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The State of Washington enacted legislation (Senate Bill 5033) mandating certain testing requirements for biosolids utilized in agriculture.
The testing requirements addresses per- and polyfluoroalkyl substances (“PFAS”).
Domestic sewage that is transported and conveyed to a wastewater treatment plant is treated to separate liquids from solids. This produces a semi-solid, nutrient-rich product often referred to a sewage sludge. However, the terms “biosolids” and “sewage sludge” are often used interchangeably. Nevertheless, the United States Environmental Protection Agency uses the term “biosolids” to refer to sewage sludge that has been treated to meet the requirements int het federal agency’s regulation entitled:
Standards for the Use or Disposal of Sewage Sludge.
This is material intended to be applied to land as a soil conditioner or fertilizer. See 40 C.F.R. Part 503.
SB 5033 requires that by July 1, 2026, Washington State Department of Ecology (“Department”):
…publish guidance to clarify PFAS chemical sampling requirements, including frequency and methodology, for facilities generating biosolids.
As a result, facilities generating biosolids regulated under the relevant chapter are required to sample for PFAS chemicals in accordance with such guidance and have the material analyzed by an accredited laboratory for PFAS chemicals using the United States Environmental Protection Agency’s method 1633A as it existed in December 2024, no more than quarterly starting no later than January 1, 2027, and ending by June 30, 2028.
A copy of Senate Bill 5033 can be downloaded here.
