JP4119998B2 - Anaerobic treatment tank equipped with nitrogen removal tank and sewage septic tank - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an anaerobic treatment tank for a sewage septic tank and a sewage septic tank for treating manure, other domestic wastewater, or combined sewage (hereinafter also referred to as sewage). More specifically, the present invention relates to an anaerobic treatment tank (for a sewage septic tank) that can effectively remove nitrogen, and a sewage septic tank incorporating the same.
[0002]
[Prior art]
As a conventional nitrogen removal method in a sewage septic tank, a biological nitrification / denitrification method using the action of microorganisms is mainly used. This method is a nitrification process in which ammonia nitrogen, which is the main component of nitrogen in influent wastewater, is oxidized to nitrite nitrogen by the action of nitrite bacteria and further to nitrate nitrogen by the action of nitrate bacteria under aerobic conditions. And a denitrification step of reducing nitrite nitrogen and / or nitrate nitrogen to nitrogen gas by the action of denitrifying bacteria under anoxic conditions.
FIG. 9 shows an example of a conventional sewage septic tank. An anaerobic filter bed first chamber 51, an anaerobic filter bed second chamber 52, a biological filtration tank 53, a treated water tank 54, and a disinfection tank 55 are arranged from the upstream side. (For example, refer to Patent Document 1). In this sewage septic tank, ammonia nitrogen in the influent sewage is oxidized (nitrified) into nitrate nitrogen in the biological filtration tank 53, and a part of this liquid is returned to the anaerobic filter bed tank first chamber 51 to be nitrated in the liquid. Nitrogen is removed by reducing (denitrifying) nitrogen to nitrogen gas.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-96285 [0004]
[Problems to be solved by the invention]
However, in such a method for removing nitrogen by biological treatment, ammonia nitrogen is not nitrified until nitrous acid bacteria and nitrate bacteria with a slow growth rate grow to a certain amount or more, particularly in the initial stage of operation. It cannot be removed. Moreover, since the activity of microorganisms decreases in winter and the processing ability decreases, the tank capacity must be increased to compensate for this.
The present invention is intended to solve these problems, and is suitable for a sewage septic tank and a sewage septic tank that can stably remove nitrogen even in the initial stage of operation and winter, and can make the entire capacity of the septic tank more compact than before. It is an object of the present invention to provide an anaerobic treatment tank that is incorporated into the slab.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has the following configuration. That is, the present invention
In the tank, a nitrogen removal tank 4 for removing nitrogen physically and chemically,
A pump 5 for pumping up the liquid in the tank from the liquid level of the lowest water level (LW L);
It is connected to this pump 5 and is provided with a flow rate adjusting device 6 for transferring a part of the pumped liquid to the outside of the tank and returning the excess liquid 8 to the nitrogen removing tank 4.
The liquid discharged from the nitrogen removal tank 4 is an anaerobic treatment tank 1 for a sewage purification tank (having a single tank structure) that circulates in the tank.
[0006]
Here, the anaerobic treatment tank is not a single tank, but can be an anaerobic treatment tank (having a two-chamber structure) divided into a first chamber 1a and a second chamber 1b from the upstream side. In this case, the nitrogen removal tank 4 is provided in a section of the first chamber 1a. In addition, a part of the second chamber 1b is composed of a pump 5 for pumping the liquid in the tank from the liquid level of LW L, and a pump connected to the pump 5. A flow rate adjusting device 6 for returning the excess liquid to the nitrogen removal tank 4 is provided while being transferred to the outside of the tank. Further, the partition 22 between the first chamber 1a and the second chamber 1b is provided with a communication port 23 at a liquid level of L.W.L.
[0007]
In addition, here, the tank body (outer wall portion) of the anaerobic treatment tank 1 or the partition wall with the next tank is usually provided with an inlet 2 for receiving sewage and a discharge outlet 7 serving as an outlet. A part of the liquid pumped up by the pump 5 is sent from the outlet 7 to the next tank via the flow rate adjusting device 6.
