stored, the type of antibiotic to be decomposed, the target water quality concentration, and the like. For example, the heating period in the heating tank 33 is preferably 1 hour or longer, 2 hours or longer, 3 hours or longer, 4 hours or longer, 5 hours or longer, or 6 hours or longer. Further, the wastewater may be stored in the heating tank 33 and the heating may be continued for as long as possible within the range where the treatment of the entire wastewater treatment system 100 is not delayed.

If the antibiotic concentration in the wastewater does not reach the target water quality value even after the predetermined heating period has elapsed, between the decomposition treatment unit 30 and the membrane separation tank 40, or between the membrane separation tank 40 and the disinfection tank 50. A heating tank 33 (or a decomposition treatment unit 30) may be further provided in the heating tank 33 (or the decomposition treatment unit 30) to perform heating. In addition, when actually operating a wastewater treatment facility (for example, a livestock wastewater treatment facility), the residence time of wastewater in each tank should be secured longer than the residence time calculated in the equipment design of each tank. There are many. In this way, if the residence time in each tank can be adjusted, the residence time of the wastewater in the heating tank 33 may be set longer than usual, and heating may be continued until the target water quality value is reached.

Usually, in the livestock industry, livestock are given multiple types of antibiotics. Therefore, it is common that a plurality of types of antibiotics remain in the wastewater from livestock, especially in the wastewater. Therefore, the above-mentioned heating temperature and heating period may be set so that the concentration of the antibiotic that is most difficult to be pyrolyzed in the wastewater stored in the heating tank 33 is equal to or less than the target water quality concentration for the antibiotic. desirable.

(Membrane Separation Tank 40)
The membrane separation tank 40 is a tank for further separating the wastewater flowing from the decomposition treatment unit 30 into a solid and a liquid. A membrane filter is provided inside the membrane separation tank 40, and wastewater is separated into a solid and a liquid by passing through the filter. The separated liquid is sent to the disinfection tank 50, and the solid is returned to the sludge storage tank 5.

(Disinfection tank 50)
The disinfection tank 50 is a tank for disinfecting the wastewater flowing from the membrane separation tank 40. In the disinfection tank 50, the disinfectant is administered after the wastewater is stored to some extent. This disinfectant is a drug for sterilizing microorganisms administered in the first aeration tank 31 and the second aeration tank 32, and Escherichia coli originally contained in the waste water. The wastewater sterilized in the disinfection tank 50 is discharged to the river or the like after being inspected for water quality that can be discharged to the river or the like.

(Modification example)
The wastewater treatment system 100 may be provided with the heating tank 33 at a position other than the position shown in FIG. For example, in the wastewater treatment system 100, the heating tank 33 may be provided between the second flow rate adjusting tank 4 and the first aeration tank 31. In this case, the wastewater heat-treated in the heating tank 33 is cooled to a temperature at which the microbial activity in the subsequent first aeration tank 31 is not impaired, and then sent to the first aeration tank 31. Thereby, in the heating tank 33, the heating temperature can be set without worrying about the decrease in the activity of microorganisms. Further, since the decomposition product of the antibiotic can be further decomposed in the first aeration tank 31 and the second aeration tank 32, the water quality of the wastewater discharged from the decomposition treatment unit 30 can be further improved.

Further, for example, in the wastewater treatment system 100, the heating tank 33 may be provided between the membrane separation tank 40 and the disinfection tank 50. In this case as well, the heating temperature can be set without worrying about a decrease in the activity of microorganisms. Further, since the sludge is further separated from the wastewater in the membrane separation tank 40, the residual antibiotic can be thermally decomposed after the antibiotic adhering to the sludge is physically removed.

Further, for example, in the wastewater treatment system 100, the heating tank 33 may be provided between the first aeration tank 31 and the second aeration tank 32. In this case, in the second aeration tank 32, it is desirable to administer a microorganism capable of further decomposing the decomposed product into a harmless organic substance or an inorganic substance. As a result, the antibiotic can be decomposed in two stages of thermal decomposition and decomposition by microorganisms, so that the water quality of the wastewater discharged from the decomposition treatment unit 30 can be further improved.

