JPH01123697A - Aerobic biological treatment device for organic waste water - Google Patents

Abstract

PURPOSE:To obtain treated water having high clarity and to facilitate the sepn. of microorganisms from the treated water in the upper part of a biological reaction vessel by providing a raw water inflow part to the lower part of the biological reaction vessel and a treated water outflow part to the upper part thereof, increasing the sectional area of the upper part thereof and disposing a granular mixed microorganism discharge port to the lower part having a small sectional area. CONSTITUTION:Living waste water (raw water) and part of the treated water are admitted by a raw water pump 4 and a circulation pump 5 into an oxygen dissolution tank 1. On the other hand, the gaseous oxygen produced by an oxygen generator 3 is supplied to the tank 1 where the required quantity of the oxygen is dissolved into the raw water and treated water sprayed from sprays 17, 17'. The liquid mixture composed of the raw water and treated water dissolved therein with the oxygen is passed in upward current in the biological reaction vessel 2 from the lower part thereof where the granular mixed microorganisms 15 and the raw water are brought into contact with each other to aerobically clean the raw water. The granular mixed microorganisms 15 are then separated from the treated water in the upper part (tapered part 16) of the large sectional area of the vessel 2 and the treated water is discharged through an outflow line 13. On the other hand, the excess granular mixed microorganisms 13 are discharged from a discharge port 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an apparatus for biologically treating organic wastewater such as sewage, industrial wastewater, and human waste under aerobic conditions.

[Conventional technology and its problems]

The activated sludge method, which is a typical aerobic feed processing method, aerates a mixed liquid consisting of wastewater and activated sludge in an aeration tank, then separates solid and liquid in a sedimentation tank, and uses the supernatant water from which the activated sludge is sedimented and separated as treated water. This is the way to get it.

The morphology of microorganisms in the activated sludge method is amorphous and sparsely packed, so it has the disadvantage of requiring a settling basin with a vast area for solid-liquid separation. During precipitation, the floc adsorbs and removes fine 88 particles in the water, resulting in a high degree of clarity in the treated water.

Edited by Yoshiaki Uehara, “New Sewage Treatment Technology – Upflow Oxygen Activated Sludge Method” (Published by Industrial River Water Research Association).

The upflow oxygen activated sludge method and its equipment aim to downsize the equipment by integrating a biological reaction tank and a settling tank and using R11 gas as an oxygen source. However, since the mixed liquid consisting of activated sludge and wastewater is directly aerated with oxygen gas, the form of the activated sludge is the same floc as the activated sludge method described above, and the area required for solid-liquid separation is smaller than that of conventional activated sludge. It is equivalent to the law.

On the other hand, in the biofilm method, microorganisms exist as a biofilm on an attached carrier, so a vast settling tank is not required for solid-liquid separation, but since the amount of activated sludge in the form of medium flocs is small, activated sludge The clarity of the legally treated water is not high.
(H) There are problems such as the high price of the adhesion carrier, leading to an increase in equipment costs.

[Purpose of the invention]

The purpose of the present invention is to form a granular mixed microbial bed with excellent sedimentation properties and clarification of treated water without using any adhering carrier by effectively utilizing the self-cohesive power of microorganisms. The object of the present invention is to provide an aerobic biological treatment device that effectively utilizes this.

[Structure of the invention]

A feature of the present invention is that by supplying cR elements without directly aerating the liquid containing microorganisms, a granular microorganism bed with excellent sedimentation properties is formed by effectively utilizing the self-cohesive power of microorganisms. The solid-liquid separation is dramatically easier than in the conventional activated sludge method, and by bringing organic wastewater into contact with the sludge bed consisting of flocculated granular mixed microorganisms in an upward flow, the biofilm is removed. This method makes it possible to obtain treated water with a high level of clarity compared to the conventional method, and the cross-sectional area of the upper part of the biological reaction tank is fully expanded, making it easier to separate particulate mixed microorganisms from the treated water and discharging them outside the biological reaction tank. 11 surplus particulate mixed microorganisms that should be
The biological reaction tank itself has a function that reduces the load on the shrinkage sludge treatment process, and by installing an agitator inside the biological reaction tank and gently stirring the sludge bed, it is possible to reduce the amount of granules. This is because it enables smooth contact between organic wastewater and particulate mixed microorganisms while promoting the formation of dead zones in the sludge bed and preventing the formation of dead zones within the sludge bed.

