JP2014223574A - Silicone removal device, biological treatment system, and silicone removal method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silicone removal device, a biological treatment system, and a silicone removal method, capable of removing silicone in drain water, with suppressed increase in operation costs.SOLUTION: Drain water is contacted with active sludge, so that silicone in the drain water is adsorbed to the active sludge. The active sludge to which silicone is adsorbed is then separated from the drain water. No preparation of chemicals is required for the removal of silicone, so that the increase in operation costs can be suppressed.

Description

  The present invention relates to a silicone removal apparatus, a biological treatment system, and a silicone removal method for removing silicone from waste water.

  Conventionally, there is a technique for reducing the silicone concentration in waste water by aerobic treatment of waste water containing silicone (eg, silicone oil, siloxane, etc.) using activated sludge. Moreover, in order to remove siloxane which is a volatile component volatilized from waste water, a gas component containing siloxane is introduced into an activated carbon adsorption tower to adsorb the siloxane on activated carbon (for example, see Patent Document 1). Moreover, in patent document 1, the hydrogen peroxide water and iron salt were added to waste water, and the silicone in waste water was decomposed | disassembled by Fenton reaction.

JP 2010-247118 A

  However, in the technique described in Patent Document 1, it is necessary to prepare a hydrogen peroxide solution, an iron salt, and the like, so that an operating cost is required. Moreover, when performing aerobic treatment using activated sludge in order to remove silicone, it was necessary to secure a large site for arranging equipment such as an aeration tank.

  In addition, when anaerobic treatment is performed using granulated granule sludge, if the drainage contains silicone, the granule sludge is covered with silicone in a short period of time, so anaerobic treatment can be performed. There wasn't. In addition, when silicone is contained in the biogas generated by the anaerobic treatment, the biogas cannot be used as a fuel for an internal combustion engine or the like. For example, the siloxane contained in the biogas becomes silica (silicon dioxide) and may adhere to the wall surface of the combustion chamber of the internal combustion engine, leading to a decrease in performance. Moreover, in a boiler, when siloxane is contained in the biogas of fuel, it becomes difficult to ignite and there exists a possibility that combustion may become unstable.

  An object of this invention is to provide the silicone removal apparatus, biological treatment system, and silicone removal method which can suppress the increase in operation cost and can remove the silicone in waste water.

  The silicone removing apparatus of the present invention is a silicone removing apparatus that removes silicone from waste water. The adsorbing part that makes the waste water contact activated sludge to adsorb the silicone to the activated sludge, and the activated sludge that has adsorbed silicone into the solid liquid from the waste water. And a solid-liquid separation unit for separation.

  According to this silicone removing apparatus, the silicone can be removed from the waste water by bringing the waste water into contact with the activated sludge, adsorbing the silicone in the waste water on the activated sludge, and separating the activated sludge adsorbing the silicone from the waste water. it can. In this silicone removing apparatus, it is not necessary to prepare chemicals to remove silicone, so that an increase in operating cost can be suppressed.

  In addition, the present invention is a biological treatment system equipped with the above-described silicone removal device, containing granule sludge formed by granulating anaerobic sludge, introduced waste water discharged from the solid-liquid separation unit, It is characterized by including an anaerobic treatment section that performs anaerobic treatment by bringing the wastewater into contact with the granular sludge.

  According to this biological treatment system, since the above-described silicone removing device is provided, the wastewater is brought into contact with the activated sludge, the silicone in the wastewater is adsorbed to the activated sludge, and the activated sludge having adsorbed the silicone is separated from the wastewater. be able to. Thereby, an increase in operating cost can be suppressed and silicone can be removed from the waste water.

  An anaerobic treatment unit that performs anaerobic treatment by bringing granular sludge into contact with waste water is provided at the subsequent stage of the silicone removing device. The waste water from which the silicone has been removed by the silicone removing device is introduced into the anaerobic treatment section and subjected to anaerobic treatment. Since the waste water from which the silicone has been removed is introduced into the anaerobic treatment section, the silicone does not adhere to the granule sludge, and an anaerobic treatment using the granule sludge can be performed. Since the silicone in the waste water is removed before the anaerobic treatment, the treatment can be performed without exchanging the granular sludge, and an increase in cost can be suppressed.

