Stool to Cool

Since ancient times, manure from horses and cattle acted as a fertilizer when applied to crops, encouraging microbial activity and helping to retain moisture and mineral content. With the advent of biosolids becoming legalized in the United States in 1993, its use has been a debated topic among environmentalists and politicians alike. But what exactly are biosolids?

Above: Biosolids. It's pretty much the same as soil on a macroscopic level.

Biosolids as defined by the waste water industry, is a by-product of sewage and water treatment plants. It comes in various shapes and sizes, including blocks, pellets, and an aqueous solution. Unlike its name suggests, biosolids are not composed of human waste alone. Thousands of bacteria and microorganisms call biosolids their home, and not all of these are probiotic. In a study done by the United States of America in 2004, among 48 people who were surveyed, half of them were infected with various diseases, and a quarter of them were infected by staphylococcus aureus, a deadly bacteria that produces toxins known to cause hypertension, rash, and in extreme cases, multiple organ failure and death. This was exactly the outcome of 2 out of 48 people studied; they died from S. aureus.

Biological wastes aren't the only substances found in biosolids. Dissolved within the treated feces are heavy metal atoms, cadmium and copper to name a few. Some of these metals, such as copper, zinc, and nickel, are thought to have positive effects on plant growth, while others, such as mercury and arsenic, negatively affect plant growth. Luckily, the metals that are hazardous to plant life are in extremely tiny amounts, and do not have a noticeable effect on plant growth and germination, never mind humans.

Students at the University of Arizona published a paper regarding the effects of biosolids in the Arizonian environment. The paper states that "... land application of Class B biosolids had no significant long term effect on soil pH and CaCO₃." and goes on to say that "biosolids can provide much needed nutrients, and organic matter to these barren materials, increasing microbial activity and nutrient cycling for sustained plant growth."

With time, pressure, and a lot of care, even a piece of black coal can turn into a sparkling diamond. I believe that over time, as technology advances, we can eliminate further disasters like that in 2004. Managing biosolids will only get easier with time, and since it contributes positively to plant growth, I do not see why a restriction should be placed on these. After all, animal and plant wastes are returned to the earth in nature; why can't human waste do the same?


Sources

Artiola, Janick F. "Biosolid Land Use in Arizona." The University of Arizona.
     N.p., n.d. Web. 9 June 2011. <http://cals.arizona.edu/pubs/consumer/
     az1426.pdf>.

"Biosolids and Composting FAQ." Sylvis. N.p., n.d. Web. 9 June 2011.      <http://www.compost.org/Biosolids_Composting_FAQ.pdf>.

"Municipal Residuals Management & Biosolids Reduction." Siemens. N.p., n.d. Web.
     9 June 2011. <http://www.water.siemens.com/en/municipal/biosolids/Pages/
     default.aspx>.

"Standards for the Use or Disposal of Sewage Sludge." United States Code of
     Federal Regulations. N.p., n.d. Web. 9 June 2011.
     <http://edocket.access.gpo.gov/cfr_2003/julqtr/40cfr503.13.htm>.

"Water: Sewage Sludge (Biosolids)." United States Environmental Protection
     Agency. N.p., n.d. Web. 9 June 2011. <http://water.epa.gov/polwaste/
     wastewater/treatment/biosolids/index.cfm>. 


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