Are there details about the treatment process of WWTPs in the sampled locations from Medema et al., 2020?

Details on processes applied at the different WWTPs can be requested at the respective water authorities. in general, most of the WWTPs in The Netherlands apply primary treatment (removal of solids) and secondary (biological) treatment: (typically [aerobic] active sludge) for removal of organic carbon, usually followed by tertiary treatment processes (nutrient removal) and incidentally quaternary processes for removal of organic micropollutants.