JP2012239929A - Method and apparatus for anaerobic treatment of organic wastewater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for anaerobic treatment of high performance attaining long-term stable treatment of organic wastewater.SOLUTION: The method for biological anaerobic treatment of organic wastewater includes treating the organic wastewater through a first anaerobic treatment process 23 for eliminating easily-decomposable components in the organic wastewater by an upflow anaerobic sludge blanket method of holding granule sludge, and a second anaerobic treatment process 24 for eliminating hardly-decomposable components in effluent from the 23 by an anaerobic fixed filter bed method or a fluidized bed method using granular or powdery activated carbon. In the processes 23 and/or 24, treatment can be performed by circulating the effluent in the respective treatment processes, and apparatus used in the processes 23, 24 have baffle plates whose angles to the body side wall of the apparatus is 35° or less downward and whose occupied areas are at least half of the cross-sectional area of the apparatus.

Description

  The present invention relates to an anaerobic treatment method and apparatus for organic wastewater, and more particularly to an anaerobic treatment method and apparatus for biologically detoxifying organic wastewater containing a hardly decomposable component.

Organic wastewater may be decomposed and treated by anaerobic treatment. As such a decomposition treatment method, an anaerobic fixed filter bed method in which a filler is held in a reaction tank, an upflow anaerobic sludge bed method (hereinafter also referred to as UASB method), or a granular sludge expanded bed (hereinafter referred to as EGSB method). There are notes). The UASB method and the EGSB method have been widely used in recent years, and are characterized by maintaining a high concentration of methane bacteria in the reactor by granulating anaerobic bacteria such as methane bacteria into granules. As a result, even when the concentration of organic matter in the wastewater is considerably high, it can be treated efficiently. For example, an apparatus embodying this method is characterized in that it can be operated efficiently even when the volume load of COD _cr (hereinafter referred to as COD) measured using potassium dichromate as an oxidizing agent is 20 to 30 kg / m ³ / d. is there.

As a hardly decomposable substance having a slow decomposition rate in the anaerobic treatment process, chloroform, trichloroethylene, phenol, p-toluic acid, terephthalic acid, etc. are also easily degradable substances having a fast decomposition rate in the anaerobic treatment process. Acetic acid, saccharides, ethylene glycol, benzoic acid and the like are known. Refractory components are often contained in wastewater from chemical factories.
Conventionally, in the anaerobic treatment method, there have been very few examples of treating a hardly decomposable component, but in recent years, it is also possible to anaerobically decompose even a hardly decomposable component such as trichloroethylene, chloroform, phenol, terephthalic acid. It has become clear. In order to anaerobically decompose a hardly decomposable component, it is effective to perform a long-term treatment under anaerobic conditions.
As waste water containing a hardly decomposable component and an easily decomposable component, purified terephthalic acid production waste water is known. Acid [Sheng-Shung Cheng et al., Wat. Sci. Tech. , Vol. 36, 73-82 (1997)].

However, the method for anaerobically treating organic wastewater containing a hardly decomposable component has the following problems.
(1) In order to decompose and remove a hardly decomposable component, it is effective to perform a long-term treatment under anaerobic conditions. Therefore, even when an easily decomposable component is contained, the treatment is performed with a low load. Necessary and excessive facilities.
(2) When processing refractory components by the UASB method holding granule sludge, the refractory components in the wastewater tend to lower the immobilization capacity of microorganisms (methane bacteria) by self-granulation. In addition, it is difficult to form granular sludge, and the granular sludge is reduced in density, so that it is difficult to stably maintain the granular sludge for a long period of time, and as a result, it is difficult to continue the treatment.
(3) When the hardly decomposable component itself is an inhibitor for anaerobic microorganisms, it is necessary to perform dilution so that the hardly decomposable component is below the inhibitory concentration for the anaerobic microorganism.

Wat. Sci. Tech. , Vol. 36, 73-82 (1997)

  In view of the above-described prior art, an object of the present invention is to provide a high-performance anaerobic treatment method and apparatus capable of long-term stable treatment for organic wastewater.

