JPH11262763A - Sewage purifying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply remove phosphorus and nitrogen components in living waste water. SOLUTION: A sewage purifying apparatus 10 wherein a metal net container 4 having an air chamber 5 disposed in the bottom part thereof is packed with an ion exchange resin 9 is immersed in a sewage pit 1 and, when air is passed through the air chamber 5 from a pump 6, air becomes air bubbles to rise to whirl up the ion exchange resin 9. Therefore the contact area of the ion exchange resin 9 with waste water is expanded and ion exchange is smoothly performed. Since the sewage treatment apparatus is directly immersed in sewage, it is unnecessary to ensure a place for arranging the sewage purifying apparatus and, as a result, purifying treatment at a narrow place difficult to adapt the sewage purifying apparatus heretofore can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying sewage by removing phosphorus and nitrogen in sewage by a simple method and purifying the sewage without generating blue powder.

[0002]

2. Description of the Related Art Domestic wastewater and the like contain a large amount of phosphorus and nitrogen which are substances causing eutrophication. Is required. There are the following methods for removing phosphorus, but they have various problems in practical use.

[0003] The condensation method is a method utilizing a reaction of forming a poorly soluble salt by phosphorus and a metal. Therefore, since a relatively large amount of metal salt needs to be added, the amount of generated sludge increases, and there is a problem that the treatment is complicated.

[0004] The adsorption method is a method of purifying waste water by flowing it into a reaction tower or a tank filled with an adsorbent such as alumina, zirconia, magnesia, and anion exchange resin. But,
It is known that the selection of an adsorbent and the adjustment of an appropriate water flow rate are difficult, and the use results are small (Environment of Water Pollution Prevention Equipment, P162, March 28, 1995, first edition, company).

[0005] The crystallization method uses hydroxyapatite [C
a ₅ (OH) (PO ₄ ) ₃ ] or magnesium ammonium phosphate [Mg (NH ₄ ) PO ₄ ], which is a poorly soluble crystal seed. However, the time required for these crystalline materials to reach the dissolution equilibrium is too long, and during that time, the concentration of each ion in the solution tends to be supersaturated. In such a state, fine crystals are generated and sludge is formed, so that there is a problem that complicated operations such as addition of indeterminate ion species and pH adjustment are required.

[0006] The biochemical dephosphorization method is a method utilizing polyphosphate bacteria. However, since it must be maintained under anaerobic conditions, the apparatus becomes large-scale and the phosphorus removal ability is not sufficient. is there.

[0007] There are the following methods for removing nitrogen, but they have various problems in practical use.

[0008] The ammonia stripping method is a method for removing ammonia by increasing the pH to remove it, and is a method applied in the case of high concentration wastewater. However, it has a problem that it requires the treatment of volatile gas, and its use has been limited.

In the discontinuous chlorination method, hypochlorous acid and chlorine are added to an aqueous solution containing ammonia, and 2NH ₃ +
In this method, ammonia is removed by a reaction of 3Cl ₂ → N ₂ + 3HCl. This method is quick and simple in reaction, but has a problem that an expensive alkali is required for neutralizing the nitric acid and chlorine compounds since they are by-produced.

In the catalytic oxidation method, alumina, zirconia,
This is a method in which a catalyst such as platinum, ruthenium, or palladium supported on a carrier such as titania is heated to 250 to 300 ° C., sewage is passed under pressure, and decomposed into nitrogen gas and water. However, there are problems such as using at a high temperature and high pressure and deteriorating the catalyst when the concentration is low.

The selective ion exchange method is a method in which a cation resin and zeolite are used for removing ammonia. Although this method is simple, zeolite is affected by alkaline earth metals such as magnesium and calcium, and thus has a problem in that the quality of wastewater must be checked in advance.

[0012] Biological nitrogen removal has been successfully applied to sewage and various industrial wastewaters. However, an aerobic reaction requires a stirring tank, and the digestive bacteria are autotrophic bacteria and have a slow growth rate, so a large reaction tank is also required. In addition, a solid-liquid separation membrane is required in the reaction tank, and the membrane needs to be periodically replaced. Further, there is a problem that the membrane is not suitable for low-concentration drainage.

According to the present invention, wastewater such as domestic wastewater containing phosphorus and nitrogen can be rapidly purified by a simple method, and the total nitrogen is about 0.4 mg / day so as not to generate blue powder.
It is an object of the present invention to apply a sewage purification method for maintaining liter and phosphoric acid at about 0.03 mg / liter or less.

