WO2018096583A1

WO2018096583A1 - Microorganism reaction vessel and method for treating wastewater

Info

Publication number: WO2018096583A1
Application number: PCT/JP2016/084606
Authority: WO
Inventors: 藤野　清治
Original assignee: 日本アルシー株式会社
Priority date: 2016-11-22
Filing date: 2016-11-22
Publication date: 2018-05-31
Also published as: TW201819314A

Abstract

The purpose of the present invention is to provide a microorganism reaction vessel that can be installed in part of a hotel or other lodging facility and is capable of reusing treated wastewater, and a method for treating wastewater in which said microorganism reaction vessel is used. The present invention is provided with: an outer vessel 2; a cylindrical inner vessel 3 that is disposed inside the outer vessel and that has a vertical opening part; a circulation rate control device 4 that is provided to an upper part of the cylindrical inner vessel and that controls the in-vessel circulation rate of to-be-treated water; a cylindrical control plate 5 disposed such that an open lower surface thereof is near an inclined surface on the outer periphery of the upper part of the cylindrical inner vessel, the cylindrical control plate allowing precipitation of contaminants; to-be-treated water quality measurement devices 6 provided to the outer side and inner side of the cylindrical inner vessel; a raw water supply port 10 provided to a circulation path of the to-be-treated water circulating in the outer vessel and inner vessel, and a treated water discharge port 11 provided to an upper part of the outer vessel; a precipitation fixation prevention device 12 that prevents the precipitated contaminants from becoming fixed by precipitation; and a membrane separation device 14 that is provided within or outside of the microorganism reaction vessel and that is capable of filtering treated water.

Description

Microbial reaction tank and waste water treatment method

The present invention relates to a microorganism reaction tank and a wastewater treatment method using the microorganism reaction tank.

Wastewater containing high concentrations of nitrogen, phosphorus, organic substances and other pollutants that increase biochemical oxygen demand (hereinafter referred to as BOD) and suspended solids concentration (hereinafter referred to as SS) can cause river pollution and red tides. It is a cause of environmental pollution. Conventionally, a so-called modified Bernard method, which is one of aerobic and anaerobic circulation methods, is known as a method for treating wastewater containing such high-concentration pollutants. This method uses the first denitrification tank and the second denitrification tank located before and after the first nitrification tank in the activated sludge treatment process in order to reuse the alkali liberated during the denitrification reaction in the nitrification reaction. This is a method in which the nitrification tank is divided into two stages, a second nitrification tank is provided after the second denitrification tank, and the mixed liquid flowing out from the first and second nitrification tanks is circulated to the first denitrification tank.

However, the wastewater treatment by this method has the following problems.
(1) Since high-concentration ammoniacal nitrogen itself has bactericidal properties, it often inhibits the activity of activated sludge in the activated sludge treatment process. For this reason, the activated sludge treatment becomes insufficient.
(2) In the so-called modified Bernard method or the like, the hydrogen ion concentration (hereinafter referred to as pH) decreases as the nitrification reaction proceeds in the nitrification tank. However, since the nitrification reaction depends on the pH, the nitrification reaction becomes slower when the pH decreases. As a result, the activated sludge treatment becomes insufficient, and phosphorus removal and the like become insufficient.
(3) If the activated sludge treatment is insufficient and the denitrification reaction is delayed, the residual ammonia, nitrate ion, nitrite ion concentration, etc. will increase, resulting in an increase in BOD depending on these nitrogen compounds, resulting in insufficient wastewater treatment. Become.
(4) High-concentration pollutant-containing wastewater requires high-concentration activated sludge, which inevitably tends to increase the concentration of suspended activated sludge (hereinafter referred to as MLSS). Therefore, it becomes difficult to supply oxygen, and stirring of activated sludge and solid-liquid separation in a precipitation tank become difficult.
(5) Despite the low organic pollutant concentration, when denitrification and denitration of wastewater having a high nitrogen component is performed by activated sludge treatment, problems such as pH reduction and sludge floating due to denitrification occur.

In order to cope with the above method, the present inventor has a microorganism reaction tank capable of efficiently performing activated sludge treatment of waste water containing pollutants such as high concentration nitrogen components, phosphorus components, and organic substances, and A wastewater treatment method using the same has been proposed (Patent Document 1). This microbial reaction tank is provided with an inner tank having a nitrification reaction part and a denitrification reaction part connected to each other by turbine blades.
In addition, as an improved version of the microbial reaction tank described in Patent Document 1, anaerobic / aerobic microbial treatment of treated raw water can be continuously performed while maintaining a high circulation rate in the tank, and the cylindrical inner tank can be simplified. A microorganism reaction tank has been proposed that can be easily installed even if the capacity of the reaction tank is increased by adopting a simple shape (Patent Document 2).

JP-A-11-128987 WO2013 / 132608

However, if the microbial reaction tank is to be installed in the wastewater treatment of a hotel or other accommodation facility that discharges a large amount of raw water, the microbial reaction tank itself must be downsized and the treated wastewater must be reused. However, the improved type described in Patent Document 2 has a problem that it cannot be dealt with.
The present invention has been made to cope with such a problem. A microbial reaction tank that can be installed in a part of an accommodation facility such as a hotel and can reuse treated wastewater, and a microbial reaction tank therefor. The purpose is to provide the wastewater treatment method used.

