JP4468771B2 - Organic wastewater treatment equipment - Google Patents

Description

  The present invention relates to an organic wastewater treatment apparatus capable of highly treating organic wastewater such as a beer manufacturing factory containing a large amount of solids.

  In the treatment of organic wastewater discarded in fields such as sewage, human waste, beer production, food and livestock production, an energy-saving anaerobic treatment method has been frequently used in recent years. Above all, UASB type (Upflow Anaerobic Sludge Blanket: Upflow Anaerobic Sludge Blanket) or EGSB type (Expanded Granular Sludge Blanket: Expanded granular sludge blanket type) that uses granules (eg, granule methane bacteria) consisting of anaerobic microorganisms EGSB is the only difference that the flow rate of liquid in the sludge bed is faster than that of UASB, so the following will be described as an upflow anaerobic sludge bed) and the standard activated sludge method. Wastewater treatment methods are widely used that combine wastewater treatment with properties that enable river discharge.

  However, this method has a problem that the aeration power cost of air in the aerobic treatment is large and the amount of excess sludge increases.

As a method for improving this problem, a method has been proposed in which UASB type anaerobic treatments are connected in series (in series) and treated (for example, see Patent Document 1). In this method, two UASB processing tanks are connected, processed in the first stage processing tank, and then processed again in the second stage processing tank, so that the processing performance is anaerobic. It has an advantage that it is better than the first stage treatment, and the amount of sludge generation is smaller than that of the second stage aerobic treatment.
JP 2001-9494 A

  However, even in the conventional treatment means in which the anaerobic treatment tanks as described above are arranged in two stages, if the waste water to be treated contains a lot of organic solids, the solids are not digested and required. There is a problem that it is not possible to obtain the processing properties. That is, anaerobic treatment for organic solids may be insufficient or not performed at all, and a relatively large amount of organic solids may remain in the treated water. For this reason, a large amount of chemical oxygen demand (COD) that is a wastewater regulation substance, that is, a so-called COD substance remains, and there may be a situation in which the regulation value for direct discharge to a river or the like cannot be satisfied.

  This invention is made | formed in view of this situation, The objective is to provide the processing apparatus which can process highly even even the waste water containing many organic solid substances.

  The present invention is an organic wastewater treatment apparatus for anaerobically treating organic wastewater containing organic solids, using an anaerobic sludge for an acid generation tank and the organic wastewater discharged from the acid generation tank And anaerobic treatment tanks for anaerobic treatment are connected in series, and at least one of the anaerobic treatment tanks of the multi-stage anaerobic treatment parts is from the acid generation tank. An anaerobic treatment that has a waste water introduction section for introducing the discharged organic waste water and a side wall that defines a space for containing anaerobic sludge, and the introduced organic waste water flows upward through the anaerobic sludge. A solid-liquid separation unit, a solid-liquid separation unit, and a solid-liquid separation unit that separate solids from treated water that has been treated in the upward flow unit and passed over the upper end of the upward flow unit And a fluid circulation path for guiding the separated solid matter to the upward flow portion.

  According to this configuration, since the anaerobic processing units are connected in a plurality of stages, the processing performance is improved as compared with the anaerobic process of only one stage. Moreover, since each anaerobic process part is equipped with an acid production | generation tank, it can decompose | disassemble an organic component into an organic acid etc., and can perform the anaerobic process in an anaerobic process tank efficiently. And since at least one of each anaerobic treatment tank of a multi-stage anaerobic treatment part has a solid-liquid separation part, even if it is waste water containing many organic solids, a solid matter is effectively removed from treated water. It is possible to effectively reduce COD that is removed and wastewater is regulated. Moreover, since the solid-liquid separation part is provided integrally with the anaerobic treatment tank, it is not necessary to provide a separate solid-liquid separation tank, and the installation space can be reduced. Further, the solid-liquid separation unit separates solids from the treated water that has overflowed the upper end of the upward flow unit. For this reason, even if the solid material reaches the upper end of the upward flow portion, it is separated from the treated water thereafter, so that the separation performance can be ensured regardless of the vertical height of the upward flow portion. Therefore, the vertical height of the upward flow portion can be suppressed, and the entire anaerobic treatment tank can be reduced in height. In the present invention, the upper end of the upward flow portion refers to the end portion in the vertical direction of the member that partitions the space of the upward flow portion and is the highest position.

  In addition, since the anaerobic treatment tank is provided with a fluid circulation path, the solid matter separated in the solid-liquid separation part is returned to the upward flow part via a different path from the rising solid matter. Therefore, even if anaerobic sludge is contained in the separated solid matter, it becomes difficult for anaerobic sludge in the solid matter going downward and anaerobic sludge in the rising solid matter to mix. When the anaerobic sludge accommodated in the section is changed up and down, the activity of the anaerobic sludge is made uniform. Moreover, since a solid substance is returned to an upward flow part, it can prevent that the anaerobic sludge accommodated in the upward flow part flows out of a tank. In addition, the fluid circulation path is a path different from the upward flow section, and connects the upper part of the solid-liquid separation section and the wastewater introduction section, so it is affected by the upward flow in the upward flow section. Downflow will occur in the fluid circulation path. Therefore, the solid that settles in the fluid circulation path is smoothly guided downward by gravity and downward flow.

