Environmental Filtration Inc.
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A new system that removes pollutants from runoff...

Before it gets into your lakes and streams...

And it also removes pollutants from industrial wastewater.


Lyle Clemenson (President of EFI) first became involved in stormwater back in 1991. He was then, chair of a task force for the City of Brooklyn Park planning for stormwater runoff. Contaminant romoval was also discussed.

Initially, he assumed that when the plan was finished, it would be simply a matter of purchasing and installing filtration systems. Then buy filters needed and to remove the contaminants from stormwater runoff.

To his great surprise there was no such system.

Being an inventor/engineer, Lyle began thinking about how the contaminant removal could be accomplished. Having had a construction company for ten years and having constructed many catch basin and storm drain systems, Lyle believed that the obvious place to begin was in existing catch basins. He looked at many catch basin designs and determined that the filtration canister's size should be 20" in diameter and 36 inches long.

Next a medium must be found that would work in this size unit. There were a number of options and among those were: sawdust, cellulose, raw pear, activated carbon, etc. Activated carbon is widely used and raw peat also works to a degree. However, activated carbon comes in a granular form and will only allow a limited amount of water through. Raw peat does a reasonable job of filtering, but also passes water at very low rates.

After much research and study, Lyle learned that Bemidji State University had begun working with sulfinating peat to enhance the removal characteristics for heavy metals.

Starting in 1995, working with a consultant from the US Bureau of Mines, they began research on sulfonating peat. After months of testing and processing they developed and formulated a process for sulfonating peat, extruding it, drying it, and sintering it to make pellets that work for removing contaminants from stormwater runoff. He recieved a patent for the process in 2000.

The size of the pellets determines the flow rate and therefore, determines the quantity of water to flow through the catch basin.

Since mid 1997, Environmental Filtration Inc., has had a number of canisters in catch basins in Brooklyn Park, and other cities in Minnesota. The research, development, and validation continues.

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©2000 Envrionmental Filtration, Inc. 10650 County Road 81, Suite F, Maple Grove, MN 55369