JP2011050902A - Water treatment system for sewage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water treatment system for sewage, capable of reducing the initial cost of a device, improving an organic matter decomposition performance in an aerobic reactor, and removing nitrogen. <P>SOLUTION: The water treatment system for sewage includes an upward flow type anaerobic reactor 11 for making organic waste water flow from the lower part to the upper part, and spiral aerobic treatment piping 12 wound around on the outer side of the anaerobic reactor 11, and is configured such that the flow-out water from the upper part of the anaerobic reactor 11 flows from the upper part to the lower part by natural flow-down through the aerobic treatment piping 12. A carrier for attaching microorganisms is provided inside the aerobic treatment piping 11, and aerobic treatment is performed by taking oxygen in the air from the surface part of a water flow. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wastewater treatment system for treating organic wastewater or sewage discharged in the manufacturing process of a food factory.

  As conventional water treatment technology, an anaerobic fixed bed or UASB (Upflow Anaerobic Sludge Blanket) method and other upstream anaerobic reactors are arranged in the front stage, and a downstream aerobic reactor is arranged in the rear stage. A system is known (Patent Document 1). Patent Document 1 has a configuration as shown in FIG. Reference numeral 1 in the figure denotes an anaerobic reactor, and organic waste water is supplied from the raw water pump 2. Connected to the anaerobic reactor 1 is an aerobic reactor 4 in which a filter bed 3 filled with a carrier (not shown) is arranged. A blower 5 is connected to the aerobic reactor 4. The anaerobic reactor 1 is connected to a gas processing tower 6 to which biogas is supplied from the anaerobic reactor 1. In FIG. 11, the solid line indicates the flow of water and the dotted line indicates the flow of gas.

  In this water treatment system, raw water is introduced into the anaerobic reactor 1, and organic substances in the raw water are decomposed in the anaerobic reactor 1 by the action of anaerobic microorganisms centering on methanogenic bacteria. This anaerobic treated water is introduced into the aerobic reactor 4 at the subsequent stage, and the organic matter that could not be decomposed by the anaerobic reactor 1 is decomposed by the action of an aerobic microorganism that uses oxygen to decompose the organic matter. .

  Anaerobic treatment is (1) low supply cost with no need for air supply, (2) low growth rate of microorganisms due to relatively slow growth rate of microorganisms (high disposal costs), (3) biogas There is an advantage that energy can be recovered using a boiler or generator.

  On the other hand, in the case of anaerobic treatment, in the generated biogas, gas such as hydrogen sulfide, which is a corrosive gas, and methane, which is a gas with a high greenhouse effect, is generated and cannot be released into the atmosphere. There is a problem that it is necessary. In addition, compared to aerobic treatment, the treatment performance of organic substances (BOD, COD, etc.) is inferior. For example, when the treatment target value is severe, such as BOD of treated water of 10 mg / L or less, the target water quality is not obtained with anaerobic treatment alone. There is a problem that it is difficult to achieve.

  On the other hand, aerobic treatment requires supply of oxygen compared to anaerobic treatment. Moreover, since there is much generation amount of sludge, although it costs, there exists a merit that a comparatively favorable water quality can be obtained. As for the aerobic treatment at the latter stage, as shown in FIG. 11, a method of supplying oxygen for use by aerobic microorganisms by sending air or oxygen gas into water by a blower 5 is the mainstream. However, in order to improve the above-described conventional technique, the present applicant has previously proposed a technique in which the watering section 7 is provided on the upper part of the aerobic reactor 4 as shown in FIG. 12 (Non-Patent Document 1). As described above, by using the water spray type aerobic reactor 4 for spraying the anaerobic treated water from the water sprinkling unit 7, significant energy saving can be achieved.

However, the aerobic reactor shown in FIG. 12 requires a large site area. Moreover, when watering is non-uniform | heterogenous, the part which does not process at all (dead space) arises, and processing efficiency worsens. Furthermore, when the amount of organisms attached to the carrier increases, the filter bed 3 becomes clogged, oxygen does not spread sufficiently, and the processing efficiency deteriorates.
On the other hand, in the anaerobic reactor, there is a problem that in winter when the outside air temperature decreases, the activity of the organism decreases and the processing performance deteriorates.

JP 2007-142077 A

  The present invention has been made in consideration of such circumstances, and it is possible to save space in an aerobic reactor, improve contact efficiency of aerobic microorganisms and treated water, and improve dissolution efficiency of oxygen in water used by aerobic microorganisms. The purpose of the present invention is to reduce the initial cost of the apparatus by improving the heat retention of the anaerobic reactor, improve the organic matter decomposition performance in the aerobic reactor, and provide a wastewater treatment system capable of removing nitrogen.