[0008]
Moreover, what is preferable as the nitrogen removal tank 4 is a tank (electrolysis tank) that removes nitrogen by electrolysis. According to electrolysis, control and maintenance for nitrogen removal are easy, and nitrogen can be removed stably.
[0009]
Moreover, it is preferable to provide the filter bed 20 below the liquid level of the lowest water level in the tank of the anaerobic treatment tank 1. When the anaerobic treatment tank 1 is divided into the first chamber 1a and the second chamber 1b, a filter bed 20 may be provided in either the first chamber 1a or the second chamber 1b or in both chambers. preferable. When the filter bed 20 is provided, impurities contained in the inflowing sewage can be separated to prevent clogging of the pump 5 due to foreign matter, and anaerobic microorganisms are retained in the filter bed 20 and anaerobic of organic matter contained in the sewage. It is possible to effectively perform decomposition, denitrification of nitrate nitrogen, and reduction of sediment sludge.
[0010]
The present invention is also a sewage septic tank incorporating the anaerobic treatment tank. When the anaerobic treatment tank is a single tank anaerobic treatment tank 1, the sewage purification tank is typically anaerobic treatment tank second chamber 1 b arranged in order from the upstream, anaerobic treatment tank 1, and its downstream. This is a sewage purification tank including an aerobic treatment tank 30, a treated water tank 54 (precipitation tank) and a disinfection tank 33.
[0011]
In the case where the anaerobic treatment tank is an anaerobic treatment tank divided into a first chamber 1a and a second chamber 1b, the sewage purification tank typically has the anaerobic treatment tank 1 (first chamber 1a) from upstream. And a second chamber 1b), a sewage purification tank comprising an aerobic treatment tank 30, a treated water tank 54 (precipitation tank), and a disinfection tank 33, which are sequentially arranged in the downstream.
Various types of aerobic treatment tank 30, treated water tank 54 (sedimentation tank) or disinfection tank 33 can be used and are not particularly limited. Depending on the case, it is possible to omit one or both of the treated water tank 54 (precipitation tank) and the disinfection tank 33.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described more specifically with reference to the drawings.
FIG. 1 is an example (first embodiment) of an anaerobic treatment tank having a single tank structure according to the present invention. The tank body 24 of the anaerobic tank 1 is provided with the sewage inlet 2 at a height above the liquid level in the tank, the outlet 24 is provided in the tank body 24 on the opposite side, An electrolysis tank (nitrogen removal tank) 4 for removing nitrogen is provided. Also, on the wall side where the discharge port 7 is provided, a pump 5 for pumping the liquid in the tank from the liquid level of LW L and a part of the pumped liquid connected to the pump 5 are discharged. A flow rate adjusting device 6 is provided for transferring the excess liquid 8 into the electrolysis tank (nitrogen removal tank) 4 while transferring it to the port 7. Further, a baffle pipe 11 is provided around the pumping pump 5 in order to prevent inflow of foreign substances contained in the inflowing sewage and a short circuit of the sewage.
[0013]
The overall shape of the anaerobic treatment tank 1 is a substantially square shape (box shape) in plan view in FIG. This shape can be circular or elliptical in plan view, but is preferably a substantially square shape for simplicity.
[0014]
The excess liquid 8 in the flow rate adjusting device 6 is supplied to the electrolysis tank (nitrogen removal tank) 4 so that the liquid overflowing from the electrolysis tank (nitrogen removal tank) 4 returns to the anaerobic treatment tank 1. In FIG. 1, the electrolysis tank (nitrogen removal tank) 4 is provided in a part of the anaerobic treatment tank 1, but the surplus liquid 8 is supplied, and the liquid discharged from it returns to the anaerobic treatment tank 1. If present, it can be provided outside the tank. In order to increase the efficiency of the reaction, a stirring device may be provided in the electrolysis tank (nitrogen removal tank) 4. (Not shown)
[0015]
The suction port 10 of the pump 5 is provided at the LW L position. Then, the liquid level of the anaerobic treatment tank 1 depends on whether the influent amount of sewage is larger or smaller than the amount of liquid transferred from the flow control device 6 and the maximum water level (HWL). Fluctuate between. However, since H.W.L is set in advance for safety, the inflowing sewage does not overflow beyond the water level (H.W.L).