  In this case, the anaerobic treatment tank of at least the last anaerobic treatment unit of the multi-stage anaerobic treatment unit has a wastewater introduction part, an upward flow part, a solid-liquid separation part, and a fluid circulation path. Is preferred. According to this structure, since the anaerobic treatment tank of the last stage anaerobic treatment part has a solid-liquid separation part, the final treated water is a good treated water from which solids (sludge) is sufficiently separated. Become.

  In this case, for example, it is preferable to provide two stages of anaerobic processing units. By using two stages of anaerobic processing units, a processing apparatus having a relatively simple structure and high processing capability can be obtained.

  In this case, it is preferable that the fluid circulation path connects the solid-liquid separation part and the part above the part where the organic waste water in the upward flow part is introduced. According to this configuration, the fluid circulation path returns the solid matter to the portion above the wastewater introduction portion in the upward flow portion, so that the wastewater flow is not disturbed and the wastewater flows smoothly in the tank.

  In this case, the solid matter separated in the solid-liquid separation part of the anaerobic treatment tank of the anaerobic treatment part is provided with a solubilization treatment tank, and the solid matter solubilized in the solubilization treatment tank is provided. It is preferable to provide a line for returning to at least one of the multi-stage anaerobic treatment units.

  The solid matter can be reduced by solubilizing the solid matter in the solubilization treatment tank. Further, by returning the solubilized solid matter to the anaerobic treatment section by the line, the anaerobic microorganisms contained in the solid matter can be returned to the anaerobic treatment section and reused.

  In this case, it is preferable to provide a line for connecting at least two anaerobic treatment tanks of each of the plurality of anaerobic treatment units and exchanging anaerobic sludge in the anaerobic treatment tank. According to this configuration, by exchanging sludge between anaerobic treatment tanks, the amount of sludge in each anaerobic treatment tank can be adjusted, and the cells can be kept highly active, so the apparatus can be stabilized. It can be operated and good processing performance can be maintained.

  In this case, it is preferable that the fluid circulation path includes a tubular member extending from the solid-liquid separation part to a location above the waste water introduction part of the upward flow part. According to this configuration, the fluid circulation path can be configured simply by attaching a tubular member to the outside of the conventional anaerobic treatment tank, and the existing device can be easily remodeled to the device of the present invention. .

  According to the organic wastewater treatment apparatus of the present invention, even if the wastewater contains a lot of organic solids, the solids are effectively removed from the treated water, and COD and the like, which are regulated by wastewater, can be effectively reduced. Can do.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the same code | symbol is used for the same element and the overlapping description is abbreviate | omitted.

  FIG. 1 is a view showing an organic wastewater treatment apparatus according to the first embodiment of the present invention. As shown in FIG. 1, the organic wastewater treatment apparatus 100 in this embodiment includes an acid generation tank 14, an anaerobic treatment tank 16, an acid generation tank 18, an anaerobic treatment tank 20, and a solubilization treatment tank 22. Yes. The acid generation tank 14 and the anaerobic treatment tank 16 constitute the first stage anaerobic treatment section 10, and the acid production tank 18 and the anaerobic treatment tank 20 constitute the second stage anaerobic treatment section 12. The first stage anaerobic processing unit 10 and the second stage anaerobic processing unit 12 are connected in series in two stages.

  The acid generation tank 14 holds facultative anaerobic microorganisms that perform an acid fermentation reaction in a suspended state in the liquid phase, and can decompose an organic component into an organic acid (lower fatty acid) or the like. . The acid generation tank 14 is supplied with organic waste water containing solids. When large waste is contained in the waste water, the waste is first removed with a coarse screen or the like, and then organic Wastewater is supplied to the acid generation tank 14. In the acid generation tank 14, an organic substance or the like is generated by the decomposition of the organic substance and is acidified or alkalized. Therefore, a neutralizing agent such as an acid or an alkali is added according to the pH of the organic wastewater.

  The wastewater treated in the acid generation tank 14 is transferred to an anaerobic treatment tank 16 in which anaerobic granular sludge (hereinafter simply referred to as granule sludge) is held from a pipe (line) 24 via a wastewater introduction unit 26. Supplied. The anaerobic treatment tank 16 is an upward flow type anaerobic treatment tank such as a so-called UASB type or EGSB type. Organic matter in the wastewater is converted into methane gas or the like by the action of methane bacteria or the like in the granular sludge layer 28 formed in the anaerobic treatment tank 16. The generated gas such as methane is taken out via a pipe (line) 38.

  The anaerobic treatment tank 16 includes a three-phase separation unit 30 that performs three-phase separation of gas (methane gas or the like) -solid (granular sludge) -liquid (treated water). However, SS (Suspended Solid) in wastewater has a low density and is a solid with poor sedimentation, and therefore flows out of the anaerobic treatment tank 16 together with the treated water.