  The sludge water treatment system according to the present invention comprises an upward flow type anaerobic reactor for flowing organic waste water from the lower part to the upper part, and a pipe or water channel spirally wound around the outside of the anaerobic reactor. A wastewater treatment system in which effluent water from the upper part of the anaerobic reactor flows by natural flow from the upper part to the lower part through a spiral pipe or spiral water channel, and the spiral pipe or spiral A carrier for attaching microorganisms to the inside of the water channel is provided, and aerobic treatment is performed by taking in oxygen in the air from the surface portion of the water flow.

  ADVANTAGE OF THE INVENTION According to this invention, the reduction of the initial cost of an apparatus, the improvement of the organic substance decomposition | disassembly performance in an aerobic reactor, and the wastewater treatment system which can remove nitrogen can be provided.

Explanatory drawing of the water treatment system of the sewage which concerns on the 1st Embodiment of this invention. Explanatory drawing of the support | carrier arrange | positioned in the helical aerobic processing piping which is one structure of the water treatment system of FIG. An explanatory view of a carrier different from FIG. Explanatory drawing of the wastewater treatment system which concerns on the 2nd Embodiment of this invention. Explanatory drawing of the waste water treatment system which concerns on the 3rd Embodiment of this invention. Explanatory drawing which shows a part of aerobic water channel which is one structure of the water treatment system of FIG. Explanatory drawing of the waste water treatment system which concerns on the 4th Embodiment of this invention. Explanatory drawing of the wastewater treatment system which concerns on the 5th Embodiment of this invention. Explanatory drawing of the wastewater treatment system which concerns on the 6th Embodiment of this invention. Explanatory drawing of the waste water treatment system which concerns on the 7th Embodiment of this invention. Explanatory drawing of the conventional waste water treatment system. Explanatory drawing of the other conventional sewage water treatment system.

Hereinafter, the sludge water treatment system of the present invention will be described in more detail.
In the present invention, the carrier disposed inside the spiral pipe or the spiral water channel may be any material as long as microorganisms are easily attached thereto. Specifically, for example, a plastic hollow carrier made of, for example, a cylindrical hollow polypropylene of about 1 cm, polyethylene, vinylon, vinylidene chloride, etc. may be laid, or a sheet made of these materials under the pipe It may be one that has been spread. In addition, the material is not limited to plastic, and any material can be used as long as it is easy for microorganisms to adhere to it, such as ceramic, carbon fiber, metallic material, sponge, non-woven fabric, crushed stone, wood chip, activated carbon, etc. You can. The shape of the carrier is not limited to a cylindrical hollow shape or a sheet shape, but may be a square shape, or may be one in which a string-like contact material is tightened inside the pipe.

  In the present invention, the inclination of the spiral pipe is set to about 1/50 to 1/100 so that the water flow does not become too fast. The flow rate of the pipe can be obtained by Manning's formula or Kutta's formula ("Hydrologic Official Collection" published by Japan Society of Civil Engineers) The pipe diameter is determined so that the spiral pipe does not become full when the inflow rate of the raw water is the maximum designed flow rate. In addition, when the flow rate fluctuation | variation of raw | natural water is large, it is better to provide the flow control tank in the front | former part of an anaerobic reactor, or the back | latter stage of an anaerobic reactor.

Next, a wastewater treatment system according to an embodiment of the present invention will be described with reference to the drawings. Note that the present embodiment is not limited to the following description.
(First embodiment)
The sludge water treatment system according to the first embodiment will be described with reference to FIG. In this water treatment system, the effluent from the upper part of the anaerobic reactor is connected by a spiral aerobic treatment pipe (hereinafter referred to as aerobic treatment abolition) and flows from the upper part to the lower part by natural flow. .

  Reference numeral 11 in the figure denotes an upward flow type anaerobic reactor in which organic waste water flows from the lower part to the upper part. Here, examples of organic wastewater include wastewater from food factories, manure wastewater from pig farms, and municipal sewage. Upstream anaerobic reactors include, for example, anaerobic filter bed method, UASB method (Upflow Anaerobic Sludge Blanket), EGSB method (Expanded Granular Sludge Bed), There are IC reactor and anaerobic fluidized bed method. A spiral aerobic treatment pipe 12 is wound around the anaerobic reactor 11.

