JP2004188329A - Livestock waste water treatment system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an advanced livestock waste water treatment system capable of facilitating its maintenance and management and obtaining a stable final effluent. <P>SOLUTION: Livestock waste water D<SB>0</SB>is denitrified in a first denitrification tank 11, then biologically treated in a bioreactor 26 and nitrified in a nitrification tank 31. Activated sludge inside the nitrification tank 31 is returned to the first denitrification tank 11 by a first circulation pump 34. Nitrified waste water D<SB>4</SB>is denitrified in a second denitrification tank 37, then membrane-separated in an MF membrane tub 41 and turned to primary treated water W<SB>1</SB>. The activated sludge inside the MF membrane tub 41 is returned to the first denitrification tank 11 by a second circulation pump 51. Inorganics and high polymers in secondary treated water are agglutinated in a first agglutination tank and a second agglutination tank. The inorganics and the high polymers in the secondary treated water are coagulatively precipitated in a coagulative precipitation tank and the final effluent is attained. Even when the volumes of the respective tanks are reduced and loads are increased, the BOD, COD, SS, T-N and T-P of the final effluent are reduced. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a livestock wastewater treatment apparatus for treating livestock wastewater by nitrification and denitrification.
[0002]
[Prior art]
Conventionally, livestock manure is separated into solid and liquid in a livestock barn or discharged as wastewater in a state of mixing manure. Then, feces after solid-liquid separation can be composted by fermentation.For example, in the case of pig farming, urine equivalent to about twice the amount of feces produced in a day is generated. If you do not own the agricultural land to be returned to the land, or if the amount of liquid fertilizer to be returned is too large, it will cause soil contamination, which makes it difficult to treat.
[0003]
Here, taking concrete example of swine raising wastewater, the structure of the pig house and the concentration of the wastewater change by mixing sawdust, but generally, the biochemical oxygen demand (Biochemical Oxygen Demand: BOD) And the amount of suspended solids (Suspended Solids: SS) is more than 10000 mg / l. In particular, in BOD, the concentration becomes 50 times or more the concentration of domestic wastewater (BOD = about 200 mg / l), and the load related to biological treatment such as activated sludge is extremely large.
[0004]
For this reason, in the conventional livestock wastewater treatment equipment, the BOD load is reduced to cope with a large-scale wastewater treatment facility, and when there is no facility space, the BOD load is increased to reduce the size of the facility. For the purpose, it is necessary to use a biological treatment method such as a carrier flow method or a membrane separation activated sludge. At this time, even if each of BOD and SS is efficiently purified, a high concentration of Chemical Oxygen Demand (COD), nitrogen, and phosphorus remain in the treated water, and these are regulated values. In some areas, it is also required to remove these COD, nitrogen and phosphorus.
[0005]
Further, as a livestock wastewater treatment technology used in this kind of livestock wastewater treatment apparatus, an activated sludge method, a lagoon method, an oxidation ditch method (OD method) and the like are generally used.
[0006]
However, in such a method, the quality of the treated water is difficult to stabilize due to deterioration of the sedimentation of the sludge due to bulking and floating of the sludge due to seasonal variation, difference in the amount of water used, and variation in the concentration of the raw water.
[0007]
In addition, livestock wastewater has a higher concentration of pollutants than other business wastewater, and it is not easy to maintain and manage the wastewater treatment facilities. Therefore, livestock wastewater treatment equipment that can obtain stable treated water without sludge runoff Is eagerly awaited.
[0008]
On the other hand, in areas where there is no regulation on nitrogen (N) and phosphorus (P), and the discharge regulation value is moderate, even if only BOD treatment is performed, high concentrations of total nitrogen (T-N = 2000) ５5000 mg / l), and the nutritional balance in the livestock wastewater, such as BOD and TN, is extremely biased, and it is highly possible that the microbial activity is adversely affected. Therefore, it is essential to remove nitrogen when treating such livestock wastewater.
[0009]
In addition, the additional regulations of each prefecture based on the Water Pollution Control Law of the environment-related laws and regulations add COD, which is a total amount regulation, and nitrogen and phosphorus regulations, and consider not only nitrogen removal but also COD and phosphorus removal. The installation of wastewater treatment equipment has become mandatory, but the cost of wastewater treatment equipment borne by livestock farmers who raise livestock is enormous, and it is not easy to comply with laws and regulations.
[0010]
[Problems to be solved by the invention]
As described above, in the conventional activated sludge method, the lagoon method and the oxidation ditch method, the quality of the treated water is difficult to stabilize due to seasonal fluctuations, differences in the amount of water used, and fluctuations in the raw water concentration. Since the pollutant concentration is high, there is a problem that maintenance and management are not easy and it is not easy to obtain stable treated water.
[0011]
The present invention has been made in view of such a point, and an object of the present invention is to provide a livestock wastewater treatment apparatus which can easily maintain and manage and obtain stable treated water.
[0012]
[Means for Solving the Problems]
The livestock wastewater treatment apparatus according to claim 1, wherein a first denitrification tank for denitrifying livestock wastewater, a treatment tank for biologically treating the wastewater denitrified in the first denitrification tank, and this treatment tank A nitrification tank for nitrifying wastewater that has been biologically treated in step 1, first sludge return means for returning sludge in the nitrification tank to the first denitrification tank, and wastewater nitrified in the nitrification tank. A second denitrification tank for denitrifying the wastewater, a membrane separation tank for subjecting the wastewater denitrified in the second denitrification tank to membrane separation, and the sludge in the membrane separation tank to the first denitrification tank. And a coagulating sedimentation tank for coagulating and sedimenting the wastewater subjected to membrane separation in the membrane separation tank and removing inorganic substances and polymer substances from the wastewater. is there.
