JP6052849B2 - Water treatment equipment - Google Patents

Description

  The present invention relates to a water treatment apparatus having a filling region filled with a contact material.

  Japanese Patent Application Laid-Open No. 2002-239570 discloses a water treatment apparatus for treating inflow wastewater. In this water treatment apparatus, a contact material is filled in a biofilm treatment tank, and a desired aerobic treatment is performed through a biofilm attached to the filled contact material.

JP 2002-239570 A

  In a water treatment apparatus having a filling region filled with the contact material as described above, the retention performance of the biofilm in the filling material may be reduced due to factors such as treatment conditions and usage environment of the water treatment apparatus. Concerned. Specifically, at the initial use start time of the contact material, the period required for the biofilm to sufficiently adhere to the contact material becomes longer (the start of biofilm adhesion at the start of operation becomes slower) Alternatively, at the time when the temperature of the water to be treated rises or falls significantly, a phenomenon that the biofilm already attached to the contact material peels off may occur. Therefore, when designing this type of water treatment apparatus, it is required to improve the biofilm retention of the contact material. On the other hand, as a contact material used for a water treatment apparatus, the versatility of the contact material in a net-like form is high.

  Therefore, the present invention has been made in view of the above problems, and in a water treatment apparatus provided with a filling region filled with a net-like contact material, to improve the biofilm retention of the contact material. The objective is to provide effective technology.

  In order to solve the above problems, the present invention according to the claims is configured.

The water treatment apparatus according to the present invention includes a treatment tank body, a water treatment unit, a contact material filling region, and a biofilm holding mechanism. The treatment tank main body has a housing space, and a water treatment unit for treating the water to be treated is provided in the housing space. The contact material filling region is configured as a region filled with a plurality of contact materials in the water treatment unit. The biofilm holding mechanism is configured as a mechanism for enhancing the biofilm holding property of the contact material. The contact material is a net-like roll body formed by extrusion molding of a thermoplastic resin containing a foam material . The contact material filling region is configured as an aerobic treatment region that performs aerobic treatment of water to be treated by aeration of the contact material in the water treatment unit, and the contact material is prevented from flowing of the contact material. The aerobic treatment area is filled in an immobilized state. Thereby, it becomes possible to improve the biofilm retention of the net-like contact material by the biofilm retention mechanism. In addition, the “biofilm retention” herein refers to the performance as the ease of attachment of the biofilm attached to the contact material, and the difficulty of peeling off the biofilm once attached to the contact material from the contact material. Performance is included. The “contact material” here includes various supports for generating and attaching a biofilm or having the possibility of generating and attaching a biofilm.

  In addition, the contact material filling region is configured as an aerobic treatment region that performs aerobic treatment of water to be treated in the water treatment unit, and the contact material is in an aerobic treatment region in a fixed state that prevents the flow of the contact material. Filled. Thereby, in the fixed contact material used for the aerobic treatment of the water to be treated, the biofilm retention of the contact material can be improved. In addition, the cost of the contact material itself and the cost of the fixing member from which the flowing contact material flows out can be reduced as compared with the fluid contact material (carrier). In addition, by filling in a fixed state, the amount of biofilm in the contact material is kept high to increase the water treatment performance, while the structure for preventing the contact material from flowing out can be simplified. is there. In the case of filling in a fixed state, since the contact material does not flow along the water flow caused by aeration during the aerobic treatment, the relative water flow speed on the surface of the contact material tends to increase. In this regard, in the conventional immobilization structure, the biofilm adhesion rate at the beginning of filling is hardly improved, and the biofilm is easily peeled off according to the environmental change. In other words, it is assumed that there is a problem that the processing performance is likely to vary as compared with the fluid contact material. In this aspect, the aspect in which the biofilm retention property according to the present invention can be set high, the point at which the biofilm adhesion rate can be increased, or the point at which peeling of the biofilm is suppressed is filled with the contact material in the immobilized state. By using appropriately, the above conventional problems can be effectively solved.

Furthermore, in the water treatment apparatus according to the invention, a plurality of contact materials are filled in the aerobic treatment region so that the respective cylinder shafts are irregularly directed to each other . This makes it possible to substantially maximize the distribution contact area of the treated water with respect to the biofilm formed on the contact material .

