ODOR CONTROL EFFORTS ARE IMPROVED FOLLOWING DISCOVERY OF UNUSUALLY HIGH ORTHOPHOSPHATE LEVELS IN WASTEWATER COLLECTION SYSTEM

For several years, the City of Battle Ground ("City") and the Hazel Dell Sewer District have received hydrogen sulfide (H2S) related odor complaints along N.E. Salmon Creek Avenue in unincorporated Clark County, Washington. Previous attempts to prevent the stripping of gas phase H2S at a forcemain discharge vault on N.E. Salmon Creek Road have been largely unsuccessful. These attempts have included the separate addition of ferrous chloride and ferric chloride. Figure 1 presents a chart showing gas phase hydrogen sulfide data taken at the discharge vault with the addition of ferric chloride to the wastewater at the pump station wet well.