  Part of the treated water in the anaerobic treatment tank 16 is returned to the acid generation tank 14 via a pipe (line) 32, and the remainder is acid in the second stage anaerobic treatment part 12 via a pipe (line) 34. It is supplied to a generation tank 18 (also serving as a storage tank).

  In the present embodiment, since the rising speed of the liquid in the anaerobic treatment tank 16 is fast, there is almost no distinction between the sludge bed layer and the sludge blanket layer, and the fluidized granule sludge layer 28 mainly composed of only the sludge blanket layer. The SS in the wastewater flows out of the anaerobic treatment tank 16 without being retained by the granular sludge layer 28 in the anaerobic treatment tank 16.

  The effluent from the anaerobic treatment tank 16 is supplied to the acid generation tank 18 of the second-stage anaerobic treatment section 12 via a pipe (line) 34, and the remaining organic matter is converted into organic acid or the like. Similarly to the acid generation tank 14 of the first stage anaerobic treatment unit 10, the acid generation tank 18 is adjusted to a pH suitable for acid generation and subsequent methane fermentation, so that an acid or an alkali is added as necessary. Is done.

  The effluent water from the acid generation tank 18 is introduced into the bottom of the second anaerobic treatment tank 20 having the solid-liquid separation part 48 at the top via a pipe (line) 40, and subjected to anaerobic treatment again. A gas such as methane generated in the anaerobic treatment tank 20 is taken out via a pipe (line) 54.

  FIG. 2 is a diagram showing an anaerobic treatment tank having a solid-liquid separation unit according to the first embodiment of the present invention. The anaerobic treatment tank 20 is an upward flow type anaerobic treatment tank such as a so-called UASB type or EGSB type. The anaerobic treatment tank 20 has a quadrangular prism shape, and has a bottom wall 64, a side wall 66, and a top wall 68. The side wall 66 extends upward from the edge of the bottom wall 64. An upper end 70 of the side wall 66 is opened without contacting the upper wall 68. The side wall 66 defines a space for accommodating granule sludge, and constitutes an upward flow portion that performs anaerobic treatment by flowing organic waste water upward through the granule sludge. Hereinafter, the inner space surrounded by the side wall 66 is referred to as a flow path R1.

  A waste water introduction part 42 is provided so as to pass through the side wall 66 at the lower part of the upward flow part 44. The waste water introduction unit 42 introduces waste water supplied from the outside into the flow path R1. The wastewater introduction part 42 is provided with a number of water outlets 43, and waste water is ejected from these water outlets 43.

  The lower part of the flow path R1 is filled with granule sludge that becomes the granule sludge layer 46, and methanogenic bacteria exist therein. The methane-producing bacteria in the sludge of the granular sludge layer 46 anaerobically treats the wastewater introduced from the wastewater introduction unit 42, decomposes organic matter in the wastewater, and generates gases such as methane gas and carbon dioxide gas. The treated waste water (hereinafter referred to as “treated water”) is discharged to the outside of the anaerobic treatment tank 20 through the drain port 78. Further, gases such as methane gas and carbon dioxide generated by the decomposition of the organic matter are discharged to the outside of the anaerobic treatment tank 20 through the gas discharge port 80 provided in the upper wall 68.

  An intermediate wall 72 is disposed so as to surround the upper portion of the side wall 66, and extends downward from the upper wall 68. In addition, the outer wall 74 projects from the upper part of the side wall 66 in a coronal manner, surrounds the intermediate wall 72, and extends upward. The upper end of the outer side wall 74 is opened without contacting the upper wall 68. The lower end of the intermediate wall 72 is at a position lower than the upper end 70 of the side wall 66 and the upper end of the outer wall 74. Further, the upper end of the outer wall 74 is located slightly higher than the upper end 70 of the side wall 66. A trough portion 76 is provided on the outer wall of the outer side wall 74. The upper end of the trough portion 76 continues to the edge of the upper wall 68. A drain port 78 is formed through the side wall of the trough portion 76. Hereinafter, a space surrounded by the side wall 66 and the intermediate wall 72 is defined as a flow path R2, a space surrounded by the intermediate wall 72 and the outer wall 74 is defined as a flow path R3, and a space surrounded by the outer wall 76 and the trough portion 76 is defined as a flow path R3. Let it be channel R4. These flow paths R2, R3, and R4 constitute a solid-liquid separator 48.

  A tubular member (fluid circulation path) 50 extends from the lower ends of the flow paths R2 and R3 to the lower portion of the side wall 66. The tubular member 50 is provided so as to be exposed outside the side wall 66. The tubular member 50 guides the solid separated by the solid-liquid separation unit 48 to the upward flow unit 44. Hereinafter, the space of the hollow portion of the tubular member 50 is referred to as a flow path R5. One end of the flow path R5 is connected to the flow path R2 and the flow path R3 via the pipe inlet 49 of the tubular member 50. The other end of the flow path R5 is connected to the lower part of the flow path R1 via the tube outlet 51 of the tubular member 50. The pipe outlet 51 is provided above the wastewater introduction part 42.