Furthermore, in the water treatment apparatus according to the present invention, the biofilm holding mechanism is a contact set such that the surface roughness (Ra) of the contact material exceeds 20 [μm] due to foaming of the foamed material during extrusion molding. It is preferably configured as a concavo-convex structure on the material surface. Thereby, the structure which a contact material has predetermined | prescribed surface roughness is simply realizable by resin molding.

This is also effective in improving biofilm retention by increasing the surface roughness of the contact material surface and increasing the surface area.

Furthermore, in the water treatment apparatus according to the present invention, the biofilm holding mechanism includes a biofilm detachment suppressing unit due to the uneven structure of the contact material . This biofilm detachment suppression unit suppresses the biofilm attached to the contact material, that is, the biofilm already attached to the contact material, from being peeled off at the time when the temperature of the water to be treated in the contact material filling region is increased. It fulfills the function of enhancing biofilm retention. According to this configuration, the biofilm retainability of the contact material is improved by making it difficult to peel the biofilm once attached to the contact material from the contact material, particularly at the time when the temperature of the water to be treated in the contact material filling region increases. It is effective.

  In a further form of the water treatment apparatus according to the present invention, the biofilm holding mechanism preferably includes a biofilm adhesion rate setting unit. The biofilm adhesion rate setting unit functions to increase the deposition rate of the biofilm that adheres to the contact material at the start of use of the contact material, thereby increasing the biofilm retention. According to this configuration, particularly when the contact material starts to be used, it is effective to enhance the biofilm retention of the contact material by facilitating adhesion of the biofilm to the contact material.

  As described above, according to the present invention, it is possible to improve the biofilm retainability of the contact material in the water treatment apparatus including the filling region filled with the net-like contact material.

It is a figure which shows the processing flow of the water treatment apparatus 100 concerning this invention. It is a figure which shows the outline | summary of a structure of the aerobic filter floor tank 150, the treated water tank 170, and the disinfection tank 190 among the several water treatment elements of the water treatment apparatus 100 in FIG. It is a perspective view of the filter medium C3 with which the contact aeration part 151 of the aerobic filter bed tank 150 in FIG. 2 was filled. The contact materials of Examples and Comparative Examples, illustrates the passage of days changes in ammonium nitrogen concentration in the water from the start operation (NH ₄ -N) (data B). The contact materials of Examples and Comparative Examples, illustrates passage of days changes in ammonium nitrogen concentration in the water in the water temperature rise timing (NH ₄ -N) (data D). The contact materials of Examples and Comparative Examples is a diagram showing a temporal change of the ammonia nitrogen concentration (NH ₄ -N) in May 28 a water temperature rise time. The contact materials of Examples and Comparative Examples is a diagram showing a temporal change of the ammonia nitrogen concentration (NH ₄ -N) in July 26 stable time after the water temperature rise time. It is a figure which shows the aspect of the water temperature rise in each Example.

  Below, the structure of the water treatment apparatus of one Embodiment in this invention is demonstrated based on drawing. Note that this embodiment describes a water treatment apparatus that receives and treats raw water (also referred to as “drainage” or “treated water”) discharged from ordinary households, apartment houses, etc., into a water treatment area. .

  A schematic flow of the water treatment apparatus 100 according to the present invention is shown in FIG. As shown in FIG. 1, the water treatment apparatus 100 of the present embodiment has a treatment tank body 101 as a casing of the water treatment apparatus 100. The water treatment apparatus 100 is a water treatment apparatus that treats domestic wastewater (living sewage) together with manure, and is also referred to as a “septic tank” or a “merged treatment septic tank”.

  The processing tank main body 101 is typically configured in a tank shape by abutting an upper tank and a lower tank, both of which are formed in a half-crack shape, and the processing tank main body 101 has a hollow accommodating space 101a. Is formed. The accommodation space 101a is provided with a water treatment unit 101b (also referred to as “water treatment mechanism”) described later. The treatment tank main body 101, the accommodation space 101a, and the water treatment part 101b here correspond to the “treatment tank main body”, “accommodation space”, and “water treatment part” in the present invention, respectively.

  The processing tank main body 101 includes an inflow pipe 102, an outflow pipe 103, and a manhole portion 104. The inflow pipe 102 is configured as an opening for introducing raw water before treatment into the internal space of the treatment tank main body 101. The outflow pipe 103 is configured as an opening for the treated water to be led out from the internal space of the treatment tank main body 101. The manhole portion 104 is configured as a portion where manholes for tank entry, internal inspection, and cleaning are formed.

