Master of Science (MS)


Environmental Sciences

Document Type



Cryptosporidium is a common protozoan parasite that causes cryptosporidiosis, a severe gastrointestinal disease. Currently, there is no antibiotic available to treat the disease. Cryptosporidium has been responsible for several waterborne disease outbreaks in the United States. The largest cryptosporidiosis outbreak in United States history occurred in Milwaukee, Wisconsin in spring 1993. The vulnerability of the United State drinking water supply to waterborne disease outbreak is still prevalent nearly 15 years after the Milwaukee outbreak. In order to effectively control Cryptosporidium, the EPA has strengthened the regulations on turbidity control for filtration performance by implementing the Long Term 1 Enhanced Surface Water Treatment Rule. The Long Term 1 Enhanced Surface Water Treatment Rule applies to all public water systems that serve fewer than 10,000 people and use surface water or ground water under the direct influence of surface water. The turbidity level of combined filter effluent water samples must be less than or equal to 0.3 NTU in at least 95% of the measurements taken each month, with no samples exceeding 1 NTU. Systems meeting these filter performance requirements are presumed to achieve at least a 2-log removal (99%) of Cryptosporidium. The purpose of this research is to evaluate compliance with the Long Term 1 Enhanced Surface Water Treatment Rule for a potable water treatment system operated by an oil refinery in southeast Louisiana that has been experiencing turbidity spikes since February 2006. The turbidity and disinfection data obtained from this facility will be examined. This study found that, despite meeting compliance requirements of the Long Term 1 Enhanced Surface Water Treatment Rule, there were still several areas of concern within the treatment process. Additional information is needed to determine the effectiveness of the turbidity data management tool. The regression analysis showed that raw water turbidity could not accurately predict daily average turbidity. Recommendations were made regarding comprehensive system evaluation, monitoring, improvements in treatment technique, and best practices. Although this study concluded in September 2006, significant improvements were made to the gravity sand filters. In April 2007, an ultrafiltration system replaced the gravity sand filters in the potable water treatment system.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Margaret A. Reams