To address naturally occurring mercury in the geological formation from which Aquifer Storage and Recovery (ASR) Well 4 draws and injects water, the design of a temporary mercury treatment system was necessary to maintain the well’s operation.  The 1,400 gpm treatment system consists of 12 pressure vessels filled with media, operating as six lead/lag trains.  The media is granular titanium oxide with a high affinity to adsorb heavy metals.  The media is non hazardous and the mercury will remain adsorbed for the life span of the media.  Also included in the design were pre-filters and interconnecting piping for connection to the well and to the distribution system. Valentine also coordinated review and approval of the mercury treatment system from the Department of Drinking Water.