JP2006175400A - Phosphate ion solidification agent, phosphate ion solidification apparatus, and septic tank equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phosphate ion solidification agent, a phosphate ion solidification apparatus which can be maintained and controlled with a low load and is installable easily in a small scale septic tank for treating a phosphate ion-containing wastewater, and a septic tank provided with the apparatus. <P>SOLUTION: The phosphate ion solidification agent contains a multi-valent metal ion enclosed and fixed in hydrophilic gel. The phosphate ion solidification apparatus contains the phosphate ion solidification agent and is useful if it is used for a septic tank. The phosphate ion solidification apparatus may have a structure in which a column filled with the phosphate ion solidification agent is installed and target water containing phosphate ion to be treated is passed through the column, or in which a water-permeable container containing the phosphate ion solidification agent is immersed in an immersion tank and object water containing phosphate ion to be treated is passed through the immersion tank. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to phosphate ions for removing phosphate ions contained in drainage or sewage (hereinafter simply referred to as wastewater) discharged from detached houses, apartment houses, convenience stores, small business establishments, etc. The present invention relates to a solidifying agent, a phosphate ion solidifying device, and a septic tank including the same.

  When the purpose is to remove phosphate ions contained in the wastewater discharged from the above facilities, etc., supply ions of polyvalent metals such as iron, aluminum, calcium, etc. into the wastewater, and this and phosphate A reactive agglomeration method is often used in which solidification (or particleization) is caused by reacting with ions and then removed by precipitation, flotation or filtration. As a method for supplying polyvalent metal ions into the wastewater, for example, a metal material such as iron or aluminum is suspended in a liquid, and a voltage is applied to the metal material to pass an electric current. There is an electrolysis method in which polyvalent metal ions are dissolved (see Patent Document 1).

Further, as another method of supplying polyvalent metal ions into the waste water, there is a coagulant addition method in which an aqueous coagulant such as ferric chloride, polyferric sulfate, or polyaluminum chloride is supplied by an injection pump. Yes (see Patent Document 2). Furthermore, there are ion exchange resins, ion exchange methods using hydrotalcite-like clay minerals, adsorption methods using zirconium oxide and the like.
Japanese Patent No. 3506697 Japanese Patent Laid-Open No. 2003-136082

  In the electrolysis method described above, it is essential to provide an electrolyzer, a control device, and the like, and it is necessary to periodically replace it with a new one as the electrode material is consumed. In addition, the coagulant addition method requires provision of a coagulant injection device (pump), a control device, a coagulant storage tank, and the like, and periodic replenishment is required as the coagulant decreases. And since the above-mentioned apparatus is generally expensive, when it is incorporated into a small-scale waste water treatment apparatus or septic tank, the burden becomes large. On the other hand, the ion exchange method and the adsorption method require replacement or regeneration with a new one before the respective exchange capacity and adsorption capacity reach saturation. And, it is practically difficult to regenerate ion exchange materials and adsorbents in places where small-scale wastewater treatment equipment and septic tanks are installed. large.

  The present invention is a phosphate ion solidifying agent and a phosphate ion solidifying device that are less burdensome for maintenance and can be easily provided in a small-scale septic tank or the like for treating phosphate ion-containing wastewater. And it aims at providing a septic tank provided with it.

The present invention relates to the following.
1. A phosphate ion solidifying agent in which polyvalent metal ions are entrapped and immobilized in a hydrophilic gel.
2. Item 2. The phosphate ion solidifying agent according to Item 1, wherein the polyvalent metal ion is ionically bonded to the carboxyl group of the hydrophilic gel.
3. Item 7. A phosphate ion solidifying apparatus comprising the phosphate ion solidifying agent according to Item 1 or Item 2.
4). Item 4. The phosphate ion solidifying device according to item 3, wherein a column filled with a phosphate ion solidifying agent is provided, and the phosphate ion-containing treated water is passed through the column.
5. Item 4. The phosphate ion solidifying device according to item 3, wherein a water-permeable container containing a phosphate ion solidifying agent is immersed in an immersion tank, and the phosphate ion-containing treated water is passed through the immersion tank.
6). Item 6. A septic tank comprising the phosphate ion solidifying device according to any one of Items 3 to 5.
In addition, the gel here is a dispersion system made of two components, a solid and a liquid, and the dispersion system particles are a non-flowable semi-solid as a whole system. The solid portion that supports the basic structure of the gel often consists of a crosslinked polymer having a three-dimensional structure.
Furthermore, free water areas exist in the gaps of the polymer skeleton having the three-dimensional structure of the gel. A form in which the predetermined substance is enclosed in the free water region with a polymer skeleton, or a form in which the predetermined substance is enclosed in a capsule (microcapsule) formed of a film is referred to as comprehensive fixing.

