Characterisation of indicator organisms and pathogens in domestic greywater for recycling.

Greywater from baths, showers and washbasins was collected at a University block of flats with a dual reticulation system and analysed for a range of contaminants including indicator organisms and pathogens. Plate counts and indicator organism concentrations were consistently high suggesting a high level of human bacterial contamination necessitating biological treatment and disinfection if greywater is to be used for recycling. However, these high levels of indicator organisms did not correlate to pathogen presence and should not be used as pathogen indicators in greywater. One positive count of Salmonella veltereden was observed as well as low levels of Giardia. Cryptosporidium, Escherichia coli O157:H7, enteroviruses and Legionella were not identified in any of the samples. Environ Monit Assess. 2007;129(1-3):61-9.