The microorganism reaction tank of the present invention includes an outer tank, a cylindrical inner tank disposed inside the outer tank and having openings on the upper and lower sides, and an in-tank circulation of water to be treated provided on the upper part of the cylindrical inner tank. A circulation rate control device for controlling the rate, a cylindrical control plate for allowing sludge to settle by placing an open lower surface close to the inclined surface of the upper outer periphery of the cylindrical inner tub, and A device for measuring the quality of water to be treated provided outside and inside the cylindrical inner tank, a raw water supply port provided in a circulation path of the water to be treated that circulates in the outer tank and the inner tank, and an upper part of the outer tank. And a treated water discharge port.
This microbial reactor has the following characteristics.
(1) The said cylindrical inner tank is divided | segmented into the cylinder upper part and the cylinder lower part with the partition which has a communicating hole in center part.
(2) The upper part of the cylinder has a truncated cone-shaped top part with an open top and bottom surface, the inclination angle of the height direction cross section passing through the center of the truncated cone is 40 degrees to 60 degrees, and the upper part of the cylinder A plurality of air blowing openings are provided around the communication hole and in the peripheral edge of the partition wall, and are provided in the cylindrical inner tank by a plurality of support columns that are fixed and erected on a base that is a bottom surface of the outer tank. Moreover, it is the aerobic microorganism processing tank arrange | positioned inside the outer tank because the said partition is supported.
(3) The cylindrical lower part is an anaerobic microorganism treatment tank having an opening on the bottom surface.
(4) The raw water supply ports are a plurality of discharge ports or slits provided in an annular raw water supply unit disposed below the opening of the anaerobic microorganism treatment tank.
(5) At least one settling-immobilization preventing device selected from a scraper and a stirring flow generator for preventing settling of the settled sludge is provided in the lower part of the outer tank where the sludge settles.
(6) Detect at least one measurement value selected from the pH, redox potential (hereinafter referred to as ORP), and dissolved oxygen content (hereinafter referred to as DO) measured by the treated water quality measuring device. Means and means for controlling the circulation rate in the tank to be treated to 3 to 20 in accordance with the measured value detected by the means are provided in the circulation rate control device. It is a device that controls at least one amount selected from the opening / closing of the adjustment valve, the rotation or vertical movement of the liquid level adjustment control plate, and the amount of air blown from the air blowing port. Here, the to-be-processed water circulation rate in a reaction tank means the quantity defined by following Formula.

Rate of treated water circulation = amount of treated water discharged from the upper part of the inner tank (m ³ / day) / raw water supply (m ³ / day)

(7) A membrane separation device is provided in the microorganism reaction tank or outside the tank and capable of filtering treated water.
(8) The raw water supplied from the raw water supply port passes through the inside of the cylindrical inner tank together with the activated sludge, the outer peripheral surface of the cylindrical inner tank, and the activated sludge settled in the lower part of the outer tank. The anaerobic microorganism treatment and the aerobic microorganism treatment are continuously performed by circulating the gas.

The wastewater treatment method of the present invention is a circulating wastewater treatment method including an activated sludge treatment step using the microorganism reaction tank of the present invention.
This waste water treatment method includes the following steps.
(1) supplying wastewater discharged from the sewage discharge source to the raw water aeration control tank;
(2) In the raw water aeration adjusting tank, after adjusting the aeration so that the oxidation-reduction potential becomes a positive value, supplying the adjusted treated raw water to the microorganism reaction tank;
(3) an activated sludge treatment step in which anaerobic and aerobic microorganism treatment is continuously performed in the microorganism reaction tank;
(4) supplying the sludge generated from the microorganism reaction tank to the raw water aeration adjustment tank;
(5) A step of returning the treated water introduced into the membrane separation apparatus and separated by the apparatus to the wastewater discharge source.

In the microbial reaction tank of the present invention, a cylindrical inner tank disposed inside is divided into an upper part of the cylinder and a lower part of the cylinder by a partition wall having a communication hole in the center, and therefore contains a high-concentration pollutant. Anaerobic / aerobic microbial treatment of raw water can be continuously performed while maintaining a high circulation rate in the tank. Moreover, since the settling immobilization prevention device is provided, sludge can be prevented from being settled and fixed in the lower part of the microorganism reaction tank. As a result, anaerobic / aerobic microbial treatment of raw water containing high-concentration pollutants can be continuously performed while maintaining a high circulation rate in the tank, and the cylindrical inner tank can be made into a simple shape. In addition, even when the capacity of the reaction tank is increased, the microbial reaction tank can be easily installed. Furthermore, since the membrane separation device capable of filtering the treated water is provided, the amount of the treatment liquid in the microorganism reaction tank can be reduced, so that the microorganism reaction tank can be further miniaturized and the treated water can be reused as domestic water.

In the wastewater treatment method of the present invention, the above-described miniaturized microbial reaction tank can be easily installed in a site such as an accommodation facility, and the circulation of the present invention includes a membrane separation device capable of filtering treated water. By using the mold wastewater treatment method, wastewater discharged from accommodation facilities can be reused as domestic water. In addition, effective use of water resources can be achieved.

It is sectional drawing of a microbial reaction tank. It is a top view shown about the arrangement position of a membrane separator. It is sectional drawing of the microorganisms reaction tank provided with the scraper. It is sectional drawing of the microorganisms reaction tank provided with the mobile fluid spray nozzle. It is sectional drawing of the microorganisms reaction tank provided with the fixed fluid spray nozzle. It is a figure which shows the to-be-processed water and the circulation path | route of activated sludge in a microbial reaction tank. It is a block diagram of the circulation type waste water treatment method of the present invention.

The microbial reaction tank of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view of a microbial reaction tank.
The microbial reaction tank 1 includes an outer tank 2, a cylindrical inner tank 3 disposed in the outer tank 2, a circulation rate control device 4 provided on the upper part of the cylindrical inner tank 3, and a cylindrical shape The cylindrical control board 5 provided in the outer peripheral side of the inner tank 3 and the to-be-processed water quality measuring apparatus 6 are comprised. In addition, the sludge extraction port 13 can be provided.
In the present invention, the water tank volume of the microbial treatment equipment is not limited, and it can be applied from a small scale to a large scale, but the effect is remarkably exhibited when the microbial reaction tank 1 is 20 m ³ or more. It is preferably applied to a microbial reactor having an internal volume of 30 to 6000 m ³ . When the volume of the treatment tank exceeds 6000 m ³ , it becomes difficult to create a circulating flow. Moreover, in the case of a small scale of less than 20 m ³ , the advantage of circulating the sludge up and down in the microorganism reaction tank 1 is reduced.