When the phosphate ion solidifying agent of the present invention is brought into contact with the water to be treated in which phosphate ions are present, the polyvalent metal ions comprehensively immobilized on the hydrophilic gel react with phosphate ions to become insoluble or Since the hardly soluble polyvalent metal salt of phosphoric acid precipitates in the water to be treated, phosphate ions can be easily removed from the water to be treated. Therefore, at this time, there is no need for heavy equipment such as an electrolytic device and a flocculant injection device. Further, regeneration is not necessary like an ion exchange agent or an adsorbent. Further, since a large amount of polyvalent metal ions to be comprehensively immobilized can be retained in the hydrophilic gel, more phosphate ions can be removed.
Moreover, according to the phosphate ion solidification apparatus of this invention, it can be set as the simple structure which only makes a column or a dipping tank fill or accommodate a phosphate ion solidification agent. In addition, since the phosphate ion solidifying agent only needs to be replenished with disappearance at the time of maintenance, a regeneration operation is unnecessary and the burden on maintenance is small.
Furthermore, the septic tank of the present invention can be easily equipped with a phosphate ion solidifying device, and since phosphorus can be removed in addition to BOD and nitrogen, highly treated water can be obtained.

Hereinafter, the phosphate ion solidifying agent of the present invention will be described.
The hydrophilic gel agent used as the raw material of the phosphate ion solidifying agent according to the present invention is only required to be capable of comprehensively fixing polyvalent metal ions. For example, the hydrophilic gel agent is hydrophilic and has a carboxyl group, and has a carboxy group. As long as sodium or hydrogen bonded to a polyvalent metal salt is mixed with an aqueous solution of a polyvalent metal salt, the polyvalent metal may be substituted and gelled. More specifically, polymers such as alginic acid, cellulose, and pectin are used. Polysaccharides with carboxyl groups bonded (including those modified by introducing carboxyl groups), such as sodium alginate, sodium carboxymethyl cellulose (abbreviated as Na-CMC), methoxy pectin, etc. It is used in a form such as sodium polyacrylate, and particularly preferably sodium alginate and Na-CMC are used. These hydrophilic gels are used in 0.01 to 30% aqueous solution, preferably 0.1 to 20% aqueous solution or hydrophilic solvent solution. In addition, you may add proteinaceous polymers, such as high molecular polysaccharides, such as carrageenan, agar, and cellulose, casein, and gelatin, to the said gel agent.

  Examples of the polyvalent metal include aluminum, calcium, iron, barium, manganese, magnesium, and zinc. Preferably, aluminum, calcium, and iron are used. These are preferably used in the form of a water-soluble salt such as a sulfate of a polyvalent metal in the production of a phosphoric acid solidifying agent, preferably 0.01 to 50% by weight, more preferably 0.1 to 50% by weight. % Aqueous solution.

  The phosphate ion solidifying agent can be used in various shapes. For example, when a gel agent aqueous solution is dropped from a narrow mouth into an agitated polyvalent metal salt aqueous solution, it can be gelled in a granular form, and can be gelled in a string form when continuously fed from the narrow mouth without any breaks. Further, when the polyvalent metal salt aqueous solution and the gel agent aqueous solution are mixed, the entire solution can be gelled, and therefore, it can be formed into a block shape, a plate shape, or a sheet shape. In addition, by impregnating or holding an aqueous gel agent solution in a woven fabric, non-woven fabric, etc., and immersing this in an aqueous solution of a polyvalent metal salt, a plate or sheet having a woven fabric, non-woven fabric, etc. as a core material can be obtained. . Therefore, as the phosphate ion solidifying agent, it can be used in various shapes or by cutting the formed gel.

