Fate of priority pharmaceuticals and their main metabolites and transformation products in microalgae-based wastewater treatment systems

•High rate algae ponds removed efficiently most of the target pharmaceuticals.•Primary treatment did not influence the removal capacity of the HRAP systems.•Positive removals for non-biodegradable compounds were achieved.•Venlafaxine or O-desmethylvenlafaxine, usually recalcintrant in CAS, were removed.•Biomass samples were analised to perform a mass balance of the HRAP system.