JP4129953B2 - Phosphorus recovery equipment from barn sewage - Google Patents

Description

  The present invention relates to a technology for recovering resources from barn sewage, and in particular, to take special measures such as adding an additive containing a basic reagent or a coagulant to barn sewage so that livestock farmers can easily carry it out. The present invention also relates to a method and a recovery device for easily recovering phosphorus and phosphorus compounds of livestock sewage, and also relates to a technique for purifying livestock sewage.

  Recently, livestock management has become large scale and specialized throughout the country, but there are many cases that do not involve expansion of farmland within management. As a result, livestock excrement tends to be concentrated and unevenly distributed. However, due to the establishment of relevant laws and regulations, proper treatment of livestock excrement is strongly demanded.

  For sewage sewage containing livestock excreta, various types of purification equipment using anaerobic and aerobic treatment technologies have been developed (stock raising environment conservation theory, pages 62-97, wisdom). (Dou, 1998).

  However, it is known that the anaerobic treatment technique sufficiently removes organic substances from the sewage in barn, but is insufficient to remove nitrogen and phosphorus. Among the aerobic treatment techniques, the standard activated sludge method is known to sufficiently remove organic substances in barn sewage but is insufficient to remove nitrogen and phosphorus. In the intermittent aeration activated sludge method, organic matter and nitrogen in the barn sewage are sufficiently removed.However, when storing excess sludge, phosphorus accumulated in the sludge is re-released when it is anaerobically treated. It is known that it becomes unstable. As described above, there is no firm technique for collecting and recycling phosphorus in sewage sewage, and its development is urgently needed.

  Here, as a technique for recovering phosphorus, in the field of sewage / sewage treatment, soluble phosphorus is artificially insoluble and recovered for anaerobic treatment of sewage / sewage or sludge treatment thereof. As a technology, the magnesium ammonium phosphate (MAP) method has been proposed (Sewage Association Journal, Vol. 28, No. 324, pp. 68-77, 1991, JP-A-62-262789, JP-A-1-119392 Gazette).

  In this technique, a pH adjusting agent such as caustic soda and magnesium which is a deficient component are added to the waste water to be treated and mixed to induce a MAP reaction, so that soluble phosphorus is insolubilized and recovered. The MAP reaction is a reaction in which, when phosphate ions, ammonium ions, and magnesium ions are present in water, they are bonded in equimolar amounts under alkaline conditions to form insoluble MAP. This MAP is excellent in sedimentation property and can be easily separated by precipitation (Sheetin Technology, Vol. 22, No. 1, pages 1-4, 1996). However, this technology requires the addition of a chemical called magnesium in addition to the pH adjuster, which makes the operation including pH control cumbersome and increases the operating costs including reagents. It is difficult to recommend to farmers.

  As a phosphorus recovery technology that solves a part of this problem, there is an improved method in which pH is adjusted by aeration of the sewage to be treated, and only the magnesium is added (water and wastewater, Vol. 29, No. 7, 636). -640, 1987 and JP-A 63-84696). According to this method, carbon dioxide gas or the like dissolved in the target water is expelled by aeration, and as a result, the pH of the treated sewage is increased, and the addition of a pH adjuster is unnecessary. An apparatus for implementing this technique has also been proposed (Japanese Patent Laid-Open No. 11-151500). This apparatus is a MAP aeration tank. The target water supply port provided in the aeration tank, the magnesium salt supply means, the treated water drainage means provided in the upper stage, and the crystal as a fluidized bed. It is provided with an air jetting means provided in the vicinity of the bottom for forming, and an outlet for the grown and enlarged crystal provided below the air jetting means, and is also a dephosphorization device.

In particular, when this type of livestock sewage is targeted, it is known that the target sewage contains a high concentration of magnesium, so that a MAP reaction can be induced only by aeration without using any chemicals. Yes. A device has been proposed in which an aeration cylinder is provided inside the settling tank, and the wastewater to be treated is aerated at the site to solidify and crystallize soluble phosphorus in the wastewater, and remove and recover the precipitate. It has been disclosed that most of the phosphoric acid component in the wastewater to be treated can be crystallized and recovered by precipitation (Journal of the Japanese Society of Pig Farming, Vol. 39, No. 2, pp. 101-111, 2002). It is also known that the MAP obtained here can be used as a fertilizer in arable land.
JP 62-262789 A Japanese Unexamined Patent Publication No. 01-119392 JP 63-084696 JP Japanese Patent Laid-Open No. 11-151500 Livestock Environment Conservation Theory, 62-97, Yokendo, 1998 Journal of Sewerage Society, 28, 324, 68-77, 1991 Fresh water technology, Vol. 22, No. 1, pp. 1-4, 1996 Water and wastewater, 29, 7, 636-640, 1987 Journal of Japanese Society of Pig Farming, Vol.39, No.2, pp. 101-111, 2002