[0016]
In addition, although the pumping pump 5 has shown the air lift pump type in FIG. 1, it can replace with an air lift pump type and can also use the intermittent fixed_quantity | quantitative_assay pump, electric pump, etc. by pneumatic feeding of an airtight container.
[0017]
Any device can be used as long as it can adjust the flow rate adjusting device 6 so as to transfer a certain amount of liquid to the outlet 7 and return the excess liquid 8 to the nitrogen removing tank 4. Preferably, when the liquid level in the tank is LWL, an adjustable one such as a weir is used so that the entire amount of sewage pumped up by the pump 5 is transferred to the nitrogen removal tank 4 It is a flow control device. When such a flow control device 6 is used, the liquid in the tank of the anaerobic treatment tank 1 is repeatedly transferred to the electrolysis tank (nitrogen removal tank) 4 in a time zone in which sewage does not flow. Minutes are effectively removed.
[0018]
The flow rate ratio of the surplus liquid 8 to the liquid to be transferred to the discharge port 7 (hereinafter referred to as the circulation ratio) is usually 1 to 10, preferably 3 to 5. When the circulation ratio is less than 1, nitrogen in the inflowing sewage is not easily removed by the electrolysis tank (nitrogen removal tank) 4 and easily flows from the outlet 7 to the outside of the tank. Further, when the circulation ratio is larger than 10, it is necessary to increase the capacity of the flow rate adjusting unit 12 in order to prevent the inflowing sewage from overflowing.
[0019]
In the tank of the anaerobic treatment tank 1, a filter bed 20 is provided below the liquid level of L.W.L. When the upper end of the filter bed 20 is made higher than the liquid level of L.W.L, the upper part of the filter bed 20 becomes repeatedly below the surface of the water or exposed, so that the stability of sludge adhesion to the filter medium is improved. It has a bad effect.
[0020]
The shape of the filter bed 20 is not particularly limited, and plate-like members such as a loofah-like shape, a corrugated plate shape, and a porous shape, and a honeycomb-like (honeycomb core) member are preferably used. Skeletal spherical, mesh-like cylindrical members and the like can also be used. The filter bed 20 can be omitted.
[0021]
The electrolysis tank 4 will be described in more detail. A pair of or more electrodes 17 are disposed in the tank of the electrolysis tank 4, and the chloride ions contained in the sewage are oxidized at the anode to generate chlorine gas, which is then reacted with water. Generates chlorous acid. This hypochlorous acid oxidizes ammonia nitrogen, which occupies most of the nitrogen content in the influent sewage, to nitrogen gas and releases it into the atmosphere to remove nitrogen. The reaction formula at this time is assumed to be the following formula (1).
2NH ₄ ⁺ + 3HClO → N ₂ ↑ + 3HCl + 3H ₂ O + 2H ⁺ (1)
Since the reaction of the formula (1) is hardly affected by the water temperature, pH, amount of microorganisms, etc., it is stable even in the initial stage of operation where the microorganisms are not sufficiently grown or in the low water temperature period where the reaction rate of the microorganisms is reduced. Nitrogen can be removed.
[0022]
Here, the material of the electrode 17 includes, for example, a titanium electrode coated with platinum, a titanium electrode coated with one or more of iridium, palladium, ruthenium, rhodium, osmium and / or an oxide thereof, ferrite, carbon, carbon dioxide. Lead or the like can be used and is preferably insoluble.
