Why did we stop using human waste as fertilizers after the discovery of petroleum?
Well, I’m assuming we stopped using it after the discovery of petroleum, anyway. I’m not sure when we actually did stop using waste.
Well, I’m assuming we stopped using it after the discovery of petroleum, anyway. I’m not sure when we actually did stop using waste.
June 4th, 2010 at 9:26 am
As previously discussed, treated human waste, aka biosolids, is still used as a fertilizer. However, the use of manure, as a percent of total fertilizer used, decreased after the advent of petroleum, especially natural gas.
Part of this is due to the increase in total amount of fertilizer applied (which was a result in increased yield and increase in total number of acres planted), but a major function is simply cost. Biosolids have a much lower nutrient concentration than the synthetic (a majorly incorrect term) fertilizers used today. Consequently, the cost of shipping makes biosolid use economically attractive only if the farmer is located very far from the biosolid production source.
Additionally, biosolids are an unbalanced nutrient source. If one uses biosolids and desires to attain a competitive yield goal, eventually one or more nutrients in the soil will become excessively high and possibly a pollution issue. Currently phosphorus is typically excessive in those sites that have received biosolids continuously. This scenario is not as common with the use of synthetic fertilizers, as a balanced nutrient program is much easier to attain.
Finally, biosolids are a highly variable nutrient source. The composition is dependent on what is consumed by the individual producing the biosolids. What is in the biosolid, when it becomes plant available and how it becomes plant available, is often unknown when it is applied to the soil. This information is currently available for most, if not all, synthetic fertilizers.
Hope this helps.
June 4th, 2010 at 9:26 am
Actually treated human waste is still legal and used. A prime example of this is Milorganite, which is available at any garden store, as well as likely at Home Depot, Walmart, etc. This is actually composted sewage from the city of Milwaukee.
Raw human waste is not used as fertilizer anymore due to concerns over disease that may be carried in the waste and possibly onto the food, or more likely the people handling it. Being how most fertilizer is applied before or during planting, chances are slim of it affecting the food. However for some crops there are supplemental fertilizations that are given as it’s growing, which could cause a concern. Not to mention the thought of using raw human waste. is rather unappealing to most consumers!
Petroleum itself is not used in any fertilizers that I know of, although natural gas contributes to some common nitrogen sources. Most commercial fertilizers are mineral in nature that has been ground and refined. Also people have known of petroleum for hundreds or more likely thousands of years, it’s just been over the past century or so that we’ve found common practical uses for it.
I can’t really put a year to this, although someone else might be able to, but we stopped using raw human waste as fertilizer shortly after we discovered the disease risks associated with it. A more fair "landmark" to use rather than petroleum would be the discovery of pathogens.
June 4th, 2010 at 9:26 am
Actually, we stopped using it when we realized it spread human diseases. The intestinal problems that plague travelers to Mexico came from the Japanese farmers in western Mexico that used human waste as fertilizer.
June 4th, 2010 at 9:26 am
doesn’t store well, disease ridden, bad reputation, variable nutrition value, and harder to apply. More regulations to go with human waste application and storage than dry and gaseous N.
June 4th, 2010 at 8:33 pm
Biosolids is not just human waste; it is a complex and unpredictable mixture of thousands of man-made chemicals, pathogens, and industrial waste. Every industry, business, and institution is permitted, every month, to discharge 33 pounds of hazardous waste into sewage treatment plants. Here these pollutants, with the others, many of which are highly toxic and persistent and can be picked up by plants, are REMOVED from the waste water, but CONCENTRATE in the resulting sludge. The Federal Clean Water Act defines sewage sludge/biosolids as a pollutant. In fact, sludge is probably the most pollutant-rich material created by modern society. It does not belong on the land where we grow our food. For accurate information about using this contaminated waste as “fertilizer” visit
http://www.sludgefacts.org