  The first problem related to the above-described prior art is that pH management is indispensable because technical means related to MAP and HAP use a coagulant. However, the use of chemicals and their management impose an excessive burden on livestock farmers in the treatment of sewage, so the addition of coagulants should be avoided.

  The second problem is that although it is known that a simple aeration method can be adopted, long-time operation is impossible. A scale is generated in the treatment tank, and the pipe strainer is further clogged, which hinders operation. In order to avoid this, it is often necessary to clean the treatment tank, so it can be said that this aeration method is also cumbersome.

  The inventor has already reported on the advantages and disadvantages of the alkali addition method and the aeration method (Techno Innovation, 45, 23 pages, 2002, see Table 2), but in the aeration method that is easy to adopt for livestock farmers, There is an urgent need to improve the shortcomings.

  There is also known a device that provides an exposure cylinder inside the settling tank and aerates the water to be treated to solidify and crystallize the soluble phosphorus in the target wastewater, thereby removing and recovering the precipitate as MAP fertilizer. Nevertheless, as described above, there are various problems when the apparatus is actually operated.

  From the viewpoint of practical livestock sewage purification technology, first, considering durability and mechanical strength of the equipment members, usually stainless steel (for example, SUS304, etc.) will be selected. A part of the crystals produced in (1) adheres to the inner wall of the exposure cylinder, thereby reducing the effective aeration volume in the exposure cylinder, and thus reducing the efficiency of crystal precipitation recovery.

  Secondly, according to this technique, crystals are precipitated together with fine organic substances coexisting in the target wastewater, so that the crystallized substances are recovered together with these organic substances. When actually reusing, it is necessary to go through means and processes such as dehydration and composting, which requires considerable cost and time for man-hours and processing. Furthermore, it is predicted that the concentration of crystals in the compost is different for each livestock farmer. When used as compost on farmland, it is necessary to check the concentration one by one before use. For this reason, there is also a demand for a technique for recovering the produced crystals by a technique that does not mix a large amount of organic substances.

  These problems can be solved as follows.

First, the first problem, the aeration tube provided within treating tank, the device for collecting by crystallizing the solubility phosphorus in barns sewage by aerating the barn sewage in the site, the entire aeration tube rubber It is composed of a material having a crystal adhesion repellent performance represented by the above, and the solution technique is to prevent the adhesion of crystallized substances to the inner wall of the exposed cylinder and improve the recovery efficiency of phosphorus-containing precipitates. , it is possible to implement the recovery of Ririn containing precipitate by this means efficiently.

The second problem is the device you recovered by crystallizing the solubility phosphorus in barns sewage by aerating the barn sewage in the site aeration tube provided within treating tank, with stainless steel in this aeration cylinder metal typified, or sinking crystallization phosphorus capture member made from water-swellable material typified by lauan, and solutions to yield Kai adhere crystallization phosphorus deposited on the surface of the member Thus, by using this crystallized phosphorus capturing member , the problem of improving the efficiency of crystallized phosphorus recovery is solved. An example of the crystallized phosphorus capturing member is a stainless steel wire mesh.

  The specific solution is as follows.

The apparatus invention according to the first to third aspects will be described with reference to FIGS.

The present invention, wastewater inlet pipe is barn sewage introduction means for introducing a barn sewage (22), the process water tank (10 with when water a slaughter house sewage sedimentation unit with phosphorus-containing precipitate is deposited on co (12) and), in order to aerate slaughter house sewage provided treatment water tank (10), which diffuser the gas supplied through the vent pipe is a hiking means from the air supply source (38) and (36) a diffuser (34) is air diffuser means provided in the processing water tank (10), aeration tube made of partition walls surrounding the barn sewage in the aeration process containing bubbles formed by the diffuser (34) (30) And a collection port (14) which is a sediment collection means provided below the sedimentation section (12) of the treated water tank (10), and a slaughterhouse sewage derivation pipe which is a sewage sewage derivation means for discharging aerated sewage ( 24) .
Processing from the management aquarium sewage introduction pipe provided above the (10) supply port (22) (20), barn sewage Ru is supplied to the processing water tank (10). Also from the diffuser disposed to substantially contact (34) to the lower end of the 曝 cylinder (30) is supplied with gas, phosphorus-containing compound is deposited from the gas bubbles containing wastewater Te 曝 cylinder (30) inside odor, precipitation has been precipitated portion of the phosphorus-containing compound is processed water tank (10) to precipitate below (12), phosphorous from livestock barn sewage without to deposit phosphorus-containing product precipitated as a phosphorus-containing precipitate (18) It is a recovery device .

