The use of sulfur and sulfide in packed bed reactors for autotrophic denitrification

An experimental study was conducted on autotrophic denitrification using sulfide and elemental sulfur as electron donors in packed bed reactors. It was found that both of these sulfur compounds can be employed to obtain satisfactory denitrification in packed bed columns. In columns packed with elemental sulfur media, denitrification efficiency was found to be critically dependent on hydraulic retention time and sulfur particle size. An alkalinity consumption rate was determined to be 3.74 mg alk. (as CaCO₃) per mg NO₃-N reduced. This alkalinity consumption can be mitigated by adding crushed limestone to the packed bed reactor media.