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Biosolids Publications Viau, E. and Peccia J. (2009) "Evaluation of the enterococci indicator in biosolids using culture-based and quantitative PCR assays" Water Research, 43, 4878-4887.pdf Viau, E. and Peccia, J. (2009) "A survey of wastewater indicators and human pathogen genomes in biosolids produced by Class A and Class B stabilization treatments," Applied and Environmental Microbiology, 75, 164-174. pdf
Baertsch, C., Paez-Rubio, T., Viau, E., Peccia, J. (2007) “Source tracking aerosols released from land-applied class B biosolids during high wind events," Applied and Environmental Microbiology,73, 4522-4531.pdf
Low, S.Y., Paez-Rubio, T., Baertsch, C., Kucharski, M., Peccia, J. (2007) “Off-site exposure to respirable aerosols produced during the disk-incorporation of class B biosolids” Journal of Environmental Engineering. 133. pdf
Paez-Rubio, T., Ramarui, A., Sommer, J., Xin, H., Anderson, J. and Peccia, J. (2007) “Emission rates and characterization of aerosols produced during the spreading of dewatered class B biosolids” Environmental Science and Technology, 41, 3537-3544. pdf Paez-Rubio, T., Xin, H., Anderson J., Peccia, J. (2006). “Particulate matter composition and emission rates from the disk incorporation of class B biosolids into soil” Atmospheric Environment. 36: 7034-7045.pdf Paez-Rubio, T and J. Peccia (2004). “Estimating solar inactivation rates of airborne bacteria” Journal of Environmental Engineering : 131: 512-517.pdf
Funding National Science Foundation Water Environment Research Foundation U.S.A-Israel BARD
Volatile Fatty Acid Inactivation |
Current Research
Industrial and domestic wastewater in the United States is treated by both physical removal and the biological transformation of organic compounds and nutrients to less environmentally harmful forms. The sludge removed during a primary sedimentation step and the settled microorganisms produced during biological transformations are collectively called “solids” and form their own separate waste stream. The U.S. EPA estimates that this amount of biosolids produced in the US will grow to 8.2 million tons per year by 2010. In 2000, approximately 5 million tons of biosolids were applied to agricultural lands in 40 states. The beneficial use of biosolids in the U.S., however, is a present environmental, public health, and public acceptance concern. Research in the last five years has made significant progress on estimating the human exposure to total biosolids aerosols and biosolids indicator microorganisms. Advances include both the development and calibration of theoretical and empirically-based microbial aerosol models to assess off-site exposure during land application operations and application of culture and DNA-based microbial source tracking methods to these aerosols. Based on the results of our field experiment, we have identified methods to estimate the amount of respirable pathogens that an off-site stationary receptor would inhale during a land application event. Our most current research focuses on (i) identifying viral and bacterial pathogens in a diversity of class A and class B biosolids, (ii) estimating the in vitro toxicity of biosolids aerosols, and (iii) describing the energy requirements of effective class A and class B stabilization methods. Viral and Bacterial Pathogen Surveys: We have looked for pathogens in biosolids from over 30 different treatment facilities producing class A and class B biosolids.The figure below describes the total concentrations (by quantitative PCR) of some of these pathogens.
Pathogen content by qPCR of class A and class B biosolids from over 30 North American treatment facilities.
In vitro toxicity: By exposing normal human lung cells (BEAS-2B) to aerosolized class A and class B biosolids we are testing for the in vitro toxicity (cytotoxicity and cytokine induction). Our preliminary results indicate that the order of toxicity for differently stabilized biosolids from greatest toxicity to least toxicity is mesophilic anaerobic digestion>thermophilic anaerobic digestion>composting. The cytotoxicity and cytokine induction from biosolids-derived aerosols is greater than that of soils and similar to that caused by agricultural manures. This work is being performed in collaboration with Dr. Francesca Levi-Shaffer at Hebrew University in Jerusalem Israel.
Pathogen stabilization effectiveness: Our final research thrusts in this area are (i) studying how viruses are inactivated through standard biosolids stabilization processes and how this inactivation compares with that of fecal coliform bacteria, (ii) determining how fatty acids produced during phased digestion can provide a low energy alternative to pathogen stabilization during anaerobic digestion, (iii) determining the relationship between energy utilization and pathogen concentration in heated anaerobic digeters.. |
