JPH11309449A - Phosphorus adsorbent, and method for removing phosphorus in natural environmental water area - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phosphorus adsorbent high in phosphorus adsorbing rate and continuing long in durabity without being clogged by turbid matter even if the quantity of the turbid matter of rivers increases, and to provide a rational phosphorus removing method easy installation. SOLUTION: This phosphorus adsorbent 8 is formed by sticking phosphorus adsorbing fine particles to a string-shaped member by holding action and adhesive action of gel like material. The gel like material for sticking the phosphorus adsorbing fine particles to the string-shaped member is preferably a gel whose solid phase component is alginic acid. In this phosphorus removing method, the dephosphorizing material is hung in water in the natural environmental water area such as rivers and lakes and marshes to adsorb and remove phosphate ions in water. The phosphorus adsorbent 8 can be hung in the river inflow part of lakes and marshes. The phosphorus adsorbent 8 is hung in water of lakes and marshes, aeration is performed from below the phosphorus adsorbent, and a water flow generated by the aeration is preferably contacted with the phosphorus adsorbent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel phosphorus adsorbent capable of easily and effectively removing phosphorus present in water in natural environmental waters such as rivers and lakes, and a natural environmental water using the same. And a method for removing phosphorus.

[0002]

2. Description of the Related Art In order to prevent eutrophication of rivers, lakes and marshes into which rivers flow, dam lakes, and the like, attempts have been made in recent years to remove phosphorus contained in river water. Typical phenomena associated with eutrophication include the occurrence of blue-green algae and red tide.
It is known that when the amount is over mg / liter, it is very likely to occur.

[0003] As a conventional method for removing phosphorus in river water, a large-particle-size particulate dephosphorizing material (for example, activated alumina, a phosphorus-adsorbing material such as Kanuma soil or allophane, etc., is burned into particles having a particle size of several centimeters, Attempts have been made to install a filling section filled with a molded particulate phosphorus adsorbent) in a river and to allow the entire amount of river water to flow into the particulate dephosphorizing material filling section to adsorb and remove phosphorus. This method can perform relatively effective adsorption and removal of phosphorus when the turbidity of the river is small, but has the following problems.

[0004] When the turbid mass of a river increases in rainy weather, the dephosphorization material-filled portion is likely to be blocked by turbidity. In order to prevent dephosphorization material from flowing out due to the increase in river flow in rainy weather and to reduce blockage due to SS,
The particle size of the dephosphorizing material is increased. For this reason, the specific surface area of the dephosphorizing material is small, and therefore the phosphorus adsorption speed is low. For this reason, the intended removal of phosphorus cannot be achieved unless a large amount of dephosphorizing material is filled in the river and the contact time between the river water and the dephosphorizing material is increased to 2 hours or more. When using the granular dephosphorizing material for the reasons described above, the amount of the dephosphorizing material used increases, the manufacturing equipment for supplying the dephosphorizing material becomes expensive, and the cost of transporting and filling the dephosphorizing material is also increased. Will also be higher. It is difficult to dispose of a large amount of waste phosphorus-removing material in which the amount of phosphorus absorbed has reached saturation, and replacing the waste phosphorus-removing material with a new phosphorus-removing material is also a large-scale operation. It is difficult to reduce the phosphorus concentration in the river water after passing the laid phosphorus removing material to 0.03 mg / liter or less using the current granular phosphorus removing material. The reason for this is that the specific surface area is small because the particle diameter of the particulate dephosphorizing material is as large as about 3 to 4 cm, and the phosphorus adsorption speed is low.

A method of removing phosphorus in water without using such a particulate dephosphorizing material has also been studied, and although there is no concrete example so far, the following method is in principle. Conceivable. That is, a coagulation sedimentation device is installed on land on the side of a river or lake, pumping up the entire amount of river water, adding an inorganic coagulant such as a sulfate band to coagulate phosphorus, and then sedimenting and separating the generated floc. A method is conceivable. However, this method has the following disadvantages and is not a good solution. A coagulating sedimentation apparatus requiring a large installation area must be installed on land, and the required installation area and construction costs for that are large. In addition, in rivers deep in the mountains, it is often impossible to secure a flat and wide installation place. Requires large-capacity pump and large power cost. Also,
Piping costs are also high. The disposal of coagulated sediment sludge is a challenge.

