TY - JOUR
T1 - Chlorination of indicator bacteria and viruses in primary sewage effluent
AU - Tree, Julia
AU - Adams, Martin R.
AU - Lees, David N.
PY - 2003/4/1
Y1 - 2003/4/1
N2 - Wastewater disinfection is used in many countries for reducing fecal coliform levels in effluents. Disinfection is therefore frequently used to improve recreational bathing waters which do not comply with microbiological standards. It is unknown whether human enteric viruses (which are responsible for waterborne disease) are simultaneously inactivated alongside fecal coliforms. This laboratory study focused on the chlorination of primary treated effluent with three doses (8, 16, and 30 mg/liter) of free chlorine as sodium hypochlorite. Seeding experiments showed that inactivation (>5 log10 units) of Escherichia coli and Enterococcusfaecalis was rapid and complete but that there was poor inactivation (0.2 to 1.0 log10 unit) of F+-specific RNA (FRNA) bacteriophage (MS2) (a potential virus indicator) at all three doses. However, seeded poliovirus was significantly more susceptible (2.8 log10 units) to inactivation by chlorine than was the FRNA bacteriophage. To ensure that these results were not artifacts of the seeding process, comparisons were made between inactivation rates of laboratory-seeded organisms in sterilized sewage and inactivation rates of organisms occurring naturally in sewage. Multifactorial analysis of variance showed that there was no significant difference (P > 0.05) between the inactivation rates for seeded and naturally occurring FRNA bacteriophage. However, laboratory-grown poliovirus was inactivated much more rapidly than were naturally occurring, indigenous enteroviruses (P < 0.001). This may reflect differences in the way indigenous virus is presented to the disinfectant. Inactivation rates for indigenous enteroviruses were quite similar to those seen for FRNA bacteriophage at lower doses of chlorine. These results have significance for the effectiveness of chlorination as a sewage treatment process, particularly where virus contamination is of concern, and suggest that FRNA bacteriophage would be an appropriate indicator of such viral inactivation under field conditions.
AB - Wastewater disinfection is used in many countries for reducing fecal coliform levels in effluents. Disinfection is therefore frequently used to improve recreational bathing waters which do not comply with microbiological standards. It is unknown whether human enteric viruses (which are responsible for waterborne disease) are simultaneously inactivated alongside fecal coliforms. This laboratory study focused on the chlorination of primary treated effluent with three doses (8, 16, and 30 mg/liter) of free chlorine as sodium hypochlorite. Seeding experiments showed that inactivation (>5 log10 units) of Escherichia coli and Enterococcusfaecalis was rapid and complete but that there was poor inactivation (0.2 to 1.0 log10 unit) of F+-specific RNA (FRNA) bacteriophage (MS2) (a potential virus indicator) at all three doses. However, seeded poliovirus was significantly more susceptible (2.8 log10 units) to inactivation by chlorine than was the FRNA bacteriophage. To ensure that these results were not artifacts of the seeding process, comparisons were made between inactivation rates of laboratory-seeded organisms in sterilized sewage and inactivation rates of organisms occurring naturally in sewage. Multifactorial analysis of variance showed that there was no significant difference (P > 0.05) between the inactivation rates for seeded and naturally occurring FRNA bacteriophage. However, laboratory-grown poliovirus was inactivated much more rapidly than were naturally occurring, indigenous enteroviruses (P < 0.001). This may reflect differences in the way indigenous virus is presented to the disinfectant. Inactivation rates for indigenous enteroviruses were quite similar to those seen for FRNA bacteriophage at lower doses of chlorine. These results have significance for the effectiveness of chlorination as a sewage treatment process, particularly where virus contamination is of concern, and suggest that FRNA bacteriophage would be an appropriate indicator of such viral inactivation under field conditions.
UR - http://www.scopus.com/inward/record.url?scp=0242668354&partnerID=8YFLogxK
U2 - 10.1128/AEM.69.4.2038-2043.2003
DO - 10.1128/AEM.69.4.2038-2043.2003
M3 - Article
C2 - 12676680
AN - SCOPUS:0242668354
VL - 69
SP - 2038
EP - 2043
JO - Applied and Environmental Microbiology
JF - Applied and Environmental Microbiology
SN - 0099-2240
IS - 4
ER -