1 / 25

Managing Mercury Mania

Managing Mercury Mania. Jerald O. Thaler, P.E. Fishbeck, Thompson, Carr & Huber, Inc. Michigan Water Environment Association Annual IPP Seminar September 25, 2008. “Mercury 101”. The Wake-up Call.

clay
Download Presentation

Managing Mercury Mania

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Managing Mercury Mania Jerald O. Thaler, P.E. Fishbeck, Thompson, Carr & Huber, Inc. Michigan Water Environment Association Annual IPP Seminar September 25, 2008

  2. “Mercury 101”

  3. The Wake-up Call • In the 1950s and 1960s, Japan experienced an epidemic of psychotic disease and deformed/brain-damaged births • Traced to mercury poisoning from eating fish in Minamata Bay • Tons of mercury chloride was discharged by Chisso Corporation between 1931 and 1968 • Aquatic organisms convert inorganic mercury to highly toxic methylmercury • Methylmercury bioaccumulates up the food chain (~106x for trophic level 5) Bioaccumulation

  4. Regulatory Focus • Michigan has strict, long-standing controlson mercury in wastewater discharges • Only recently has focus increased on air emissions, where the impact is greater Tributaries (20%) Atmospheric Deposition (80%) Mercury Sources to Lake Michigan (adapted from Frequently Asked Questions About Atmospheric Deposition, USEPA, September 2001)

  5. Discharge Standards • Rule 57 provides protection against toxicity • Wildlife protection controls at 0.0013 μg/L, or 1.3 nanograms per liter (ng/L) • No mixing zone credit for BioaccumulativeChemicals of Concern

  6. Effluent Monitoring • Method 1631 • Grab sample • “Clean Hands/Dirty Hands” • Quantification acceptable for compliance testing • $90 each for 3 samples (duplicates plus field blank) • Method 245.1 • Composite sample • Normal handling • Quantification inconclusive for compliance testing • $40-$50 each (from Sample Collection for Ultra-Trace Concentrations of Mercury, Florida Department of Environmental Protection, ftp://ftp.dep.state.fl.us/pub/labs/assessment/ppt/utmsamp.ppt)

  7. NPDES Permit • Limits generally set at Level Currently Achievable (LCA) under multiple discharger variance • Initially 30 ng/L • Recently lowered to 10 ng/L • Soon to change to user-specific LCA • Applied as 12-month moving average • Effluent monitoring using Method 1631 • Mercury Minimization Program required

  8. Mercury Minimization Program • Goal to achieve effluent of 1.3 ng/L • Formal plan approvable by MDEQ • Annual status report • Required elements • Monitoring of influent, effluent, and biosolids • Source identification • Source reduction • Recommended elements • Public education

  9. Minimization Tips and Techniques

  10. Avoid the Regulatory Trap • Mercury in permit if potential effluent quality (PEQ) exceeds 1.3 ng/L • Per Rule 1211, PEQ is statistical tool to relate quality/quantity of monitoring data where factor set by number of samples (N): • PEQ = CMAX * Factor

  11. Avoid the Regulatory Trap • Permit application generally requires minimum of four effluent samples • Sometimes more samples may be better • If 4 samples with CMAX of 0.7 ng/L, PEQ>1.3 ng/L and permit will include mercury PEQ = 0.7*2.6= 1.8 ng/L • If 10 samples with CMAX of 0.7 ng/L, PEQ<1.3 ng/L and permit may not include mercury PEQ = 0.7*1.7= 1.2 ng/L

  12. Flexible Sewer Use Ordinance • Traditional command-and-control approach: “No discharge of detectable mercury.” • May not be feasible for some commercial users • Technical limitations • Economic factors • Strict enforcement may be counterproductive to local economy

  13. Flexible Sewer Use Ordinance • Alternative case-by-case approach: “No discharge of detectable mercury, except as specifically approved.” • Conditions of approval • Periodic self-monitoring • Minimization program (procedures, training, source identification/reduction, treatment, etc.) • All reasonable and cost-effective actions • Promotes flexibility and cooperation