  In addition, in this specification, among the treatment tank main body 101 and each water treatment element, the manhole part 104 side is prescribed | regulated as a tank upper part or a tank upper part, and the other side is prescribed | regulated as a tank lower part, a tank lower part, or a tank bottom part. Further, the inflow pipe 102 side of the processing tank body 101 is defined as the upstream side, and the outflow pipe 103 side is defined as the downstream side. In addition, a direction (typically, a direction orthogonal) intersecting the horizontal direction along the extending surface of the manhole portion 104 is defined as a vertical direction (also referred to as “tank vertical direction”).

  The water treatment unit 101b includes a precipitation separation tank 110, an anaerobic filter bed tank 130, an aerobic filter bed tank 150, a treated water tank 170, and a disinfection tank 190 as its water treatment elements. In this water treatment unit 101b, the water to be treated that has flowed into the treatment tank main body 101 through the inflow pipe 102 is first treated in the precipitation separation tank 110, and then the anaerobic filter bed tank 130 and the aerobic filter bed tank 150. Then, it is sequentially buried in the treatment water tank 170 and the disinfection tank 190 and finally flows out of the treatment tank body 101 through the outflow pipe 103. In this case, the water treatment apparatus 100 may be configured as a septic tank configured to discharge the water that has flowed out of the treatment tank body 101 as it is, or the water that has flowed out of the treatment tank body 101 may be used as a toilet. Alternatively, it may be configured as a water reuse device that is reused as water for watering.

  The sedimentation separation tank 110 includes a peak cut unit 111, a sludge storage unit 112, and a sedimentation separation unit 113. The peak cut portion 111 is a space in the upper portion of the sedimentation separation tank 110 (above the sludge storage portion 112 and the sedimentation separation portion 113), and is configured as a portion where the water level fluctuates according to the amount of inflow water. Thereby, the water level fluctuation | variation when the inflow water amount increases is absorbed by the peak cut part 111. FIG. The sedimentation separation unit 113 serves as a mechanism for separating sludge (solid matter) contained in the inflow water from the inflow pipe 102. The sedimentation separation unit 113 typically has a multi-sided hopper-shaped partition wall, and the partition region partitioned by the partition wall is configured so that the cross-sectional area along the water surface decreases as it goes to the bottom of the tank. ing. Therefore, the sludge in the inflowing water is separated and collected by the settling and separation action in the compartment area. The sludge separated by the sedimentation separation unit 113 is transferred to the sludge storage unit 112 via a sludge circulation pump 114 as an air lift type transfer pump.

  On the other hand, the water after the sludge is separated by the precipitation separation unit 113 flows out to the anaerobic filter bed tank 130. The sludge storage unit 112 communicates with the sedimentation separation unit 113 and serves as a mechanism for storing the sludge after separation. The sludge storage section 112 is provided with a filling region for a loofah-like filter material C1 in which a net-like or linear resin is irregularly meshed as a typical filter material. A diffuser pipe (not shown) for performing aeration agitation at all times is installed below. The filling region is filled with a plurality of filter media C1 in an immobilized state in which the flow of the filter media is prevented.

  The anaerobic filter bed tank 130 includes a peak cut portion 131 and an anaerobic filter bed 132. The peak cut part 131 is a space in the upper part of the anaerobic filter bed tank 130 (above the anaerobic filter bed 132), and is configured as a part where the water level fluctuates according to the amount of inflow water, similar to the peak cut part 111 described above. ing. The anaerobic filter bed 132 has a function of anaerobically treating (reducing) organic pollutants contained in the tank water and a function of filtering water. In addition, denitrification treatment is performed to reduce nitrate nitrogen contained in the circulating water described later to nitrogen gas. For this purpose, the anaerobic filter bed 132 is filled with a plurality of anaerobic filter media C2 to which anaerobic microorganisms for anaerobically treating organic pollutants are attached in a fixed state in which the flow of the filter media is prevented. This anaerobic filter medium C2 is typically configured as a mesh-like cylindrical filter medium. When the water in the tank flows downward through the anaerobic filter bed 132 (anaerobic filter medium C2), anaerobic sludge (solid matter) is trapped by the filtration treatment and BOD is removed.