  Since the concentration of siloxane contained in the biogas generated by the anaerobic treatment can be kept low, the inflow of silicone to other devices using the biogas can be suppressed.

  The biological treatment system may have a configuration in which an activated sludge supply pipe that supplies activated sludge composed of excess sludge to the adsorption unit is connected to the adsorption unit. Thereby, activated sludge which consists of excess sludge can be supplied to an adsorption part through activated sludge supply piping, and silicone can be made to adsorb | suck to the supplied sludge for adsorption. The sludge for adsorption supplied to the adsorption unit may be surplus sludge, activated sludge, agglomerated sludge, and mixed sludge in which these are mixed.

  Further, the present invention relates to a method for removing silicone from wastewater, wherein the wastewater is brought into contact with activated sludge, an adsorption step for adsorbing silicone on the activated sludge, and the activated sludge that has adsorbed silicone is solid-liquid separated from the wastewater. And a solid-liquid separation step.

  According to this silicone removal method, the activated sludge can be separated from the waste water by bringing the waste water into contact with the activated sludge, adsorbing the silicone to the activated sludge, and separating the activated sludge adsorbed on the silicone from the waste water. it can. In this silicone removal method, it is not necessary to prepare chemicals to remove the silicone, and therefore an increase in operating cost can be suppressed.

  According to the present invention, silicone can be removed while suppressing an increase in operating cost.

It is a schematic block diagram of the biological treatment system which concerns on one Embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals are used for the same elements, and duplicate descriptions are omitted.

  In the biological treatment system 1 shown in FIG. 1, a pretreatment unit (silicone removal device) 2 for removing silicone contained in organic wastewater is provided in front of the anaerobic treatment unit 3 and the aerobic treatment unit 4. . Examples of silicone contained in organic wastewater include silicone oil and siloxane.

  The organic wastewater is introduced into the dehydrator 5 through the raw water inflow pipe L0. In addition, an excess sludge supply pipe L105 is connected to the dehydrator 5. The surplus sludge supply pipe L105 connects the settling tank 102 of the aerobic processing unit 4 and the dehydrator 5. Excess sludge settled and separated in a sedimentation tank 102 to be described later is supplied to the dehydrator 5 through an excess sludge supply pipe L105.

  The dehydrator 5 is, for example, a centrifuge and performs solid-liquid separation. The dehydrator 5 is provided with a mixing tank, and the organic waste water and excess sludge supplied to the dehydrator 5 are mixed and contacted in the mixing tank, and the silicone in the organic waste water is adsorbed on the excess sludge. The excess sludge adsorbing silicone is centrifuged by the dehydrator 5 to remove moisture, and then discharged through the outlet pipe L100 connected to the dehydrator 5. The discharged excess sludge is disposed off site.

  As the dehydrator 5, a multiple disk dehydrator or a belt press may be used. The dehydrator 5 functions as an adsorption unit that adsorbs silicone to activated sludge and a solid-liquid separation unit that separates activated sludge adsorbing silicone from waste water.

  Instead of the dehydrator 5, a coagulation sedimentation tank may be applied to perform sedimentation separation to perform solid-liquid separation. In the case of applying a coagulation sedimentation tank, a mixing tank is provided in front of the coagulation sedimentation tank, and organic wastewater and excess sludge are mixed in the mixing tank to adsorb silicone to the excess sludge. In order to increase the separation efficiency in the coagulation sedimentation, an inorganic coagulant or coagulant aid (polymer) may be added to the organic waste water.

  A water supply pipe L1 is connected to the drain outlet of the dehydrator 5, and the organic waste water separated by the dehydrator 5 flows into the adjustment tank 9 through the water pipe L1. The adjustment tank 9 stores the organic waste water processed by the anaerobic processing unit 3, and is a tank for adjusting the flow rate. A water supply pipe L2 is connected to the outlet of the adjustment tank 9, and a pump P2 is provided in the water supply pipe L2. The wastewater stored in the adjustment tank 9 passes through the water supply pipe L2 and is supplied by the pump P2 and supplied to the anaerobic treatment unit 3.

