Abstract: Contaminated water flowing from abandoned coal mines is one of the most significant contributors to water pollution in former and current coal-producing areas. Acid mine drainage (AMD) can have severe impacts to aquatic resources, can stunt terrestrial plant growth and harm wetlands, contaminate groundwater, raise water treatment costs, and damage concrete and metal structures. In the Appalachian Mountains of the eastern United States alone, more than 7,500 miles of streams are impacted. The Pennsylvania Fish and Boat Commission estimates that the economic losses on fisheries and recreational uses are approximately $67 million annually (ref). While most modern coal-mining operations (Figure 1) must meet strict environmental regulations concerning mining techniques and treatment practices, there are thousands of abandoned mine sites in the United States (Figure 2). Treatment of a single site can result in the restoration of several miles of impacted streams. The purpose of this document is to briefly summarize key issues related to AMD treatment. This document is intended as a brief overview; thus, it is neither inclusive nor exhaustive. The technical note presents the preliminary planning issues

Abstract: Acid ground waters contaminated with radioactive elements (U, Ra, Th), toxic heavy metals (Cu, Zn, Cd, Mn, Fe), arsenic and sulphates were treated by means of a permeable barrier. The barrier was filled with a mixture of biodegradable solid organic substrates (spent mushroom compost, sawdust and cow manure) and was inhabited by a mixed microbial community consisting of sulphate-reducing bacteria and other metabolically interdependent microorganisms. An efficient removal of the pollutants was achieved by this barrier during the different climatic seasons, even at ambient temperatures close to degrees C. The microbial dissimilatory sulphate reduction and the sorption of pollutants by the organic matter in the barrier were the main processes involved in this removal.