  A drawing port (drawing path) 82 is provided in the lower part of the flow path R5. The extraction port 82 is connected to the valve 58, and the SS that has settled down the flow path R5 by opening the valve 58 passes through the extraction port 82 and is discharged to the outside of the anaerobic treatment tank 20.

  Hereinafter, the operation at the time of operation of the anaerobic treatment tank 20 will be described. During operation of the anaerobic treatment tank 20, wastewater is always introduced from the wastewater introduction part 42 into the flow path R1. Since the waste water is continuously introduced, the inside of the anaerobic treatment tank 20 is filled up to the height of the upper end of the outer wall 74, and the liquid level H is formed.

  The wastewater introduced from the wastewater introduction part 42 is ejected upward from the outlet 43, mixed with the sludge of the granular sludge layer 46, and subjected to anaerobic treatment with the sludge. The gas generated by the anaerobic treatment becomes bubbles and rises in the flow path R1. Due to the ejection from the water outlet 43 and the rise of the bubbles, an upward flow is generated in the flow path R1, and the wastewater flows upward. In this way, the flow path R1 constitutes the upward flow part, and the side wall 66 constitutes the side wall of the upward flow part. Further, the upper end 70 of the side wall 66 constitutes the upper end of the upward flow portion. While the wastewater flows upward in the flow path R1, the organic matter is decomposed by the sludge of the granular sludge layer 46, and the organic matter concentration decreases as the liquid level H is approached. Therefore, most of the liquid in the vicinity of the liquid level H is treated water with a low organic matter content.

  A part of the sludge (solid matter) is lifted by the gas bubbles adhering thereto and reaches the liquid level H. While the sludge floats on the liquid surface H, gas bubbles are separated from the sludge. Further, the sludge gathers together while floating on the liquid surface H, and the particles become large and become granular. The gas away from the sludge accumulates in the space between the liquid level H and the upper wall 68 and is discharged to the outside through the gas discharge pipe 80.

  The sludge that floats on the liquid surface H and flows over the upper end 70 of the side wall 66 is guided to the intermediate wall 72 together with the treated water, and flows along the flow path R2 sandwiched between the intermediate wall 72 and the side wall 66 together with the treated water to the flow path R5. Settle toward. Thus, the intermediate wall 72 functions as a guide plate.

  Since the sludge descending the flow path R2 is in a state where the gas bubbles are separated from each other, the sludge easily settles by gravity toward the flow path R5 through the pipe inlet 49 as it is. Further, since part of the treated water that has passed over the side wall 66 flows to the flow path R5, the sludge that settles in the flow path R5 is pushed away by the treated water and smoothly settles in the flow path R5. The remaining treated water passes over the upper end of the outer wall 74 through the channel R3 sandwiched between the intermediate wall 72 and the outer wall 74, and overflows to the channel R4 surrounded by the trough portion 76. The treated water overflowing into the flow path R4 is discharged to the outside of the anaerobic treatment tank 20 through the drain port 78. A part of the discharged treated water is returned to the acid generation tank 18 via a pipe (line) 52 shown in FIG. Further, the discharged treated water is discharged out of the processing apparatus 100 through the pipe (line) 56 shown in FIG. 1 and directly discharged out of the system, or further, if necessary, biological treatment, physicochemical treatment, etc. Is discharged after removing organic matter, nitrogen component and phosphorus component.

  Thus, the flow path R2, the flow path R3, and the intermediate wall 72 provided on the outer periphery of the upper end 70 constitute a solid-liquid separation section 48 that separates sludge and treated water.

  The sludge that has settled down the flow path R5 reaches the pipe outlet 51 and is returned to the upper side of the waste water introduction part 42 of the flow path R1. The sludge returned to the channel R1 contributes to the anaerobic treatment of the wastewater introduced from the wastewater introduction part 42 while rising again by the upward flow. Thus, the flow path R5 provided outside the flow path R1 constitutes a fluid circulation path that guides sludge downward.

  In the anaerobic treatment tank 20, since the solid-liquid separation unit 48 is provided integrally with a part of the treatment tank, it is not necessary to provide a separate solid-liquid separation tank, and the installation space can be reduced. Moreover, the solid-liquid separation part 48 of the anaerobic processing tank 20 isolate | separates sludge from the treated water which overflowed the upper end 70 of flow path R1. For this reason, even if the sludge reaches the uppermost part of the flow path R1, it is separated from the treated water thereafter, so that the separation performance can be ensured regardless of the vertical height of the flow path R1. Therefore, the height of the flow path R1 in the vertical direction can be suppressed, and the entire apparatus can be reduced in height. Further, since the anaerobic treatment tank 20 is provided with the flow path R5 as a fluid circulation path, it is returned to the flow path R1 through a path different from the sludge S returned downward and the rising sludge. . Therefore, it becomes difficult for the separated sludge and the rising sludge to coexist, and the sludge accommodated in the flow path R1 is always switched up and down, so that the activity of the sludge is made uniform. Moreover, since a solid substance is returned to the upward flow part 44, it can prevent that the anaerobic sludge accommodated in the upward flow part flows out of a tank. Further, since the solid matter is returned upward from the waste water introduction portion 42 of the upward flow portion 44, the water flow in the anaerobic treatment tank 20 is not disturbed, and the waste water flows smoothly.

