Managing risks from virus intrusion into water distribution systems due to pressure transients.
J Water Health
; 9(2): 291-305, 2011 Jun.
Article
em En
| MEDLINE
| ID: mdl-21942194
ABSTRACT
Low or negative pressure transients in water distribution systems, caused by unexpected events (e.g. power outages) or routine operation/maintenance activities, are usually brief and thus are rarely monitored or alarmed. Previous studies have shown connections between negative pressure events in water distribution systems and potential public health consequences. Using a quantitative microbial risk assessment (QMRA) model previously developed, various factors driving the risk of viral infection from intrusion were evaluated, including virus concentrations external to the distribution system, maintenance of a disinfectant residual, leak orifice sizes, the duration and the number of nodes drawing negative pressures. The most sensitive factors were the duration and the number of nodes drawing negative pressures, indicating that mitigation practices should be targeted to alleviate the severity of low/negative pressure transients. Maintaining a free chlorine residual of 0.2 mg/L or above is the last defense against the risk of viral infection due to negative pressure transients. Maintaining a chloramine residual did not appear to significantly reduce the risk. The effectiveness of ensuring separation distances from sewer mains to reduce the risk of infection may be system-specific. Leak detection/repair and cross-connection control should be prioritized in areas vulnerable to negative pressure transients.
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Base de dados:
MEDLINE
Assunto principal:
Esgotos
/
Microbiologia da Água
/
Abastecimento de Água
/
Norovirus
/
Exposição Ambiental
/
Água Doce
Tipo de estudo:
Etiology_studies
/
Health_economic_evaluation
/
Prognostic_studies
/
Risk_factors_studies
Limite:
Humans
País como assunto:
America do norte
Idioma:
En
Ano de publicação:
2011
Tipo de documento:
Article