AWWA WQTC60712

Explosive population growth and diminishing freshwater resources around the globe have now made reclaimed water use an established practice in many parts of the world. Varieties of microbial pathogens are present in wastewater and can be detected in reclaimed water. The objective of this study was to evaluate changes in quality of reclaimed water as it passes through the reclaimed water distribution systems, from treatment plant to point of use, with particular reference to pathogen occurrence. The experimental approach includes evaluating treated reclaimed water samples monthly for five months from three different treatment facilities. However, currently only one system is participating in the sampling campaign and the other two systems are scheduled to participate in October 2004. The treatment facilities are located in three different states and reuse water for toilet flushing and cooling towers in a large apartment complex, shopping mall and a national stadium. The treatments include biological treatment, membrane filtration, ultraviolet light, ozone and chlorine disinfection. The samples were analyzed for the presence of total and fecal coliforms, E. coli, E.coli O157, Pseudomonas, Aeromonas, Legionella, HPC, somatic and male-specific coliphage, enteric virus (enterovirus, hepatitis A, norwalk virus, and rotavirus) nucleic acid by RT-PCR, Giardia cysts, infectious Cryptosporidium oocysts, and physiochemical water quality parameters. Water samples were positive for low levels of total and fecal coliforms, E. coli, and Pseudomonas, suggesting that regrowth may be occurring in the distribution system. Also one sample was positive for E. coli O157 indicating that additional disinfection may be necessary to ensure the safety of reuse water. Includes 10 references, tables.