JPH09215989A - Water treatment installation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a smaller scale biological decomposition installation by constituting the installation of a magnesium ion feeding apparatus wherein water within the water region where eutrophication advances is brought into contact with a magnesium ion feeding agent and a biological decomposition processing apparatus consisting of a tank wherein a braid-like contacting material is immersed. SOLUTION: A biological decomposition processing tank 3 in a processing apparatus for processing water within the water region where eutrophication advances is filled with a braid-like contacting material and changes org. substances into inorg. state by utilizing microorganisms and eliminates algae generated in the water region by means of an ultraviolet irradiation apparatus. In addition, a magnesium ion feeding apparatus 4 for bringing a magnesium ion feeding agent into contact with the water within the water region is assembled on the inside or the outside of the biological decomposition processing tank 3 and phosphorus in inorg. state after org. substances are decomposed is made into a hardly soluble compd. and is immobilized and eliminated. It is possible thereby to make a biological decomposition installation smaller in scale.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water treatment device for purifying water in a eutrophic water area.

[0002]

2. Description of the Related Art In recent years, in closed water areas such as lakes and marshes, which have large pollution sources in the hinterland, eutrophication has progressed due to the large inflowing pollutant load and the accumulation of pollutants. It has become a serious social problem such as the occurrence of abnormalities. In lakes and marshes of tourist destinations, the value of tourist resources is decreasing due to the damage of the landscape caused by the abnormal occurrence of microalgae due to the progress of eutrophication, and the presence of a strange odor.
The deterioration of the landscape due to the abnormal occurrence of microalgae in the ponds arranged in public facilities such as parks reduces the value of the rest space, which is important in cities, and in lakes that are the intake source of drinking water. Also, due to the abnormal occurrence of microalgae and freshwater red tide, problems of filtration problems and offensive odors of water supply facilities have occurred.
For this reason, the Water Pollution Control Act, the Lake Water Quality Special Measures Act,
Wastewater regulations for nitrogen and phosphorus related to lakes have been established and implemented.

[0003]

[Means for solving and using the invention] As main measures against these problems, (1) prevent the inflow of pollutants containing nutrient salts,
(2) Methods such as removing the bottom mud of eutrophic closed water areas, (3) purifying the eutrophication of water quality, and directly removing microalgae etc. grown by eutrophication have been proposed. . Of these, (1) cannot be completely implemented at this time because it can be achieved only by suspending or suppressing all production activities, including humans. As for (2), it is difficult to carry out the treatment of dredging and the remaining soil because of the huge cost and the large number of target lakes. Therefore, at this point, the direct water purification and algae removal measures of (3) are considered to be the most practical methods that can be put into practice. Direct filtration method, biodegradation method, and ultraviolet irradiation method are effective methods for removing microalgae already generated by eutrophication of lakes.

Among these direct removal methods, the direct filtration method is a method of filtering water in a water area with sand or the like, and since the clogging is severe, the filtering effect sharply decreases, and in a large-scale lake or marsh. There are drawbacks that cannot be applied. The biodegradation method of is effective for temporary removal, but it is impossible to control its generation. This is because nutrient salts that have been decomposed and mineralized by the biological method again cause the generation. In addition, in order to obtain a large effect of decomposition and removal with the equipment and devices that have been conventionally used, the equipment becomes large, which causes problems in practical use in terms of appearance and cost. The ultraviolet irradiation method is a method of maintaining the appearance of lakes by irradiating algae with ultraviolet rays to kill algae. At present, it is considered to be the most effective method, but it has a drawback that the running cost of ultraviolet irradiation is high. Therefore, implementing water purification measures only by these methods has problems in terms of cost and effects after implementation.

Therefore, as a result of diligent research, the inventors of the present invention focused on the behavior of phosphorus, which is indispensable for the growth of plants in water bodies where eutrophication is progressing. The amount of organic phosphorus produced is higher than that of inorganic phosphorus, and the conventional biodegradation method is due to the mineralization of organic matter using microorganisms.
Inorganic phosphorus becomes a nutrient source for algae growth again, most of the phosphorus that can be adsorbed and removed with an inorganic adsorbent is inorganic phosphorus, and ultraviolet irradiation is the main purpose of algae killing,
The formation of sparingly soluble compounds by the addition of conventional lime-based materials, which does not affect the amount of phosphorus present in the water, causes lime to react with carbon dioxide in the water and be coated with a film of calcium carbonate, resulting in long-term By discovering the fact that it is impossible to exert the effect over the whole time, the inventors have invented this device, which takes into consideration the reduction of phosphorus, which is indispensable for the growth of microalgae.