Further, the present invention is a phosphorus recovery apparatus provided with a capturing tool (40) which is a capturing means for capturing crystallized phosphorus deposited inside and below the exposure cylinder (30). FIG. 2 shows a state in which the capturing tool (40) is provided. FIG. 3 shows a state in which crystallized phosphorus is actually attached to the trap (40). In the case of the wire mesh catcher (40), crystallized phosphorus adheres to the mesh. The trapping device (40) only needs to be attached with crystals as a material, and the shape of the trapping device (40) is not limited to prevent the action of the exposure cylinder (30). Therefore, it may be a non-perforated plate that does not transmit sewage.

Furthermore, the invention according to claim 1 is provided with a crystallized product (precipitate / precipitate) on a member that comes into contact with livestock sewage that has undergone aeration treatment, in particular, the surface of the exposure cylinder (30) and the surface of the apparatus member including the treated water tank settling portion (12). It is characterized by the provision of a coating layer made of a crystal adhesion repellent material to which deposits are difficult to adhere. Specifically, the coating layer (16) is provided on the surface of the sedimentation part (12) at the bottom of the treated water tank, and the exposure cylinder. The surface of (30) is also provided with a coating layer (32).

  The entire exposed cylinder partition wall may be made of a crystal adhesion repellent material, and the surface of the precipitated portion and the exposed cylinder inner wall may be formed of a coating film of the crystal adhesion repellent material.

Furthermore, the present invention is composed of a material in which the trapping device (40) easily adheres to crystallized phosphorus in the sewage sewage after aeration treatment, and the outer shape is a water-permeable structure (42 ) Or an impervious non-porous plate-like material, and a device (44) for scraping off the attached crystallized material. 4 to 6 show examples of the water-permeable capturing tool (40). The catching tool (40) used in the present invention has the simplest structure as shown in FIG. Then, as shown in FIG. 5, the wire net can be provided with means (44) for scraping the crystallized product. Usually, those equipped with such crystallized material scraping means (44) are practical.

The amount of treated sewage when recovering phosphorus and the amount of phosphorus recovered vary depending on the phosphorus component in the sewage sewage, but the supply of sewage sewage per unit time, the amount of air blown by aeration, and the yield of crystallized products seem to be balanced. It is good to adjust appropriately.

  FIG. 6 is a collection tool for efficiently collecting crystallized materials by collecting a plurality of the simple structures shown in FIG.

In addition, the present invention , as a crystal repellent material, when immersed for one day and night (24 hours) (as defined below, immersed in a water depth of 0.2 to 0.8 meters for 1 to 50 days) A material having a crystal deposition amount per unit area of 8 milligram / square centimeter or less , preferably 5 milligram / square centimeter or less, particularly preferably 3 milligram / square centimeter or less is selected.
In other words, the crystal adhesion repellent material means a metal member such as stainless steel or aluminum having a smooth surface, or an organic material such as rubber, polyvinyl chloride, or polyacrylamide.
Moreover, Te present invention odor, wear is detachably provided comprising capturing device, depth 0.2 for 24 hours (immersion漬曝the cylinder at a predetermined depth, the conventional barns wastewater phosphorus content and sewage temperature conditions A material having a crystal deposition amount per unit area of 15 milligrams / square centimeter or more, preferably 20 milligrams / square centimeter or more when immersed in 0.8 meter for at least one day and night) is selected. Typical materials include metal members such as stainless steel, aluminum, and copper with scratches on the surface, and plastic materials such as polyvinyl chloride and polyacrylamide.

  Here, “slaughterhouse sewage” refers to sewage generated when raising livestock such as pigs, cows, and chickens. Specifically, it means a separated liquid after removing large solids by separating livestock manure, livestock washing water and a mixture thereof with a solid-liquid separator using a screen or the like.