Further, the heating step may be performed in the first aeration tank 31 or the second aeration tank 32 (or an aerobic treatment tank, an anaerobic treatment tank, or a methane fermentation tank). In other words, the first aeration tank 31 or the second aeration tank 32 (or an aerobic treatment tank, an anaerobic treatment tank, or a methane fermentation tank) may also have the function of the heating tank 33. Further, the wastewater treatment system 100 may not execute the heating step in the heating tank 33 (or may not include the heating tank 33), and may execute the heating step in another device. For example, the heating step may be executed in the first flow rate adjusting tank 3, the second flow rate adjusting tank 4, the membrane separation tank 40, or the like.

Further, the wastewater treatment system 100 executes the heating step in the heating tank 33, and also performs the first flow adjustment tank 3, the second flow adjustment tank 4, the first aeration tank 31, and the second aeration tank 32 (or aerobic treatment). The heating step may be performed in a tank, an anaerobic treatment tank, or a methane fermentation tank), a membrane separation tank 40, or the like.

According to the wastewater treatment system 100 described above, the antibiotics remaining in the wastewater can be thermally decomposed and then the wastewater can be discharged to a river or the like. Therefore, it is possible to prevent the outbreak of antibiotic-resistant bacteria in the river or the like where the wastewater is discharged.

[Embodiment 2]
The wastewater treatment system according to the present invention may include an adsorption step of adsorbing at least one of the antibiotic and the decomposition product of the antibiotic to the adsorbent by bringing the wastewater into contact with the adsorbent. Then, the adsorption step may be carried out at least one before and after the heating step. Hereinafter, a second embodiment of the present invention will be described. For convenience of explanation, the same reference numerals are given to the members having the same functions as the members described in the above-described embodiment, and the description thereof will not be repeated.

FIG. 2 is a diagram showing a typical example of the wastewater treatment system 200 according to the second embodiment. The wastewater treatment system 200 is different from the wastewater treatment system 100 according to the first embodiment in that it includes a suction tower 60.

(Adsorption tower 60)
The adsorption tower 60 is a tank for executing a step (adsorption step) of adsorbing at least one of an antibiotic and a decomposition product of the antibiotic to the adsorbent by bringing the wastewater into contact with the adsorbent. The adsorption step may be performed at least one before and after the heating step. Therefore, the adsorption tower 60 may be installed at least one place before and after the heating tank 33. In the present embodiment, as shown in FIG. 2, a case where the adsorption tower 60 is provided after the disinfection tank 50 will be described.

The specific method of the adsorption step in the adsorption tower 60 is not particularly limited. For example, by arranging a column filled with an adsorbent inside the adsorption tower 60 and allowing drainage to pass through the column, the adsorbent adsorbs at least one of an antibiotic and a decomposition product of the antibiotic. May be good. Alternatively, a membrane-like adsorbent may be arranged in the adsorption tower 60, and drainage may be allowed to pass through the membrane. The adsorbent can be replaced with a new adsorbent as appropriate when its adsorption performance deteriorates.

The adsorption tower 60 may be an adsorption tank filled or arranged with an adsorbent. Then, by storing the wastewater in the adsorption tank for a predetermined period of time, the adsorbent may adsorb at least one of the antibiotic and the decomposition product of the antibiotic. Furthermore, after a predetermined period has elapsed, the water quality of the wastewater in the adsorption tower 60 may be inspected, and then the wastewater in the adsorption tower 60 may be discharged to a river or the like.

Further, the material of the adsorbent is not particularly limited. For example, a porous material such as activated carbon may be used as the adsorbent. However, it is desirable that the adsorption tower 60 of the wastewater treatment system 200 uses carbides of livestock manure as an adsorbent.

When the carbide of livestock manure is used as an adsorbent, the procurement cost of the adsorbent can be reduced as compared with the case of using activated carbon or the like as an adsorbent. In addition, wastewater (for example, livestock wastewater) and livestock manure are often treated in parallel in the same facility. Therefore, it is possible to efficiently circulate the cycle consisting of the production of the animal manure carbide capable of adsorbing the antibiotic and the regeneration of the animal manure carbide adsorbed with the antibiotic. Further, there is an advantage that it is easy to secure an inventory of the adsorbent.

The carbide of livestock manure used as an adsorbent in the adsorption tower 60 may be the charcoal of livestock manure produced in the solid matter processing unit 20, or the charcoal of livestock manure produced separately from the series of treatments of the wastewater treatment system 200. There may be.