  As shown in FIG. 2, the aerobic treatment pipe 12 includes a cylindrical hollow polypropylene carrier 13 having a diameter of about 1 cm for adhering microorganisms therein, and takes in oxygen in the air from the surface portion of the water flow. Aerobic processing is performed. A raw water pump 14 is connected to the anaerobic reactor 11. A settling basin 15 is connected to the aerobic treatment pipe 12. A gas processing tower 16 to which biogas is supplied from the anaerobic reactor 11 is connected to the anaerobic reactor 11. In FIG. 1, the solid line indicates the flow of water and the dotted line indicates the flow of gas.

The operation of the water treatment system having such a configuration is as follows.
First, the organic waste water is introduced into the upward flow anaerobic reactor 11. In this anaerobic reactor 11, anaerobic processing is performed. In the anaerobic treatment, the organic matter in the organic wastewater is decomposed to methane gas by the action of hydrolyzing bacteria, acid-producing bacteria, and methanogens to remove most of the organic content in the wastewater. At this time, the biogas generated by the anaerobic treatment is a gas mainly containing methane and containing carbon dioxide. However, when the raw water contains a sulfur content, it is reduced by the action of sulfate-reducing bacteria, which are a kind of anaerobic bacteria, and hydrogen sulfide is produced in biogas.
This biogas is introduced into the gas treatment tower 16 and subjected to desulfurization treatment and deodorization treatment. This processing gas contains methane gas as a main component and is used as an energy source for boilers, gas engines, and the like.

On the other hand, the anaerobic treatment water overflows from the top. The overflow water is introduced into an aerobic treatment pipe 12 having a polypropylene carrier 13 laid in the lower part thereof as shown in FIG. 2, and when it falls along the aerobic treatment pipe 12 by natural flow, Oxygen is taken in from water and dissolved in water. The aerobic microorganisms attached to the carrier 13 use the oxygen dissolved in the water to decompose the organic matter that could not be removed by the anaerobic treatment to carbon dioxide. In addition, if biodegradable organic substances are completely removed at the upper and middle stages of the aerobic treatment pipe 12, nitrifying bacteria grow in the lower stage of the aerobic treatment pipe 12, and the treated water is caused by the action of the nitrifying bacteria. The nitrogen content (mostly ammonia nitrogen) is oxidized to nitrite (NO ₂ ⁻ ) or nitrate (NO ₃ ⁻ ).

  As shown in FIG. 1, the wastewater treatment system according to the present invention is wound around an anaerobic reactor 11 of an upward flow type in which organic wastewater flows from the lower part to the upper part, and outside the anaerobic reactor 11. It has a configuration in which a spiral aerobic treatment pipe 12 is provided, and effluent water from the upper part of the anaerobic reactor 11 flows along the aerobic treatment pipe 12 and flows by natural flow from the upper part to the lower part. The carrier 13 is provided inside, and the aerobic treatment is performed by taking in oxygen in the air from the surface portion of the water flow. Such a water treatment system has the following effects.

(1) Since the aerobic treatment is performed in the aerobic treatment pipe 12 wound around the anaerobic reactor 11, the space is saved compared to the case where a separate reactor is provided.
(2) Compared with the aerobic reactor of the type shown in FIG. 12 that sprinkles water from the top, the contact efficiency between the microorganisms adhering to the water and the carrier is higher, and the processing performance is higher.
(3) Compared with the aerobic reactor of the type shown in FIG. 12 that sprinkles water from the top, the contact efficiency between the microorganisms adhering to the water and the carrier is higher, and the treatment performance is higher.
(4) Since oxygen in the air can be taken in from the gas phase portion at the top of the aerobic treatment pipe 12, the oxygen dissolution efficiency is higher than that in the system as shown in FIG.

In addition, the fall of water temperature causes deterioration of the processing performance of the anaerobic reactor 11. Usually, in winter, the temperature of the wastewater is higher than the outside air. By winding the aerobic processing pipe 12 around the outside of the anaerobic reactor 11, the following effects are obtained.
(5) Since the area where the anaerobic reactor 11 directly touches the outside air is reduced, the anaerobic reactor 11 has a heat retaining effect, and the degradation of the processing performance of the anaerobic reactor 11 due to the temperature drop in the low temperature period can be alleviated.
(6) Since rain can be prevented from directly hitting the anaerobic reactor 11, it is possible to prevent a temperature drop of the anaerobic reactor 11 due to rain.

