BIOSOLIDS. It’s just a decent way of saying human waste, which is just a decent way of saying something not quite as nice. Ever heard the saying, “One man’s garbage is another man’s gold?” How about, “One man’s waste is another farmer’s fertilizer?” In some places in the world this saying is true. People’s waste is processed and turned into biosolids, which is then used as an agricultural fertilizer, believe it or not. You know that carrot you ate the other day? The one that tasted pretty good? Well, just think, that carrot could have been fermenting in your processed poop.
Processed poop is probably too harsh a term for this situation. The human waste travels to a sewage treatment plant where all hazardous contaminants are removed. The domestic sewage is then sent on to a waste water treatment plant where it undergoes numerous processes which clean it and remove the solids. These solids that are removed from the domestic waste are the actual fertilizer. Once separated, the solids can be treated with lime, which raises the pH and removes any odours. Now, we have our biosolids, which can be separated into two classes, Class A and Class B. Class A biosolids are higher quality and contain less pathogens, while Class B biosolids contain some contaminants as well as pathogens. The use of biosolids has been debated over constantly. Here, we will explore the pros and cons of using biosolids as a sustainable agricultural fertilizer.
PROS:
- Biosolids are a renewable resource. There will never be an end to our supply of domestic sewage, therefore we will not have to worry about overusing our reservoir.
- The use of biosolids as agricultural fertilizers will reduce the need for chemical fertilizers. This can save farmers money and increase the overall health of the plants being fertilized because chemical fertilizers can have negative results on the plants’ and the environment’s health.
- When we use biosolids we are also recycling. Everyone knows that recycling is good. If we didn’t recycle our waste then it would just fill up a landfill instead, or get dumped in a lake, so if using biosolids means that we’re recycling (even if its our own waste) it’s a good thing, right?
- The use of biosolids as agricultural fertilizers is cheaper than filling up landfills and buying chemical fertilizer since they are not synthesized.
- Crop production can be improved with the application of biosolids as agricultural fertilizer. Biosolids contain essential nutrients that greatly enhance a plant’s growth, such as nitrogen, phosphorus, and potassium. These nutrients also improve the quality of the soil, and can allow them to hold more water.
- Sites that were used for mining can sustain vegetation with the help of biosolids. The nutrients in the biosolids reduce the levels of toxic substances found in these mining sites and create a soil layer.
- Both the EPA (Environmental Protection Agency) and the National Academy of Sciences, after considering current practices, health concerns, and regulator standards, have deemed the use of biosolids as agricultural fertilizers safe. The National Academy of Sciences stated that, “The use of these materials in the production of crops for human consumption when practiced in accordance with existing federal guidelines and regulations, presents negligible risk to the consumer, to crop production and to the environment.”
CONS:
- Many countries have been hesitant to implement the use of biosolids as agricultural fertilizers because biosolids can contain an excess of metals. Though human waste is comparable to animal waste, human waste has higher concentrations of zinc, copper, lead, and molybdenum, all of which are metal. By using biosolids as an agricultural fertilizer there is the danger of metal accumulation in the land, which can lead to health problems of the plants and animals.
- Since biosolids contain many toxins such as dioxins and PCBs (polychlorinated biphenyls), if there was any contact between the biosolids and water, the water could be contaminated.
- There is also a chance that the air and food can be contaminated by the bacteria as well, leading to hazards for public health.
- Biosolids can also contain pathogens. A pathogen is any organism or substance that is capable of causing disease, such as a bacteria or virus.
- Some biosolids can still have a strong odour even after treatment. The smell can range from a slight ammonia smell to the distinctive smell of human waste.
- Though biosolids themselves are not costly, removing the toxins and the contaminants from human waste can be.
Looking back at the pros and cons of using biosolids as agricultural fertilizers, is it a realistic alternative to our current agricultural practices? The logic points to a yes but I think most of us will say no. The potential stakeholders in this issue are farmers, the government, and the companies who are producing biosolids.
Western view has influenced us to view human waste as an unsanitary and disgusting nuisance. We think that there can be no use for something as revolting as our own waste. Even when a viable option is at hand we tend to let it slide because our waste is just that… waste. Of course it looks gross and smells gross but so does animal waste. If we can use animal manure as fertilizer why can’t we use our own? If we can just get over the idea that our waste is unsanitary and disgusting then we can start to use it to benefit our world. I think the use biosolids as agricultural fertilizers is certainly a good alternative, and as long as I don’t think about what my carrot was fermenting in before I ate it then I’ll be fine.
Sources:
http://www.epa.gov/owm/mtb/biosolids/genqa.htm
http://www.biosolids.com/benefits.html
http://www.sencer.net/Outreach/pdfs/DCSymposium08/Posters/LUbiosolids.pdf
http://alfalfa.ucdavis.edu/+symposium/proceedings/2000/00-107.pdf
http://ehpnet1.niehs.nih.gov/qa/105-1focus/focusbeauty.html
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