JPS5874192A - Treatment for waste of processed marine products - Google Patents

Abstract

PURPOSE:To prevent the generation of malodors and to obtain dry bacterial fertilizers by subjecting a mixture of the blood juice produced in the stage of cooking raw material fishes in processing of marine products and the floating froth produced in treatment of waste liquid to anaerobic treatments thereby generating gaseous methane. CONSTITUTION:The mixture (a) of the blood juice produced in the stage of cooking of raw material fishes stored temporarily in a receiving tank 1 and the floating froth produced in treatment of waste liquid is transferred into the hesinetically closed 1st digesting tank 2, and is further transferred into the 2nd digesting tank 3. In the respective digesting tanks, the mixture is anaerobically digested. If in this case, the anaerobic digesting treatment is performed by maintaining the respective digesting tanks at 30-40 deg.C, org. materials are decomposed and digested in the tanks 2, 3 and digesting gases contg. 60-70% gaseous methane which is an essential component are produced. The desorbing liquid discharged from the upper part of the tank 3 is fed to an activaged sludge aerating tank 8, where the liquid is subjected to a biological oxidation treatment. The excess sludge thereof is dried under reduced pressure in a dryer 9 and is made into dry bacterial fertilizers 10.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating marine product processing waste, and more specifically to a treatment method that is extremely effective in terms of pollution prevention and energy conservation.

Conventionally, in processing plants such as seafood canning, there was no effective treatment method for waste such as blood juice generated during the cooking process of raw fish and floating floss generated from waste liquid treatment, so they either carried out condensation treatment or I was in the process of disposing of it. However, in the case of thinning treatment, the treatment cost continues to increase due to the recent rise in the price of heavy oil, and in the case of disposal treatment, there are various problems such as causing foul odor and pollution.

By the way, methane fermentation treatment methods that generate methane gas that can be used as fuel have been put to practical use in the treatment of sewage sludge, human waste, and livestock manure. In the case of processing,
Since it contains a large amount of oil and fat, it was thought that such methane fermentation treatment would be difficult. However, if marine product processing waste could be sufficiently decomposed by methane fermentation treatment to generate methane gas, it would be more desirable in terms of energy saving and prevention of odor pollution.This invention was made in view of the above circumstances. By anaerobically digesting the mixture of blood juice produced during the raw material fish cooking process and floating cloth produced during waste liquid treatment, it is possible to convert the mixture into methane gas, thereby saving energy and preventing odor pollution. K.

I've been busy trying to get some dry boxed fertilizer.
``With reference to FIG. 1, which shows a preferred embodiment,
The processing method of this invention will be explained in detail.

In Fig. 1, l is a receiving tank, and the blood juice and floating liquid are initially temporarily combined and stored in this receiving tank l.As mentioned above, the blood juice is a waste product generated in the raw fish cooking process. Floating floss, which contains a large amount of internal organs extracted from raw fish, is used in the treatment of waste liquid from seafood processing to separate waste liquid from coarse solids and crude oil into a pressurized flotation separator. It comes to the surface during processing and consists of fine solids and fats and oils.

In this way, the mixture a of blood juice and floating floss temporarily mixed and stored in the receiving tank l is then transferred to the sealed first digestion tank 2.
and further transferred to the second digestion tank 3, where they are subjected to anaerobic digestion treatment. This anaerobic digestion treatment is carried out by the action of methane atomization and acid bacteria that are generated and proliferated in the first and second digestion tanks 2.3.
When only floating floss containing a large amount of oil and fat is subjected to anaerobic digestion, the oil and fat are decomposed and digested by the action of these bacteria, and K<r, so that a satisfactory treatment cannot be achieved. However, when blood juice is mixed in the flotation floss as in this invention, the internal enzymes of the fish contained in the blood juice promote the decomposition of oil and fat, so the plane works actively, and the blood juice and flotation floss are mixed. It quickly digests the organic matter inside and generates digestive gas, the main component of which is methane gas. Therefore, in this anaerobic treatment, it is desirable to maintain the mixture of blood juice and floating floss at a temperature between 3Q and 40°C, where the decomposition promoting effect by visceral enzyme llK is large and the action is active. . Therefore, in the embodiment shown in FIG.
It is kept warm in the temperature range of 30° to 400C.

When anaerobic digestion is performed in such a temperature range, the mixture remains in both the digestion tanks 2 and 3 for a total of about 25 to 40 days. ■Just add most of the liquid to the mixture.

All organic matter is decomposed and digested, and the digestive gas contains approximately 60-75% of the main component, methane gas (excluding the methane gas, most of the remainder is carbon dioxide).The amount of this digestive gas generated is, for example, 12 m' When a mixture (V material content: 800 kg) is subjected to anaerobic treatment under the above conditions, the length is approximately 800 m''.

This anaerobic digestion process is particularly efficient when the raw fish is sardines or mackerel.

All of the digestion gas b generated in the digestion tank 5 may be taken out, but in the embodiment shown in FIG. It is used for bubbling and mixing and stirring of materials. Digestion gas taken out midway without being returned to the digestion tanks 2, 3 is passed through desulfurizers 5, 5, where sulfur compounds that cause boiler corrosion etc. are removed, and then retained in a gas holder 6. The digestion gas with a methane gas content of about 60 to 75% retained in the gas holder 6 is used to heat the boiler 7, and the generated steam is transferred to the aforementioned digestion tank "2.
On the other hand, the separated liquid taken out from the upper part of the second digestion tank 3 is sent to the activated sludge aeration tank 8, and is used for preheating boiler water used in the factory. The floating floss is subjected to biological oxidation treatment together with the waste liquid after flotation separation.The excess sludge taken out from the activated sludge aeration tank 8 is separated by sedimentation, dehydrated and sent to the sludge dryer 9, and then Using the heat of the steam supplied from the boiler 7, it is dried and assimilated under reduced pressure to become dry bacterial fertilizer lO.

In addition, the digested sludge taken out from the lower part of the second digestion tank 3 has extremely low organic matter content and has good dewatering properties, so it is sent to the dehydrator 11 and vacuum dehydrated before being disposed of in a landfill. . Even if it is disposed of in a landfill, there is no risk of causing odor pollution because it contains almost no organic matter.

As is clear from the above explanation, the method for treating seafood processing waste of the present invention uses blood juice containing visceral enzyme tubes that promote the decomposition of fats and oils for floating floss containing a lot of fats and oils, which is difficult to anaerobically digest. By mixing, the methane garden and acid bacteria are activated, making anaerobic digestion possible, and the resulting digestion gas, whose main ash is methane gas, is used as thermal energy. It achieves the following effects: it saves energy by saving heavy oil, prevents bad odor pollution, and also provides high-quality dried bacterial fertilizer.

In the embodiment shown in FIG. 1, the first digestion tank 2 and the second digestion tank 3 are
Although we have shown the case where a two-stage digester with all attached tanks is used, a single-stage digester may also be used, and in some cases, the broth produced in the steaming process of seafood processing may be further added to the mixture and treated in the same way. OK to do 0

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of an embodiment of the present invention.・Desulfurizer, 6... Gas holder, 7... Boiler, 8... Activated sludge aeration tank, 9... Sludge dryer, lO... Dry bacterial fertilizer, ll
... Dehydrator, a... Mixture, b... Digestion gas. Patent applicant: Oshinozu Food Industry Co., Ltd. Agent
Mihiko Watanabe

Claims (1)

[Claims] Processing of seafood processing waste characterized by anaerobically digesting a mixture of blood juice produced in the fish cooking process and floating floss produced in waste liquid treatment to generate digestive gas mainly composed of methane gas. Method 0