JP2019025430A - Method for treating digested sludge desorption liquid, treatment apparatus thereof, waste water treatment method and wastewater treatment apparatus - Google Patents

Abstract

To provide a method for treating digested sludge desorption liquid capable of stably treating digested sludge desorption liquid over a long term (nitrification and denitrification) using an aerobic granule, a treatment apparatus thereof, a wastewater treatment method and a waste water treatment apparatus.SOLUTION: A treatment apparatus for digested sludge desorption liquid comprises: an aerobic granule treatment tank 8; supply paths 26 and 17 for supplying digested sludge desorption liquid and concentrated dehydrated separation liquid of initial precipitation sludge to the aerobic granule treatment tank 8, respectively; an ammonia meter 27 and a TOC meter 18 as concentration measuring means for measuring the nitrogen concentration of the digested sludge desorption liquid and the carbon concentration of the concentrated dehydrated separation liquid of the initial precipitation sludge, respectively; and control means 30 for controlling the supply amount of the concentrated dehydrated separation liquid of the initial precipitation sludge so that the values of the carbon concentration/nitrogen concentration are in a predetermined range.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a digested sludge detachment liquid treatment method, a treatment apparatus thereof, a wastewater treatment method, and a wastewater treatment apparatus.

  For the purpose of treating organic components contained in raw water such as sewage and factory wastewater, an activated sludge method using assimilation and catabolism of microorganisms is widely used.

  Also disclosed is a method for forming an aerobic granule that can treat organic matter and can stably form granules (granular microbial sludge) under aerobic conditions with continuous water flow ( For example, see Patent Document 1). Furthermore, in Patent Document 1, it is described that it is preferable to adjust the C / N ratio (total organic carbon (TOC) / total nitrogen (TN)) of raw water continuously flowing to be 7 or less. .

  In addition, a wastewater treatment device and a wastewater treatment method that can stably form granules in a semi-batch biological treatment device and supply the granules to a continuous biological treatment device are also disclosed (for example, Patent Document 2). reference). Furthermore, in Patent Document 2, semi-batch organisms that form granules by performing biological treatment by intermittently introducing desorbed water obtained from at least one of concentration, digestion, and dehydration of surplus sludge. A processing device is described.

JP 2009-66505 A Japanese Patent Laid-Open No. 2006-87595

  However, when the C / N ratio (total organic carbon (TOC) / total nitrogen (TN)) of the raw water is increased toward 7, as in the technique disclosed in Patent Document 1, the activity of nitrifying bacteria is increased. As a result, not only aerobic granules but also various bacteria other than aerobic granules are likely to be generated, and the aerobic granules become unstable and long-term operation becomes impossible.

  In addition, in the technique disclosed in Patent Document 2, it is also described that desorbed water obtained from the digestion process of excess sludge is introduced into a semi-batch biological treatment apparatus, but this is only the semi-batch biological treatment. It is premised on supplying granules discharged from the apparatus to the continuous biological treatment apparatus.

  Therefore, there is no reference as to how to stably treat (nitrify and denitrify) the desorbed water obtained from the digestion of excess sludge (referred to as “digested sludge desorbed liquid”). Naturally, there is no mention of how to treat the treated water other than simply treating the treated water as a wastewater treatment apparatus.

  An object of the present invention is to provide a digested sludge desorbed liquid treatment method capable of stably treating (denitrifying and denitrifying) long-term digested sludge desorbed liquid using an aerobic granule, its treatment apparatus, and wastewater treatment. The object is to provide a method and a wastewater treatment apparatus.

In order to achieve this object, a method for treating a digested sludge desorption liquid according to the first invention comprises:
A supply step of supplying a digested sludge desorption liquid and a concentrated dewatered separation liquid of primary settled sludge to a treatment tank containing aerobic granules;
A concentration measuring step for measuring the nitrogen concentration of the digested sludge desorbed liquid and the carbon concentration of the concentrated dehydrated separated liquid of the primary settled sludge,
A control step of controlling the supply amount of the concentrated dewatered separation liquid of the first settled sludge so that the carbon concentration / the nitrogen concentration is a value within a predetermined range;
It is characterized by having.

  The digested sludge desorbing liquid treatment method according to the second invention is preferably the digested sludge desorbing liquid treatment method according to the first invention, wherein the carbon concentration is a BOD equivalent value.

  The digested sludge desorbing liquid treatment method according to the third invention is the digested sludge desorbing solution treating method according to the second invention, wherein the nitrogen concentration is a TN converted value, and the carbon concentration / nitrogen. The concentration is preferably more than 0.3 and less than 3.

