Rj. Daviescolley et al., SUNLIGHT WAVELENGTHS INACTIVATING FECAL INDICATOR MICROORGANISMS IN WASTE STABILIZATION PONDS, Water science and technology, 35(11-12), 1997, pp. 219-225
Citations number
18
Categorie Soggetti
Water Resources","Environmental Sciences","Engineering, Civil
Waste stabilisation ponds (WSPs) are widely used in New Zealand for th
e treatment of domestic sewage and other organic wastes. Traditionally
, faecal coliforms have been used as the faecal indicator in WSPs and
their receiving waters but there is increasing interest in alternative
indicators. We studied the comparative inactivation kinetics under su
nlight of two bacterial indicators in WSP effluent, and also those of
two F-specific bacteriophages that may be models of the behaviour of v
iral pathogens in WSPs. We investigated the wavelength-dependence of s
unlight inactivation in rapidly-stirred, small reactors, with temperat
ure, dissolved oxygen and pH control, using various plastics as ''long
pass'' filters to screen different portions of the UV-visible spectrum
. The UVB, UVA and blue-green visible radiation (<550nm wavelength) al
l contributed appreciably to inactivation of enterococci and possibly
FRNA phage, consistent with a photooxidation mechanism of action. In c
ontrast, E. roll and presumed FDNA phage were inactivated mainly by WE
, consistent with direct absorption by, and damage to, the DNA with mi
nor or negligible contribution by longer wavelengths. Our results sugg
est that E. coli may be a better bacterial indicator in WSPs than ente
rococci. (C) 1997 IAWQ. Published by Elsevier Science Ltd.