By the way, when the carbide of livestock manure used as an adsorbent (hereinafter, simply referred to as charcoal of livestock manure) is brought into contact with wastewater, organic substances (phosphorus, nitrogen, etc.) may be eluted from the charcoal of livestock manure into the wastewater. If the amount of these organic substances eluted is large, the wastewater after the treatment in the adsorption tower 60 may not satisfy the water quality that can be discharged into the river.

In order to suppress the elution of such organic matter, it is desirable that the carbonized animal manure is produced by being carbonized at a high temperature as much as possible. By carbonizing at a high temperature (for example, 600 ° C to 900 ° C) during the production of charcoal of livestock manure, the amount of residual organic matter in the charcoal of livestock manure can be reduced, and the amount of organic matter eluted from the charcoal of livestock manure into wastewater can be suppressed. Is.

Further, in order to suppress the elution of organic matter, it is also effective to use the carbide of livestock manure that has been washed as an adsorbent. By washing the carbide of livestock manure, the organic matter remaining in the charcoal of livestock manure can be eluted in the washing water. Therefore, when the charcoal of livestock manure after washing is used as an adsorbent, the amount of organic matter eluted can be reduced as compared with the case of using the charcoal of livestock manure after washing.

When the carbonized animal manure is washed, the temperature of the carbonized animal manure does not necessarily have to be high. For example, a carbonized animal manure that has been carbonized at a temperature similar to or lower than that of the carbonized animal manure used as an organic fertilizer (for example, 450 ° C. or higher) may be washed and used as an adsorbent.

Further, it is desirable that the carbonized animal manure is activated by steam in at least a part of the carbonization treatment at the time of producing the carbonized animal manure. By performing the activation treatment with steam, gasification of carbon contained in the carbide of livestock manure occurs, and a fine structure is generated in the charcoal of livestock manure. Thereby, the specific surface area of the carbide of livestock manure can be increased. Therefore, it is possible to increase the amount of adsorbed antibiotics and decomposition products per unit amount of carbides of livestock manure. That is, the adsorption performance of carbides of livestock manure can be improved.

When activating with steam during the production of carbonized livestock manure, it is desirable that the temperature of the carbonization treatment of the carbonized livestock manure is higher. For example, in the case of chicken manure, it is desirable to carbonize at a temperature of 850 ° C. or higher and further activate with steam. As a result, the specific surface area of the carbide of livestock manure can be significantly increased.

According to the wastewater treatment system 200 described above, at least one of the antibiotic and the decomposition product of the antibiotic can be removed from the wastewater. The adsorption step is particularly effective in removing antibiotics that are difficult to decompose by heat. By combining this adsorption step and the heating step, antibiotics can be more reliably removed from the wastewater.

[Embodiment 3]
As described above, the type of antibiotic that thermally decomposes in the heating steps of the wastewater treatment systems 100 and 200 is not particularly limited. Further, in the adsorption step of the wastewater treatment system 200, the type of the antibiotic adsorbed by the adsorbent and the antibiotic before decomposition of the decomposed product to be adsorbed are not particularly limited.

For example, in at least one of the heating and adsorption steps of the wastewater treatment systems 100 and 200, aminoglycosides, tetracyclines, penicillins, peptides, macrolides, lincomycins, kilonones, polypeptides, polysaccharides, Antibiotics such as polyethers and cephem, as well as antifungal antibiotics can be degraded or adsorbed.

Examples of aminoglycoside antibiotics include apramycin sulfate, kanamycin sulfate, gentamicin sulfate, dihydrostreptomycin sulfate, streptomycin sulfate, fradiomycin sulfate and the like.

Examples of tetracycline antibiotics include alkyltrimethylammonium calcium oxytetracycline, oxytetracycline, oxytetracycline sulfate, chlortetracycline, chlortetracycline hydrochloride, doxycycline hydrochloride, and doxycycline hydrochloride hydrate.

Examples of penicillin-based antibiotics include amoxicillin, ampicillin, ampicillin sodium, cloxacillin sodium, dicloxacillin sodium, naphthylin sodium monohydrate, benzylpenicillin potassium, benzylpenicillin prokine, and mecillinum.

Examples of peptide-based antibiotics include thiostreptone and colistin sulfate.