[0006]

DISCLOSURE OF THE INVENTION The present invention can solve all the drawbacks of the above-mentioned prior art, and can remove phosphorus in water in natural environment waters such as rivers and lakes in a very rational and simple manner. The purpose is to provide materials and to provide new technologies for phosphorus removal. That is, it is an object of the present invention to provide a technique capable of rationally removing phosphorus without having to fill a river with a large amount of particulate dephosphorizing material and without having to install expensive equipment such as a coagulation sedimentation apparatus. Specifically, as a dephosphorizing material to be used, the phosphorus adsorption speed is high, and even if the turbid mass of the river increases, the dephosphorizing material filling portion is not clogged with turbidity, and is an ideal material that lasts a long time. It is an object of the present invention to provide a method for removing phosphorus in rivers by obtaining a suitable dephosphorizing material and using it in a very rational and simple manner.

[0007]

Means for Solving the Problems The present inventor has conducted intensive studies on the development of a new dephosphorizing material and the method of using the same. By adhering to the surface, it is possible to provide an ideal dephosphorizing material that is durable and will not be blocked by turbidity in the river. The present inventors have found the optimum conditions for phosphorus removal and have reached the present invention.

[0008] The above object of the present invention is achieved by the following phosphorus adsorbent and phosphorus removal method. (1) A phosphorus-adsorbing material characterized in that phosphorus-adsorbing fine particles are attached to a string-shaped member by holding and adhering a gel-like substance. (2) The phosphorus adsorbent according to the above (1), wherein the gel-like substance for attaching the phosphorus-adsorbing fine particles to the string-like member is a gel containing alginic acid as a solid component. (3) The natural environment, wherein the phosphorus adsorbent according to the above (1) or (2) is suspended in water in a natural environment water area such as a river or a lake, and phosphate ions in the water are absorbed and removed. How to remove phosphorus from water. (4) At the river inflow of a lake, the phosphorus adsorbent according to the above item (1) or (2) is suspended in water, and the inflowing river water is brought into contact with the phosphorus adsorbent, and phosphate ions in the river water are removed. A method for removing phosphorus from natural environmental waters, comprising removing and adsorbing water. (5) Suspending the phosphorus adsorbent according to the above item (1) or (2) in the water of the lake, aerating from the lower part of the phosphorus adsorbent, and bringing the water flow having a large flow velocity into contact with the phosphorus adsorbent. Characteristic method for removing phosphorus from natural environmental waters. It is.

The present invention will be described more specifically with reference to the drawings. FIGS. 1A and 1B show examples of a cord-like member suitable for the present invention. The string-shaped member 1 shown in FIG. 1A is a string-shaped member knitted in a molding shape. The rope 2 serving as the axis of the string-like member 1 and the thread (loop-like thread) 3 of the loop portion which is floated and woven in a loop shape from the rope 2 may be a rope or a thread to which phosphorus-adsorbing fine particles are attached. In addition, thread 3 of the loop
Phosphorus-adsorbing fine particles may be attached only to these. The string-like member 4 shown in FIG. 1 (b) is a string-like member woven in a velvet shape. Rope 5 which is the axis of the string-shaped member 4
Further, the yarn 6 implanted therein may be a rope or a yarn to which phosphorus-adsorbing fine particles are attached, or the phosphorus-adsorbing fine particles may be attached only to the implanted yarn 6.

[0010] The phosphorus adsorbent of the present invention is not limited to the phosphorus adsorbent from the cord-shaped member knitted in a molding shape or the string-shaped member knitted in a belt shape. Any string-shaped member may be used as a carrier for the phosphorus-adsorbing material as long as the obtained string-shaped member has flexibility and a large surface area per unit volume of the phosphorus-adsorbing material. Fig. 2 shows the case of removing phosphorus from lake water.
String-like phosphorus adsorbent 8 using the above-mentioned bill-like string-like member as a carrier
It is explanatory drawing which shows an example which arrange | positions in a lake. There is no particular limitation on the location where the water is placed, but a portion where the river water flows into the lake is preferred. As shown in FIG. 2, a plurality of string-like phosphorus adsorbents 8 using a belt-like string-like member provided with a float 10 as a carrier are suspended from the lake surface.

