A newly published report from a University of Arizona research group says biosolids, properly treated, pose little if any health risk to the public. The study, "Pathogens in Biosolids: Are They Safe?," is online in the Journal of Environmental Quality.
Ian L. Pepper, director of the NSF Water and Environmental Technology Center and a professor of soil, water and environmental science, or SWES, at the UA, led the study, a 19-year analysis tracking pathogens in biosolids from the wastewater stream in Tucson, Ariz. The study also included current data from 18 other wastewater treatment plants across the country.
The study's co-authors include another SWES professor, Charles P. Gerba, as well as researchers from the U.S. Department of Agriculture, Loma Linda University and Drexel University. The study is the first of its kind since current federal regulations, specifically the Environmental Protection Agency's Part 503 Rule, for wastewater treatment began in 1993.
The Part 503 Rule governs how wastewater is treated in order to maintain public and environmental safety.
Most people in the U.S. live in communities where raw sewage is treated at wastewater facilities. Biosolids, the end product of the treatment process, have a broad range of uses in agriculture, from fertilizing agricultural fields and woodlands to lawns and gardens. Biosolids fall into two categories, Class A and Class B. Both use a combination of processes to kill pathogens including heating, composting, anaerobic digestion or changing pH levels.
Class A biosolids are those that have been treated to the point where pathogens are undetectable and there are no restrictions on their use as fertilizer. Standards for Class B biosolids are less stringent and have small but measurable levels of bacteria and come with restrictions on how they can be used on crop plants, grazing livestock and human exposure.
Pepper said one big question has been what kind and how many human pathogens are found in Class B biosolids. He said the study analyzed data prior to and after 1993, when the Part 503 rule took effect in order to determine the impact of regulations.
The study, Pepper said, showed that concentrations of fecal coliform bacteria and viruses are actually lower than 1993 levels. It also showed that between 94 and 99 percent of pathogens are eliminated by wastewater treatment, crediting treatment in reducing pathogen loads.
"Further, the fact that pathogen levels are lower now than in the 1980s shows that the Part 503 Rule has been effective in reducing public exposure to pathogens relative to 25 years ago," he said.
The study suggests that levels of some enteric viruses, the bacteria Salmonella and Ascaris ova, or roundworm eggs, in the U.S. are low in Class B biosolids that are treated by anaerobic digestion. Pepper and his colleagues also found no Campylobacter or E. coli bacteria in their tests.
Other studies suggest that Class B biosolids also are treated further simply by exposure to sunlight, wind, heat and soil microbes as they are distributed as fertilizer. Using biosolids as fertilizer also is a more ecologically sound approach to their disposal than either taking up space in landfills or polluting air and water through incineration.
The UA Water and Environmental Technology Center has gained a nationwide reputation for research on biosolids by providing data on human exposure to microbial pathogens, allowing for risk assessments on potential adverse effects of pathogens on human health and welfare.
Contact:Ian L. Pepper
| University of Arizona
Energy crop production on conservation lands may not boost greenhouse gases
13.03.2017 | Penn State
How nature creates forest diversity
07.03.2017 | International Institute for Applied Systems Analysis (IIASA)
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
30.03.2017 | Health and Medicine
30.03.2017 | Health and Medicine
30.03.2017 | Medical Engineering