Macrolide antibiotics include, for example, erythromycin, erythromycin thiosicate, spiramycin embonate, josamicin, tyrosin, tyrosin phosphate, tyrosin tartrate, tyrosin tartrate acetate, tilmicosin, tylmicosin phosphate, milosamycin, and vine. Examples include erythromycin.

Examples of the lincomycin-based antibiotic include clindamycin hydrochloride, lincomycin hydrochloride, lincomycin hydrochloride hydrate and the like.

Examples of the polypeptide antibiotic include zinc bacitracin, enramycin, nosiheptide, colistin sulfate and the like.

Examples of the polysaccharide-based antibiotic include flavophospolipol and the like.

Polyester antibiotics include sodium salinomycin, sodium senduramycin, narasin, monensin sodium, and sodium lasaroside.

Cefazolin antibiotics include cephalexin, cefazolin sodium, cefazolin, cefthioflusodium, cefaronium, cefpodoxime proxetyl, cefloxim sodium, cefobecin sodium, cefquinome sulfate, cefapilin sodium and cefapilin benza. Chin is mentioned.

In addition, for example, chloramphenicol, tiamulin, tiamulin fumarate, valnemulin hydrochloride, bicozamycin, bicozamycin benzoate, fosfomycin calcium, phosphomycin calcium hydrate, fosfomycin sodium, aviramycin, eftromycin, and virginiamycin, etc. The antibiotic can also be degraded or adsorbed in at least one of the heating and adsorption steps.

In addition, synthetic antibacterial agents, anthelmintic agents, and antiprotozoal agents can also be decomposed or adsorbed as antibiotics in a broad sense in at least one of the heating step and the adsorption step of the wastewater treatment systems 100 and 200. For example, synthetic antibacterial agents such as kilonone-based, thiamphenicol-based, furan-based, fluoroquinolone-based, and sulfa agents can be treated in at least one of a heating step and an adsorption step.

Examples of the quinolone-based synthetic antibacterial agent include oxolinic acid and the like.

Examples of the thianphenicol-based synthetic antibacterial agent include thianphenicol and florfenicol.

Examples of furan-based synthetic antibacterial agents include nitrofural and sodium niflustyrenate.

Examples of the fluoroquinolone-based synthetic antibacterial agent include norfloxacin, enrofloxacin, orbifloxacin, ofloxacin, marbofloxacin, danofloxacin mesylate, and lomefloxacin hydrochloride.

Synthetic antibacterial agents for sulfa drugs include sulfachlorpyridazine sodium, sulfadiazine, sulfadimidine (sulfamesazine), sulfadimethoxine, sulfadimethoxine sodium, sulfadoxine, sulfamethoxazole, sulfamelazine sodium, sulfamoyldapson, sulfamono. Examples thereof include methoxyne, sulfamonomethoxine hydrate, sulfamonomethoxine sodium, sulfisozole sodium, homosulfamine and the like.

In addition, synthetic antibacterial agents such as olmethoprim and trimethoprim can also be decomposed or adsorbed in at least one of the heating step and the adsorption step of the wastewater treatment systems 100 and 200.

Further, for example, anthelmintic agents such as avermectin-based, thiabendazole-based, and piperazine-based can be treated in at least one of the heating step and the adsorption step of the wastewater treatment system 100.

Examples of avermectin-based anthelmintics include ivermectin, eprinomectin, selamectin, drammectin, milbemycin oxime and moxidectin.

Examples of the thiabenzodal anthelmintic include triclabendazole, fenbendazole and flubendazole.

Examples of the piperazine-based anthelmintic agent include piperazine adipate, piperazine citrate and piperazine phosphate.

In addition, modepside, levamisole hydrochloride, oxyclozanide, digenea simplex, santonin, dichlorophen, disophenol, morantel tartrate, tribromsalan, pyrantel pamoate, phenothiazine, fevantel, praziquantel, bromphenofus, digenea simplex, metylidine, melansomine dihydrochloride, etc. Insecticide can also be treated.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

In the following examples, livestock wastewater, which is an example of wastewater, will be described as an example, but the present invention is widely applicable to wastewater, and the scope of application is not limited to livestock wastewater.

(Pyrolysis confirmation test of antibiotics)
(1: Purpose)
In this test, the possibility of thermal decomposition of antibiotics when the livestock wastewater was heated and the thermal decomposition rate were tested.

