Carbon is one of the simplest of the chemical elements and is the base material for many items used everyday. This presentation will review elemental carbon and discover activated carbon and how it is used in water and wastewater treatment - from pre-treating city water to removing harmful organics from wastewater effluent. In addition, we will review a case study describing the design development of an activated carbon system used to remove mercury from industrial wastewater. (BC-2011-2313 )