In order to solve the above-mentioned problems, the present invention provides a method for biologically anaerobically treating organic wastewater, wherein the organic wastewater is treated with an upflow anaerobic sludge bed method in which granular sludge is retained. A first anaerobic treatment step for removing readily decomposable components in the wastewater, and an anaerobic fixed filter bed or fluidized bed using granular or powdery activated carbon from the effluent from the first step. According to the method, an anaerobic treatment method for organic wastewater is characterized in that it is treated with a second anaerobic treatment step for removing a hardly decomposable component in the effluent.
In the processing method, the first processing step and the second processing step can circulate a part of the effluent of each processing step to the respective processing step, and the second processing step. A part of the effluent can be circulated to the first treatment step.
Further, in the treatment method, a part of the effluent of the second treatment step in which the hardly decomposable component that is an obstacle for anaerobic microorganisms is decomposed and removed is less than the concentration at which the concentration of the hardly decomposable component inhibits the anaerobic treatment. By circulating to the upstream side of the first treatment step, it is possible to avoid inhibition of anaerobic microorganisms by a hardly decomposable component.

Further, in the present invention, in an apparatus for biologically anaerobically treating organic wastewater, the first of an upward flow anaerobic sludge bed holding granule sludge for removing easily decomposable components in the organic wastewater. And a second treatment device for an anaerobic fixed filter bed or fluidized bed using granular or powdery activated carbon that removes hardly decomposable components in the effluent from the treatment device. This is an anaerobic treatment device for organic wastewater.
In the processing apparatus, the first and second processing apparatuses are disposed on the main body side wall of the apparatus at an angle of 35 degrees or less downward with respect to the side wall, and each occupied area is a half of the cross-sectional area of the apparatus. A plurality of baffle plates as described above can be provided, and gas, liquid, and solid separation portions formed by the baffle plates can be provided in multiple stages, and the effluent of each treatment apparatus can be added to the treatment apparatus. It is possible to have a circulation path that circulates to each processing apparatus, and it is possible to have a circulation path that circulates a part of the effluent of the second treatment apparatus to the first treatment apparatus. In addition, it is possible to have an adjusting means for adjusting the amount of the circulating fluid so that the hardly decomposable component in the organic wastewater flowing into the first treatment apparatus is equal to or less than the concentration inhibiting the anaerobic treatment.

  The essence of the present invention is that a high-load treatment is carried out by an upward-flow anaerobic sludge bed holding granular sludge for the purpose of removing readily degradable components in organic wastewater in the first anaerobic treatment step, It is to remove the hardly decomposable components in the effluent from the first anaerobic treatment step by the second anaerobic treatment step which is an anaerobic fixed filter bed using powdered activated carbon or anaerobic fluidized bed. The high-performance anaerobic treatment for organic wastewater containing an easily decomposable component and a hardly decomposable component can be achieved. Furthermore, as an anaerobic treatment apparatus at that time, the main body side wall of the apparatus has a plurality of baffle plates having an angle with the side wall of 35 degrees or less and each occupation area being one half or more of the cross-sectional area of the apparatus, By using an upflow anaerobic treatment device that has multiple stages of gas, liquid, and solid separation parts formed by the baffle plate, the gas, liquid, and solid separation performance in the reactor is enhanced. It is possible to maintain a high concentration and to stably maintain granular or powdery activated carbon.

  In the present invention, in the first anaerobic treatment step, for the purpose of removing easily decomposable components in the organic wastewater, a high-load treatment is performed by an upward flow anaerobic sludge bed holding granular sludge, By removing the hardly decomposable components in the effluent from the first anaerobic treatment step by the second anaerobic treatment step which is an anaerobic fixed filter bed or anaerobic fluidized bed using granular or powdered activated carbon. In addition, as an anaerobic treatment apparatus at that time, a gas, liquid, or solid formed by a baffle plate whose angle with the side wall of the apparatus main body is 35 degrees or less and each occupied area is one half or more of the cross-sectional area of the apparatus. By using an upflow anaerobic treatment device with multiple separation sections, the gas / liquid / solid separation performance in the reactor is enhanced, so that the granular sludge is kept at a high concentration in the reactor, and granular Or stable maintenance of powdered activated carbon becomes possible It is possible to provide a processing method and apparatus to implement this the machine waste water.