The outer tub 2 has a true cylindrical appearance including a cylindrical side surface 2b and an upper surface portion 2c on a base 2a serving as a bottom surface. A rotating shaft 7 for attaching a stirring blade or the like is provided at the center of the cylinder. The rotary shaft 7 is rotatably fixed by a frame 2d provided at the center of the circle of the base 2a and a bearing 2e provided at the center of the circle of the upper surface portion 2c. The rotating shaft 7 is rotated by the driving device 2f. The upper surface portion 2c fixes the rotating shaft 7 rotatably, and holds the cylindrical inner tank 3 with a support or the like.
A raw water supply port 10 is provided at the bottom of the outer tub 2 and below the cylindrical inner tub 3. The raw water supply port 10 includes a plurality of discharge ports 10b or slits provided in the annular raw water supply unit 10a, which are disposed below the lower opening 3f of the cylindrical inner tank 3. By disposing the raw water supply port 10 in this way, the anaerobic sludge is sufficiently stirred. The raw water supply port 10 can be provided in addition to the lower part of the cylindrical inner tank 3 as long as it is a circulation path of the water to be treated.
Moreover, the upper part of the outer tank 2 is provided with a treated water discharge port 11 for discharging purified treated water and a membrane separator 14 capable of filtering the treated water, and sedimentation of settled sludge is performed on the inner and outer surfaces of the outer tank. A settling immobilization prevention device 12 is provided for preventing immobilization.

The arrangement position of the membrane separation device 14 is shown in FIG. A plurality of membrane separation devices 14 shown in FIG. 2 are preferably arranged as a submerged membrane separation device that is used by being immersed in a purified treated water region in the upper part of the outer tub 2. The membrane separation device 14 in the present invention is arranged to further purify treated water rather than separating activated sludge and treated water in a so-called membrane separation activated sludge method (hereinafter also referred to as MBR method). As will be described later, in the present invention, the activated sludge and the treated water include an inclined surface 3h formed in the upper part 3c of the cylindrical inner tank and an inclined surface 3h set to 40 to 60 degrees, and the inclined surface 3h. The sludge sedimentation is further accelerated by the boycott effect due to the interaction with the lower surface 5a of the cylindrical control plate 5 disposed in close proximity to each other. Therefore, there is almost no activated sludge in the purified treated water region in the upper part of the outer tank 2 where the membrane separation device 14 is disposed. The membrane separation device 14 can be separately provided outside the microorganism reaction tank 1. In that case, the discharge water discharged from the treated water discharge port 11 can be filtered and circulated by a membrane separation device provided outside the microorganism reaction tank.

In the submerged membrane separator 14 arranged in the treated water region, a plurality of membrane elements 14b are arranged in the frame body 14a. A part 14c of the frame 14a has an opening, and the treated water in the microbial reaction tank flows into the opening through the membrane element 14b and becomes treated water that can be used as domestic water. It is discharged from 14d. An air diffuser (not shown) can be disposed around the membrane element 14b, and a part of the air sent to the air blowing port 8 can be used. Further, an ultrasonic vibration device can be used in combination. The submerged membrane separator 14 can use not only a flat plate type but also a hollow fiber membrane module.

The material of the membrane element 14b is polyethylene, polypropylene, polysulfone, polyethersulfone, polyvinyl alcohol, cellulose acetate, polyacrylonitrile, chlorinated polyethylene, polyvinylidene fluoride, polyvinyl fluoride, polytetrafluoroethyne, aliphatic polyamide, aromatic Group polyamide, polyethylene terephthalate, and composite films thereof.
As the membrane element 14b, a known MF membrane (microfiltration membrane: pore size: 0.01 μm to 10 μm) or UF membrane (ultrafiltration membrane: pore size: 0.001 μm to 0.01 μm) can be used.

A settling immobilization preventing device 12 for preventing settling of settled sludge will be described below with reference to FIGS.
Examples of the anti-settling device 12 include a scraper or a stirring flow generation device, and may be a single device or a combination thereof.
(1) Scraper provided on the inner wall of the lower part of the outer tank in which sludge settles An example of a cross-sectional view of a microorganism reaction tank provided with a scraper is shown in FIG. A moving device 12e capable of moving along the upper peripheral edge of the outer tub is attached to the upper peripheral edge of the outer tub, and a scraper 12d is attached to the tip of the moving device 12e. By moving the scraper 12d along the inner wall of the lower part of the outer tank, the settled sludge is loosened to provide fluidity. Sludge that is given fluidity will not settle and settle. The movement of the scraper 12d may be a moving device 12e capable of traveling along the upper peripheral edge of the outer tub, or may be a mechanical rotary moving device that rotates on the upper peripheral edge of the outer tub.

(2) Stirring flow generator for generating sludge stirring flow along the inner wall of the lower part of the outer tub FIG. 4 and FIG. 4 is a cross-sectional view of a microorganism reaction tank provided with a movable fluid spray nozzle that sprays fluid while moving on the inclined surface of the inner wall, and FIG. 5 is fixed to the inclined surface of the inner wall at a predetermined interval. It is a figure which shows the example of the fluid spray nozzle.
The nozzle 12f arranged on the inclined surface at the lower part of the inner wall of the outer tank shown in FIG. 4 sprays the fluid sent from the blower or pump mounted on the moving device 12e attached to the upper peripheral edge of the outer tank to the accumulated sludge. be able to. Examples of the fluid include air, water, and sludge. By spraying a fluid from the nozzle 12f on the accumulated sludge, it is possible to impart fluidity to the deposited sludge and prevent sedimentation and fixation of the sludge.
A plurality of nozzles 12g shown in FIG. 5 are arranged at a predetermined interval in the circumferential direction of the inclined surface of the lower part of the inner wall of the outer tank where fluid can be sprayed uniformly on the sludge accumulated in advance. In addition, a plurality of them are arranged at a predetermined interval in the inclination direction of the inclined surface of the lower part of the inner wall of the outer tank. By continuously or intermittently spraying the fluid from the plurality of nozzles 12g, fluidity can be imparted to the deposited sludge to prevent the sludge from being settled and fixed. It is important that the fixed nozzle 12g has a structure in which a nozzle is provided above the inclined surface of the lower inner wall of the outer tank and the piping is installed in the direction of the circulating flow so as not to inhibit the circulating flow of sludge as much as possible. In addition, it can be set as the discharge pump provided with the suction nozzle which sucks the sludge settled in the outer tank lower part, and the discharge port which discharges the sucked sludge in an anaerobic microorganisms processing tank instead of the nozzle 12g. When the discharge pump is fixedly arranged, it is important to install the discharge pump in a method that does not hinder the sludge circulation flow. For example, all the pump pipes are installed in parallel with the flow direction of the sludge circulation.