In order to reduce phosphorus in water bodies, it is important that reduction of inflow phosphorus and reduction of phosphorus in water bodies are carried out at the same time. However, it is difficult to reduce the inflowing phosphorus at this point for the reasons described above, so it is necessary to deal with it by reducing the inflowing phosphorus. As a conventional method for reducing inflowing phosphorus, addition of a lime-based material has been performed. The addition of this lime-based material was intended to form a sparingly soluble phosphate compound by reacting calcium ions with inorganic phosphorus, and fixedly remove phosphorus, which is a nutrient source for water-bloom. However, this lime-based material
Since the calcium carbonate film coats the surface of the material by reacting with carbonate ions existing in water, the supply of calcium ions from this material is stopped, and the effect is lost in a short period of time.
Further, since lime has a relatively high solubility, there is a problem that the pH of water rapidly rises when it is poured into water.

[0007]

The present invention is a device for purifying water in a water area where eutrophication is progressing or for purifying waste water containing a hardly decomposable organic substance, wherein the water in the water area is supplied with a magnesium ion supplying agent. The present invention relates to a water treatment device comprising a magnesium ion supply device to be brought into contact with a biodegradation treatment device including a tank in which a cord-like contact material is immersed.

Further, in the present invention, by disposing an ultraviolet irradiation device in the water treatment device, the decomposition can be further promoted.

Further, in the present invention, it is preferable that the magnesium ion supplying material is composed of one or more selected from magnesium oxide, magnesium hydroxide and magnesium carbonate.

The present invention relates to a device for purifying water in a water area where eutrophication is progressing. (1) Decomposing organic matter in environmental water by passing treated water through a tank in which a string-shaped contact material is immersed. By improving the biodegradation treatment tank that becomes inorganic, the biodegradation treatment can be performed more efficiently than before, and in addition, a device that enables decomposition of hardly decomposable organic substances, (2) Biodegradation A device for contacting the treated water with a magnesium ion supply agent capable of supplying magnesium ions to fix the inorganic phosphorus contained in the treated water to reduce the concentration of inorganic phosphorus in the treated water, and further (3) It is an apparatus with an apparatus for irradiating the water to be treated with ultraviolet rays mainly for the purpose of killing microalgae in the treated water and promoting decomposition.

[0011] The apparatus as described above not only decomposes organic substances, but also efficiently converts organic phosphorus into inorganic phosphorus, thereby making it difficult to react the inorganic phosphorus in the water to be treated with magnesium ions. By making it a soluble compound and immobilizing and removing it, it became possible to reduce phosphorus, which is indispensable for the growth of microalgae, for a long period of time, and to suppress the microalgae (blue-green algae) and suppress the abnormal occurrence.

The tank constituting the biodegradation treatment apparatus is as follows:
It is essential that the structure can be filled with a string-like contact material that directly biodegrades and that biodegradation can be effectively performed, but there is no restriction on the shape of the tank.
The string-like contact material propagates a group of microorganisms that efficiently biodegrade organic matter, and decomposes organic matter contained in water to be treated into inorganic matter.

The cord-like contact material preferably has a core cord and has a structure in which ring-shaped, scrubber-shaped or whisker-shaped fiber aggregates are radially distributed with respect to the core cord. In terms of material, it is not necessary to select any material as long as it is a material that is not easily decomposed by microorganisms. For example, synthetic fiber such as vinyl chloride, polyethylene, vinylon, polyvinylidene chloride, polypropylene, etc. or metal such as stainless steel, aluminum or glass. Fibers, etc. can be mentioned. In addition, the diameters of these materials are not a problem as long as they have such strength that they are not damaged by passing water.