  Moreover, the processing method of the digested sludge detachment liquid according to the fourth invention is the digested sludge detachment liquid processing method according to any one of the first to third inventions, wherein the treatment tank is a batch type. Is preferred.

  Moreover, the wastewater treatment method according to the fifth aspect of the present invention is a digestion sludge desorption according to any one of the first to fourth aspects of the invention in a biological reaction tank of a continuous biological treatment apparatus that biologically treats wastewater that flows continuously. It has the process water return process which returns the process water in the said processing tank obtained by the processing method of a liquid separation.

The digested sludge desorbing liquid treatment apparatus according to the sixth invention is
A treatment tank containing aerobic granules;
A supply path for supplying the treatment tank with digested sludge desorbed liquid and concentrated dehydrated separated liquid of primary settled sludge;
Concentration measuring means for measuring the nitrogen concentration of the digested sludge desorption liquid and the carbon concentration of the concentrated dehydrated separation liquid of the primary settled sludge, respectively.
Control means for controlling the supply amount of the concentrated dewatered separation liquid of the first settled sludge so that the carbon concentration / the nitrogen concentration falls within a predetermined range;
It is characterized by having.

The waste water treatment apparatus according to the seventh invention is
A continuous biological treatment apparatus equipped with a biological reaction tank for biological treatment of wastewater that flows continuously;
A digested sludge detachment liquid treatment apparatus according to the sixth invention;
A return path for returning treated water in the treatment tank of the treatment apparatus to the biological reaction tank;
It is characterized by having.

  With the above configuration, using aerobic granules, digested sludge desorbed liquid can be treated stably (nitrification and denitrification) for a long period of time. A wastewater treatment apparatus can be provided.

It is a block diagram which shows one Embodiment of the structure of the waste water treatment apparatus for enforcing the waste water treatment method of this invention. It is explanatory drawing for demonstrating the operating method of the processing apparatus of the digested sludge desorption liquid for enforcing the processing method of the digested sludge desorption liquid of this invention.

  In any way, the present inventor can use aerobic granules (granular aerobic microbial sludge) to remove digested sludge from the digested sludge desorbed liquid for a long period of time (nitrification and denitrification). We conducted intensive research on whether we could provide a liquid separation treatment method, a treatment apparatus therefor, a wastewater treatment method, and a wastewater treatment apparatus. As a result, it has been found that the object can be achieved only by adopting the configuration described below.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The organic wastewater to be treated by the present invention is, for example, sewage wastewater, wastewater from a food factory, and the like.

  (Configuration of waste water treatment equipment and digested sludge desorption liquid treatment equipment)

  1 and 2, 1 is an initial settling tank, 2 is a biological reaction tank, 3 is a final settling tank, 4 is, for example, a belt-type concentrator as a mechanical concentrating means, 5 is, for example, a pressurized flotation tank as a concentrator, 6 is a digestion tank, 7 is a dehydrator, 8 is a treatment tank containing aerobic granules (referred to as “aerobic granule treatment tank”), 11 is an inflow channel for drainage such as sewage containing various organic substances, 12 13, 15, 16, 17, 19, 20, 21, 24, 26, 33 are supply paths, 14 is an outflow path, 23 is a supply pipe, 25 is an outflow pipe, 18 and 22 are TOC (Total Organic Carbon, all (Organic carbon) meter, 27 is an ammonia meter, 30 is a control means, 31 is a signal path, and 32 is a valve. Reference numeral 40 denotes an aerobic granule treatment tank 8, a supply path 17, a TOC meter 18, a supply path 21, a TOC meter 22, a supply path 26, an ammonia meter 27, a control means 30, a signal path 31 and a valve 32. This is a processing apparatus for liquid separation.

  Next, the operation | movement operation | movement of the waste water treatment apparatus which concerns on this invention, and the processing apparatus of digested sludge desorption liquid is demonstrated, referring FIG. 1 and FIG.

  In FIG. 1, waste water is first supplied to the settling tank 1 from an inflow channel 11. The supplied waste water is firstly subjected to solid-liquid separation in the settling tank 1 to become primary settled sludge and separated liquid, respectively.

  The separation liquid is sent from the supply path 12 to the biological reaction tank 2, and air is blown into the separation liquid, and an aerobic biological treatment using activated sludge that converts organic substances in the separation liquid into carbon dioxide is performed. Treated water is supplied from the supply path 13 to the final settling tank 3. The supplied treated water is subjected to solid-liquid separation in the final sedimentation tank 3 to become excess sludge and treated water, respectively. This purified treated water is discharged from the outflow passage 14. A part of the sludge settled in the final sedimentation tank 3 is returned to the biological reaction tank 2 (not shown).