  The anaerobic treatment unit 3 is provided with an acid generation tank 11 and an anaerobic treatment tank 12. The organic waste water is introduced into the acid generation tank 11 through the water pipe L2. In the acid generation tank 11, the organic matter contained in the organic waste water is decomposed into acetic acid and the like by the acid generating bacteria. In the acid generation tank 11, an alkali agent (for example, sodium hydroxide) may be added as a neutralizing agent. A water supply pipe L3 is connected to the drain outlet of the acid generation tank 11, and a pump P3 is provided in the water supply pipe L3. The organic waste water in the acid generation tank 11 is introduced into the anaerobic treatment tank 12 through the water pipe L3.

  A pipe L11 branched from the water supply pipe L3 downstream of the pump P3 is connected to the acid generation tank 11. A part of the organic wastewater sent by the pump P3 is returned to the acid generation tank 11 through the pipe L11, and a water flow is generated in the acid generation tank 11 to stir the organic wastewater.

  The anaerobic treatment tank 12 is a reaction tank that performs an anaerobic treatment by an EGSB (Expanded Granular Sludge Bed) method or a UASB (Upflow Anaerobic Sludge Blanket). An inflow portion 13 is provided at the lower portion of the anaerobic treatment tank 12. The inflow part 13 is connected to the water pipe L <b> 3 and allows the organic waste water W to flow into the anaerobic treatment tank 12. The inflow portion 13 is, for example, a pipe provided with holes at equal intervals in the longitudinal direction. In the anaerobic treatment tank 12, granular sludge formed by granulating anaerobic sludge is stored. The organic waste water W is anaerobically treated by anaerobic bacteria in the granular sludge by contacting the granular sludge. As such granular sludge settles and accumulates in the lower part in the organic waste water, a granular sludge layer 14 is formed in the lower part of the anaerobic treatment tank 12.

  In the anaerobic treatment tank 12, the organic wastewater W is introduced into the inside from the inflow portion 13 to cause upward flow, and the organic wastewater W is anaerobically treated through the organic wastewater W through the granular sludge layer 14. . On the upper part of the granular sludge layer 14, a liquid layer of organic waste water W that has passed through the granular sludge layer 14 and has undergone anaerobic treatment is formed. The organic wastewater W in the liquid layer includes granular sludge that is flowing due to the liquid flow, floating granular sludge that has floated from the granular sludge layer 14, and biogas generated by anaerobic treatment (for example, methane gas and Carbon dioxide). The floating granule sludge is one in which the granule sludge floats. For example, the gas sludge floats on the granule sludge or the gas is encapsulated therein.

  Further, a setra (three-phase separation unit) 18 for separating the organic waste water W, the floating granular sludge, and the biogas is disposed on the upper portion of the anaerobic treatment tank 12.

  An inlet 18 a for introducing the organic waste water W into the setra 18 is formed at the lower end of the setra 18. In order to guide the organic waste water W to the introduction port 18a, an introduction plate 19 installed along the bottom of the setra 18 is provided below the setra 18 and around the introduction port 18a. The introduction plate 19 is formed with a return port 19a for returning the organic waste water W that has not been introduced into the introduction port 18a downward. Further, a rectifying plate 20 for adjusting the flow of the organic waste water W returned through the return port 19 a of the introduction plate 19 is provided below the introduction plate 19.

  The organic waste water W flows upward through the granule sludge layer 14 and flows into an introduction path formed between the introduction plate 19 and the setra 18 by the introduction plate 19. Part of the organic waste water W that has passed through the introduction path rises and flows into the setra 18 from the introduction port 18a, and the rest flows downward from the return port 19a of the introduction plate 19.

  For example, a cylindrical side wall 18b is provided on the upper portion of the setra 18, and a treated water discharge portion 23 that forms an annular flow path is provided around the side wall 18b. The organic waste water W flowing into the setra 18 overflows from the side wall 18b of the setra 18 to the outside and is collected in the treated water discharge unit 23 as treated water. The treated water from the treated water discharge unit 23 is returned to the acid generation tank 11 through the treated water return path L4 connected to the treated water discharge unit 23. In the setra 18, a partition wall 24 is provided on the inner side of the side wall 18 b of the setra 18 so that the organic waste water flowing in from the introduction port 18 a does not directly flow into the treated water discharge part 23.

  In the anaerobic treatment tank 12, anaerobic treatment of the organic waste water W is performed, and biogas is generated. The biogas floats up to the liquid level and reaches the space above the anaerobic treatment tank 12. The biogas that has reached the top of the anaerobic treatment tank 12 is discharged through the gas recovery line L6 and recovered as fuel. The biogas can be forcibly discharged out of the anaerobic treatment tank 12 by suction and exhaust by driving the blower P6.

