JPS6283097A - Anaerobic treatment of waste water - Google Patents

Abstract

PURPOSE:To enhance decomposition efficiency, by dividing the waste water in tank into a particle suspending region and a particle non-suspending region and withdrawing treated water from the non-suspending region. CONSTITUTION:Org. waste water is supplied to a treatment tank 1 through an inflow pipe 8 and a stirrer 3 is driven to stir waste water. By this method, bacteria supported particles 6... are suspended in the region below a flow barrier body 5 and anaerobic treatment is performed by bacteria of the particles 6.... In the region above the flow barrier body 5, a water stream is almost lost by the presence of the flow barrier body 5 and bacteria supported particles 6... are not almost present in the waste water of said region. Therefore, treated water is withdrawn from a flooding weir 7 in such a state that the particles 6... were almost separated. The suspended sludge in the region directly below the flow barrier body 5 is appropriately withdrawn from a withdrawing pipe 9 as excessive sludge.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an anaerobic treatment method for right reformed wastewater.

[Prior art and its problems]

Conventional anaerobic treatment such as denitrification of organic wastewater includes methods using suspended sludge, methods using sludge fixed on compacts,
A method of suspending microorganism-carrying particles is used.

However, the floating sludge method and the fixed sludge method have problems in that the decomposition efficiency per volume of the carapace is low, a long residence time is required, and the equipment becomes large. In addition, although the method using microorganism-supported particles has a higher decomposition efficiency, it requires a large amount of mechanical energy to suspend the particles.Furthermore, like the suspended sludge method, a settling tank is required, and the particles decomposed in the settling Pl tank are There were problems such as the need to send the water back to the treatment tank.

[Means for solving problems]

Therefore, in this invention, when carrying out anaerobic treatment by suspending particles carrying microorganisms, the wastewater in the tank is divided into a particle suspension area and a non-suspension area, and the treated water is separated from the non-suspension area. The above problem was solved by draining the liquid.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a first example of a processing apparatus used in the processing method of the present invention, and reference numeral 1 in the figure is a processing tank. The treatment tank 1 is provided with a lid 2 at its upper opening to prevent outside air from entering in order to perform anaerobic treatment, and its bottom is shaped like a pot. A stirrer 3 is provided in the treatment tank 1 to stir the organic wastewater in the treatment tank 1, and is rotated by an electric motor 4. Further, a fluid-limiting fluid 5 is provided above the middle of the processing tank 1 . fluid limited 5
is for substantially vertically dividing the wastewater in the tank 1, and has a structure that allows water permeability and prevents the propagation of water flow. Thickness of 50 to 200 sheets, honeycomb bodies, punching boats, foams with continuous open pores, etc.
A plate-shaped body processed to about 1111 is used. In addition, in the wastewater below the limited fluid 5, there are countless microorganism-carrying particles 6...
is suspended. The microorganism-carrying particles 6 can support anaerobic microorganisms such as denitrifying bacteria on diatomaceous earth, activated carbon, berculite, etc.
It is attached to, retained or included in the surface or pores of fine particles such as antifossils, plastic particles, polymer particles, etc., and its apparent specific gravity is 1°O to 1.8, preferably in the state of use. A material having a specific gravity in the range of 1.05 to 1.3 is used.

An overflow weir 7 is provided at the top of the treatment tank 1 for draining treated water that has undergone anaerobic treatment. Further, an inflow pipe 8 for supplying WNl is provided, and an outflow port at the tip thereof opens near the bottom of the tank 1.

Furthermore, an excess sludge drawing pipe 9 is provided below the fluid-limiting fluid 5 .

Next, a method for treating wastewater using this treatment device will be explained.

Organic wastewater is supplied to the treatment tank 1 through the inflow pipe 8 and stirred? jI3 is driven to stir the wastewater. As a result, the microorganism-carrying particles 6 are suspended in the fr4 region below the fluid-limited fluid 5, and anaerobic treatment is performed by the microorganisms in the particles 6. At this time, the microbial concentration in this area is 8000~
It is operated at an extremely high concentration of about 30,000 ppm.

