Youichi Sakuta*, Keiichi Tomita*, Motoomi Wakasugi*, Takayuki Saito* and Nobuhiro Nagano*

* Hokkaido Industrial Research Institute

+ Correspondence should be addressed to Youichi Sakuta:
(Kita 19-jo, Nishi 11-chome, Kita-ku, Sapporo 060-0819 Japan)

Abstract

The removal of cadmium from the waste products of scallop processing was examined. In Hokkaido, the production of scallops has been increasing annually, and waste product appears to be increasing in proportion to the processing volume. Because the waste products of scallop, especially the mid-gut gland, contains a large quantity of heavy metals, such as cadmium, effective use is impossible. Studies of cadmium distribution in various tissues which were made during each of the seasons showed that the concentration of cadmium is the highest in the mid-gut gland and the increases in accordance with the growth of the animal. Cadmium can be removed by one process as described below. (1) The mid-gut gland is soaked in a dilute sulfuric acid solution which dissolves the cadmium. (2) When an electric current is passed through the solution, the cadmium is deposited on the cathode surface. Treatment using the above method removed more than 90% of the cadmium from the mid-gut gland. After the removal of cadmium, the dried and crushed wastes products of the scallops were used as feed and fertilizer materials.

Key words: mid-gut gland of scallop, cadmium, removal technology, feed and fertilizer, electrodeposition