  The anaerobic sludge separated by the anaerobic filter bed 132 and deposited on the bottom of the tank is transferred to the sludge separation section 113 of the precipitation separation tank 110 via an anaerobic sludge transfer pump 133 as an air lift type transfer pump. Thereby, the anaerobic sludge separation process is performed in the sedimentation separation unit 113. As a result, since the sludge separation process is repeatedly performed between the sediment separation unit 113 and the anaerobic filter bed 132, the sludge separation effect can be enhanced. The anaerobic sludge transfer pump 133 is preferably configured to operate in conjunction with a backwash pump 153 used during a backwash operation of the biological filtration unit 152 of the aerobic filter bed 150 described later.

  On the other hand, the water after the anaerobic sludge is separated by the anaerobic filter bed 132 is transferred to the aerobic filter bed tank 150 via the peak cut transfer pump 134 as an air lift type transfer pump, and the anaerobic filter bed tank 130. A return weir is provided in a partition wall that divides the aerobic filter floor tank 150. By adjusting the amount of water returning from the aerobic filter bed tank 150 to the anaerobic filter bed tank 130 through the return weir, the amount of water transferred from the anaerobic filter bed tank 130 to the aerobic filter bed tank 150 is adjusted. Along with this, the water level of the anaerobic filter bed tank 130 fluctuates similarly to the precipitation separation tank 110.

  As shown in FIG. 2, the aerobic filter bed tank 150 includes a contact aeration unit 151 and a biological filtration unit 152. In addition, the contact aeration unit 151 and the biological filtration unit 152 are juxtaposed with each other and communicated at the tank upper part (near the water surface) and the tank bottom. That is, the contact aeration unit 151 and the biological filtration unit 152 communicate with each other through an opening 155 formed in the upper part of the partition wall at the top of the tank and through an opening 156 formed in the lower part of the partition wall at the tank bottom. doing. The contact aeration unit 151 is filled with a plurality of mesh-like or loofer-like filter media C3 as a typical filter medium in a fixed state in which the flow of the filter medium is blocked, and the bottom of the tank is filled with the filter medium C3. The entire surface is aerated from the provided air diffuser 154 so that the water in the tank flows upward. The contact aeration unit 151 here is an aerobic treatment region for performing aerobic treatment of water to be treated, and is a filling region for the filter medium C3. In the present invention, the “contact material filling region” and the “aerobic treatment region” are used. Is equivalent to. On the other hand, the biological filtration unit 152 is filled with a plurality of hollow cylindrical carriers C4 in an immobilized state in which the carriers are prevented from flowing.

  According to the above configuration, due to the water flow by aeration in the contact aeration unit 151, in the contact aeration unit 151, an upward water flow is formed from the bottom of the tank through the filling region of the filter medium C3 to the upper part of the tank. In the biological filtration unit 152, a downward water flow is formed from the upper part of the tank through the filling region of the carrier C4 to the bottom of the tank. As a result, a circulating flow is formed between the contact aeration unit 151 and the biological filtration unit 152, BOD removal and nitrification reaction are performed in the contact aeration unit 151, and SS is captured in the biological filtration unit 152. . The tank bottom of the biological filtration unit 152 communicates with the tank bottom of the treated water tank 170 through an opening 157 formed in the lower part of the partition wall, and the water of the biological filtration unit 152 is configured to transfer to the treated water tank 170. ing.

  In this embodiment, in order to prevent the carrier C4 from being blocked, a backwash pipe is provided below the biological filtration section 152, and a periodic air supply from the backwash pipe during the backwash operation. Is performed, the water in the biological filtration unit 152 is stirred and mixed, and the sludge is separated from the carrier C4 by this stirring and mixing. The water containing the separated sludge is pumped up from above the biological filtration unit 152 by a backwash pump 153 as an airlift type transfer pump, and is circulated and transferred to the precipitation separation unit 113 of the precipitation separation tank 110. In 113, sludge separation processing is performed.

  In the treated water tank 170, water flowing in from the bottom of the tank is temporarily stored while flowing upward in the treated water tank 170. Thereafter, the water in the treatment water tank 170 is transferred to the disinfection tank 190 through the advection weir 172 provided on the partition wall that partitions the treatment water tank 170 and the disinfection tank 190. At this time, based on the weir height of the advection weir 172, the peak cut transfer water amount from the anaerobic filter bed tank 130 is adjusted. The water at the bottom of the treatment water tank 170 is pumped up by a circulation pump 171 as an airlift type transfer pump and is circulated to the precipitation separation tank 110.