  14. Identified Sources 0.05 MGD 700 ng/L Hg 0.107 lb/yr Hg Domestic/Background WWTP Influent WWTP Effluent 1.26 MGD 1.31 MGD 1.30 MGD 50 ng/L Hg 445 ng/L Hg 7.9 ng/L Hg 0.192 lb/yr Hg 1.773 lb/yr Hg 0.031 lb/yr Hg Unidentified Sources Average Removal By difference… 98% 1.474 lb/yr Hg Biosolids(6.5%) 396 T/yr 2.2 mg/kg Hg 1.742 lb/yr Hg Meaningful Monitoring • Evaluate monitoring data via mass balance to fully assess overall system • Example: Current Average

  15. Identified Sources 0.050 MGD 200 ng/L Hg 0.030 lb/yr Hg Domestic/Background WWTP Influent WWTP Effluent 1.25 MGD 1.31 MGD 1.3 MGD 50 ng/L Hg 63 ng/L Hg 1.3 ng/L Hg 0.190lb/yr Hg 0.250 lb/yr Hg 0.005 lb/yr Hg Unidentified Sources AverageRemoval By difference… 98% 0.073 lb/yr Hg Biosolids (6.5%) 396 T/yr 0.3 mg/kg Hg 0.255 lb/yr Hg Meaningful Monitoring • Apply mass balance results to prioritize minimization efforts -0.077 lb/yr -1.401 lb/yr Goal

  16. Productive Source Studies • Common sources • Domestic sewage (25-50 ng/L) • Dental offices • Other observed sources • Hospitals and medical clinics • State prisons • Car washes • Rainwater (~10 ng/L) and snowmelt • Use sampling of collection system to identify significant sources and maintain neutrality

  17. S-2 S-1 Source P-1 P-2 S-1' S-2' WWTP Productive Source Studies • Scattered sampling can be inconclusive due to high variability of mercury • Most efficient is moving upstream via “primary/secondary” scheme

  18. Deal With the Dentist • The most common controllable source of mercury • Mercury inherent to dentistry due to mercury-silver amalgams • Special challenge for smaller communities with multiple dentists

  19. Deal With the Dentist • Typical mercury generated per office 0.57 lb/yr Amalgam removal (97%) 0.02 lb/yr Amalgam placement (3%) 0.59 lb/yr Total • Removals for typical capture processes ~ 68% Chair-side traps ~ 40% Vacuum filters 81% Overall • Typical sewer discharge per office 0.59 * (1-.81) = 0.1 lb/year (ENVIRON International Corp., Evaluation of Mercury in Dental Facility Wastewater, Ver. 3, American Dental Association, Nov. 2002)

  20. Deal With the Dentist • Potential impact on treatment plant Assuming 2.5 million gal/day flow

  21. Deal With the Dentist • Amalgam Separator • >95% mercury removal for wet vacuum systems • Not overly complex or expensive • Can produce significant improvement at treatment plant • “…[Amalgam separator] systems work well, and we now feel comfortable including them in our best management practice recommendations." • Dr. Mark J. Feldman, President • American Dental Association • October 11, 2007

  22. Deal With the Dentist • Potential impact on treatment plant Again assuming 2.5 million gal/day flow

  23. Deal With the Dentist • Proposed Legislation • SB-1310/HB-6307 mandate amalgam separators by December 31, 2013 • Michigan Board of Dentistry to promulgate associated best management practices • However, prevents local authorities from pursuing further source reduction where warranted “This… supersedes any local ordinance… that imposes… additional standards on dentists… including… a permit that limits the discharge of mercury… greater than that capable of being achieved by full compliance with this section.”

  24. Perspective • Justifiable concern over mercury in waterways • Air emissions need same, or greater, scrutiny aswastewater discharges • Tips and techniques from experience • Avoid the regulatory trap • Flexible sewer use ordinance • Meaningful monitoring • Productive source studies • Deal with the dentist • Resist legislation that, while well-intended, pre-empts local authority/control

  25. For additional information: • Questions and Discussion Jerald O. Thaler, P.E. Fishbeck, Thompson, Carr & Huber, Inc. 39255 Country Club Drive, Suite B-25 Farmington Hills, MI 48331 jothaler@ftch.com 248-324-2090

More Related