Corrugated plate-shaped, mesh-shaped or mat-shaped contact materials have been used as conventional biodegradable fillers, but since the present string-shaped contact material has the above-mentioned structure, the volume of the void portion is large. In addition, since the area in contact with the water to be treated is large, it can be used as a filler for this biodegradation treatment tank to more efficiently convert organic phosphorus to inorganic phosphorus than conventional materials. You can However,
In a water treatment device consisting only of a biodegradation treatment device incorporating this cord-shaped contact material, the organic substances in the water to be treated are only decomposed by the microorganisms adhering to this contact material, so the inorganic phosphorus after decomposition is It will remain in the water to be treated and will be used again for biological growth in the water area. Therefore, it was impossible to reach the target water treatment level of the present invention with the water treatment device including only the biodegradation treatment tank filled with the string-shaped contact material. In order to reach the target water quality level of the present invention, magnesium ions are supplied to the water to be treated, which is one of the features of the present invention, to form and fix a sparingly soluble compound of magnesium ions and inorganic phosphorus. It will be possible only after it is removed. Therefore, it is important to arrange the device for supplying the magnesium ions inside and outside the biodegradation treatment tank. Further, preferably, by incorporating an ultraviolet irradiation device into this device, the present water quality can be more easily achieved.

Further, the feature of the biodegradation treatment tank is that the installation area can be reduced as described above, and in addition to the conventional corrugated plate-like biodegradation treatment tank, the fixing of microorganisms necessary for biodegradation of organic matter can be achieved. Even when it is prompt or when sludge and other deposits are accumulated between the resins and become clogged, corrugated stones that are conventionally used for water purification, corrugated stones, ceramics, or corrugated sheets made of polymer materials Unlike a mesh or mat-shaped contact material, it can be easily washed and reused, and the amount of microorganisms that can be retained is extremely large, so the period until the next washing process can be extremely long. -Type material. Moreover, it is possible to carry out biodegradation treatment so that installation plans and designs can be made without special techniques according to the area of the water area to be purified and the progress of eutrophication.

The magnesium ion supplying agent is necessary for the purpose of producing a sparingly soluble magnesium phosphate compound by being decomposed in the biological decomposition treatment tank and reacting with the inorganic phosphorus dissolved in the water to be treated. Therefore, the magnesium ion supplying agent may be any liquid, solid or slurry type as long as it can supply magnesium ions, but in order to maintain the magnesium ion supplying effect for a long period of time. Is magnesium oxide,
One or two of magnesium hydroxide and magnesium carbonate
It is preferably a magnesia-based powder or granular material composed of at least one kind.

For the purpose of producing a sparingly soluble phosphoric acid compound in the water to be treated, the reason why the soda-based material is used instead of the conventional lime-based material as in the present invention is that the pH which varies depending on the dissolution is in the soda-based material. The smaller is the pH of the environmental water
It is possible to operate in the interior, the reactivity with carbonate ions is low, the reactivity with inorganic phosphorus does not deteriorate due to the formation of carbonic acid compounds, and the solubility is low compared to lime type, so it can be used for a long time. This is because the reactivity continues over time, and the solubility of the sparingly soluble phosphoric acid compound generated in the pH range of the environmental water is lower in the magnesia system, so that the adsorption efficiency is higher.

Ultraviolet irradiation is carried out mainly for the purpose of removing algae which have already abnormally occurred in the eutrophic water area in a short time. The decomposition of algae is promoted by irradiating the liquid to be treated with ultraviolet rays in the apparatus. The decomposed organic phosphorus of algae is processed in the biological treatment tank as described above and decomposed into inorganic phosphorus. The cost problem, which is a drawback of the UV irradiation method, can be obtained by irradiation in a short time by using the biodegradation treatment method and contact with a magnesium ion supply agent in combination, and especially eutrophication of lakes and marine algae abnormalities It is also possible to design it so that it is carried out in a short period during the season when it is expected to occur and that it is effective with a minimum of equipment.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION A specific device will be described below. Basically, this treatment device continuously pumps the water in the eutrophic water area to the treatment tank and returns it to the original water area after the treatment. Continuous treatment in the external treatment tank of the treated water area is desirable as a method for performing the treatment intensively and effectively while minimizing the burden on other organisms in the treated water area. It is essential that this treatment device includes a step of decomposing organic phosphorus into inorganic phosphorus by a biodegradation method, and a step of supplying magnesium ions to the inorganic phosphorus in the water to be treated, and it is preferable that the alga-killing by ultraviolet irradiation is performed. Is included. In the present apparatus, there is no problem in the order of the steps, and it does not matter which step is performed first. If the treatment tank and the water to be treated are separated from each other, the equipment may be installed on the ground next to the water to be treated, on the water, or in the water, but for the purpose of purifying all water such as lakes and marshes. For example, it is more effective to design the pumping outlet for treated water and the drain outlet for treated water from the equipment separately.