  The amount of polyvalent metal added to the hydrophilic gel of the phosphate ion solidifying agent is almost determined by the amount of substitution with sodium or hydrogen at the carboxyl group terminal, but retains the polyvalent metal ion more than the amount of substitution. You can also There is a free water area in the gap of the polymer skeleton (matrix) having the three-dimensional structure of the hydrophilic gel, so that a polyvalent metal ion is enclosed in the free water area with a matrix, or like a microcapsule. What is necessary is just to carry out comprehensive fixation. In general immobilization, the gel solution and the polyvalent metal salt aqueous solution prepared separately may be mixed and then rapidly dropped into the polyvalent metal salt aqueous solution. Alternatively, as described above, the aqueous solution of the polyvalent metal salt and the aqueous gel agent solution may be mixed to gel the entire solution. Furthermore, if the narrow mouth is made into a double tube, a polyvalent metal salt aqueous solution is injected from the inner tube, a gel agent aqueous solution is injected from the outer tube, and dropped into the stirred polyvalent metal salt aqueous solution to form a microcapsule. It can also be gelled. In this way, by entrapping and immobilizing polyvalent metal ions, a large amount of polyvalent metal can be added to the phosphate ion solidifying agent, whereby a large amount of phosphate ions can be removed.

Next, the phosphate ion solidifying device of the present invention will be described. This is an apparatus for forming a phosphate ion solidifying agent composed of the above-mentioned hydrophilic gel into various shapes, filling the container into a container, immersing or suspending it, and bringing it into contact with phosphate ion-containing waste water. Here, solidification of phosphate ions is considered to be performed by the following mechanism.
When the polyvalent metal ions that are comprehensively immobilized on the hydrophilic gel come into contact with phosphate ions in the wastewater, the polyvalent metal ions react with the phosphate ions to become insoluble or hardly soluble polyvalent metal salts. To solidify. The insoluble or hardly soluble polyvalent metal salt aggregates by adhering to colloidal particles, microparticles, or SS (suspended particles) present in the waste water, and is further solidified into a larger mass. Therefore, phosphate ions can be removed from the waste water by solid-liquid separation of the solidified particles by means such as precipitation, flotation or filtration. In addition to this, when polyvalent metal ions are included and immobilized in the gel, the polyvalent metal ions diffuse from the inside of the gel to the outside of the gel because there is a difference in concentration between the inside and outside of the gel. Therefore, a large amount of phosphate ions can be solidified, that is, phosphate ions can be removed.

  On the other hand, when the polyvalent metal added to the carboxyl group terminal is replaced with sodium or hydrogen in the wastewater, the gel material in this portion is gradually dissolved in the wastewater. Therefore, the phosphate ion solidifying agent disappears in proportion to the phosphate ion concentration in the waste water. Therefore, in actual operation, it is sufficient to replenish the phosphate ion solidifying agent as appropriate. Become. Conventional ion exchangers and adsorbents need to be regenerated, whereas the phosphate ion solidifying agent does not need to be regenerated. This can greatly reduce the restrictions and burden on maintenance for removing phosphorus.

  FIG. 1 shows an embodiment of a phosphate ion solidifying device for phosphate ion-containing wastewater, and a schematic sectional view thereof is shown. The phosphate ion solidifying device 1 is composed of a column 3 filled with a granular phosphate ion solidifying agent 2, and allows phosphate ion-containing waste water to pass through the column 3. The column 3 has an inlet 4 for the water to be treated (phosphate ion-containing wastewater), and an outlet 5 of the water to be treated that has passed through the packed bed is disposed in a section opposite to the inlet 4. The outlet 6 is provided in the upper part of the advection port 5. A water-permeable member 7 that does not allow the phosphate ion solidifying agent 2 to pass but passes water to be treated is provided at the upper and lower portions of the packed bed of the phosphate ion solidifying agent 2. The upper water-permeable member 7 can be removed, and when a filter such as a mesh is provided at the lower part of the advection port 5, the lower water-permeable member 7 may be omitted. It is preferable that the phosphate ion solidifying device 1 is provided with a diffuser member 8 below the lower water-permeable member 7 and continuously or intermittently sends air from an external blower (not shown) for bubbling. SS is often present in the water to be treated, and this is also for preventing an increase in water flow resistance due to the supplementation of SS of the phosphate ion solidifying agent 2. In addition, you may remove | eliminate when it does not produce the increase in water flow resistance. Moreover, in FIG. 1, although the flow direction of the to-be-processed water of the column 3 is made into the downward flow, this can also be made into an upward flow.