[0013]
Then, after the livestock wastewater is denitrified in the first denitrification tank, the sludge in the nitrification tank for nitrifying the wastewater biologically treated in the treatment tank is returned to the first denitrification tank by the first sludge return means. Let it. After the nitrification treatment in the nitrification tank, the wastewater subjected to the denitrification treatment in the second denitrification tank is subjected to the membrane separation treatment in the membrane separation tank. At this time, the sludge in the membrane separation tank is returned to the first denitrification tank by the second sludge return means. Further, the wastewater subjected to the membrane separation treatment in the membrane separation tank is coagulated and settled in the coagulation sedimentation tank, and inorganic substances and polymer substances are removed from the wastewater to obtain treated water. As a result, even if the first denitrification tank, the treatment tank, the nitrification tank, the second denitrification tank, the membrane separation tank, and the coagulation sedimentation tank were made relatively small and the load was high, even if the load was high, the treatment was carried out experimentally. Water biochemical oxygen demand, chemical oxygen demand, buoyant substances, nitrogen, phosphorus, etc. are each efficiently reduced, so maintenance is easy and stable treated water is easily obtained. .
[0014]
The livestock wastewater treatment device according to claim 2 is the livestock wastewater treatment device according to claim 1, further comprising a third denitrification tank that performs a denitrification treatment on the wastewater subjected to the membrane separation treatment in the membrane separation tank, and a coagulation sedimentation tank. The wastewater that has been denitrified in the third denitrification tank flows into the tank.
[0015]
Then, the wastewater subjected to the membrane separation treatment in the membrane separation tank is subjected to a denitrification treatment in a third denitrification tank, and the wastewater subjected to the denitrification treatment in the third denitrification tank flows into the coagulation sedimentation tank. Even if the organic nitrogen in the wastewater becomes nitrite nitrogen and nitrate nitrogen in the separation tank, the nitrite nitrogen and nitrate nitrogen are removed as nitrogen gas by denitrification of the wastewater in a third denitrification tank. As a result, the denitrification treatment of the wastewater becomes more reliable.
[0016]
According to a third aspect of the present invention, in the livestock wastewater treatment apparatus according to the first or second aspect, the first denitrification tank, the treatment tank, and the nitrification tank are filled with different carriers.
[0017]
The first denitrification tank, the treatment tank and the nitrification tank are filled with different carriers, whereby the first denitrification tank is used for denitrification of wastewater, the treatment tank is subjected to biological treatment, and the nitrification tank is used for treatment. As each of the nitrification treatments of the wastewater becomes more efficient, appropriate treatment of the livestock wastewater becomes more efficient.
[0018]
The livestock wastewater treatment apparatus according to claim 4 is the livestock wastewater treatment apparatus according to any one of claims 1 to 3, wherein the membrane separation tank uses a membrane to remove organic nitrogen derived from particulate matter exceeding 0.45 μm in the wastewater. What separates.
[0019]
The organic nitrogen derived from the particulate matter exceeding 0.45 μm in the wastewater is separated by membrane in the membrane separation tank, so that the organic nitrogen can be efficiently separated from the wastewater. The outflow of nitrogen can be prevented, and the amount of nitrogen in the treated water can be efficiently reduced.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a configuration of an embodiment of a livestock wastewater treatment apparatus of the present invention will be described with reference to FIGS. 1 and 2.
[0021]
1 and 2, reference numeral 1 denotes a livestock wastewater advanced treatment system as a livestock wastewater treatment device. This livestock wastewater advanced treatment system 1 includes a biochemical oxygen demand (BOD) treatment process and a denitrification process. This is a system that combines processing steps.
[0022]
The advanced livestock sewage treatment system 1 includes an adjusting tank 2 as a pretreatment tank. The adjusting tank 2 has a livestock effluent D before treatment that has passed through a 0.5 mm fine mesh screen. ₀ Are stored undiluted. This regulating tank 2 contains livestock wastewater D before treatment. ₀ And adjust the concentration and inflow of water.
[0023]
Here, livestock wastewater D as undiluted raw water before this treatment is used. ₀ On average, the BOD is about 8500 to 19000 mg / l, the chemical oxygen demand (Chemical Oxygen Demand: COD) is about 4200 to 12500 mg / l, and the amount of suspended solids (Suspended Solids: SS) is 9100 to It is about 15000 mg / l, total nitrogen (TN) is about 2500-6600 mg / l, and total phosphorus (TP) is about 250-1000 mg / l.
[0024]
Further, the adjusting tank 2 has a livestock wastewater D therein. ₀ Is provided with a bottomed tank body 3, and a diffuser as a diffuser is attached inside the tank body 3. This diffuser is provided with livestock wastewater D stored in the tank body 3. ₀ And the livestock wastewater D ₀ Supply and circulation of air, particularly oxygen, to make the concentration uniform, etc. ₀ Prevent corruption.
[0025]
Further, on the downstream side of the adjusting tank 2, the livestock wastewater D pretreated in the adjusting tank 2 is disposed. ₁ There is provided a first denitrification tank 11 into which a predetermined amount of water flows in at an overflow. The first denitrification tank 11 is provided with livestock wastewater D in the first denitrification tank 11. ₁ Nitrite nitrogen and nitrate nitrogen therein are removed as nitrogen gas by the action of anaerobic bacteria, that is, denitrification treatment is performed. Further, the first denitrification tank 11 is provided with livestock wastewater D that has been pretreated in the adjustment tank 2. ₁ Is provided with a tank body 12 in which the livestock wastewater D in the tank body 12 is stored. ₁ A stirrer 13 is attached to stir and uniform the mixture.