  In the first embodiment, as shown in FIG. 2, the case where a plurality of cylindrical hollow polypropylene carriers are spread in the lower part of the pipe is described, but not limited thereto, as shown in FIG. The case where the plastic sheet 17 made of the same material as that of the single body is disposed in the lower part of the aerobic processing pipe may be used.

(Second Embodiment)
The sewage water treatment system according to the second embodiment of the present invention will be described with reference to FIG. However, the same members as those in FIG. 1 and FIG.
Reference numeral 21 in the figure indicates a boiler. That is, the present water treatment system does not have to be an unheated system as shown in FIG. 1. For example, the methane gas generated as shown in FIG. 4 is burned by the boiler 21 and the anaerobic reactor 11 is heated. It is a thing. In the present water treatment system, if the anaerobic reactor 11 is a mesophilic methane bacterium, the activity becomes maximum at around 35 ° C., and the activity decreases as the temperature decreases.

  According to the second embodiment, since the heat generated by the anaerobic reactor 11 can be transferred to the aerobic processing pipe 12 wound outside, not only the performance of the anaerobic processing, The performance of aerobic treatment is also improved.

(Third embodiment)
The sewage water treatment system according to the third embodiment of the present invention will be described with reference to FIGS. Here, FIG. 5A is a schematic view of the main part of the water treatment system, and FIG. FIG. 6 is an explanatory diagram showing a part of an aerobic water channel which is one configuration of the water treatment system of FIG. However, the same members as those in FIG. 1 and FIG.
As shown in FIG. 5, the present embodiment is characterized in that a spiral aerobic water channel 31 is formed in the anaerobic reactor 11, and a weir 32 is disposed in the middle of the aerobic water channel 31. And In the water treatment system having such a configuration, water accumulates up to the position where the weir 32 exists, overflows the weir 32 as indicated by an arrow P, and flows into the lower spiral water channel.

According to the third embodiment, a spiral aerobic water channel 31 is provided in the anaerobic reactor 11, and the weir 32 is arranged in the middle of the aerobic water channel 31. Have
(1) The carrier 13 spread under the aerobic water channel 31 plays a role in preventing the carrier 13 from flowing downstream by the water flow.
(2) Since water is dispersed when it passes over the weir 32 and the contact surface of the gas and liquid becomes large, oxygen in the air is taken in at this time, and the dissolution efficiency of oxygen increases.
(3) Since the centrifugal force increases in the lower part of the spiral aerobic water channel 31, the flow velocity increases. By creating the weir 32, the flow rate can be reduced, and the contact time between the microorganisms adhering to the carrier 13 and water can be increased, so that the decomposition performance of organic matter can be improved.

(Fourth embodiment)
The sewage water treatment system according to the fourth embodiment of the present invention will be described with reference to FIG. However, the same members as those in FIGS. 1, 2, 5, and 6 are denoted by the same reference numerals, and the description thereof is omitted.
The water treatment system of the fourth embodiment has a configuration in which the aerobic water channels 31 a and 31 b are cut in the middle of the spiral aerobic water channel 31. Here, the treated water falls from the cut portion (stepped portion) 33 of the aerobic water channel 31a and falls into the lower spiral aerobic water channel 31b. In order to avoid the overflow of water to the outside, the width of the lower aerobic water channel 31b is designed to be slightly wider than that of the upper aerobic water channel 31a.

According to the fifth embodiment, when the water falls, the contact surface of the gas-liquid becomes large. At this time, oxygen in the air is taken in and the oxygen dissolution efficiency is increased.
Further, since the centrifugal force increases at the lower part of the continuous spiral aerobic water channel, the flow velocity becomes faster. Therefore, once the aerobic water channel 31 is cut as shown in FIG. 7 and the centrifugal force is relaxed, the water flow can be slowed, and the contact time between the microorganisms adhering to the carrier and water can be increased. Therefore, the decomposition performance of organic substances can be improved.
As another embodiment, the oxygen dissolution efficiency may be improved by providing a step in the pipe and increasing the gas-liquid contact surface at the step.

(Fifth embodiment)
The sewage water treatment system according to the fifth embodiment of the present invention will be described with reference to FIG. However, the same members as those in FIGS. 1, 2, 5, and 6 are denoted by the same reference numerals, and the description thereof is omitted.
In the water treatment system of the fifth embodiment, as shown in FIG. 8, meshes 34 are inserted at arbitrary intervals in a spiral aerobic water channel 31 to prevent the carrier 13 from flowing out. Here, the pore diameter of the mesh 34 is a diameter that does not clog and does not allow the carrier to flow downward, and is preferably as large as possible with a mesh width smaller than that of the carrier 13.

