JPH09308892A - Biological purification of waste water and waste water treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste water purifying method and a waste water treatment apparatus not almost generating the abrasion of a floatable carrier in an aerobic decomposition tank and facilitating the culture of bacteria on the carrier and having large aerobic decomposition capacity. SOLUTION: An aerobic decomposition tank 1 is laterally partitioned into two tanks by a partition wall 2 and a reticulated material 3 preventing the passage of a carrier is horizontally provided to the respective tanks in a single stage or a multistage fashion to demarcate the respective tanks into a plurality of chambers in an up and down direction. The respective chambers are loosely packed with the floatable carrier. Air diffusing and distributing device 5 are provided to the bottom parts of the respective tanks. An opening part 13 is provided to the lower part of the partition wall 2 of the tank communicating with the sedimentation tank 16 of the partitioned aerobic decomposition tank 1 and the front tank adjacent thereto. The transfer pipe 9 returning a part of water to be treated to the front tank by a circulating pump 6 is provided to the tank communicating with the sedimentation tank 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wastewater biological purification method and wastewater treatment apparatus for purifying wastewater containing garbage such as cooking waste of various food materials, wastewater containing oil and the like.

[0002]

2. Description of the Related Art Conventionally, in order to purify waste water, a buoyant carrier is immersed in an aerobic decomposition tank, microorganisms are allowed to adhere to the tank, and the buoyant carrier is circulated together with the water to be treated in the tank and aerobically decomposed. It uses a fluidized bed that sends air from the bottom of the tank to decompose organic substances.

[0003]

When purifying wastewater in a conventional fluidized bed, a large amount of power is required to circulate the flotation carrier together with the water to be treated, and the flotation carrier is aerobically decomposed during circulation. There was a problem in that it was rubbed against the concrete tank wall of the tank and abraded severely, resulting in poor durability. In addition, since the growth of microorganisms does not occur at the initial stage of loading the buoyant carrier, the specific gravity is light because the load is small, and it does not swirl because it floats near the surface of the water, so a culture tank for acclimatization to pre-attach the microorganisms to the buoyant carrier is provided. Needed. Further, the amount of the floatable carrier to be charged in the aerobic decomposition tank is limited to 30% of the aerobic decomposition tank volume, and if it exceeds the limit, the aerobic decomposition capacity is limited because it is not circulated.

The buoyant carrier is liable to be exfoliated by microorganisms to be cultivated due to circulation or air flow, and since the buoyant carrier uses a polyester-based flexible polyurethane foam, it is easily hydrolyzed and has no durability. It had a drawback.

From the above point of view, the present invention shows that the microorganism-immobilized carrier having the floatable carrier hardly wears, the microorganism can be easily cultured on the microorganism-immobilized carrier having the floating property, and the aerobic decomposition ability is large. The biological purification method and the wastewater treatment device of the present invention are provided.

[0006]

In order to solve the above problems, the method of the present invention is an aerobic decomposition tank comprising a plurality of steps such as a liquefaction decomposition step, an aerobic treatment step and a precipitation treatment step. Is horizontally partitioned, and a mesh-like body that blocks the passage of carriers is horizontally installed horizontally in a single or multi-stage in each partitioned tank, and each tank is divided into several chambers in the vertical direction and floated in each chamber. The carrier for immobilizing microorganisms that has the property of slowly adsorbing and filling, and communicating with the settling tank of the partitioned aerobic decomposition tank The water to be treated in the tank is passed upward through the carrier layer and adjacent to this tank. The water to be treated in the front tank passes through the carrier layer in a downward flow, and air is diffused from the bottom of each tank to purify the water to be treated and to be treated from the tank which communicates with the settling tank. By returning part of the water to the front tank and repeating the purification process, wastewater containing organic impurities can be treated biologically. It is characterized in that the purifying.