  On the other hand, the first settled sludge supplied to the belt-type concentrator 4 from the supply path 15 is concentrated and dehydrated to obtain concentrated raw sludge and concentrated dehydrated separation liquid. The concentrated dehydrated separation liquid is supplied from the supply path 17 to the aerobic granule. It supplies to the processing tank 8 (supply process). In addition, the carbon concentration of the concentrated dehydrated separation liquid supplied from the supply path 17 to the aerobic granule treatment tank 8 is measured by the TOC meter 18 (concentration measurement step).

  Further, the surplus sludge supplied from the supply path 19 to the pressurized flotation tank 5 is concentrated to obtain concentrated surplus sludge and a separated liquid, and this separated liquid is supplied from the supply path 21 to the aerobic granule treatment tank 8. (Supply process). Note that the carbon concentration of the separation liquid supplied from the supply path 21 to the aerobic granule treatment tank 8 is measured by the TOC meter 22 (concentration measurement step).

  Further, as the amount of the initial settled sludge drawn out from the supply path 15 to the belt-type concentrator 4 increases, the excess sludge supplied from the supply path 19 to the pressurized flotation tank 5 relatively decreases. Therefore, the amount of solid matter and organic matter in the concentrated surplus sludge supplied from the supply channel 20 to the digestion tank 6 is also relatively decreased by the amount of solid matter and organic matter in the concentrated raw sludge. Therefore, compared with the carbon source in the concentrated dehydrated separation liquid supplied from the supply path 17 to the aerobic granule treatment tank 8, the carbon source in the separation liquid supplied from the supply path 21 to the aerobic granule treatment tank 8. Will also decrease relatively.

  In particular, the amount of organic matter that moves to the digester 6 side via the belt-type concentrator 4 increases (that is, the amount of organic matter in the concentrated raw sludge supplied from the supply path 16 to the digester 6 increases). Means that the amount of organic substances in the separated liquid first separated in the precipitation tank 1 is reduced, and the amount of organic substances transferred to the biological reaction tank 2 side is reduced. Therefore, it becomes possible to realize a wastewater treatment method and wastewater wastewater treatment equipment that can reduce the amount of air blown when the biological reaction tank 2 is treated using the activated sludge method. In addition, since the amount of organic matter that must be processed in the biological reaction tank 2 is reduced, the amount of necessary air blown is reduced, and the power consumption in this step is also reduced (for example, the power cost of the blower can be reduced). . Furthermore, since the amount of organic matter that must be processed in the biological reaction tank 2 is reduced, the amount of surplus sludge supplied from the final sedimentation tank 3 via the supply path 19 is also reduced.

  The concentrated raw sludge supplied from the supply path 16 and the concentrated excess sludge supplied from the supply path 20 are each digested in the digestion tank 6 under anaerobic conditions, and converted into digestion gas mainly composed of methane gas. At the same time, digested sludge is obtained. Digestion gas is supplied through the supply pipe 23, and digested sludge is supplied from the supply path 24 to the dehydrator 7. As described above, the amount of organic matter converted into carbon dioxide or the like in the biological reaction tank 2 decreases, and the amount of easily decomposed organic matter that moves to the digester tank 6 side through the belt type concentrator 4 increases. It shows that digestion gas (for example, methane gas as a main component) that is useful as a fuel for heating of the digestion tank 6 or a gas engine for power generation can be generated with high efficiency in the digestion tank 6.

  Next, the digested sludge sent from the supply path 24 to the dewatering device 7 is solid-liquid separated by the dewatering device 7 to become a dehydrated cake and a digested sludge desorbed solution, respectively. The dehydrated cake flows out through the outflow pipe 25, and the digested sludge desorbed liquid is supplied from the supply path 26 to the aerobic granule treatment tank 8 (supply process). Note that the nitrogen concentration of the digested sludge desorbed liquid supplied from the supply path 26 to the aerobic granule treatment tank 8 is measured by the ammonia meter 27 (concentration measurement step).

  Further, from the control means 30 so that the total amount of the carbon concentration measured by the TOC meter 18 and the carbon concentration measured by the TOC meter 22 / the nitrogen concentration measured by the ammonia meter 27 falls within a predetermined range. Supplying the concentrated dewatered separation liquid of the first settled sludge supplied from the supply path 17 to the aerobic granule treatment tank 8 by adjusting the valve 32 with a control signal that is emitted and transmitted through the signal path 31 and reaches the valve 32 It is comprised so that quantity may be controlled (control process).

