Removal of rotavirus and adenovirus from artificial ground water using hydrochar derived from sewage sludge

To determine the pathogenic virus removal performance of an adsorbent produced from hydrothermal carbonization of sewage sludge.

The removal of human pathogenic rotavirus and adenovirus was investigated with columns of 10 cm saturated sand with and without amendments of 1·5% (w/w) hydrochar. Virus concentrations were determined with reverse transcription (RT) quantitative polymerase chain reaction (qPCR). The experiments with sand showed 1 log removal, while the columns with 1·5% (w/w) hydrochar amendment showed 2 to >3 log removal for both viruses. Deionized (DI) water flushing into the virus-retaining columns revealed that the secondary energy minimum played a larger role in the attachment of rotavirus onto hydrochar surfaces than adenovirus. Improved virus removal may be attributed to the introduction of hydrophobic and/or meso-macro surface structures of the hydrochar providing favourable attachment sites for viruses.

Hydrochar amended sand beds showed improved virus removal efficiencies exceeding 99·6% corresponding to 2·4 log removal. The addition of humic acid in the influent did not hinder the adsorptive removal of viruses.

This study suggests that hydrochar derived from sewage sludge can be used as an adsorbent for virus removal in water treatment.