The majority of sewage sludge is hauled away in trucks and disposed of on American farms. Some is given away or sold as “compost.” Some is dried and made into pellets, bagged, and sold as fertilizer. And sometimes sludge is “blended” into bagged fertilizers. There is no labeling requirement. Sometimes the product is called “biosolids,” sometimes not.
If sewage sludge -- whether “treated” or not -- is used as a fertilizer on crops, the food from these crops cannot receive USDA organic certification. But there is no federal rule that forbids non-organic fertilizers from using the term “organic.” The grower must know what he/she/they is putting on the land. Gardeners, too, have to do some investigative work if they buy compost or fertilizer. Look at the ingredients. If it says biosolids, don't buy it. If it says compost (as an ingredient), could be great (real compost is nourishing to soil and plants) but could be sludge ("compost" made from sewage sludge is toxic to soil and people). Coast of Maine, for example, uses compost in its lobster compost bags, but does not use sludge in any of its products, so its great stuff!
The Sierra Club has a May 2021 report on "forever chemicals' in bagged fertilizers made from sludge. It's loaded with PFAS, a dangerous family of toxicants.
Some Branded Products Containing Sewage Sludge
(Not a complete list)