A granular mixed microbial bed can be produced by placing a required amount of activated sludge in a biological reaction tank and passing organic wastewater in which oxygen has been dissolved upward through the activated sludge.

In addition, in order to prevent sludge from flowing out, the rising flow rate of the liquid may be set low at first, and the flow rate may be increased as the sludge becomes granular.

In addition, if the mixture is stirred slowly at this time, granules are likely to be formed.

Usually, complete granulation is achieved within two weeks, and 1 =
8 m of dodecyl granules are obtained.

In other words, in the present invention, the required amount of mature trees is dissolved in advance in organic wastewater that does not contain activated sludge using an oxygen absorption device, and then the water is passed upward through a bed of mixed microorganisms that has become granular due to self-cohesive force. In an apparatus for aerobically biologically treating organic wastewater without breaking the clumps, the biological reaction tank has a raw water inlet at the bottom and a treated water outflow S at the top, and the area of the upper part of the biological reaction tank is large, This is an aerobic biological treatment device for organic wastewater, which is characterized by having a granular mixed microorganism outlet at the bottom with a small cross-sectional area.

In the present invention, a stirring device is used to gently stir the granular mixed microbial bed in order to promote the formation of granular materials and to prevent the formation of sludge blocks due to adhesion of granular materials to each other, and the formation of dead zones caused by this. It is preferable to provide one.

In addition, when using the device of the present invention, the flow rate above and below the liquid is 80
If m7 days or less, the flow of the granular mixed microorganism bed becomes inactive and the contact efficiency with the slurry wastewater decreases, so the liquid rising flow rate f8
It is necessary to maintain the temperature at 0m for at least 1 day.

Also, if the rising flow rate of the liquid is too high, the granular mixed microorganism bed will be empty!
i! Due to the formation of a large fluidized bed, the sludge concentration in the microbial bed decreases, resulting in a decrease in treatment efficiency. Therefore, the rising flow rate of the liquid is preferably 80 to 250 m7 days;
t, < is 100-2+am7 days.

Further, in the present invention, oxygen dissolution is performed under pressurized conditions, which is advantageous for aerobic treatment since the dissolved oxygen concentration can be increased. However, if the pressure is increased to 97 cm or more, the supersaturated gas will become bubbles in a biological reaction tank at a practical depth, which is equivalent to aerating a granular mixed microbial bed, and the formation of granules will be inhibited. The pressurization is preferably carried out at 3 kg1α2 or less.

In addition, it is preferable to use oxygen-enriched gas or pure oxygen in order to maintain #4 oxygen concentration at a high level. Also, depending on the degree of #4 organic wastewater, treatment may be necessary to eliminate the lack of oxygen supply. After circulating the water and dissolving oxygen, the water is sent to the biological reaction tank.

In the present invention, if the number of particulate mixed microorganisms in the biological reaction tank increases, the particulate mixed microorganisms may be discharged from the glJ outlet.

EXAMPLE The device of the present invention and an example of its use will be explained based on Figure 1. The dimensions of the device in which the present invention was implemented for domestic wastewater in an OE housing complex are as follows. Lower than part s 300■ Taper part part edge 500m Height Fitting height 4500 days Water depth 440 Low taper part Position 3000m from tank bottom Taper angle of inclination 60° Stirrer Rotation speed 1 to 5 rpm (variable type) Stirring rod Oxygen dissolution tank with round rods installed at 200 m intervals in the direction of the name: Inner diameter 30〇- Height 70〇- Spray nozzle Hole diameter 3- (raw water/circulated water is sprayed onto the top plate) Pressure Gauge pressure α5~2Y / Inverted 2 oxygen generator PSA type oxygen generator (effective oxygen concentration 91%V/V
) A raw water pump 4 and a raw water supply line IO' are connected to E housing complex domestic wastewater from which impurities have been removed using a fine screen.
! : Then, it is made to flow into the oxygen dissolution tank 1.