  The disinfection tank 190 includes a medicine cylinder 191 filled with a solid disinfectant for performing disinfection processing. The water in the sterilization tank 190 is sterilized by the disinfectant eluted from the medicine cylinder 191, and the water after the sterilization process is discharged out of the processing tank body 101 through the outflow pipe 103. In connection with this configuration, another tank, such as a discharge pump tank in which a discharge pump is installed, may be provided downstream of the disinfection tank 190.

  By the way, in the water treatment apparatus 100 of the said structure, since it installs outdoors and is used continuously throughout the year, the case where water treatment conditions, use environment, etc. fluctuate is assumed. And there is a concern that the biofilm retainability of the filter medium C3 filled in the contact aeration unit 151 of the aerobic filter bed tank 150 may decrease due to such a variation factor. Specifically, the problem that the period required for the biofilm to sufficiently adhere to the filter medium C3 from the start of use of the filter medium C3 becomes long (the start of biofilm adhesion at the start of operation becomes slow), or within one year At the time when the water temperature rises or falls significantly, there may be a problem that the biofilm already attached to the filter medium C3 is peeled off. In short, “biofilm retention” as used herein refers to the performance of the biofilm that adheres to the contact material in the initial stage of use, or the separation of the biofilm once attached to the contact material from the contact material. The performance as difficulty is included. Therefore, when designing this type of water treatment apparatus, it is required to prevent a decrease in the biofilm retention of a contact material such as the filter medium C3 due to variable factors such as water treatment conditions and use environment.

  As a result of intensive studies in view of the above-mentioned problems, the present inventors have improved biofilm retention as compared with conventional products as a contact material that can be applied as the filter medium C3 filled in the contact aeration unit 151 of the present embodiment. We have succeeded in developing a contact material C3 with improved resistance. This contact material C3 is formed into a net-like roll shape by extrusion molding of a thermoplastic resin, and as a whole, a cylindrical shape (outer diameter: D1, inner diameter: D2, cylindrical height: H as shown in FIG. 3). The cylinder axis: A), and in particular, the surface thereof has a predetermined surface roughness (also referred to as “surface roughness”). The contact material C3 here corresponds to the “contact material” in the present invention.

  The contact material C3 having the above-described configuration includes a dense portion (cylinder wall portion) that is a region having a relatively low porosity and an air-spaced portion (in-cylinder space) that is a region having a relatively high porosity. The air sparse part fulfills the function of securing the flow path of the water to be treated, while fulfilling the function of mainly holding the biofilm. Therefore, when a plurality of contact materials C3 are filled, the plurality of contact materials are preferably filled in an immobilized state in which flow is prevented. As a result, the biofilm retention of the contact material can be improved, and the cost of the contact material itself and the fixing member from which the flowing contact material flows out can be compared to the fluid contact material (carrier). Cost can be kept low. Further, it is preferable that the cylinder shafts A of the plurality of contact materials are regularly filled so as to be directed in the same direction. Thereby, especially in the net-like roll-shaped contact material C3, since the to-be-processed water can distribute | circulate the inside of a cylinder along the cylinder axis A, it is effective in improving the contact efficiency with to-be-processed water.

<Surface roughness>
The inventors of the present invention have surface roughness (hereinafter also referred to as “contact material of a comparative example”) and contact roughness C3 (hereinafter also referred to as “contact material of an example”) of the present embodiment. Ra) was measured using a stylus type surface roughness measuring machine based on the standard of JISB0601: 2001, respectively. The surface roughness (Ra) mentioned here corresponds to the “surface roughness” in the present invention. As a result, the surface roughness of the contact material of the comparative example is 6.4 (average value) ± 3.3 (standard deviation) [μm], whereas the surface roughness of the contact material of the example is It was 56.6 (average value) ± 14.2 (standard deviation) [μm]. All of these measured values are the results of measuring three samples with the measurement length of the sample and the off-cut wavelength set to 8 [mm]. When based on said measurement result, it was confirmed that the contact material of a comparative example has a smooth surface, a low degree of unevenness | corrugation, and a small surface area compared with the contact material of an Example. In addition, the surface roughness of the contact material of the example is the unevenness formed on the surface of the contact material by foaming of the foam material at the time of resin molding for the contact material formed by extrusion molding of the thermoplastic resin containing the foam material. It is preferably constituted by a structure. Therefore, the concavo-convex structure on the surface of the contact material here constitutes the “biofilm holding mechanism”, “biofilm adhesion rate setting unit”, and “biofilm detachment suppressing unit” of the present invention. Typically, the amount of foaming material added to the thermoplastic resin, foaming conditions, and the like can be appropriately set based on the surface roughness of the resulting contact material. Thereby, the structure which a contact material has predetermined | prescribed surface roughness is simply realizable by resin formation.