  Further, the flow path R5 as the fluid circulation path is affected by the upward flow generated in the flow path R1, so that a downward flow is generated. Therefore, since the sludge that settles down the flow path R5 is smoothly guided downward by gravity and downward flow, for example, a pump for returning the sludge is not necessary, and the sludge S that is granulated at the liquid surface H is formed. There is no problem of being pulverized by a pump or the like.

  In the anaerobic treatment tank 20, the solid-liquid separation part 48 is provided on the outer peripheral part at the upper end of the flow path R1. For this reason, the gas adhering to the sludge as bubbles is separated from the sludge at the liquid surface H at the upper center of the flow path R1. As a result, the sludge loses buoyancy, sinks again, and is returned downward. In addition, the sludge that has not settled here and has flowed over the upper end 70 is less affected by gas buoyancy and easily settles. Therefore, the sludge and treated water are smoothly settled in the flow path R5, which is a fluid circulation path. And are separated efficiently. Moreover, in the anaerobic treatment tank 20, by providing the intermediate wall 72, sludge is efficiently introduced into the flow path R5 and efficiently guided downward.

Subsequently, the operation at the time when the wastewater has a low concentration (for example, COD _Cr ≦ 1500 ppm) will be described. Note that description of points that overlap with the above description is omitted.
When the low-concentration waste water W is introduced into the anaerobic treatment tank 20, the amount of gas generated by the anaerobic treatment in the upward flow portion 44 is small. For this reason, sludge is distributed below the center of the upward flow portion 44 even during operation, and there is little sludge reaching the liquid level H. Since it is operated in the state as described above, there is little sludge reaching the liquid level H, and the solid matter separated by the solid-liquid separation unit 48 is mostly occupied by SS contained in the wastewater.

  The SS separated by the solid-liquid separation unit 48 is introduced into the flow path R5 and stops near the lower part of the flow path R5. Since SS is contained in the wastewater and supplied into the anaerobic treatment tank 20, the SS near the lower portion of the flow path R5 gradually increases and the density increases. Therefore, the valve 58 is opened at every predetermined time, and the SS that is stopped near the flow path R5 is discharged from the extraction port 82 to the outside of the anaerobic treatment tank 20.

  The SS contained in the wastewater is not suitable for anaerobic treatment and is continuously supplied, and therefore accumulates in the anaerobic treatment tank 20. According to the anaerobic treatment tank 20 of the present embodiment, since the extraction port 82 is provided, the accumulated solid matter can be discharged to the outside, and excessive SS is accumulated in the anaerobic treatment tank 20. Can be prevented.

In addition, as described above, when the organic matter concentration of the wastewater to be treated is low, the amount of gas generated decreases, but in the anaerobic treatment tank 20, the generated gas is discharged from the gas discharge pipe 80 provided on the upper wall 68. The gas is discharged, and the gas is not removed except at the liquid level H. Therefore, according to the anaerobic treatment tank 20 of the present embodiment, gas is not removed in the middle of the upward flow portion 44, so that upward flow due to the gas lift effect is generated even when the amount of generated gas is small. It is formed. Therefore, the anaerobic treatment tank 20 of the present embodiment can be suitably applied to the treatment of wastewater with a low organic matter concentration, for example, COD _Cr ≦ 1500 ppm.

  Further, in the anaerobic treatment tank 20 of the present embodiment, the tubular member 31 serving as the fluid circulation path is provided to be exposed to the outside. For example, the tubular member is disposed in the flow path R1 as the upward flow portion. 31 may be incorporated. Alternatively, the fluid circulation path is not a tubular member, but an inner wall is provided in the anaerobic treatment tank 20 to have a structure having a double wall of the inner wall and the outer wall, and a space between the inner wall and the outer wall. It is good also as a structure which uses as a fluid circulation path.

  Returning to FIG. 1, the SS separated by the solid-liquid separation unit 48 of the anaerobic treatment tank 20 is supplied from the valve 58 to the solubilization treatment tank 22 via a pipe (line) 60. In the solubilization treatment tank 22, an alkaline agent such as NaOH is used as a solubilizing agent, and is maintained under alkaline conditions of about pH 10 to 13, and solubilizes SS. The solubilized solution is neutralized with HCl or the like as necessary, and then returned to the previous stage such as the acid generation tank 14 or the acid generation tank 18 through the pipe (line) 62 and processed. The In addition to the alkali treatment, the solubilization treatment can be carried out by acid treatment, ozone treatment, acid fermentation treatment, superheat treatment, ultrasonic treatment, or a combination of these treatments as appropriate.