[0026]
The stirrer 13 includes a motor 14 as a driving unit installed above the tank body 12, and a fan 16 is rotatably attached to the motor 14 via a shaft 15 as a shaft. ing. The fan 16 is provided at a lower central portion in the tank body 12. Further, the inside of the tank body 12 is filled with a plurality of first carriers 17 for denitrification, which are porous foams formed of hydrophilic polyethylene, so as to make up 30% of the volume of the tank body 12. The first carrier 17 contains livestock wastewater D ₁ The denitrifying bacteria which denitrify the nitrite nitrogen and nitrate nitrogen in it and turn them into nitrogen gas are fixed. This first carrier 17 is a livestock wastewater D ₁ Is a carrier for denitrification suitable for denitrification treatment of nitrocellulose, and is brought into fluid contact under anaerobic conditions in the tank body 12 to promote the denitrification reaction.
[0027]
Further, on the downstream side of the tank body 12, there is formed an overflow section 18 through which wastewater stored and denitrified in the tank body 12 overflows. The overflow portion 18 is provided with a first carrier 17 in the tank body 12 and a grid-like screen 19 for preventing overflow of a relatively large suspended substance or the like. Further, a washing device 20 as a diffuser for preventing adhesion of a floating substance to the screen 19 or the like by aeration is attached to the inside of the tank main body 12 below the screen 19. The cleaning device 20 is connected to a distal end of a second air pipe 22 connected to a discharge port of a second aeration blower 21 for discharging and supplying air. Further, the base end of the second air pipe 22 is connected to the discharge port of the first aeration blower 5.
[0028]
Next, on the downstream side of the first denitrification tank 11, the wastewater D denitrified in the first denitrification tank 11 is disposed. ₂ Biological treatment of organic nitrogen in the wastewater D ₂ In particular, a bioreactor 26 is installed as a treatment tank for lowering the BOD. Further, the bioreactor 26 is provided with a drainage D that overflows from the overflow section 18 of the first denitrification tank 11. ₂ Is provided with a bottomed tank main body 27 in which the gas is introduced and stored. The diffuser 4 is attached inside the tank main body 27. This diffuser 4 is provided with drainage D in the tank body 27. ₂ And drain this D ₂ Air, especially oxygen, is supplied into the wastewater to activate the biodegradation of the wastewater by aerobic bacteria. ₂ BOD is reduced and the wastewater D ₂ Is circulated in the tank body 27.
[0029]
Further, inside the tank main body 27, a plurality of second carriers 28, which are porous foams formed of biocarrier plastic, for example, polypropylene and activated carbon, make up 20% of the volume of the tank main body 27. The second carrier 28 is filled with drainage D ₂ BOD oxidizing bacteria, etc., which are subjected to biological treatment for lowering the BOD of bacteria, are fixed. The second carrier 28 is a carrier for BOD treatment suitable for biological treatment different from the first carrier 17, and is brought into fluid contact under aerobic conditions in the tank body 27 to promote the BOD oxidation reaction. . Further, on the downstream side of the tank body 27, an overflow section 18 to which a screen 19 and a washing device 20 are attached is provided.
[0030]
Further, on the downstream side of the bioreactor 26, wastewater D biologically treated by the bioreactor 26 is disposed. ₃ A nitrification tank 31 for nitrifying nitrogen, particularly ammoniacal nitrogen, into nitrite nitrogen and nitrate nitrogen is provided. In addition, the nitrification tank 31 is provided with wastewater D overflowing from the overflow section 18 of the bioreactor 26. ₃ Is provided with a bottomed tank main body 32 in which the wastewater D is stored in the tank main body 32. ₃ And drain this D ₃ Air, especially oxygen, is supplied to the inside to activate nitrification of the wastewater by aerobic bacteria, ₃ Is diffused in the tank body 32.
[0031]
The inside of the tank main body 32 is filled with a plurality of third carriers 33 as a porous foam formed of hydrophilic polyurethane so as to make up 20% of the volume of the tank main body 32. The third carrier 33 has drainage D ₃ Nitrifying bacteria that nitrify the ammoniacal nitrogen therein into nitrite nitrogen and nitrate nitrogen are fixed. The third carrier 33 is a nitrification carrier which is different from the first carrier 17 and the second carrier 28 and is suitable for nitrification treatment. Nitrogen is converted into nitrite nitrogen and nitrate nitrogen. Further, on the downstream side of the tank main body 32, an overflow section 18 to which a screen 19 and a washing device 20 are attached is provided.
[0032]
Further, inside the tank body 32 of the nitrification tank 31, there is provided a second sludge returning means as first sludge returning means for returning the activated sludge (not shown) in the tank body 32 into the tank body 12 of the first denitrification tank 11. One circulation pump 34 is provided. The first circulation pump 34 is installed below the screen 19 in the tank main body 32. Further, a base end of a sludge return pipe 35 as a sludge return line is connected to a discharge port of the first circulation pump 34, and a distal end of the sludge return pipe 35 is connected to the first denitrification tank 11. It is located above the tank body 12.
[0033]
Next, on the downstream side of the nitrification tank 31, the wastewater D that has been nitrified in the nitrification tank 31 is disposed. ₄ A second denitrification tank 37 for denitrifying the wastewater is provided. The second denitrification tank 37 is configured similarly to the first denitrification tank 11.
[0034]
Further, on the downstream side of the second denitrification tank 37, the wastewater D denitrified in the second denitrification tank 37 is disposed. ₅ Is provided with a microfilter (MF) membrane tank 41, which is a membrane separation tank for subjecting the water to a treatment water. This MF membrane tank 41 is provided with a drainage D overflowing from the overflow section 18 of the second denitrification tank 37. ₅ Is provided with a tank body 42 having a bottom, into which the wastewater D is stored in the tank body 42. ₅ A diffuser 43 for aerating the air is attached, and the diffuser 43 is connected to the second air pipe 22.
