Study on Neutralization of Tamagawa Acidic Water Using Iron and Steel Slags

The Tamagawa acidic water originates from the Tamagawa hot springs in eastern Akita Prefecture. Currently, the pH of Lake Tazawa has increased from 4.6 to about 5.8 due to the operation of a neutralization treatment facility. However, it has not recovered to 6.8, and the water environment and ecosystem have not yet recovered. In this study, a neutralizer was prepared four kinds of iron and steel slag for using to improve Tamagawa acidic water and to expand the use of them. Neutralization experiments were conducted to evaluate the effectiveness of the neutralizer by analyzing pH changes and concentration of several metal ions about treated water and surface composition of used neutralizer. The results showed the pH of acidic water was raised by these neutralizers, and did not leach heavy metal ions, suggesting that the neutralizer could be used stably.