[0023]
The shape of the electrode 17 is not particularly limited, and for example, a plate shape, a rod shape, a cylindrical shape, a mesh shape, a granular shape, or the like can be used according to the device shape. It is preferable to provide unevenness on the surface of the electrode 17 to increase the surface area. Further, the polarity of the electrode 17 may be fixed, but is preferably reversed periodically. Thereby, consumption of one electrode can be prevented and the lifetime of an electrode can be lengthened.
[0024]
The amount (molar amount) of hypochlorous acid supplied by electrolysis is 1 to 15 times, preferably 2 to 6 times in molar ratio to the amount of ammoniacal nitrogen flowing into the nitrogen removal tank 4. . When the amount of hypochlorous acid is less than 1 time, the performance of removing ammonia nitrogen from the influent wastewater is reduced, and when it is more than 15 times, the amount of hypochlorous acid is excessive and more than necessary. Leading to an increase in
[0025]
If the chloride ion concentration in the influent sewage is low, adding chloride such as sodium chloride or potassium chloride to the tank of the electrolysis tank 4 to increase the chloride ion concentration in the tank The amount of chlorous acid produced can be secured. Further, bromides such as sodium bromide and potassium bromide, and other halides may be added instead of chloride. In this case, hypobromite or hypohalous acid is generated by electrolysis, and nitrogen can be removed by a reaction similar to the above formula (1).
[0026]
When the amount of hypochlorous acid is excessive with respect to the amount of ammoniacal nitrogen in the influent sewage, it is consumed by the organic matter contained in the sewage or the sludge accumulated at the bottom of the anaerobic treatment tank 1, so that the organic matter is decomposed. Or it works favorably for sludge reduction.
[0027]
Anaerobic treatment tank 1 when hypochlorous acid is likely to be in excess of the amount of hypochlorous acid consumed by organic matter and bottom sediment sludge due to fluctuations in the concentration of ammoniacal nitrogen in the influent sewage In order to adsorb and remove the excess hypochlorous acid, the adsorbent such as activated carbon is provided on the outlet side of the electrolysis tank 4 to adsorb and decompose hypochlorous acid, or the electrolysis tank 4 Aeration is performed in the vicinity of the outlet side, and excess hypochlorous acid can be diffused into the air as chlorine gas or hydrogen chloride gas. In addition, an ammonia nitrogen concentration sensor is installed in the electrolysis tank 4 and the amount of hypochlorous acid generated is controlled by changing the current value (voltage value) of electrolysis according to the ammonia nitrogen concentration. Can do.
[0028]
It should be noted that physicochemical methods such as chemical oxidation (addition of an oxidizing agent), adsorption, and ion exchange can also be used as nitrogen removal means instead of electrolysis.
[0029]
FIG. 2 shows an anaerobic treatment tank (second embodiment) having a single tank structure provided with an oxidizing agent addition tank instead of the electrolysis tank. The description of the same parts as those in FIG. 1 is omitted, and next, an oxidant and its supply means according to the oxidant addition tank will be described. In addition, the chemical reaction formula of nitrogen removal when using an oxidizing agent is the same as the previous formula (1).
[0030]
The oxidant supply device 3 is provided above the oxidant addition tank 4 b or on the downstream side of the transfer pipe 9 for the surplus liquid 8 from the flow rate adjusting device 6. In the nitrogen removal tank 4b, an apparatus for stirring the liquid in the tank may be provided in order to efficiently perform the reaction (not shown).
[0031]
As oxidizing agents, hypochlorous acid, hypochlorite, hypobromite, hypobromite, isocyanurate, etc. can be supplied hypohalous acid, hypohalite, hypohalous acid. Substances can be used.
[0032]
As a method for supplying the oxidant, when a liquid oxidant is used, the oxidant tank is installed inside or outside the anaerobic treatment tank 1 and supplied into the oxidant addition tank 4b using a pump or the like.
The supply amount of the oxidant is 1 to 15 times, preferably 2 to 6 times in molar ratio with respect to the amount of ammoniacal nitrogen flowing into the oxidant addition tank 4b.