Further, in the method of the present invention, the aerobic decomposition tank is laterally partitioned into three or more tanks, and the treated water is sequentially directed downward from the foremost tank to the succeeding tank except the tank communicating with the precipitation tank. The carrier layer of each chamber is passed by a flow, and the tank communicating with the precipitation tank is passed through the carrier layer of each chamber in an upward flow from below.

Further, the apparatus of the present invention is provided with a plurality of treatment tanks such as an anaerobic decomposition tank, an aerobic decomposition tank, and a precipitation tank, and the treated water is sequentially transferred to these treatment tanks to purify the wastewater. In the treatment equipment, the aerobic decomposition tank is horizontally partitioned, and each of the partitioned tanks is a single or multi-tiered horizontally-arranged mesh-like body that prevents the passage of carriers. Is divided into
Each chamber was gently filled with a microbial immobilization carrier having buoyancy, and an aeration distribution device was installed at the bottom of each tank, and a tank that communicates with the settling tank of the partitioned aerobic decomposition tank and this tank An opening is provided in the lower part of the partition wall between the front tank and the front tank, and a transfer means for returning a portion of the treated water to the front tank is provided in the tank communicating with the precipitation tank. It is characterized by that.

Further, in the apparatus of the present invention, the aerobic decomposition tank is laterally partitioned into three or more tanks, and the treated water is sequentially directed downward from the top tank to the succeeding tank except the tank communicating with the precipitation tank. A flow path that connects the bottom of the front tank to the top of the rear tank is formed in the partition walls of the front tank and the rear tank so that it can be passed through the carrier layer of each chamber by the flow. A communication part is provided below the partition wall of the tank to be connected.

Therefore, according to the method and apparatus of the present invention, since the microorganism-immobilized carrier (hereinafter referred to as carrier) is gently charged and filled in the chamber divided into upper and lower parts by the mesh-like body, it is in a floating state, and the fine particles are surrounded. Even if air bubbles adhere and float up, each chamber is defined by a net-like body that prevents passage of the carrier, so that a carrier layer is formed in each chamber.

When the microorganisms grow on the carrier, the specific gravity increases and the particles tend to sink. However, they are levitated by the air flow from the bottom of each tank due to the air diffusion, and the microorganisms grow in the settling tank of the partitioned aerobic decomposition tank. Since the water to be treated passes through the carrier layer in a downward flow from the upper side of each tank except the connecting tank, it is in a floating state above without moving, and only the water to be treated passes between the carriers.

Further, since the aerobic decomposition tank is divided into two or more tanks and each tank is divided into several chambers in the vertical direction, the water to be treated passes through the carrier layer a plurality of times and communicates with the precipitation tank. In case of two tanks, a part of the water to be treated is returned to the front tank, and in the case of three or more tanks, it is returned to the front tank and the purification treatment is repeated, whereby the water is efficiently purified.

The mesh is prevented from clogging by the downward flow of the water to be treated from above the tank and the air flow from the bottom of the tank. Since the water to be treated flows downward from all the tanks except the tank connected to the settling tank, it has the same action as each tank.
In addition, the tank communicating with the settling tank of the aerobic decomposition tank passes the water to be treated in an upward flow with respect to the floatable carrier-packed layer, but by dividing the carrier layer by several stages of meshes in the vertical direction Since air due to air diffusion in the lower part fluidizes the packed carrier, the capturing power of fine particles is reduced but the oxidative decomposition power by organisms is improved.

The carrier used in the method and apparatus of the present invention is characterized in that the carrier for immobilizing microorganisms is a flexible polyurethane foam in which the polymer chain of the polyol, which is the main raw material, is composed of ether bonds, and the pores on the inner and outer surfaces are mutually It is a dice-shaped granular material having a size of one side that communicates with each other of 10 to 30 mm.

