JP2003023889A - Method for treating laver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for removing various algae such as diatoms by carrying out washing of laver or a laver net at a relatively high pH by using a treating liquid containing no or a remarkably reduced amount of an organic acid or an organic substance adversely affecting the natural environment in culturing the laver. SOLUTION: An acid solution containing an inorganic oxide, an inorganic peroxide, ferric chloride or ferric sulfate is diluted with seawater and regulated to pH 2-2.5. The resultant regulated solution is then brought into contact the laver or laver net.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to the treatment of seaweed which removes slimes and algae, mainly diatoms, adhering to seaweed and seaweed nets during cultivation and prevents diseases such as red rot and white rot. It is about the method.

[0002]

2. Description of the Related Art Nori seaweed and seaweed nets during aquaculture adhere to the algae that grow in seawater, mainly diatoms, which not only deteriorates the quality of the seaweed but also hinders the operational management of the seaweed culture. ing. Therefore, an acid treatment agent is used to remove such diatoms. Organic acids are often used as acid treatment agents at present, and a dilute solution of malic acid, citric acid, acetic acid or the like or a solution prepared by dissolving fertilizer or the like is mixed with an acidic solution. Examples of methods using these organic acids include JP-B-56-12601, JP-B-60-31451, and JP-B-60-31647.

[0003]

The above-mentioned cleaning with an organic acid has the following problems. In other words, diatoms have a very high calcium content when compared to their analytical values,
Next, the contents of iron and silicon are very large. It is difficult to remove deposits such as calcium salt from organic acid on the surface of seaweed. Further, although the permeability is good, it is difficult to remove the permeated organic acid. Further, in order to remove undesired algae such as diatoms and prevent diseases such as red rot, the treatment time is 5 to 60 minutes, and a short treatment time is 3 to 30 minutes, which is a relatively long time. This is a batch process in which the seaweed net is pulled up on the ship and immersed in the treatment solution, and then the seaweed net is returned to the sea again. There were few. Therefore, recently, a special ship called a moguri ship has been developed and used, in which the ship is dipped under the seaweed net and the treatment liquid is brought into contact with the seaweed net for processing. In this case, since the contact time between the seaweed net and the treatment liquid is as short as 20 to 60 seconds, it is necessary to select a low pH range. For example, it is desirable to select pH = 0.5 to 1.5.

In this method, in order to use an organic acid and lower the pH, it is usually necessary to make the concentration of the organic acid, which is characterized by a high pH region, to be high. To do. That is, compared to inorganic acids, C
It greatly affects OD and BOD, and when washing nori and nori nets, a large amount of organic acid flows into the sea as waste liquid, and when mixed with seawater, biodegradation occurs by microorganisms, but
At the same time, the BOD is increased in seawater, and a eutrophication phenomenon occurs. As is well known, drainage containing nutrients flows into the inner bays, causing plankton to multiply and become oxygen deficient, resulting in water pollution (in the Ariake Sea, seaweed was killed by lack of oxygen). Therefore, wastewater containing organic matter has high COD or BOD, and the Environmental Agency regulates discharge according to wastewater standards. Especially in the inland sea such as the Seto Inland Sea, the drainage water discharged from the surrounding factories is regulated one order higher than the regulation value by law. By the way, when the products using malic acid and citric acid as organic acids were used and hydrochloric acid was used as an inorganic acid, and the CODs when these were diluted 100-fold, the organic acid was about 3000 mg / l. In contrast, the inorganic acid is about 4
It is 0 mg / l.

In addition, the method using the above-mentioned mogul vessel, that is, a washing tank is provided on the hull, the net to be treated is lifted up and the hull is moved under the net, and at that time, the washing liquid in the washing tank is circulated by a pump. It is continuously washed by spraying it on the mesh surface, collecting the collected liquid in the cleaning tank, adjusting the pH to about 2 and circulating it, but the waste liquid collected after use is neutralized. PH is adjusted to 5.8 to 8.6 and discharged as sewage into sewage. When an organic acid is used, COD and BOD are high even if neutralized, and activated sludge treatment or the like is required. In the case of an inorganic acid, for example, when hydrochloric acid is used, it is discharged as waste water without being affected by COD and BOD, since salt is produced by neutralizing with sodium hydroxide. In the sea area, drainage is discharged within the range of pH = 5-9.

[0006] In view of the above points, the present invention, in the cultivation of seaweed, without adversely affecting the human body and the natural environment,
It can be used stably in a relatively high pH range at low cost, and the concentration of COD and BOD, which has an adverse effect on the environment, can be drastically reduced even if an organic acid is used, because the added amount is small. It is an object of the present invention to provide a method for treating seaweed, which enables efficient removal of slime or other algae such as diatoms and preventive treatment of diseases.