[0033]
Moreover, when using a solid oxidizing agent, the method etc. which install an oxidizing agent in the downstream of the transfer pipe | tube 9, make it melt | dissolve with the surplus water 8, and can flow in can be used. In this case, the supply amount of the oxidizing agent can be adjusted by the contact area between the oxidizing agent and the excess liquid 8.
[0034]
FIG. 3 shows an anaerobic treatment tank (third embodiment) having a single tank structure provided with an adsorbent filling tank instead of an electrolysis tank. The adsorbent filling tank 4 c is filled with an adsorbent and an ion exchanger 15, thereby adsorbing and removing ammonia nitrogen occupying most of the nitrogen content contained in the surplus liquid 8.
[0035]
Examples of the adsorbent include natural minerals such as zeolite, interlayer clay minerals, activated carbon, silicate, and the like, and any of them can be used.
[0036]
When the adsorbent or the ion exchanger 15 breaks through, the adsorbent or the ion exchanger 15 may be taken out and replaced with another adsorbent (or ion exchanger) 15 that is not broken through, or the adsorbent (or ions taken out) is removed. The exchanger 15) may be regenerated and filled.
[0037]
In order to prevent clogging of the packed bed of the adsorbent (or ion exchanger) 15, it is preferable to clean periodically. As an example of the cleaning method, there is a method in which a cleaning air diffuser pipe for sending air is provided below the adsorbent packed bed to perform air cleaning, and this cleaning wastewater is transferred to the anaerobic treatment tank 1 using a pump or the like ( (Not shown). This cleaning method is an example, and the present invention is not limited to this.
[0038]
FIG. 4 shows a two-chamber anaerobic treatment tank (fourth embodiment) equipped with an electrolysis tank of the present invention.
The first chamber 1a of the anaerobic treatment tank 1 is provided with a sewage inlet 2 at a height above the liquid level in the tank, and an electrolysis tank (nitrogen removal tank) 4 for removing nitrogen is provided in a section of the chamber. ing. Further, in the second chamber 1b, a discharge port 7 is provided in the tank body 24 on the opposite side to the sewage inflow port 2, and the L. W. A pump 5 for pumping up the liquid in the tank from the liquid level of L and a pump connected to the pump 5 for transferring a part of the pumped liquid to the outlet 7 and returning the excess liquid 8 into the tank of the nitrogen removing tank 4. A flow rate adjusting device 6 is provided. A baffle pipe 11 is provided around the pumping pump 5. A communication port 23 is provided in the partition 22 between the first chamber 1a and the second chamber 1b.
[0039]
The sewage (raw water) flows from the sewage inlet 2 into the first chamber 1a, where the solid matter that tends to settle in the sewage is first precipitated and separated. The sewage after the solid matter is precipitated and separated is transferred from the communication port 23 to the second chamber 1b. The sewage that has flowed into the second chamber 1b is further removed from the L. W. The pump is pumped up from the suction port 10 of the pump 5 provided in the L to the flow rate adjusting device 6, and a part of the liquid is discharged from the discharge port 7 to the outside of the tank, and the surplus liquid 8 is caused to flow into the electrolysis tank 4 to Nitrogen is removed by electrolysis.
[0040]
FIG. 5 is a two-chamber anaerobic treatment tank (fifth embodiment) equipped with an oxidant addition tank of the present invention. Since an oxidizing agent addition tank is used instead of the electrolysis tank, it is the same as the anaerobic treatment tank shown in FIG.
[0041]
FIG. 6 is a two-chamber anaerobic treatment tank (sixth embodiment) equipped with an adsorbent filling tank of the present invention. Since an adsorbent filling tank is used instead of the electrolysis tank, it is the same as the anaerobic treatment tank shown in FIG.
[0042]
FIG. 7 is an example of the sewage purification tank incorporating the anaerobic treatment tank of the first embodiment of the present invention, and FIG. 8 is an example of the sewage purification tank incorporating the anaerobic treatment tank of the fourth embodiment of the present invention.
