Mercury Issues: Two Perspectives

Transcription

1 Mercury Issues: Two Perspectives NC Pretreatment Consortium Mercury 101 Workshop December 17, Greensboro NC

2 MERCURY: A POTW View Martie Groome Laboratory & Industrial Waste Supervisor Water Resources Department City of Greensboro, North Carolina

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4 Greensboro, North Carolina 2 POTWs (~ 50% hydraulically loaded) 16 MGD Activated Sludge Tertiary Treatment 4 SIUs - (1) Tobacco Products (3) Electroplaters MGD Activated Sludge Tertiary Treatment 29 SIUs - (1) CWT (2) TEC (2) Pharmaceuticals (3) OCPSF (7) Metal Finishers (2) Electroplaters-413 (4) Textiles (1) Tobacco (1) Industrial Laundry (3) Electrical & Electronic Components (1) Capsule Mfg. (1) Chemical Packaging (1) Photographic Paper Sludge Incineration (since 1970) Fluidized Bed Incinerator All solids handling at the 40 MGD POTW

5 Greensboro and Mercury No Amalgam Separator Program Number of Dentists 4643 Dentists in North Carolina in in Guilford County NC Assume ~200 in Greensboro Configuration of Dental Offices Most dentists in service area of 16 MGD POTW Average Influent Hg 16 MGD POTW = ug/l Average Influent Hg 40 MGD POTW = ug/l

6 Mercury As A POTW Pollutant of Concern NPDES Permit or Water Quality Standard Stay in compliance/protect the Receiving Water Activated Sludge Inhibition Protect our Bugs at the POTW Biosolids/Sludge Criteria Land application limits/incinerator air quality limits Pretreatment MAHLs for Mercury Calculate how much mercury can be discharged to the POTW and still meet everything above!!!

7 Hg = Pollutant of Concern: NPDES Permit Limits NPDES Permit Limits (both POTWs) Daily Maximum Limit 12 ng/l = mg/l North Carolina Mercury WQS = mg/l IWCs = 97% and 96% so NPDES limit is the WQS! NPDES Permit requires weekly effluent Low Level Mercury Sampling (1669) and Analysis (1631) POTW influents also sampled/analyzed weekly Sampling and Analyses Currently Contracted out to Commercial Lab >$28,000 per year

8 Mercury Compliance History NPDES VIOLATIONS: with 12 ppt DM limits CY 16 MGD POTW 40 MGD POTW / 312 analyses 11 / 312 analyses % Compliance 99.7% 96.4%

9 Observations Violations Occurred When Total Suspended Solids > 10 mg/l TSS NPDES Permit Limit = 30 mg/l CBOD 5 NPDES Permit Limit = 4.0 mg/l POTW Recorded High Influent Flows following precipitation events Gulley Washers Legacy mercury (heavy so lays in bottom of pipes) Siphons TSS >10 mg/l

10 Hg = Pollutant of Concern: Activated Sludge Inhibition Method Aeration Grab Composite Quarterly Mercury Analyses - Review all NPDES Limits during the sampling to determine no impact Inhibition Literature Values from EPA Activated Sludge: 0.1 mg/l Nitrification: No value available Maximum Values From Greensboro POTWs 16 MGD POTW = <0.2 mg/l (used literature) 40 MGD POTW = <0.2 mg/l (used literature)

11 Hg = Pollutant of Concern: Biosolids/Sludge Greensboro Incinerates Sludge, but. We Still Analyze Sludge for all Land Application Metals - Goal is to Meet High Quality Sludge Concentrations Incorrect assumption that POTWs incinerate because they cannot meet land application criteria New MACT (Air Quality) Mercury Standards for Incinerators issued in 2011 Meeting the new very stringent limit...but close!

12 Greensboro Biosolids Mercury Concentrations mg/kg Year Average Maximum CFR Part Table 1 - Ceiling Concentration Hg Limit = 57 mg/kg Table 3 - High Quality Biosolids Hg Limit = 17 mg/kg

13 NACWA Biosolids Data MP&M Regulation Submittal 155 POTWs Submitted Hg Biosolids Data Represented 1,511,092 Dry Metric Tons Number of POTWs not meeting Hg Ceiling Limit of 57 mg/kg = 0/155 Number of POTWs not meeting Hg High Quality Sludge Limit of 17 mg/kg = 1/155 Avg Hg Biosolids Concentration = 2.98 mg/kg

14 CY 2007 CY 2012 Greensboro Mercury Averages 16 MGD POTW (North Buffalo) Influent Effluent % Removal ug/l ug/l 98.8% 40 MGD POTW (T. Z. Osborne) Influent Effluent % Removal ug/l ug/l 84.9%

15 Pretreatment MAHLs for Mercury (2012 HWA) Mercury Removal Rates (using 1631 data) 16 MGD POTW = 99% 40 MGD POTW = 85% EPA Literature Median Removal Rate = 60% Maximum Allowable Headworks Loadings 16 MGD POTW = pounds Based on NPDES permit limit Allowable HW Loading 40 MGD POTW = pounds Based on NPDES permit limit Allowable HW Loading

16 National Dialogue On EPA Dental Amalgam Regulation Proposal: Martie Groome National Association of Clean Water Agencies Vice Chair-Pretreatment Committee

17 Background Information Effluent Limitations Guidelines [ELG] a.k.a Federal Categorical Standards Direct Discharge Standards Used by State and EPA NPDES Permit writers Pretreatment Standards [PSES, PSNS] If it starts with a P the regs are for me! For Indirect Dischargers to POTWs Used by POTW SIU Permit writers (Pretreatment Coordinators)

18 Background Information 40 CFR Part 403: If you are subject to a Federal Categorical PT Standard =SIU Optional PT Streamlining Caveat: Non-Significant Categorical Industrial User (NSCIU) Never discharges >100 gpd categorical wastewater Must have shown consistent compliance with all applicable Categorical Pretreatment Standards** Never discharges untreated concentrated wastewater **Note: Therefore, SIU cannot start out as a NSCIU Decreased monitoring and inspection for NSCIU

19 What EPA Said Round 1 We are thinking about promulgating a new Categorical Standard for dentists The regulation would require all dentists to install amalgam separators to reduce mercury discharges to the POTWs and ultimately reduce mercury discharges to the surface waters What comments do you pretreatment folks have about this?