The schematic block diagram which illustrated one form of the processing flow of this invention. The flow block diagram which illustrated one form of the upward flow anaerobic processing apparatus of this invention. The cross-sectional block diagram of the upward flow type anaerobic processing apparatus used for experiment. 1 is a schematic configuration diagram of a processing flow used in an experiment of Example 1. FIG. FIG. 5 is a schematic configuration diagram of a processing flow used in an experiment of Example 2.

Hereinafter, embodiments will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an embodiment of the treatment flow of the present invention, which is preferable for carrying out treatment of organic wastewater containing a hardly decomposable component.
In FIG. 1, 21 is raw water, 22 is an acid fermenter, 23 is an upflow anaerobic sludge bed treatment device (UASB) holding granule sludge, and 24 is an upflow anaerobic packed with granular or powdered activated carbon. Fluidized bed treatment apparatus (hereinafter also referred to as GAC), 25 is treated water, 26 is a UASB treated water circulation pipe, and 27 is a GAC treated water circulation pipe. In addition, you may use 24 as an anaerobic fixed filter bed of an upward flow or a downward flow.
The raw water 21 which is an organic wastewater containing a hardly decomposable component is subjected to an acid fermentation treatment in an acid fermentation tank 22 according to the properties of the raw water. The residence time in the acid fermenter is about 4 hours to 4 days. In the acid fermentation treatment, the effects of promoting the degradation of low-degradability components in raw water and reducing the molecular weight are small, but they are effective for improving the treatment efficiency with UASB. Since the pH suitable for the methane fermentation treatment is 6-8, the acid fermentation tank 22 adjusts the pH using a neutralizing agent such as NaOH. When acid fermentation treatment is not performed, a pH adjustment tank for pH adjustment may be provided between the raw water 21 and the UASB 23.

The anaerobic treatment of the present invention covers anaerobic treatment in all temperature ranges, such as a medium temperature methane fermentation treatment with an optimum temperature of 30 ° C. to 35 ° C., and a high temperature methane fermentation treatment with an optimum temperature of 50 ° C. to 55 ° C. It is said.
As a first anaerobic treatment step for mainly treating readily degradable components in raw water, the UASB method or EGSB method holding granule sludge is effective. Compared with other treatment methods such as anaerobic filter bed method and anaerobic fluidized bed method, UASB23 has a large amount of anaerobic bacteria, so it can be treated with a high COD load of 20 kg / m ³ / d or more. It becomes.

  As a second anaerobic treatment step for anaerobically treating the hardly decomposable components of the UASB 23 effluent, GAC24 using granular activated carbon as a carrier is effective. Granular activated carbon adsorbs difficult-to-decompose components due to the adsorption action of activated carbon, and anaerobic bacteria that adhere and proliferate on the activated carbon enable adsorption decomposition that is performed for a long time under anaerobic conditions. It becomes possible. Therefore, granular activated carbon has a greater effect of removing hardly decomposable components than other carriers such as plastic carriers. The effective diameter of the granular activated carbon is 0.05 mm to 3 mm, preferably 0.1 mm to 1 mm, more preferably 0.2 mm to 0.7 mm, and the uniformity coefficient is 1.2 to 2.0. In addition, when applying the UASB method in which granular sludge is retained in the second anaerobic treatment step, the hardly decomposable component in the wastewater relatively lowers the immobilization ability by self-granulation of microorganisms (methane bacteria). This makes it difficult to form granulated sludge, and also reduces the granular sludge density, making it difficult to maintain stable granulated sludge for a long period of time. Become.

FIG. 2 is a flow diagram illustrating an embodiment of the upward flow anaerobic treatment apparatus of the present invention that is preferable for carrying out the anaerobic treatment method. The reactor 2 of the upward flow anaerobic treatment apparatus is composed of granules. A GAC filled with UASB holding granular sludge and granular activated carbon.
One end is fixed to each of the left and right side walls inside the cylindrical reactor 2 which is in communication with the liquid feed pipe 1 to be treated and closed up and down, and the other end faces toward the opposite side wall. A baffle plate 3 extending while descending is installed. The baffle plates 3 are provided alternately at two left and right locations in the vertical direction, and form acute slanted section sludge zones 4a to 4b between the reactor side walls. The angle θ between the side wall of the reactor 2 and the baffle plate 3 is an acute angle of 35 degrees or less, and the occupied area is ½ or more of the cross-sectional area of the reactor 2. In the case of an angle exceeding 35 degrees, granular sludge or granular activated carbon is deposited on the baffle plate 3 in the sludge zones 4a and 4b, resulting in insufficient fluidity and a dead space. On the other hand, when the occupied area of the baffle plate 3 is 1/2 or less, the trapping of the generated gas becomes insufficient, causing a problem in the separation of gas and liquid. That is, the gas escapes upward from the center of the reactor 2, and the gas cannot be sufficiently accumulated in the GSS unit 5 described later.