  Here, the water treatment performance when the contact materials of the above-described examples and comparative examples are actually used will be described. The water treatment performance includes, for example, the start-up performance of the contact material at the start of operation (hereinafter also referred to as “first water treatment performance”) and the biofilm retention performance of the contact material (hereinafter referred to as “second water treatment performance”). It is also divided into

<First water treatment performance>
In the present embodiment, the biofilm adhesion amount (data A) attached to the contact material at the start of operation and the daily change (data B) of the ammonia nitrogen concentration (NH ₄ -N) in the water from the start of operation. Based on this, the first water treatment performance was evaluated.

  Regarding data A, a first treatment tank (capacity: 50 L) assuming an anaerobic filter bed tank 130, a second treatment tank (capacity: 20 L) assuming an aerobic filter bed tank 150, and a third treating water tank 170 are assumed. Two experimental tanks (total capacity: 90 L) comprising treatment tanks (capacity: 20 L) were prepared. One experimental tank was used for the example and the other experimental tank was used for the comparative example. In the experimental tank for the examples, a contact material C having a cylindrical shape (outer diameter: 100 [mm], inner diameter: 65 [mm], length: 100 [mm], average wire diameter: 1.5 [mm]) is used. Twelve in the second treatment tank were filled and aeration of 14 [L / min] was performed. On the other hand, in the experimental tank for the comparative example, 12 conventional contact materials having the same dimensions as the contact material C were filled in the second treatment tank, and aeration of 14 [L / min] was performed. And the actual domestic waste water was made to flow into the 1st processing tank of each experimental tank at the supply rate of 50L / day, and a part of water of the 3rd processing tank was circulated to the 1st processing tank. The biofilm adhesion state of the contact material visually in this case was taken as data A. According to this data A, it was confirmed that the amount of biofilm deposited on the contact material of the example was clearly larger than that of the comparative example until the 20th day. Therefore, based on the data A, it can be evaluated that the contact material of the example has a higher biofilm adhesion rate at the start of operation than the contact material of the comparative example, and the start-up performance at the start of operation is excellent. .

  For data B, the daily change in ammonia nitrogen concentration in water when the same treatment was performed in the same experimental tank as in data A was shown in data B (Example: ○ plot, Comparative example: ■ plot) It was. As can be seen from FIG. 4, according to this data B, the ammonia nitrogen concentration on the 20th day from the start of the operation was almost zero in the case of the contact material of the example, In the case of the contact material of the comparative example, the concentration was about 10 [mg / L]. This is due to the fact that the biofilm deposition rate at the start of operation in the example was higher than that in the comparative example, as in the data A described above. Therefore, based on the data B, it can be evaluated that the nitrification performance at the start of operation is faster in the example than the comparative example, and the start-up performance at the start of operation is superior.

<Second water treatment performance>
In the present embodiment, the biofilm adhesion amount (data C) adhering to the contact material at the time of water temperature rise, and the daily change (data D) of the ammonia nitrogen concentration (NH ₄ -N) in the water at the water temperature rise time The second water treatment performance was evaluated based on the nitrification rate (data E) and the amount of sludge (data F).

  Regarding data C, when the same treatment is performed in the same experimental tank as in data A, in May, which is the water temperature transition time when the water temperature will exceed 20 ° C., the biofilm of the visual contact material The adhesion state was designated as data C. This water temperature increase mode is shown in FIG. According to this data C, it was confirmed that the amount of biofilm deposited on the contact material of the example rapidly decreased as compared with the case of the contact material of the comparative example at the time when the water temperature rose. Therefore, based on the data C, the contact material of the example has a smaller amount of biofilm peeled from the contact material than the contact material of the comparative example, and the biofilm retention performance at the time when the water temperature rises (see FIG. 8). Can be evaluated as excellent.