This is due to the adoption of the microorganism-carrying particles 6.

On the other hand, in the region above the fluid-limiting fluid 5, there is almost no water flow due to the presence of the fluid-limiting fluid 5, and there are almost no microorganism-carrying particles 6 in the wastewater in this region. Therefore, the treated water is discharged from the overflow weir 7 with most of the particles 6 separated. In addition, in the area immediately below the fluid-limiting fluid 5, microorganisms may peel off from particles and fall off, resulting in floating sludge, and this floating sludge is appropriately pulled out from the surplus sludge extraction vibrator 9 as surplus sludge.

In addition, the microorganisms are thickened on the surface of the particles 6, and the particles 6, which have an apparent stopper close to 1, tend to be distributed upwards. , the particles are returned to the treatment tank 1 again.

According to such a treatment method, the treated water is drawn out through the overflow weir 7 from an area above the fluid-limiting fluid 5 where microorganism-carrying particles 6 are not substantially present, so the treated water contains particles 6.
. . . are hardly included, and a settling tank for separating the particles 6 . Moreover, since the microorganism-supporting particles 6 are used, the concentration of microorganisms in the tank can be increased to 8,000 to 30,000 ppm, and therefore the reaction time can be significantly shortened.

For example, in denitrification treatment, nitrate nitrogen 301rtg/J
The time it takes to reduce the amount of sludge to less than 1 sludge can be reduced to 1715 or less compared to the conventional suspended sludge method. For example, when alcohol waste liquid (BOD1100011+g/J) is subjected to methane fermentation treatment, a volume load of 5 to 1 (1 gBOD/m/day) can be taken.Furthermore, in the region below the fluid-limiting fluid 5, the waste water is sufficiently stirred. The process is carried out to ensure sufficient contact between wastewater and microorganisms, and the active surface of particles 6 also increases.
Combined with high microbial concentration, high removal volumetric efficiency is achieved,
The required volume of the processing tank 1 can be reduced. Further, since the number of insects in the microorganism-carrying particles 6 is 1 to 1.8, it is easy to suspend the particles 6, and less stirring energy is required.

FIG. 2 shows a second example of the apparatus used in the processing method of the present invention, and the same components as those shown in FIG. 1 are given the same reference numerals and their explanations will be omitted. In this treatment device, a sludge concentration meter or sludge interface meter 10 is provided at a position 0.7 to 0.8 below the water depth of the tank 1. This sludge concentration meter or sludge interface meter 10 measures the concentration of microorganism-carrying particles 6 in wastewater or the interface of particles 6. Sludge concentration meter or sludge interface meter 1
The signal from 0 is input to the controller 11, the signal from the controller 11 is input to the controller 11, and the drive speed of the stirrer 3 is controlled by PID control etc. with the control signal from the controller 11.
The concentration of particles 6 in the upper region of tank 1 is controlled to be below a set value. Further, a weak fluid 12 is attached to the tip of the inflow pipe 8 to moderate the flow of inflow wastewater and prevent the particles 6 from moving upward.

To anaerobically treat wastewater with such a device, the wastewater is gently flowed into the bottom of the treatment W11 through the inflow pipe 8 and the weak fluid 12, and the agitator 3 is connected to the sludge concentration meter or sludge interface meter 10. It is driven based on a signal and performs agitation to such an extent that the microorganism-carrying particles 6 do not flow upwards of the wastewater. As a result, in the lower region of the wastewater, the wastewater comes into contact with microorganisms as in the previous example, and highly anaerobic treatment is performed, and from the upper region, treated water that does not contain particles 6 is passed through the overflow weir. 7 is pulled out to the outside.

Through such processing, the same effects as in the previous example can be obtained.