The upper part of the divided sludge zones 4a and 4b forms a GSS portion 5. In the gas phase part 5a where the generated gas collects when the reaction starts, an outlet of the generated gas recovery pipe 6 communicating with the outside is provided.
In addition, the discharge port of the generated gas recovery pipe 6 connected from the gas phase part 5a is opened in the water of the water-sealed tank 7 filled with water. The opening position is at an appropriate water depth with different water pressure, and the water sealing tank 7 is provided with a gas meter 8 for measuring the flow rate of the gas discharged from the generated gas recovery pipe 6. A gas holder 11 is provided at the tip of the gas meter 8. A treated water pipe 9 for discharging the supernatant liquid is opened at the upper end of the reactor 2. In addition, 16 shows the upper end part by which granule sludge or activated carbon is hold | maintained.

  In the reactor 2, organic waste water is decomposed by the presence of granular sludge made of anaerobic bacteria and granular activated carbon holding the anaerobic bacteria, and biogas is generated. The generated gas is collected separately in the GSS part 5 at the upper end of each of the divided sludge zones 4a to 4b, forms a gas phase part 5a in each, and reaches the water seal tank 7 through the generated gas recovery pipe 6. The amount of such generated gas is recorded by the gas meter 8 and sent to the gas holder 11. Part of the generated gas adheres to the granular sludge or granular activated carbon in the divided sludge zones 4a to 4b, reduces the apparent specific gravity, and accompanies the granular sludge or granular activated carbon to the water surface of the GSS section 5. . Such generated gas forms bubbles and temporarily stays in the water surface bubble portion 5b. The air bubbles gathered in the water surface bubble portion 5b eventually burst, and the generated gas and granular sludge or granular activated carbon are separated. The granular sludge or granular activated carbon recovers its original specific gravity and dives into the water. It is discharged out of the system from the generated gas recovery pipe 6 via the water seal tank 7. The organic matter is decomposed and clarified, and the water is discharged out of the system via the treated water pipe 9 from the upper end of the reactor.

Since the gas pressure in the gas phase part 5 a of each GSS part 5 is different, the differential pressure may be adjusted in the water-sealed tank 7. It is necessary to keep the water sealing pressure higher in the order closer to the liquid feed side. There are many methods for adjusting the pressure for gas recovery in addition to the method using the water-sealed tank 7. For example, a pressure valve or the like may be used. In the anaerobic treatment method of the present invention, the generated gas generated in each sludge zone can be recovered, so that the generated gas amount per reactor unit cross-sectional area is reduced. In particular, the gas amount per unit cross-sectional area of the reactor becomes small at a place closest to the treated water pipe 9 through which treated water flows out. Therefore, the outflow amount of granule sludge and granular activated carbon can be extremely reduced.
The water to be treated is appropriately diluted as necessary with circulating water from UASB treated water or GAC treated water, or dilution water supplied from outside the system, and the flow rate of water in the reactor 2 is adjusted. To do. In a UASB reactor in which the GSS section is installed in multiple stages, the flow rate of the granular sludge layer is improved by setting the water flow rate to 1 to 5 m / h. In a GAC reactor in which the GSS section is installed in multiple stages, By setting the water speed to 2 to 10 m / h, the fluidized state of the granular activated carbon packed bed is improved.

