I was complaining to my sister about the sodium in Campbell's noodle soup and she said
that was nothing. She started talking about "Sewage Sludge" that farmers have been using for years... She said folks in or close to Richmond, Va. were protesting and trying to
keep the farmers from using the sludge in their fields. They failed and the sludge was poured and the odor was unbearable..

The Real Dirt on Sewage Sludge - Natural Life Magazine - green family living

The Real Dirt on Sewage Sludge
by Wendy Priesnitz
sewage sludge renamed as biosolids for fertilizer is dangerous
Hold your nose! Waste from households and industries treated at a sewage plant may be spread on a farmer's field near you. Unfortunately, it may contain heavy metals and other nasty surprises that could end up on your dinner plate.
The safe disposal of hazardous waste has been a challenge for both industry and governments for decades. Under increasing assault by environmental groups for dumping waste into landfills, oceans, rivers and lakes, or burning it in incinerators, corporations and governments seem to have agreed upon a new solution.
They rename the waste as fertilizer or dust suppressant and spread it on farmers’ fields and country roads. The code word for this practice is “beneficial use”. While it may be an environmentally sound example of recycling, in many cases it’s merely relocating pathogens rather than disposing of them.
Although many different industries are “recycling” their toxic waste in this manner, one of the most controversial substances is sewage sludge, which is widely used as a soil amendment by farmers in both the United States and Canada.
Sludge is the mud-like material that remains after treatment of the wastes that flow into local sewage treatment plants. If human wastes were the only thing entering the sewage treatment plants, then sewage sludge would be a relatively safe, nutrient-rich fertilizer that could be safely returned to the land. However, sewage treatment plants also inevitably receive industrial and household toxic wastes.

I added a link to read more.... Lots of info online about sludge. If interested, you can
do a search..