(2: Preparation of sample)
Pure water in which antibiotics were dissolved was diluted with a phosphate buffer solution to prepare a model solution for livestock wastewater. Oxytetracycline (OTC) and doxycycline (DOXY) were prepared as the antibiotics to be tested.

(3: Test conditions)
Two kinds of solutions, a model solution containing OTC and a model solution containing DOXY, were prepared. The initial concentration of OTC in the solution was adjusted to 5,100 ng / L. The initial concentration of DOXY in the solution was adjusted to 4,100 ng / L. The two solutions were heated for 120 hours. The heating temperature of the two types of solutions was 38 ° C, 60 ° C, and 80 ° C under three conditions.

(4: Test procedure)
A model solution (hereinafter referred to as an OTC solution) in which OTC was dissolved so as to have a concentration of 5,100 ng / L was prepared. A model solution (hereinafter referred to as DOXY solution) in which DOXY was dissolved so as to have a concentration of 4,100 ng / L was prepared.

500 mL polypropylene containers were prepared for the number of samples, and OTC solution or DOXY solution was poured into each container. The OTC and DOXY solutions were heated in a thermostat for 120 hours. When heating, the lid of the polypropylene container was closed to prevent the solution from evaporating.

Sampling was performed as shown in Table 1 below. That is, sampling is performed when 0 hours (0h), 1 hour (1h), 6 hours (6h), 24 hours (24h), 48 hours (48h), and 120 hours (120h) have elapsed after the start of heating. did. To prevent denaturation of antibiotics, 0.5 g of EDTA was added to the collected sample and stored in a refrigerator at 4 ° C. Then, the concentration of OTC or DOXY in each sample was measured.

(5: Test result)
FIG. 3 is a diagram showing changes over time in the concentration of antibiotics in a solution due to thermal decomposition. FIG. 3 (a) shows the OTC concentration, and FIG. 3 (b) shows the time course of the DOXY concentration. The initial concentration of OTC in the OTC solution was 5,100 ng / L, and the initial concentration of DOXY in the DOXY solution was 4,100 ng / L. As shown in the figure, the antibiotic concentration tended to decrease with the passage of time under all temperature conditions and in both the OTC solution and the DOXY solution.

The heating times of the OTC solution and the DOXY solution until the target water quality concentration (both 500 ng / L) was reached are as shown in Table 2 below.

The concentration of OTC in the OTC solution is within 6 hours when the heating temperature is 80 ° C, within 24 hours when the heating temperature is 60 ° C, and within 120 hours when the heating temperature is 38 ° C. It became less than the target water quality concentration (500 ng / L). The concentration of DOXY in the DOXY solution became less than the target water quality concentration (500 ng / L) within 48 hours when the heating temperature was 80 ° C.

In this test, it was confirmed that by heating the livestock wastewater, the antibiotic contained in the livestock wastewater can be thermally decomposed and the concentration of the antibiotic can be reduced. It was also confirmed that the rate of thermal decomposition differs depending on the type of antibiotic.

(6: Consideration)
When the conventional livestock wastewater treatment process is adopted, the residence time (total residence time) of the livestock wastewater in the entire wastewater treatment system may be, for example, about 7 to 14 days. In this case, the residence time in the aeration tank is about 4 to 8 days. The residence time in the aeration tank often accounts for more than half of the total residence time. Since the wastewater treatment systems 100 and 200 according to this embodiment include the first aeration tank 31 and the second aeration tank 32, the total residence time of the two tanks of the first aeration tank 31 and the second aeration tank 32 is It can be said that it is likely to occupy more than half of the total residence time. The residence time (total residence time) of livestock wastewater in the entire wastewater treatment system and the residence time in the aeration tank vary depending on the scale of the ranch that discharges livestock wastewater (in other words, the amount of livestock wastewater, etc.). To obtain, the above values are only an example.

Further, the wastewater treatment systems 100 and 200 according to the present embodiment include a heating tank 33 after the first aeration tank 31 and the second aeration tank 32. The residence time in the heating tank 33 can be arbitrarily changed by changing the size of the heating tank 33. In addition, livestock wastewater can be heated in the first aeration tank 31 and the second aeration tank 32.

