What are Coliphages?
Coliphages are a group of bacteriophages that infect and replicate within coliform bacteria. Male-specific coliphages infect only the E. coli bacteria that express certain physical appendages used during sexual conjugation (pili). Somatic coliphages adsorb directly into the E. coli cell wall. Both male-specific and somatic coliphages are used as surrogates to indicate the presence of fecal material and viral pathogens in water.
They are excellent candidates to determine log removal by treatment process, such as wastewater treated by UV, ozone, chlorine, and filtration. They have been suggested to be an alternative to human enteric virus testing for biosolids since they provide a more useful outcomes with quicker results and and are inexpensive to test for in relation to enteric viruses. Coliphages are detected using either a presence-absence assay (EPA method 1601) or an enumerative assay (EPA method 1602).
Coliphage Group Method Sample Volume Sample Matrix
Male-specific coliphages EPA 1601 100 ml /100 g SW DW WW BS*
Somatic coliphages EPA 1601 100 ml /100 g SW DW WW BS
Male-specific coliphages EPA 1602 100 ml SW DW WW
Somatic coliphages EPA 1602 100 ml SW DW WW
Male-specific coliphages EPA 1602 10-100L** SW DW WW
Somatic coliphages EPA 1602 10-100L SW DW WW
*: SW-surface water
**: including 5” positively charged capsule filter