Acidic Rock Drainage Treatment: A Review

Acidic rock drainage (ARD) is naturally produced through a series of chemical and biochemical reactions at abandoned mine sites. ARD containing acidity and a broad range of heavy metals is classified as hazardous, and must be properly treated. Many technical advances have been developed in recent years towards prediction, control, prevention, and treatment of ARD. This paper focused on the ARD treatment reviews on more than 85 patents filed mainly since year 2000. The patents surveyed are classified into four main types of ARD treatment: chemical precipitation process, adsorption method, biological system, passive treatment and others. The advanced technologies are discussed and evaluated. The key inventors and attractive applications are addressed. An assessment is made about current and future development of ARD treatment technologies.