Did you know that some waste treatment plants burn your poop or ship it to landfills, which aren’t the most economically or environmentally friendly solutions? But some human waste ends up on forests floors and farm fields after its been treated, these are called bio-solids- human-feces-based fertilizer. Here is the catch, humans have been re-purposing their feces for thousands of years and although bio-solids are cleaned and sterilized poop, nonetheless there’s a perception that it is “Bad” despite that it allows the land to keep vital nutrients, eliminates our waste in a products cycle and can be a safe effective fertilizer for crops. That is different than what is called “Night Soil” a famous example of raw human waste application of China, where human excrement was used for centuries in an attempt to close the nutrient cycle in their fields. However, because the “night soil” was untreated, pathogens could easily be transferred to both humans and food so eating raw vegetation was seriously frowned upon- as it should be.
However, the same cannot be said for bio-solids used in the United States because it is not night soil. Bio-solids are regulated by the EPA and federal codes, treatment plants are required to treat the waste at least once before it can be applied to any land. After you flush your waste is carried along with urine, rainwater and household water to a local sewage treatment plant. From there, bacteria digest the sludge which reducing the number of pathogens in the bio-solid. While the first treatment can be used with various restrictions, it requires a second treatment – often using high temperatures which turns the bio-solids into Class A bio-solids, which have no detectable pathogens and can be used anywhere. However now we have to accept the reality that groups who have money and power have stepped up to protect their fiefdom, by feeding us the narrative that human waste is and always will be unsafe.
So even when soil experts stress that while you’re still going to find higher levels of metals in bio-solids however the levels are still so low, and the chemistry of interactions between bio-solids and soil is such that availability to plants is very low and there is very little evidence to supports that we would see problems in the food chain or in the environments. We ignore that pharmaceuticals, heavy metals or steroids, are in many animals which would certainly find their way into animal manure, often in larger concentrations than bio-solids
So why don’t we find a new take human waste and find a new use for it. Human waste used to be dumped at sea causing major problem and was banned in the 1990s. If what homes, businesses, industry, hospitals and mortuaries put down drains was not so hazardous, the idea of using human waste for compost and fertilizer would be much safer. It’s not the poop that’s the issues, but the other things we put down the drain. To use bio-solids safely, we’d need sweeping chemical reform on a national level to keep harmful chemicals off the market in the first place. Sewage is commonly used in playgrounds, parks, athletic fields, gardens and golf courses. Sewage waste in compost products could contain heavy metals, industrial chemicals, trace pharmaceuticals and hormone-disrupting chemicals and other toxic compounds. Certain crops grown in human sewage sludge have been shown to “take up” heavy metals and common fragrance ingredients in everything from shampoo and soaps to lotions and makeup. There have even been cases where municipalities mix green waste with sewage sludge and give it away free.