FIG. 3 shows a third example of a processing apparatus for carrying out the processing method of the present invention. This is processing tank 1
A gas injector 13 is provided at the bottom, and the anoxic gas at the top of the tank 1 is injected from the gas injector 13 by a blower 14.
It stirs wastewater. Further, a funnel-shaped gas guide body 15 is provided in the center of #W1 to prevent bubbles generated from the gas injection 7jt13 from flowing into the upper region of the waste water, and to prevent the microorganism-carrying particles 6... It is designed to prevent the influx of Furthermore, a cylindrical layer 16 is disposed above the waste water surface, and an overflow 11!7 is provided inside this cylindrical layer 16, from which the treated water is drawn out.

In wastewater treatment using such a treatment device, wastewater is introduced through the inflow pipe 8, the blower 14 is operated, the anoxic gas in the tank 1 is ejected from the gas injector 13, and the wastewater is stirred. At this time, control the gas jet and adjust the bubble generation foot.
Naturally, it is necessary to prevent the microorganism-carrying particles 6 from flowing into the upper region.

The flow of the bubbles caused by the gas ejection is restricted by the gas guide body 15, so that they hardly flow into the upper region of the waste water, and therefore the microorganism-carrying particles 6 hardly flow into the upper region. Even if the particles 6... flow into this area, the gas guide body 15 will prevent the particles 6 from flowing into the cylindrical layer 1.
It flows to the outside of 6, and flows to the inside, so the overflow weir 7
Particle 6... is almost never included in the treated water. With this process as well, the same effects as in the previous example can be obtained.

4 and 5 show a modification of the processing apparatus shown in FIG. 3. FIG. The processing apparatus shown in FIG. 4 is provided with a hole 17 in the center of the gas guide body 15 through which the microorganism-carrying particles 6 fall, and two small perforated sub-holes are provided below the gas guide body 15. A guide body 18.18 is provided. In this case, particles 6 mixed into the stationary area
... falls downward from the central hole of the guide body 15, 18, 18, and the gas does not blow up into the stationary area.

In the processing apparatus shown in FIG. 5, a hole 17 made by the company is formed in the center of a gas guide body 15, and a blocker 19 with a diamond-shaped cross section is provided below this hole 17 to prevent gas from blowing up. There is. These devices have the advantage that the particles 6 do not accumulate on the upper surface of the gas guide body 15.

〔Effect of the invention〕

As explained above, the method for anaerobic treatment of wastewater of the present invention divides the wastewater in the tank vertically into the upper part when performing anaerobic treatment by suspending particles carrying microorganisms. (a) Upper region The above-mentioned particles are not present in the treated water treated from the tank, eliminating the need for a settling tank, and (b) biological treatment using particles carrying microorganisms, which significantly increases the concentration of microorganisms in the tank. (3) By using particles whose specific gravity is set in the range of 1 to 1.8, it is possible to reduce the processing time and the processing tank volume. This has advantages such as being able to reduce the energy required.

[Brief explanation of drawings]

1 to 3 are schematic configuration diagrams showing examples of a processing apparatus suitable for carrying out the processing method of the present invention, and FIGS. 4 and 5 are the processing apparatus shown in FIG. 3. FIG. 2 is a schematic configuration diagram showing a modification example of FIG. 1... Processing tank, 3... Stirrer, 5...
...Fluid-limited fluid, 6...Microorganism-carrying particles, 7.
... Overflow layer, 10 ... Sludge concentration meter or sludge interface meter, 11 ... Controller, 12 ...
・Intermediate fluid, 13... Gas injector, 15...
... Gas guide body, 16... Cylindrical layer. Figure 1 Written amendment to the procedures of B

Claims (1)

[Claims] When performing anaerobic treatment of wastewater by suspending particles carrying microorganisms in a treatment tank, the wastewater in the tank is divided into vertical directions of the tank, and the particles are substantially suspended in the upper part. An anaerobic treatment method for wastewater, which comprises forming a region below which the particles are suspended, and draining the treated water from the upper region where the particles are not substantially suspended.