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Nutrient Standards Update Conference on the Environment November 13, 2012

Nutrient Standards Update Conference on the Environment November 13, 2012. Steve Weiss. Phosphorus Limits: a brief history . 1971 , 1.0 mg/L limit if discharge to special designated waters. (e.g. Lk. Superior Basin) Later - Minn.R. 7065.

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Nutrient Standards Update Conference on the Environment November 13, 2012

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  1. Nutrient Standards UpdateConference on the EnvironmentNovember 13, 2012 Steve Weiss

  2. Phosphorus Limits: a brief history • 1971, • 1.0 mg/L limit if discharge to special designated waters. (e.g. Lk. Superior Basin) • Later - Minn.R. 7065 • March 2000, Phosphorus Strategy Introduced “de minimus” concept for new or expanding facilities. • 1973 • 1.0 mg/L limit if discharge is directly to or affects a lake. • Later - Minn.R. 7050.0211 • 1990’s – 2000’s • Research and development of numeric eutrophication standards

  3. Phosphorus Limits: a brief history • 2008 • P Strategy promulgated , existing P limit rules condensed. (Minn.R. 7053.0255) • March 2010 • P Decision Tree - Greater focus on federal regulations (WQBELs) • 2008 • Numeric Lake Eutrophication Standards Adopted • (Minn.R. 7050.0222) • 1st five year permit cycle following rule adoption

  4. Frequency of reported TP

  5. Basin Effluent TP Load Trends

  6. Major Watershed Trends

  7. Major Watershed Trends

  8. Ambient Water Quality(J. Watkins MCPA Rochester) Historic WQ – Cannon River near Byllesby Reservoir 2001 flow and TP (ug/L) low flow super high phosphorus !!! ~350 ug/L

  9. Ambient Water Quality(J. Watkins MCPA Rochester) Current WQ – Cannon River near Byllesby Reservoir Hints of improvement? Tough to tell, but maybe. Owatonna and Faribault WWTPs to 1.0 mg/L Jan 2012 recent low flow condition much lower TP (<100 ug/L)

  10. Lake Eutrophication Standards

  11. Lake Eutrophication Standards

  12. Lake Dischargers • 85% discharge upstream of a lake in MN • Of those 80% are upstream of a nutrient impaired lake • Phosphorus is “persistent” • Not volatile • Build up and wash out

  13. River Eutrophication Standards Not here yet ….but in the near future Assessment both cause (TP) and response (Chl-a/other) must exceed to be impaired Implement TP target – make significant progress towards Chl-a criteria Focus primarily where sufficient Chl-a data exist ~ HUC 8/10 watershed outlets

  14. Water Quality Based Effluent Limits • WQBELs - 40 CFR 122.44 (d)(1)(i) • Limit set to achieve state water quality criteria. • Required for dischargers with reasonable potential to cause or contribute to an excursion in water quality standards • In Minnesota, RP determined when: • Discharge upstream of P impaired water • No intervening nutrient trap between outfall and resource of concern • Discharge at concentration above ambient WQS

  15. WQBELs • Method dependent on best available data and tools • if TMDL complete WQBEL ~ WLA • If TMDL in draft form – will scavenge best available material • If no TMDL started, will run TMDL-like analysis • Estimate all major sources, determine limits based on reduction potential • Limits determined on case-by-case basis

  16. Resource Assessment • Estimate source loads • Enter into lake model • Estimates current lake condition • Reductions necessary to meet standards

  17. Load Allocation

  18. Mass and Concentration Limits 0.98 mg/L

  19. Out of State • Gulf of Mexico – Hypoxia • Lake Winnipeg – Manitoba • Increased eutrophication in past 15 yrs. • Red River • 16 % flow • 68% annual phosphorus load (Environment Canada, 2011) • 1909 Boundary Waters Treaty “waters flowing across the boundary shall not be polluted on either side to the injury of health or property on the other.”(Article IV)

  20. Nitrate Standard for surface waters • Likely 5 years off (my guesstimate) • Toxicity rather than nutrient standard • Draft value near 10 mg/L (+ 5) • Limited NO3 effluent data • Difficult to characterize variability from facilities • Lots of ambient data

  21. Schedules of Compliance Federal Law (40 CFR 122.2, 40 CFR 122.47) “As soon as possible” 2007 EPA Memo , James Hanlon • Based on time necessary to plan, build and secure funding for treatment option chosen by permittee • May extend beyond 5 year permit – must be justified “ASAP” • May not be based on time required to: • Complete TMDL • Explore UAA Not eligible for: • Facilities able to meet WQBEL • New discharges Most likely for existing dischargers w/ new limits that: • Require additional treatment • Outfall relocation

  22. VarianceMinn. R.  7053.0255 Subp. 4 / 7000.7000 / 7053.0195 • Written request from permittee • Should address all applicable components of Minn.R. 7000.7000 Subp.2. A-H • Fee associated with application • Fee does not guarantee acceptance • When appropriate? • Technology not available to meet standard • Very high per capita treatment cost • Economic hardship • Not permanent relaxation of limit • Must be reevaluated every three years

  23. Summary • TP limits developed on case-by-case basis • Numeric river eutrophication standards in future may require more restrictive limits for select facilities • If upgrading, consider designing for nitrate removal – may have surface water standard in future.

  24. Steve Weiss Steven.Weiss@state.mn.us (651) 757- 2814

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