  Moreover, in the processing apparatus 100 of this embodiment, the piping (line) 36 which connects the anaerobic processing tank 16 and the anaerobic processing tank 20, and replaces the anaerobic sludge of each anaerobic processing tank is provided. In the present embodiment, the SS in the wastewater flows out of the tank in both the first stage anaerobic treatment tank 16 and the second stage anaerobic treatment tank 20 and therefore does not accumulate in the tank. Therefore, since the granular sludge in the two anaerobic treatment tanks 16 and 20 is maintained in a good state, it is possible to mutually supply the granular sludge between the anaerobic treatment tanks 16 and 20. . The mutual supply of granule sludge is usually performed when the apparatus is stopped, but it can also be performed during operation.

  The anaerobic treatment tank 20 having the solid-liquid separation unit 48 in the upper part of the second stage has a low concentration of organic matter, so there is little increase in granulated sludge, and in some cases, there is a decrease in cell bodies due to autolysis of methane bacteria and the like. Since this occurs, the granular sludge in the first stage anaerobic treatment tank 16 is supplied via the pipe 36.

  On the contrary, the sludge is supplied by supplying the granular sludge of the second stage anaerobic treatment tank 20 having a low load of organic matter (in an oligotrophic state) to the first stage anaerobic treatment tank 16. The activity of can also be increased. By supplying sludge to each other in this way, the amount of sludge in the two tanks can be adjusted and the cells can be kept highly active. You can get water.

  In the above embodiment, an anaerobic two-stage process is shown as an example. However, in order to perform a more advanced process, three or more stages of anaerobic treatment units are connected to the series, and the anaerobic treatment tank in the final stage is connected. An anaerobic treatment tank having a solid-liquid separation part at the upper part can also be arranged and carried out.

  Hereinafter, the effect of this embodiment is demonstrated. In the upflow anaerobic sludge bed method using granulated sludge with good sedimentation formed by self-immobilizing methane bacteria, etc., the sludge bed layer and sludge blanket layer are in the anaerobic treatment tank. Since the sludge is retained in a state in which the sludge is formed, granule sludge hardly flows out together with the treated water, and the cell concentration of methane bacteria and the like in the anaerobic treatment tank can be maintained high. Therefore, it has the advantage that waste water can be treated at high load and high speed. However, since a considerable portion of the organic solids contained in the wastewater is generally difficult to digest, even if two or more anaerobic treatment tanks are connected and processed, they remain undecomposed.

  In an up-flow type anaerobic sludge bed, the flow of water in the anaerobic treatment tank is usually fast even though granule methane bacteria can be retained in the anaerobic treatment tank, and bubbles such as methane and carbon dioxide are generated. Therefore, the solid matter (mainly organic suspended solids) in the wastewater flowing into the anaerobic treatment tank flows out of the anaerobic treatment tank together with the treated water.

  Therefore, even if the soluble organic matter in the wastewater is effectively treated, the organic solid matter that is difficult to treat is included in the treated water, and there is a problem that COD, which is a wastewater regulating substance, remains considerably. .

  In the present embodiment, a compact anaerobic treatment tank having a solid-liquid separation unit capable of separating the treated water and SS is disposed at the upper part of the final stage anaerobic treatment tank. In this embodiment, since the treatment is performed in a plurality of stages, most of the organic substances (mainly soluble organic substances) are decomposed in the first stage, and the amount of gas generated is small in the anaerobic treatment tank in the second stage. Therefore, an increase in the rising flow rate of the liquid accompanying the rise of bubbles is suppressed, and since there is little gas adhering to the SS, the separation of the SS from the treated water at the second stage is performed well, and good treated water can get.

  Moreover, since the separated SS can be taken out as concentrated sludge outside the anaerobic treatment tank, and this concentrated sludge can be supplied to the solubilization treatment tank for treatment, the generated sludge can be reduced efficiently. Is possible.

  Another feature of the present embodiment is that the granular sludge in the first and second anaerobic treatment tanks is supplied to each other. As a result, it is possible to adjust the excess or deficiency of the granular sludge in each tank, and to make the granular sludge in the first and second anaerobic treatment tanks uniform, and further granule The activity of sludge can be kept high. Therefore, stable operation of the apparatus is possible and good processing can be performed.

  FIG. 3 is a view showing an organic wastewater treatment apparatus according to the second embodiment of the present invention. In the processing apparatus 200 of the present embodiment, the first-stage anaerobic processing unit 10 also includes the anaerobic processing tank 21 provided with the solid-liquid separation unit 48 in the upper part thereof, as compared with the apparatus of the first embodiment. Is different. By providing an anaerobic treatment tank equipped with a solid-liquid separation unit in both the first stage and the second stage anaerobic treatment part, SS is more efficiently separated from the treated water. Treated water is obtained.

  In the present embodiment, the SS separated in the two anaerobic treatment tanks 21 and 20 is solubilized by one solubilization treatment tank 22. The solubilized treatment liquid is returned to the first-stage acid generation tank 14 via the pipe 62. In this case, an individual solubilization treatment tank may be arranged for each anaerobic treatment tank.