  “Aeration” means that air is supplied to the wastewater to be treated to expel the gas containing carbon dioxide in the wastewater and replace it with air. In normal aeration treatment, it is assumed that ammonia nitrogen is oxidized by aerobic microorganisms (activated sludge). However, in the present invention, carbon dioxide in the sewage is removed and the pH is about 8-9. For example, it utilizes the fact that soluble phosphorus in sewage becomes an insoluble phosphorus compound.

  Therefore, the gas used for aeration is not limited to air, and it is not necessary to use many words as long as it is a “non-toxic” gas in sewage treatment regardless of the presence or absence of oxygen.

  When the sewage is basic, phosphorus is insolubilized and “precipitated” and “precipitated” as a “crystallized product”. The fine “precipitate” exists in a suspended state in the treated wastewater, but when the “precipitate” grows or aggregates, it precipitates to become “precipitate”. In the present invention, the term “crystallized product” is used for both precipitates floating in fine sewage and sediments precipitated in the sedimentation portion at the bottom of the treated water tank.

“Crystal adhesion repellent material” refers to a material to which a crystallized material such as MAP hardly adheres. In equipment related to sewage treatment, materials containing rubber are difficult to adhere to crystallized materials. It can be seen from experiments that it is difficult to adhere to a material whose surface is polished smoothly.
Here, the “crystal adhesion amount” is expressed as an adhesion weight (unit: gram / square centimeter ) per unit surface area when immersed in the sewage to be treated under predetermined conditions for at least one day and night (24 hours). Further, the surface area is an apparent portion of the immersed portion (immersion width × immersion depth).
In the present invention, the amount of adhesion is defined by setting the immersion time to 1 day (24 hours). Moreover, although the density | concentration of crystallized substances, such as MAP in livestock sewage, the water temperature of livestock sewage, etc. fluctuate a little throughout the season, the tendency of the surface material of the member which comprises a recovery device, and "crystal adhesion amount" does not change. According to the operation test of the demonstration experiment of phosphorus compound crystallization removal recovery from the National Institute of Agricultural Sciences, National Institute of Advanced Industrial Science and Technology, the actual sewage temperature is the year-round, extremely hot season (maximum water temperature 31 ° C; August 2002) ) And severe winter (minimum water temperature 8 ° C .; February 2003 ), the sewage temperature fluctuates greatly. However, it is observed that the crystallization of phosphorus causes good crystallization and crystallized substance adhesion even at this wide temperature range. Therefore, a sewage temperature range of about 17 to 23 ° C. is used as a temporary guide.

  On the contrary, MAP crystals adhere well to stainless steel rough plate, aluminum rough plate, polyvinyl chloride rough plate, polyacryl rough plate and lauan material whose surfaces are not finished smoothly.

The capturing tool is made of a material that easily adheres to the crystal. Further, this trapping device can be composed of a “water-permeable” article that can permeate aeration-treated sewage such as nets, straws, and cocoons, but it only needs to be dipped in the treated sewage, so that crystals can be attached, so it consists of a curved surface or a flat surface. Even a “non-permeable plate-like material through which treated sewage does not permeate” can serve as a catcher without hindrance.

By using the phosphorus recovery apparatus from sewage sewage according to the present invention, it is possible to suppress the adhesion of crystallized substances to the inner wall portion of the exposure cylinder, suppress the phenomenon of effective aeration volume in the exposure cylinder, and reduce the volume. It can be maintained for a long time. As a result, the removal efficiency of the crystallized product and the recovery of the precipitated product are high. In addition, if a trap with excellent crystal adhesion performance is suspended in the exposure cylinder, the phosphorus recovery efficiency can be further improved.

In summary, improving the recovery efficiency of the phosphorus compounds, smooth operation of the purification apparatus, it is possible to reduce the operating costs through reduced so maintenance costs associated with long-term operation.

<Embodiment of the Invention>
An apparatus for recovering phosphorus from sewage sewage includes an exposure cylinder provided for carrying out aeration inside the treated water tank, an introduction (supply) port for sewage sewage, a discharge (outlet) port for treated water, and an exposure cylinder. An air ejection means provided in the lower part (lower part) and an outlet for phosphorus-containing particles generated (precipitated) by insolubilization are provided. Of course, as a simple method, phosphorus compounds containing sewage (mixed sewage) is inserted from the top of the water tank into the hose (mixed sewage transport pipe) to the bottom of the water tank, and pumps (mixed sewage transport power) Pumping by means).

