Date of Award

Spring 1998

Project Type

Dissertation

Program or Major

Microbiology

Degree Name

Doctor of Philosophy

First Advisor

Aaron Margolin

Abstract

The Environmental Protection Agency (EPA) continues to establish criteria for the reduction of pathogens in environmental waters used for drinking water. The EPA also states criteria on the amount of chlorine by-products allowed in drinking water. Alternative removal methods that are used in conjunction with chlorine are needed to assure safe drinking water.

The Surface Water Treatment Rule (SWTR) states that a 99.99% reduction of viruses and a 99.9% reduction in Giardia lamblia cysts needs to be achieved by a treatment facility that uses surface water for the production of drinking water. The SWTR also states Maximum Contaminant Levels (MCL) on trihalomethane production. The Groundwater Disinfection Rule (GWDR) states that a 99.99% reduction of viruses must be achieved in treatment facilities using groundwater for the production of drinking water.

The ability of polysulfone hollow fiber (HF) ultrafiltration (UF) membranes to remove bacteriophage, MS2, Giardia lamblia cysts, and Cryptosporidium parvum oocysts from MilliQ water was examined. The membranes were placed in a Koch 5 bench scale disinfection unit. Operating conditions such as transmembrane pressure, pH, and temperature were varied to assess their effects on removal capability. A 100,000D PMPW membrane consistently removed 99.99% of MS2 titer and 99.999% of G. lamblia cysts and C. parvum oocysts under different operating conditions. The PMPW membrane achieved a 99.99% removal of MS2 in trials where MS2 was continually added to the influent at a concentration of $1.73\times10\sp4$ pfu/ml-min.

Ultraviolet (UV) irradiation was assessed for its ability to inactivate MS2, poliovirus LSc-1, hepatitis A virus HM-175, and rotavirus Wa in bench scale petri dish assays. Known concentrations of these viruses were added to MilliQ water and different groundwaters and UV irradiated. The least susceptible virus to UV irradiation was rotavirus Wa strain. In MilliQ water and groundwater, 99.99% reductions in titer occurred at 97.0 mWs/cm$\sp2.$ A 99.99% reduction in MS2 occurred at 80 mWs/cm$\sp2$ in MilliQ water and between 64.0 mWs/cm$\sp2$ and 93.0 mWs/cm$\sp2$ in groundwaters. Poliovirus and hepatitis A virus were considerably less resistant to UV inactivation. A cell culture-RT PCR assay was used to determine rotavirus Wa titers before and after UV irradiation.

Filtration was capable of meeting the pathogen removal criteria stated in the SWTR. UV irradiation met the virus inactivation criteria stated in the GWDR. Both methodologies could be used in full scale treatment plants under controlled conditions to determine their ability to remove pathogens from drinking water.

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