The UASB and GAC COD volume load is determined by the organic matter components in the raw water and the ratio of easily decomposable and hardly decomposable components in the raw water, and the UASB and GAC capacities are determined. In many cases, it is difficult to pass water at an appropriate water flow rate by passing water at an appropriate amount. In other words, when the raw water is passed through the UASB and GAC temporarily, or when the circulating water of the raw water and the GAC treated water is passed through the UASB and the GAC, both the UASB and the GAC may be passed at an appropriate flow rate. Often difficult. Therefore, it is effective to circulate the UASB treated water circulating liquid to the UASB inflow portion and the GAC treated water to the GAC inflow portion as means for passing each of the UASB and GAC at an appropriate water flow rate.
In the case where the hardly decomposable component in the raw water is an obstacle for anaerobic microorganisms, the concentration of the inhibitory organic substance flowing into the UASB and the GAC is circulated by circulating the GAC treated water from which the hardly decomposable component is decomposed and removed to the UASB inflow portion ( Inhibitory to anaerobic microorganisms in UASB and GAC can be avoided by setting the inhibitory hardly decomposable component concentration) to an inhibitory concentration or less for anaerobic microorganisms. Even when the GAC treated water is circulated to the UASB inflow section, the UASB treated water circulating liquid is circulated to the UASB inflow section and the GAC treated water is circulated to the GAC inflow section. It is an effective means for watering.

The amount of circulating water to the UASB inflow part of the GAC treated water for making the inhibitory organic substance concentration below the inhibitory concentration for anaerobic microorganisms is adjusted by the following method.
• Obtain the inhibitory concentration (C ₀ ) of the target organic substance in advance by a batch test or the like.
・ The concentration of inhibitory organic substances flowing into UASB was measured for raw water (C _in ) and GAC treated water (C _out ), and the concentration of inhibitory organic substances (C) at the UASB inflow section was C ₀ or less based on the following formula. The circulating water amount (Q _r ) to the UASB inflow portion of the GAC treated water is set so that Inhibitory concentration of organic substances (C), it is necessary _{C 0} and less than equivalent, in practice it is preferable to C <1 / 2C _0.
C <C ₀ = (C _in × Q + C _out × Q _r ) / (Q + Q _r )
Q: Raw water quantity (m ³ / d)
Q _r : amount of circulating water to the UASB inflow part of GAC treated water (m ³ / d)
C, C ₀ , C _in , C _out : Inhibitory organic substance concentration or overall organic substance concentration (mg / L)

  In the case of foaming raw water, the gas phase portion 5a and the generated gas recovery pipe 6 in the GSS 5 are blocked, making it difficult to recover the generated gas. In such a case, foaming in the GSS 5 can be suppressed by adding the antifoaming agent 10 to the reactor 2 inflow water in advance. Compared to the method of dropping and spraying an antifoaming agent in GSS5, this method is more effective for defoaming in a sealed space. The antifoaming agent 10 has a defoaming effect according to the raw aqueous state, and loses the defoaming effect at an intermediate temperature (30 to 35 ° C.) or high temperature (50 to 55 ° C.) suitable for defoaming the fermentation broth. Use a defoamer with no air bubbles. As a kind of antifoaming agent, any of a silicone type antifoaming agent and an alcohol type antifoaming agent can be applied.

When scum is likely to be formed due to the influence of the raw water state or the like, scum is formed on the surface and inside of the bubble portion 5b in the GSS 5 and it becomes difficult to recover the generated gas. In such a case, the generated gas blowing pipe 13 is connected to the generated gas recovery pipe 6 or the diffuser pipe 12, and the generated gas in the gas holder 11 is supplied into the GSS 5 to prevent scum destruction or scum formation. Is possible.
When the generated gas blowing pipe 13 is connected to the generated gas recovery pipe 6 to destroy or remove the scum in the lower GSS 5, the valve 14 a is closed and the entire lower GSS 5 is used as the gas phase part 5 a, and the lower GSS 5 Discharge scum. Since this discharged scum stops in the lower GSS 5, the valve 14 b is closed, the entire upper GSS 5 is made the gas phase portion 5 a, and the scum is discharged from the upper GSS 5 and flows out together with the treated water.