  Regarding data D, data D (Example: ○ plot, comparative example) shows the daily change of ammonia nitrogen concentration in the water at the time of the water temperature rise when the same treatment is performed in the same experimental tank as in data C. : ■ plot). As shown in FIG. 5, according to the data D, the ammonia nitrogen concentration from mid-May to mid-June is about 1 [mg / L] in the case of the contact material of the example. In contrast, in the case of the contact material of the comparative example, the concentration was 5 [mg / L] or more. This is due to the fact that the amount of peeling of the biofilm from the contact material of the example was smaller than that of the comparative material as in the data B described above. Therefore, based on the data D, it can be evaluated that the contact material of the example is superior to the contact material of the comparative example in nitrification performance at the water temperature rise time (see FIG. 8).

Regarding data E, first, in the same experimental tank as in data C, NH ₄ Cl was added so that the ammonia nitrogen concentration in the tank was about 20 mg / L with the inflow and circulation stopped. The internal water was collected at regular intervals on May 28 and July 26, and the change over time in the ammonia nitrogen concentration (NH ₄ -N) was derived. For the calculation result, the graph of FIG. 6 (May 28) and the graph of FIG. 7 (July 26) are referred to. The nitrification rate calculated from the slopes of the respective graphs in FIGS. 6 and 7 was defined as data E (Example: ○ plot, Comparative example: ■ plot). In this data E, the nitrification rate on May 28, which is the water temperature rise time, is 0.30 [kg-N / day] per 1 m ³ bulk capacity of the contact material in the case of the contact material of the example. It was about 1.7 times of 0.18 [kg-N / day] in the case of the contact material of the example. In contrast, the nitrification rate on July 26, which is the stable period after the water temperature rise period, is 0.29 [kg-N / day] per 1 m ³ of bulk capacity of the contact material in the case of the contact material of the example. There was almost no difference from 0.28 [kg-N / day] in the case of the contact material of the comparative example. Therefore, according to the data E, by using the contact material of the example, it is possible to prevent the deterioration of the nitrification rate at the time when the water temperature rises (see FIG. 8). It can be evaluated that the nitrification performance at the time of water temperature rise is superior to that of the contact material.

  Regarding data F, the amount of sludge (total amount of sludge) finally remaining in the tank when the same treatment was performed for about 300 days in the same experimental tank as in data C was used as data F. In this data F, the amount of sludge (dry weight) was 0.35 [kg] in the case of the contact material of the example with respect to 0.46 [kg] in the case of the contact material of the comparative example. Therefore, according to the data F, the amount of sludge generation can be suppressed by giving the contact material of the embodiment. This is because the contact material of the example increased the rate of sludge volume reduction due to an increase in biomass (total amount of organisms) due to an increase in bioadhesion, and it can be evaluated that the biofilm retention performance is excellent. .

  As described above, when based on the performance evaluation of the contact material of the example, at the time when the contact material starts to be used, by making it easier for the biofilm to adhere to the contact material, and when the temperature of the water to be treated is increased It was confirmed that the biofilm retainability of the contact material can be enhanced by making it difficult to peel the biofilm once attached to the contact material from the contact material. Based on this evaluation result, it is possible to improve the biofilm retention of the contact material in the water temperature decrease period (autumn) of the water to be treated as well as the water temperature increase period of the water to be processed shown in FIG. .

  In addition, when based on the value of the above-mentioned surface roughness, this Embodiment can be comprised so that the surface roughness of a contact material may exceed 20 [micrometers]. This is effective for improving the biofilm retention by increasing the surface roughness of the contact material surface and increasing the surface area. More preferably, it can be configured such that the surface roughness of the contact material is approximately 40 [μm] or more. Thereby, it becomes possible to further improve the biofilm retainability of the contact material.

[Other Embodiments]
In addition, this invention is not limited only to said embodiment, A various application and deformation | transformation can be considered. For example, each of the following embodiments to which the above embodiment is applied can be implemented.

  In the said embodiment, the contact material concerning this invention is applied with respect to the structure of the filter medium with which the contact aeration part 151 which is an aerobic treatment area | region is especially filled among the several water treatment elements of the water treatment apparatus 100. FIG. Although the case has been described, in the present invention, the contact material can also be applied to a configuration of a packing (filter medium, carrier, etc.) filled in a region different from the contact aeration unit 151. In the water treatment device 100 having the above-described configuration, for example, the contact material according to the present invention can be filled in place of the filter medium C1 filled in the sludge storage unit 112 and the carrier C4 filled in the biological filtration unit 152. Note that the contact material may be a net-like contact material that is net-like and configured to have a variable porosity in response to requests such as a filling region and processing conditions. A contact material configured so that the porosity is substantially uniform can be used. At this time, the shape of the contact material is a cylinder, a polygonal column, a circle, a triangle, a rectangle, an ellipse, a corrugated, a honeycomb. Various types of contact materials such as shapes can be selected. The material of the contact material is typically a resin material such as polyethylene resin or polypropylene resin.

