Prevention of Acid Drainage from Stored Coal

A method has been identified for controlling acid production and subsequent dissolution of toxic pollutants in drainage from coal storage piles. Results of laboratory and field experiments indicate that it may be possible to prevent, rather than treat, acid drainage by periodically applying an environmentally safe detergent formulation to the coal. These experiments showed that a mild solution of sodium lauryl sulfate (SLS) effectively blocks the activity of the bacteria that promote acid formation and chemical leaching. Drainage from coal treated once with 50 mg/L of SLS remained neutral for 60 days, about three times longer than the untreated control sample. An extrapolation of results to an industrial‐scale application revealed that the cost of the SLS needed for a single application would likely be no more than $200 per acre of coal storage area ($500 per hectare) or, expressed per unit weight of coal, $4,000 per million metric tons.