The Petoskey WWTP Leachate Disposal Option Bay Harbor Regional Stakeholders Group April 28, 2010

Agenda Overview/Wrap-upDan Ralley City Manager Key Infrastructure Issues Dennis J. Benoit, P.E. Hubbell Roth & Clark, Inc. Key Operational & Regulatory Issues Jerald O. Thaler, P.E. Fishbeck, Thompson, Carr & Huber, Inc.

Potential Issues Commercial Users Residential Users Industrial Users WWTP Treated Effluent Biosolids ̶ Infrastructure ̶ Regulatory Leachate ̶ Infrastructure ̶ Operational ̶ Regulatory

Key Infrastructure Issues

The WWTP  1.5 million gallons/day current flow  Discharge to Little Traverse Bay CapdetWorks ®

System Improvements Necessary to safely and reliably accommodate leachate, and to optimize treatment for 20% increase in flow  Dedicated Pipeline (isolate leachate from wastewater)  Equalization Tank (store leachate and provide controlled blend with wastewater)  WWTP Modifications (ensure effective treatment and high quality effluent) While some WWTP modifications in City’s future capital improvement plan, must implement now for uninterruptable service

Dedicated Pipeline Forcemain separate from sanitary sewer 4-mile route with air reliefs, cleanouts, block valves City offering existing pipe through congested area Directional drilling will minimize surface disruption

Equalization Tank 1 million gal estimated total volume at Turcott Field Blend high TDS/low BOD leachate with wastewater  Flow balancing to stabilize leachate:wastewater ratio  Load balancing to stabilize food for microorganisms Buried tank will preserve park setting Previous site construction validates constructability

WWTP Modifications Upgrade headworks  Provide “clean” wastewater for blending Add third primary settling tank  Provide redundancy in case of unscheduled outages Improve aeration control  Promote health of potentially TDS-stressed microorganisms  Prevent foaming, bulking sludge, etc. Mitigate odors  Odors can form when leachate and wastewater mix Enhance biosolids handling  Solids can form when leachate and wastewater mix SCADA and laboratory  Support significantly increased control/monitoring requirements

Key Operational/Regulatory Issues

Effluent and Biosolids Quality Effluent to Little Traverse Bay  Tightly regulated by MDNRE  City has excellent compliance history Biosolids disposal via land application  Tightly regulated by MDNRE  City easily meets all applicable standards Neither can be compromised by accepting leachate

Industrial Pretreatment Program (IPP) Tightly regulated by MDNRE Required to protect WWTP effluent and biosolids  Sewer Use Ordinance  Nondomestic User Permits (e.g., Northern Michigan Hospital)  Surveillance by City staff Basis for leachate regulation  Flow of up to 300,000 gal/day  Self-monitoring requirements  Appropriate discharge limits

Mercury Bioaccumulative Chemical of Concern (BCC) in aquatic environment : City’s current NPDES permit limit is 10 ng/L (ppt)  “Level Currently Achievable” under MDNRE’s variance for existing dischargers  Long-term goal is water quality standard of 1.3 ng/L  Mercury Minimization Program required

Mercury Minimization City’s program extremely successful  Six consecutive years below water quality standard No change during/after leachate discharge in past: Included untreated leachate (except part of 2004) Leachate discharge ceased in July 2006

Mercury Treatment Monitoring data indicate excellent removals Expected effect of leachate on effluent:  0.5 ng/L → 0.7 ng/L  Well within water quality standard (1.3 ng/L) Expected effect of leachate on biosolids:  1.8 mg/kg → 2.1 mg/kg  Well within land application standard (17 mg/kg) Soluble>98% Insoluble~100% Total>99%

Whole Effluent Toxicity Acute toxicity ̶ Lethal to 50% of test organisms after hours ̶ Strictly prohibited by water quality standards Day-to-day, not average, requirement Standard test organisms Ceriodaphnia dubia Larval Fathead Minnow

Initial Evaluation by City Effluent mixed with:  Bay Harbor leachate (1:1:1 ratio of Seep 1, Seep 2, and Edge Drain)  East Park leachate  75/25 blend Acute toxicity when leachate content exceeded: December 2008-January 2009 LeachateCeriodaphniaFathead Minnow Bay Harbor13%20% East Park60%>100% 75/25 Blend(~8.5%)17% Great Lakes Environmental Center Traverse City, MI

Initial Evaluation by CMS Effluent mixed with  Approximately same blend of Bay Harbor and East Park leachates (75/25)  Bay Harbor leachate was 1:1:0.25 ratio of Seep 1, Seep 2, and Edge Drain Acute toxicity when leachate content exceeded December 2009 LeachateCeriodaphniaFathead Minnow 75/25 Blend23-29%-- AECom Environment Fort Collins Environmental Toxicology Laboratory Fort Collins, CO

Acute Toxicity Threshold Critical parameter relative to maximum allowable leachate flow (300,000 gal/day requested)  10% corresponds to about 150,000 gal/day  25% corresponds to about 375,000 gal/day Previous test results suggest significant influence by sources making up Bay Harbor leachate  City test based on 1:1:1 ratio of Seep 1, Seep2, and Edge Drain; CMS test based on 1:1:0.25 ratio  No data with Pine Court, which as reactivated in 2009  Unknown impact of day-to-day variations in Bay Harbor leachate “cocktail” (specific ion-ion interactions, not just TDS, known to influence toxicity)

Sensitivity Analysis City requested additional tests to evaluate effect of potential variation in Bay Harbor leachate “cocktail” Six tests, representing actual peak days for different leachate sources during plus average for 4 th Quarter of 2009: Requested tests have not been performed Date Seep 1 Seep 2 Edge Drain Pine Court East Park June 26, 2007:42%30%28%0% November 1, 2008:4%4%70%26%0% February 11, 2007:23%31%46%0% March 3, 2009:20%15%11%31%23% December 18, 2009:19%13%12%0%56% Average, Q4 2009:27% 11%22%

Wrap-up

SUMMARY Leachate can be accommodated if necessary system improvements are provided  Dedicated Line  Equalization Tank  WWTP Modifications Questions remain over acute toxicity threshold (leachate fraction in effluent ) and maximum allowable flow  Requested sensitivity tests must be performed Lower discharge mercury expected with WWTP disposal than direct discharge option

Questions and Discussion