The acid mine drainages (AMD) are treated by neutralization with the two problems: (1) an enormous expenditure; and (2) a discharge of neutralization sludge. In this context, as a case study, a novel remediation method was applied for AMD at Horobetsu mine. The schwertmannite is generated by iron-oxidizing bacteria with Fe<SUP>2+</SUP> and SO<SUB>4</SUB><SUP>2-</SUP> in acidic mine waters. Its efficiency in As uptake through sorption has been documented in the natural attenuation in Nishinomaki. This study demonstrates the advantages and feasibility of utilizing schwertmannite as a novel re...