Application of Swirling Jet Mixing to Cadmium Extraction from Guts of Scallop

Abstract

Removal of cadmium in guts of scallop is one of serious problems in the northern part of Japan. The guts cannot be discarded as well as used as food, feed, and fertilizer unless the cadmium is removed from them. We have developed a swirling jet mixing method having high mixing efficiency and simple structure for wastewater treatment and snow melting. In this study, we applied this mixing method to cadmium extraction from the guts of scallop. HCl aqueous solution of pH=1.0∼2.0was used for the cadmium extraction. Small-scale and medium-scale tests were carried out using boiled no-cut guts by the swirling bubbling jet mixing method. More than 98% of the cadmium contained in the guts was extracted. The extraction rate was higher than that in the shaking test. The cadmium concentration in the treated guts cleared the acceptable cadmium level in food in Japan.