  Since the present invention is also intended for small-scale livestock farmers, the phosphorus recovery apparatus of the present invention does not need to be provided with pH adjusting agent addition means (including a pH measuring device) such as caustic soda. In addition to the addition means such as the above, even if such a pH adjuster addition means is provided, there is no problem in the operation and operation of the phosphorus recovery apparatus of the present invention.

  In the apparatus of the present invention, the entire surface of the treated water tank or at least the surface of the exposed cylinder inner wall and the surface of the lower sedimentation portion are formed or coated (coated) with a crystal adhesion repellent material. Examples of the material exhibiting the crystal adhesion repellent performance include a hydrophobic polymer (easy moldable plastics) material having a smooth surface. This material includes, for example, natural rubber and synthetic rubber that have been cross-linked and repaired to an ordinary degree, and ethylene-propylene (-butadiene) copolymer rubber. The crystal adhesion repellent material forms the entire precipitation portion, and can be attached to the surface like a decorative board, and a thin layer (coating film) may be formed by application. The thickness of the surface layer made of the crystal adhesion repellent material is sufficient to withstand damage and peeling.

  In the present invention, the material of the phosphorus recovery part that recovers phosphorus etc. by sinking in the exposure cylinder and depositing crystallized substance on the surface thereof can easily and sufficiently attach the crystallized substance such as MAP to the surface. If it is. Specifically, wood such as stainless steel or Lawan that can penetrate moisture can be used.

  The structure of this phosphorus recovery part only needs to have a portion to which a crystallized substance such as MAP can be attached. Since the person who actually uses the part is a livestock farmer, it is desirable to make it as light as possible. For this reason, it is recommended to use a stainless steel wire mesh. The hemp net also has excellent crystal adhesion performance, but the cleaning after recovering the crystallized material is troublesome and the workability is not as good as that of the stainless steel net.

  When a stainless steel wire mesh is used, the mesh opening of the wire mesh is not particularly limited as long as crystals can adhere, but a range of 3 mm to 15 mm is usually selected.

  Further, this phosphorus recovery part may be installed in any form as long as it is immersed in the treated sewage in the exposure cylinder, suspended from above the exposure cylinder, fixed to the inner wall of the exposure cylinder, etc. Can function.

  In addition, deposits, that is, crystallized substances, adhere to collecting tools (permeable containers) such as permeable ridges, nets, and colander (cold containers). To be. As a material to which a crystallized substance easily adheres, there is a material having durability such as stainless steel and having excellent deposit adherence, and can form a net or a ridge.

  The supplementary explanation of the present invention is as follows. In this recovery means, first, coarse filter means for removing coarse insoluble matter from wastewater is provided to remove coarse insoluble matter.

  Livestock sewage is introduced into the aeration tank, and the sewage is aerated through the air from the aeration holes. The carbon dioxide in the sewage is expelled by the ventilation and the pH of the sewage rises. In aeration only with air, the pH of sewage is at most about 9 (about 8.5 to 9 in actual results), and pH management is unnecessary throughout the operation. In other words, there is no problem even if left unattended.

  Next, as a recovery device, the generation of scales and measures to deal with them are extremely important. Basically, the recovery of phosphorus and phosphorus compounds is improved, and the scale remains in wastewater after wastewater treatment as much as possible. In order to prevent this, it is necessary to prevent the piping from becoming a scale obstacle (strainer clogging). It is desirable to increase the recovery efficiency. In this sense, the present invention is a very effective device.

  The present invention is an apparatus for providing an exposure cylinder inside a treated water tank, solidifying (crystallizing) soluble phosphorus in livestock sewage by aeration at the site, and recovering the precipitate. Recover the precipitated crystallized material by preventing the crystallized material from adhering to the inner wall of the exposed cylinder by covering the entire or part of the surface of the exposed cylinder with the crystal repellent material. It is a recovery device for phosphorus and the like from livestock sewage characterized by improving efficiency.

  Further, the present invention provides an exposure cylinder inside the precipitation tank, and solidifies (crystallizes) the soluble phosphorus in the barn sewage by aeration at the site, and crystallizes the entire exposure cylinder in an apparatus for recovering the precipitate. In addition to covering all or part of the surface of the exposed cylinder with the crystal repellent material, or part or all of the surface of the sedimentation tank in contact with the sewage sewage, the crystal repellent By forming or coating with a reactive material, the adherence of crystallized substances to the inner wall of the exposed cylinder is prevented, and in addition, the adhering of crystallized substances to the wall surface at the bottom of the treated water tank is prevented, and the precipitated crystallized substances are recovered. It is a recovery device for phosphorus or the like from barn sewage characterized by further improving efficiency.

