The Washington DC water treatment plant appears to use sedimentation tanks for both treating water before consumption and for treating sewage that is then discharged.

My question: What happens to the sedimentation after it is collects? None of the articles that I have read discuss this.

It seems to me that the sediment in the water source won't necessarily be toxic, but I suspect that the sediment in the sewage contains a brew of toxic metals and organics. So does that need to be treated as toxic waste? Is the source sediment used for fertilizer, or is it just sent to a landfill? Is there an issue with dust?


1 Answer 1


I was part of a team of contractors to remove and spread the dried sediment from a water treatment facility - the sediment was a red cake/ powder and was spread on the fields as fertiliser.

  • $\begingroup$ Milwaukee WI sells it as Milorganite fertilizer . I filled a pick-up truck with it at a Cook Co ( Chicago IL) treatment plant. It was free garden fertilizer, but it took some paint off the truck bed. Interestingly , tomato seeds made it through the treatment ( decades ago). $\endgroup$ Feb 10, 2019 at 21:31

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.