The cylindrical inner tub 3 is disposed in the outer tub provided with the settling and fixing prevention device 12.
As shown in FIGS. 1 and 2, the cylindrical inner tank 3 having a substantially circular cross section is divided into a cylindrical upper part 3c and a cylindrical lower part 3d by a partition wall 3a. A communication hole 3b is provided in the central portion of the partition wall 3a to connect the cylindrical upper part 3c and the cylindrical lower part 3d.
Even when the volume of the microorganism reaction tank is increased due to the presence of the partition wall 3a, the cylindrical upper part 3c and the cylindrical lower part 3d are sufficiently separated, and activated sludge treatment can be performed in each tank. The aerobic microorganism treatment reaction can be sufficiently performed in the cylindrical upper portion 3c, and the anaerobic microorganism treatment reaction can be sufficiently performed in the cylindrical lower portion 3d. When the area of the partition wall 3a becomes large, it is reinforced with a support member 3g or the like.
The communication hole 3b has a diameter that allows the activated sludge treated with anaerobic microorganisms to move from the cylindrical lower part 3d to the cylindrical upper part 3c, which is an aerobic microorganism treatment part. The diameter of the communication hole 3b is adjusted by the volume of the microorganism reaction tank, the nature and amount of raw water to be treated, and the like.

The cylindrical upper part 3c has a truncated cone-shaped top with an open top and bottom. That is, it is a shape in which the tip of the cylindrical portion is reduced in diameter by a predetermined angle in the height direction. The inclination angle of the cross section in the height direction passing through the center of the truncated cone is 40 to 60 degrees, preferably 45 degrees. By making the inclination angle within this range, the sludge contained in the water to be treated discharged from the upper part of the aerobic tank flows down the frustoconical outer surface, so that the sludge tends to aggregate due to the so-called boycott effect, enabling rapid forced sedimentation of the sludge. Become. Moreover, when sludge aggregates, separation of the sludge and the purified treated water becomes easy. Therefore, there is no sludge in the region where the membrane separation device 14 is arranged.

The cylindrical upper portion 3c is an aerobic microorganism treatment tank in which

air blowing ports

8 and 8a are provided. The air blowing port 8 is provided around the central shaft 7 and around the communication hole 3b, and can be fixed on the partition wall 3a by a support pillar (not shown). It is preferable that the air outlet of the air inlet 8 is preferably disposed downward because it can contribute to the agitation of the water to be treated and sludge in the aerobic tank.
The air blowing port 8a has a plurality of air holes 8c or air blowing portions 8b provided in the air blowing portion 8b. It can be made into the slit formed in the upper surface or side surface of this.
The amount of water to be treated is varied within the range of 3 to 20 without using a circulation pump, depending on the amount of air blown from the

air blowing ports

8 and 8a and the control amount of the circulation rate control device described later. Can do. Thereby, the aerobic microorganism treatment by an appropriate nitrification condition and the anaerobic microorganism treatment by an appropriate denitrification condition can be easily set. Furthermore, because the sludge solid-liquid separation is made very efficient by the forced sedimentation principle on the outer peripheral surface of the aerobic microorganism treatment tank having the above-mentioned inclination angle, the aerobic / anaerobic microorganism treatment reaction is efficiently carried out in the same vertical tank. Can be done.
In the aerobic tank, an alkali supply port or an acid supply port (not shown) can be provided.

The cylindrical lower part 3d is an anaerobic microorganism treatment tank having a volume that is 1/10 to 1 times the volume of the upper part of the cylinder. Within this volume range, for example, an aerobic microbial treatment reaction and an anaerobic microbial treatment reaction of raw water containing a high-concentration nitrogen-containing pollutant can be efficiently performed. In the anaerobic microorganism treatment tank, a denitrifying nutrient supply port (not shown) can be provided.
In addition, when there are few hydrogen donors in the raw water and nitrogen is denitrified by supplying a nitrogen donor such as methanol or acetic acid, the volume of the anaerobic microorganism treatment tank is made larger than that of the aerobic microorganism treatment tank. It is preferable.
The shape of the cylindrical lower portion 3d is a shape having an inverted truncated cone shape having an opening 3f having a larger area than the opening 3e of the cylindrical upper portion 3c at the lower portion of the cylinder. That is, it is a shape in which the tip of the cylindrical portion is reduced in diameter by a predetermined angle in the lower direction. By increasing the area of the opening 3f, the sludge can be easily stirred in the anaerobic microorganism treatment tank.
When the shape of the cylindrical lower portion 3d is the inverted truncated cone shape, it is preferable that the lower inner surface 2g of the outer tub 2 has the same angle as the predetermined angle because it is possible to prevent sludge from being settled and fixed.