  The treated water return path L <b> 4 connects the treated water discharge part 23 of the anaerobic treatment tank 12 and the splitter part 25 of the acid generation tank 11. The splitter unit 25 is a bottomed cylindrical body that extends in the vertical direction inside the anaerobic treatment tank 12. The opening 25 a at the upper end of the splitter unit 25 is disposed above the liquid level of the acid generation tank 11. In addition, a communication pipe L5 for extracting treated water in the splitter unit 25 is connected to the lower part of the splitter unit 25.

  A certain amount of treated water in the splitter unit 25 is extracted and supplied to the aerobic processing unit 4 through the communication pipe L5. A part of the treated water in the splitter section 25 overflows from the opening 25a at the upper end, flows into the organic waste water in the acid generation tank 11, and is supplied to the anaerobic treatment tank 12 again. A part of the treated water discharged from the anaerobic treatment tank 12 is circulated.

  A gas recovery line L6 is connected to the upper part of the acid generation tank 11. The biogas accompanying the treated water supplied from the anaerobic treatment tank 12 is discharged from the upper part of the acid generation tank 11 and is supplied to other devices together with the biogas discharged from the anaerobic treatment tank 12 as fuel. used. Other devices to which biogas is supplied include boilers and internal combustion engines.

  The aerobic processing unit 4 is provided with an aeration tank 101 and a sedimentation tank 102. The treated water is introduced into the aeration tank 101 through the communication pipe L5. The aeration tank 101 decomposes organic components (BOD) by performing aerobic treatment (activated sludge treatment) by aeration to generate stable substances such as water, carbon dioxide, sulfate, nitrate, and to multiply sludge. A pipe L7 is connected to the drain outlet of the aeration tank 101, and the treated water aerobically treated in the aeration tank 101 is sent to the sedimentation tank 102 together with activated sludge (excess sludge).

  The sedimentation tank 102 is for solid-liquid separation of excess sludge and treated water, and sediments and separates excess sludge. The separated treated water is discharged out of the system through the treated water discharge pipe L8. Moreover, the sludge return line L104 is connected to the sedimentation tank 102, and the pump P104 is provided in the sludge return line L104. Excess sludge separated into solid and liquid in the sedimentation tank 102 passes through the sludge return line L104, is introduced into the communication pipe L5, and is supplied to the aeration tank 101.

  A part of the excess sludge extracted from the sedimentation tank 102 passes through the sludge supply line L105 branched from the sludge return line L104, and is supplied to the pretreatment unit 2 and used as sludge for adsorbing silicone.

  Next, the operation of the biological treatment system configured as described above will be described.

  The organic wastewater supplied to the biological treatment system 1 is introduced into the mixing tank of the dehydrator 5. The surplus sludge (activated sludge) is supplied to the mixing tank of the dehydrator 5 through the surplus sludge supply line L105, and the organic wastewater and the surplus sludge are mixed and contacted in the mixing tank, and the silicone in the organic wastewater. Adsorbs to activated sludge. The activated sludge having adsorbed silicone is dehydrated by the dehydrator 5 and then discharged as separated sludge and disposed of off-site. Thereby, silicone can be removed from organic wastewater.

  The organic waste water from which the silicone has been removed by the dehydrator 5 is introduced into the acid generation tank 11, decomposed into acetic acid and the like by the acid producing bacteria, and then introduced into the anaerobic treatment tank 12. In the anaerobic treatment tank 12, the organic waste water is anaerobically treated by anaerobic bacteria in the granular sludge. Thereby, treated water and biogas can be obtained.

  A certain amount of the treated water treated in the anaerobic treatment tank 12 is introduced into the aerobic treatment unit 4 at the subsequent stage. A part of the treated water in the anaerobic treatment tank 12 is returned to the acid generation tank 11 and again introduced into the anaerobic treatment tank 12 for anaerobic treatment.