Therefore, since the carrier of the present invention uses the flexible polyurethane foam of ether type, it is hard to be hydrolyzed and has sufficient durability. And, since the pores on the inner surface and the outer surface are in communication with each other, the microorganisms can be easily cultured because they enter not only the surface of the carrier but also the inside thereof.
Microorganisms are not separated by the water to be treated or the air flow, and the water to be treated is purified inside the carrier.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. 1 shows an embodiment of the method and apparatus of the present invention, and FIG. 2 is a sectional view when the aerobic decomposition tank is divided into two tanks, and FIG. 2 is a sectional view when the aerobic decomposition tank is divided into three tanks. FIG. 3 is a partial plan view of the above, and FIG. 4 is a partial enlarged sectional view showing the operation of the above.

1 is an aerobic decomposition tank.
Then, it is divided into two tanks by the partition wall 2. In FIG. 2, it is divided into three tanks, but it is also possible to laterally partition into three or more tanks. Inside each tank, a net 3 is horizontally installed in two parts, an upper part, a lower part and between them, and an upper chamber 1A and a central chamber 1B are provided.
And the lower chamber 1C. Although it is divided into three chambers in the drawing, it may be divided into a single-stage or multi-stage chamber.

Upper chamber 1A, central chamber 1B, and lower chamber 1C
A large number of floatable carriers 4 carrying aerobic microorganisms that aerobically decompose organic impurities contained in the water to be treated are gently filled therein. The mesh of the mesh body 3 is formed in a size that prevents the carrier 4 from passing therethrough, and the carrier 4 does not come out of the room.

The carrier 4 is a soft polyurethane foam in which the polymer chain of the polyol, which is the main raw material, is composed of ether bonds, and is a dice-shaped granular material having pores on the inner and outer surfaces communicating with each other and having a side of 10 to 30 mm. , Density 16 to 70 kg / m ³ , specific gravity 0.016 to 0.07,
Pores of 0.5 to 1.0 mm communicate with each other. The filling rate of the carrier filled in each tank is 30 to 80% of the volume of each tank.
It is an amount corresponding to the volume of.

Reference numeral 5 denotes an air diffuser provided at the bottom of each of the partitioned aerobic decomposition tanks 1. Air or pure oxygen is supplied from a pump provided outside the aerobic decomposition tank 1 through a supply pipe 6. Is supplied to each tank. 7 is a drainage supply pipe, and the drainage supply pipe 7
In the aerobic decomposition tank divided into two tanks, the wastewater treated in the anaerobic decomposition tank (not shown) in the previous process is introduced above the inside of the front tank, and the aerobic decomposition tank divided into three or more tanks. Then, it is introduced into the front tank. 8 is a settling tank 16 of the aerobic decomposition tank 1 partitioned
Is a circulation pump provided in the tank that communicates with the settling tank 16, and if a part of the water to be treated in the tank that communicates with the settling tank 16 is two tanks, to the front tank, and if there are three or more tanks, the front tank It is connected to a transfer pipe 9 for returning to the upper part inside.

In the case of three or more tanks, the water to be treated is divided into four parts by the front wall adjacent to the tank connected to the settling tank 16 and the partition wall 2 of the tank in front of this tank. The flow channel 10 is provided with a communication hole 11 in the lower portion, which communicates with the bottom of the front tank, and an upper portion with an opening 12 in the upper portion of the subsequent tank.
It is shaped like a chimney that extends vertically upward. Reference numeral 13 denotes an opening provided in the lower part of the partition wall 2 between the tank communicating with the precipitation tank 16 and the front tank adjacent to this tank,
The water to be treated in the front tank flows in through the opening 13 and becomes an upward flow. Reference numeral 14 is an exhaust pipe, 15 is an advection pipe for introducing treated water into the precipitation tank 16 from a tank connected to the settling tank 16 of the aerobic decomposition tank 1, and 17 is a treated water discharge tube of the precipitation tank 16.
Is a sludge discharge pipe provided at the bottom of the settling tank 16.