  Here, processing functions and the like will be described. The water to be treated containing phosphate ions enters from the inlet 4 and descends the packed bed of the phosphate ion solidifying agent 2. At this time, the phosphate ion solidifying agent 2 and phosphate ions react to form an insoluble or hardly soluble phosphate, which is released to the water to be treated. The water to be treated that has passed through the column 3 passes through the advection port 5 with the phosphate and is discharged from the outlet 6. Thereafter, the solidified phosphate may be separated by guiding it to a precipitation tank, a floating tank, a filtration tank or the like (not shown).

  FIG. 2 is another example of a phosphate ion solidifying device for phosphate ion-containing wastewater, and shows a schematic cross-sectional view thereof. The phosphate ion solidifying device 1 is composed of a dipping tank 10 in which a sheet-like phosphate ion solidifying agent 2 is passed through an aqueous container 9 and suspended therefrom, and the phosphate ion-containing wastewater passes through the dipping tank 10. It is something to be made. The immersion tank 10 has an inlet 4 for water to be treated (phosphate ion-containing wastewater), and an outlet 5 of the water to be treated that has passed through the immersion tank 10 is provided on a side opposite to the inlet 4. The outlet 6 is provided above the advection port 5. In FIG. 2, three water-permeable containers 9 containing the phosphate ion solidifying agent 2 are suspended, but the number may be determined as appropriate. In addition, it is preferable that the air diffusion member 8 is provided below the water-permeable container 9 and air is continuously or intermittently sent from an external blower (not shown) for bubbling. This is to promote material diffusion at the interface between the water to be treated and the phosphate ion solidifying agent 2. In addition, in FIG. 2, although the flow direction of the to-be-processed water of the immersion tank 10 is made into the downward flow, this can also be made into an upward flow. Examples of the water-permeable container include a container having a hole through which water can pass and a net-like container.

  The processing functions and the like are the same as those in the case of FIG.

Next, a septic tank provided with a phosphate ion solidifying device will be described.
In the septic tank 15, a first anaerobic treatment tank 17, a second anaerobic treatment tank 18, an aerobic treatment tank 19, a filtration tank 20, and a disinfection tank 26 are arranged from the upstream side. The phosphate ion solidifying device 1 is disposed above the second anaerobic treatment tank 18 and is provided with a diffuser member 8 for bubbling air from the blower 33. There is an advection pipe 21 between the aerobic treatment tank 19 and the filtration tank 20, and the first anaerobic passage is made in the advection pipe 21 by passing the treated water treated in the aerobic treatment tank 19 to the circulation pipe 45. A circulation pump 35 is provided to be returned to the treatment tank 17. And the phosphate ion solidification apparatus 1 is connected in the middle of the circulation pipe 45 located above the second anaerobic treatment tank 18. Therefore, a part of the water to be treated that has been treated in the aerobic treatment tank 19 and has flowed into the advection pipe 21 is pumped up to the circulation pipe 45 positioned above by the circulation pump 35 (abbreviated as circulation water). The circulating water flowing down the circulation pipe 45 enters the phosphate ion solidifying device 1, where the phosphate ions become phosphates, and then flows down the circulation pipe 45 in the first anaerobic treatment tank 17. Enter the inflow baffle 40.