The cylindrical inner tank 3 is provided with a stirring device for sufficiently carrying out the treatment reaction between the water to be treated and the activated sludge in the aerobic microorganism treatment tank as the cylinder upper part 3c and in the anaerobic microorganism treatment tank as the cylinder lower part 3d. Is provided.
The stirring device is preferably a

stirring blade

7a or 7b fixed to a rotary shaft 7 attached to the center of the cylindrical inner tank 3. The stirring blade 7a is preferably provided in the cylindrical upper part 3c, and a turbine blade capable of sufficiently performing the aerobic microorganism treatment reaction is preferable. In addition to the turbine blade, any shape can be used as long as the number of rotations at which the aeration performance is not significantly lowered by the amount of air blown is relatively small and the air and water can be mixed.
Any stirring blade can be used as long as the stirring blade 7b is provided in the cylindrical lower part 3d and can sufficiently perform the anaerobic microorganism treatment reaction, but a turbine blade or a propeller blade is preferable.

The partition wall 3 a provided in the cylindrical inner tub 3 is supported by a plurality of support columns 9 that are fixed and erected on the base 2 a that is the bottom surface of the outer tub 2. Due to the buffer effect of the plurality of support columns 9, the stirring flow in the anaerobic microorganism treatment tank is disturbed, and the stirring in the tank is efficiently performed.
The cylindrical inner tank 3 is held in the outer tank by a support by the support column 9 and a support tool bridged to the upper part of the outer tank 2.

A circulation rate control device 4 for controlling the circulation rate of the water to be treated in the reaction tank is provided on the upper part of the cylindrical inner tank 3. The circulation rate control device 4 includes a liquid level adjustment valve and / or liquid level adjustment control plates 4a and 4b provided on a concentric cylinder. The liquid level adjustment control plates 4a and 4b are formed with longitudinal slits in both or one of them. Specifically, the control of the circulation rate in the reaction tank of the water to be treated is performed by opening and closing the liquid level adjustment control plates 4a and 4b in which longitudinal slits are formed on both sides, or the liquid level adjustment control plate 4a. And 4b are formed by mutual vertical movement of a liquid level adjustment control plate in which a vertical slit is formed on one side and no slit is formed on the other side. The level of the water to be treated is lowest when the liquid level control valve is fully opened, when the slit of the liquid level control plate is fully opened, or when the liquid level control plate without slits is moved up and down. The water level is indicated by A.

The control of the circulation rate in the reaction tank can also be controlled by the amount of air blown from the air blowing port 8 and / or 8a. Increasing the amount of air blown increases the circulation rate. It is also possible to combine opening / closing of the liquid level control valve and air amount control.

As the anaerobic microorganism treatment tank and aerobic microorganism treatment tank increase in size, maintaining the circulating flow rate of sludge is not sufficient with aeration air alone, or harmful effects due to excessive air blowing may occur. There is. In preparation for such a case, the air inlet shown in FIG. Due to the air blowing port 8a having poor aeration efficiency, there is an advantage that the adjustment of the air blowing amount and the ORP is much easier to adjust. For example, the air blowing port 8a is provided with an air blowing portion 8b having an annular shape in plan view, which is in communication with an external blower or the like around the stirring blade 7a in an aerobic portion which is the upper surface of the partition wall 3a. The part 8b is provided with a hole or a slit. This not only simply increases the amount of air, but also exhibits a baffle effect of the stirring blade 7a, and exhibits a synergistic effect that allows efficient stirring.

By adjusting the opening and closing of the liquid level control valve and / or the air blowing amount, the circulation rate of the water to be treated can be changed without using a pump. As will be described later, the water to be treated is treated from the aerobic microorganism treatment tank 3c to the anaerobic microorganism treatment tank 3d through the cylindrical control plate 5 disposed outside the tank, and further from the anaerobic microorganism treatment tank 3d. By circulating to the tank 3c, denitrification, dephosphorization, etc. are performed. Therefore, optimal denitrification, dephosphorization, etc. can be performed by controlling the circulation rate of the water to be treated based on a predetermined control program according to the detected value.

A cylindrical control plate 5 is disposed on the upper outer periphery of the cylindrical inner tank 3. The cylindrical control plate 5 is a cylinder whose upper and lower surfaces are open, and the lower surface 5 a of the cylindrical control plate 5 is disposed close to the inclined surface 3 h of the cylindrical inner tank 3. A sludge sedimentation portion is formed in the inclined surface portion disposed close to the slurry, and sludge is concentrated and treated water is separated. Moreover, the rapid forced sedimentation of sludge is attained by arrange | positioning the lower surface 5a close. It is preferable that the size of the distance of the lower surface 5a with respect to the inclined surface 3h of the cylindrical inner tank 3 can be adjusted by the type and amount of sludge. Moreover, the shape of the cylindrical control plate 5 can be a right cylindrical shape in which the opening surfaces of the upper surface and the lower surface have the same area, or an inverted truncated cone shape in which the opening area of the upper surface is larger than the opening area of the lower surface.
In the microorganism reaction tank, a water quality measuring device 6 to be treated is provided inside and outside the cylindrical inner tank 2. This to-be-processed water quality measuring apparatus 6 is an apparatus which measures pH, ORP, and DO of to-be-processed water.

The circulation rate of water to be treated in the microbial reaction tank of the present invention is 3 to 20, preferably 5 to 20. If the circulation rate of the treated water is less than 3, the aerobic microbial treatment reaction is more likely to occur, and if it exceeds 20, the balance between the aerobic microbial treatment reaction and the anaerobic microbial treatment reaction is lost, and the raw water is denitrified and dehydrated. Unable to perform phosphorus. That is, by setting the treated water circulation rate within this range, the ORP of the treated water measured by the treated water quality measuring device is −10 mV or less, preferably −50 mV or less, and the aerobic microorganism treatment in the anaerobic microorganism treatment reaction tank. In the reaction vessel, it can be maintained at +10 mV or more, preferably +100 mV or more. As a result, the aerobic microorganism treatment reaction and the anaerobic microorganism treatment reaction are sufficiently performed, and denitrification and dephosphorization are continuously performed. Under such conditions, the pH in the aerobic microorganism treatment reaction tank is in the range of 4.5 to 8.5, preferably 5.5 to 7.5.