(Sixth embodiment)
The sewage water treatment system according to the sixth embodiment of the present invention will be described with reference to FIG. However, the same members as those in FIGS. 1, 2, 5, and 6 are denoted by the same reference numerals, and the description thereof is omitted.
In the water treatment system of the sixth embodiment, as shown in FIG. 9, the carrier 13 is placed in a mesh-like net 35, and weirs 32 are provided at arbitrary intervals so that the carrier 13 does not flow further downward. It is a thing.

(Seventh embodiment)
The sewage water treatment system according to the seventh embodiment of the present invention will be described with reference to FIG. However, the same members as those in FIGS. 1, 2, 5, and 6 are denoted by the same reference numerals, and the description thereof is omitted.
41 in the figure is a pipe connecting the pipe 42 for supplying treated water from the sedimentation basin 15 and the spiral aerobic treatment pipe 12 around the anaerobic reactor 11, and a circulation pump 43 is connected to the pipe 41. It is intervened. That is, the water treatment system of the eighth embodiment is configured to circulate the water treated by the aerobic microorganisms in the aerobic treatment pipe 12 to the front stage portion of the aerobic treatment pipe 12. In the lower part of the aerobic treatment pipe 12, the nitrogen content in the water to be treated is oxidized to nitrite (NO ₂ ⁻ ) or nitrate (NO ₃ ⁻ ) by the action of nitrifying bacteria. This water is circulated through the aerobic treatment pipe 12 by the circulation pump 43. The nitrite or nitrate contained in this water is denitrified by the action of denitrifying bacteria in the part of the channel where oxygen is insufficient (the part that is oxygen-free inside the microorganism attached to the carrier). Is decomposed to nitrogen gas. Thereby, nitrogen in water can be reduced.
According to the seventh embodiment, it is possible to remove nitrogen that is a causative substance of eutrophication at the treated water discharge destination.

In addition, although it has the structure which returns the water after a precipitation process in the water treatment system of FIG. 10, the water before flowing in into a sedimentation basin may be returned. Moreover, the structure which returns to the middle part of a water channel instead of returning to the upper end part of a water channel may be sufficient.
Furthermore, the pipe wound around the outside is made of a material that transmits light (transparent vinyl tube, etc.), so that algae can be propagated in the pipe, and it has the ability to remove nitrogen and phosphorus by photosynthesis. There may be.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

  DESCRIPTION OF SYMBOLS 11 ... Anaerobic reactor, 12 ... Spiral aerobic processing piping, 13 ... Carrier, 14 ... Raw water pump, 15 ... Sedimentation basin, 16 ... Gas processing tower, 17 ... Plastic carrier, 21 ... Boiler, 31 ... Aerobic Water channel, 32 ... weir, 33 ... stepped portion, 34 ... mesh, 35 ... mesh net, 41, 42 ... piping, 43 ... circulation pump.

Claims (6)

An upflow anaerobic reactor that flows organic wastewater from bottom to top;
Comprising a pipe or water channel spirally wound around the anaerobic reactor,
The sewage water treatment system is configured such that effluent water from the upper part of the anaerobic reactor flows through a spiral pipe or a spiral water channel and flows naturally from the upper part to the lower part,
A sewage water treatment system comprising a carrier for adhering microorganisms inside the spiral pipe or the spiral water channel, and performing aerobic treatment by taking oxygen in the air from a surface portion of a water flow.   The sewage water treatment system according to claim 1 or 2, wherein one or more weirs are provided in the spiral pipe or the spiral water channel.   The sewage water treatment system according to claim 1 or 2, wherein a stepped portion or a water suddenly dropping portion for enhancing a gas-liquid contact surface is arranged in a spiral pipe or a spiral water channel.   The sewage water treatment system according to any one of claims 1 to 4, wherein the carrier is prevented from flowing out by a mesh or a net-like net at an arbitrary interval in order to fix the carrier for adhering microorganisms. .   6. The wastewater treatment system according to claim 1, further comprising a circulation unit that returns water at a lower end portion of the spiral pipe or the spiral water channel to an upper end portion or an intermediate portion thereof.   The sewage water according to any one of claims 1 to 6, which has a function of removing nitrogen and phosphorus by a photosynthesis reaction by using a pipe wound around the outside of the anaerobic reactor as a light transmitting material. Processing system.

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