Date of Award

2020

Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy in Environmental Engineering (PhD)

Administrative Home Department

Department of Civil and Environmental Engineering

Advisor 1

Veronica Webster

Advisor 2

Caryn Heldt

Committee Member 1

Sharon Long

Committee Member 2

Paul Doskey

Abstract

Infectious diseases are a significant threat to public health. Though society enacts practices to prevent the spread of these dangerous diseases, challenges remain. Therefore, continual advancements in treatment and prevention are required. Wastewater treatment and viral clearance in pharmaceutical applications are two key health measures that prevent the spread of infections.

A low-cost, low-technology biosolids treatment process was developed to improve wastewater treatment by collecting key information on storage temperature, ammonia, volatile solids, moisture content, pH, and pathogen inactivation in biosolids over long-term storage at two wastewater treatment plants located in northern climates of the United States. Inactivation of pathogens in the biosolids was enhanced by freeze-thaw cycles, intermediate moisture contents (16% total solids), and time. Biosolids required over a year of long-term storage to reach standard pathogen limits for treatment in northern climates.

To improve viral clearance in therapeutic protein manufacturing, the use of arginine and buffers was studied at pH ≥ 4 to retain the stability of the final protein product. A stabilized virus membrane structure, resulting from lipid packing density or membrane proteins, hindered the inactivation efficacy of arginine and buffers. The influence of membrane properties on arginine and buffer interactions supports the inactivation mechanisms of viral membrane deformation. Increased hydrophobicity and clustering enhanced the inactivation of enveloped viruses by arginine at pH 4 and 7. Electrostatic interactions increased the inactivation of enveloped viruses by buffers at pH 4.

Overall, the mechanisms for pathogen inactivation were further understood for the improvement of biosolids treatment and therapeutic protein manufacturing to facilitate the prevention of infectious diseases.

Available for download on Tuesday, December 01, 2020

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