  Phosphate (insoluble or sparingly soluble) transferred in the circulating water is accumulated in the first anaerobic treatment tank 17 by adhering to sludge or the like of the filter bed 28 or by sedimentation due to aggregation of particles. The Such an action is also performed in the second anaerobic treatment tank 18. Thereby, phosphate ions can be removed from the waste water. In addition, the phosphate (insoluble or hardly soluble) accumulated in the first anaerobic treatment tank 17 and the second anaerobic treatment tank 18 is extracted together when the sludge and the like in the septic tank are periodically extracted. . Moreover, in FIG. 4, although the phosphate ion solidification apparatus 1 is provided in the upper part of the 2nd anaerobic processing tank 18, it arrange | positions in the upper part of the 1st anaerobic processing tank 17, the upper part of the aerobic processing tank 19, etc. You can also Further, when the phosphate ion solidifying device 1 is disposed in the first anaerobic treatment tank 17, the second anaerobic treatment tank 18 or the aerobic treatment tank 19, the manhole 16 is used from the viewpoint of replenishment of the phosphate ion solidifying agent. It is preferable to arrange at a lower position. In addition, although the phosphate ion solidification apparatus 1 has shown the substantially square shape by planar view, circular, an ellipse, etc. may be sufficient.

  Here, the purification tank 15 will be described in more detail. The anaerobic treatment tank is composed of a first anaerobic treatment tank 17 and a second anaerobic treatment tank 18, and the first anaerobic treatment tank 17 has an inlet 24. Is provided. Further, a box-shaped inflow baffle 40 having an upper portion and a lower portion is provided below the inflow port 24, and an advection pipe 27 (or an advection port) is provided on the partition wall opposite to the inflow port 24. . The first anaerobic treatment tank 17 precipitates and separates solid matter that tends to settle in the inflowing sewage, and concentrates and stores it at the bottom of the tank. At this time, a part of the sludge stored at the bottom of the tank becomes a scum by an anaerobic biological reaction, rises and is stored at the top of the tank. Moreover, in the filter bed 28, an anaerobic biological reaction is advanced.

  The second anaerobic treatment tank 18 has the same processing function as the first anaerobic treatment tank 17, sludge storage at the tank upper part by scumming, organic matter decomposition at the filter bed 29, and sedimentation at the tank bottom. Store sludge. An advection pipe 31 is provided on the partition wall on the aerobic treatment tank 19 side, and a transfer pump 32 is attached in the advection pipe 31. In the above anaerobic treatment tanks (the first anaerobic treatment tank 17 and the second anaerobic treatment tank 18), most of the nitrogen content contained in the water to be treated is converted into ammonia nitrogen as the organic matter is decomposed. The filter bed 28 and the filter bed 29 are not necessarily required and can be removed.

  In each upper part of the first anaerobic treatment tank 17 and the second anaerobic treatment tank 18, the liquid level is the highest water level (HWL) in order to reduce the fluctuation of the inflowing sewage and transfer it to the next tank. And the flow volume adjustment part 30 which can be changed between minimum water levels (LWL) is provided. In this case, the water level in the first anaerobic treatment tank 17 and the second anaerobic treatment tank 18 depends on whether the amount of inflow of sewage is larger or smaller than the liquid feed amount of the transfer pump 32. W. L and H.M. W. It fluctuates between L. The septic tank 15 is provided with a flow rate adjusting unit 30 so that the amount of inflow of sewage is averaged, and an anaerobic treatment tank (first anaerobic treatment tank 17, second anaerobic treatment tank 18), an aerobic treatment tank 19, and filtration. Each function of each tank such as the tank 20 is satisfactorily exhibited. The transfer pump 32 is an air lift pump that uses air supplied from the blower 33 in this embodiment, but an intermittent metering pump that pumps air into a sealed container, an electric submersible pump, or the like can also be used.

  In the aerobic treatment tank 19, an air diffuser 34 for aeration is disposed at the bottom, and the air supplied from the blower 33 is ejected. The aerobic treatment tank 19 forms a bed filled with a microorganism adhesion material (also referred to as a carrier, a microorganism carrier, a contact material, or a contact filter material). Here, the bed filled with the microorganism adhesion material is a fluidized bed that flows together with the liquid by the air ejected from the microorganism adhesion material, a fixed bed in which only the liquid moves, or a combination of both the fluidized bed and the fixed bed. Also good. The aerobic treatment tank 19 performs aeration so that the microorganism-adhering material (with microorganisms attached) and the liquid are sufficiently mixed, or the microorganism-adhering material and the liquid are in positive contact with each other. It oxidizes and decomposes organic matter, nitrifies ammonia nitrogen, and phosphorus content becomes phosphate ions.