A schematic view of the biodegradation treatment tank according to the present invention is shown in FIGS. 1 and 2 as an example. As described above, the shape is not limited and may be a cylindrical shape as shown in FIG. 1 or a box shape as shown in FIG. In addition, a partition may be attached to fix the contact material for the purpose of preventing the contact material filled with the contact material from being blocked. At this time, it is desirable to fill the cord-shaped contact material so as not to hinder the passage of water.

In the water treatment device comprising only the biodegradation treatment device in which the cord-like contact material is incorporated, only the treatment of decomposing the organic matter in the water to be treated by the microorganisms attached to the cord-like contact material is performed. Inorganic phosphorus remains in the water to be treated and becomes a cause of being used again for biological growth in the water area. Corrugated plates, meshes, or mats have been used as conventional contact materials, but the filling of this string-shaped contact material makes it more efficient for inorganic phosphorus conversion of organic phosphorus in this biodegradation treatment tank. Will be converted. However, the decomposed inorganic phosphorus remains in the water to be treated and becomes a cause of being used again for biological growth in the water area. Therefore, it is important to incorporate a step of fixing inorganic phosphorus by supplying magnesium ions and removing it from water, which is one of the features of the present invention. Magnesium ions are supplied for the purpose of fixing and removing the inorganic phosphorus, and a sparingly soluble compound is formed to be fixed and removed. It is important to arrange the device for supplying this magnesium ion inside and outside the biodegradation treatment tank. With the device incorporating this biodegradation treatment tank and magnesium ion supply device, it becomes possible to make inorganic phosphorus after organic matter decomposition into a sparingly soluble compound, and to fix and remove it, and in the eutrophied water area which is the object of the present invention. First reach the water purification level of. Further, preferably, by incorporating an ultraviolet irradiation device into this device, the present water quality can be more easily achieved.

Next, FIG. 3 shows an outline of an apparatus for improving the purification performance by installing a tank serving as a magnesium ion supply device in contact with the magnesium ion supply agent in the biodegradation treatment tank and further loading an ultraviolet irradiation device thereon. In this figure, pump 1
The water in the eutrophic water area taken by is sent to the treatment device. The treatment device comprises an ultraviolet irradiation device 2, a biodegradation treatment tank 3, and a magnesium ion supply tank 4, and is returned to the water area after passing through each process. In FIG. 1, the water to be treated is shown to pass through the treatment steps in the order of 3 → 2 → 4, but the order of passing the treatments may be fixed at any step, or at the same time. .

The pump indicated by 1 in the figure may be of any type as long as it can take in and transfer water in the water to be treated. As the ultraviolet irradiation device 2, a commercially available low-pressure ultraviolet lamp was installed.
When it is used for the purpose of removing microalgae that have already occurred in the water area, it can be removed if it is installed more than for the purpose of suppressing abnormal occurrence, but it can be removed by increasing the number of ultraviolet lamps. The time required can be shortened.

The biodegradation treatment tank 3 of the treatment apparatus is filled with a string-like contact material and uses microorganisms to convert organic substances into inorganic substances. A partition plate is attached to the receiving tank to pass water through the contact material. We devised a filling structure that does not interfere. With this filling structure, the amount of microorganisms retained per unit volume can be increased, the treatment capacity can be improved, and the decomposition treatment of hardly decomposable organic substances can be performed. With this structure, microorganisms that biodegrade biologically between the resins between the filled cord-shaped contact materials can be efficiently propagated, and the pollutants that cause eutrophication contained in the water to be treated pass through the biofilm to the surface of the packing material. And, it can be efficiently decomposed by microorganisms between the fillers, and inorganic phosphorus for fixing and removing phosphorus in the water to be treated according to the present invention is produced.

