JP2008245617A - Nutrient salt composition using farm and marine waste and for silicon supply to water area, and production system thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silicon supply material using chaff ash and shell, supplying silicon to water area so as to change the water area to be in environmental conditions on which diatom easily proliferates. <P>SOLUTION: Concerning a nutrient salt composition to be supplied to water area, promoting proliferation of the diatom of a preferential microalgae on water area, the nutrient salt composition to be supplied to water area is provided by being compounded with the chaff ash and pulverized calcium carbonate resources as the main ingredients, and a modification method of nutrient salt conditions in the water area is provided. Thereby, silicon is supplied to water area short in silicon so as to change the water area to be in environmental conditions on which the diatom proliferates easily. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a nutrient composition for supplementing silicon to water using agricultural and fishery wastes, etc., more specifically, for changing the nutrient environment of the water to an environment in which diatoms can easily grow, The present invention relates to a nutrient composition for supplying silicon to a new water area using rice husk ash which is an agricultural waste and a shell which is an aquatic waste, and a method for modifying the water environment by using the composition. The present invention provides rice husk ash, which is the residue of rice husk power generation using rice husks that are agricultural wastes, and a silicon material for water supply using calcium carbonate resources such as sea shells that are marine wastes. Yes, by supplying the silicon material to the silicon-deficient water area, it is possible to create an environment in which diatoms, which are important basic producers in the ecosystem of the water area, and are useful for high-level producers, can easily grow. A material for replenishing silicon to water is provided.

  Silicon is an essential element of diatom, which is a preferred microalgae in water. Due to the construction of a large-scale dam and an increase in the load of nitrogen and phosphorus on the sea area, relative silicon deficiency is being regarded as a problem (Non-patent Documents 1-11). Depending on the type of diatom, if the silicon concentration is 2-5 μmol / L or less in the sea area, its growth is hindered even if there is a sufficient amount of other nutrients (nitrogen, phosphorus) (Non-patent Document 11).

  Nitrogen and phosphorus uptake rates of flagellate algae are generally lower than that of diatoms. However, when silicon is insufficient, diatom growth is hindered, and it becomes an advantageous environment for flagellate algae that do not require silicon for growth (non- Patent Documents 9, 10, and 11). There are many species of flagellate algae that damage fish and shellfish, and as a result, it can adversely affect the ecosystem of the aquatic area, which can lead to a decline in production of fish and shellfish.

  Most of the silicon in the water is derived from rivers and is transported to the water by the weathering action of clay minerals. However, when large-scale dams are constructed, freshwater diatoms grow in the dam's still water, and silicon that has been transported to the sea until then is trapped in the dam lake, and silicon is supplied to the sea. It will decrease.

  If silicon is supplied to the water area lacking silicon, it is thought that the growth of flagellate algae can be suppressed and diatoms useful in the ecosystem of the water area can be propagated. Conventionally, for example, a method using steel slag has been proposed as a prior art for replenishing silicon and phosphorus to water areas (Patent Document 1). However, since steel slag is industrial waste of the mining industry, there is a possibility that harmful heavy metals and the like may be mixed in the refining process. On the other hand, rice husk ash and shells are materials derived from natural organisms, and it is considered that there is no problem even if they are returned to the natural world.

  In the Seto Inland Sea, the total amount of COD, phosphorus, and nitrogen is regulated to prevent drought nutrition, and drought nutrition is calming down except for some sea areas. However, since the total amount of phosphorus was controlled prior to the total amount of nitrogen, the entire sea area is in excess of nitrogen, which is a nutrient necessary for the growth of phytoplankton, resulting in a shortage of phosphorus ( Non-patent document 1).

  In addition, the development of dams and the like will reduce the inflow of silicon into the sea area and increase the number of silicon-deficient sea areas (Non-patent Documents 4-11). Such nutrient imbalances have a negative impact on the basic production of marine ecosystems, which is one of the factors that reduce the occurrence of harmful flagellar algae and fishery production.

  In addition, aquaculture farms of aquaculture that are actively practiced in Southeast Asian countries are in a state where dissolved inorganic nitrogen and dissolved inorganic phosphorus are excessive, and dissolved silicon is likely to be insufficient (Mishima, Presentation data). In such a situation, flagellar algae that are more harmful than diatoms and cyanobacteria are likely to grow.

