Microbial risk assessment and mitigation options for wastewater treatment in Arctic Canada

Biological risk assessment in occupational settings currently is based on either qualitative or semiquantitative analysis. In this study, a quantitative microbial risk assessment (QMRA) has been applied to estimate the human adenovirus (HAdV) health risk due to bioaerosol exposure in a wastewater treatment plant (WWTP). A stochastic QMRA model was developed considering HAdV as the index pathogen, using its concentrations in different areas and published dose–response relationship for inhalation. A sensitivity analysis was employed to examine the impact of input parameters on health risk. The QMRA estimated a higher average risk in sewage influent and biological oxidation tanks (15.64% and 12.73% for an exposure of 3 min). Sensitivity analysis indicated HAdV concentration as a predominant factor in the estimated risk. QMRA results were used to calculate the exposure limits considering four different risk levels (one illness case per 100, 1.000, 10.000, and 100.000 workers): for 3 min exposures, we obtained 565, 170, 54, and 6 GC/m3 of HAdV. We also calculated the maximum time of exposure for each level for different areas. Our findings can be useful to better define the effectiveness of control measures, which would thus reduce the virus concentration or the exposure time.

Download Full-text

Quantitative microbial risk assessment of SARS-CoV-2 for workers in wastewater treatment plants

The Science of The Total Environment ◽

10.1016/j.scitotenv.2020.142163 ◽

2021 ◽

Vol 754 ◽

pp. 142163 ◽

Cited By ~ 1

Author(s):

Rafael Newton Zaneti ◽

Viviane Girardi ◽

Fernando Rosado Spilki ◽

Kristina Mena ◽

Ana Paula Campos Westphalen ◽

...

Keyword(s):

Risk Assessment ◽

Wastewater Treatment ◽

Wastewater Treatment Plants ◽

Quantitative Microbial Risk Assessment ◽

Microbial Risk Assessment ◽

Microbial Risk

Download Full-text

Sapovirus in Wastewater Treatment Plants in Tunisia: Prevalence, Removal, and Genetic Characterization

Applied and Environmental Microbiology ◽

10.1128/aem.02093-17 ◽

2018 ◽

Vol 84 (6) ◽

pp. e02093-17 ◽

Cited By ~ 11

Author(s):

Miguel F. Varela ◽

Imen Ouardani ◽

Tsuyoshi Kato ◽

Syunsuke Kadoya ◽

Mahjoub Aouni ◽

...

Keyword(s):

Risk Assessment ◽

Wastewater Treatment ◽

Bayesian Estimation ◽

Quantitative Pcr ◽

Censored Data ◽

Wastewater Treatment Plants ◽

Quantitative Microbial Risk Assessment ◽

Content Type ◽

Microbial Risk Assessment ◽

Microbial Risk

ABSTRACTSapovirus(SaV), from theCaliciviridaefamily, is a genus of enteric viruses that cause acute gastroenteritis. SaV is shed at high concentrations with feces into wastewater, which is usually discharged into aquatic environments or reused for irrigation without efficient treatments. This study analyzed the incidence of human SaV in four wastewater treatment plants from Tunisia during a period of 13 months (December 2009 to December 2010). Detection and quantification were carried out using reverse transcription-quantitative PCR (RT-qPCR) methods, obtaining a prevalence of 39.9% (87/218). Sixty-one positive samples were detected in untreated water and 26 positive samples in processed water. The Dekhila plant presented the highest contamination levels, with a 63.0% prevalence. A dominance of genotype I.2 was observed on 15 of the 24 positive samples that were genetically characterized. By a Bayesian estimation algorithm, the SaV density in wastewater was estimated using left-censored data sets. The mean value of log SaV concentration in untreated wastewater ranged between 2.7 and 4.5 logs. A virus removal efficiency of 0.2 log was calculated for the Dekhila plant as the log ratio posterior distributions between untreated and treated wastewater. Multiple quantitative values obtained in this study must be available in quantitative microbial risk assessment in Tunisia as parameter values reflecting local conditions.IMPORTANCEHuman sapovirus (SaV) is becoming more prevalent worldwide and organisms in this genus are recognized as emerging pathogens associated with human gastroenteritis. The present study describes novel findings on the prevalence, seasonality, and genotype distribution of SaV in Tunisia and Northern Africa. In addition, a statistical approximation using Bayesian estimation of the posterior predictive distribution (“left-censored” data) was employed to solve methodological problems related with the limit of quantification of the quantitative PCR (qPCR). This approach would be helpful for the future development of quantitative microbial risk assessment procedures for wastewater.

Download Full-text