The magnesium ion supply tank 4 of the processing apparatus may have any shape as long as the magnesium ion supply agent can contact the water to be treated. Magnesium ions are supplied for the purpose of producing a sparingly soluble magnesium phosphate compound by reacting with the dissolved inorganic phosphorus that is generated by the efficient decomposition of organic phosphorus in water in the aforementioned biodegradation treatment tank. It Due to such an effect, it becomes possible to reduce phosphorus in water for the first time, and water purification in a eutrophic water area is achieved. If the magnesium ion supply agent is liquid or slurry-like, a pump for addition and a pH meter and equipment for adjusting the flow rate are required to prevent the pH of the water to be treated from dropping. Magnesium-based materials composed of one or more of magnesium oxide, magnesium hydroxide or magnesium carbonate in order to minimize the equipment to be operated and to maintain the magnesium ion supply effect for a long period of time. Is preferably added.

FIG. 4 shows a biodegradation treatment tank and a magnesium ion supply tank. The supplied water to be treated is gradually passed through the biodegradation treatment tank from the bottom of the apparatus, and is overflowed to be sent to the magnesium ion supply tank by the amount supplied. As shown in FIG. 4, a partition is put in the tank, and the string-like contact material is hung between the partitions in a direction horizontal to the flow of water, whereby it can be used as an efficient biodegradation processing tank. By adding an additional function to the shape of this device, such as installing an extraction port at the bottom of the tank for discharging the residue that cannot be biodegraded, and installing a weir to prevent the magnesium ion supply agent from flowing out, Practicality is enhanced.

When a large-scale device is required, it is possible to achieve the object by connecting the basic device having the shape shown in FIG. 4 and increasing the surface area as shown in FIG. If there is a particular problem, it may be cylindrical. The overflow of the biodegradation treatment tank may be performed inside the biodegradation treatment tank as shown in FIGS. 6 to 9 and not visible from the outside.

The order of the treatment steps will be described with reference to FIGS. 6 to 9. It is desirable that the phosphorus decomposed from the organic state to the inorganic state in the biodegradation treatment tank is fixed without delay by the magnesium ion supplying agent. Ideally, there is a magnesium ion supply tank immediately after the biodegradation treatment tank as in 6, but in reality, the circulation speed of the water to be treated is overwhelming compared to the speed at which algae use mineralized phosphorus for growth. Since it is a relatively large device, there is no problem even if there is a magnesium ion supply tank before the biodegradation processing tank as shown in FIG. If the magnesium ion supply tank is externally attached to the biodegradation treatment tank, it may be designed to be installed in the biodegradation treatment tank as shown in FIG.
The same applies to the ultraviolet irradiation device. In FIG. 9, the biodegradation treatment tank is installed so as to be submerged in the water to be treated. However, it may be buried in the soil or installed on the ground depending on the purpose and the installation environment. Hereinafter, description will be made using examples.

[0029]

【Example】

Example 1 3 m ³ of water was added to a water tank in which water-bloom was already generated,
Eight Nishikigoi were raised. Next, the biodegradation treatment tank was installed as shown in FIG. Tank was processed PVC steel cylinder having a diameter of 50 cm, was filled with commercially available polyvinylidene chloride manufactured by string-like contact member so as not to interfere with the water flow as the total volume of 0.2 m ³ of filling unit, filling and passed through A biofilm was formed on the surface of the material for use. The magnesium ion supply tank was attached to the outside of the water tank, and 2 kg of magnesium hydroxide as a magnesium ion supply agent was charged into the tank. The water to be treated that passed through the magnesium ion supply tank was pumped to the biodegradation treatment tank installed in the breeding water tank, and circulation was started in the water tank → magnesium ion supply tank → biodegradation treatment tank → water tank. The transparency of the breeding water in the breeding aquarium when the circulation was started was 1.8 cm. The transfer capacity of the pump was set so that the total amount of water in the water tank could be transferred twice a day. The transparency of the breeding water in the breeding aquarium on the 3rd day was 25 cm for the first time when the pump was operated, and exceeded the transparency of 100 cm on the 7th day. After 30 days, when the transparency exceeded 100 cm, it seemed that the decomposition ability of the filling material was still sufficient.
On the 8th day, the filler was lightly washed with tap water to wash off the adhered substances and discarded outside the system. After that, water was continued for another 30 days, but the transparency remained stable and exceeded 100 cm. From these results, it was confirmed that the purification effect of water quality could be maintained stably for a long time. In addition, it was confirmed that it can be regenerated by lightly washing it with tap water, and that water can be maintained for a long period of time without water quality deterioration even if water is passed through after regeneration.

