JP4649887B2 - Water purification promotion material, highly functional water purification material, and water purification method using them - Google Patents

Description

  The present invention relates to a water purification promotion material and a highly functional water purification material applied when purifying water containing nitrate nitrogen, and a water quality purification method using them.

  Recently, nitrate nitrogen has become a problem as a harmful pollutant contained in groundwater and tap water. Such problems are thought to be caused by the eutrophication of water quality by nitrogen and phosphorus in closed water areas such as lakes and rivers, and as a result, flowing into groundwater in the form of nitrate nitrogen.

  Nitrate nitrogen is a substance produced as a result of decomposition of nitrogen components in agricultural chemicals, herbicides, fertilizers, manure, etc. by microorganisms, but when nitrate nitrogen enters the body, it is reduced and nitrous acid is added. It changes to natural nitrogen and produces a substance called nitrosamine, which is a carcinogen, or causes so-called methemoglobinemia, which decreases the function of hemoglobin in the blood and causes oxygen deficiency, resulting in cyanosis. Has been pointed out.

  Therefore, nitrate nitrogen contained in rivers, lakes, groundwater, etc., which is the source of drinking water, as well as water purification plants, must be removed in advance so that the concentration does not cause health damage.

Japanese Unexamined Patent Publication No. 2000-232728 Japanese Patent Laid-Open No. 10-113693 JP-A-10-286590

  As a method of removing nitrate nitrogen contained in water, attempts have been made to reduce the nitrate nitrogen to nitrogen gas by a plant, and some have already been put into practical use.

  Here, as a method put into practical use in the plant, there are a sludge sludge method, a dual sludge method, a single sludge method, etc., all of which are hydrogen donors (usually, for reducing nitrate nitrogen in an intermediate step). Methanol) is required separately, or the addition of an alkaline agent that neutralizes the pH is required, and as a result, the reaction process becomes complicated. There was still room for improvement in processing at low cost.

  The present invention has been made in consideration of the above-described circumstances, and is a reaction accelerator capable of efficiently removing nitrate nitrogen contained in water at low cost, a water purification method using them, and a highly functional water purification material. The purpose is to provide.

In order to achieve the above object, the water purification promoter according to the present invention has a strong acid rock or rock distributed in a volcanic area, inhabited by sulfur-oxidizing bacteria that can oxidize sulfur as a simple substance. It is produced by the pulverized product.

  Moreover, the water purification | cleaning promotion material which concerns on this invention makes the said rock or its ground material the rock of a porous structure, or its ground material.

Also, high-performance water purification material according to the present invention as described in claim 3, the sulfur is a single body oxidizable sulfur oxidizing bacteria inhabit, strongly acidic rock or the ground product distributed in volcanic And a water purification material prepared by solidifying sulfur as a simple substance with a lime-based hydraulic material.

  Moreover, the highly functional water purification material which concerns on this invention uses the rock or its ground material as the rock of a porous structure, or its ground material.

  Moreover, the highly functional water purification material which concerns on this invention uses the said lime type hydraulic material as alkaline waste mud.

In addition, the water purification method according to the present invention, as described in claim 6 , adds the highly functional water purification material according to claim 3 to contaminated water containing nitrate nitrogen, whereby the sulfur is converted into an electron donor. The nitrate nitrogen is reduced to nitrogen gas.

The water purification promoting material according to claim 1 is made of a strongly acidic rock or a pulverized product thereof inhabited by sulfur-oxidizing bacteria capable of oxidizing sulfur as a simple substance and distributed in a volcanic area .

  In this way, the sulfur-oxidizing bacteria are placed in a situation where they can easily act without changing the habitat, and when sulfur as a simple substance is supplied in such a situation, the sulfur-oxidizing bacteria quickly oxidize sulfur. At the same time, the sulfur serves as an electron donor to reduce nitrate nitrogen and render it harmless to nitrogen gas.