JP 2003-134958 A Harashima: Coastal Ocean Research, 43, 39-44 (2005) “Verification of silica deficiency hypothesis based on ferry monitoring data” Officer, C.B.and J.H.Ryther (1980): The possible importance of silicon in marine eutrophication.Prog Mari Ecol.Prog.Ser., 3, 83-91 Tsunogai, S. and Y. Watanabe (1983): Role of dissolved silicate in the occurrence of phytoplankton bloom. J. Oceanogr. Soc. Jpn., 39, 231-239 Billen, G., C. Lancelot and M. Meybeck (1991): N, P, and Si retention along the aquatic continuum from land to ocean, p. 1944, In, Ocean Margin Processes in Global Change, eds.RFC, Mantoura , J.-M.Martin and R.Wollast, Wiley Humborg, C., V. Ittekot, A Cociasu and B. Bodungen (1988): Effect of Danube River dam on Black Sea biogeochemistry and ecosystem structure.Nature, 27, 385-388 Ittekot, V., C.Humborg and P.Schafer (2000): Hydrological alterations and marine biogeochemistry: a silicate issue? BioScience, 50,776-782 Vorosmarty, C.J., K.P.Sharma, B.M.Fekete, A.H.Copeland, J, Holden, J.Marble and J.A.Lough (1997): The storage and aging of continental runoff in large reservoir systems of the world.Ambio, 26, 210-219 Turner, R.E.and N.N.Rabalais (1994): Coastal eutrophication near the Mississipi river delta.Nature, 368,619-621 Turner Thomas, W.A., A.N.Dodson and F.M.H.Reid (1978): Diatom productivity compared to other algae in natural marine phytoplankton assemblages.J.Phycol., 14,250-253 Delmas, D., A. Herbland and SYMaestrini (1992): Environmental conditons which lend to increase in cell density of the toxic dinoflagellates Dinophysis spp. In nutrient-rich and nutrient-poor waters of the French Atlantic coast. Mar. Ecol. Prog.Ser., 89,53-61 Egge, J.K. and D L. Aksnes (1992): Silicate as regulating nutrient in phytoplankton competition Mar. Ecol. Prog. Ser., 83, 281-289

  Under such circumstances, the present inventor is able to replenish silicon according to the state of the water area, correct the nutrient salt state, and prepare an environment in which diatoms can easily grow. As a result of intensive research with the goal of developing silicon supplements for water bodies, the nutrient supplement composition for silicon supplements produced using rice husk ash of agricultural waste and crushed shells of marine waste As a result, the present inventors have found that the silicon supplement is useful and has completed the present invention. An object of the present invention is to provide a nutrient composition for replenishing water and replenishing silicon to the water to promote the growth of diatoms and a method for producing the same. Another object of the present invention is to provide a method for supplying the above composition to a water area to change the nutrient environment of the water area to an environment in which diatoms can easily grow.

The present invention for solving the above-described problems comprises the following technical means.
(1) A nutrient composition for replenishing silicon to promote the growth of diatoms, which are the preferred microalgae in the water area, which is a water area that contains rice husk ash and a pulverized calcium carbonate resource as main components. Nutrient composition for replenishment.
(2) The nutritive salt composition for water supply according to (1), wherein the rice husk ash is rice husk ash of agricultural waste or acid-treated rice husk ash obtained by treating it with nitric acid.
(3) The nutritive salt composition for water supply according to (1), wherein the rice husk ash is rice husk ash of rice husk power generation residue.
(4) The nutrient composition for water supply according to (1), wherein the pulverized product of the calcium carbonate source is a crushed shellfish shell, which is a marine waste.
(5) The nutrient composition for water supply according to (1), wherein the mixing ratio of shellfish and chaff ash is adjusted so as to approach 10: 6 by weight.
(6) A system for producing a nutrient composition for replenishing water according to any one of (1) to (5) above, comprising acid-treated rice husk ash treated with rice husk ash or nitric acid and a source of calcium carbonate A process for producing a nutrient salt composition for replenishing water by firing a mixture of pulverized products, and a neutral concentration of nitric acid-containing waste liquid discharged when producing acid-treated rice husk ash, neutralized with CaCO ₃ or shells to obtain a liquid A system for producing a nutrient salt composition for water supply comprising a process for producing a fertilizer.
(7) Supplying the nutrient composition composition for replenishing water according to any one of (1) to (5) above to an applied water area as a silicon source, and promoting the growth of diatoms present in the applied water area A method for modifying a nutrient environment of a water area, characterized by modifying.
(8) In a water area where phosphorus is excessive, the nutrient composition composition for replenishing water prepared from a mixture of acid-treated rice husk ash treated with nitric acid and crushed shell is supplied to the water area as a silicon source (7) The method for modifying the nutrient environment of the water area described in 1.