[0035]
Further, the drainage D in the tank body 42 is provided inside the tank body 42. ₅ Treated water W as membrane separation water that is wastewater from wastewater ₁ Is provided with a submerged membrane unit 44 as a membrane separation means for separating the membrane with a microfilter membrane (not shown) as a microfiltration membrane. The submerged membrane unit 44 is installed on the downstream side in the tank main body 42. Here, the microfilter membrane of this submerged membrane unit 44 is made of chlorinated polyethylene, and is set so as to separate solid particles from particles having a size of 0.45 μm or more, particularly organic nitrogen component particles. Primary treatment water W for reactive nitrogen ₁ Outflow to the primary treated water W ₁ Water W generated from ₃ Is efficiently reduced.
[0036]
Further, in the inside of the submerged membrane unit 44, drainage D which is subjected to membrane separation by the submerged membrane unit 44 is provided. ₅ A diffuser 45 for aerating the air is attached. The air diffuser 45 is connected to a third air pipe 47 connected to the discharge port of the film blower 46. Here, the discharge ports of the film blower 46 are connected to the discharge ports of the first aeration blower 5 and the second aeration blower 21, respectively.
[0037]
A baffle 48 is attached inside the tank main body 42 of the MF membrane tank 41 as a partition that partitions the inside of the tank main body 42 into an upstream side and a downstream side. The baffle 48 is used for drainage D stored in the tank body 42. ₅ Of the tank body 42, ₅ Regulates the flow above. The activated sludge (not shown) separated by the membrane separation by the submerged membrane unit 44 in the tank body 42 is provided upstream of the baffle 48 in the tank body 42 with the tank body of the first denitrification tank 11. A second circulation pump 51 is provided as a second sludge return means for returning the sludge to the inside. The second circulation pump 51 is connected to a base end of the sludge return pipe 35. Further, a drawing pump 52 is provided upstream of the baffle 48 in the tank main body 42 to draw out the activated sludge in the tank main body 42 and transfer it to a sludge storage tank (not shown).
[0038]
Here, on the upper part of the submerged membrane unit 44, the primary treated water W after the membrane separation in the submerged membrane unit 44 is performed. ₁ Is connected to a drain pipe 53 for discharging water to the outside. Here, the primary treated water W ₁ On average, BOD is about 2 to 12 mg / l, COD is about 98 to 400 mg / l, SS is about 5 to 10 mg / l, and T-N is about 27 to 45 mg / l. , T-P is about 6 to 10 mg / l.
[0039]
Further, the primary treated water W in the drain pipe 53 is provided in the drain pipe 53. ₁ A negative pressure gauge 54 for measuring the pressure of the gas is attached. Further, on the downstream side of the drainage pipe 53 from the negative pressure gauge 54, the primary treated water W separated by membrane in the submerged membrane unit 44 is provided. ₁ A primary treated water discharge pump 55 for extracting the water is attached. Further, a constant flow valve 56 and a flow meter 57 are attached to a drain pipe 53 downstream of the primary treated water discharge pump 55.
[0040]
Downstream of the drain pipe 53 to which the constant flow valve 56 and the flow meter 57 are attached, the primary treated water W separated by the membrane in the MF membrane tank 41 is disposed. ₁ Denitrification treatment and secondary treatment water W ₂ A third denitrification tank 61 is provided. The third denitrification tank 61 is configured in the same manner as the first denitrification tank 11, and the drainage D stored in the MF membrane tank 41 ₅ When the organic nitrogen contained therein becomes nitrite nitrogen and nitrate nitrogen, the nitrite nitrogen and nitrate nitrogen are denitrified and removed as nitrogen gas.
[0041]
Further, the tank body 12 of the third denitrification tank 61 is provided with the primary treated water W in the tank body 12. ₁ A chemical solution injection means 62 for injecting a chemical solution into the apparatus is attached. The chemical injection means 62 includes a chemical tank 63 in which a chemical such as methanol is stored. The chemical tank 63 is provided with the chemical in the chemical tank 63 in the tank body 12 of the third denitrification tank 61. A chemical liquid injection pump 64 for injecting about 2.5 times as much as nitrite nitrogen and nitrate nitrogen into the tank body 12 is attached.
[0042]
On the other hand, on the downstream side of the third denitrification tank 61, the secondary treated water W denitrified in the third denitrification tank 61 is provided. ₂ A first coagulation reaction tank 71 for coagulating an inorganic substance such as phosphorus (P) therein is provided. The first coagulation reaction tank 71 is provided with the secondary treated water W overflowing from the overflow section 18 of the third denitrification tank 61. ₂ The tank body 72 is provided with a stirrer 13 attached thereto.
[0043]
Further, the tank body 72 is provided with the secondary treated water W in the tank body 72. ₂ A first coagulant injecting unit 73 for injecting an inorganic coagulant such as iron salt is preferably attached to the first coagulant. The first flocculant injecting means 73 includes a flocculant tank 74 in which a flocculant is stored. The flocculant tank 74 is provided with the flocculant in the flocculant tank 74 in the tank main body 72. For example, a chemical liquid injection pump 64 for injecting at a flow rate of 400 mg / l is attached.
[0044]
Further, downstream of the first coagulation reaction tank 71, the secondary treated water W in which the inorganic substance has been coagulated in the first coagulation reaction tank 71. ₂ Aggregation reaction of high-molecular substances such as proteins in the second treatment water W ₂ A second agglutination reaction tank 76 for lowering the COD of the above is provided. The second coagulation reaction tank 76 is provided with the secondary treated water W overflowing from the first coagulation reaction tank 71. ₂ Is provided with a stirrer 13 attached thereto.
[0045]
The tank body 77 has a secondary treated water W inside the tank body 77. ₂ A second coagulant injecting means 78 for injecting a coagulant, preferably an amphoteric cationic polymer coagulant, more preferably a cationic coagulant such as T-766 (trade name), is provided. The second flocculant injecting means 78 includes a flocculant tank 74 in which a cationic flocculant is stored. The flocculant tank 74 has a cationic flocculant in the flocculant tank 74. A chemical injection pump 64 for injecting the agent into the tank body 77 is attached.
