JP2002233863A - Method for treating waste water of hard roe seasoning liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for treating waste water of a seasoning liquid to such a degree that it can be subjected to biological treatment as general waste water treatment. SOLUTION: 1) Waste water of a seasoning liquid is poured into a reaction vessel having pH adjusting function, sludge of biological treatment, aluminum sulfate and aluminum polychloride are added, an alkali agent such as sodium hydroxide, sodium carbonate or sodium bicarbonate is added to adjust the waste water to a very low acidity of pH 6.0±0.5 and sodium polyacrylate or a hydrolyzate of polyacrylamide as an anionic polymer flocculant is added to cause flocculation. 2) Hard flocks are formed by the above method and separated by floatation or precipitation as an ordinary separating operation, the treated water is biologically treated and the separated scum or precipitate is mixed with sludge of biological treatment and dehydrated.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating wastewater after use of a seasoning solution for fish eggs such as salmon sprouts. 2. Description of the Related Art Waste water after use of a seasoning solution for fish eggs has a BOD of 300,000 or more and is unsuitable for biological treatment which is a usual waste water treatment method, and has a strong salt content, is acidic, and has a fat and oil component. Because of this, simple coagulation treatment was not possible, and strong primary cohesion did not occur due to the effects of salts, oils and fats, and protein hydrolysates, so simple primary treatment was not possible.Conventionally, it was carried out in a vacuum car and disposed of as waste. . For this reason, waste disposal costs became a heavy burden on fish egg processing plants. An object of the present invention is to provide a method of treating seasoning liquid wastewater to such an extent that the seasoning liquid wastewater can be subjected to a microorganism treatment method which is a general wastewater treatment method. Means for Solving the Problems The present inventor has focused on the components of the drainage of the seasoning liquid, such as salts, fats and oils, and protein hydrolysates, which are considered to prevent coagulation. As a result, an inorganic coagulant such as a sulfuric acid band, polyaluminum chloride, and iron chloride was added to the drainage of the seasoning liquid having an acidity of pH 4 to 5, and the pH was adjusted with an alkaline agent such as sodium hydroxide and sodium carbonate.
Is adjusted to 6 ± 0.5 and flocculated with an anionic flocculant, or a biologically treated sludge is added to the drainage of the seasoning solution, and then a cationic polymer flocculant is added, and then a sulfate band or polyaluminum chloride, etc. And the pH is adjusted to 6 with an alkaline agent such as caustic soda and sodium carbonate.
A method of adjusting to ± 0.5 and coagulating with an anionic polymer coagulant. Seasoning liquid drainage, which was conventionally regarded as difficult to coagulate, forms a strong coagulated floc by these methods and coagulates,
The flocculated floc is separated by flotation separation, sedimentation separation, etc., and the treated water is subjected to biological treatment, and the floatation sediment (floating scum) or sediment is mixed with biological treatment sludge and then dewatered. In the present invention, as an alkaline agent used as a pH adjusting agent important for coagulation of a seasoning solution which is conventionally acidic, not only a strong alkaline agent such as caustic soda, but also a great feature that a weak base such as sodium carbonate can be used, For this reason, the processing work was facilitated and the danger was eliminated. This is because after addition, the metal ions of the inorganic flocculant such as the sulfate band or polyaluminum chloride are combined with the organic acid contained in the fat and oil decomposed product or the protein hydrolyzate in the seasoning liquid, thereby lowering the degree of ionization. Although the added inorganic flocculant is acidic, the pH can be easily adjusted by adding an inorganic flocculant such as a post-sulfuric acid band or polyaluminum chloride, rather than adjusting the pH with a single alkali agent. For this reason, the consumption of the alkali agent is reduced, and the operation cost is reduced. In an actual treatment device, the seasoning liquid wastewater is allowed to flow into a reaction tank controlled by a control device having a pH adjusting function, and after adding a sulfuric acid band and polyaluminum chloride, caustic soda,
Add sodium carbonate or sodium bicarbonate alkaline agent
H is adjusted to slightly acidic of 6.0 ± 0.5, and sodium polyacrylate and polyacrylamide hydrolyzate, which are anionic polymer coagulants, are added and coagulated, followed by dehydration treatment or pressure flotation. To separate. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 1 is a flow sheet according to an embodiment of the present invention. [0006] The method of the present invention has the following advantages over the conventional waste treatment. (1) According to the method of the present invention, it is possible to treat at the site where the seasoning liquid wastewater is generated, which has been conventionally difficult in the wastewater treatment step, and the cost of waste treatment is greatly reduced. (2) The method of the present invention has a small number of difficult parts and can be configured as an extremely easy-to-adjust processing apparatus, and thus has a wide range of applications.
For this reason, the size of the processing equipment can cope with business types in which the amount of generated wastewater, such as processing plant wastewater, varies greatly. (3) Since the method of the present invention can be easily added to the ordinary factory wastewater treatment step and the sludge dewatering step of microbial treatment, the treatment step can be easily incorporated into an existing factory. Example 1 Myosin seasoning liquid BOD320,000 ppm20
After adding 50 ml of biologically treated sludge having a concentration of 5000 ppm to 0 ml, adding 2 ppm of a cationic polymer flocculant and 150 ppm of polyaluminum chloride, the pH is adjusted to 6.0 with caustic soda.
After that, 6 ppm of an anionic polymer flocculant was flocculated and separated, and the precipitate formed a strong floc. The clear BO
D became 1/3 at 130,000 ppm. [Example 2] Drainage BOD 3000ppm40 of fish egg processing plant
0t, continuous addition of BIO320,000ppm15t, 5t of biologically treated sludge having a concentration of 5000ppm to 0t, addition of 5ppm of a cationic polymer flocculant and 150ppm of polyaluminum chloride, pH 6.0 with sodium carbonate, and anionic polymer flocculant 12 ppm was added to carry out coagulation separation, and the flotation product formed a strong floc. As a result of the pressure flotation separation, the treated water became 4500 ppm, and the treated water treated by the batch biological treatment became 50 ppm.

