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Item #4. 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
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Item #4 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, EvaluateFeasibility of CH3Hg 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
Method Development
Item #4 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?
TSS (mg/L)
Item #4 * * * * * Addition of Cl2 or H2O2
Item #4 Mass Balance?
Item #4 Interim Conclusions • Efficiencies: • HgTOT 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