Abstract
The use of a suspended growth system of t. Ferrooxidans attached in a film to individual particles of bentonite and operated as a sequencing batch reactor has proved to be a practical way of oxidizing ferrous iron in acid mine drainage. This component, followed by limestone neutralization, is both a technically and economically feasible approach to the treatment of these wastewaters in comparison with existing and proposed methods. The advantages, in addition to less expense, are greater safety, acceptable treatment at a lower ph, lower solids buildup, less danger of overtreatment, and greater flexibility in operational characteristics. In this report, data on the continuous bench-scale operation of the system under a variety of conditions show sustained levels of oxidation in excess of 95 pct.