[0014]

The present inventors have focused on a method using an ion exchange resin as means for achieving the above object. As a method using this ion exchange resin, a method as shown in FIG. 8 is conventionally known. First, sewage is guided from a sewage pit 218 to a stainless steel or corrosion-resistant plastic container 217 by a pump 219, and water is passed from above while controlling the flow rate. The interior of the stainless steel or corrosion-resistant plastic container 217 is filled with an ion exchange resin, and the contaminated sewage is treated here and discharged as treated water 210 from below. In the case of such a method, usually, two towers of a strongly acidic resin and a strongly basic resin are required, and two sets of pumps and valves, and a filter 220 for removing suspended solids in the wastewater are also required. . In addition, there is a problem in that the apparatus must be installed in a place different from the sewage pit 218, and the place for installation and the cost for the installation are expensive.
Therefore, the present inventor has conducted studies to improve the conventional method using such an ion exchange resin, and as a result, a purifying apparatus capable of directly immersing the water to be treated in a sewage source in which the water to be treated is stored for purifying treatment. The present invention has been completed by finding out the use of the present invention.

According to the present invention, as a first aspect, a sewage purification apparatus filled with an ion exchange resin in a water-permeable container is immersed in the water to be treated, and the ion exchange resin in the sewage purification apparatus is at least from below. Provided is a sewage purification method characterized by applying an external force directed upward. The present invention also provides, as claim 2, the method for purifying sewage according to claim 1, wherein the water-permeable container is a container made of a wire mesh of 40 to 120 mesh or a plastic having equivalent pores. According to a third aspect of the present invention, there is provided a method in which the means for applying an external force directed at least upward from below to the ion exchange resin container in the sewage purification apparatus is ventilated at the bottom of the sewage purification apparatus. 2. A method for purifying sewage according to item 2. According to a fourth aspect of the present invention, there is provided a method according to the first or second aspect, wherein the means for applying at least an external force directed upward from below to the ion exchange resin in the sewage purification apparatus moves the sewage purification apparatus up and down. 2. A method for purifying sewage according to item 2.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for purifying sewage of the present invention will be described with reference to FIGS. FIG. 1 is a schematic sectional view of a sewage purification apparatus used in the present invention, and FIGS.
FIG. 1 is a schematic diagram for explaining a sewage purification method of the present invention.

As the sewage purification apparatus used in the present invention, there can be mentioned the one shown in FIG. The sewage purification apparatus 10 shown in FIG. 1 is obtained by filling a water-permeable container 4 with a required amount of ion exchange resin 9.

The water-permeable container 4 is capable of smoothly entering and leaving the inside of the container made of sewage from a main body made of metal, plastic, or the like. It has a plurality of holes enough to hold the resin 9 in the container. Such a water-permeable container 4
Suffices that at least a part is water-permeable. Therefore, in FIG. 1, the upper surface 4a or the lower surface 4b of the water-permeable container 4 may be water-permeable, and the side surface may be non-water-permeable, the side surface may be water-permeable, and the upper surface 4a or the lower surface 4b may be non-water-permeable. Is also good.

The upper surface 4a of the water-permeable container 4 can be opened depending on the condition of use, or can be a hole larger than other portions. By making the upper surface 4a open or larger, the small suspended solids that have passed through the holes of the water-permeable container 4 and entered the interior can be released from the upper surface 4a to the outside of the water-permeable container 4. Become like

The shape and size of the water-permeable container 4 can be appropriately changed according to the size of the wastewater source to be treated and the like, and can also be partially multi-layered. Examples of the water-permeable container 4 include a wire net made of about 40 to 120 mesh and a plastic one.

The ion exchange resin 9 has a particle size of about 30
Examples thereof include a porous or gel type strongly acidic cation exchange resin and a strongly basic anion exchange resin of 0 to 1180 μm.

The filling amount of the ion-exchange resin 9 into the water-permeable container 4 can be appropriately set according to the treatment state of the wastewater, etc., but in the present invention, the ion-exchange resin 9 is allowed to move to some extent by free movement. To secure and increase the contact area between the ion exchange resin 9 and the sewage, it is preferable to fill the ion exchange resin 9 in an amount of about 85% by volume or less based on the capacity of the water-permeable container 4.

In the method for purifying sewage of the present invention, an external force is applied to the ion-exchange resin in the sewage purification apparatus at least upward from below. By applying an external force at least upward from below in this way, for example,
In the sewage purification apparatus 10 shown in FIG. 1, the ion-exchange resin 9 soars in the water-permeable container 4 so as to dance, so that an interval is generated between the ion-exchange resins 9. As a result, the contact area between the sewage and the ion exchange resin 9 can be further increased, whereby PO ₄ , NO ₃ , NH ₄ ions, etc. in the sewage can be quickly exchanged with H, OH or Cl of the ion exchange resin. Then, it is adsorbed on the resin and is subjected to a smooth purification treatment. Therefore, the sewage and the ion exchange resin 9
As long as the contact area can be increased, the direction in which the external force is applied can be applied from below to above and further from any direction such as the vertical direction or the horizontal direction. The means for applying such an external force is not particularly limited, and may be appropriately selected according to the treatment state of the wastewater.

