RESEARCH ON PROCESS INTEGRATION OF THE BACTERIAL OXIDIZATION AND THE NEUTRALIZATION PARTS FOR ACID MINE DRAINAGE TREATMENT

摘要

Acid mine drainage of abandoned Matsuo Mine in Japan has been treated with bacterial oxidization, because of high contents of Fe (II) and calcium carbonate neutralization since 1982. The present process of the treatment plant consists of the oxidization part, the neutralization part, and other utilities. The mine drainage of pH 2.2-2.3 is treated to be pH 4.0-4.2 in the plant. In this research, active scale experiments were done to integrate the oxidization part and neutralization part to make the facility more simple and energy-efficient. Oxidizing tank was used for bacterial oxidization and calcium carbonate charge to control the pH 4.0 level simultaneously. As a result of the experiment, by separating the oxidizing tank to eight parts and to precipitate calcium carbonate at four selected points, it is confirmed that; - it is possible to treat 9m~3/min AMD, as same as present treatment volume, to be pH4 while maintaining the vitality of bacteria, bacteria multiply rapidly in the combined tank, in which oxidization and neutralization occur, and accelerate iron oxidization, - recycle of bacteria sludge with appropriate conditions is effective to keep the bacteria vitality and sludge density in the combined tank. Keywords: Acid rock drainage, pH control, Bacteria, Environment, Pollution