Correlation between bacterial indicators and bacteriophages in sewage and sludge

Area of Science:

• Environmental microbiology
• Water quality assessment
• Microbial pollution detection

Background:

• Fecal pollution in water sources is a significant public health concern.
• Traditional bacterial indicators have limitations in accurately reflecting pollution levels.
• Bacteriophages are increasingly recognized for their potential as alternative indicators.

Purpose of the Study:

• To investigate the correlation between bacterial indicators and three groups of bacteriophages in wastewater and sludge.
• To evaluate the suitability of somatic coliphages (SOMCPH), F-RNA-specific phages (FRNAPH), and Bacteroides fragilis phages (BFRPH) as indicators of fecal pollution.
• To assess the persistence of these phages through wastewater treatment processes.

Main Methods:

• Monthly collection of raw and treated wastewater and sludge samples over two years from two treatment plants in Athens.
• Analysis of total coliforms, Escherichia coli, and intestinal enterococci as bacterial indicators.
• Quantification of SOMCPH, FRNAPH, and BFRPH populations in the collected samples.

Main Results:

• A clear correlation was observed between the counts of bacterial indicators and the presence of bacteriophages.
• Somatic coliphages (SOMCPH) were found in high densities.
• SOMCPH demonstrated significant resistance to the various wastewater treatment steps employed.

Conclusions:

• Bacteriophages, particularly SOMCPH, correlate well with established bacterial indicators of fecal pollution.
• SOMCPH are robust indicators, showing resistance to wastewater treatment, making them valuable for monitoring.
• The study supports the use of SOMCPH as supplementary indicators for assessing fecal contamination in water environments.