The University of Arizona conducted this study in an attempt answer some of the most commonly asked questions regarding biosolids. Here are some of the questions answered by this study and presented in this factsheet.
- What Are Biosolids? (includes data - yeah!)
- What are the Biosolids Regulations?
- Land Application of Biosolids in Arizona and in the US
- History of Biosolids Research at the University of Arizona
- Biosolids Research in Arizona: Emerging Issues
- Biosolids Use for Land Reclamation
- Answers to Concerns about the Safety of Biosolids Land Use
- How can we contribute to the safe [use] of biosolids on land?
- Remember
- References and Websites of Interest
First, I love the Remember section and other blue-boxed sections:
- "As the population grows so will the production of biosolids and the need for safer disposal options.
Biosolids can continue to be valuable renewable source nutrients for agricultural soils, rangeland, and land reclamation as long as the quality of these residues continues to improve.
This can be done by controlling unwanted chemicals (metals, synthetic chemicals, medicines) in sewage streams and by improving biosolids pathogen and pollutant reduction methods."
- "Healthy soils contain hundreds of millions of beneficial bacteria and other microorganisms per gram that recycle plant nutrients, and degrade pathogens and organic pollutants.
Also, healthy soils usually have an excess capacity (minerals, organic matter and favorable chemical conditions) to trap and retain metals preventing them from contaminating plants and polluting other environments.
Soils can continue to provide this valuable service as long as they are not overwhelmed by excessive amounts of wastes, pollutants or other adverse soil conditions."
- "Biosolids are not a significant health threat as long as they are treated, stored, handled, and applied to land following accepted guidelines and regulations.
But, federal and state biosolids guidelines, regulations and monitoring programs must continue to evolve. They must adapt to new concerns about biosolids based on new scientific information."
Although worded very scientifically-jargonistically, the scientists concluded that:
- "Application of biosolids for nonfood agricultural crop production at this arid southwest site seems to be sustainable with respect to soil chemical entities."
- "The study showed that land application of Class B biosolids had no significant long-term effect on soil pH and CaCO3. However, land application significantly increased soil macro-nutrients (C, N and P). Soil nitrate values in plots that received biosolids or inorganic fertilizer amendments were high indicating the potential for groundwater contamination. In addition, total and available soil P concentrations increased to values above that necessary for plant growth but P values attenuated to background levels at a soil depth of 150 cm. Total metal concentrations attenuated rapidly with increasing soil depth, and were generally similar to values found in control soils at a depth of 150 cm."
- "Overall, the 20 annual land applications showed no long-term adverse effects, and therefore, this study documents that land application of biosolids at this particular site was sustainable throughout the 20-yr period, with respect to soil microbial properties."
- "Data show that land application of ClassB biosolids had no significant long-term effect on indigenous soil microbial numbers including bacteria, actinomycetes, and fungi compared to unamended control plots. Importantly, no bacterial or viral pathogens were detected in soil samples collected from biosolid amended plots in December (10 mo after the last land application) demonstrating that pathogens introduced via Class B biosolids only survived in soil transiently. However, plots that received biosolids had significantly higher microbial activity or potential for microbial transformations, including nitrification, sulfur oxidation, and dehydrogenase activity, than control plots and plots receiving inorganic fertilizers."
This section is also worth including. Consumer awareness, responsibility, and actions are critical for all environmental issues!
“What can be done to make biosolids a safer and more valuable fertilizer source?
- As end-users of numerous household products that contain toxic and hazardous chemicals, limiting the use and disposal of these products into the sewage system will continue to improve the quality of biosolids. What should we do?
- Use no or low phosphate, biodegradable soaps and detergents at manufacturer recommended amounts.
- Do not dump leftover household chemicals such as oil products, pesticides, paints, solvents and medicines down the toilet or sink. Instead, take unused or spent products to local recycling centers.
- Do not use or limit the outdoor use of yard pesticides and avoid chemical spills on driveways, as these activities can contaminate runoff water entering the sewage system.”
