Passive treatment system
Open-knowledge reference entry
A passive treatment system is a method for removing metals from acid mine drainage. There are several types of passive treatment systems, each of which may be used on their own or in combination to treat effluents. The type of system selected is dependent upon the chemistry of the acid mine drainage and the flow of the discharge, as well as relevant regulations. Passive treatment systems do not require power and are less expensive than active treatment systems. They also require less maintenance, which is an advantage in remote locations.
Types of passive treatment systems
There are many types of water treatment systems available for removing metals from acid mine drainage. Passive treatment systems are a relatively recent technology that involves using sulfate-reducing bacteria or limestone or both to neutralize acidity and precipitate metals. These systems are sometimes called “wetlands” or “bioreactors.” Passive treatment systems differ from active systems (water treatment plants), which commonly use power; use more hazardous chemicals such as hydrated lime, caustic soda, or ammonia; and, are more expensive. Passive treatment systems are preferred for sites managed by the Bureau of Land Management (BLM).
Passive treatment systems provide a controlled environment in which natural chemical and biological reactions that help in the treatment of
acid mine drainage can occur.
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