[0007]

According to the present invention, slime adhered to laver and laver nets using an acid solution containing an inorganic oxide, an inorganic peroxide, ferric chloride and / or ferric sulfate. A method for treating seaweed is provided, which comprises removing undesired algae such as diatoms. Further, an acid solution containing an inorganic oxide, an inorganic peroxide, ferric chloride and / or ferric sulfate,
A method for treating seaweed, which comprises diluting with seawater or water to adjust the pH to 2 to 2.5, and contacting the seaweed and the seaweed net to remove slime, diatoms, and other algae attached to them. Will be provided. There is also provided a method for treating seaweed, wherein the inorganic oxides are hypochlorous acid, chlorine dioxide and potassium permanganate, and the inorganic peroxides are hydrogen peroxide, potassium persulfate and ammonium bisulfate.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION To carry out the present invention, an inorganic acid or an organic acid is added to an aqueous solution of an inorganic oxide, an inorganic peroxide, ferric chloride and / or ferric sulfate, and pH = 1. .. Prepare a solution adjusted to 5 or less and fill it in a container such as a cucumber retainer to prepare a seaweed treatment solution (stock solution). As the inorganic acid, hydrochloric acid, phosphoric acid and the like are preferable, and hydrochloric acid is particularly preferable. Examples of the organic acid include malic acid, citric acid, acetic acid and the like. When using an inorganic oxide, an inorganic peroxide, ferric chloride, or ferric sulfate, a preferable content is 1 to 10% by weight. This treatment liquid is introduced to the washing tank on board the ship, and about 100 to 100
Diluted 200 times, and pH = 2 depending on the treatment liquid before dilution.
Adjust to 2.5 to make a cleaning solution.

[0009] On the other hand, the seaweed and the seaweed net with slime, diatoms and other algae adhering to them are lifted up and the hull is dipped under the seaweed, and the seaweed is cut to a substantially constant length by a cutter on the ship. After that, it is guided to the washing tank installed in the hull. In the washing tank, the laver net after washing is wound up by the power, so that the laver and the laver net are soaked in the washing liquid diluted with seawater to proceed. According to another method, the seaweed net after cutting the seaweed is passed through the cleaning tank provided on the hull as described above, the cleaning liquid is pumped up and sprayed on the top of the seaweed net to wash it, and the The liquid is returned to the washing tank and circulated. A pH meter is installed in the outlet path of the pump, and the pH value of the pump outlet is automatically controlled by the pH meter by using the processing liquid before dilution. Can be set arbitrarily.

[0010]

EXAMPLES The present invention will be described below with reference to examples. The composition% in each example is% by weight. Example 1 To 700 ml of water, 200 ml of 30% hydrogen peroxide aqueous solution was added, 58 ml of 35% hydrochloric acid and 4 ml of phosphoric acid were added to this solution, and water was further added to adjust to 11 to obtain a treatment liquid having pH = 0.1. Seawater was added to 10 ml of this treated solution to dilute it to 11 (100-fold diluted solution) to prepare a washing solution having a pH of 2.34. The content of hydrogen peroxide in the cleaning liquid is 0.06%, and the content of hydrochloric acid is 0.023%. The seaweed with red rot and the seaweed with slime were collected in advance and cultivated in a laboratory water tank (constant temperature tank) in which the temperature was adjusted to 10 ° C by circulating seawater. The 11 washing solutions prepared above were divided into two to prepare two 500 ml solutions. Next, 50 g of each seaweed sample was taken out from the water tank, allowed to act on this solution for 60 seconds and returned to the original water tank, and after 3.5 hours, it was observed using a microscope. The slime adhering to the seaweed was removed and activation occurred on the surface of the seaweed. A test was also conducted on a sample to which diatoms adhered by the same operation, but the diatoms were removed and good results were obtained.

Example 2 While stirring 700 ml of water, 50 g of potassium persulfate was added and dissolved, 290 ml of 35% hydrochloric acid was added to this solution, and water was further added to adjust to 11 to obtain a treatment liquid. This processing liquid 1
Seawater was added to 0 ml to dilute it to 11 to prepare a washing solution having a pH of 2.03. When the same test as in Example 1 was conducted using this cleaning solution, good results were obtained as in Example 1.

Example 3 To 12 ml of a 47.5% ferric chloride aqueous solution, 100 ml of citric acid was added.
g, 14.5 ml of 35% hydrochloric acid, and then water
It was adjusted to 1 to obtain a treatment liquid having a pH of 1.05. Seawater was added to 10 ml of this treatment liquid to dilute it to 11 to prepare a cleaning liquid having a pH of 2.05. The content of ferric chloride in the cleaning liquid is 0.06%, and the content of citric acid is 0.1%. When the same test as in Example 1 was conducted using this cleaning solution,
Good results were obtained although slightly inferior to Example 1.

[0013]

EFFECTS OF THE INVENTION According to the present invention, in the cultivation of seaweed, it is possible to eliminate or significantly reduce the organic acid or organic matter in the treatment liquid used for washing the seaweed and the seaweed net, so that the marine pollution can be reduced. It is useful for preventing and protecting the natural environment.
Further, since slime or diatoms and other miscellaneous algae can be efficiently removed in a relatively high pH range, it is possible to perform stable operation without the need to raise the acidity of the cleaning liquid. This is particularly advantageous when washing is performed continuously.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideki Kasai             2-5-2 Muromachi, Matsuyama City, Ehime Prefecture

Claims (3)

[Claims] 1. Use of an acid solution containing an inorganic oxide, an inorganic peroxide, ferric chloride and / or ferric sulfate to remove slime, diatoms and other algae attached to laver and laver nets. A method for treating seaweed characterized by: 2. Nori and nori prepared by diluting an acid solution containing an inorganic oxide, an inorganic peroxide, ferric chloride and / or ferric sulfate with seawater or water and adjusting the pH to 2-2.5. The method for treating seaweed according to claim 1, wherein the method comprises contacting with a net. 3. The inorganic oxide is hypochlorous acid, chlorine dioxide,
Potassium permanganate, inorganic peroxide is hydrogen peroxide,
The potassium persulfate or ammonium sulphate as claimed in claim 1 or 2.
The method for treating nori described in.