What type of bacteria serves as a common indicator of the effectiveness of water treatment?

Coliform bacteria are commonly used as indicators of water quality because their presence suggests that other pathogenic organisms may also be present in the water. These bacteria are a group that includes various species, such as Escherichia coli (E. coli) and Enterobacter, which are normally found in the intestines of warm-blooded animals.

Water treatment processes, including filtration and disinfection, aim to remove or kill these bacteria. If coliform bacteria are detected in treated water, it raises concerns about the water's safety and indicates that the treatment process may not have been effective in eliminating harmful pathogens, including viruses and protozoa.

Using coliform bacteria as indicators is advantageous because they are easier to detect and assess than many other pathogens, allowing for quicker responses to potential water quality issues. In contrast, other options like helminths and Salmonella are not routinely used as indicators for the effectiveness of water treatment processes for various reasons, including complexity in detection and their different environmental behaviors.