  Although elemental sulfur is also referred to as elemental sulfur, it is not appropriate to use the term element in the definition of a substance. Therefore, in this specification, elemental sulfur or elemental sulfur is referred to. Unless otherwise specified, sulfur in the present specification means single sulfur.

  There are several types of sulfur-oxidizing bacteria, but those that can oxidize sulfur, which is a simple substance (hereinafter referred to as simple sulfur-oxidizing bacteria in this specification, which can oxidize sulfur compounds, Distinguish from general sulfur-oxidizing bacteria that are inferior in their ability to decompose sulfur, but simple sulfur-oxidizing bacteria do not mean bacteria that only oxidize simple sulfur, but at least bacteria that can oxidize simple sulfur. Is meant only in limited places, and is rarely found in paddy fields and fields where nitrate nitrogen is present in large quantities due to excessive administration of fertilizer.

Here, it has been proved by the applicant's experiment that the strongly acidic rock distributed in the volcanic area or the pulverized product thereof contains a large amount of the above-mentioned simple sulfur-oxidizing bacteria.

  In other words, it is well known that the volcanic gas ejected in the volcanic area contains sulfur, which is solidified and precipitated as sulfur flower. Experiments confirmed that a large amount of simple sulfur-oxidizing bacteria were contained in the distributed strong acid rocks.

  Based on the knowledge obtained in these experiments, the present applicant has found that the above-described sulfur deposits adhere to and deposit on the surrounding rocks (mainly volcanic rocks), and the energy of the single sulfur-oxidizing bacteria in the rocks oxidizes sulfur. It is assumed that the rocks are strongly acidic due to the sulfuric acid produced by sulfur oxidation, and that the rocks are strongly acidic due to the carbon dioxide obtained from carbon dioxide in the air. As a result, it was obtained as a new finding that a large amount of simple sulfur-oxidizing bacteria were contained as estimated.

Therefore, when strongly acidic rocks or pulverized materials distributed in the volcanic area are collected , simple sulfur-oxidizing bacteria inhabit them, and strong acidic rocks or pulverized materials are used as a carrier for simple sulfur-oxidizing bacteria. Since it is used as it is, the environment does not change for the bacterial cells, so if simple sulfur is supplied, the simple sulfur can be oxidized quickly, and the simple sulfur can become an electron donor to reduce nitrate nitrogen. It becomes possible.

  Further, if the above-mentioned rock or pulverized product thereof is a rock having a porous structure or pulverized product thereof in particular, simple sulfur-oxidizing bacteria can enter the porous gap and inhabit a large amount, and as a result, the nitrate state The decomposition efficiency of nitrogen can be improved.

The elemental sulfur oxidizing bacteria, for example, there is Thiobacillus thiooxida n s.

The highly functional water purification material according to claim 3 is a water purification purification material produced by a strongly acidic rock or a pulverized product thereof inhabited by sulfur-oxidizing bacteria capable of oxidizing sulfur as a simple substance, The water purification method according to claim 6 , wherein the sulfur is solidified with a water purification material obtained by solidifying sulfur with a lime-based hydraulic material, and the highly functional water purification material includes nitrate nitrogen. Add highly functional water purification material for contaminated water.

  In this case, since the habitat environment of the elemental sulfur-oxidizing bacteria does not change, the elemental sulfur is rapidly oxidized by supplying elemental sulfur from the water purification material as described in claim 1, and the sulfur is converted into an electron. It becomes a donor and reduces nitrate nitrogen to make it harmless to nitrogen gas.

Here, when a strongly acidic rock distributed in a volcanic area or a pulverized product thereof is collected, a simple sulfur-oxidizing bacterium lives in the rock, and the simple sulfur-oxidizing bacterium and a strongly acidic rock or a pulverized product thereof. Since it is used as a carrier without being separated, the environment does not change for the cells, so the single sulfur supplied from the water purification material is quickly oxidized, and the single sulfur becomes an electron donor and nitrate nitrogen. Can be reduced.