  Furthermore, an aeration cylinder is provided inside the treatment water tank, and the aeration cylinder is used to solidify (crystallize) the soluble phosphorus in the sewage sewage to recover the precipitate. Or by covering all or part of the surface of the exposure cylinder with the crystal adhesion repellent material, and preventing the adherence of crystallized substances to the inner wall of the exposure cylinder, and aeration treated sewage in the exposure cylinder A recovery device comprising a means for sinking a recovery member (means) made of an easily crystallizable material and attaching a crystallized substance to the recovery member such as phosphorus and recovering the crystal; It is a collection device of phosphorus etc. from sewage sewage which can raise the adhesion collection efficiency of the crystallization thing in.

  Examination of the crystallized substance repellent material in the recovery apparatus is important in the present invention as described later in Examples 1 to 4.

  A non-adhesive material is coated as the material of the treated water tank sediment. In this case, a deposit accumulates in the treated water tank sediment. The material is typically a rubber-coated material, but is not limited to a rubber material, and any material that exhibits equivalent properties and performance can be applied.

  For searching for materials other than rubber, as described in detail in the examples, test pieces made of various materials are suspended in sewage that has undergone aeration treatment and immersed in the sewage. After a predetermined time, the surface of the test piece is observed. For example, the attached state of the crystallized material can be observed using the naked eye, a spectacle, a metal microscope, or the like. If a material that hardly adheres can be found, it is recognized that the material is suitable for the exposure cylinder material of the present invention. A material excellent in workability and durability can be selected from such materials. Not limited to aeration, etc., it is suitable as a coating material for pipes and treated water tank sediments.

  In order to increase the collection efficiency of the precipitated (crystallized) matter, a suspended aggregate collecting means (for example, a net or a bowl-like object) is disposed in the treatment water tank including the exposure cylinder, and after collecting an appropriate amount, the collecting means Aggregates (generally crystallized products) are collected. It is recommended that the collection means nets, bags, etc. be replaced for timely collection.

  Examples of the material to which the crystallized material adheres well include stainless steel for metal and lauan for wood. In this case as well, materials that adhere well can be selected by suspending various test pieces in aerated barn sewage, immersing them in the sewage, and observing the surface of the test piece after a predetermined time. Newly discovered materials can be used instead of stainless steel. Representative examples of collection objects are ridges and nets.

  Hereinafter, the present invention will be described in more detail with reference to examples.

<Example 1>
Sewage generated from a pig house in the National Institute of Agricultural Sciences, Livestock Pasture Research Institute (Tsukuba City, Ibaraki Prefecture), which was passed through a screen and used as “slaughter house sewage”. As an apparatus for crystallizing soluble phosphorus in barn sewage and recovering the precipitate, a processing guess in operation at the laboratory is 4 m ³ / day (supra; Techno Innovation, 45, 20-25, 2002) )It was used. The exposure cylinder in this device is submerged by 1.4 m.

表１に示すとおり、ゴムはステンレス鋼に較べ結晶の付着が極めて少なく、しかも長期間に亘り付着量が抑制されていることが判明した。
この発見に基づき、曝気筒全体をゴムのような結晶が付着し難い性質を持つ材料で成形するとよい。本発明ではこの結晶が付着し難い性質を持つ材料を「結晶付着忌避材料」と称することとする。曝気筒全体を成形する代わりに、畜舎汚水と接する曝気筒表面部分（内壁）をこの材料により被覆するか、又は結晶付着忌避材料を適切な溶媒に溶いて適当な厚さとなるように塗布して被膜を形成することによって、結晶化物の付着を相当量回避できることも明らかとなった。曝気筒における結晶化物の付着が少ないと、有効曝気容積が維持されるため結晶化物の沈澱回収の効率を維持できることが予測される。
＜実施例２＞
実施例１と同様の豚舎汚水を用い、また畜舎汚水中の溶解性リンを結晶化させ沈澱回収する装置を用いた。この実験では、曝気筒内にステンレス鋼（SUS304）製金属片及びラワン材木片を水深0.2〜0.8メートルの部分に沈め、それぞれの試験片の表面上に結晶が付着する状態ついて検討した。結晶付着の経時変化を表２に示した。