Next, an embodiment of the purification method of the present invention will be described with reference to FIG. In this method, as a means for applying an external force at least upward from below to the ion exchange resin, a method of aerating at the bottom of the sewage purification apparatus is applied.

Sewage flows from the drain pipe 2, and a sewage purification device 10 made of wire mesh is immersed in the stored sewage pit 1. At this time, the sewage purification device 10 may be immersed in the sewage so as to be submerged, or may be immersed so that the upper surface is higher than the sewage surface. The water-permeable container 4 of the sewage purification device 10 has a double-layered structure made of a wire mesh bottom, and is provided with an air chamber 5 that is kept impermeable except for the bottom side. Then, the air is pumped into the air chamber 5 through the pipe 7 by the air pump 6. Since this air flows upward from the bottom of the water-permeable container 4 as bubbles 5 a, an external force is applied to the ion exchange resin 9 from below to above. As a result, the ion-exchange resin 9 soars like a dance and the contact area with sewage is enlarged. Therefore, PO ₄ , NO ₃ , NH ₄ ions and the like in the sewage are converted into H,
It is easily exchanged with OH or Cl (that is, a purifying action is performed), and the concentrations of phosphorus and nitrogen in the wastewater rapidly decrease.
In this treatment, suspended solids such as garbage are transferred to the water-permeable container 4.
To prevent contact with the ion exchange resin 9.

Next, another embodiment of the purification method of the present invention will be described with reference to FIG. This method applies a method of moving a sewage purification device in a vertical direction as a means for applying an external force at least upward from below to an ion exchange resin. The sewage purification device 10 is immersed in the pit wastewater (FIG. 3A). This sewage purification device 1
0 is suspended by the hoisting machine 14 via the wire 16. Therefore, when the sewage purification device 10 is lowered downward from above during immersion, the sewage pressure 15 is mainly applied in the direction of the arrow, and the ion exchange resin 9 in the water-permeable container 4 soars like a dance. The contact area is enlarged. Therefore, PO ₄ , NO ₃ , NH ₄ ions and the like in the sewage are easily exchanged for H, OH or Cl of the ion exchange resin, and the phosphorus and nitrogen concentrations in the sewage in the water-permeable container 4 are rapidly reduced. Then, when the hoisting machine 14 is operated and the sewage purification device 10 is raised above the sewage level, purified water contained in the ion exchange resin 9 is dropped (FIG. 3 (b)). Hereinafter, by repeating this operation, the purifying action is continuously performed. In this treatment, suspended solids such as dust are blocked by the water-permeable container 4 and are prevented from coming into contact with the ion exchange resin 9. Further, the suspended solids attached to the water-permeable container 4 are removed by water flowing from the inside to the outside.

Next, another embodiment of the purification method of the present invention will be described with reference to FIG. This method applies a method of moving a sewage purification device in a vertical direction as a means for applying an external force at least upward from below to an ion exchange resin. The sewage purification device 10 of FIG.
The ion-exchange resin 9 is filled in a cylindrical or polygonal water-permeable container 4 having a shaft 11 at the center. On the sewage pit 101, a bridge structure 104 is installed, on which an external force applying means 108 is attached. The external force applying means 108 includes a shaft 105 that makes a circular motion by the operation of a motor, and a cam wheel 106 mounted coaxially with the shaft 105. The sewage purification device 10 is immersed in a sewage pit 101, and the shaft 11 of the water-permeable container 4 is connected to an external force applying means 108 via a belt 107. Therefore, by driving the external force applying means 108, an external force in the vertical direction is continuously applied to the sewage purification device 10 by the action of the rotation of the shaft 105 and the cam wheel 106, and the sewage purification operation is performed. .

Next, another embodiment of the purification method of the present invention will be described with reference to FIG. This method is a combination of two sewage purification devices to which a method of aerating at the bottom is applied as a means for applying an external force at least upward from below to the ion exchange resin. The ventilation method is the same as the method shown in FIG.