Next, the present invention will be described in more detail.
The present invention is a nutrient composition for replenishing water areas to promote the growth of diatoms, which are the preferred microalgae of water areas, and is characterized by blending rice husk ash and calcium carbonate resources as the main components It is what.

  In the present invention, rice husk ash is rice husk ash from agricultural waste or acid-treated rice husk ash obtained by treating it with nitric acid, rice husk ash is rice husk ash from rice husk power generation residue, It is a preferred embodiment that the pulverized calcium source is a crushed shell of seafood, and that the mixing ratio of shell and chaff ash is adjusted to approach 10: 6 by weight. . In this case, depending on the soluble silicon concentration in the material, it is possible to change the mixing ratio slightly.

The present invention also provides a system for producing the above-mentioned nutrient composition for replenishing water areas, by firing a mixture of rice husk ash or acid-treated rice husk ash treated with nitric acid and a pulverized product of a calcium carbonate source. A process for producing a nutrient composition for replenishing water, and a process for producing a liquid fertilizer by neutralizing a waste nitric acid-containing waste liquid discharged at the time of producing acid-treated rice husk ash with CaCO ₃ or shells. It is a feature.

  The present invention also relates to a method for modifying a nutrient environment in a water area, wherein the nutrient composition for replenishing a water area is supplied to an applied water area as a silicon source and promotes the growth of diatoms present in the applied water area. It is characterized by changing to a water environment. In the present invention, it is preferable to supply a nutrient solution composition for replenishment of water prepared from a mixture of acid-treated rice husk ash treated with nitric acid and shell pulverized material to the water region as a silicon source in water regions containing excess phosphorus. This is an embodiment.

  Rice, which is a silicic acid plant, is cultivated all over the world, and is an important agricultural product as a staple food especially in the Asian region, and rice straw, rice husk, etc. are produced as by-products. Among these by-products, rice husk is used for power generation in Thailand, Indonesia, etc. because it can reduce collection costs. However, rice husk contains a large amount of silicic acid, and a large amount of rice husk ash remains after power generation. In addition, shellfish are fished and cultivated around the world, but most of the shells are treated as industrial waste.

  In the present invention, using rice husk ash that is agricultural waste and shells that are aquatic waste, it is to produce a silicon supplement material that changes the nutrient environment of the water area to an environment in which diatoms can easily grow, In this case, the acidic waste liquid discharged is also converted into liquid fertilizer, and a method of using these wastes without any waste is proposed.

The present invention has the following effects.
(1) It is possible to provide a nutrient composition for replenishment of water for replenishing silicon to water by effectively utilizing rice husk ash as agricultural waste and seashell as fishery waste.
(2) The supply of silicon to the water area makes it possible to prepare an environment in which diatoms, which are useful basic producers in the water area, can easily grow.
(3) In this invention, the acid waste liquid discharged | emitted when producing a silicon supply material can also be effectively utilized as a fertilizer.

  EXAMPLES Next, although this invention is demonstrated concretely based on an Example, this invention is not limited at all by the following Examples.

  In this example, rice husks obtained from a farmer in Hiroshima were used as rice husk ash used for rice husk power generation, which was burned in an electric furnace at 900 ° C. for 2 hours. The shells used were oyster shells from Hiroshima. Both were ground with a mortar, pestle and food mixer.

(1) Preparation of acid-treated rice husk ash 10 times the weight of 0.1N-HNO ₃ was added to rice husk ash and left at room temperature for 24 hours, and then the supernatant was removed by centrifugation. Thereafter, it was washed three times with distilled water and dried in an oven at 90 ° C. to produce acid-treated rice husk ash.

(2) Mixing ratio of rice husk ash and oyster shell As the ash and silicic acid (SiO ₂ ) concentration per dry weight of rice husk is 22.5% and 21.8%, silicic acid per rice husk ash The content is 96.9%. The main component of the shell is CaCO ₃ .