The gist of the present invention is: 1) To provide a phosphorus adsorbent which is flexible and has a large surface area per unit volume by using a string-shaped member having a large specific surface area as a carrier of the phosphorus adsorbing fine particles. 2) By using the novel phosphorus adsorbent and applying the phosphorus removal method of the present invention, it is simple and even if the turbid mass of a river increases, the dephosphorizing material filling portion is blocked by the turbid substance. Able to remove phosphorus from water while maintaining high efficiency for a long time. There are two points.

The dephosphorizing material of the present invention comprises: a) a flexible string-shaped member having a large specific surface area as a carrier; and b) an adhesive action between the surface of the string-shaped member and the gel-like substance and retention of the gel-like substance. By holding the phosphorus-adsorbing fine particles on the surface of the string-like member through the action of the gel, c) the carrier can firmly hold the fine particles in the surface layer thereof while maintaining its flexibility. The phosphorus adsorbent of the present invention having such features is a completely novel phosphorus adsorbent, and is far superior to the conventionally known phosphorus adsorbent. Thus, by suspending this excellent novel phosphorus adsorbent in the water of natural environment waters by the method of the present invention, and optionally using an aeration device, it is possible to increase the turbid mass of the river for the first time. In addition, the phosphorus removal material filling portion is not blocked by turbidity, and effective phosphorus removal is possible without replacing the phosphorus removal material for a long period of time. Here, even if the turbid mass of the river increases, the turbidity does not accumulate in the installation part of the string-shaped and flexible dephosphorizing material because the turbidity does not accumulate in the algae colony portion in the river. It is presumed to be due to the same mechanism as described above.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The thread-like member used for molding the cord-like member of the present invention includes yarns from natural fibers such as cotton, silk and wool, polyvinyl chloride, polyvinylidene chloride, and the like.
Threads spun from synthetic fibers of polyacrylonitrile, polyvinyl alcohol, polyester, vinyl compound copolymer, condensation polymer of bifunctional ester or amide compound, etc. can be used arbitrarily. In order to allow the phosphorus-adsorbing fine particles to adhere to these thread-like members by the adhesive action of the gel-like substance, the surface of the thread is appropriately modified (for example, modified to a hydrophilic surface by a glow discharge treatment) by appropriately performing surface modification. Can be As the phosphorus-adsorbing fine particles, iron hydroxide, iron oxide, aluminum hydroxide, aluminum oxide, allophane, Kanuma earth, activated alumina, zirconium oxide, phosphorus ore, bone charcoal, etc. can be used. Fine particles of Kanuma soil are inexpensive and most suitable for the present invention.

In the present invention, it is convenient to use various hydrophilic gels to adhere the phosphorus-adsorbing fine particles to the string-like member formed from the thread-like member. The hydrophilic gel contains phosphorus in addition to being able to adhere the phosphorus-adsorbing fine particles to the string-shaped member due to its fine particle holding action and adhesiveness to the carrier, and the gel contains air bubbles therein so that it contains phosphorus. It has the desirable property that water can be quickly permeated. The hydrophilic gel is formed by causing a gelling agent to act on an aqueous solution of a hydrophilic polymer to cause gelation. In the present invention, a method of attaching the phosphorus-adsorbing fine particles to the surface of the string-shaped member will be described. First, a phosphorus-adsorbing fine particle dispersion is prepared by dispersing the phosphorus-adsorbing fine particles in an aqueous solution of a hydrophilic polymer. Then, the obtained phosphorus-adsorbing fine particle dispersion is applied to the surface of a string-shaped member formed from a thread-like member or the like,
Alternatively, the string-shaped member is immersed in the phosphorus-adsorbing fine particle dispersion and pulled up to form a sol layer on the member surface,
The sol layer on the surface of the string-like member is caused to act on a gelling agent to gel. An operation of forming a sol layer by applying an aqueous solution of a hydrophilic polymer in which phosphorus-adsorbing fine particles are dispersed on the surface of the string-shaped member, and bringing the sol layer on the member surface into contact with a gelling agent to gel. Is performed only once, when the amount of adhered gel is small, the same operation can be repeated a plurality of times to increase the amount of adhered gel and, consequently, increase the phosphorus adsorption capacity.