  Further, if the above-mentioned rock or pulverized product thereof is a rock having a porous structure or pulverized product thereof in particular, simple sulfur-oxidizing bacteria can enter the porous gap and inhabit a large amount, and as a result, the nitrate state The decomposition efficiency of nitrogen can be improved.

  On the other hand, sulfur is oxidized by itself to become sulfuric acid, which is neutralized by the alkaline component of the lime-based hydraulic material. For example, the sulfuric acid becomes neutral gypsum by neutralizing with calcium carbonate or calcium hydroxide in the lime-based hydraulic material.

  The lime-based hydraulic material contains an aqueous solution of cement and lime, but if the lime-based hydraulic material is made into alkaline sludge, conventionally, the alkaline sludge that had to be disposed as industrial waste, There is also a remarkable effect that it can be effectively used as a raw material for detoxifying nitrate nitrogen.

  By the way, in the civil engineering and construction industry, a large amount of alkaline waste mud is generated by mud construction methods such as the underground continuous wall construction method, and its disposal has become a big social problem.

The present invention according to claim 5 is a knowledge obtained as a result of repeated researches conducted by the present applicant while taking into account such a problem and the social situation in which sulfur is surplus in the desulfurization process in petroleum refining and the like. Needless to say, this is a very significant invention in the industry.

  Alkaline wastewater is mainly for wastewater generated by the underground wall method and the muddy water method such as the muddy water shield, but for the convenience of transportation, the wastewater added with lime-based hydraulic material for the purpose of solidification. However, as long as it exhibits alkalinity, it is not limited to the waste mud generated by the mud construction method described above.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a water purification purification material, a highly functional water purification material, and a water purification method using them according to the present invention will be described with reference to the accompanying drawings. Note that components that are substantially the same as those of the prior art are assigned the same reference numerals, and descriptions thereof are omitted.

  FIG. 1 is a flowchart showing an implementation procedure of a water purification method using the water purification promoting material and the high-performance water purification material according to the present embodiment.

As it can be seen in the figure, in the water purification method according to the present embodiment, or not a present embodiment consisting of a single body sulfur oxidizable sulfur-oxidizing bacteria (elemental sulfur-oxidizing bacteria) and a carrier of the single body sulfur oxidizing bacteria A water purification promoting material according to the embodiment is manufactured (step 101).

  In production, rocks or their pulverized materials inhabited by simple sulfur-oxidizing bacteria, specifically, strongly acidic rocks distributed in volcanic areas or pulverized materials thereof may be collected.

In this way, since a large amount of elemental sulfur-oxidizing bacteria are contained in the strongly acidic rocks or pulverized products distributed in the volcanic area, when elemental sulfur is supplied, the elemental sulfur-oxidizing bacteria quickly become elemental sulfur. you oxidize.

The elemental sulfur oxidizing bacteria, for example, there is Thiobacillus thiooxida n s.

  On the other hand, a water purification material according to the present embodiment is produced by solidifying solid sulfur with alkaline waste mud, which is a lime-based hydraulic material (step 102).

  The alkaline waste mud that is the raw material should use the waste mud generated by underground continuous wall construction. In continuous underground wall construction, when excavating the ground, in order to prevent the excavated hole wall from collapsing, excavation is carried out while putting muddy water as a stabilizing liquid in the excavation hole. Replace and collect the stable solution while placing.

  Although this spent stable liquid becomes waste mud, it is replaced and recovered with underwater concrete, so cement is mixed in the waste mud, and therefore, such waste mud becomes alkaline waste mud. Yes.

  As the simple sulfur, sulfur that is a by-product generated in the desulfurization process of petroleum refining may be used.

  When solidifying the single sulfur with alkaline waste mud, the alkaline waste mud is left to solidify as it is, or cement and lime are additionally added to solidify it to obtain a solid waste, and the waste mud solid and the single sulfur are solidified. Mix.

