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Dennis Wasley and Steve Weiss

Eutrophication Standards and TP effluent Limits Update mwoa Laboratory Training Workshops june 27, 2013. Dennis Wasley and Steve Weiss. Overview. History of TP effluent limits in Minnesota Recent effluent quality and river data WQBELs. Phosphorus Limits: a brief history . 1971 ,

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Dennis Wasley and Steve Weiss

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  1. Eutrophication Standards and TP effluent Limits Updatemwoa Laboratory Training Workshopsjune 27, 2013 Dennis Wasley and Steve Weiss

  2. Overview • History of TP effluent limits in Minnesota • Recent effluent quality and river data • WQBELs

  3. 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

  4. 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

  5. Recent effluent data

  6. Frequency of reported TP

  7. Basin Effluent TP Load Trends

  8. Major Watershed Trends

  9. St. Croix at Prescott

  10. Minnesota at Fort Snelling

  11. Mississippi at Lock and Dam 3 0.4 0.3 0.2

  12. Current driver for TP limits: Lake eutrophication standards

  13. Lake Eutrophication Standards

  14. 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

  15. Water Quality Based Effluent Limits • Federal regulations • 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

  16. WQBELs • if TMDL complete WQBEL ~ WLA • If TMDL in draft form – will scavenge best available material • If no TMDL started, will run TMDL-like analysis

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

  18. Load Allocation

  19. Mass and Concentration Limits 0.98 mg/L

  20. Future driver for TP limits: River eutrophication standards

  21. River Eutrophication Standards Not here yet ….but in the near future

  22. 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)

  23. 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

  24. 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

  25. 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

  26. 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.

  27. Dennis Wasley Dennis.Wasley@state.mn.us (651) 757- 2809

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