A multi-scale approach was used to investigate the occurrence and physical characteristics of viral surrogates in water systems. This approach resulted in a methodology to quantify the dynamics and physical parameters of viral surrogates, including bacteriophages and nanoparticles. Physical parameters impacting the occurrence and survival of viruses can be incorporated into models that predict the levels of viral contamination in specific types of water. Multiple full-scale water systems (U.S., Italy and Australia) were tested including surface water, drinking water, stormwater and wastewater systems. Water quality parameters assessed included viral markers (TTV, polyomavirus, microviridae and adenovirus), bacteriophages (MS2 and ΦX-174), and coliforms (total coliforms and E. coli). In this study, the lack of correlations between adenovirus and that of bacterial indicators suggests that these bacterial indicators are not suitable as indicators of viral contamination. In the wastewater samples, microviridae were correlated to the adenovirus, polyomavirus, and TTV. While TTV may have some qualities which are consistent with an indicator such as physical similarity to enteric viruses and occurrence in populations worldwide, the use of TTV as an indicator may be limited as a result of the detection occurrence. The limitations of TTV may impede further analysis and other makers such as coliphages, and microviridae may be easier to study in the near future. Batch scale adsorption tests were conducted. Protein-coated latex nanospheres were used to model bacteriophages (MS2 and ΦX-174) and includes a comparison of the zeta potentials in lab water, and two artificial groundwaters with monovalent and divalent electrolytes. This research shows that protein-coated particles have higher average log10 removals than uncoated particles. Although, the method of fluorescently labeling nanoparticles may not provide consistent data at the nanoscale. The results show both that research on viruses at any scale can be difficult and that new methodologies are needed to analyze virus characteristics in water systems. A new dynamic light scattering methodology, area recorded generalized optical scattering (ARGOS) method, was developed for observing the dynamics of nanoparticles, including bacteriophages MS2 and ΦX-174. This method should be further utilized to predict virus fate and transport in environmental systems and through treatment processes. While the concentration of MS2 is higher than ΦX-174 as demonstrated by relative total intensity, the RMSD shows that the dynamics are greater and have more variation in ΦX-174 than MS2 and this may be a result of the hydrophobic nature of ΦX-174. Relationships such as these should be further explored, and may reflect relationships such as particle bonds or hydrophobicity.
Worcester Polytechnic Institute
Civil & Environmental Engineering
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Charest, A. J. (2015). Investigation of Physical Characteristics Impacting Fate and Transport of Viral Surrogates in Water Systems. Retrieved from https://digitalcommons.wpi.edu/etd-dissertations/54
Time-Dependent Light Scattering, Nanospheres, Bacteriophages, ARGOS method