The wastewater treatment method using the microbial reaction tank 1 is a wastewater treatment method for treating raw water by a treatment process including an activated sludge treatment process, and the activated sludge treatment process includes a sludge circulation process for forming a circulation flow of activated sludge, And a raw water addition step of adding raw water into the circulation flow of the activated sludge.
The activated sludge circulation flow circulates from the anaerobic microorganism treatment tank through the aerobic microorganism treatment tank, the treated water is separated at the sludge sedimentation section, and the sludge is concentrated, and this concentrated sludge is treated with the anaerobic microorganism. It is a circulating flow sent to the tank. Moreover, the said activated sludge process process is a sludge circulation process and raw | natural water addition process processed using the above-mentioned microorganisms reaction tank.

The wastewater treatment method using the microbial reaction tank 1 has the following excellent characteristics as compared with the conventional wastewater treatment method.
In the conventional wastewater treatment method, raw water and return sludge are mixed in a certain ratio and flow into the aeration tank, and then the returned sludge in contact with the sludge and treated water are separated in the sedimentation tank, which is the next step. Until the activated sludge mixed with the first contact and the raw water are discharged, the raw water is pushed out and flows only by contacting with the same activated sludge bacteria.
The waste water treatment method using the microbial reaction tank 1 is a method in which a circulating flow of activated sludge circulating up and down is formed, and raw water is added to the circulating flow. It is an energy-saving wastewater treatment method because the sludge circulation flow is formed by using the upflow by aeration air used for microbial treatment without using a circulation pump to make the circulation flow of activated sludge. Furthermore, it is the processing method which can implement aeration of an aerobic microorganism processing tank efficiently.
The raw water may be added anywhere in the circulation flow path, but is preferably an aerobic microorganism treatment tank. More preferably, an anaerobic microorganism treatment tank is suitable. In the case of treatment using a circulating flow in the wastewater treatment method of the present invention, the treated water is at least BOD is 800 mg / L or more and the total nitrogen amount (hereinafter referred to as TN) is 40 mg / L or more. The BOD is usually very low, 20 mg / L or less, and generally the water quality of the discharged water can be operated at a BOD of 10 mg / L or less.
In addition, if raw water is added to the sludge sedimentation part in the circulation flow path formed on the outer peripheral surface of the cylindrical inner tank that is an aerobic microorganism treatment tank, the contact between the sludge and the raw water becomes insufficient, and Adsorption may be insufficient. In that case, contaminated substances in the raw water which is partially untreated may be mixed with the treated water, resulting in deterioration of the treated water. However, when the water quality regulation value is loose, raw water can be added to the sludge sedimentation part in the circulation flow path, for example, as a primary treatment facility such as sewage discharge with a BOD of 300 mg / L or less or 600 mg / L or less. There is a case.

Hereinafter, the wastewater treatment method for raw water containing high-concentration nitrogen-containing pollutant using the microbial reaction tank 1 will be described in detail with reference to FIG. FIG. 6 is a diagram showing a circulation path of the water to be treated and the activated sludge in the microorganism reaction tank 1. In FIG. 6, the hatched portion is a portion where the concentration of activated sludge is high, and the arrows indicate the circulation direction of the treated water and activated sludge.
Raw water as water to be treated containing a pollutant whose solid content has been separated by a wedge wire screen or the like is continuously supplied from a raw water supply port 10 provided at the bottom of the microorganism reaction tank 1. In addition, it is preferable to measure BOD and SS of the raw | natural water supplied beforehand. Examples of raw water include raw water containing BOD of 800 mg / L or more, chemical oxygen demand (hereinafter referred to as COD) of 300 mg / L or more, and TN of 40 mg / L or more. It is also suitable for treating raw water containing a normal hexane extract oil concentration (hereinafter referred to as n-Hex) in the range of 50 mg / L or more.

The microorganism reaction tank 1 contains activated sludge in an amount of 5,000 to 12,000 mg / L in terms of solid content, and the raw water first comes into contact with the activated sludge in an anaerobic state within the cylindrical lower part 3d, and the denitrification reaction is performed. Done. The raw water to be treated supplied from the raw water supply port 10 and the circulated activated sludge are circulated in the lower part 3d of the cylinder by the rotation of the stirring blades or the air blown from the air diffuser to undergo anaerobic microorganism treatment reaction. The
Next, the raw water and the activated sludge move through the communication hole 3b to the cylindrical upper portion 3c into which air is blown, and in contact with the activated sludge in the cylindrical upper portion 3c in an aerobic state, the rotation of the stirring blade or the air blowing port As a result of more air ejection, the nitrification reaction, which is an aerobic microorganism treatment reaction, proceeds in the cylindrical upper part 3c. As the nitrification reaction proceeds, the pH of the treated water decreases. The pH, ORP, and DO of the liquid to be treated are measured by the treated water quality measuring device 6, and the circulation amount of the raw water or the water to be treated is determined based on these values. Specifically, the amount of air blown is adjusted so that the ORP can be maintained at +10 mV or more in the aerobic reaction processing section where the nitrification reaction is performed and −10 mV or less in the anaerobic reaction processing section where the denitrification reaction is performed. Circulate treated water. The circulation amount can be easily achieved by controlling the air amount and / or the circulation rate control device without using a circulation pump or the like. For this reason, the wastewater treatment method of the present invention is an energy-saving wastewater treatment method. In addition, since the equipment including the microbial reaction tank of the present invention can adjust each unit of the microbial reaction, it is easy to program these controls in advance and automatically operate unattended. Have.

