There is also the presence of toxic metals, hormones, prescription drugs. Plus who knows what kind of chemicals are present from toilet paper, makeup, shampoo, dish soaps, or whatever people decide to pour down the drain or flush down the toilet. One study found that plants can actually absorb a lot of these drugs from the biosolids: http://www.environmentalhealthnews.org/ehs/newscience/soy-plants-accumulate-drugs-antibacterials-from-biosolids/
If you read the EPA 503 rules about biosolids they use the language "pathogen reduction" and "minimizing the potential for regrowth of pathogenic bacteria." Thermophilic composting is
not sterilization. According to the EPA "
Composting is not a sterilization process and a properly composted product maintains an active population of beneficial microorganisms that compete against the pathogenic members. Under some conditions, explosive regrowth of pathogenic microorganisms is possible." If you just heat it to extremely high temperatures to kill all the pathogens, you also kill the beneficial bacteria too, which makes it more susceptible to pathogens colonizing the sterilized material, and takes away a lot of a major benefit of using compost in the first place (supressing diseases).
They test the sludge for some things, but don't test for a lot of other stuff (some heavy metals, carcinogens, endotoxins, etc). The workers at these plants have to wear full body suits and breathing masks. From a study on people living near farms where biosolids were applied:
"Results revealed that some reported health-related symptoms were statistically significantly elevated among the exposed residents, including excessive secretion of tears, abdominal bloating, jaundice, skin ulcer, dehydration, weight loss, and general weakness. The frequency of reported occurrence of bronchitis, upper respiratory infection, and giardiasis were also statistically significantly elevated. The findings suggest an increased risk for certain respiratory, gastrointestinal, and other diseases among residents living near farm fields on which the use of biosolids was permitted."
Sound like something you want to spread around your backyard? I understand they have to do something with the sludge, and it's illegal to dump it in the ocean. It's a noble thing to try to recycle it especially since phosphorous mines are supposedly going to run out eventually. The risk is probably pretty low, and there are toxic metals and pathogens found naturally in all soils, but it still isn't something I would use. There have also been major EPA budget cuts and deregulation the last 10 years. Class B biosolids have certain restrictions like they must be applied 20 months before planting anything and animals can't graze on land for 30 days after application. Especially now with the budget cuts and deregulation, who wants to bet some farmers are jumping the gun and not waiting the full period? Who knows, maybe some of these e. coli, salmonella, listeria (like the canteloupe one that killed 125 people) outbreaks are linked to biosolids?
I'll pass. I don't know for sure, but I would bet that those 40 lbs bags of "composted manure" and "topsoil" that sell for $1.XX probably contain sludge. They're pretty poor quality anyway.
Also, if it's OMRI certified it can't contain biosolids...
OMRI considers that sludge is synthetic for several reasons. Sludge composition varies widely, but inevitably
contains a number of constituents. In addition to organic matter from human waste, sludge also contains a broad
range of synthetic substances that have been intentionally or accidentally introduced into wastewater. These
include synthetic polymers, surfactants, metal salts, and industrial by-products. Commonly used household
products form another source of synthetic constituents found in sewage sludge. These include soaps, detergents,
cleansers, solvents, and drain cleaners. Many of these products are surfactants based on alkylphenol ethoxylates
(Talmage, 1994).
Crops also cannot be certified organic by the USDA NOP they were grown with biosolids:
Organic crops. The USDA organic seal verifies that irradiation, sewage sludge, synthetic fertilizers, prohibited pesticides, and genetically modified organisms were not used.