[Brief description of the drawings] FIG. 1 is a flow sheet of the method of the present invention.

Claims (1)

Claims: 1. A drainage of a pickling solution used for seasoning a fish egg (hereinafter referred to as a seasoning solution drainage) is mixed with a factory drainage, and a sulfuric acid band and polyaluminum chloride are added.
The pH was adjusted to 6.0 ± 0.5 by adding an alkali agent of sodium carbonate and sodium bicarbonate, and an anionic polymer flocculant such as sodium polyacrylate and hydrolyzed polyacrylamide was added to cause aggregation. Wastewater treatment method of pressure flotation and separation. 2. The method of claim 1, wherein when the wastewater of the seasoning liquid is mixed with factory wastewater, sludge from a biological treatment aeration tank is added and mixed, and then a sulfuric acid band and polyaluminum chloride are added. The pH is adjusted to 6.0 ± 0.5 by adding an alkali agent of sodium bicarbonate, and an anionic polymer coagulant such as sodium polyacrylate or hydrolyzed polyacrylamide is added to cause coagulation. Wastewater treatment method with pressure flotation. 3. Addition of biological treatment aeration tank sludge, sulfate band, and polyaluminum chloride only to the drainage of seasoning liquid, and then addition of caustic soda, sodium carbonate, and sodium bicarbonate alkaline agents to adjust the pH to 6.0 ± 0.5. A wastewater treatment method in which sodium acrylate and polyacrylamide hydrolyzate, which are anionic polymer coagulants, are adjusted and coagulated, followed by dehydration treatment or flotation under pressure. 4. A seasoning characterized by mixing the floating scum which has been agglomerated and separated by pressure flotation with the biologically treated sludge and dewatering treatment. Dehydration method for liquid aggregates