Which method is commonly used for testing microbial contaminants in water?

The method commonly used for testing microbial contaminants in water is membrane filtration. This technique involves passing a water sample through a membrane that has specific pore sizes, which allows for the retention of bacteria and other microorganisms on the membrane’s surface. After filtration, the membrane is placed on a suitable growth medium and incubated, allowing any viable microorganisms to grow into colonies. This facilitates quantification and identification of the microbial contamination present in the water sample.

Membrane filtration is favored in water quality testing because it provides a relatively quick and direct method to isolate and enumerate bacteria, including pathogenic species. It is particularly effective for assessing the microbiological quality of drinking water and recreational water sources.

Other methods, such as ultrafiltration, are generally used for separating particles based on size but are not specifically designed for microbial testing. Gravity filtration primarily removes larger particulates and sediments but lacks the specificity for microbial detection. Chlorination is a disinfection process used to kill microorganisms in water but does not serve as a testing method for detecting their presence.