  The mixing ratio of the sludge solidified body and elemental sulfur is, for example, 50 to 90:50 to 10 by weight.

  It should be noted that elemental sulfur may be added to the alkaline waste mud and then left as it is to solidify, or cement or lime may be additionally added to solidify.

  It is desirable to adjust the size (particle size) of the produced water purification material as appropriate according to the form of use. Such particle size adjustment can also be performed at the stage of waste mud solidified, and if the sulfur is mixed while crushing the waste mud solidified to an appropriate size with a crusher or the like, the particle size adjusting step and the mixing step Can be done in one step.

  Next, the high-performance water purification material comprising the above-described water purification promoter and water purification material is added to the contaminated water containing nitrate nitrogen (step 103).

  By doing so, since the habitat environment does not change for the elemental sulfur-oxidizing bacteria, the elemental sulfur is quickly oxidized by supplying elemental sulfur from the water purification material, and the elemental sulfur becomes an electron donor to form nitrate. Reduces nitrogen and renders it harmless to nitrogen gas.

  Various forms of use are possible in purifying contaminated water containing nitrate nitrogen using the produced high-performance water purification material.

  For example, a high-performance water purification material is filled in a treatment tank having a drain outlet in advance, and the above-described contaminated water is introduced into the treatment tank and left in an anaerobic environment.

  In this way, during the standing, the elemental sulfur-oxidizing bacteria oxidize elemental sulfur, and at the time of oxidation, sulfur becomes an electron donor to denitrify nitrate nitrogen and reduce it to nitrogen gas.

  While monitoring the concentration of nitrate nitrogen in the treatment tank, the original contaminated water can be judged to have been denitrified if it is below a certain concentration, for example, a concentration that is harmless to human health. Therefore, this is drained from the drain outlet as treated water.

  Sulfuric acid is produced with the oxidation reaction of sulfur, but this sulfuric acid is neutralized by calcium hydroxide and calcium carbonate contained in the alkaline waste mud, and settles in the treatment tank as gypsum. It can be discharged directly into rivers and so on.

  Further, the above-described high-performance water purification material may be introduced into a drainage ditch, a lake or a wetland where groundwater contaminated with nitrate nitrogen overflows.

  As described above, according to the highly functional water purification material and the water purification method using the same according to the present embodiment, a large amount of simple sulfur-oxidizing bacteria are present in the strongly acidic rock distributed in the volcanic area or the pulverized product thereof. Inhabited in the area, and the strongly acidic rocks or pulverized products thereof are carriers for the single sulfur-oxidizing bacteria, so the environment does not change for the cells, and the single sulfur supplied from the water purification material is quickly oxidized, The simple sulfur becomes an electron donor, and nitrate nitrogen can be reduced.

  On the other hand, although sulfur is oxidized by itself to become sulfuric acid, the sulfuric acid is neutralized by the alkaline component in the alkaline sludge. For example, sulfuric acid becomes neutral gypsum by neutralizing with calcium carbonate or calcium hydroxide in alkaline waste mud.

  In addition, alkaline drainage that has been conventionally disposed as industrial waste can be effectively used as a raw material for detoxifying nitrate nitrogen.

  Furthermore, since alkaline waste mud has a high phosphorus adsorption capacity, the highly functional water purification material according to the present embodiment has not only the action of nitrate nitrogen purification but also the action of adsorbing and removing phosphorus.

  Moreover, according to the highly functional water purification material and the water purification method using the same according to the present embodiment, the raw material for detoxifying nitrate nitrogen from alkaline waste mud that has been conventionally disposed as industrial waste. As a result, it has a remarkable effect that it can be used effectively.

  In addition, according to the highly functional water purification material and the water purification method using the same according to the present embodiment, it is possible to effectively utilize sulfur that tends to be surplus in the desulfurization step in petroleum refining or the like.

