COMPARISON OF CULTURAL METHODS ON BACTERIAL RECOVERY IN SOURCE WATER FOR WATER SUPPLY

The quality of source water for water supply is the basic indicator of the choice of treatment technology, and the change of that quality is one of the main causes of worsening the quality of tap water. Having an objective to define the most adequate cultural method for determination of aerobic mesophilic bacterial count, i.e. to estimate bacteriological load of source water for water supply, a total of 283 samples from Celije Reservoir were collected. The samples were simultaneously inoculated on high-nutritive PCA medium and low-nutritive R2A medium, and incubated for 7 days at room temperature (22C). The bacterial count was recorded after 48, 72, 120 and 168 hours (7 days) of incubation. The superiority of R2A medium with all durations of incubation period was established, so that this medium is recommended as that of choice for monitoring the general microbiological quality of source water. The most authentic picture of bacterial load of the source is obtained after 7-day incubation, but, if rapid results are required, the incubation period can be shortened to not less than 72 hours.