Next, a method for purifying water to be treated will be described with reference to the drawings. When the aerobic decomposition tank 1 is partitioned into two tanks, when the aerobic decomposition tank 1 is partitioned into three tanks or more above the drainage supply pipe 7 in the front of the aerobic decomposition tank 1. The water to be treated introduced into the upper part of the tank in the uppermost part passes through the four layers of the carrier in the central chamber 1B and the lower chamber 1C from the four layers of the carrier in the upper chamber 1A in the tank in the downward flow A. The carrier 4 carries aerobic microorganisms, which undergo aerobic decomposition. The carrier 4 is in a floating state due to the downward flow A of the water to be treated and the air flow B from below, and does not move.

When the water to be treated that has undergone aerobic decomposition is divided into two tanks, it flows into the tank communicating with the settling tank 16 through the opening 13 provided in the lower portion of the partition wall 2, and also three tanks. When it is divided into the above, the flow path 1 is made through the communication hole 11 at the bottom of the tank.
It is introduced through 0 through the opening 12 to the upper part of the following tank,
Again, in the downward flow A, the carrier 4 layers aerobically decomposed, adjoining the precipitation tank 16 through the opening 13 at the bottom of the partition wall 2 between the tank communicating with the precipitation tank 16 and the front tank adjacent to this tank. In the case where a part of the water to be treated in this tank is divided into two tanks by an upward flow C, the upper part of the tank is divided into two tanks. It is returned to the frontmost tank by the transfer pipe 9, repeatedly aerobically decomposed, and transferred to the precipitation tank 16 by the advection pipe 15 from the tank communicating with the precipitation tank 16.

[0023]

According to the present invention, the carrier does not move due to the downward flow of the treated water from above and the air flow from the lower side, and only the treated water passes between the carriers in the floating state. In addition, it requires less power than a carrier that circulates, and has durability without wear of the carrier due to circulation. Further, since the carrier is not circulated, it is not necessary to acclimate at the time of initial charging to the aerobic decomposition tank 1 even if there is no growth of microorganisms, and the amount of the carrier charged is 30 to 80% of the aerobic decomposition tank volume.
The amount is equivalent to the volume of, and the aerobic decomposition ability can be significantly improved. Since the water to be treated repeatedly passes through the carrier layer, it is efficiently purified. Further, since the water to be treated is introduced in a downward flow from above the tank except for the tank communicating with the settling tank, it is purified under the same conditions in all the tanks. It should be noted that the provision of the flow path when it is partitioned into three or more tanks has an advantage that it is convenient for cleaning. Also, when the water to be treated is passed in an upward flow with respect to the floatable carrier packed bed, fine particles are captured in the packed bed,
Although there was a drawback that the packed bed was clogged in about 1 to 2 days, by dividing the packed bed by several stages of meshes in the vertical direction, air due to air diffusion in the lower part fluidized the packed carrier and thus fine particles were obtained. The ability to capture oxidase is reduced, but the ability to be decomposed by living organisms is improved. In addition, since the carrier uses an ether type flexible polyurethane foam, it is hard to undergo hydrolysis and has sufficient durability, and since the pores on the inner and outer surfaces are in communication with each other, microorganisms enter the carrier. It is a useful invention because it is easily cultivated and microorganisms are not separated by the water to be treated or the air flow.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of an apparatus according to the present invention, in which an aerobic decomposition tank is divided into two tanks.

FIG. 2 is a cross-sectional view showing an embodiment of the apparatus according to the present invention, in which the aerobic decomposition tank is divided into three tanks.

FIG. 3 is a partial plan view showing an embodiment of the apparatus according to the present invention, in which the aerobic decomposition tank is divided into three tanks.

FIG. 4 is a partially enlarged sectional view showing the operation of the device according to the present invention.

