Fertilizer is separated into two categories: organic and inorganic.
When I think of organic fertilizer, my mind ponders on the idea of cow manure and compost.
However in many countries, including Canada, the United States and several countries in Europe, biosolids from sewage treatment plants are treated and used as sustainable agricultural fertilizer. The question at hand is whether it can be a realistic alternative to our current agricultural practices.
First and foremost, what are biosolids?
Biosolids are nutrient-rich organic materials resulting from the treatment of domestic sewage in a treatment facility. When treated and processed, these residuals can be recycled and applied as fertilizer to improve and maintain productive soils and stimulate plant growth.
Before making any decision, it is best to consider the pros and cons of each choice.
Pros of Biosolids
When I first read about biosolids, another term for human waste, I was appalled by the thought of our sewage going into the food we eat! However, as I researched more about biosolids, I found out that biosolids are a result of treated wastewater, that makes the sewage safer for recreation and harvesting.
Biosolids are used for:
• land reclamation;
• mine reclamation;
• agricultural land fertilization; and
• forest fertilization.
• erosion control;
• horticulture;
• slope stabilization; and
• roadside aesthetic improvements.
The first pro to using biosolids as fertilizer is that it solves the sewage problem- after we dispose our wastes into our sewage, it does not magically disappear, for governments have to find somewhere to put it. Other considerations for solving sewage drainage is to incinerate it, or bury it in a landfill. Incinerating and burying the sewage can cause issues with the atmosphere and takes up valuable space. Recycling the biosolids as fertilizer on the other hand, is beneficial to stakeholders- farmers and gardeners, because it is inexpensive and organic.
This brings me to my next "pro", biosolids used as fertilizer improves and maintains soil and stimulates plant growth. In addition to this, biosolids are organic and contain many nutrients, such as nitrogen, phosphorus and potassium and trace elements such as calcium, copper, iron, magnesium, manganese, sulfur and zinc, which are essential for crop production and growth.
Cons of Biosolids
Although biosolids are high in nutrients, it can contain a multitude of metals, organic pollutants, and pathogens, which are harmful to us and the environment. A main concern on the issue of biosolids as fertilizers is that metals such as cadmium, zinc, and copper could build up to levels high enough to damage agricultural soils, causing long-term metal build-up.
In addition to this, there is controversy of biosolids negatively effecting soil organisms, soil processes, and fertility. It is proven that metals found in biosolids could have adverse effects on total soil microbial biomass,nitrogen fixation by cyanobacteria and by the nitrogen-fixing bacteria, Rhizobium.
Some scientists also believe biosolids used as fertilizer can cause a potential threat to water quality from leaching, erosion, or runoff losses.
Also, biosolid fertilizer can have a strong odor, which can be offensive to some people. Most of the odor from biosolids are from ammonia and sulfur compounds, plant nutrients.
Another concern addressing the use of biosolids are the pathogens: bacteria, viruses, protozoa, and helminth worms.
However, governments are currently regulating the uses of biosolids as fertilizers, checking and analyzing metal levels to ensure safe usage for the environment, those consuming the agricultural crops, and the stakeholders- farmers, gardeners, and the government, because they are responsible for the safety of their citizens.
In my opinion, I first found the use of biosolids as fertilizer unsanitary and disgusting because using human waste to fertilize our food is a daunting thought.
However, as I researched more about it, and learned it was treated, as our tap water is treated and cleaned, I became more open to the idea of biosolids fertilizer.
Although it is high in nutrients that are vital to plant growth, I do not believe biosolids should be used for agricultural fertilizer because even if it saves money and provides a solution for sewage waste, it can expose and release harmful pathogens and metals that will not be beneficial to anyone. The quote, "A team is only as strong as its weakest link" applies to biosolids because its most beneficial quality is only as advantageous as its worst quality. Therefore, I do not think governments should take the risk as to use biosolids as fertilizers when there are other alternatives- organic fertilizers such as compost in the situation.
What would you choose?
Commented on:
Amanda Phen http://www.bio4phen.blogspot.com/
Michael Ansell http://michael15ansell.blogspot.com/
Sources:
http://www.epa.gov/owm/mtb/biosolids/genqa.htm
http://docs.google.com/viewer?a=v&q=cache:ayTG0RNPYOAJ:www.compost.org/Biosolids_Composting_FAQ.pdf+stakeholder+of+biosolid+fertilizer&hl=en&gl=ca&pid=bl&srcid=ADGEESiovllwBAvwC5VHnPsQc3gj02-m8V2HXSsFMUAj7msduBIp_eyXEyO_Q02EgiPT3KzWSasrR0z1qgVoeB8EcPCBIRmE3-kLrtdP5dzFwn7q86E_iKKNjL55QeHiPyOj80M3VO0J&sig=AHIEtbTA5u7jCjJi8_azNDjuV8dXevPcFQ
http://www.mindfully.org/Pesticide/Sewage-Sludge-Pros-Cons.htm
http://webcache.googleusercontent.com/search?q=cache:UBQ9oI3kH9UJ:sospathogens.ifas.ufl.edu/PathogensandBiosolidslecture.ppt+biosolids+fertilizer+pathogens&cd=5&hl=en&ct=clnk&gl=ca
http://www.aces.edu/crd/publications/ANR-721.html