  In this embodiment, water contaminated with nitrate nitrogen is purified using a highly functional water purification material. However, the water purification material according to the present invention literally promotes the reduction of nitrate nitrogen. It does not necessarily need to be used together with the water purification material according to the present embodiment, and may be used together with a water purification material obtained by solidifying sulfur, which is a compound, with a lime-based hydraulic material. .

  Although not particularly mentioned in the present embodiment, if a strongly acidic rock distributed in a volcanic area or a pulverized product thereof is a porous rock or a pulverized product thereof, a simple sulfur-oxidizing bacterium is a porous material. Since it enters into the gap and can live in a large amount, it can improve the decomposition efficiency of nitrate nitrogen as a result.

  Porous rocks or pulverized materials are often found in strongly acidic rocks or pulverized materials distributed in volcanic areas that have been hydrothermally denatured. That's fine.

  FIG. 2 shows the results of experiments confirming the effects of the highly functional water purification material according to the present invention. The horizontal axis represents the specimen and the vertical axis represents the concentration of nitrate nitrogen.

Here, the standard solution (control), was 100ppmK NO ₃ dissolved solution.

  Specimen 1 is obtained by adding a water purification material obtained by solidifying single sulfur with a lime-based hydraulic material to a standard solution. Specimen 2 is a strongly acidic mudstone containing the above-described water purification material and iron sulfide ( Sample 3 is a mixture of the above-described water purification material and water purification promotion material mixed at a mass ratio of 2: 1. A functional water purification material was added to the standard solution, and the water purification material was a pulverized product of strongly acidic rock distributed in the volcanic area (pH is about 2).

  In addition, simple sulfur is petroleum refined sulfur having a particle size of 5 mm or less, lime-based hydraulic material is poor blended mortar (water cement ratio is 1, sand cement ratio is 5, both are mass ratio) and bentonite mud (500 ml of water, Bentonite mortar was prepared by mixing 50 g of bentonite with a volume ratio of 1: 1. Next, the above-mentioned simple sulfur and lime-based hydraulic material were mixed with a mixer, cured for 3 days, solidified, and then ground to 5 mm to 20 mm to produce a water purification material.

  From the graph of FIG. 2, after 81 days, in the case where only the water purification material was added to the standard solution (Specimen 1), the nitrate nitrogen concentration was 88 mg / L, and the water purification material and strongly acidic mudstone were standard solution. In the case where the nitrate nitrogen concentration was only reduced to 86 mg / L in the case (sample 2) added to the sample, a highly functional water purification material consisting of a water purification material and a water purification promotion material was added to the standard solution. In the case (Specimen 3), it can be seen that the nitrate nitrogen concentration has dropped to 67 mg / L.

  From these experimental results, it can be seen that nitrate nitrogen is efficiently reduced by the highly functional water purification material according to the present embodiment.

The flowchart of the water purification method using the highly functional water purification material which concerns on this embodiment. The graph which showed the effect of the highly functional water quality purification material which concerns on this embodiment.

Claims (6)

A water purification promoting material, characterized by being made of strong acid rocks or pulverized products thereof distributed in volcanic areas, inhabited by sulfur-oxidizing bacteria capable of oxidizing single sulfur. The rock or rock or water purification promoting material according to claim 1, wherein the its pulverized porous structure the pulverized product. Sulfur-oxidizing bacteria that can oxidize sulfur as a simple substance inhabit , water purification promoters made from strongly acidic rocks or pulverized products distributed in volcanic areas, and solid sulfur as a lime-based hydraulic material A high-performance water purification material characterized by comprising a water purification material. The highly functional water purification material according to claim 3, wherein the rock or pulverized product thereof is a rock having a porous structure or a pulverized product thereof. The highly functional water purification material according to claim 3 or 4, wherein the lime-based hydraulic material is alkaline waste mud. A water quality characterized in that by adding the highly functional water purification material according to claim 3 to contaminated water containing nitrate nitrogen, the sulfur acts as an electron donor and the nitrate nitrogen is reduced to nitrogen gas. Purification method.

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