American Peat Technologies

American Peat Technology (APT) Logo

Global has been providing engineering and water treatment expertise to APT on a variety of field and pilot studies for over two years. APT makes a peat sorption media (APTsorb™) that targets dissolved trace metals. The media is a hardened granule made from reed sedge peat that not only retains the metal removal capacity of natural peat but also has engineering properties that make it suitable for a variety of treatment applications.

Review some of our past results (below) or, to request more information on how APTsorb™ might solve your water quality problem, contact us. For additional information on APTsorb™ or  American Peat Technology, visit their  website.


Soudan Mine: Suspended and Dissolved Copper Removal

Presented at the 2014 American Society of Mining and Reclamation Conference, June 2014, Oklahoma City, Oklahoma

Solving mine drainage problems at the Soudan Mine; The Final? Answer

 Paul Eger, Global Minerals Engineering LLC, Hibbing, MN
Peggy Jones, Doug Green, Bob Forder, American Peat Technology, Aitkin, MN


The Soudan Mine, in northern MN, was a producing iron ore mine from 1882 to the end of mining in 1962. In 1963, the mine was donated to the State of Minnesota and became a state park in 1965. Since that time it has become important as a scientific research center and popular tourist destination. Water discharging from the mine contains elevated copper and cobalt and treatment is required. Since 2009, the water has been treated with a commercial ion exchange resin based system that includes flow equalization tanks, bag and cartridge filters, another flow equalization tank (break tank), a carbon tank and several ion exchange tanks. Although effective, the system’s high cost, inefficient removal of suspended material and substantial maintenance have been ongoing and troublesome issues. 

In November 2012, a pilot test was initiated using a peat based sorption media (APTsorb™ ). This media is produced from raw reed sedge peat through a patented carbonization process which produces a  hardened granular ion exchange material. The granules are uniform, have a high hydraulic conductivity and maintain the high metal affinity of natural peat

Mine water was pumped through the media without any pretreatment. Copper input typically ranges from 30 – 60 ug/l but concentrations increased to a maximum value of around 300 ug/l in the summer of 2013. Since startup, over 16 million gallons (> 30,000 bed volumes) have been treated with an average removal of around 75% for suspended copper and 60% for dissolved copper. Backwash is required at about 4000 bed volumes, but with a combination of air sparging and high flow backwash, the suspended material appears to be effectively removed from the bed.

The APTsorb™ media produced equivalent copper removal to the existing treatment system components of the bag and cartridge filters, the break tank, the carbon tank and the first commercial ion exchange tank. By reducing the size and complexity of the system, the capital and operation and maintenance costs are substantially reduced. Based on the existing data, using a single APTsorb™ tank will reduce annual operating costs by about a factor of 6; from around $130,000 to $21,000.

To see and hear the presentation on the Soudan Project go to:

Lead, Zinc and Cadmium Treatment

To be presented at the 2015 National Meeting of the Society of Mining Engineering, February 2015, Denver, Colorado

Getting the Lead out (and other Trace Metals) - Solving Mine Water Problems with Peat-based Sorption Media

 Paul Eger, Global Minerals Engineering LLC, Hibbing, MN
Peggy Jones, Doug Green, American Peat Technology, Aitkin, MN

 Pilot tests were run at two mines using peat-based sorption media to remove Pb, Zn and Cd. The first pilot was designed to model active (pressurized tank) and passive (biocell) approaches; the second contained only a pressurized tank.

At the first site, pH was greater than 7 and contained 1500 ug/l Pb, 100 ug/l Zn and 1.5 ug/l Cd. Both pilots removed over 99% of the lead and reduced all metals to below permit values. The biocell operated for about 9 months and met the permit limit of 11ug/l for 15000bv (bed volumes). When the pilot ended over 25,000 bv had been treated and Pb removal was still over 80%.

At the second site pH was also above 7 but zinc was the major parameter of concern. Input concentrations were 465 ug/l Zn, 135 ug/l Pb and 1.9 ug/l Cd. The peat media effectively removed Zn but after 4500 bed volumes the concentration exceeded the permit limit of 160 ug/l. An additional tank of media was installed and successfully reduced all metals to below permit limits; extending the lifetime of the initial tank to over 12,000 bv.

Treatment costs ranged from 43 to 90 cents per 1000 gallons; capital costs were less than 50% of a standard chemical treatment plant.

env-apt-image2 thumbPilot test, base metal mine
env-apt-image1 thumbConceptual design, full scale treatment module

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