Ask the Expert, Hazardous and Solid Waste

Where Can I Find a Listing of Thresholds or Limits of Metals/Chemicals Signifying Our Separated Solids as Hazardous?

Q. We have a triple basin collection system on our city sewer line that allows solids and oils to separate out, leaving just the water to continue on to the city. We have the solids tested at a local lab, but I am having trouble finding a listing of thresholds or limits of metals/chemicals signifying it as hazardous. I have found a few lists of contaminants but am unsure what pertains strictly to this sludge type waste.

A. From your question, we infer that you have already determined that your waste is not a listed hazardous waste and that you want to determine whether your sludge exhibits the hazardous characteristic of toxicity. The toxicity contaminants and their thresholds are listed in 40 CFR 261.24 and include metals (e.g. lead), dioxins (e.g. Vinyl Chloride), pesticides (e.g. Silvex), and volatile organic compounds (VOCs) (e.g. Benzene). If you want to test your waste for characteristics of ignitability, corrosivity, or reactivity, you should review the federal regulations at, respectively, 40 CFR 261.21, CFR 261.22, and CFR 261.23. These regulations specify the properties that must be present for the waste to qualify as one of these characteristic wastes.