B056 Institution water quality

A pilot study of microbiological water quality in an institutional building

Brief:

Microbiological water quality can be an indicator for the deterioration of a drinking water system and of health concerns. An outbreak of waterborne infectious diseases would be closely related to the microbiological water quality. This study investigates the microbiological water quality of two drinking water systems in an institutional building: system (1) is an ultraviolet filtration system from a potable water supply, and system (2) is a bottle of 19L water with a distilled water dispenser. Water samples of 100ml were collected from both systems in the same period and heterotrophic plate counts (HPC) for bacteria and fungi were investigated. It was reported that no fungi were detected in all water samples. The results reported that the average HPC bacteria level of system (1) was 27±8 CFU ml^-1, which was significantly lower than the sample of 74 CFU ml^-1 collected from system (2). Furthermore, it was reported that, for system (1), a probable down trend of HPC bacteria level in the water samples collected in a day in the system was observed (p<0.2). Probably, the amplification and accumulation of bacteria in the water distribution system during periods of low water demand was diluted by the fresh water from the city mains during normal water demands. A total of eight bacterial genera were isolated; 98% isolates in system (1) and 73% in system (2) were gram-negative bacteria. This pilot study would be useful for further water quality investigations on the installation and operation of drinking water systems in institutional buildings.

Further Information:

Chan WY, Mui KW, Wong LT, 2007. A pilot study of microbiological water quality in an institutional building, Joint Symposium 2007 on Building Services Engineering for a World Class City, 13 November, Kowloon Shangri-la Hotel, Hong Kong, pp. 123-128.