Using a Metals Translator for Establishing NPDES Limits: A Case Study

Transcription

1 Using a Metals Translator for Establishing NPDES Limits: A Case Study Presented at 28 th Annual Environmental Permitting Summer School Marco Island, Florida Larry J. Danek, Ph.D. Environmental Consulting & Technology, Inc. Hazem Tamimi, P.E. City of Tallahassee July 2014

2 Hopkins Generating Station Beaver Creek Cooling Towers Tallahassee, Florida Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/2014 2

3 Problems Copper in the 2-MGD discharge exceeded the standard The 50-µg/L mixing allowance was revoked The NPDES renewal would include the lower limit Solutions Close the facility Dilute the discharge Reduce the cooling tower cycles Build a treatment facility Complete a copper translator study Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/2014 3

4 What is a metal translator? Original toxicity testing based on dissolved metals Standards based on total fraction Translator is the ratio of dissolved to total Process allows consideration for the ratio FDEP Guidance Document, December 2001 GUIDANCE FOR ESTABLISHING A METALS TRANSLATOR Florida Department of Environmental Protection Revision Date: December 17, 2001 Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/2014 4

5 Preliminary Testing Determine dissolve fraction Determine edge of mixing zone Evaluate the translator Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/2014 5

6 Preliminary Testing Results Equipment Blank Plant Effluent (D-001) Downstream (D1) Downstream (D2) Parameters TestAmerica Anatek TestAmerica Anatek TestAmerica Anatek TestAmerica Anatek December 26, 2008 Total copper (µg/l) < Total copper (µg/l) < Total Dissolved copper fraction copper (µg/l) (µg/l) (%) < < < Dissolved copper (µg/l) < Dissolved fraction (%) January 18, 2009 Total copper (µg/l) < Total copper (µg/l) < Total Dissolved copper fraction copper (µg/l) (µg/l) (%) <2.0 < < < Dissolved copper (µg/l) <2.0 <0.033 Dissolved fraction (%) Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/2014 6

7 Plan of Study Parameters Total and dissolved copper Hardness Total suspended solids ph Organic carbon Quality assurance Number of sampling events Worst-case operating conditions Sampling locations Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/2014 7

8 Worst-Case Conditions Receiving water considerations Critical flow Total suspended solids Hardness ph Organic carbon Seasonal variations Plant operating conditions Operating at full load Cooling tower cycles Units in operation Chemical additives Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/2014 8

9 Sampling Locations Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/2014 9

10 Point of Discharge (POD) Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/

11 D1 Looking Upstream Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/

12 D2 Looking Downstream Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/

13 D1A Looking Downstream Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/

14 30 Total Copper Downstream from Point of Discharge POD D1 D1A D2 25 Sampling Dates 4/15/10 Total Copper Criterion (based on hardness of 250 mg/l) [Current NPDES copper limit is 50 µg/l] 4/23/10 Total Copper (µg/l) /20/10 6/2/10 6/22/10 8/11/10 11/23/10 12/9/10 1/26/2011 3/21/ ,000 2,000 3,000 4,000 5,000 6,000 7,000 Geometric mean Downstream Distance from POD (ft) Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/

15 Dissolved Copper Downstream from Point of Discharge 30 POD D1 D1A D2 Dissolved Copper (µg/l) Dissolved Copper Criterion (based on hardness of 250 mg/l and a conversion factor of for dissolved copper) Sampling Dates 4/15/10 4/23/10 5/20/10 6/2/10 6/22/10 8/11/10 11/23/10 12/9/10 1/26/2011 3/21/ ,000 2,000 3,000 4,000 5,000 6,000 7,000 Geometric mean Downstream Distance from POD (ft) Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/

16 Dissolved Fraction of Copper Downstream from Point of Discharge 100 POD D1 D1A D2 90 Sampling Dates 80 4/15/10 Dissolved Fraction (%) /23/10 5/20/10 6/2/10 6/22/10 8/11/10 11/23/10 12/9/ /26/2011 3/21/ Geometric mean 0 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 Downstream Distance from POD (ft) Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/

17 Criteria Conversion Factors Metal for Dissolved Metals Freshwater Conversion Factors Saltwater Conversion Factors Cadmium* Chromium (III) Chromium (VI) Copper Lead* Nickel Silver Zinc *Conversion factors for cadmium and lead are hardness-dependent. Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/

18 Translator-Based Criteria Equation Translator-based criterion = dissolved copper criterion translator = exp 0.96 ( 0 { [ exp { ln lnh } }] ) Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/

19 Total and Dissolved Copper Criteria and Translator- Based Criteria for a Range of Hardness Values Hardness (mg/l as CaCO 3) Florida Class III Water Quality Standard Criteria (µg/l) Total Copper Dissolved Copper Translator-Based Total Copper Criteria (µg/l) Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/

20 Conclusions Preliminary evaluation is critical Dissolved fraction must be low Focused plan of study is key It works!! Y:\GDP-14\MKTG\PRSNT\ENVPRMSCH.PPTX 8/1/