  Further, in the above embodiment, the description has been given of the case where the uneven structure on the surface of the contact material set so that the contact material has a predetermined surface roughness is formed by foaming of the foam material at the time of resin molding. A predetermined uneven structure on the surface of the contact material may be formed by machining after resin molding or the like.

  Moreover, in the water treatment apparatus 100 of the said embodiment, the water treatment part 101b is comprised by each process element of the precipitation separation tank 110, the anaerobic filter bed tank 130, the aerobic filter bed tank 150, the treated water tank 170, and the disinfection tank 190. In the present invention, the number and types of treatment elements of the water treatment unit 101b can be variously selected as necessary. For example, in a water treatment device including a contaminant removal tank, an anaerobic filter bed tank, a contact filter bed tank, a treated water tank and a disinfection tank in the water treatment unit, as a filter medium filled in a contact filter bed tank as an aerobic treatment region The contact material according to the present invention can be applied. Furthermore, although the contact material C3 has been described in the configuration in the regular filling state in the above-described aspect, when the maximization of the substantial contact area of the treated water with respect to the biofilm is more important than the biofilm retainability. May be an embodiment in which the contact material is filled irregularly.

  Moreover, in the said embodiment, although the water treatment apparatus 100 which processes raw | natural water discharged | emitted from a general household, an apartment house, etc. was described, this invention is a commercial facility, a public facility, a factory other than an ordinary household, an apartment house. The present invention is also applicable to a water treatment apparatus that treats raw water discharged from such facilities.

DESCRIPTION OF SYMBOLS 100 ... Water treatment apparatus 101 ... Treatment tank main body 101a ... Accommodating space 101b ... Water treatment part 102 ... Inflow pipe 103 ... Outflow pipe 104 ... Manhole part 110 ... Precipitation separation tank 111 ... Peak cut part 112 ... Sludge storage part 113 ... Precipitation separation Part 114 ... Sludge circulation pump 130 ... Anaerobic filter bed 131 ... Peak cut part 132 ... Anaerobic filter bed 133 ... Anaerobic sludge transfer pump 134 ... Peak cut transfer pump 150 ... Aerobic filter bed tank 151 ... Contact aeration part 152 ... Biology Filtration part 153 ... Backwash pump 154 ... Diffuser pipes 155, 156, 157 ... Opening part 170 ... Treatment water tank 171 ... Circulation pump 172 ... Advection weir 190 ... Disinfection tank 191 ... Chemical cylinder C1 ... Filter medium C2 ... Anaerobic filter medium C3 ... Filter medium ( Contact material)
C4 ... carrier

Claims (2)

A treatment tank body having a storage space;
A water treatment unit provided in the accommodation space to treat the treated water;
A contact material filling region filled with a plurality of contact materials in the water treatment unit;
A biofilm retention mechanism for enhancing the biofilm retention of the contact material;
With
The contact material is a net-like roll body configured by extrusion molding of a thermoplastic resin containing a foam material ,
The contact material filling region is configured as an aerobic treatment region that performs an aerobic treatment of water to be treated by aeration of the contact material in the water treatment unit, and the contact material has a flow of the contact material. A plurality of the contact materials are filled in the aerobic treatment region so that the respective cylinder shafts are irregularly directed to each other in the blocked and fixed state ;
The biofilm holding mechanism is configured so that the surface roughness of the contact material is set so that the surface roughness (Ra) exceeds 20 [μm] due to foaming of the foam material during extrusion molding. It is configured as an uneven structure,
Due to the concavo-convex structure, the biofilm holding mechanism suppresses the biofilm attached to the contact material from being peeled off at the time when the temperature of the water to be treated in the contact material filling region is raised, thereby improving the biofilm holding ability. The water treatment apparatus characterized by including the biofilm peeling suppression part to raise . The water treatment device according to claim 1,
The biofilm retention mechanism includes a biofilm adhesion rate setting unit that increases the adhesion rate of the biofilm that adheres to the contact material at the start of use of the contact material, thereby enhancing the biofilm retention property. Water treatment equipment.

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