The circulation rate is controlled by the circulation rate control device 4, and the treated water and a part of the activated sludge discharged from the upper part of the cylindrical upper part 3c flow down the frustoconical outer peripheral surface having an inclination angle of about 45 degrees. The treated water and activated sludge that have flowed out pass through the cylindrical control plate 5 disposed close to the inclined surface of the frustoconical outer peripheral surface and the sludge concentrating portion 5b formed by the inclined surface. In addition, rapid forced sedimentation of activated sludge becomes possible. Moreover, separation of the purified treated water and activated sludge is facilitated, and the separated treated water is discharged from the treated water discharge port 11 or filtered through the membrane separation device 14 to be discharged or reused. .
The activated sludge that has been rapidly forced to settle is concentrated and deposited between the inner surface of the outer tank and the outer peripheral surface of the inner tank. The accumulated activated sludge moves to the anaerobic microorganism treatment reaction section while mixing with the water to be treated and circulates in the microorganism reaction tank.
The wastewater treatment method of the present invention can easily absorb fluctuations in the load of raw water by circulating the inside of an anaerobic / aerobic tank at a circulation rate of 3 to 20 while the activated sludge is concentrated. Further, since the circulation rate is maintained within this range, the activated sludge is acclimatized and becomes an activated sludge that is optimal for wastewater treatment.

In a microbial reaction tank, when the BOD load of raw water is small but the nitrogen concentration is high, denitrifying nutrients made of organic substances such as proton donors, such as methanol, are added to the anaerobic reaction treatment section. In this case, since the pH of the treated water is likely to increase, it is preferable to add a mineral acid such as hydrochloric acid.

The wastewater treatment method using the microbial reaction tank of the present invention may use one microbial reaction tank or a plurality of microbial reaction tanks. In this case, the discharged water from the first tank is introduced into the raw water supply port of the second tank. For example, when two microbial reaction tanks are connected in series, the ratio of the volume of the nitrification reaction part and the volume of the denitrification reaction part in the second tank can be changed more effectively by changing the ratio in the first tank. Waste water treatment can be performed. Specifically, denitrification and dephosphorization can be performed by making the volume ratio smaller than that of the first tank.

Moreover, the wastewater treatment method using the microorganism reaction tank of the present invention can be performed in combination with a conventional wastewater treatment method. For example, in a wastewater treatment facility consisting of an existing aerobic nitrification tank and an anaerobic denitrification tank, by supplying the effluent from each tank to the microbial reaction tank of the present invention, more effectively digesting pollutants and Denitrification and dephosphorization can be performed.

FIG. 7 shows a block diagram of the circulating wastewater treatment method of the present invention.
The wastewater discharged from the sewage discharge source 15 circulates through the microbial reaction tank 1, thereby providing a wastewater treatment method that leads to saving of water resources. Further, the sludge generated in the microorganism reaction tank 1 is digested in the process of circulating between the raw water aeration control tank 16 and the surplus sludge amount is not substantially discharged. Hereinafter, each process is demonstrated in order.

Step 1:
Step 1 is a step of supplying wastewater discharged from the sewage discharge source 15 to the raw water aeration adjusting tank 16. Examples of the sewage discharge source 15 include accommodation facilities such as hotels. The waste water discharged from the sewage discharge source 15 includes water for daily use mainly used in toilets, hand washing, baths and the like, and is stored in the waste water storage tank 15b.

Step 2:
In step 2, the wastewater discharged from the sewage discharge source 15 and the sludge supplied in step 4 are mixed and adjusted in the raw water aeration adjustment tank 16 so that the ORP of the wastewater becomes a positive value. This is a step of supplying the treated raw water to the microbial reaction tank 1. By adjusting the aeration so as to have a positive value, activated sludge treatment can be performed in which hydrogen sulfide, ammonia, mercaptan, etc., which cause bad odor, are oxidized and odor is hardly emitted.
The aeration process in the raw water aeration control tank 16 is performed by an aeration process in which the residence time of the wastewater is 3 hours or more, preferably 5 hours or more. Aeration treatment is performed in the presence of sludge, and wastewater containing sludge is supplied to the microorganism reaction tank as treated raw water.

Step 3:
Step 3 is an activated sludge treatment step in which anaerobic and aerobic microorganism treatment is continuously performed in the microorganism reaction tank 1. The treated raw water is subjected to aeration treatment in the raw water aeration adjusting tank 16, and the pH is naturally adjusted by the pH buffering action of the microorganisms. Can be used effectively.
In the present invention, the anaerobic microbial treatment in the microbial reactor 1 refers to a treatment in a state where DO is less than 0.05 mg / L, and the aerobic microbial treatment refers to DO of 0.05 mg / L or more, preferably 0.1 mg. / L or more, more preferably treatment in a state of 0.2 mg / L or more. Furthermore, it means an operation in which the ORP is less than −80 mV in the anaerobic microorganism treatment and the ORP is −80 mV or more in the aerobic microorganism treatment, preferably in a positive state.
The microbial reaction tank 1 anaerobically and aerobically digests the sludge contained in the treated raw water, and decomposes most of the pollutants adsorbed by the sludge into gases such as carbon dioxide, water, nitrogen gas, and methane gas. In addition, since sludge is used for the growth of microorganisms and most of it becomes digested sludge that has been transformed into cells, the amount of sludge is significantly reduced.

Step 4:
Step 4 is a step of supplying sludge generated by the microorganism reaction tank 1 to the raw water aeration control tank 16.
The raw water aeration tank 16 can be obtained by adding air blowing equipment to an existing raw water tank when renovating the existing wastewater treatment equipment.
A large solid content in the wastewater to be treated is removed with a screen or the like and stored in the raw water aeration control tank as the raw water to be treated. The raw water aeration tank 16 is supplied with the sludge generated in the microbial reaction tank 1 and stirred and mixed with the wastewater discharged from the wastewater discharge source 15 to destroy the refractory substances and activated sludge in the wastewater. For example, a pollutant that tends to cause abnormal treatment of activated sludge is contacted and adsorbed on the sludge. Since this sludge is the sludge treated in the microbial reaction tank 1, it is an activated sludge fungus suitable for the wastewater to be treated. For this reason, by supplying the sludge to the wastewater, the activity of the activated sludge is maintained at a high level, so that the occurrence of abnormal phenomena during the activated sludge treatment in the microorganism reaction tank is reduced, and the treatment can be stabilized. In addition, when there exists sludge which is difficult to process, it is extracted as excess sludge.