Considering the results of the experiment using the OTC solution (particularly, Table 2), it can be predicted that the concentration of OTC will be less than the target water quality concentration within 24 hours when the livestock wastewater is heated at 60 ° C. Further, when the livestock wastewater is heated at 38 ° C., it can be predicted that the OTC concentration will be less than or equal to the target water quality concentration within 120 hours. On the other hand, in the experiment using the DOXY solution, as shown in Table 2, when the heating temperature was 80 ° C., the concentration of DOXY could be lowered to the target water quality concentration or less within 48 hours. Therefore, when trying to reduce the concentration of DOXY to the target water quality concentration or less within the residence time in the heating tank 33, it is desirable to heat the livestock wastewater at about 80 ° C.

In the wastewater treatment systems 100 and 200, as described above, by changing the size of the heating tank 33, it is possible to arbitrarily change the residence time of livestock wastewater in the heating tank 33, that is, the heating time. be. Therefore, when the wastewater treatment system 100 and the wastewater treatment system 200 are actually operated, it can be said that there is a sufficient possibility that the concentration of DOXY can be lowered to the target water quality concentration or less even at 80 ° C. or lower.

(Carbide adsorption test of livestock manure)
(1: Purpose)
In this test, in order to prove that the carbide of livestock manure can be used as an adsorbent for antibiotics and organic substances in the wastewater treatment system 200, a method for producing the charcoal of livestock manure having high adsorption performance was examined.

(2: Preparation of sample)
Carbide of chicken manure and charcoal of pig manure were prepared as samples. The number of samples and the number of each sample (sample number) are as shown in Table 3 below. Carbide from chicken manure was used in the specific surface area measurement test and the methylene blue (MB) adsorption test, which will be described later. Carbide pig feces was used in the MB adsorption test.

The production conditions for carbide chicken manure and carbide pig manure are as shown in Table 3 below. The column of "Sample No." indicates the sample number assigned to each sample. The "Ingredients" column shows the raw materials for carbides. The "Conditions" column shows the carbonization method. "Carbonization 1" indicates that a sample was prepared by a carbonization method in an actual carbonization facility (that is, a carbonization method in the production of ordinary livestock manure carbonization, which is a carbonization method of heating under oxygen-free conditions). On the other hand, "Carbide 2" indicates that a sample was prepared by a method of activating carbonization by carrying out a normal carbonization method and reacting carbonization with steam from 10 minutes before the end of carbonization to the end.

The column "Carbonization temperature (° C.)" shows the carbonization temperature when carbonizing livestock manure in degrees Celsius. The column of "Carbonization time (minutes)" shows the carbonization time (that is, the heating time of livestock manure). In this example, a sample having a particle size of 100 μm or less in a mortar or pestle was used in the experiment.

(3: Test method)
(3-1: Measurement of specific surface area)
The specific surface area of the carbide samples 2 to 7 of chicken manure was measured using an automatic gas adsorption measuring device (BELLSORP-mini, manufactured by Microtrac Bell). The test was carried out in the following order (1) and (2).

(1) Each sample of charcoal chicken manure was crushed in a mortar and pretreated.

(2) A sample was set in an automatic gas adsorption measuring device, and the specific surface area was measured using nitrogen gas as an adsorption medium.

(3-2: MB adsorption test)
According to the activated carbon test method (JIS K1474), the sample No. The adsorption performance of 2 to 7 was evaluated. In this test, first, for each sample prepared at various carbonization temperatures, the adsorption test was performed while changing the amount of the sample added, so that the MB residual concentration at each preparation temperature and the adsorbent unit mass were measured. The amount of MB adsorbed was calculated and plotted. Adsorption isotherms were created from this plot and the adsorption performance was calculated using the adsorption isotherms.

(4: Test result)
(4-1: Results of measurement of specific surface area)
FIG. 4 is a graph showing the measurement results of the specific surface area of carbides of chicken manure.

Sample No. 1 prepared by carbonization 1. In 2 to 4, the specific surface area decreased as the maximum temperature of carbonization increased. On the other hand, the sample No. prepared by carbonization 2 In 5 to 7, the specific surface area increased as the maximum temperature of carbonization increased. For example, sample No. 7 is sample No. The specific surface area was about 20 times that of 2.

(4-2: Results of MB adsorption test)
FIG. 5 is a graph showing the results of the MB adsorption performance test of carbides of chicken manure. For comparison, sample No. The MB adsorption performance of 1 (carbide of pig manure) and activated carbon is also shown in the graph.