It is considered that the chemical reaction when SiO ₂ and CaCO ₃ are mixed and subjected to strong heat treatment is as follows.
CaCO ₃ → CaO + CO ₂
CaO + SiO ₂ → CaSiO ₃ + CO ₂
Therefore, CaCO ₃ + SiO ₂ → CaSiO ₃ + CO ₂
If it is according to this chemical formula, the mixing ratio of shellfish and rice husk ash will be 10: 6 by weight. CaCO ₃ dissociates into CaO and CO ₂ at about 900 ° C. However, the melting point of CaO is 2570 ° C., and the softening point of SiO ₂ (quartz glass) is 1650 ° C. In order to make the reaction proceed completely, the reaction must be performed at a very high temperature. Such a reaction at a high temperature is unrealistic in terms of cost, and it is considered that about 900 ° C. is practical when using heat generated by rice husk power generation or the like.
In this example, these chemical reactions would not progress completely, but the silicon feedstock was made with a mixing ratio of shell and chaff ash of 10: 6 by weight.

(3) Production of silicon supply material Oyster shell and rice husk ash, and oyster shell and acid-treated rice husk ash were mixed well with a small amount of distilled water, placed in a porcelain crucible, and fired at 900 ° C. for 1 hour. After baking, these were milked and ground with a pestle. Material A is a mixture of oyster shell and rice husk ash, and Material B is a mixture of oyster shell and acid-treated rice husk ash. The photographs of rice husk ash, acid-treated rice husk ash, oyster shell, material A and material B are shown in FIG.

As shown in FIG. 1, lower the specific gravity of the apparent rice hull ash by the acid treatment, from about 0.5 g / cm ^3, was slightly compaction to about 0.6 g / cm ^3. In addition, both the fired materials A and B are about 0.6 g / cm ³ , and the apparent specific gravity is almost the same as that of acid-treated rice husk ash, although the weight ratio of shell husk ash is 10: 6. It was about.

(4) Elemental composition of each material and silicon supply material Table 1 shows the elemental composition of the material used in this example. From the table, it can be seen that the concentration of harmful heavy metals (lead, cadmium, chromium) contained in these experimental materials is very low. In particular, the concentration of heavy metals and phosphorus in the rice husk decreased with the acid treatment. Further, the concentration of nitric acid-soluble silicon in the silicon supply material was about 40 mg / g.

(5) Elution experiment 1 of silicon feedstock into seawater
Materials A and B were added to Hiroshima Bay seawater (salt concentration 31.2 psu) at 25 mg / L, shaken at room temperature (about 20 ° C.) for 24 hours, and the elution amounts of heavy metals, phosphorus, and silicon were measured. The results are shown in Table 2. In both materials A and B, the elution of heavy metals was below the detection limit.

  In addition, since the nitrate-soluble silicon present in 25 mg is about 1 mg, most of it was found to elute into seawater within 24 hours. When converted to a molar concentration, 1 mg / L of Si is 35 μmol / L, which is a sufficient silicon concentration (2 μmol / L or more, Non-Patent Document 11) for diatom growth in water.

  On the other hand, in the material A, the elution of phosphorus is 0.08 mg, which is 2.6 μmol / L in terms of molar concentration. Material B must be used when supplying silicon in water where phosphorus is in excess.

(5) Elution experiment of silicon supply material into seawater 2
In a 2L plastic bottle, rice husk ash, acid-treated rice husk ash, crushed shell, fired shell (based on CaO), material A and material B in Hiroshima Bay filtered seawater (initial pH = 8.08, In addition to dissolved inorganic phosphorus (DIP) = 0.80 μmol / L, dissolved silicon (D-Si) = 34.8 μmol / L) at 25 mg / L, a magnetic stirrer at room temperature (about 20 ° C.) The mixture was cultured with stirring, and seawater samples were periodically collected, and the pH, DIP, and D-Si concentrations of the seawater were measured.

  The results are shown in FIG. The pH, DIP, and D-Si concentrations in the figure are shown as differences from the blank experiment. The D-Si concentration eluted immediately after the start of culture with the materials A and B, and the other substances were hardly eluted. Since the concentration of soluble silicon in the materials A and B is about 40 mg / g, 25 mg contains 1 mg (36 μmol) of silicon. About 20% of the soluble silicon was eluted in 20 hours and about 80% was dissolved in one week.

  DIP concentrations of materials A and B were slightly eluted immediately after culturing (5 hours), but were hardly eluted thereafter. Since the concentrations of phosphorus in materials A and B are 1.5 and 0.61 mg / g, respectively, 37.5 μg (1.2 μmol) and 15.3 μg (0.49 μmol) of phosphorus are contained in 25 mg, respectively. It is included. In about 5 hours, about 20% and 32% of the soluble phosphorus was eluted in about 29% and 40% in one week, respectively. In rice husk ash, the phosphorus concentration gradually increased and increased by 0.8 μmol / L in one week.