[0046]
Further, on the downstream side of the second agglutination reaction tank 76, the secondary treated water W decolorized by the agglutination reaction of the polymer substance in the second agglutination reaction tank 76 ₂ Flood water W by coagulating and sedimenting inorganic substances and polymer substances in the water ₃ A coagulation sedimentation tank 81 is provided. The coagulation sedimentation tank 81 is provided with the secondary treated water W overflowing from the second coagulation reaction tank 76. ₂ Is provided with a bottomed tank main body 82 into which is introduced and stored, and inside the tank main body 82, the secondary treated water W in the tank main body 82 is provided. ₂ An air lift pump 83 is provided for pumping water, such as inorganic substances and polymer substances, which have been subjected to a coagulation reaction and coagulated and precipitated. The air lift pump 83 is connected to the second air pipe 22.
[0047]
Further, a scum gap 84 for removing scum generated by agitation by aeration of the air lift pump 83 is attached inside the tank body 82. Here, the scum generated by the aeration by the air lift pump 83 is the second treated water W ₂ This is caused by coagulation and sedimentation of the inorganic substance or polymer substance which has undergone the coagulation reaction. Further, the scum gap 84 is also connected to the second air pipe 22. The scum removed by the scum gap 84 is transferred to a sludge storage tank (not shown).
[0048]
Further, on the downstream side of the coagulation and sedimentation tank 81 in the tank main body 82, the discharged water W after the inorganic substance and the polymer substance are coagulated and settled in the tank main body 82. ₃ An overflow weir 85 is provided to allow the water to overflow to the outside. Further, on the downstream side of the overflow weir 85, the discharged water W overflowing from the overflow weir 85 ₃ A disinfecting tank 91 for storing and disinfecting is stored. This disinfection tank 91 is provided with the discharge water W ₃ Is provided with a bottomed tank body 92 in which the discharged water W stored in the tank body 92 is provided. ₃ A disinfecting device 93 for disinfecting is provided.
[0049]
Further, on the downstream side of the disinfection tank 91, the discharged water W disinfected in the disinfection tank 91 is disposed. ₃ The discharge pump tank 94 in which the water is stored is provided adjacent to the discharge pump tank 94. The discharge pump tank 94 is provided with discharge water W disinfected in the disinfection tank 91. ₃ Is provided with a tank body 95 stored therein. The discharge water W stored in the tank body 95 is provided inside the tank body 95. ₃ A discharge pump 96 for discharging the water to a river or the like (not shown) is provided.
[0050]
Next, the livestock wastewater treatment method of the embodiment will be described.
[0051]
First, livestock wastewater D passed through a 0.5 mm fine mesh screen and stored undiluted in the tank body 3 of the adjustment tank 2. ₀ Is aerated while being agitated by the diffuser 4 in the tank body 3 and the livestock wastewater D in the tank body 3 is agitated. ₀ Livestock effluent D ₁ It is said.
[0052]
Next, this livestock wastewater D ₁ Is overflowed from the tank body 3 of the regulating tank 2 and stored in the tank body 12 of the first denitrification tank 11. At this time, this livestock wastewater D ₁ Is agitated by a stirrer 13 in the tank body 12 and is denitrified by the action of denitrifying bacteria fixed to the plurality of first carriers 17 in the tank body 12 to drain water D ₂ It becomes.
[0053]
And this drainage D ₂ After flowing through the screen 19 of the first denitrification tank 11, it overflows from the overflow section 18 and is stored in the tank body 27 of the bioreactor 26. At this time, this drainage D ₂ Is aerated by the diffuser 4 in the tank body 27, and is biologically treated by the action of the BOD oxidizing bacteria fixed to the second carrier 28 in the tank body 27 to lower the BOD and drain water D ₃ It becomes.
[0054]
Furthermore, this drainage D ₃ After flowing through the screen 19 of the bioreactor 26, it overflows from the overflow section 18 and is stored in the tank body 32 of the nitrification tank 31. At this time, this drainage D ₃ Is drained by the diffuser 4 in the tank main body 32 and the drainage D is caused by the action of nitrifying bacteria fixed to the third carrier 33 in the tank main body 32. ₃ Ammonia nitrogen in the water is nitrified into nitrite nitrogen and nitrate nitrogen, and wastewater D ₄ It becomes.
[0055]
The activated sludge in the nitrification tank 31 is returned to the first denitrification tank 11 by the first circulation pump 34 via the sludge return pipe 35.
[0056]
Furthermore, the wastewater D that has been nitrified in the nitrification tank 31 ₄ After flowing through the screen 19 of the nitrification tank 31, it overflows from the overflow section 18 and is stored in the tank body 12 of the second denitrification tank 37. At this time, this drainage D ₄ Is agitated by a stirrer 13 in the tank body 12, and is denitrified by the action of denitrifying bacteria fixed to the plurality of first carriers 17 in the tank body 12, and the wastewater D ₅ It becomes.
[0057]
In addition, this drainage D ₅ After passing through the screen 19 of the second denitrification tank 37, it overflows from the overflow section 18 and is stored in the tank body 42 of the MF membrane tank 41. And this drainage D ₅ Is aerated by an air diffuser 43 in the tank main body 42, and is subjected to primary separation water W by membrane separation by a submerged membrane unit 44 in the tank main body 42. ₁ And activated sludge are separated into solid and liquid.
[0058]
The activated sludge generated by the membrane separation by the submerged membrane unit 44 precipitates and accumulates in the tank body 42. Then, the activated sludge is returned to the first denitrification tank 11 via the sludge return pipe 35 by the second circulation pump 51, and is drawn out and stored in the sludge storage tank by the drawing pump 52. .