Example 2 In the apparatus of Example 1, a commercially available 15 was placed on the biodegradation treatment tank.
The same experiment was conducted with two W ultraviolet lamps installed. The transparency is 1 on the 3rd day after starting the operation of the pump and the UV lamp.
It exceeded 00 cm. Similar to Example 1, it seems that the decomposition ability of the packing still remains, but after the start of the experiment 3
On the third day, the filler was lightly washed with tap water to wash off the adhered substances, and discarded outside the system. After that, the cycle of continuing water passage for 30 days and then washing the filler was repeated twice, but the transparency was stably maintained above 100 cm. It was confirmed that the water in the breeding aquarium is transparent, and that UV irradiation is added to the water purification process by the biodegradation treatment tank to promote water purification, and water with high transparency and good water quality can be stably maintained for a long period of time. .

Example 3 A water purification tank made of iron in which the biological decomposition treatment tank and the magnesium ion supply tank shown in FIG. 3 are integrated (biological decomposition treatment tank volume 4 m ³ , magnesium ion supply tank volume 0.4 m ³ ).
Was installed next to a concrete water tank containing 70 m ³ of water that had already generated water-bloom. 4 Nishikigoi in this aquarium
Five animals were bred, and commercially available feed was administered at 350 g / day. In the biodegradation treatment tank of the water purification tank, a string-shaped contact material used in Examples 1 and 2 having a total length of 30 m was attached to a PVC pipe frame having a width of 2 m and a height of 1 m, and the cord-like contact material was installed at an interval of 6 cm in the tank. One sheet was filled (total length: 510 m). The UV irradiation device is installed on the biodegradation treatment tank, and a commercially available 15W UV lamp is used.
I installed a book. 20 kg of magnesium hydroxide was added to the magnesium ion supply tank. The treated water pumped up by the pump was sent to the biodegradation treatment tank at a flow rate of 6 m ³ / hour, and circulation was started in the water tank → biodegradation treatment tank → magnesium ion supply tank → water tank. The transparency of the water to be treated was 15 cm when the circulation was started, but the transparency exceeded 100 cm 5 days after the start of the experiment. After 30 days, when the transparency exceeded 100 cm, it seems that the decomposition ability of the filling material still remained, but on the 35th day after the start of the experiment, the filling material was lightly washed with tap water. The deposit was washed off and discarded outside the system. After that, water was continued for another 30 days, but the transparency remained stable and exceeded 100 cm. The washing cycle was repeated 3 times on the 30th day, and the transparency was stably maintained at a state of exceeding 100 cm. From this result, the purification effect of water quality was confirmed,
It was also confirmed that it could be stably maintained for a long period of time. In addition, as in Examples 1 and 2 described above, even if the amount of water to be treated becomes large, the water quality will be deteriorated even if water is passed through after regeneration by a very simple regeneration process of lightly washing with tap water. It turned out that it can be stably maintained for a long period of time. Therefore, it was found that this device is extremely effective in purifying the water quality generated by water-bloom.

Comparative Example 1 After breeding Nishikigoi in the same shape of aquarium used in Example 1, 0.7 m ^{2 of} corrugated sheet conventionally used for purification of environmental water was laid and The water in the water tank was circulated under the same conditions. Aeration was performed at an amount of 0.12 m ³ / min in order to accelerate the decomposition of organic substances in the water tank. Although the water circulation and aeration in the aquarium were started and the transparency was measured for 5 days, the transparency of the breeding water was 1.8 cm as in the start of the experiment.
After that, the transparency of the breeding water was measured every few days.
The effect of water purification on the corrugated plate in the water area having a high biological load which was in the range of up to 2.5 cm was lower than that of the water treatment device of the present invention.

COMPARATIVE EXAMPLE 2 An example was carried out except that the biodegradation treatment tank used in Example 3 was filled with a PVC-made thread having a diameter of 0.5 mm which was processed so as not to hinder the passage of water. A water treatment experiment was conducted under the same conditions as in 3. Although the transparency of the breeding water at the start of water flow was 14 cm, the transparency exceeded 100 cm on the 10th day. After that, the transparency exceeded 100 cm for 15 days, but it was considered that the amount of deposits on the surface of the mat-like filler became so large that the processing capacity of the filler was reached, and the transparency fell below 100 cm. Therefore, it was washed with tap water to thoroughly wash off the deposits. After that, water continued to be passed through, but the transparency finally exceeded 100 cm on the third day after water was passed again. From this result, when the conventional contact material is used, the water quality treatment capacity is inferior to that when the cord-like contact material is used, and the period required for the reprocessing of the filler is short,
It turned out that the regeneration process had to be carried out frequently.