Similar to the result of specific surface area, in the MB adsorption performance test, the sample No. 1 prepared by carbonization 1 was used. In 2 to 4, the adsorption performance decreased as the carbonization temperature increased. In addition, sample No. 3 and sample No. 5 is a sample having the same carbonization temperature but different only in the presence or absence of activation. Comparing these samples, no significant change in MB adsorption performance was observed with or without activation. On the other hand, sample No. For 6 to 7, sample No. Compared with 5, the MB adsorption performance increased up to about 10 times. The MB adsorption performance of activated carbon was 130 mL / g. From this, it was confirmed that when the carbonized chicken manure was produced at a high temperature (about 850 ° C. to 900 ° C.) and by the method of carbonization 2, the MB adsorption performance could be improved to about 1/5 of that of activated carbon. Assuming that the adsorption performance of antibiotics is also improved to the same level as the MB adsorption performance, when the carbonized chicken manure is produced at a high temperature (about 850 ° C to 900 ° C) and by the method of carbonization 2, the adsorption performance of antibiotics is also 1 / that of activated carbon. It is considered that it can be improved to about 5.

In addition, sample No. In No. 2, the MB adsorption performance could not be evaluated correctly because the MB adsorption amount did not change when the addition amount was increased.

(5: Conclusion)
The following conclusions were drawn from the results of the various tests shown in this example. That is, in the carbonized animal manure produced by carbonization 1, the MB adsorption performance was not improved even if the carbonization temperature was raised. On the other hand, in the carbonized animal manure produced by carbonization 2, the MB adsorption performance was increased to about 1/5 of that of activated carbon at the maximum by increasing the carbonization temperature.

From this, it was considered that the carbonization temperature was 850 ° C. and 900 ° C., and the adsorption performance of the antibiotic was improved to about 1/5 of that of the activated carbon for the carbonized animal manure produced by carbonization 2. Therefore, it can be said that the carbide of livestock manure can be a substitute for activated carbon as an adsorbent from the viewpoint of cost, depending on the production cost or the purchase price.

INDUSTRIAL APPLICABILITY The present invention can be suitably used as a wastewater treatment method in a facility for treating wastewater contained in livestock manure and livestock urine.

100, 200 Wastewater treatment system 10 Solid-liquid separation unit 1 Raw water tank 2 Solid-liquid separator 3 1st flow rate adjustment tank 4 2nd flow rate adjustment tank 5 Sludge storage tank 6 Sludge dehydrator 20 Solid matter treatment unit 30 Decomposition processing unit 31st 1 Aeration tank 32 2nd aeration tank 33 Heating tank 40 Membrane separation tank 50 Disinfection tank 60 Adsorption tower

Claims (7)

A heating process that decomposes antibiotics contained in the wastewater by heating the wastewater ,
A step of adsorbing the antibiotic and at least one of the decomposition products of the antibiotic to the adsorbent by bringing the wastewater into contact with the adsorbent.
The adsorption step is performed at least one before and after the heating step.
A wastewater treatment method, wherein the adsorbent is a carbide of livestock manure. The wastewater treatment method according to claim 1, wherein in the heating step, the wastewater is heated at a temperature of 38 ° C. or higher and 80 ° C. or lower. The wastewater treatment method according to claim 1 or 2 , wherein the wastewater is livestock wastewater. The method according to any one of claims 1 to 3 , wherein in the heating step, the waste heat generated when treating the livestock manure is used as at least a part of the heat source for heating the waste water. The described wastewater treatment method. A heating tank that accommodates wastewater and heats the wastewater to perform a heating step that decomposes the antibiotics contained in the wastewater.
Includes the antibiotic and an adsorption tower that performs an adsorption step of adsorbing at least one of the decomposition products of the antibiotic to the adsorbent by bringing the wastewater into contact with the adsorbent.
The adsorption step is performed at least one before and after the heating step.
A wastewater treatment system, wherein the adsorbent is a carbide of livestock manure. The wastewater treatment system according to claim 5 , wherein the heating tank utilizes waste heat generated when treating livestock manure as at least a part of a heat source for heating the wastewater. The wastewater treatment system according to claim 5 or 6 , wherein the wastewater is livestock wastewater.

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