Which analyses must sludge go through before being applied as Class B sludge?

• A. Nutrients (N&P); Metals; Pathogen densities (Fecal coli); Vector attraction reduction
• B. Temperature, pH, salinity, dissolved oxygen
• C. Bacterial counts, heavy metals only
• D. Radioactivity, pesticide residues, dioxins, PCBs

Answer: (A)

When you apply Class B biosolids, you must verify safety and compliance by testing for a set of key contaminants and risk factors. Specifically, you check nutrients to guide proper land-application rates, metals to ensure heavy metal limits aren’t exceeded, pathogen densities to confirm reduced pathogen levels, and vector attraction reduction to minimize attractiveness to pests and pests’ habitats. This combination ensures the sludge can be applied with controlled risk to human health and the environment, given that Class B biosolids are treated to reduce—but not eliminate—pathogens.

The other options don’t fit because they focus on process conditions or contaminants not part of the standard required set for preparing Class B biosolids for land application. Temperature, pH, salinity, and dissolved oxygen are process controls rather than the required analysis suite. Limiting the tests to bacterial counts and heavy metals omits nutrients and vector-attraction considerations. Focusing on radioactivity, pesticides, dioxins, and PCBs is outside the typical, mandated set for determining Class B suitability.