  The shape of the microorganism-adhering material can be various, such as plate-like, net-plate-like, loofah-like, porous, cylindrical, rod-like, skeletal spherical, string-like, and granular, irregular lump, cube, fiber lump, etc. What was processed into the shape can be used. Of these microorganism-adhering materials, those having a shape that is relatively small and easy to flow are preferably used for the fluidized bed, and those having a shape that is difficult to block and fix by the adhering microorganisms or particles are used for the fixed bed. Preferably used. The material of the microbial adhesion material is made of synthetic resin such as vinylidene chloride, polyvinyl formal, polyurethane and melamine resin, inorganic processed material such as ceramics and silica sand, fossil processed material such as anthracite, activated carbon, etc. Any one having one or more, a polyolefin resin such as polyethylene and polypropylene, polystyrene, and the like having a specific gravity of about 1 or 1 or less can be used.

  In one section in the aerobic treatment tank 19, a convection pipe 21 (or a convection port) and a filtration tank 20 are arranged. The advection tube 21 is provided with an opening having a shape such as a mesh and a slit so that the microorganism-adhering material in the aerobic treatment tank 19 does not flow out in the vicinity of the bottom, and the upper part is also opened, and the water level is transferred to the filtration tank 20. An advection port is provided. The advection pipe 21 is provided with a circulation pump 35 that returns a part of the aerobic treated water treated in the aerobic treatment tank 19 to the first anaerobic treatment tank 17. The circulation pump 35 and the first anaerobic treatment tank 17 are connected by the circulation pipe 45, the phosphate ion solidifying device 1, and the circulation pipe 45. The circulation pipe 45 is provided in addition to removing phosphate ions, by returning the aerobic treated water by the circulation pump 35, thereby pulling SS floating in the aerobic treatment tank 19 or easily precipitated SS. This is because it can be extracted, and when there is nitrate nitrogen, it can be denitrified by biological action in the first anaerobic treatment tank 17 and the second anaerobic treatment tank 18. The return of the treated water from the circulation pump 35 may be continuous or intermittent. In this embodiment, the circulation pump 35 is an air lift pump that supplies air from the blower 33. However, an intermittent metering pump, an electric pump, or the like that pumps air into a sealed container can also be used.

  The filtration tank 20 has a filter layer filled with a filter medium for capturing SS (floating matter) present or remaining in the aerobic treated water that is advancing, and below or below the filter layer is a filter layer. An air diffusing tube 36 is disposed for cleaning. In addition, an air lift pump 37 is also provided at the bottom of the filtration tank 20 for extracting the cleaning waste water during cleaning. In this embodiment, the normal water flow direction is a downward flow, but it can also be an upward flow. In the filtration tank 20, aerobic biological treatment also proceeds due to the presence of dissolved oxygen carried over from the aerobic treatment tank 19. Air from the blower 33 is sent to the air diffuser 36 and the air lift pump 37. The air diffuser 36 and the air lift pump 37 may use another air blower as an air source. An electric pump may be used instead of the air lift pump 37.

  There is a disinfection tank 26 in the downstream of the advection pipe 38 (or the advection opening) in the filtration tank 20, and the discharge opening 23 is provided in the disinfection tank 26.

Next, a method for operating the septic tank will be described.
(Normal operation)
The inflowing sewage enters the first anaerobic treatment tank 17 from the inflow port 24 as indicated by the solid line arrow in FIG. 4, where solid-liquid separation and anaerobic biological treatment are performed. The advection liquid that has passed through this enters the second anaerobic treatment tank 18 and further undergoes solid-liquid separation and anaerobic biological treatment. Further, in the flow rate adjusting unit 30, the sewage is transferred to the next anaerobic treatment tank 19 by the transfer pump 32 while absorbing and mitigating fluctuations in the amount of sewage flowing into the first anaerobic treatment tank 17 and the second anaerobic treatment tank 18. Quantitative transfer to