  Further, when the generated gas blowing pipe 13 is connected to the diffuser pipe 12, the scum is broken by the bubbles blown from the diffuser pipe 12, and the broken scum is discharged as treated water together with the liquid flow in the reactor 2. . In the case of this method, the valve 14 can be opened and closed. When the valve 14 is opened and operated, the gas blown from the diffuser pipe 12 is recovered from the generated gas recovery pipe 6. When the valve 14 is closed and operated, in addition to the effect of destroying the scum due to the bubbles blown from the air diffuser 12, the effect of discharging the scum when the generated gas blowing pipe 13 is connected to the generated gas recovery pipe 6 can be expected. In addition, in order to destroy and remove the scum inside GSS5, the gas blown into GSS5 can be applied to a gas that does not contain oxygen such as nitrogen gas and does not affect biological treatment such as methane fermentation. It is desirable to use the generated gas. Although the frequency of blowing gas into the GSS 5 varies depending on the properties of the wastewater, it is effective to destroy and remove the scum inside the GSS 5 by changing it once a day to once a week.

Hereinafter, the present invention will be specifically described by way of examples.
Example 1
FIG. 3 shows a cross-sectional configuration diagram of the upward flow anaerobic treatment apparatus used in the experiment.
The apparatus 2 used in the experiment has the same structure, three inclined baffle plates 3 were attached, the angle θ between the apparatus side wall and the baffle plate was 30 degrees, and the antifoaming agent 10 was added to the raw water 1. The capacity of the liquid phase part of the device is 1 m ³ . The water temperature in the reactor is controlled to be 35 degrees.
As raw water, terephthalic acid production waste water (COD: 9000 mg / L) was added with inorganic nutrient salts (nitrogen, phosphorus, etc.) and the pH was neutralized to 7. The main components of raw water are p-toluic acid and terephthalic acid, which are hardly decomposable components, and easily decomposable acetic acid and benzoic acid.

FIG. 4 shows a schematic configuration diagram of the processing flow used in the experiment.
Series A was a GAC single treatment, in which GAC treated water was circulated and the water flow rate was set to 5 m / h.
Series B was UASB single treatment, UASB treated water was circulated, and the water flow rate was set to 2 m / h.
C series applied the UASB process to the first anaerobic treatment step and the second anaerobic treatment step. By circulating the treated water of UASB (1), the flow rate of UASB (1) is 2 m / h, and by circulating the treated water of UASB (2), the flow rate of UASB (2) is 2 m / h. Set to.
In the D series, UASB treatment was applied to the first anaerobic treatment step, and GAC treatment was applied to the second anaerobic treatment step. The flow rate of UASB was set to 2 m / h by circulating the treated water of UASB, and the flow rate of GAC was set to 5 m / h by circulating the treated water of GAC. The D series is a series based on the present invention.
In C series UASB (2), the amount of UASB (1) treated water flowing into UASB (2) was adjusted so as to achieve a predetermined COD load. Similarly, in the D-series GAC, the UASB treated water inflow amount to the GAC was adjusted so that a predetermined COD load was obtained.

Tables 1 and 2 show the processing results. Note that the COD removal rate of the C-series UASB (2) and the D-series GAC is the removal rate of the raw water COD.
(1) A series (GAC alone)
After 300 days, the COD removal rate was 78% at a COD load of 5 kg / m ³ / d, but after 400 days, the COD removal rate was 61% when treated at a COD load of 10 kg / m ³ / d. Declined.
(2) B series (UASB alone)
After 300 days, the COD removal rate was 68% with a COD load of 5 kg / m ³ / d, but the granule sludge decreased to about two-thirds at the start of the treatment. After 400 days, the granule sludge was reduced to about one third of that at the start of the treatment, so the treatment was continued at a COD load of 5 kg / m ³ / d, but the COD removal rate was lowered to 38%.

(3) Series C [UASB (1) + UASB (2)]
In UASB (1), the treatment with a COD removal rate of 50% was stably performed at a COD load of 60 kg / m ³ / d after 300 days to 400 days, but in UASB (2), the granule is similar to the B series. A decrease in the amount of sludge was observed and the treatment was continued at a COD load of 5 kg / m ³ / d, but the COD removal rate decreased from 72% after 300 days to 61% after 400 days.
(4) D series UASB was able to stably perform a COD removal rate of 50% with a COD load of 60 kg / m ³ / d after 300 to 400 days. In GAC, after 300 days, the COD removal rate was 80% at a COD load of 10 kg / m ³ / d, and after 400 days, the COD removal rate was 81% at a COD load of 15 kg / m ³ / d.