Preferred hydrophilic polymers include polyvinyl alcohol, polyacrylamide, sodium alginate, polyacrylate, and water-soluble polyurethane. In the present invention, the concentration of the aqueous hydrophilic polymer solution is preferably 0.5% to 2%. The concentration of the phosphorus-adsorbing fine particles in the phosphorus-adsorbing fine particle dispersion is preferably 1% to 5%. The higher the concentration of the phosphorus-adsorbing fine particles in the dispersion, the better the permeability of water into the gel and the better the phosphorus removal efficiency, but the poorer the retention of the phosphorus-adsorbing fine particles.

In the present invention, the case where sodium alginate is used as the hydrophilic polymer will be described in more detail. Phosphorus-adsorbing fine particles are dispersed in an aqueous solution of sodium alginate, and the thread-like member or a string-like member formed from the thread-like member is immersed in the aqueous dispersion. When the thread-like member or the string-like member is pulled up from the aqueous solution and the thread-like member or the string-like member to which the phosphorus-adsorbing fine particle dispersion liquid is attached is brought into contact with a calcium chloride aqueous solution (gelling agent), the calcium alginate gel becomes the thread-like member or the string-like member. Formed on the surface. When an aqueous ferric chloride solution or an aqueous aluminum sulfate solution is used as the gelling agent, an iron alginate gel or an aluminum alginate gel is formed on the surface of the thread-like member or the string-like member. These alginate gel membranes are coated with an aqueous solution of a phosphorus-adsorbing fine particle from a hydrophilic polymer aqueous solution other than the sodium alginate aqueous solution, and are more porous than the gelled gel membrane and into the phosphate ion gel layer. Therefore, the phosphorus-adsorbing fine particles fixed inside the gel can be effectively used. Therefore, in the present invention, a gel utilizing alginic acid is optimal.

As described above, the string-like member (the string-like phosphorus adsorbing material 8 shown in FIG. 2) on which the gel layer is immobilized has an excellent phosphate ion-absorbing ability, and as shown in FIG. Phosphorus is quickly adsorbed when it comes into contact with water 11 in lakes and rivers containing acid ions. Since the water flow is extremely small in lakes and marshes, simply attaching the float 10 to the string-shaped phosphorus adsorbent 8 and floating the float 10 on the surface of the water and suspending the string-shaped phosphorus adsorbent 8 in the water will cause adsorption of the phosphorus-containing water. Since the contact effect with the material is poor and the phosphorus adsorption speed decreases, the aeration trachea 9 is installed below the string-like phosphorus adsorbent 8 in order to increase the contact efficiency between the phosphorus-containing water 11 and the string-like phosphorus adsorbent 8. In a preferred embodiment, the air 7 is aerated from the aeration trachea 9 into water to generate an aerated water flow. However, it is not necessary to increase the aeration intensity, and aeration sufficient to generate a weak water flow is sufficient. The installation interval of the string-shaped phosphorus adsorbing material 8 suspended in water is an important factor, and if it is too narrow, the gap is closed by earth and sand, leaves of trees, and the like, and the string-shaped phosphorus adsorbing material is also closed. . However, if the installation interval is too wide, the phosphorus adsorption effect decreases. According to the test results of the inventor, the distance between adjacent string-shaped phosphorus adsorbents is 50 to 100 mm.
The case of the degree was an appropriate installation interval.

When a river flows into a lake and the river water contains phosphorus, as shown in FIG.
A position 13 with a water depth of about 0.5 m or more, slightly upstream of the river inflow portion 15 of 4 or the inflow portion of the river 12 into the lake 14.
When the string-shaped phosphorus adsorbent of the present invention is suspended, phosphorus in a river is adsorbed and removed, and the load of phosphorus flowing into a lake can be significantly reduced. Further, since the contact effect between water and the phosphorus adsorbent is improved by the flow velocity of the river itself, it is not necessary to perform aeration from below the phosphorus adsorbent, which is also advantageous from this point.

[0019]

EXAMPLES Hereinafter, the method for removing phosphorus from phosphorus-containing water and the phosphorus-adsorbing material of the present invention will be described in detail with reference to examples. However, the present invention is not limited by the following examples.

Example 1 (Fixation of Gel Layer Containing Phosphorus-Adsorbing Fine Particles on String-like Member) A mall-like string (trade name, Biocode, manufactured by TBR Co., Ltd.) was added to a 2% aqueous sodium alginate aqueous solution of iron hydroxide. The particles were immersed in a dispersion in which the fine particles were dispersed to a solid concentration of 3%, and the laces were pulled out of the dispersion and immediately immersed in a 2% calcium chloride aqueous solution. The fine particle-containing calcium alginate gel was immobilized. The amount of immobilization was 153 g (swelled gel) per 1 m of the string.