  The water flowing into the aerobic treatment tank 19 is subjected to aerobic biodegradation by the air discharged from the aeration tube 34 and the microorganism adhesion material. A part of the decomposed organic matter in the sewage adheres to the microorganism-adhering material while being converted into microorganisms, and a part of the organic matter floats in the liquid and exists as SS. The aerobic treatment water from the aerobic treatment tank 19 flows into the advection tube 21 through an opening at the lower portion of the advection tube 21. A part of the aerobic treated water here enters the phosphate ion solidifying apparatus 1 through the circulation pipe 45 continuously or intermittently by the circulation pump 35. In the phosphate ion solidifying device 1, phosphate ions become phosphates and are returned to the first anaerobic treatment tank 17 together with the circulating water. The remaining aerobic treated water enters the filtration tank 20 through the upper advection port of the advection pipe 21.

  In the filtration tank 20, SS in the advection water (aerobic treated water) is captured and removed, and biological treatment also proceeds. The advection water from which the organic matter and SS have been removed is discharged from the advection pipe 38 through the disinfection tank 26 as treated water from the outlet 23. Here, when the operation is continued for a long time, SS accumulates in the filtration layer 20 and the water flow resistance increases and a predetermined water flow amount cannot be obtained, or the SS trapping capacity is lowered and SS leaks ( leak. Therefore, the filtration tank 20 is cleaned before such a state is reached.

(Filter tank washing operation)
When the water level of the filtration tank 20 rises to a predetermined water level or when a predetermined time set by a timer comes, the cleaning operation is started. Here, in the case of the timer setting, the cleaning operation is preferably set at a time zone in which sewage is less flowing, for example, around 14:00 to 16:00, around 1 to 5 o'clock, around 10 to 11 o'clock in ordinary households. . This is because, in this time zone, the water level of the flow rate adjusting unit 30 is normally near the lowest water level, so that the washing waste water of the filtration tank 20 can be received. In cleaning, first, air is discharged from the air diffusion pipe 36, the filter medium in the filtration tank 20 is disturbed, and SS is peeled off. At this time, the air lift pump 37 is operated to draw the cleaning wastewater from the bottom of the filtration tank 20 and transfer it to the first anaerobic treatment tank 17 through the circulation pipe 45. At this time, the entire amount of the washing waste water is preferably extracted. In addition, you may return washing | cleaning waste_water | drain with piping different from the circulation pipe 45. FIG. The cleaning of the filtration tank 20 is completed by stopping the air discharge from the air diffuser 36 and the air lift pump 37 after a predetermined time. The above washing operation is performed once or a plurality of times a day.

Granular gelation was tested using sodium alginate and Na-CMC as the hydrophilic gel, and an aqueous polyferric sulfate solution as the gelling agent. In addition, sodium alginate (SIGMA CHEMICAL.CO _, low viscosity type) and Na-CMC (Daicel Chemical Industries, Ltd., # 1330) were adjusted to 4 mass% aqueous solution and 1.5 mass% aqueous solution, respectively. An aqueous polyferric sulfate solution (Nittetsu Mining Co., Ltd., polyiron) was used after diluting the stock solution twice (5.5% by mass as trivalent iron).
While stirring the aqueous ferric sulfate solution in a beaker with a magnetic stirrer, using a dropper with a 2 mm aperture, a sodium alginate aqueous solution and an Na-CMC aqueous solution were dropped into each beaker. As a result, an iron with a diameter of about 3 mm was obtained. A spherical gel of alginic acid, a spherical gel of iron-CMC having a diameter of about 2 mm was obtained.
The amount of iron ions in the gel was measured as follows. First, the gel was put into distilled water and crushed, and then acidified with sulfuric acid, left for 3 hours, and filtered using filter paper. The total amount of iron ions in the filtrate was measured using a digital simple water quality meter (L-8800 type, manufactured by Kyoritsu Chemical Laboratory Co., Ltd.). As a result, when sodium alginate was used as the hydrophilic gel, iron cation was about 30 mg per 1 g of the gel. In addition, when Na-CMC was used as the hydrophilic gel, iron cation was about 40 mg per 1 g of the gel.

