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Nutrient Issues Update ACEc water resources committee

Nutrient Issues Update ACEc water resources committee. Steve Weiss. Frequency of reported TP. Basin Effluent TP Load Trends. Major Watershed Effluent Trends. Ambient Water Quality (CO J. Watkins MCPA Rochester). Historic WQ – Cannon River near Byllesby Reservoir 2001 flow and TP (ug/L).

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Nutrient Issues Update ACEc water resources committee

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  1. Nutrient Issues UpdateACEc water resources committee Steve Weiss

  2. Frequency of reported TP

  3. Basin Effluent TP Load Trends

  4. Major Watershed Effluent Trends

  5. Ambient Water Quality(CO 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

  6. Ambient Water Quality(from 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)

  7. 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 Focus primarily where sufficient Chl-a data exist ~ HUC 8/10 watershed outlets Public Hearings – Spring 2013 Rule Adoption – Winter 2014

  8. Nitrate Standard for surface waters • Likely 5 years off (my guesstimate) • Toxicity rather than nutrient standard • Draft chronic value • 2B warm & cool-waters <10 mg/L • 2A cold waters <5 mg/L • More toxicity testing scheduled (late 2012) • Limited NO3 effluent data • Difficult to characterize variability from facilities • Lots of ambient data

  9. 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

  10. VarianceMinn. R.  7053.0255 Subp. 4 / 7000.7000 / 7053.0195 • In the process of developing guidance • 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 periodically reevaluated

  11. Summary • 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.

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

  13. Extra Slides ↓

  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. Lake Eutrophication Standards Impaired Both cause (TP) and response (Chl-a/Secchi) must exceed Restoration / Effluent Limits Focus shifts primarily to meeting TP – significant progress towards attainment of response criteria

  18. 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

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