Passive Treatment of Acid Mine Drainage

Abstract

Acidic mine drainage (AMD; also called “acid rock drainage” or “acid drainage”) is an environmental pol-lutant that impairs water resources in mining regions throughout the world. Where such treatment is required legally, treatment must be efficient and continual. Treatment methods are commonly divided into either “active,” meaning reliance on the addition of alkaline chemicals to neutralize the acidity, or “passive.” The term “passive treatment” means reliance on biologi-cal, geochemical, and gravitational processes. Passive treatment does not require constant care or the chemi-cal reagents that characterize “active” AMD treatment. This publication presents guidance for design of pas-sive treatment systems for AMD. Our emphasis is to describe clearly the mechanisms governing these sys-tems’ treatment effectiveness and performance. Parties intending to construct passive treatment systems may refer to other sources that include more detailed design and construction guidance, including those listed as “Design Guidelines” in the references below. Articles by Skousen and Ziemkiewicz (2005), and Skousen (1996), contain photographs that illustrate many of these concepts.