The sludge supplied to the raw water aeration adjustment tank 16 is supplied in a range where the sludge concentration in the raw water aeration adjustment tank 16 is 500 to 8000 mg / L as MLSS. Preferably, it is supplied in a range of 1000 to 5000 mg / L. When the MLSS is less than 500 mg / L, the sludge cannot adsorb the pollutant that adversely affects the activated sludge, so that the activated sludge treatment becomes unstable. Moreover, when MLSS exceeds 8000 mg / L, the sludge will adsorb most of the pollutants, and the biochemical oxygen demand (hereinafter referred to as BOD) contained in the treated raw water will decrease.

Step 5:
Step 5 is a step of returning the treated water introduced into the membrane separation device 14 by the microorganism reaction tank 1 and separated from the membrane separation device 14 to the sewage discharge source 15. The treated water filtered by the membrane separator 14 is stored in a treated water storage tank 15a provided in a sewage discharge source 15 of a hotel or the like, used in each room of a hotel as domestic water, and then stored in a drainage storage tank 15b. It is done. Moreover, it can discharge as some discharge water. Since water for domestic use can be reused in this way, effective use of water resources can be achieved.

Since the microorganism reaction tank of the present invention can continuously perform anaerobic and aerobic microorganism treatment of raw water in a simple shape even when the capacity of the reaction tank is large without substantially discharging the amount of excess sludge, It can be used as a wastewater treatment facility containing high-concentration pollutants. In addition, a membrane separation device that can filter the treated water is provided, and the treated water can be used as water for daily life for hotels that effectively use water resources.

DESCRIPTION OF SYMBOLS 1 Microbial reaction tank 2 Outer tank 3 Cylindrical inner tank 4 Circulation rate control apparatus 5 Cylindrical control board 6 Water quality measuring apparatus 7 Rotating shaft 8 Air inlet 9 Support pillar 10 Raw water supply port 11 Treated water discharge port 12 Settling fixation Prevention device 13 Sludge outlet 14 Membrane separation device 15 Sewage discharge source 16 Raw water aeration control tank

Claims

An outer tub, a cylindrical inner tub disposed inside the outer tub and having upper and lower openings, and a circulation rate control device for controlling the circulatory rate of water to be treated provided on the upper portion of the cylindrical inner tub And a cylindrical control plate for allowing sludge to settle by the lower surface being opened close to the inclined surface of the upper outer periphery of the cylindrical inner tank, and the outer and inner sides of the cylindrical inner tank A treated water quality measuring device provided in a raw water supply port provided in a circulation path of treated water circulating in the outer tank and the inner tank and a treated water discharge port provided in an upper portion of the outer tank. A microbial reaction tank comprising:
The cylindrical inner tank is divided into a cylindrical upper part and a cylindrical lower part with a partition wall having a communication hole in the center part,
The cylindrical upper portion has a frustoconical apex having an open top and bottom surface, and an inclination angle of a height direction cross-section passing through the center of the frustoconical shape is 40 degrees to 60 degrees. The partition wall provided in the cylindrical inner tub by a plurality of support pillars provided with a plurality of air blowing holes around the communication hole and the peripheral edge of the partition wall, and fixed to a base serving as a bottom surface of the outer tub Is an aerobic microorganism treatment tank arranged inside the outer tank,
The cylindrical lower part is an anaerobic microorganism treatment tank having an opening on the bottom surface,
The raw water supply port is a plurality of discharge ports or slits provided in an annular raw water supply unit disposed at the lower part of the opening of the anaerobic microorganism treatment tank,
At least one settling and fixing preventing device selected from a scraper and a stirring flow generating device for preventing settling and fixing of the settled sludge is provided at the lower part of the outer tank in which the sludge is settling,
Means for detecting at least one measurement value selected from the hydrogen ion concentration, redox potential and dissolved oxygen amount of the water to be treated measured by the water quality measuring device, and the measurement value detected by the means; Means for controlling the circulation rate in the tank to be treated to 3 to 20 is provided in the circulation rate control device, and this circulation rate control device opens and closes the liquid level control valve, rotates the liquid level control control plate or It is a device that controls at least one amount selected from vertical movement and the amount of air blown from the air blowing port,
A membrane separation device provided inside or outside the microorganism reaction tank and capable of filtering treated water;
The raw water supplied from the raw water supply port circulates in the tank together with the activated sludge through the inside of the cylindrical inner tank, the outer peripheral surface of the cylindrical inner tank, and the activated sludge settled in the lower part of the outer tank. Thus, a microorganism reaction tank characterized in that anaerobic microorganism treatment and aerobic microorganism treatment are continuously performed.
2. The microbial reaction tank according to claim 1, wherein the lower part of the cylinder has a volume 1/10 to 1 times the volume of the upper part of the cylinder.
The microbial reaction tank according to claim 1, wherein the cylindrical lower part has an inverted truncated cone shape having an opening having a larger area than the opening of the upper part of the cylinder.
The microbial reaction tank according to claim 1, wherein the membrane separation device is an immersion type membrane separation device.
A circulating wastewater treatment method including an activated sludge treatment step using the microorganism reaction tank according to claim 1,
Step 1 of supplying wastewater discharged from the sewage discharge source to the raw water aeration control tank,
In this raw water aeration adjusting tank, after adjusting the aeration so that the oxidation-reduction potential becomes a positive value, step 2 of supplying the adjusted treated raw water to the microorganism reaction tank;
An activated sludge treatment step 3 in which anaerobic and aerobic microorganism treatment is continuously performed in the microorganism reaction tank;
Supplying sludge generated from the microbial reaction tank to the raw water aeration control tank;
And a step 5 of returning the treated water introduced into the membrane separation apparatus and separated by the apparatus to the wastewater discharge source.