[0059]
Furthermore, the primary treated water W separated by membrane in the submerged membrane unit 44 ₁ Is discharged into the tank body 12 of the third denitrification tank 61 through the drain pipe 53 by the primary treatment water drain pump 55 and stored. At this time, the primary treated water W ₁ Is agitated by a stirrer 13 in the tank body 12, and the primary treated water W is agitated by the action of denitrifying bacteria fixed to the plurality of first carriers 17 in the tank body 12. ₁ Nitrite nitrogen and nitrate nitrogen in the water are denitrified and secondary treated water W ₂ It becomes.
[0060]
And this secondary treatment water W ₂ Flows over the overflow section 18 while passing through the screen 19 of the third denitrification tank 61, and is stored in the tank body 72 of the first coagulation reaction tank 71. ₂ After an inorganic substance such as phosphorus in the second coagulation reaction tank 76 undergoes an agglutination reaction, the second treatment water W is stored in a tank body 77 of the second agglutination reaction tank 76. ₂ Aggregation reaction of high molecular substances such as proteins inside.
[0061]
Thereafter, the secondary treated water W in which the polymer substance has undergone an agglutination reaction in the second agglutination reaction tank 76 ₂ Is stored in the tank body 82 of the coagulation sedimentation tank 81, and is stirred by aeration by the air lift pump 83. ₂ The coagulation-reacted inorganic substances and high-molecular substances in the coagulation settle to form scum, and this scum is removed by the scum skimmer 84 and the discharged water W ₃ It becomes.
[0062]
And this effluent W ₃ After overflowing from the overflow weir 85 of the coagulation sedimentation tank 81 and stored in the tank body 92 of the disinfection tank 91 and disinfected by the disinfecting device 93, it is stored and discharged in the tank body 95 of the discharge pump tank 94. The water is discharged to a river by a pump 96.
[0063]
As described above, according to the embodiment, the pretreated livestock wastewater D ₁ Is subjected to denitrification treatment in the first denitrification tank 11 in an undiluted state, and then subjected to biological treatment in the bioreactor 26 and nitrification treatment in the nitrification tank 31. At this time, the activated sludge in the nitrification tank 31 is returned to the first denitrification tank 11 via the sludge return pipe 35 by the first circulation pump 34, and the wastewater treated by the nitrification in the nitrification tank 31 is discharged. D ₄ Is subjected to a denitrification treatment in a second denitrification tank 37, and then is subjected to primary treatment water W in a submerged membrane unit 44 of an MF membrane tank 41. ₁ And activated sludge.
[0064]
Further, the activated sludge generated by the membrane separation in the MF membrane tank 41 is returned by the second circulation pump 51 to the first denitrification tank 11 via the sludge return pipe 35, and the MF membrane tank is also returned. Primary treatment water W by membrane separation in 41 ₁ Is subjected to a denitrification treatment in a third denitrification tank 61 to form a second treated water W ₂ After that, an inorganic substance such as phosphorus is caused to undergo an agglutination reaction in the first agglutination reaction tank 71, and a polymer substance such as a protein is caused to undergo an agglutination reaction in the second agglutination reaction tank.
[0065]
Thereafter, the secondary treatment water W in which the inorganic substance and the polymer substance have undergone an agglutination reaction ₂ Is coagulated and settled in the coagulation sedimentation tank 81, and the secondary treatment water W ₂ To reduce COD and release phosphorus to discharge water W ₃ And
[0066]
As a result, conventionally, the BOD volume load in the bioreactor of the livestock wastewater treatment device including the bioreactor, the denitrification tank and the nitrification tank is 0.3 to 0.5 kg / m. ^Three ・ Set to about day, load in denitrification tank is 0.12-0.3kg / m ^Three ・ It is set to about day, and the load in the nitrification tank is 0.06-0.25kg / m ^Three ・ It was set to about day.
[0067]
On the other hand, in the above embodiment, the NO in the first denitrification tank 11 of the advanced livestock wastewater treatment system 1 with a wastewater flow rate of 33 l / day is described. _X -N load 0.5 ~ 1.5kg / m ^Three ・ Set to about day, and set the BOD volume load in the bioreactor 26 and the nitrification tank 31 to 1.5 to 2.3 kg / m. ^Three ・ Set to about day, NH of this nitrification tank 31 ₄ -N load 0.3 ~ 0.7kg / m ^Three Day, the nitrification liquid circulation ratio as the sludge return ratio from the nitrification tank 31 to the first denitrification tank 11 is set to about 3 to 7, and the NO of the second denitrification tank 37 is set. _X -N load 0.3 ~ 1.5kg / m ^Three ・ Set to about day, and set the BOD volume load in the MF membrane tank 41 to 1-2 kg / m. ^Three Day, the sludge return ratio from the MF membrane tank 41 to the first denitrification tank 11 is set to about 2 to 5, and the NO of the third denitrification tank 61 is set. _X -N load is 0.2 ~ 1.5kg / m ^Three ・ Set to about day.
[0068]
As a result, each of the first denitrification tank 11, the bioreactor 26, the nitrification tank 31, the second denitrification tank 37, the MF membrane tank 41, and the third denitrification tank 61 is set to a high load state. As a test result, the effluent W treated by the livestock wastewater advanced treatment system 1 at a temperature of about 17 to 20 ° C. ₃ , COD, SS, TN, and TP decrease efficiently.
