To evaluate the composition of the different liquid streams in a WWTP, information from literature was collected. The study focuses on the dissolved compounds that have the biggest influence on the ionic strength: SO4 2-, Na + , Cl -, PO4 3-, Mg 2+ , Ca 2+ , K + , VFA, NH4 + , HCO3 -. Values for pH were also collected since it is an important global parameter and it influences, for example, the ionic speciation. Single or multiple concentrations were gathered for all the elements studied, and 3 ranges (low, typical, high) were determined from the entire dataset.