Effect of alternative on-site wastewater treatment on the viability and culturability of Salmonella choleraesuis

Abstract

The objective of this study was to determine how alternative on-site wastewater treatment systems (i.e. subsurface flow constructed wetlands, intermittent sand filters and intermittent peat filters) affect the viability and culturability of Salmonella choleraesuis (serotype typhimurium, ATCC 23567). Influent was a high strength septic tank effluent (BOD5 240-344 mgL(-1), TN approximately 100 mgL(-1), TP approximately 15 mgL(-1)) at the Natural Resources Research Institute's (NRRI) alternative treatment system test facility in northern Minnesota. Treatment systems were inoculated with cultures of S. choleraesuis for 5-7 consecutive days in summer and winter during 1998-99. After the seeding, outflow samples were taken until Salmonella counts were sustained at background levels. In addition to culture-based enumeration, S. choleraesuis abundances were also measured using fluorescent in situ hybridization (FISH) alone and in combination with the direct viable count method (DVC) to determine if plate counts underestimated total and viable Salmonella abundances and if the Salmonella cell viability changed after passing through the treatment systems. In most cases, total and viable cell abundances in treatment system effluents were several orders of magnitude higher than cultured cell abundances. Our results indicate that the culture-based method underestimated viable concentrations of the model pathogen, S. choleraesuis. Salmonella cell viability decreased in effluents during the summer but increased during the winter. Using a culture-based enumeration method alone to determine removal efficiencies of bacterial indicators and pathogens for wastewater treatment systems may result in artificially high estimates of effective treatment.

Culture‐Dependent and Culture‐Independent Nucleic‐Acid‐Based Methods Used in the Microbial Safety Assessment of Milk and Dairy Products

“…DVC is based on a revitalization step of the food sample in the presence of a gyrase inhibitor (such as nalidixic acid and ciprofloxacin for Gram‐negative and Gram‐positive bacteria, respectively) blocking DNA synthesis and preventing cell division without affecting other metabolic activities of cells that thereby elongate, with an accumulation of ribosomes (and intracellular rRNA contents). DVC can then be followed by FISH so that by using specific rRNA‐targeted oligonucleotide probes viable cells of the target bacteria can be detected and enumerated (Pundsack and others ; Wu and others ; Moreno and others ).…”

Perspectives on Advancing Sustainable CO2 Conversion Processes: Trinomial Technology, Environment, and Economy

“…In the indirect carbonation process mineral extraction is performed to increase the reaction rate between CO 2 and the cations, overcoming the limiting step in the direct carbonation process associated with the diffusion of the metal cations from the mineral lattice structure . Several mineral extraction mechanisms have been explored with varying challenges (mainly in terms of energy consumption and carbon footprint) dependent on the alkalinity source such as mechanical activation, , acid extraction, − thermal activation, , and the patented ammonium sulfate activation …”

Seasonal virus removal by alternative onsite wastewater treatment systems

“…fecal coliforms and E. coli). Recently, demonstration projects performed near Duluth, Minnesota, at a cluster CW treatment system at Grand Lake and at replicate residential sized systems at the North East Regional Correction Center (NERCC) research site showed them to be effective in removing fecal coliforms year round, but with reduced efficiency in the winter (McCarthy et al 1998(McCarthy et al , 1999Axler et al 2001;Henneck et al 2001;Monson-Geerts et al 2001;Pundsack et al 2001Pundsack et al , 2005. Traditional bacterial indicators have come under intense scrutiny as indicator organisms for human pathogens because of their lack of correlation with levels of enteric viruses and their low survivability in aquatic environments (Goyal & Gerba 1983;Stetler 1984;Havelaar et al 1993;Ferguson et al 1996;Calci et al 1998;Leclerc et al 2001).…”