In addition, a part of the treated water is transferred to the gold circulation pump 5 through the circulation line 12.
The oxygen gas produced by the oxygen generator 3 is supplied to the oxygen dissolving tank 1 via the oxygen supply line 14. The raw water and circulating water are supplied to the oxygen dissolving tank 1 through the Spray onto the top plate through the spray nozzle 17.
In the process, oxygen is dissolved in the raw water and circulating water.

A pressure regulator 8 is attached to the top plate of oxygen #disassembly tank 1.
1. The pressure of the cable dissolving tank 1 can be set to any value from 15 to 2 Yu.

In addition, this l! I! The dissolved mineral density that can be supplied by the elementary dissolution method is 30 to 701119/l, so if only the raw water is dissolved in oxygen, there will be insufficient oxygen for aerobic treatment.Therefore, the treated water must be circulated. 71c to resolve the lack of reformation.

A mixture of raw water and treated water in which oxygen has been dissolved is sent to the water supply line 11.
Water is passed through the biological reaction tank 2 from the lower part thereof in an upward flow.

A stirrer 6 is installed inside the biological reaction tank 2,
Due to the interaction between the upward flow of the inflow water and the gentle circulation flow of the agitator 6, the particulate mixed microorganisms 15 come into contact with the wastewater while flowing, and completely purify the wastewater aerobically.

The granular mixed microorganisms 15 are solid-liquid separated by a tapered portion 16,
The supernatant water flows out as treated water from the upper part of the biological reaction tank 2 through the treated water outflow line 13.

A part of the treated water is returned to the oxygen dissolving tank 1 via the circulation pump 5 and the circulation line 12.

Excess granular mixed microorganisms 15 are removed from the granular mixed microorganism outlet 97
&: It is then discharged.

Operation results are shown in IR Table-1.

Table-1 Typical operation results As shown in Table-1, the degree of pressurization of the oxygen dissolution tank was changed.
Good quality treated water was obtained in both Eiken areas.

The particle size of the granular mixed microorganisms is 1 to 54 in the first section and 3 in the second section.
It was ~8■, and the one with higher pressure was a big failure.

The discharge level of surplus particulate mixed microorganisms was 9 in the first ward.
000~13000~9/L-12000 in the 2nd ward
At ~20,000 m9/l, a concentration effect was observed in a part of the taper.

Although the granular mixed microorganisms discharged have already collapsed due to the shear force when flowing through the discharge W, the thickening properties are slightly better than the surplus sludge of the normal activated sludge method, and the granular mixture can be left standing for 24 hours. The concentration achieved later was only 55-4%.

As mentioned above, is the flocculation power of F microorganisms applied to the present invention? It is possible to provide an aerobic treatment device for injected wastewater that can be used effectively, is more compact, and has higher performance than conventional methods. It is believed that this technology will be effectively utilized in wastewater treatment in the future.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an aerobic biological treatment apparatus 1 of the present invention.

Claims (1)

[Claims] 1. After dissolving the necessary amount of oxygen in organic wastewater in advance using an oxygen dissolving device, water is passed upward through a mixed microbial bed that has become granular due to self-cohesive force to break up microbial clumps. In a device for biologically treating organic wastewater aerobically, the biological reaction tank has a raw water inflow part at the bottom and a treated water outflow part at the top, and the cross-sectional area of the upper part of the biological reaction tank is large. An aerobic biological treatment device for organic wastewater, characterized in that a granular mixed microorganism outlet is provided in a small lower part. 2. The device according to claim 1, wherein a stirrer is provided in the biological reaction tank. 3. The device according to claim 1 or 2, wherein the rising flow rate of the liquid at the bottom of the biological reaction tank is controlled to 80 to 250 m/day. 4. The device according to claim 1, 2, or 3, wherein the oxygen dissolving device is pressurized to a gauge pressure of 3 kg/cm^2 or less. 5. The apparatus according to any one of claims 1 to 4, which uses oxygen-enriched gas or pure oxygen.