91-05: Relationship of Biofilm Formation on Stainless Steel in Untreated Once

A study was initiated in a 23,000 gpm once-through cooling water system for a 1200-megawatt nuclear plant that historically has experienced fouling with biofilms containing filamentous iron bacterial. The objective was to determine whether water quality variables correlate with biofilm formation. Stainless steel sampling stubs were exposed in this water system and biofilm developing on these stubs was quantified using cell counts, TOC, and total solids. Temperature, D.O., TOC, iron, manganese, and cell count were measured regularly on the water supplied to the sampling stubs. Correlations between biofilm formation and measured water quality parameters were determined.