Below, this sewage septic tank is demonstrated, referring FIG. The sewage septic tank has an anaerobic treatment tank 30 in which an anaerobic treatment tank second chamber 1b, a (aerobic) biological reaction chamber 31 and a filtration chamber 32 are juxtaposed in the downstream of the anaerobic treatment tank 1, and a disinfection tank 33. I have.
[0043]
Since the anaerobic treatment tank 1 is as described above, the description thereof is omitted.
The anaerobic treatment tank second chamber 1b is provided with a filter bed 20 below the liquid level. The shape of the filter bed 20 is not particularly limited, and plate-like members such as a loofah-like shape, a corrugated plate shape, and a porous shape, and a honeycomb-like (honeycomb core) member are preferably used. Skeletal spherical, mesh-like cylindrical members and the like can also be used.
[0044]
A reaction aeration member (aeration tube) 34 for aeration from the bottom is disposed in the (aerobic) biological reaction chamber 31 constituting the aerobic treatment tank 30, and air from the blower 35 is discharged. The biological reaction chamber 31 is formed with a biological reaction bed 31a filled with a carrier (a microbial carrier, a microorganism adhering material, and a contact material), and sewage is aerobically treated in the biological reaction bed 31a. Here, the biological reaction bed 31a may be a fluidized bed or a fixed bed. The shape of the microbial carrier can be various shapes such as plate, net plate, loofah, porous, cylinder, rod, skeleton sphere, string, and granular, irregular lump, cube, and fiber lump. What was processed into can be used. Examples of the base material include synthetic resin processed products such as polyvinyl chloride, polyester, polyvinylidene chloride, polyvinyl formal, polyurethane, and melamine resin, inorganic processed products such as ceramics and silica sand, and fossils such as anthracite. A processed product, activated carbon or the like having a specific gravity of about 1 or 1 or more, a polyolefin resin such as polyethylene or polypropylene, or a specific gravity of about 1 or 1 or less such as polystyrene can be used.
[0045]
A filtration bed 32a filled with a filter medium is formed in the filtration chamber 32, and the SS in the flowing liquid is captured there. As the filter medium to be filled, one that floats in the liquid can be used, but a sedimentation filter medium is preferable. Examples of sedimentary filter media include synthetic resin processed products such as polyvinyl chloride, polyester, polyvinylidene chloride, polyvinyl formal, polyurethane, and melamine resin, inorganic processed products such as ceramics and quartz sand, and fossil processing such as anthracite. Products, activated carbon, etc., with specific gravity of about 1 or more, or polyolefin resin such as polyethylene, polypropylene, etc., and those with a specific gravity of about 1 or more adjusted by adding fillers to polystyrene. It may be formed and processed into a lump shape, a cylindrical shape, a net shape, a rod shape, a fiber lump shape, or a porous shape.
Further, at the bottom of the filtration chamber 32, a cleaning air diffuser member (air diffuser pipe) 36 for backwashing the filter bed 32a is disposed, and this is connected to a blower 35 for supplying air.
[0046]
If the operation is continued, the filtration bed 32a is clogged with the accumulated SS, and therefore the filtration bed 32a is removed periodically or appropriately (reversely). In this cleaning, the air in the blower 35 is discharged from the cleaning air diffuser 36 to bubbling the filter bed 32a, and a part of the air in the blower 35 is also supplied to the cleaning drainage pump (air lift pump) 37. The peeled SS becomes cleaning wastewater together with the liquid in the tank, descends the filtration bed 32a, and returns to the anaerobic treatment tank 1 through the cleaning drainage discharge pipe 37a by the cleaning drainage pump 37. Since all of the liquid in the tank can be drawn out from the bottom of the filtration chamber 32 as washing wastewater, the filtration bed 32a is washed well. Note that an electric pump or the like can be used as the cleaning drainage pump 37. The filtration bed 32a is preferably washed when the water level of the anaerobic treatment tank 1 is LWL (that is, at midnight). This is because, in general households, sewage is rarely discharged at midnight, and the anaerobic treatment tank 1 becomes LW L.
