This report covers the results of the Clear Waters from Pharmaceuticals 2 (CWPharma 21) project continuing the work of the original CWPharma2 project which concluded in December 2020. Both projects were funded by the EU’s Interreg Baltic Sea Region Programme. CWPharma evaluated occurrence and routes of active pharmaceutical ingredients (APIs) in the water cycle and provided recommendations on technical and non-technical measures to reduce API loads entering the Baltic Sea. Recommendations for technical measures were published in the CWPharma ‘Guidelines for advanced API removal processes’ (Stapf et al., 2020), which also includes a modular approach to their successful implementation. The individual modules are: 1) WWTP fitness check, 2) feasibility study, 3) detailed planning, and 4) optimization of existing systems.

Within CWPharma 2, project partners from Denmark, Estonia, Finland, Germany, Latvia, and Poland continued the work of reducing API loads from the aforementioned countries into the Baltic Sea. The focus was to help wastewater treatment plant (WWTP) operators interested in reducing their API discharges to practically implement the four different modules of the guideline. This report summarizes the results of the first module ‘WWTP fitness check’ that have been carried out for about 80 WWTPs from eight Baltic Sea countries and aggregates the anonymized data from the WWTPs to present an overview of general as well as country-specific results, trends and considerations.