CMS Land Company


Treatability study and NPDES permitting for a leachate treatment system


Petoskey, Michigan

Project Highlights

  • Treatment pilot study
  • NPDES permit
  • Plume delineation
  • Mixing zone analysis
  • NPDES biological study
  • Mercury uptake study

Contracted by CMS Land Company (CMS), ECT designed, constructed, and operated a pilot ultrafiltration wastewater treatment plant for six months. ECT collected leachate wastewater from buried cement kiln dust. The leachate was high in mercury, total dissolved solids (TDS), and pH. ECT demonstrated to the Michigan Department of Environment, Great Lakes, and Energy (EGLE) (formerly MDEQ), the U.S. Environmental Protection Agency (EPA), the City of Petoskey, and the public, that the wastewater could be treated to meet National Pollutant Discharge Elimination System (NPDES) permit limits and/or the city’s pretreatment limits.

After the study, ECT assisted with negotiations between MDEQ and EPA to develop limits for an NPDES permit to discharge to Lake Michigan. The site clean-up and permit issuance was highly controversial and subject to public and regulatory oversight. In December 2010, MDEQ issued an NPDES discharge permit to CMS to discharge to Lake Michigan’s Little Traverse Bay.

In 2012, the TDS levels increased in both the collected leachate and the upgradient dilution wells. The increase prompted CMS to truck a portion of the collected leachate for deep well injection to avoid exceeding the NPDES permit limit for acute toxicity.

ECT conducted an acute mixing zone demonstration consisting of macroinvertebrate studies and effluent plume delineation to project the impact of full discharge of all treated leachate and negotiated with MDEQ permit staff to allow full discharge. MDEQ rejected the initial request, but after further negotiation and a modification of the outfall structure, MDEQ modified the permit. CMS was again able to discharge all effluent to the bay while meeting limitations. ECT continues to delineate the effluent plume periodically as a permit stipulation and continues to assist CMS Land with permit modifications, reissuance and compliance.

In 2013, ECT conducted a review of the groundwater sampling data from the site and submitted a successful groundwater/surface water interface (GSI) mixing zone demonstration to the MDEQ. ECT updated the study and renewed the demonstration in 2018.

From 2016 – 2018, ECT conducted a mercury uptake study in Lake Michigan adjacent to the site. The study measured mercury uptake by mussels and periphyton near the site, utilizing artificial substrate. ECT submitted the study to the MDEQ.