Preferred bacteriological indicator of faecal contamination of water: March 2012
Ans: D i.e. E. coli The primary bacterial indicator recommended for acceptability purpose is the coliform group of organisms as a whole. The coliform group includes both faecal (E.coli) and non faecal organisms (Klebsiella aerogens) Supplementary indicator organisms, such as faecal streptococci and sulphite-reducing clostridia, may sometimes be useful in determining the origin of faecal pollution as well as in assessing the efficiency of water treatment processes.
Faecal streptococci
Cl. prefringens
Faecal staphylococci
E.coli