In the first pit 1, a sewage purifying apparatus 10a in which a container 4 made of wire mesh is filled with a strongly acidic cation exchange resin 9
Is immersed. In the second pit 21, a sewage purification apparatus 10b in which a strongly basic anion exchange resin 9 is filled in a wire netting container 4 is immersed. From the sewage flowing into the first pit 1, NH ₄ ions are removed by the sewage purification device 10 a and sent to the second pit 21. Then, the PO ₄ ion and the NO ₃ ion are removed by the sewage purification device 10b, and are discharged as purified water 22.

Next, another embodiment of the purification method of the present invention will be described with reference to FIG. This method is a combination of two sewage purification devices to which a method of moving the ion exchange resin in a vertical direction is applied as a means for applying an external force at least upward from below. Note that the method of moving in the vertical direction is in accordance with the method shown in FIG.

The first pit 1 is provided with a sewage purifying apparatus 10 a in which a wire netting container 4 is filled with a strongly acidic cation exchange resin 9.
Is immersed. In the second pit 21, a sewage purification apparatus 10b in which a strongly basic anion exchange resin 9 is filled in a wire netting container 4 is immersed. From the sewage flowing into the first pit 1, NH ₄ ions are removed by the sewage purification device 10 a and sent to the second pit 21. Then, the PO ₄ ion and the NO ₃ ion are removed by the sewage purification device 10b, and are discharged as purified water 22. The hoisting machine 23a
Adopts a cantilevered outrigger 24 as a winding means, and the hoisting machine 23b employs a belt drive 25 as a winding means. The drive source is not shown.

Next, another embodiment of the purification method of the present invention will be described with reference to FIG. A sewage purification device 10a is immersed in the first pit 1 into which sewage flows. In the sewage purifying apparatus 10a, a strongly acidic cation exchange resin 9 is filled in a water-permeable container 4 made of a wire mesh provided with an air chamber 5 (the upper surface is open). Air pump 31
The air blown into the air chamber 5 through the pipe 32 applies an external force from below to above to the ion exchange resin 9 in the sewage purification device, so that the strongly acidic cation exchange resin 9 soars like a dance. . As a result, the contact area between the sewage and the strongly acidic cation exchange resin 9 is increased, so that NH ₄ ions are easily ion-exchanged, adsorbed on the resin, and removed.

The primary treated water from which the NH ₄ ions have been removed flows into the second pit 30 through the communication pipe 36. The sewage purification device 10b is immersed in the second pit 30. The sewage purification device 10 b includes a strong basic ion exchange resin 3 inside a water-permeable container 34 having an air chamber 35.
9 are filled. The water-permeable container 34 has a cylindrical metal or plastic non-water-permeable side wall and an upper surface 34a thereof.
And a water-permeable (about 40 to 100 mesh) filter or strainer provided on the lower surface 34b. The primary treated water flowing through the communication pipe 36 is
It is supplied from 4a to the sewage purification device 10b and descends to the lower surface 34b side. At this time, PO ₄ and NO ₃ ions are ion-exchanged and adsorbed and removed by the resin, and the purified water is discharged from the drain pipe 43. In this process, the on-off valve 40
When air is blown into the air chamber 35 from the air pump 31 via the pipe 41 by appropriately operating the air, the air becomes bubbles and rises in the water-permeable container 34 (strongly basic ion exchange resin 39) filled with the primary treatment water. As a result, the primary treatment water overflows to the upper surface 34a, so that suspended solids and the like adhering to the upper surface 34a can be removed.

Next, another embodiment of the purification method of the present invention will be described with reference to FIG. This embodiment is suitable for application to a flow path having a small depth of water, and the water-permeable container 5
As 0, one having a relatively low height below this shallow water depth but having a certain length in the flow direction is used. The water-permeable container 50 includes a plurality of wire nets 51 at predetermined intervals (relatively narrow intervals) in the flow direction,
An air supply pipe 52 having a plurality of air blowing holes 52a on the peripheral surface is provided near the bottom. The ion-exchange resin 9 is disposed between the metal nets 51, 51. A strongly acidic one is provided between the metal nets 51, 51 disposed on the upstream side, and the metal nets 51, 51 disposed on the downstream side. It is preferable to dispose a strong basic substance between them. If the air supply pipe 52 is not provided, there is a possibility that the ion exchange resin 9 is washed away and is deposited on the wire net 51 arranged on the downstream side and solidified. However, according to the present embodiment, the air supply pipe 52 is As air flows from the bottom of the water-permeable container 50 upward as air bubbles from the air blowing hole 52a, an external force is applied to the ion exchange resin 9 from below to above. Therefore, the ion-exchange resin 9 soars like a dance, does not accumulate and harden on the wire mesh 51 located on the downstream side due to the flow of sewage, and the contact between the sewage and the ion-exchange resin 9 is ensured. Similarly, the concentration of phosphorus and nitrogen in sewage decreases rapidly.