表２に示したとおり、程度の差こそあれ、ステンレス鋼、木材共にその表面に結晶が付着することが確認できた。これらの結晶は軽く擦るだけで容易に剥ぎ落とすことができた。また、得られた結晶を化学分析した結果、その固形分の大部分（約９４％）がＭＡＰであることが判明した。 The recovery device is almost entirely made of stainless steel (SUS304), including the exposed cylinder. The inner wall of the exposed cylinder is 3 millimeters thick at a depth of 0.2 to 0.8 meters in the exposed cylinder. The adhesion state of the crystals was observed for the case where the rubber sheet was used and the case where the exposed cylinder inner wall was made of stainless steel. The results are shown in Table 1.

As shown in Table 1, it has been found that rubber has very little crystal adhesion compared to stainless steel, and the adhesion amount is suppressed over a long period of time.
Based on this discovery, the entire exposed cylinder may be molded from a material that is difficult to adhere to crystals such as rubber. In the present invention, this material having the property that crystals are difficult to adhere is referred to as “crystal adhesion repellent material”. Instead of molding the entire exposure cylinder, the exposed cylinder surface part (inner wall) that contacts the barn sewage is covered with this material, or the crystal repellent material is dissolved in an appropriate solvent and applied to an appropriate thickness. It has also become clear that a considerable amount of crystallized material can be avoided by forming a film. If the amount of the crystallized substance adhering to the exposure cylinder is small, the effective aeration volume is maintained, so that it is predicted that the efficiency of the crystallized substance precipitation recovery can be maintained.
<Example 2>
The same piggery sewage as in Example 1 was used, and an apparatus for crystallizing soluble phosphorus in livestock sewage and recovering the precipitate was used. In this experiment, a metal piece made of stainless steel (SUS304) and a Lauan wood piece were submerged in a portion having a water depth of 0.2 to 0.8 meters in the exposure cylinder, and the state in which crystals adhered to the surface of each test piece was examined. Table 2 shows changes with time in crystal adhesion.

As shown in Table 2, it was confirmed that crystals adhere to the surface of both stainless steel and wood, to some extent. These crystals could be easily peeled off by light rubbing. Further, as a result of chemical analysis of the obtained crystal, it was found that most of the solid content (about 94%) was MAP .

表３に示したとおり、程度の差こそあれ、いずれの材料でも板表面全体に粗くキズをつけた試験片には、その表面にＭＡＰ等の結晶が付着することが確認できた。また、板表面が平滑な試験片の場合は、銅を除き、結晶の付着は少量であった。表面が軟らかい金属銅は表面キズがつきやすく、平滑な試験片を用いた場合でも曝気筒内に沈めているうちにキズが生じ、多くの結晶が付着したものと推測される。ゴムは滑面板群、粗面板群いずれでも結晶の付着量は最少であった。 <Example 3>
The same piggery sewage as in Example 1 was used, and an apparatus for crystallizing soluble phosphorus in the same barn sewage and recovering the precipitate was used.
A phosphorus recovery means (see Fig. 3a) that combines a wire mesh made of stainless steel (SUS304) wire (rectangle: 15 x 40 centimeters , mesh opening; 1.0 centimeter ) and a fixing angle was prototyped. The collected parts were submerged in the exposed cylinder at a depth of 0.3 to 0.7 meters , and the angled part was fixed to the exposed cylinder inner wall. Was pulled after submerged for 30 days, crystals 1.04 kilograms wire mesh portion was adhered (see FIG. 3 b). These crystals could be peeled off with only a slight impact. Chemical analysis of the obtained crystal showed that the portion that grew greatly as a crystallized product was almost MAP and contained less impurities, and the content of components other than MAP in the organic matter etc. was about 5% by weight before washing. %, About 1% by weight after washing with tap water.
<Example 4>
The same piggery sewage as in Example 1 was used, and an apparatus for crystallizing soluble phosphorus in livestock sewage and recovering the precipitate was used. In this experiment, a plurality of stainless steel (SUS304) metal plates, aluminum metal plates, copper metal plates, polyvinyl chloride plates, polyacrylamide plates and rubber plates each having a smooth surface were prepared and divided into two groups. . One group is as it is (smooth surface), the other group is a grindstone (coarse # 36, trade name "Safety Touch Super, No. 1", Fujiwara Sangyo Co., Ltd. (Miki City, Hyogo Prefecture) distributor) About the situation where the entire surface is roughly scratched (scratched), used as a rough surface plate, submerged in a 0.2 to 0.8 meter depth of water in the exposed cylinder for 34 days, and crystals adhere to the surface of each specimen. Examined. Table 3 shows the state of crystal adhesion.