  For example, the carbon concentration measured by the TOC meter 18 and the TOC meter 22 is converted into BOD (biochemical oxygen demand), and the nitrogen concentration measured by the ammonia meter 27 is TN (Total Nitrogen, total nitrogen). Converted. What is necessary is just to control so that the total amount of nitrogen concentration / nitrogen concentration calculated from the converted value becomes a value within a predetermined range (greater than 0.3 and less than 3). If it is 0.3 or less, denitrification of the digested sludge effluent cannot be performed sufficiently due to a shortage of carbon source, and if it is 3 or more, not only the activity of nitrifying bacteria is reduced, but also bacteria other than aerobic granules are present. It tends to occur, the granule becomes unstable, and long-term operation becomes impossible. Considering these points, the carbon concentration / nitrogen concentration is more preferably 1.6.

  Next, the aerobic granule treatment tank 8 constituting the digested sludge desorbing liquid treatment apparatus 40 will be described in detail with reference to FIG. The aerobic granule treatment tank 8 is a batch type.

  FIG. 2A shows an aerobic granule 8b in which an air diffuser 8a is installed at the bottom of the aerobic granule treatment tank 8 and occupies about half the volume of the aerobic granule treatment tank 8. The process of filling is shown. In this state, the aerobic granule treatment tank 8 has about half the space.

  In FIG. 2B, in the approximately half space shown in FIG. 2A, the total amount of carbon concentration / nitrogen concentration is controlled so as to be a predetermined range value (greater than 0.3 and less than 3). A process of supplying the concentrated dehydrated separation liquid from the supply path 17, the separation liquid from the supply path 21, and the digested sludge desorption liquid from the supply path 26 to the liquid surface 8 c of the aerobic granule treatment tank 8 is shown.

  FIG.2 (c) shows the process of stirring and mixing by supplying air (oxygen) from the diffuser 8a for about 4 to 5 hours. 8d is a liquid level. In this situation, a nitrification reaction occurs near the surface of the aerobic granule 8b and a denitrification reaction occurs inside.

  FIG.2 (d) shows the process of stopping the stirring and mixing shown in FIG.2 (c), and precipitating sludge, such as aerobic granule 8b, by 5 m / h sedimentation separation. As described above, the digested sludge desorption liquid can be stably treated (nitrification and denitrification) for a long period of time using the aerobic granule 8b. In this treatment, the concentrated dehydrated separation liquid of primary settled sludge is mainly used as the carbon source, so that the amount of carbon source input from outside the system such as methanol can be reduced.

  In addition, as shown in FIG. 2 (d), sludge such as aerobic granules 8b is allowed to settle in the lower half of the aerobic granule treatment tank 8, and the digested sludge desorbed solution is treated (nitrification and The upper half of the denitrified treated water 8e is returned from the supply path 33 to the biological reaction tank 2 shown in FIG. 1 (treated water returning step). 8f is a liquid level.

  As described above, for the treatment (nitrification and denitrification) of the digested sludge desorbed liquid, the carbon source (carbon source derived from organic matter) in the concentrated dehydrated separated liquid of the primary settled sludge is consumed. The nitrogen source in the digested sludge desorption liquid is removed and the amount of carbon source in the treated water 8e returned to the biological reaction tank 2 is also reduced. Accordingly, since the amount of organic matter that must be treated in the biological reaction tank 2 is reduced, the wastewater treatment method and wastewater that can further reduce the amount of air blown when the biological reaction tank 2 is treated using the activated sludge method. A processing apparatus can be realized. Therefore, the power consumption in this step is further reduced (for example, the power cost of the blower can be further reduced).

  In this embodiment, in addition to supplying the digested sludge detachment liquid and the concentrated dewatered separation liquid of the first settled sludge to the aerobic granule treatment tank 8, the supply path for the separation liquid obtained by concentrating excess sludge Although the example which supplies to the aerobic granule processing tank 8 from 21 was demonstrated, it is not necessarily limited to this. At least the digested sludge detachment liquid and the concentrated dehydrated separation liquid of the first settled sludge may be supplied to the aerobic granule treatment tank 8.

  Further, in the present embodiment, the concentrated dehydrated separation liquid supplied from the supply path 17 to the aerobic granule treatment tank 8 and the separation liquid supplied from the supply path 21 to the aerobic granule treatment tank 8 each have a carbon concentration. Although an example in which only measurement is performed has been described, the present invention is not necessarily limited thereto. For example, a configuration that measures the nitrogen concentration in addition to the carbon concentration is more preferable.