In B series UASB and C series UASB (2), three sloping baffle plates were attached and the granule sludge decreased despite the increased sludge retention effect. It was difficult to continue the stable treatment.
In the A series, stable processing can be continued, but it is necessary to operate with a low load of COD load of 5 kg / m ³ / d.
Compared to the A to C series, the D series which is the method of the present invention is capable of maintaining stable processing performance, exhibits high COD removal performance, and is a space-saving processing method.

Example 2
FIG. 3 shows a cross-sectional configuration diagram of the upward flow anaerobic treatment apparatus used in the experiment.
The apparatus 2 used in the experiment has the same structure, three inclined baffle plates 3 were attached, the angle θ between the apparatus side wall and the baffle plate was 30 degrees, and the antifoaming agent 10 was added to the raw water 1. The capacity of the liquid phase part of the apparatus is 100L. The water temperature in the reactor is controlled to be 35 degrees.
In the raw water, inorganic nutrient salts (nitrogen, phosphorus, etc.) are added to waste water (COD: 9000 mg / L, phenol concentration: 1200 to 2000 mg-COD / L) obtained by adding acetic acid to phenol-containing waste water, and the pH is adjusted to 7. The sum was used. The main components of the raw water are the hardly decomposable component phenol and easily degradable acetic acid. Phenol, which is a hardly decomposable component, becomes an inhibitor for anaerobic microorganisms when the concentration is high. In the case of this wastewater, it was confirmed by a batch test that the range of phenol concentration inhibition was 1000 mg / L or more in terms of COD.

FIG. 5 shows a schematic configuration diagram of a processing flow used in the experiment.
In the E series, UASB treatment was applied to the first anaerobic treatment step, and GAC treatment was applied to the second anaerobic treatment step. The flow rate of UASB was set to 2 m / h by circulating the treated water of UASB, and the flow rate of GAC was set to 5 m / h by circulating the treated water of GAC.
In the F series, as in the E series, the UASB process was applied to the first anaerobic treatment process and the GAC process was applied to the second anaerobic treatment process. In the F series, the GAC treated water was circulated to the first anaerobic treatment step, and the GAC treated water circulation amount was adjusted so that the first treatment step inflow phenol concentration was 500 mg-COD / L or less. The flow rate of UASB was set to 2 m / h by circulating the treated water of UASB, and the flow rate of GAC was set to 5 m / h by circulating the treated water of GAC.
Note that the amount of UASB treated water flowing into the GAC was adjusted so that the GAC had a predetermined COD load for both the E and F series.
For both E series and F series, GAC was adapted in advance so that the phenol decomposition removal treatment could be sufficiently performed.

Table 3 shows the results of processing results. Note that the ED and F series COD removal rates are the removal rates obtained from the raw water COD and the GAC treated water COD.
(1) E series In UASB, when the COD load was 3 kg / m ³ / d or more, the treatment tended to deteriorate due to the influence of the inhibition of the phenol concentration. Therefore, the COD load was processed at ³ kg / m ³ / d. In GAC, since the inflow of organic matter that has not been decomposed by UASB increases, it was necessary to perform treatment at a low load of COD load of 1 kg / m ³ / d. At this time, the GAC-treated water COD was 800 mg / L and the GAC-treated water phenol concentration was 5 mg / L.
(2) F series A part of the GAC treated water was circulated to the UASB inflow part as a circulating liquid. The circulation amount of the GAC treated water was twice the amount of raw water (2Q). By circulating the GAC-treated water to the UASB inflow part, the phenol concentration in the UASB inflow part became 403 mg-COD / L, and was not affected by the concentration inhibition of phenol. Therefore, in UASB, COD load 30 kg / m ³ / d, GAC COD load 6 kg / m ³ / d can be processed, GAC treated water COD 800 mg / L, GAC treated water phenol concentration 5 mg / L It was processing.

