Hg Fate and Transport Within theHg Fate and Transport Within theSan Jose/Santa Clara WPCP:San Jose/Santa Clara WPCP:

Study Design and PreliminaryStudy Design and PreliminaryResultsResults

Drivers:

• Baywide Hg TMDL1. Anything Special About POTW Hg?2. Do POTWs Methylate Hg?3. Where Does the Hg Go?

• NPDES Discharge Permit Provisiona) Workplan (collection and analytical methods, schedule)b) Final Report (Hg F&T, Trends, Correlations, Evaluate Feasibility of

CH3Hg Reduction Program)

ProgressMethod Development

Workplan

Literature Review

Detailed SAP

Phase 1 Sample Collection

Study Optimization

Phase 2 Sampling

Final Report

The Treatment Process(simplified)

Treatment Process

The PlanPhase 1

Weekly RS, PE, SS, NE, SE, FI, TFE, FE

Total, Filtered, Total Methyl

TSS, Chloride, Sulfate, Sulfide, DO, Temp, pH, Cond.

Monthly As above + Secondary/Nitrification Quads

Sludge

Phase 2 Longer term, reduced frequency

Possible gas sampling

209

9989

8 9 82<1

0

50

100

150

200

250

300

350

RS PE SS N E SE FI TFE FE

TSS(mg/L)

Total Mercury(ng/L) n=16

193.7

89.8100.2

5.7 5.6 5.5 1.7 2.2

0

50

100

150

200

250

300

RS PE SS N E SE FI TFE FE

Total Methylmercury(ng/L)

1.3031.365

1.304

0.045 0.040 0.049 0.027 0.029

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

RS PE SS N E SE FI TFE FE

Secondary Process CH3HgTSS Normalized (n=3)

0.0000

0.0005

0.0010

0.0015

0.0020

0.0025

0.0030

NQ1 NQ2 NQ3 NQ4 SQ1 SQ2 SQ3 SQ4

Dissolved Mercury (ng/L) n=16

2.87

3.55 3.59

0.840.97

1.171.37

1.53

0.0

1.0

2.0

3.0

4.0

5.0

RS PE SS N E SE FI TFE FE

SLUDGE

Sludge Total Mercury(mg/kg dry) n=2

2.08

0.80

0.95

0.77

1.83

1.68

0.00

0.50

1.00

1.50

2.00

2.50

3.00

PS WAS WNS TAS DS SL

Next Steps

• Evaluate Phase 1 Data

• Possibility of gas phase sampling

• Optimize Sampling for Phase 2

• Carry Out Optimized Sampling(seasonal)

• Final Report 2007

• Learn to Surf