20 What We Said Round 1 Do you realize how many dentists there are in the United States? Have you looked at the potential impact on every Pretreatment Program in this country if we have that many new Significant Industrial Users to regulate? Virtually every PT program will have dentists! Are POTWs really a significant source of mercury in the environment?

21 EPA September 2010 Memo EPA intends to propose rule to reduce mercury waste from dental offices EPA expects to propose a rule in October 2011 and finalize it in October 2012 (still not issued!) Dental amalgams, or fillings containing mercury, account for 3.7 tons of mercury discharged from dental offices each year. Mercury in dental fillings is flushed into chair-side drains and enters the wastewater systems, making its way into the environment through discharges to rivers and lakes, incineration or land application of sewage sludge

22 EPA September 2010 Memo Mercury released through amalgam discharges can be easily managed/prevented. Amalgam separators can separate out 95% of the mercury normally discharged to the local POTWs. Approximately 50% of mercury entering local POTWs comes from dental amalgam waste Certain microorganisms can change elemental mercury into methylmercury, a highly toxic form that builds up in fish, shellfish and animals that eat fish.

23 PT Committee Concerns- What We Said Round 2 If traditional Categorical Standards are promulgated, over 100,000 new SIUs created Overwhelm POTWs with workload with PT staff Annual inspections required for SIUs Annual sampling required for SIUs Some programs would increase by order of magnitude Greensboro NC: 34 SIUs to ~234 SIUs NSCIU caveat is not a required PT Streamlining change-some states chose not to adopt it Also current EPA regs will not allow a discharger to become a NSCIU from day one

24 PT Committee Concerns- What We Said Round 2 Numerical Standard vs. Best Mgmt Practices Very difficult to accurately sample low/intermittent flows from a dental practice, esp. a small one Amalgam Separator Manufacturer Approvals Problematic for every POTW in country to do separator assessment and approvals Amalgam Separators Already in Use What if they cannot meet criteria in the reg? Do we punish them for being proactive?

25 NACWA Suggestions to EPA Create New Classification for Dentists Not SIU and Not NSCIU Adopt BMPs rather than Numerical Standard Include separator O&M in BMP Grandfather Existing In-Place Separators Even if they do not meet criteria in new regs Reasonable final compliance date for POTWs to bring all dentists into the program EPA should Approve Amalgam Separators POTWs do not want the liability

26 Amalgam Separator Criteria We do not know what EPA will eventually promulgate.but here are some options % Solids Removal Some POTWs have required 95% Some POTWs have required 98% ISO Tested/Certified Separators Best Management Practices for O&M of separators

27 Dentists: The Local Numbers North Carolina Number of Dentists: 4,643 [2009 data] Number of SIUs: 630 [2011 data] South Carolina Number of Dentists: 2,026 [2007 data] Number of SIUs: 435 Question all POTW PT folks ask: What about the dentists who are on septic tanks?

28 Number of Dentists in NC By County in Total Guilford 277 Johnston 37 Halifax 10 Jones 2 Harnett 18 Lee 22 Haywood 27 Lenoir 26 Henderson 49 Lincoln 25 Hertford 7 McDowell 15 Hoke 6 Macon 4 Hyde 0 Madison 5 Iredell 78 Martin 7 Jackson 17 Mecklenburg 618

29 The Bottom Line in Greensboro Mercury: Assume 50% Removal* 16 MGD POTW [~6.0 MGD] Influent Effluent Inf. lbs/yr = ug/l ug/l Eff. lbs/yr = MGD POTW [~22.0 MGD] Influent Effluent Inf. lbs/yr = ug/l ug/l Eff. lbs/yr = Total Influent Mercury per year = 6.82 pounds Total Effluent Mercury per year = pounds* 1 FTE = $50,000/0.223* pounds = $224,215/pound

30 Where Are We Now? EPA has draft regulations that have been distributed and reviewed internally Proposed as 40 CFR Part 441 We do not know exactly what regs say But some EPA staff have said: We heard you! Regs have not gone to Office of Management and Budget review yet Way behind schedule typical for EPA and some PT folks think they will never come out!

31 What Happens Next? Regulations to OMB for review and comment EPA addresses OMB Issues if any Draft Regulations out for public comment EPA receives public comments (and must address each one) Final Regulation promulgated Compliance Period Final Compliance Date

32 What Can A POTW Do Now? Develop list of dentists in your service area Contact state and/or local Dental Associations May or may not be aware of the upcoming regulation How would this many new SIUs impact YOUR PT program? Look at this so you can (1) comment on regulations (2) ask for more staff or (3) RETIRE! Baseline Mercury analyses: POTW Influent, POTW Effluent, Activated Sludge, Biosolids

33 But It s Just One More Regulation

34 But remember When you are in deep trouble, say nothing, and try to look like you know what you're doing!