Described herein are methods, apparatuses, and systems for reducing the sulfur content of coal. Coal is loaded into an apparatus comprising a vertically rotatable drum within a housing. The rotatable drum comprises a perforated cylindrical outer wall, a solid cylindrical inner wall, and a perforated, cylindrical central wall positioned between the outer wall and the inner wall, wherein the coal is loaded into a coal wash annulus between the central wall and the outer wall. A microbial wash fluid flows into a wash fluid annulus between the inner wall and the central wall, wherein the microbial wash fluid contains sulfur digesting bacteria and nutrients for the bacteria. The drum is rotated to cause the microbial wash fluid to migrate from the wash fluid annulus through the coal in the coal wash annulus and collect in a splash wash annulus between the outer wall and the housing.
展开▼
