General Recycling Industries is to pay $75,000 after it was caught pumping oily water into the sewer.
That sewer flows into Mill Creek in the middle of Edmonton, which in turns flows into the North Saskatchewan.
The waste water was tested and found to be harmful to fish, which violates the Fisheries Act.
Environment Canada couldn't immediately say what was in the waste water or how much of it entered the river.
The money is to go into the federal Environmental Damages Fund, which is used to pay for habitat restoration projects.