High performance concentration method for viruses in drinking water

According to the risk assessment of the WHO, highly infectious pathogenic viruses like rotaviruses should not be present in large-volume drinking water samples of up to 90m³. On the other hand, quantification methods for viruses are only operable in small volumes, and presently no concentration procedure for processing such large volumes has been reported. Therefore, the aim of this study was to demonstrate a procedure for processing viruses in-line of a drinking water pipeline by ultrafiltration (UF) and consecutive further concentration by monolithic filtration (MF) and centrifugal ultrafiltration (CeUF) of viruses to a final 1-mL sample. For testing this concept, the model virus bacteriophage MS2 was spiked continuously in UF instrumentation. Tap water was processed in volumes between 32.4m³ (22h) and 97.7m³ (72h) continuously either in dead-end (DE) or cross-flow (CF) mode. Best results were found by DE-UF over 22h. The concentration of MS2 was increased from 4.2×10⁴GU/mL (genomic units per milliliter) to 3.2×10¹⁰GU/mL and from 71PFU/mL to 2×10⁸PFU/mL as determined by qRT-PCR and plaque assay, respectively.