[0047]
A circulation pump 41 that transfers the liquid that has passed through the filtration chamber 32 to the anaerobic treatment tank second chamber 1b is provided below the filtration chamber 32 or in the treated water tank 54. This is because when nitrate nitrogen is generated in the aerobic treatment tank 30, when this liquid is transferred to the anaerobic treatment tank second chamber 1b, it can be removed as nitrogen gas in the anaerobic treatment tank second chamber 1b.
In FIG. 4, an air lift pump type is shown for the circulation pump 41, but an intermittent metering pump or an electric pump by pneumatically feeding a sealed container can be used instead of the air lift pump type.
[0048]
The disinfection tank 33 is a tank that disinfects or sterilizes the advection liquid from the filtration chamber 32 by contacting the medicine barrel 38. The septic tank is provided with a manhole so that maintenance and management such as inspection and cleaning of each tank can be performed, and a manhole cover 39 is usually attached.
[0049]
Next, treatment of sewage in the sewage septic tank will be described. The sewage (raw water) enters the anaerobic treatment tank 1 from the sewage inflow port 2 and the solid matter is separated and precipitated. In the anaerobic treatment tank 1, the concentrated sludge (solid matter) that has settled is stored at the bottom of the tank, and the scum generated by anaerobic storage is stored at the top of the tank. The liquid advection from the anaerobic treatment tank 1 is performed by a pumping pump 5, and at this time, the advancing liquid is pumped up from a suction port 10 of L.W.L, and a predetermined amount is supplied from a flow control device 6 connected to the pumping pump 5. (A substantially constant amount) is transferred from the discharge port 7 to the anaerobic treatment tank second chamber 1b, and the surplus liquid 8 is transferred to the electrolysis tank 4 through the transfer pipe 9.
At this time, when the amount of raw water flowing in is larger than the transfer amount of the pump 5, the water level in the anaerobic treatment tank 1 rises from LWL to HWL, but the anaerobic treatment tank 1 Since the capacity of the flow rate adjusting unit 12 is designed not to exceed H.W.L, the water level does not normally rise above H.W.L.
[0050]
The advection liquid from the anaerobic treatment tank second chamber 1b enters the biological reaction chamber 31, and aerobically biodegrades organic matter in the advection liquid. At this time, since a substantially constant amount of advection liquid is loaded, stable processing is performed. The advection liquid from the biological reaction chamber 31 then enters the filtration chamber 32, where SS contained in the advection liquid is captured and removed, and in some cases, aerobic organisms are further dissolved by dissolved oxygen brought from the biological reaction chamber 31. Processing is performed. A part of the liquid that has passed through the filtration chamber 32 is transferred to the anaerobic treatment tank second chamber 1b by the circulation pump 41 to denitrify nitrate nitrogen contained in the liquid. The advection liquid that has passed through the filtration chamber 32 enters the disinfection tank 33 through the treated water tank 54 and is sterilized, and then discharged from the outlet 40 as treated water.
[0051]
【The invention's effect】
In the anaerobic treatment tank of the present invention, as described above, nitrogen in sewage can be removed almost without being affected by the water temperature, pH, amount of microorganisms, etc. Nitrogen can be stably removed even in winter when the speed is low.
In the sewage septic tank of the present invention, nitrogen in the influent sewage is effectively removed in the anaerobic septic tank (for the sewage septic tank), so that the capacity of the entire tank can be made compact and nitrogen can be removed more stably.
[Brief description of the drawings]
FIG. 1 is an anaerobic treatment tank (first embodiment) provided with an electrolysis tank of the present invention, in which (a) is a schematic plan view, and (b) is a schematic longitudinal sectional view taken along line AA in (a). .
FIG. 2 is an anaerobic treatment tank (second embodiment) provided with an oxidant addition tank according to the present invention, in which (a) is a schematic plan view, and (b) is a schematic longitudinal cross-sectional view taken along line AA in (a). Figure.