In E series, GAC treated water COD 800 mg / L and GAC treated water phenol concentration 5 mg / L could be continued, but the COD load in UASB was 3 kg / m ³ / d, and the COD load in GAC was 1 kg / L. It was necessary to carry out the treatment with a low load at m ³ / d.
On the other hand, in the F series in which inhibition of phenol concentration can be avoided by circulating the GAC treated water to the UASB inflow portion, the COD load in UASB is 30 kg / m ³ / d, and the COD load in GAC is 6 kg / m ^3. This is a processing method that can achieve high load processing of / d.
When the hardly decomposable component causes concentration inhibition for anaerobic microorganisms, the GAC treated water from which the hardly decomposable component is decomposed and removed is circulated to the UASB inflow portion, and the concentration of inhibitory organic substances flowing into the UASB and GAC (inhibitory difficulty) By making the degradable component concentration) below the inhibitory concentration for anaerobic microorganisms, an F-series treatment system capable of avoiding the inhibition of anaerobic microorganisms inside UASB and GAC is effective.

  1: Stock solution feed pipe, 2: Upflow anaerobic treatment device reactor, 3: Baffle plate, 4a-4b: Sludge zone, 5: GSS part, 5a: Gas phase part, 5b: Bubble part, 6: Generated gas Recovery pipe, 7: water sealing tank, 8: gas meter, 9: treated water pipe, 10: antifoaming agent, 11: gas holder, 12: air diffuser, 13: pipe, 14a, 14b: valve, 21: raw water, 22 : Acid fermenter, 23: Upstream anaerobic sludge bed treatment device (UASB), 24: Upflow anaerobic fluidized bed treatment device (GAC), 25: Treated water, 26: UASB treated water circulation piping, 27: GAC Treated water circulation piping

Claims (9)

  In the method of biologically anaerobically treating organic wastewater, the organic wastewater is freed from easily decomposable components in the organic wastewater by an upflow anaerobic sludge bed method holding granular sludge. The first anaerobic treatment step, and the effluent from the first step is subjected to an anaerobic fixed filter bed method or fluidized bed method using granular or powdered activated carbon, or a hardly decomposable component in the effluent solution. An anaerobic treatment method for organic wastewater, characterized in that it is treated with a second anaerobic treatment step for removing water.   The said 1st and / or 2nd anaerobic process process circulates and processes a part of effluent of each said process process to this each process process, The process of Claim 1 characterized by the above-mentioned. Anaerobic treatment method for organic wastewater.   The method for anaerobic treatment of organic wastewater according to claim 1 or 2, wherein a part of the effluent of the second anaerobic treatment step is circulated to the first anaerobic treatment step.   Circulation of a part of the effluent from the second anaerobic treatment step to the first anaerobic treatment step is such that the concentration of the hardly decomposable component in the organic wastewater flowing into the first anaerobic treatment step is anaerobic. The method for anaerobic treatment of organic wastewater according to claim 3, wherein the amount of the circulating fluid is adjusted so as to be equal to or less than a concentration that inhibits the sexual treatment.   In an apparatus for biologically anaerobically treating organic wastewater, a first treatment apparatus for an upflow anaerobic sludge bed holding granular sludge for removing readily decomposable components in the organic wastewater, An organic anaerobic wastewater having an anaerobic fixed filter bed or fluidized bed using granular or powdered activated carbon for removing hardly decomposable components in the effluent from the treatment apparatus Anaerobic treatment device.   The first and second processing apparatuses are provided on the side wall of the main body of the apparatus so that the angle with the side wall is 35 degrees or less downward and each occupation area is one half or more of the cross-sectional area of the apparatus. 6. The anaerobic treatment apparatus for organic wastewater according to claim 5, wherein a plurality of plates are provided, and gas, liquid and solid separation portions formed by the baffle plates are provided in multiple stages.   The said 1st and 2nd processing apparatus has a circulation path which circulates a part of effluent from each said processing apparatus to each said processing apparatus. Anaerobic treatment equipment for organic wastewater.   The said 2nd processing apparatus has a circulation path which circulates a part of effluent from this 2nd processing apparatus to said 1st processing apparatus. Anaerobic treatment equipment for organic wastewater.   In the circulation path for circulating a part of the effluent from the second treatment device to the first treatment device, the concentration of the hardly decomposable component in the organic wastewater flowing into the first treatment device is: 9. The anaerobic treatment apparatus for organic wastewater according to claim 8, further comprising an adjusting means for adjusting the amount of the circulating fluid so as to be equal to or less than a concentration that inhibits the anaerobic treatment.