  Moreover, in this embodiment, although the digested sludge desorption liquid supplied to the aerobic granule processing tank 8 from the supply path 26 demonstrated the example in which only nitrogen concentration was measured, it is not necessarily limited to this. is not. For example, a configuration that measures the carbon concentration in addition to the nitrogen concentration is more preferable.

  This is because the carbon concentration and nitrogen concentration of the concentrated dehydrated separation liquid, the separation liquid, and the digested sludge desorption liquid are measured, and the total carbon concentration / total nitrogen concentration is within a predetermined range (over 0.3 and above 3 If the aerobic granules 8b are used, the digested sludge desorbed liquid can be stably treated for a long time and more efficiently treated (nitrification and denitrification).

  In this embodiment, the example in which the valve 32 is provided only in the supply path 17 and the supply amount of the concentrated dehydrated separation liquid of the initial settled sludge is controlled by the control means 30 has been described, but the present invention is not necessarily limited thereto. It is not a thing. For example, the supply passages 21 and 26 are also provided with valves, respectively, so that the separation liquid supplied from the supply passage 21 and the supply passage 26 are controlled by the control means 30 so that the total amount of carbon concentration / nitrogen concentration becomes a value within a predetermined range. You may control each supply amount of the digested sludge desorption liquid supplied from.

  The embodiment of the present invention has been described above, but only specific examples are illustrated, and the present invention is not particularly limited, and the specific configuration and the like can be appropriately changed in design. In addition, the actions and effects described in the embodiments of the present invention only list the most preferable actions and effects resulting from the present invention, and the actions and effects according to the present invention are described in the embodiments of the present invention. It is not limited to things.

DESCRIPTION OF SYMBOLS 1 First settling tank 2 Biological reaction tank 3 Final settling tank 4 Belt type concentrator 5 Pressurized floating tank 6 Digestion tank 7 Dehydration apparatus 8 Aerobic granule processing tank 8a Aeration apparatus 8b Aerobic granules 8c, 8d, 8f Surface 8e Treated water 11 Inflow path 12, 13, 15, 16, 17, 19, 20, 21, 24, 26, 33 Supply path 14 Outflow path 23 Supply pipe 25 Outflow pipe 18, 22 TOC meter 27 Ammonia meter 30 Control means 31 Signal path 32 Valve 40 Digested sludge desorption liquid processing equipment

Claims (7)

A supply step of supplying a digested sludge desorption liquid and a concentrated dewatered separation liquid of primary settled sludge to a treatment tank containing aerobic granules;
A concentration measuring step for measuring the nitrogen concentration of the digested sludge desorbed liquid and the carbon concentration of the concentrated dehydrated separated liquid of the primary settled sludge,
A control step of controlling the supply amount of the concentrated dewatered separation liquid of the first settled sludge so that the carbon concentration / the nitrogen concentration is a value within a predetermined range;
A method for treating digested sludge desorbed liquid, comprising:   The method for treating a digested sludge desorption liquid according to claim 1, wherein the carbon concentration is a BOD equivalent value.   The method for treating a digested sludge desorbing solution according to claim 2, wherein the nitrogen concentration is a TN converted value, and the carbon concentration / the nitrogen concentration is more than 0.3 and less than 3.   The said processing tank is a batch type, The processing method of the digested sludge desorption liquid of any one of Claims 1-3 characterized by the above-mentioned.   In the biological reaction tank of the continuous type biological treatment apparatus which biologically processes the waste water which flows in continuously, in the said processing tank obtained by the processing method of the digested sludge desorption liquid of any one of Claims 1-4 A wastewater treatment method comprising a treated water return step for returning treated water. A treatment tank containing aerobic granules;
A supply path for supplying the treatment tank with digested sludge desorbed liquid and concentrated dehydrated separated liquid of primary settled sludge;
Concentration measuring means for measuring the nitrogen concentration of the digested sludge desorption liquid and the carbon concentration of the concentrated dehydrated separation liquid of the primary settled sludge, respectively.
Control means for controlling the supply amount of the concentrated dewatered separation liquid of the first settled sludge so that the carbon concentration / the nitrogen concentration falls within a predetermined range;
An apparatus for treating digested sludge detachment liquid, comprising: A continuous biological treatment apparatus equipped with a biological reaction tank for biological treatment of wastewater that flows continuously;
A processing apparatus for digested sludge desorption liquid according to claim 6,
A return path for returning treated water in the treatment tank of the treatment apparatus to the biological reaction tank;
A wastewater treatment apparatus characterized by comprising:

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