Abstract

Patinopecten yessoensis) without separating the midgut gland. That is, a small amount of an aqueous citric acid solution is added to the processing residues of scallop including the midgut gland in which cadmium has been accumulated at a high concentration and the mixture of them is heated to 55 to 65° C. Thus, the thin midgut gland membrane is broken and the internal solution of the midgut gland containing cadmium is eluted. Then, solid matters are separated from the mixture including the solid matters and the internal solution of the midgut gland eluted. As the aqueous citric acid solution, a solution prepared by mixing at least 9% by weight of water relative to the processing residues and 1.8 to 3.3% by weight of citric acid relative to the total weight of the processing residues and water is used. The content of cadmium in the solid matters can be further reduced by adding water to the solid matters having been separated and then heating the mixture of them to 55 to 65° C., thereby washing off cadmium remaining in the solid matters.

IPC Classes  ?

• A23K 1/10 - from meat, fish, or bones; from kitchen waste
• C05F 1/00 - Fertilisers made from animal corpses, or parts thereof

Abstract

From processing residues of scallop (Patinopecten yessoensis), cadmium is removed without separating the midgut gland and thus an organic fertilizer and an organic feed are produced. To the processing residues of scallop including the midgut gland in which cadmium has been accumulated at a high concentration, a small amount of an aqueous citric acid solution is added and the mixture is heated to 55 to 65°C. Thus, the thin midgut gland membrane is broken and the internal solution thereof containing cadmium is eluted. From the liquid mixture comprising solid matters and the internal solution of the midgut gland thus eluted, the solid matters are separated. As the aqueous citric acid solution, a solution prepared by mixing at least 9 wt%, relative to the processing residues, of water with 1.8 to 3.3 wt%, relative to the total weight of the processing residues and water, of citric acid is used. The cadmium content of the solid matters can be further reduced by adding water to the solid matters having been separated and then heating the mixture to 55 to 65°C to thereby washing off cadmium remaining in the solid matters.

IPC Classes  ?

• C05F 1/00 - Fertilisers made from animal corpses, or parts thereof
• A23K 1/10 - from meat, fish, or bones; from kitchen waste
• B09B 3/00 - Destroying solid waste or transforming solid waste into something useful or harmless

Abstract

An aqueous acetic acid solution is added to a product of pulverization of a cadmium-containing leftover resulting from marine product processing. This mixture is heated and the liquid is separated to obtain a residue. This step is conducted repeatedly to reduce the cadmium concentration based on nitrogen to a value not higher than an allowable limit. The final residue having such a reduced cadmium concentration is used as a fertilizer. A liquid fertilizer may be obtained from the liquid separated in this step, by concentrating the liquid under vacuum to obtain a concentrate, adding an aqueous sulfide solution to the concentrate, stirring themixture, subsequently adding a coagulant thereto, and neutralizing the resultant supernatant.

IPC Classes  ?

• C05F 1/00 - Fertilisers made from animal corpses, or parts thereof
• C05G 5/00 - Fertilisers characterised by their form