  FIG. 4 is a view showing an organic wastewater treatment apparatus according to the third embodiment of the present invention. In the processing apparatus 300 of the present embodiment, the order of the first-stage anaerobic processing unit 10 and the second-stage anaerobic processing unit 12 is switched by arranging piping and valves that form a bypass path. This is different from the apparatus of the second embodiment.

  A valve 90 is provided between the pipes for supplying the waste water to the first-stage acid generation tank 14. A pipe (line) 84 for directly supplying wastewater to the second-stage acid generation tank 18 is provided, and a valve 91 is provided between the pipes 84. A valve 92 is provided between the pipes 34 through which the treated water treated by the first stage anaerobic treatment unit 10 passes. A pipe (line) 86 for discharging the treated water treated in the first stage anaerobic treatment unit 10 directly to the outside of the system is connected to the pipe 34, and a valve 93 is provided between the pipes 86. . A valve 94 is provided between the pipes 56 through which the treated water of the second stage anaerobic treatment unit 12 passes. A pipe (line) 88 for supplying the treated water treated in the second stage anaerobic treatment unit 12 to the first stage anaerobic treatment unit 10 is connected to the pipe 56. Is provided with a valve 95.

  When the processing apparatus 300 of the present embodiment is first operated, the valve 90, the valve 92, and the valve 94 are opened, and the valve 91, the valve 93, and the valve 95 are closed. Then, the wastewater flows in the order of the first-stage acid generation tank 14, the first-stage anaerobic treatment tank 21, the second-stage acid generation tank 18, and the second-stage anaerobic treatment tank 20. That is, the flow is the same as in the first embodiment and the second embodiment described above.

  On the other hand, when the order of the first-stage anaerobic processing unit 10 and the second-stage anaerobic processing unit 12 is switched, the valve 91, the valve 93, and the valve 95 are opened, and the valve 90, the valve 92, and Valve 94 is closed. In this way, the waste water is supplied directly to the second-stage acid generation tank 18 via the pipe 84 and is subjected to anaerobic treatment in the second-stage anaerobic treatment tank 20. The treated water treated in the second-stage anaerobic treatment tank 20 is supplied to the first-stage acid generation tank 14 via the pipe 88 and is anaerobic in the first-stage anaerobic treatment tank 21. It is processed. The treated water treated in the first stage anaerobic treatment tank 21 is discharged out of the system through the pipe 86. In this case, the waste water is in the order of the second-stage acid generation tank 18, the second-stage anaerobic treatment tank 20, the first-stage acid generation tank 14, and the first-stage anaerobic treatment tank 21. Will flow. That is, the second stage anaerobic processing unit 12 is the first stage, and the first stage anaerobic processing unit 10 is the second stage.

  As described above, in the first stage anaerobic treatment tank, the concentration of organic components in the wastewater is high, so methane bacteria increase, and in the second stage anaerobic treatment tank, the concentration of organic components in the wastewater. Is low, methane bacteria are reduced. However, by appropriately switching the first stage and the second stage as in the present embodiment, in each anaerobic treatment tank 21, 20, the increase / decrease of bacterial cells is repeated, and as a whole apparatus The amount of cells can be kept uniform and constant.

Example 1
An organic wastewater containing organic solids from a beer manufacturing plant having a composition as shown in FIG. 5 (I) is treated as a first-stage acid generation tank (effective volume) of the treatment apparatus as shown in FIG. 1m ³ ), anaerobic treatment was performed in an anaerobic treatment tank (effective volume 3.5 m ³ ), and part of the treated water in the anaerobic treatment tank was returned to the acid generation tank. The acid generation tank was adjusted to pH 7, and the inside of the anaerobic treatment tank was set to 38 ° C. The composition of the outflow water in the first stage anaerobic treatment tank at this time was as shown in (II) of FIG.

Further, the second stage anaerobic treatment having a solid-liquid separation unit is performed by supplying the effluent from the first stage anaerobic treatment tank to the second stage acid generation tank (effective volume 1 m ³ ). Anaerobic treatment was performed in a tank (effective volume 1 m ³ ).

  As a result of continuous operation for 6 months under the above conditions, there was no accumulation of SS in the first and second anaerobic treatment tanks, and smooth operation was possible. Further, the obtained treated water was good as shown in FIG.

(Comparative Example 1)
Using a processing apparatus including an anaerobic treatment tank having no solid-liquid separation unit, the same type as the first stage anaerobic treatment unit of Example 1 being connected in series to two stages, and Example 1 Organic wastewater was treated under the same conditions.

As a result of continuous operation for 6 months under the above conditions, the properties of the treated water in the second stage anaerobic treatment tank were as shown in (IV) of FIG. That is, by connecting the anaerobic treatment units in series and treating them in two stages, soluble organic matter can be treated efficiently, but SS in the treated water cannot be removed, so T-COD _Cr (total chemical oxygen demand) ) Could not be reduced satisfactorily.