[0069]
Where NO _X -N is nitrite nitrogen (NO ₂ -N) and nitrate nitrogen (NO ₃ -N). Further, NH ₄ -N is ammoniacal nitrogen. At this time, the drainage D in the nitrification tank 31 ₃ Has a pH of about 7.3 to 8.8, an amount of suspended solids in the mixture (Mixed Liquor Suspended Solids: MLSS) of about 7900 to 28000 mg / l, and an amount of dissolved oxygen (Dissolved Oxygen: DO) of 2 to 3 mg / l. Furthermore, the livestock wastewater D in the first denitrification tank 11 at this time is ₁ And drainage D in the second denitrification tank 37 ₄ Have a pH of about 7 to 9 and a DO of about 0 to 0.3 mg / l.
[0070]
Therefore, these first denitrification tank 11, bioreactor 26, nitrification tank 31, second denitrification tank 37, MF membrane tank 41, third denitrification tank 61, first agglutination reaction tank 71, and second agglutination reaction Even if the respective volumes of the tank 76 and the coagulation sedimentation tank 81 are made relatively small and the load is high, the livestock wastewater D ₀ Effluent W after treating ₃ , COD, SS, TN and TP can be efficiently reduced. Therefore, the maintenance and management of the advanced livestock wastewater treatment system 1 can be facilitated, and the stable discharge water W ₃ Can be easily obtained.
[0071]
Further, the first denitrification tank 11, the bioreactor 26, the nitrification tank 31, the second denitrification tank 37, the MF membrane tank 41, the third denitrification tank 61, the first agglutination reaction tank 71, the second agglutination reaction By making the respective volumes of the tank 76 and the coagulation sedimentation tank 81 relatively small and compact, the first aeration blower 5 and the second aeration blower 21 for sending air to each diffuser 4 and each washing device 20, In addition, the size of each of the motor 14 for driving each agitator 13 and the membrane blower 46 for sending air to the submerged membrane unit 44 can be reduced. Therefore, the running costs of the equipment facilities such as the first aeration blower 5, the motor 14, the second aeration blower 21, and the membrane blower 46 can be reduced, and the maintenance and management of the advanced livestock wastewater treatment system 1 can be more easily performed. it can.
[0072]
Furthermore, the primary treated water W separated by membrane in the MF membrane tank 41 ₁ Is subjected to a denitrification treatment in a third denitrification tank 61 to produce a second treated water W ₂ After that, this secondary treated water W ₂ Is subjected to an agglutination reaction between the inorganic substance and the polymer substance in the first and second coagulation reaction tanks 71 and 76, and the inorganic substance and the polymer substance are coagulated and precipitated in the coagulation / sedimentation tank 81. ₃ Effluent D in the MF membrane tank 41 ₅ Even if the organic nitrogen in the wastewater becomes nitrite nitrogen and nitrate nitrogen, this wastewater D ₅ Since the nitrite nitrogen and nitrate nitrogen in the wastewater can be removed as nitrogen gas by the denitrification treatment in the third denitrification tank 61, the livestock wastewater D ₀ Denitrification can be more reliably performed.
[0073]
Further, the first carrier 17 suitable for the denitrification treatment is filled in each of the first denitrification tank 11, the second denitrification tank 37, and the third denitrification tank 61, and the organism different from the first carrier 17 The bioreactor 26 is filled with a second carrier 28 suitable for the treatment, and a third carrier 33 suitable for the nitrification treatment different from each of the first carrier 17 and the second carrier 28 is supplied to the nitrification tank 31. The first denitrification tank 11, the second denitrification tank 37, the third denitrification tank 61, the denitrification treatment in the bioreactor 26, and the nitrification treatment in the nitrification tank 31 Effluent D ₀ The appropriate processing can be surely and more efficiently performed.
[0074]
Furthermore, in general, livestock wastewater D ₀ Since most of the organic nitrogen component particles contained in the MF membrane tank 41 exceed 0.45 μm, by setting the micro filter membrane of the submerged membrane unit 44 of the MF membrane tank 41 to 0.45 μm, Drainage D ₅ Membrane from organic nitrogen accurately and efficiently from primary water W ₁ Can be. Therefore, the primary treated water W ₁ Outflow of organic nitrogen to the primary treated water W ₁ Discharge water W from ₃ TN can be suppressed by efficiently reducing the amount of nitrogen in the steel.
[0075]
In the above-described embodiment, a third denitrification tank 61 is provided between the MF membrane tank 41 and the first coagulation reaction tank 71, and the wastewater D is discharged in the MF membrane tank 41. ₅ When the organic nitrogen in the waste water becomes nitrite nitrogen and nitrate nitrogen, the wastewater D ₅ The nitrite nitrogen and nitrate nitrogen contained therein were removed as nitrogen gas by the denitrification treatment in the third denitrification tank 61. ₅ The third denitrification tank 61 may not be provided if there is no possibility that the organic nitrogen contained therein will become nitrite nitrogen and nitrate nitrogen.
[0076]
【Example】
Hereinafter, an example of the livestock wastewater advanced treatment system 1 according to the embodiment will be described.
[0077]
First, undiluted livestock wastewater D before treatment stored in the tank body 3 of the adjustment tank 2 ₀ Was measured, the BOD was 8567 mg / l, the COD was 4200 mg / l, the SS was 9100 mg / l, the TN was 2533 mg / l, and the TP was 257 mg / l.
[0078]
Then, the NO of the first denitrification tank 11 of the livestock wastewater advanced treatment system 1 in which the amount of wastewater is 33 l / day. _X -N load is 1.48kg / m ^Three ・ Set to day and set the BOD volume load in the bioreactor 26 and the nitrification tank 31 to 1.69 kg / m. ^Three ・ Set to day, NH of this nitrification tank 31 ₄ -N load 0.58kg / m ^Three Day and the nitrification liquor circulation ratio from the nitrification tank 31 to the first denitrification tank 11 is set to 3.22.
