Including Pathogen Risk in Life Cycle Assessment of Wastewater Management. 1. Estimating the Burden of Disease Associated with Pathogens

The environmental performance of wastewater and sewage sludge management is commonly assessed using life cycle assessment (LCA), whereas pathogen risk is evaluated with quantitative microbial risk assessment (QMRA). This study explored the application of QMRA methodology with intent to include pathogen risk in LCA and facilitate a comparison with other potential impacts on human health considered in LCA. Pathogen risk was estimated for a model wastewater treatment system (WWTS) located in an industrialized country and consisting of primary, secondary, and tertiary wastewater treatment, anaerobic sludge digestion, and land application of sewage sludge. The estimation was based on eight previous QMRA studies as well as parameter values taken from the literature. A total pathogen risk (expressed as burden of disease) on the order of 0.2–9 disability-adjusted life years (DALY) per year of operation was estimated for the model WWTS serving 28 600 persons and for the pathogens and exposure pathways included in this study. The comparison of pathogen risk with other potential impacts on human health considered in LCA is detailed in part 2 of this article series

A somatic coliphage threshold approach to improve the management of activated sludge wastewater treatment plant effluents in resource-limited regions

Versión aceptada para publicaciónEffective wastewater management is crucial to ensure the safety of water reuse projects and 29 effluent discharge into surface waters. Multiple studies have demonstrated that municipal 30 wastewater treatment with conventional activated sludge processes is inefficient for the removal 31 of the wide spectrum of viruses in sewage. In this study, a well-accepted statistical approach was 32 used to investigate the relationship between viral indicators and human enteric viruses during 33 wastewater treatment in a resource-limited region. Influent and effluent samples from five urban 34 wastewater treatment plants (WWTP) in Costa Rica were analyzed for somatic coliphage and 35 human enterovirus, hepatitis A virus, norovirus genotype I and II, and rotavirus. All WWTP 36 provide primary treatment followed by conventional activated sludge treatment prior to 37 discharge into surface waters that are indirectly used for agricultural irrigation. The results 38 revealed a statistically significant relationship between the detection of at least one of the five 39 human enteric viruses and somatic coliphage. Multiple logistic regression and Receiver Operating Characteristic curve analysis identified a threshold of 3.0 ×103 40 (3.5-log10) somatic 41 coliphage plaque forming unit per 100 mL, which corresponded to an increased likelihood of encountering enteric viruses above the limit of detection (>1.83×102 42 virus target/100 mL). 43 Additionally, quantitative microbial risk assessment was executed for famers indirectly reusing 44 WWTP effluent that met the proposed threshold. The resulting estimated median cumulative 45 annual disease burden complied with World Health Organization recommendations. Future 46 studies are needed to validate the proposed threshold for use in Costa Rica and other regions.Universidad de Costa Rica/[]/UCR/Costa RicaNational Science Foundation/[OCE-1566562]/NSF/Estados UnidosUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA)UCR::Vicerrectoría de Docencia::Salud::Facultad de Microbiologí