A method for concentrating viruses recovered from sewage sludges

Area of Science:

• Environmental microbiology
• Virology
• Wastewater treatment

Background:

• Viruses in wastewater sludge are crucial indicators of fecal contamination and potential pathogens.
• Accurate enumeration of virions in sludge is essential for risk assessment and treatment efficacy monitoring.
• Existing methods for virion concentration can be labor-intensive and require significant resources.

Purpose of the Study:

• To evaluate and optimize the Katzenelson organic flocculation procedure for concentrating virions from digested sludge eluates.
• To determine the recovery efficiency of virions using the modified Katzenelson procedure.
• To assess the practicality and resource-saving potential of the method for routine laboratory use.

Main Methods:

• Buffered 10% beef extract eluates from primary, activated, and anaerobic digested sludges were prepared.
• Eluates were concentrated 20-fold using the Katzenelson organic flocculation procedure after diluting beef extract to 3%.
• Virion recovery was quantified by comparing numbers in concentrated samples to unconcentrated eluates.

Main Results:

• The weighted mean recovery of virions was approximately 58% of those in unconcentrated eluates.
• The Katzenelson procedure, when applied to diluted beef extract eluates, demonstrated variable flocculation quality.
• The method allows for a reduction in the number of cell cultures needed for virion assays.

Conclusions:

• The modified Katzenelson procedure offers a viable method for concentrating virions from digested sludges.
• While recovery rates are moderate, the procedure provides significant economies in laboratory resource utilization for virological analysis.
• Further optimization may be needed to address inconsistent flocculation for improved recovery rates.