Wastewater biosolids go through several processes in order to eliminate pathogens. I won’t go into a very detailed description of it, but I will give you a generalization of it. Their treatment can begin even before the wastewater reaches the sewage plant. This wastewater would be pre-treated in order to remove many hazardous contaminants before it is sent to a wastewater treatment plant. Then, when it reaches its destination at the wastewater plant, the sewage goes through physical, chemical, and biological processes which clean the wastewater and removes the solids. Then if it is necessary, the solids are treated with lime to raise the pH level. This would eliminate any offensive odours. The wastewater solids would than be sanitized through these processes to control pathogens and other organisms capable of transporting disease.
When it comes down to the pros and cons of using this agricultural practice, there are many for both sides. For now, I will focus on the pros. First of all, creating this fertilizer will create many job opportunities for people, as would almost any job. It could also potentially promote more farming. By treating sewage sludge, it can be turned into valuable fertilizer instead of taking up space in a landfill or other disposal factory. It also reduces the need for chemical fertilizers. The use of biosolids reduces the farmer's production costs and replenishes the organic matter that has been dwindling over time. The organic matter improves soil structure by increasing the soil's ability to absorb and store moisture. The organic nitrogen and phosphorous found in biosolids are used very efficiently by crops because these plant nutrients are released slowly throughout the growing season. This enables the crop to absorb these nutrients as the crop grows. This efficiency lessens the likelihood of groundwater pollution of nitrogen and phosphorous. Lastly, it can also promote rapid timber and plant growth, and regenerates mine sites due to the renewal it creates. An undeniable characteristic of biosolids is that the organic matter and complement of essential nutrients in them can’t be duplicated by synthetic fertilizers. Biosolids beyond question have a lot of benefits, and contribute to waste reduction and nutrient recycling. “Biosolids are like vitamin pills for soil.” - Ken Arnold. Of course, despite how many pros may be present, there are always cons that follow. The cons are that some biosolids may have a slight musty, ammonia odour. Some may have a stronger smell than others, and this may be offensive to some people. Studies show that chemicals such as lime, which is added during sludge processing, can irritate the skin and respiratory tract and make people more susceptible to infection. Sludge also has traces of household chemicals poured down drains, detergents from washing machines, heavy metals from industry, synthetic hormones from birth control pills, pesticides, and dioxins, which are a group of compounds that have been linked to cancer. Another con is that excessive amounts of this organic fertilizer can also result in nitrate contamination of surface and groundwater. As well, the accumulation of industrial waste can result in contamination. Overall, since its true composition is unknown, its effects are truly unknown. There are some potential health hazards linked to biosolids, and these effects can in the long run end up being irreversible.
SOURCES:
http://scijourner.org/index.php?option=com_content&view=article&id=34:from-toilet-to-table-biosolids-for-fertilizer&catid=13:technology&Itemid=40
http://www.epa.gov/OWM/mtb/biosolids/genqa.htm
http://lancaster.unl.edu/enviro/biosolids/fertil.shtml
http://www.aces.edu/crd/publications/ANR-721.html
3 comments:
Last blog, hurrah! (: You know, bio-solids, as we have both mentioned is very beneficial. True, we don't know the long term effects of it, but if you look at it, it is way better than if we keep using those fertilizers that are inorganic. Sooner or later, all the farmlands that is used at this moment would loose its capability of producing. If we don't stop using them now they could lead to even more disastrous consequences in the future. I like that quote you used by the way, saying, “Biosolids are like vitamin pills for the soil”. It’s so true! I mean, not only that it fertilizes the soil organically, we also keep the junk from our sewers away from the body of waters. I mean, we have stopped dumping them into the lakes and the oceans, but we have no where else to put the waste that have been treated to clean the sludge. Why shouldn’t we use it? Yes, it is smelly, like you said, but very beneficial. But you know what they say; no pain, no gain… :D Thank you for your blog post, it’s very entertaining!
You said at the beginning of your blog entry that prior to this blog, you have never heard of biosolids. In my case, I've heard of this way before. In the Philippines, some decades ago, this practice is popular to farmers. But as time passed by, they turned to chemical fertilizers as they became more and more popular. I will not bore you about what happened next but now that we're investigating the pros and cons of biosolids, I think that it was just a shame that those Filipino farmers turned their backs in the development of proper use of biosolids as fertilizers.
Anyway, my standpoint on this issue is that biosolids are more beneficial than harmful. I think that we are better off using biosolids rather than those chemical ones. They are more expensive and produces more harmful and toxic by-products when manudfactured.
I also like the quote you included in your blog that says, "Biosolids are like vitamin pills for the soil." It's a very interesting and clever analogy for biosolids.
I think I've wrote what I wanted to say. Good job on your blog. Good luck to all of us!
Great job, Stephanie! This is one of your best post so far! :)
Anyhow, one thing I did forget to mention on my blog is that biosolids are great replacements for chemical fertilizers that most farmers use today. Also, I could see the point of view of those who are against biosolids and see them as disgusting and awfully smelly, but I think that we should see past it since they are a great way of recycling wastes. I can't say this enough: we finally found some use of human wastes and just as you said, "why not give this a shot?"
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