As shown in Table 3, it was confirmed that crystals such as MAP adhered to the surface of the test piece, which was rough and scratched on the entire plate surface with any material. Further, in the case of a test piece having a smooth plate surface, the amount of crystals adhered was small except for copper. Metallic copper with a soft surface is easily scratched, and even when a smooth test piece is used, scratches are generated while submerged in the exposed cylinder, and it is assumed that many crystals are attached. The rubber had the least amount of crystals attached to both the smooth plate group and the rough plate group.

  The most important point in the present invention is a special advantage that the technique of the present invention can be easily applied even to a small-scale livestock farmer.

It is the schematic of the collection | recovery apparatus which collect | recovers phosphorus from the barn sewage which shows the Example of this invention. The entire exposed cylinder in the recovery device is formed of rubber, which is a crystal repellent material. It is the schematic of the collection | recovery apparatus which collect | recovers phosphorus from the barn sewage which shows one of the other Examples of this invention. A crystal adhesion repellent material is affixed to the inner wall of the exposure cylinder in the recovery device, rubber is stretched on the sedimented portion below the treated water layer, and a phosphorus recovery part that collects crystallized substances in the exposure cylinder is provided. It is suspended. FIG. 2 is a perspective view of a stainless steel wire mesh that can be used in the present invention, and an external view of a crystallized substance attached to the wire mesh. It is a schematic diagram of the stainless steel wire mesh used for this invention. 4A is a perspective view showing a planar wire mesh, and FIG. 4B is a perspective view showing a cylindrical wire mesh. FIG. 3 is an external view (perspective view) of a wire net with a member for scraping off a crystallized substance attached to the wire net. FIG. 5 is a perspective view of a phosphorus recovery member formed by assembling a plurality of single-layer metal meshes shown in FIG. 4.

Explanation of symbols

10 Treated water tank 12 Precipitation part 14 in the lower part of treated water tank Precipitate collection port 16 Precipitation part lining (crystal adhesion repellent material)
18 Precipitation deposited 20 Livestock sewage supply port 22 Livestock sewage introduction pipe 24 Livestock sewage outlet pipe 26 Livestock sewage supply source 28 Treated water drainage 30 Exposure cylinder 32 Exposure cylinder coating layer (crystal adhesion repellent material)
34 Aeration hole 36 Vent pipe 38 Air supply source
40 Precipitate Collection Tool 42 Stainless Steel Wire Mesh Precipitate Collection Tool 44 Attachment Tool for Scraping Adhering Crystalline 46 Adhering Crystallized Material

Claims (3)

A treated water tank for collecting and processing phosphorus in the sewage in the barn;
Livestock sewage introduction means for introducing the livestock sewage into the treated water tank;
An air diffuser for diffusing air or non-toxic gas into the livestock sewage;
An air distribution means for distributing air or non-toxic gas to the air diffusion means;
An aeration cylinder that is installed immediately above the aeration means and surrounds the sewage during the aeration process containing air bubbles formed by the aeration means inside the treatment water tank;
A phosphorus-containing precipitate recovery means for recovering the precipitated phosphorus-containing precipitate from the bottom of the treated water tank by precipitation and crystallization by aeration;
Capturing means for capturing crystallized phosphorus deposited in the barn sewage installed in at least one of the barn sewage inside and below the exposure cylinder;
A livestock sewage deriving means for deriving the livestock sewage after treatment from the treated water tank, and a phosphorus recovery device from livestock sewage,
The exposure cylinder and the bottom of the treatment water tank are made of a material having a daily deposition rate of crystallized phosphorus of 8 milligrams / square centimeter or less,
An apparatus for recovering phosphorus from barn sewage, wherein the capturing means is made of a material having a daily deposition rate of the crystallized phosphorus of 15 milligrams / square centimeter or more. The apparatus for recovering phosphorus from barn sewage according to claim 1, wherein the exposed cylinder and the bottom of the treated water tank are made of a smooth surface plate of stainless steel, polyvinyl chloride, polyacrylamide, or rubber. The apparatus for recovering phosphorus from barn sewage according to claim 1 or 2, wherein the trapping means comprises a rough surface plate of stainless steel, aluminum, copper, polyvinyl chloride, or polyacrylamide.

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