FIG. 3 is an anaerobic treatment tank (third embodiment) having an adsorbent filling tank according to the present invention, in which (a) is a schematic plan view, and (b) is a schematic longitudinal cross-sectional view taken along line AA in (a). Figure.
FIG. 4 is another anaerobic treatment tank (fourth embodiment) provided with an electrolysis tank of the present invention, in which (a) is a schematic plan view, and (b) is a schematic longitudinal section taken along line AA in (a). Plan view.
FIG. 5 is a schematic longitudinal sectional view of another anaerobic treatment tank (fifth embodiment) including an oxidizing agent addition tank according to the present invention.
FIG. 6 is a schematic longitudinal sectional view of another anaerobic treatment tank (sixth embodiment) including an adsorbent filling tank according to the present invention.
FIG. 7 is a schematic longitudinal sectional view of a sewage purification tank incorporating the anaerobic treatment tank of the first embodiment of the present invention.
FIG. 8 is a schematic longitudinal sectional view of a sewage purification tank incorporating an anaerobic treatment tank according to a fourth embodiment of the present invention.
FIG. 9 is a schematic longitudinal sectional view of a conventional sewage septic tank.
[Explanation of symbols]
1: Anaerobic treatment tank 1a (for sewage purification tank): (anaerobic treatment tank) first chamber 1b: (anaerobic treatment tank) second chamber 2: sewage inflow port 3: oxidant supply device 4: electrolysis tank (nitrogen removal) Tank)
4b: oxidizing agent addition tank (nitrogen removal tank)
4c: Adsorbent filling tank (nitrogen removal tank)
5: Pumping pump 6: Flow rate adjusting device 7: Discharge port 8: Surplus liquid 9: Transfer pipe 10: Suction port 11: Baffle pipe 12: Flow rate adjusting unit 13: Baffle pipe 14: Outlet 15: Adsorbent (or ion exchange) body)
17: Electrode 20: Filter bed 22: Partition 23: Communication port 24: Tank body 30: Aerobic treatment tank (31 + 32)
31: (aerobic) biological reaction chamber 31a: biological reaction bed 32: filtration chamber 32a: filtration bed 33: disinfection tank 34: aeration member for the reaction (aeration tube)
35: Blower 36: Air diffuser for cleaning (air diffuser)
37: Cleaning drainage pump (air lift pump)
37a: Washing drain discharge pipe 38: Medicine cylinder 39: Manhole cover 40: Outlet 41: Circulation pump 51: Anaerobic filter bed tank first chamber 52: Anaerobic filter bed tank second chamber 53: Biofiltration tank 54: Treated water tank 55 : Disinfection tank

Claims (5)

In the tank, a nitrogen removal tank that physically removes nitrogen,
A pump that pumps the liquid in the tank from the lowest liquid level,
The pump is connected to the pump, and a part of the pumped liquid is transferred to the outside of the tank, and a flow rate adjusting device for returning the excess liquid to the nitrogen removal tank is provided.
An anaerobic treatment tank for a sewage septic tank in which the liquid discharged from the nitrogen removal tank is circulated in the tank. The tank is divided into the first chamber and the second chamber from the upstream side.
A portion of the first chamber is provided with a nitrogen removal tank,
In the second chamber, a pump is connected to the pump to pump up the liquid in the tank from the lowest water level, and a part of the pumped liquid is transferred to the outside of the tank and surplus A flow rate adjusting device for returning the liquid to the nitrogen removal tank,
The anaerobic treatment tank according to claim 1, wherein the partition between the first chamber and the second chamber is provided with a communication port at a liquid level at the lowest water level. The anaerobic treatment tank according to claim 1 or 2, wherein the nitrogen removal tank is an electrolysis tank that removes nitrogen by electrolysis. The anaerobic treatment tank according to claim 1, wherein a filter bed is provided below the liquid level at the lowest water level in the tank. A sewage septic tank provided with the anaerobic processing tank in any one of Claims 1-3.

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