Have you been able to monitor the concentration of the SARS-CoV-2 in the wastewater at any of the test sites?

No, the results presented in Medema et al. (2020) show only data about the detection of SARS-CoV-2. Here, the plan was to have a reproducible method for concentrating the virus from sewage and the isolation RNA from the concentrate. However, RT-qPCR can indeed be used to quantify viruses. Therefore, future studies aim to improve the detection method for SARS-CoV-2, mainly for reasons of quantification.