In the purification method of the present invention, sewage purification devices having two or more shapes and sizes and different types of ion exchange resins can be appropriately combined. Further, different means for applying an external force can be employed for each sewage purification device. When two or more sewage purification devices are used, an external force may be applied to at least one device.

The method for purifying sewage of the present invention is based on the assumption that 250 liters of domestic wastewater is discharged per person per day.
The purification treatment can be effectively performed for the treatment of domestic wastewater of 5 to 2,000 people. Therefore, the sewage purification method of the present invention, a pit into which sewage flows, a pool, a fountain, a fire prevention tank,
It can be applied to non-stagnant water areas such as irrigation canals and rivers, in addition to stagnant water areas such as ponds and lakes.

[0037]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Example 1 Purification of sewage was performed by a method as shown in FIG. In about 9 liters of sewage (NH ₄ ion concentration about 10 ppm), 8
A sewage purification apparatus filled with 600 g of a porous strong acid cation exchange resin was immersed in a cylindrical container made of 0 mesh wire mesh for about 30 minutes. During the immersion, air was pumped from the air chamber at a flow rate of about 100 liter / sec using an air pump. As a result, N
The H ₄ ion concentration dropped from about 10 ppm to about 1 ppm.

Example 2 The procedure of Example 1 was repeated, except that the porous strongly acidic cation exchange resin was replaced by a porous strongly basic anion exchange resin. As a result, PO in sewage
_{4 The} ion concentration drops from about 10 ppm to about 0.2 ppm,
The O ₃ ion concentration dropped from about 1 ppm to about 0.1 ppm.

Example 3 Sewage was purified by the method shown in FIG. In about 9 liters of sewage (NH ₄ ion concentration about 10 ppm), 8
A sewage purification device filled with 600 g of a porous strong acid cation exchange resin was immersed in a cylindrical container made of a 0 mesh wire mesh.
During the immersion, the sewage purification apparatus was moved up and down 120 times at intervals of about 30 seconds (the states of (a) and (b) in FIG. 3 were repeated). As a result, the NH ₄ ion concentration was reduced from about 10 ppm to about 0.7 ppm.

Example 4 The procedure of Example 3 was repeated, except that the porous strongly acidic cation exchange resin was replaced by a porous strongly basic anion exchange resin. As a result, PO in sewage
_{4 The} ion concentration decreases from about 10 ppm to about 0.5 ppm,
The O ₃ ion concentration dropped from about 1 ppm to about 0.1 ppm.

[0042]

The sewage purification method of the present invention can remove phosphorus and nitrogen in sewage by a simple method. Further, the sewage purification method of the present invention is a method in which the sewage purification device is directly immersed in the sewage, so that it is not necessary to secure a place for installing the sewage purification device, and it has been conventionally difficult to apply. In addition to being able to perform purification treatment in a narrow place, the installation cost and maintenance cost of the device can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a sewage purification device used in the present invention.

FIG. 2 is a schematic diagram for explaining an embodiment of a sewage purification method of the present invention.

FIG. 3 is a schematic diagram for explaining an embodiment of a sewage purification method of the present invention.

FIG. 4 is a schematic diagram for explaining an embodiment of a sewage purification method of the present invention.

FIG. 5 is a schematic diagram for explaining an embodiment of a sewage purification method of the present invention.

FIG. 6 is a schematic diagram for explaining an embodiment of a sewage purification method of the present invention.

FIG. 7 is a schematic diagram for explaining an embodiment of a sewage purification method of the present invention.

FIG. 8 is a schematic diagram for explaining an embodiment of a sewage purification method of the present invention.

FIG. 9 is a schematic diagram for explaining a conventional sewage purification method.

[Explanation of symbols]

 4 Water-permeable container 5 Air chamber 9 Ion exchange resin 10 Sewage purification device

Claims (4)

[Claims] 1. A sewage purification apparatus in which a water-permeable container is filled with an ion-exchange resin is immersed in the water to be treated, and an external force is applied to the ion-exchange resin in the sewage purification apparatus at least upward from below. A sewage purification method characterized by the following. 2. The sewage purification method according to claim 1, wherein the water-permeable container is a container made of a wire mesh of 40 to 120 mesh or a plastic having equivalent pores. 3. The sewage purification method according to claim 1, wherein the means for applying an external force at least upward from below to the ion exchange resin in the sewage purification apparatus is a method of ventilating at the bottom of the sewage purification apparatus. 4. The sewage purification method according to claim 1, wherein the means for applying an external force at least upward from below to the ion exchange resin in the sewage purification apparatus is a method of moving the sewage purification apparatus in a vertical direction. .