  The pH of materials A and B increased by about 0.2 immediately after the cultivation (1-5 hours), but was almost constant thereafter. The pH of seawater is easily changed by production using phytoplankton on site. A change of about 0.2 is not considered to be so large as to damage the aquatic ecosystem.

  The elution behavior of silicon and phosphorus in this example is slightly different from the results shown in Table 2. The results in Table 2 are the results of extraction with vigorous shaking for 24 hours, and it is considered that the elution behavior is relatively gentle in the in-situ sea area as in this example.

  As in this example, by using the materials A and B, it is possible to achieve a sufficient silicon concentration (2 μM or more, Non-Patent Document 11) for diatom growth in water. On the other hand, the elution of phosphorus was very small in both cases, but as shown in Table 2, the material A has the potential to elute a large amount of phosphorus, so in the water area where phosphorus is excessive. When supplying silicon, material B must be used.

(7) Use of rice husk ash acid treatment waste liquor Rice husk ash acid treatment uses thin nitric acid. The waste liquid can be easily neutralized with a shell composed mainly of CaCO ₃ . As shown in Table 2, rice hull ash and shells are almost free of harmful metals (lead, cadmium, chromium) and contain some essential trace metals such as iron, zinc and copper. Yes. The neutralization liquid of acid treatment waste liquid contains nitrogen, phosphorus, potassium, and trace metals, and can be used for agriculture as liquid fertilizer.

  As described in detail above, the present invention relates to a composition for silicon supplementation to water bodies using agricultural and marine wastes, etc., and according to the present invention, rice husk ash and marine wastes are agricultural wastes. It is possible to provide a nutritive salt composition for replenishing water to effectively utilize the sea shells and replenish silicon to the water. The silicon supply to the water area makes it possible to prepare an environment in which diatoms, which are useful basic producers of the water area, can easily grow. Moreover, in the present invention, the acid waste liquid discharged when producing the silicon feed material can be effectively used as a fertilizer. The present invention provides a nutritional salt composition for silicon supplementation and a method for altering the water area, which is an important basic producer in the ecosystem of the water area, and makes it an environment in which diatoms, which are useful food for higher-order producers, can easily grow. Useful as something to do.

Photographs of rice husk ash, acid-treated rice husk ash, oyster shell, material A and material B are shown. The result of the elution experiment into the seawater of the silicon supply material (silicon and phosphorus concentrations in seawater, pH value) is shown.

Claims (8)

  Nutrient composition for supplementing silicon to replenish water in order to promote the growth of diatoms, which are the preferred microalgae in the water area, and the nutrition for replenishing water that contains rice husk ash and pulverized calcium carbonate resources as the main components Salt composition.   The nutrient composition for water supply according to claim 1, wherein the rice husk ash is rice husk ash from agricultural waste or acid-treated rice husk ash obtained by treating the rice husk ash with nitric acid.   The nutrient composition for water supply according to claim 1, wherein the rice husk ash is rice husk ash of rice husk power generation residue.   The nutrient composition for replenishing water according to claim 1, wherein the pulverized product of the calcium carbonate source is a crushed shell of shellfish.   The nutrient composition for replenishing water according to claim 1, wherein the mixing ratio of shellfish and rice husk ash is adjusted to approach 10: 6 by weight. A system for producing a nutrient composition for replenishing water according to any one of claims 1 to 5, wherein a mixture of acid-treated rice husk ash treated with rice husk ash or nitric acid and a ground product of a calcium carbonate source is calcined. From the process of producing a nutrient composition for water replenishment and the process of producing liquid fertilizer by neutralizing the waste liquid containing nitric acid with a low concentration discharged during the production of acid-treated rice husk ash with CaCO ₃ or shells A manufacturing system of a nutrient composition for replenishing water.   The nutrient composition for replenishing water according to any one of claims 1 to 5 is supplied to a water area as a silicon source, and the water environment is modified to promote the growth of diatoms present in the water area. To modify the nutrient environment of the water area.   The water area according to claim 7, wherein in the water area where phosphorus is excessive, a nutrient composition composition for replenishing water area prepared from a mixture of acid-treated rice husk ash treated with nitric acid and crushed shell is supplied to the water area as a silicon source. To modify the nutrient environment