  Granular gelation was tested using sodium alginate as the hydrophilic gel, and ferrous sulfate as the entrapping immobilization of iron ions, and an aqueous polyferric sulfate solution as the gelling agent. Sodium alginate was adjusted to a 2.6% by mass aqueous solution, and ferrous sulfate was adjusted to a 1.0% by mass aqueous solution. As a result of dropwise addition to a ferric sulfate aqueous solution in the same manner as in Example 1, a spherical gel of iron-alginic acid having a diameter of about 3 mm and including iron ions was fixed.

The phosphate ion solidifying agent (hydrophilic gel, iron-alginate spherical gel having a diameter of about 3 mm) prepared in Example 1 was packed in a column, and a phosphate ion removal test was performed by continuous operation. The test conditions are as follows. The inner diameter of the column was 31 mm, the packing height of the phosphate ion solidifying agent was 200 mm, LV (linear velocity) was 0.62 m / h, and SV (superficial velocity) was 3 ^-h . For the phosphate ion-containing wastewater, an aqueous solution of dipotassium hydrogen phosphate (4.3 mg / L as phosphorus in the phosphate state) was used as simulated water, and this was continuously supplied to the column by a roller pump. The test results are shown in FIG. The passing water from the column became slightly cloudy due to the solidification of the phosphate. The phosphorus concentration in the passing water for each elapsed time was filtered with 0.45 μm filter paper, and the filtrate was measured. The X axis in FIG. 5 represents the ratio (QV) of the amount of treated water to the filling capacity of the phosphate ion solidifying agent. The phosphorus concentration of treated water has reached 1 mg / L or less even at the time of QV16. From these results, it was confirmed that the hydrophilic gel has the performance as a phosphate ion solidifying agent (phosphorus removing agent).

The schematic sectional drawing which showed one Example of the phosphate ion solidification apparatus of this invention. The schematic sectional drawing which showed another Example of the phosphate ion solidification apparatus of this invention. The schematic plan view which showed one Example of the septic tank provided with the phosphate ion solidification apparatus of this invention. The schematic sectional drawing in the AA surface of the septic tank shown in FIG. The figure which shows the test result of the phosphorus solidification performance (phosphorus removal performance) by the phosphate ion solidification agent of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Phosphate ion solidification apparatus 2 ... Phosphate ion solidification agent 3 ... Column 4 ... Inlet 5 ... Transfer port 6 ... Outlet 7 ... Water-permeable member 8 ... Air diffuser member 9 ... Water-permeable container 10 ... Immersion tank 15 ... Septic tank 16 ... Manhole 17 ... First anaerobic treatment tank 18 ... Second anaerobic treatment tank 19 ... Aerobic treatment tank 20 ... Filtration tank 21 ... Advection pipe 23 ... Outlet 24 ... Inlet 26 ... Disinfection tank 27 ... Advection tube 28 ... filter bed 29 ... filter bed 30 ... flow rate adjusting unit,
31 ... Advection pipe 32 ... Transfer pump 33 ... Blower 34 ... Aeration pipe 35 ... Circulation pump 36 ... Aeration pipe 37 ... Air lift pump 38 ... Advection pipe 40 ... Inflow baffle 45 ... Circulation pipe

Claims (6)

A phosphate ion solidifying agent in which polyvalent metal ions are entrapped and immobilized in a hydrophilic gel. The phosphate ion solidifying agent according to claim 1, wherein the polyvalent metal ion is ionically bonded to the carboxyl group of the hydrophilic gel. A phosphate ion solidifying device comprising the phosphate ion solidifying agent according to claim 1. The phosphate ion solidifying apparatus according to claim 3, wherein a column filled with a phosphate ion solidifying agent is provided, and the phosphate ion-containing water to be treated is passed through the column. The phosphate ion solidifying device according to claim 3, wherein a water-permeable container containing a phosphate ion solidifying agent is immersed in an immersion tank, and the phosphate ion-containing treated water is allowed to pass through the immersion tank. A septic tank provided with the phosphate ion solidification device according to any one of claims 3 to 5.

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