  As described above, the multi-stage organic wastewater treatment apparatus according to the present embodiment has a simple solid-liquid separation unit that can reduce the equipment cost and the installation area as the final stage anaerobic treatment tank with less generation of bubbles. Since the solid matter is removed from the treated water simply by disposing the anaerobic treatment tank, the chemical oxygen demand (COD) and the like that are regulated by wastewater can be effectively reduced.

  In addition, since the two-stage anaerobic treatment is performed, a part of the solid is solubilized in the process, and only the remaining separated SS is solubilized. Since the amount of SS to be solubilized is small compared to the solubilization treatment, it is possible to reduce the load of solubilization such as reduction of the alkaline agent used for solubilization.

  The organic wastewater treatment apparatus of the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention.

It is a figure which shows the organic wastewater processing apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the anaerobic processing tank characterized by having the solid-liquid separation part which concerns on 1st Embodiment of this invention. It is a figure which shows the processing apparatus of the organic waste water which concerns on 2nd Embodiment of this invention. It is a figure which shows the processing apparatus of the organic waste water which concerns on 3rd Embodiment of this invention. It is a table | surface which shows the driving | operation result of the processing apparatus of the organic waste water in an Example and a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... First stage anaerobic processing part, 12 ... Second stage anaerobic processing part, 14 ... Acid production tank, 16 ... Anaerobic treatment tank, 18 ... Acid production tank, 20 ... Anaerobic treatment tank, DESCRIPTION OF SYMBOLS 21 ... Anaerobic processing tank, 22 ... Solubilization processing tank, 24 ... Pipe (line), 26 ... Waste water introduction part, 28 ... Granule sludge layer, 30 ... Three-phase separation part, 32 ... Pipe (line), 34 ... Piping (line), 36 ... Piping (line), 38 ... Piping (line), 40 ... Piping (line), 42 ... Waste water introduction part, 43 ... Outlet, 44 ... Upward flow part, 46 ... Granule sludge layer 48 ... solid-liquid separation part, 49 ... pipe inlet, 50 ... tubular member (fluid circulation path), 51 ... pipe outlet, 52 ... pipe (line), 54 ... pipe (line), 56 ... pipe (line), 58 ... Valve, 60 ... Piping (line), 62 ... Piping (line), 64 ... Bottom wall, 66 ... Side wall 68 ... Upper wall, 70 ... Upper end, 72 ... Middle wall, 74 ... Outer wall, 76 ... Trough part, 78 ... Drain port, 80 ... Gas outlet, 82 ... Drawer port, 84 ... Pipe (line), 86 ... Pipe (Line), 88 ... piping (line), 90, 91, 92, 93, 94, 95 ... valve, 100, 200, 300 ... processing device, R1, R2, R3, R4, R5 ... flow path, H ... liquid surface

Claims (7)

An organic wastewater treatment apparatus for anaerobically treating organic wastewater containing organic solids,
Anaerobic treatment units including an acid generation tank and an anaerobic treatment tank that anaerobically treats organic wastewater discharged from the acid generation tank using anaerobic sludge are connected in series in a plurality of stages,
At least one of the anaerobic treatment tanks of the multi-stage anaerobic treatment section is:
A wastewater introduction section for introducing organic wastewater that has flowed out of the acid generation tank;
An upward flow portion having a side wall that defines a space for accommodating the anaerobic sludge, and performing anaerobic treatment by causing the introduced organic wastewater to flow upward through the anaerobic sludge;
A solid-liquid separation unit that separates solids from treated water that has been treated in the upward flow part and overflowed the upper end of the upward flow part;
A fluid circulation path for guiding the solid separated by the solid-liquid separation unit to the upward flow part;
An organic wastewater treatment apparatus characterized by comprising:   The anaerobic treatment tank of the anaerobic treatment unit at least the last stage of the plurality of anaerobic treatment units includes the wastewater introduction unit, the upward flow unit, the solid-liquid separation unit, and the fluid circulation. The organic wastewater treatment apparatus according to claim 1, further comprising a path.   The apparatus for treating organic wastewater according to claim 1 or 2, comprising two stages of the anaerobic treatment section.   The fluid circulation path connects the solid-liquid separation part and a part above the part where the organic waste water is introduced in the upward flow part. The processing apparatus of the organic waste water of any one of thru | or 3 thru | or 3. A solubilization treatment tank for solubilizing the solid matter separated in the solid-liquid separation part of the anaerobic treatment tank of the anaerobic treatment part,
The line according to any one of claims 1 to 4, further comprising a line for returning the solid material solubilized in the solubilization tank to at least one of the plurality of anaerobic treatment units. The organic wastewater treatment apparatus as described in the paragraph.   The at least two anaerobic treatment tanks of each of the plurality of anaerobic treatment units are connected to each other, and a line for exchanging anaerobic sludge in the anaerobic treatment tank is provided. The organic wastewater treatment apparatus according to any one of the above.   7. The fluid circulation path includes a tubular member extending from the solid-liquid separation part to a location above the waste water introduction part of the upward flow part. The organic wastewater treatment apparatus as described in Item 1.

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