Comparative Example 3 A water treatment experiment was conducted under the same conditions as in Example 3 except that the magnesium ion supplying device used in Example 3 was not charged with a magnesium ion supplying agent and was not irradiated with ultraviolet rays. went. The transparency of breeding water at the start of water flow is 16
Although it was cm, the transparency on the 7th day was 23 cm.
After that, the experiment was continued for 21 days, but the transparency changed between 15 cm and 25 cm. The string-shaped contact material filled in the biodegradation treatment tank had a large amount of adhered microbial layers, and was required to be washed and regenerated with tap water on the 10th day after the start of the experiment. From these results, it was confirmed that in water purification treatment using a water treatment device consisting only of a biodegradation treatment tank filled with a string-shaped contact material, the transparency is hardly improved and the filler must be washed frequently. It was found that water purification using only the biodegradation treatment tank filled with the string-shaped contact material had almost no effect.

[0035]

INDUSTRIAL APPLICABILITY As described above, in the biodegradation method for purifying the water quality of eutrophic lakes, the biodegradation is improved by improving the contact method between the microorganisms that decompose organic matter and the water to be treated. It will be possible to reduce the scale of equipment to be used, and it will be possible to improve the water quality of water bodies on a larger scale than before. In addition, by purifying water to be eutrophied by combining the treatment of water that has undergone biodegradation with a magnesium ion supply agent to reduce the phosphorus concentration in environmental water and by promoting the decomposition of organic substances by UV irradiation. It becomes possible to carry out with a miniaturized device. The water treatment device according to the present invention does not require conventional large-scale and expensive equipment for each process, and can be easily designed, produced, and operated without any special technology or special equipment. It has the advantages of being safer for the environment because it uses the purification power in nature without using it, has few operating facilities, and has a low running cost.

[Brief description of drawings]

FIG. 1 is a schematic view of a biodegradation treatment apparatus having a cylindrical tank used in an embodiment of the present invention.

FIG. 2 is a schematic diagram of a biodegradation treatment apparatus having a box-shaped tank shown in the present invention.

FIG. 3 is a schematic view of a treatment step of the water treatment step shown in the present invention.

FIG. 4 is a top view, a side view, and a front view of a biodegradation treatment apparatus having a box-shaped tank provided with a magnesium ion supply tank shown in the present invention.

FIG. 5 is a schematic view of a large-scale treatment process of the water treatment device shown in the present invention.

FIG. 6 is a schematic diagram of a biodegradation processing apparatus in which a magnesium ion supply tank is arranged at the outlet of the tank of the biodegradation processing apparatus shown in the present invention.

FIG. 7 is a schematic diagram of a biodegradation treatment tank in which a magnesium ion supply tank is arranged at the inlet of the tank of the biodegradation treatment apparatus shown in the present invention.

FIG. 8 is a schematic view of a biodegradation treatment tank in which a magnesium ion supply tank is arranged inside the tank of the biodegradation treatment apparatus shown in the present invention.

FIG. 9 is a schematic diagram of a method for disposing the biodegradation treatment device, the magnesium ion supply tank, and the ultraviolet irradiation device shown in the present invention.

[Explanation of symbols]

 1 Pump 2 Ultraviolet irradiation device 3 Biodegradation treatment tank 4 Magnesium ion supply tank

Claims (4)

[Claims] 1. An apparatus for purifying water in a water area where eutrophication is progressing or for purifying waste water containing a hardly decomposable organic substance, and a magnesium ion supply apparatus for bringing water in the water area into contact with a magnesium ion supply agent, A water treatment device comprising a biodegradation treatment device comprising a tank in which the string-shaped contact material is immersed. 2. The water treatment device according to claim 1, wherein an ultraviolet irradiation device is arranged in the water treatment device. 3. The cord-shaped contact material has a core cord, and the ring-shaped, scourer-shaped or whisker-shaped fibrous aggregates are radially distributed with respect to the core cord. Or the water treatment device according to 2. 4. The water treatment apparatus according to claim 1, 2 or 3, wherein the magnesium ion supplier is composed of one or more selected from magnesium oxide, magnesium hydroxide and magnesium carbonate. .