Reduction of Human Enteric and Indicator Viruses at a Wastewater Treatment Plant in Southern Louisiana, USA

This study assessed wastewater quality through the quantification of four human enteric viruses and the applicability of pepper mild mottle virus (PMMoV) and tobacco mosaic virus (TMV) as indicators of viral reduction during wastewater treatment. Thirty-three samples were collected from three steps of a wastewater treatment plant in Southern Louisiana, USA for a year between March 2017 and February 2018. Noroviruses of genogroup I were the most prevalent human enteric viruses in influent samples. The concentrations of PMMoV in influent samples (5.9 +/- 0.7 log(10)copies/L) and biologically treated effluent samples (5.9 +/- 0.5 log(10)copies/L) were significantly higher than those of TMV (P < 0.05), and the reduction ratio of PMMoV (1.0 +/- 0.8 log(10)) was found comparable to those of TMV and Aichi virus 1. Because of the high prevalence, high correlations with human enteric viruses, and lower reduction ratios, PMMoV was deemed an appropriate indicator of human enteric viral reduction during wastewater treatment process.