AWWA PATH50800

The objective of this research was to compare bench-scale conventional and enhanced coagulation for removal of several emerging pathogens. For this research, enhanced coagulation refers to coagulation at pH 6.0, whereas conventional coagulation refers to coagulation at ambient source water pH. Waterborne viruses evaluted were Norwalk virus, adenovirus, poliovirus, and bacteriophage MS2. Bacterial pathogens evaluated were Escherichia coli O157:H7 and Eromonas hydrophila. Protozoan pathogens included in the study were Cryptosporidium parvum and Enterocytozoon intestinalis. Statistical tests indicated that the removal of Norwalk virus, adenovirus, poliovirus, bacteriophage MS2, and E. coli O157:H7 was significantly high at pH 6.0 than at ambient pH (pH 7.5¿0.1). Coagulation at pH 6.0 achieved an average log[10] removal of 1.6 of E. coli O157:H7, whereas coagulation at ambient pH achieved an average log removal of 0.9. For the viruses, the difference between enhanced and conventional coagulation varied from 0.3-logs for poliovirus to 1.1-logs for MS2. No statistically significant difference between enhanced and conventional coagulation was found for removal of Aeromonas hydrophila, Cryptosporidium parvum oocysts, and Enterocytozoon intestinalis spores. Includes 28 references, tables, figures.