  The treated water introduced into the aerobic treatment unit 4 is aerated in the aeration tank 101 and aerobically treated with activated sludge. The treated water after aerobic treatment in the aeration tank 101 and the activated activated sludge (excess sludge) are settled and separated in the settling tank 102. The supernatant water of the sedimentation tank 102 is discharged out of the system as treated water treated by the biological treatment system 1. The excess sludge precipitated in the settling tank 102 is extracted from the bottom and returned to the aeration tank 101 to be used for aerobic treatment. Further, the excess sludge is supplied to the pretreatment unit 2 in order to remove silicone from the organic wastewater.

  According to such a biological treatment system 1, the organic wastewater is brought into contact with the activated sludge, the silicone in the organic wastewater is adsorbed on the activated sludge, and the activated sludge adsorbing the silicone is separated from the organic wastewater. As it can, the silicone is removed. In this pretreatment part 2, since it is not necessary to prepare chemicals in order to remove silicone, an increase in operating cost can be suppressed.

  Since the organic waste water from which the silicone has been removed in the pretreatment unit 2 is introduced into the anaerobic treatment unit 3, the silicone does not adhere to the granule sludge and an anaerobic treatment using the granule sludge can be performed. . Thereby, processing can be performed without exchanging granular sludge, and an increase in operating cost can be suppressed.

  Since the biogas generated in the anaerobic treatment unit 3 is prevented from containing siloxane, the inflow of silicone into other devices using the biogas can be suppressed. Organic wastewater containing silicone can be used in a boiler or the like using biogas generated by anaerobic treatment in the biological treatment system 1 as fuel.

  The present invention is not limited to the above-described embodiment, and various modifications as described below are possible without departing from the gist of the present invention.

  In the above embodiment, surplus sludge generated in the aerobic treatment unit 4 of the biological treatment system 1 is returned to the pretreatment unit 2 and used for adsorption of silicone, but the activity supplied to the pretreatment unit 2 The sludge may be excess sludge generated in other biological treatment systems, or other activated sludge. The sludge supplied to the pretreatment unit 2 may be agglomerated sludge aggregated using a coagulant or a mixed sludge in which activated sludge and agglomerated sludge are mixed.

  In the biological treatment system 1, the aerobic treatment unit 4 is provided after the anaerobic treatment unit 3, but the treated water treated by the anaerobic treatment unit 3 may be supplied to other devices. Good.

  Moreover, in the said embodiment, although a part of the treated water anaerobically treated in the anaerobic treatment tank 12 is returned to the acid generation tank 11, the entire amount of treated water is circulated without circulating a part of the treated water. You may introduce into the aerobic processing part 4 of a back | latter stage. The removal rate in anaerobic treatment can be improved by increasing the amount of treated water and the number of circulations.

  Further, the biological treatment system 1 may be configured to include a flow rate adjustment control device that adjusts the amount of excess sludge supplied to the pretreatment unit 2. For example, the removal efficiency of silicone can be improved by providing a flow rate adjusting valve in the excess sludge supply pipe L105 to adjust the supply amount of excess sludge.

  DESCRIPTION OF SYMBOLS 1 ... Biological processing system, 2 ... Pre-processing part, 3 ... Anaerobic processing part, 4 ... Aerobic processing part, 5 ... Dehydrator, 9 ... Adjustment tank, 11 ... Acid production tank, 12 ... Anaerobic processing tank, 101 ... aeration tank, 102 ... precipitation tank.

Claims (4)

In a silicone removal device that removes silicone from wastewater,
An adsorbing part for bringing the waste water into contact with activated sludge and adsorbing the silicone onto the activated sludge;
And a solid-liquid separation unit for solid-liquid separation of the activated sludge adsorbing the silicone from the waste water. A biological treatment system comprising the silicone removal apparatus according to claim 1,
Anaerobic treatment in which anaerobic sludge is granulated to store granulated sludge, the wastewater discharged from the solid-liquid separator is introduced, and the wastewater is brought into contact with the granular sludge to perform anaerobic treatment. A biological treatment system comprising a unit.   The biological treatment system according to claim 2, wherein an activated sludge supply pipe that supplies the activated sludge composed of excess sludge to the adsorption unit is connected to the adsorption unit. In the silicone removal method of removing silicone from wastewater,
An adsorption step of bringing the wastewater into contact with activated sludge and adsorbing the silicone onto the activated sludge;
And a solid-liquid separation step of solid-liquid separating the activated sludge adsorbing the silicone from the waste water.

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