[Explanation of symbols]

 1 Aerobic decomposition tank 1A Upper chamber of aerobic decomposition tank 1B Central chamber of aerobic decomposition tank 1C Lower chamber of aerobic decomposition tank 2 Partition wall 3 Reticulate body 4 Microorganism immobilization carrier 5 Aeration distribution device 6 Supply pipe 7 Drainage Supply pipe 8 Circulation pump 9 Transfer pipe 10 Flow path 11 Communication hole 12 Opening 13 Opening 14 Exhaust pipe 15 Advection pipe 16 Settling tank 17 Treated water discharge pipe 18 Sludge discharge pipe A Downflow of treated water B Air flow C Upward flow

Claims (6)

[Claims] 1. In a wastewater treatment method comprising a plurality of steps such as a liquefaction decomposition treatment step, an aerobic treatment step and a precipitation treatment step, an aerobic decomposition tank is laterally partitioned, and a carrier is passed through each partitioned tank. Horizontally installed in a single or multi-stage horizontally to prevent the, each chamber is divided into several chambers in the vertical direction, each chamber is gently charged and filled with a microbial immobilization carrier having levitation properties, The treated water in the tank connected to the settling tank of the partitioned aerobic decomposition tank passes through the carrier layer in an upward flow, and the treated water in the front tank adjacent to this tank flows in a downward flow. While passing through the carrier layer, air is diffused from the bottom of each tank to purify the water to be treated, and a portion of the water to be treated is returned from the tank that connects to the settling tank to the front tank for purification treatment. A biological purification method for wastewater, characterized in that the wastewater containing organic impurities is biologically purified by repeating. 2. The aerobic decomposition tank is laterally partitioned into three or more tanks, except for the tank communicating with the settling tank, from the frontmost tank to the succeeding tank, the treated water is sequentially flowed downward from above. 2. The method for biologically purifying wastewater according to claim 1, wherein the carrier layer is passed through, and the tank communicating with the precipitation tank is passed through the carrier layer in each chamber in an upward flow from below. 3. The microorganism-immobilized carrier is a flexible polyurethane foam in which a polymer chain of a polyol, which is a main raw material, has an ether bond, and has a size of 10 to 30 mm on one side in which pores on the inner surface and the outer surface communicate with each other. The method for biologically purifying wastewater according to claim 1 or 2, which is a granular substance of. 4. A wastewater treatment apparatus for cleaning wastewater by providing a plurality of treatment tanks such as an anaerobic decomposition tank, an aerobic decomposition tank, and a precipitation tank, and sequentially advancing the water to be treated to these treatment tanks to purify the wastewater. The aerobic decomposition tank is horizontally partitioned, and each of the partitioned tanks is vertically divided into several chambers by a mesh-like body that prevents the passage of carriers horizontally laid in a single stage or multiple stages. The microorganism-immobilized carrier having buoyancy is gently filled into the room, and
An air diffuser is installed at the bottom of each tank, and an opening is provided at the bottom of the partition wall between the tank that communicates with the settling tank of the aerobic decomposition tank that is partitioned and the front tank that is adjacent to this tank. With
A wastewater treatment device, characterized in that a transfer means for returning part of the water to be treated to the front tank is provided in a tank communicating with the settling tank. 5. The aerobic decomposition tank is laterally partitioned into three or more tanks, and the treated water is sequentially flowed downward from the frontmost tank to the subsequent tank except the tank communicating with the precipitation tank. A flow path that connects the bottom of the front tank to the top of the rear tank is formed in the partition walls of the front and rear tanks so that it can pass through the carrier layer. The wastewater treatment equipment according to claim 4, wherein a communication portion is provided at a lower portion of the wall. 6. The microorganism-immobilized carrier is a flexible polyurethane foam in which a polymer chain of a polyol, which is a main raw material, has an ether bond, and a dice shape in which pores on an inner surface and an outer surface communicate with each other and a side of which is 10 to 30 mm. The wastewater treatment device according to claim 4 or 5, which is a granular material.