[0079]
Also, the NO of the second denitrification tank 37 _X -N load is 1.25kg / m ^Three ・ Set to about day, and set the BOD volume load in the MF membrane tank 41 to 2.00 kg / m ^Three Day, the sludge return ratio from the MF membrane tank 41 to the first denitrification tank 11 is set to 4.36, and the NO of the third denitrification tank 61 _X -N load is 1.00kg / m ^Three ・ Set to day.
[0080]
In this state, as a result of operating this livestock wastewater advanced treatment system 1, livestock wastewater D at the entrance of the first denitrification tank 11 was obtained. ₁ Had a calculated BOD of 1400 mg / l.
[0081]
At this time, drainage D at the entrance of the second denitrification tank 37 ₄ As a result of analysis, BOD was 453 mg / l, COD was 2200 mg / l, SS was 4687 mg / l, TN was 643 mg / l, and TP was 240 mg / l.
[0082]
Further, the primary treated water W after the membrane separation treatment in the MF membrane tank 41 is performed. ₁ The analytical values were BOD of 2.3 mg / l, COD of 160 mg / l, SS of 5 mg / l, T-N of 268 mg / l and T-P of 128 mg / l. Was.
[0083]
Further, the effluent water W after the inorganic substance and the polymer substance are removed by the coagulation sedimentation in the coagulation sedimentation tank 81. ₃ Is the analytical value, BOD is 2.0 mg / l, COD is 98 mg / l, SS is 5 mg / l, TN is 27 mg / l, and TP is 6.4 mg / l. Met.
[0084]
Therefore, as described above, the respective volumes of the first denitrification tank 11, the bioreactor 26, the nitrification tank 31, the second denitrification tank 37, the MF membrane tank 41, and the third denitrification tank 61 are made relatively small. Even if the load is set to a high load state, as a test result, the discharged water W treated by the livestock wastewater advanced treatment system 1 ₃ , COD, SS, TN and TP can be effectively reduced.
[0085]
【The invention's effect】
According to the livestock wastewater treatment device of the first aspect, the first denitrification tank, the treatment tank, the nitrification tank, the second denitrification tank, the membrane separation tank, and the coagulation sedimentation tank are relatively small in volume, and high load is applied. Even so, on a trial basis, the biochemical oxygen demand of the treated water, the chemical oxygen demand, the buoyant substances, nitrogen and phosphorus, etc. can be effectively reduced, so that maintenance and management can be facilitated and stable Treated water can be easily obtained.
[0086]
According to the livestock wastewater treatment apparatus of the second aspect, in addition to the effect of the livestock wastewater treatment apparatus of the first aspect, the organic nitrogen in the wastewater in the membrane separation tank becomes nitrite nitrogen and nitrate nitrogen. Also, since nitrite nitrogen and nitrate nitrogen can be removed as nitrogen gas by denitrification of wastewater in the third denitrification tank, denitrification of wastewater can be performed more reliably.
[0087]
According to the livestock wastewater treatment device according to claim 3, in addition to the effects of the livestock wastewater treatment device according to claim 1 or 2, the first denitrification tank, the processing tank and the nitrification tank are filled with mutually different carriers, Since the denitrification treatment of wastewater by the first denitrification tank, the biological treatment of wastewater by the treatment tank, and the nitrification treatment of wastewater by the nitrification tank can be performed more efficiently, appropriate treatment of livestock wastewater can be performed more efficiently.
[0088]
According to the livestock wastewater treatment apparatus of the fourth aspect, in addition to the effect of the livestock wastewater treatment apparatus of any one of the first to third aspects, organic nitrogen derived from particulate matter exceeding 0.45 μm in the wastewater is treated by a membrane. Since organic nitrogen can be efficiently separated from the wastewater by membrane separation in the separation tank, the outflow of organic nitrogen into the treated water can be prevented, and the amount of nitrogen in the treated water can be efficiently reduced.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a part of an embodiment of a livestock wastewater treatment apparatus according to the present invention.
FIG. 2 is an explanatory view showing a part of the livestock wastewater treatment device.
[Explanation of symbols]
1. Livestock wastewater advanced treatment system as livestock wastewater treatment equipment
11 First denitrification tank
17 First carrier as carrier
26 Bioreactor as treatment tank
28 Second carrier as carrier
31 Nitrification tank
33 Third carrier as carrier
34 First circulation pump as first sludge return means
37 Second denitrification tank
41 MF membrane tank as membrane separation tank
51 Second circulation pump as second sludge return means
61 Third denitrification tank
81 Coagulation sedimentation tank

Claims (4)

A first denitrification tank for denitrifying livestock wastewater,
A treatment tank for biologically treating wastewater denitrified in the first denitrification tank;
A nitrification tank for nitrifying wastewater biologically treated in this treatment tank,
First sludge returning means for returning sludge in the nitrification tank to the first denitrification tank;
A second denitrification tank for denitrifying wastewater that has been nitrified in the nitrification tank;
A membrane separation tank for subjecting the wastewater denitrified in the second denitrification tank to a membrane separation treatment;
Second sludge return means for returning sludge in the membrane separation tank to the first denitrification tank;
A livestock wastewater treatment apparatus, comprising: a coagulation sedimentation tank for coagulating and sedimenting wastewater subjected to membrane separation treatment in the membrane separation tank, and removing inorganic substances and polymer substances from the wastewater. A third denitrification tank for denitrifying wastewater subjected to membrane separation in the membrane separation tank,
The livestock wastewater treatment apparatus according to claim 1, wherein the wastewater denitrified in the third denitrification tank flows into the coagulation sedimentation tank. The livestock wastewater treatment apparatus according to claim 1 or 2, wherein the first denitrification tank, the treatment tank, and the nitrification tank are filled with different carriers. The livestock wastewater treatment apparatus according to any one of claims 1 to 3, wherein the membrane separation tank performs membrane separation of organic nitrogen derived from particulate matter exceeding 0.45 µm in the wastewater.

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