Hg Fate and Transport Within the San Jose/Santa Clara WPCP: Study Design and Interim Progress Report Item #4

Why? Baywide Hg TMDL Anything Special About POTW Hg? Do POTWs Methylate Hg? Where Does the Hg Go? NPDES Discharge Permit Provision Workplan (collection and analytical methods, schedule) Final Report (Hg F&T, Trends, Correlations, Evaluate Feasibility of CH 3 Hg Reduction Program) Item #4

Steps to Completion Method Development Workplan Literature Review Detailed SAP Phase 1 Sample Collection  Study Optimization  Phase 2 Sampling  Final Report Item #4

Method Development

The Treatment Process (simplified)

Treatment Process

The Plan Phase 1 Weekly  RS, PE, SS, NE, SE, FI, TFE, FE  Total, Filtered, Total Methyl (Selected Filtered Methyl)  TSS, Chloride, Sulfate, Sulfide  DO, Temp, pH, Conductivity Monthly  As above + Secondary/ Nitrification Quads  Sludge  Seasonal 24 hour sampling Monthly Item #4

The Plan Phase 2  Longer term, reduced frequency  Monthly RS, PE, NE, SE, FI, TFE, TFBW, FE  Weekly RS, FE  Special Focused Studies  More sludge?  Composites?  More 24 hour samples?  Other parameters? Item #4

TSS (mg/L)

Item #4

* * * * * Addition of C l2 or H 2 O 2 Item #4

Mass Balance? Item #4

Interim Conclusions Efficiencies: –Hg TOT 99% –Methyl Hg 97% –Dissolved Hg 50% Removal correlated with solids removal No evidence of methylation Flows sufficient to account for removal Temporal bias (daily fluctuation) Item #4

Next Steps Continue baseline Phase II sampling Independent review of Phase I results Discuss with Water Board Optimize sampling to answer questions Carry out optimized sampling Final Report 2007 Item #4