We have recently published our work on the evaluation of a virus concentration method based on ultrafiltration and wet foam elution for studying viruses from large-volume water samples as a open acces paper:
Organized by the International Water Association
https://iwa-network.org/learn/covid-19-wastewater-based-epidemiology/
More info at: https://iwa-network.org/news/iwa-webinar-covid-19-wastewater-based-epidemiology/