We already know that biosolids are used as valuable fertilizer. Therefore, instead of taking up extra space in a landfill site or disposal facility, they can be put to much better use rather than having its fertilizer capability go to waste. Biosolids are used on farms and in gardens because applying biosolids reduces the need to apply chemical fertilizers. Chemical fertilizers are not the best option because excess applications of them tend to travel into groundwater, streams, lakes and eventually oceans thanks to the rain and irrigation. This results in pollution and damage to the natural environment. By using biosolids for agricultural use of crops, it has been found that they meet quality criteria and help to produce significant improvements when it comes to crop growth as well as yield.
An estimated 50% of all biosolids are recycled to land. As produced in a report in 2001 by the Water Environment Association of Ontario, it has been stated that biosolids are safe, conservative and do not show any significant risk to the environment or the health of humans if practices are followed properly.
CONS
Biosolids, as you might have guessed have a distinctive, smelly odor. They odor depends on the type of treatment it has undergone. Biosolids can smell only slightly disturbing or smell strongly disgusting to people. This odour is mostly caused by compounds of plant nutrients sulfur and ammonia. Though the smell can be reduced through management techniques, you cannot get rid of it completely and weather conditions can spread the odor.
Another disadvantage of biosolids is metals. Many metals may be essential for plant growth, however, there is a concern that large quantities of them can create problems for plants and animals. Therefore, the 503 regulations placed limitations on the amounts of metal which can be used for land application. These limits were created based on the lowest amount of a metal that would create a health problems for humans, plants and animals.
Too much of anything is not good. Over application of fertilizer nutrients can cause problems. For example, if the soil cannot store all of the nutrients, excess nitrogen or phosphorous can be absorbed by the surface/ground water. Over applications of nitrogen can lead to high nitrate concentrations in plants which can kill animals that eat it. However, nutrient management plans can help to use biosolids with other fertilizers to prevent this.
Pathogens (disease-producing agents) are a concern as well. However, there's a solution to those as well. Some biosolids are extensively treated to make sure there are no pathogens. Other biosolids are treated to reduce pathogen levels as well as well as they are to be used with soil to mix it up.
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Therefore, my take on biosolids is that they are good for our soils, even though they come with risks because after all, they are just RISKS and CONCERNS. Even though there are cons in the first place, they all have ways to reduce the potential to harm humans, plants and animals. Plus, biosolids have the ability to enhance plant growth, add nutrients to soil and restore mine sites instead of taking up extra space at a landfill site.
The stakeholders in this issue are the farmers, gardeners and the rest of us. Farmers decide whether they want to use biosolids for their crops and soil or not. Gardeners decide the same thing when it comes to their plants and the rest of us decide the same when it comes to our lawns since biosolids are safe to use. The choice is our own :)
Sources:
http://www.cwwa.ca/faqbiosolids_e.asp
http://www.your-healthy-gardens.com/fertilizers.html
http://pubs.ext.vt.edu/452/452-304/452-304.html
http://pubs.caes.uga.edu/caespubs/pubs/PDF/SB27.pdf