Example 2 (Phosphorus removal test) Using the phosphorus adsorbent prepared in Example 1, kaolin clay was dispersed in 100 mg / liter tap water, and the tap water was assumed to be turbid river water. A phosphorus removal test was performed. The test device is 20cm in diameter,
A cylindrical column having a depth of 1 m was used. In the phosphorus removal test, raw water (the kaolin-containing tap water having a phosphorus concentration of 0.1 mg / liter) was brought into contact with the phosphorus adsorbent (total length of 0.9 m) in the cylindrical column with a residence time of 30 minutes with a residence time of 30 minutes. I let go while passing. As a result, in the case of using the string-shaped phosphorus adsorbent, the phosphorus concentration of the treated water was reduced to 0.015 mg / liter. Further, under these conditions, the concentration of phosphorus in the treated water after passing water for 3 months was 0.018 mg / liter. Further, the phosphorus concentration of the treated water after passing water for 3 months (for 6 months) is 0.03.
It was 8 mg / liter and exhibited a long-term phosphorus removal ability. Further, no clogging of the phosphorus adsorbent with the kaolin SS particles was observed. Note that the phosphorus adsorption effect of kaolin itself was so small as to be negligible.

[0022]

Advantages of the Invention When the SS of the river increases, unlike the conventional method of passing river water through the packed layer of granular dephosphorizing material, the phosphorus-adsorbing fine particles adhere to the string-shaped member of the present invention by the action of holding and adhering the gel-like substance. In the case of the phosphorus adsorbent, the phosphorus adsorbent is not blocked by the SS because the gap for laying the phosphorus removal material is wide and the string-shaped member has a flexible structure. 2. Since the phosphorus adsorbent made of the string-shaped member of the present invention simply suspends the phosphorus adsorbent in the water of a river or lake, the installation work of the phosphorus adsorbent is simple. 3. Since the gel has good water permeability, the phosphorus removal rate is high and the phosphorus removal rate is high. 4. Since the phosphorus-adsorbing fine particles are firmly fixed to the string-shaped member, the life of the phosphorus-adsorbing material is long.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of the structure of a string-shaped member. (A) is a figure which shows the structure of a mall-shaped string-shaped member, and (b) is a figure which shows the example of a structure of a belt-shaped string-shaped member.

FIG. 2 is an explanatory diagram showing an example of an arrangement of a string-shaped phosphorus adsorbent in water and an arrangement of an aeration device.

FIG. 3 is an explanatory diagram showing an example of an installation position of a string-shaped phosphorus adsorbent in a natural environment water area.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 String-like member 2 Rope 3 Loop-like thread 4 String-like member 5 Rope 6 Thread 7 Air 8 String-like phosphorus adsorbing material 9 Aeration trachea 10 Float 11 Water 12 River 13 String-like phosphorus adsorbing material installation position 14 Lake / marsh 15 River inflow Department

Claims (5)

[Claims] 1. A phosphorus-adsorbing material characterized in that phosphorus-adsorbing fine particles are attached to a string-shaped member by a holding action and an adhesive action of a gel-like substance. 2. The phosphorus adsorbent according to claim 1, wherein the gel-like substance for attaching the phosphorus-adsorbing fine particles to the string-like member is a gel containing alginic acid as a solid component. 3. A natural environment water area wherein the phosphorus adsorbent according to claim 1 or 2 is suspended in water in a natural environment water area such as a river or a lake, and phosphate ions in the water are adsorbed and removed. Phosphorus removal method. 4. The phosphorus adsorbent according to claim 1 or 2 is suspended in water at a river inflow portion of a lake, and the inflowing river water is brought into contact with the phosphorus adsorbent to remove phosphate ions in the river water. A method for removing phosphorus from a natural environment water body, comprising removing by adsorption. 5. The method according to claim 1, wherein the phosphorus adsorbent according to claim 1 or 2 is suspended in the water of a lake and aerated from a lower portion of the phosphorus adsorbent, and the water flow generated by the aeration is brought into contact with the phosphorus adsorbent. Characteristic method for removing phosphorus from natural environmental waters.