Ibuprofen and caffeine removal in vertical flow and free-floating macrophyte constructed wetlands with Heliconia rostrata and Eichornia crassipes

Abstract

Abstract Emerging pollutants appear more frequently in the environment and adverse effects affects not only human health but also the environment. This study evaluated the efficiency of two types of constructed wetlands (CWs) and a 12-unit mesocosm-scale system to remove ibuprofen and caffeine compounds: (i) vertical flow constructed wetland (VF-CW) planted with Heliconia rostrata using sand as filter media with and without earthworms; (ii) free-floating surface horizontal flow constructed wetland with Eichhornia crassipes macrophyte (FFM-CW); and (iii) mesocosm-scale 12 unit system using Eichhornia crassipes with clean water (opposed to wastewater), where the intention was to evaluate the removal of the added compounds without effects from wastewater or biofilm. The systems were efficient in removing the pollutants and demonstrated a limit for the applied COD and BOD rates, where the adequate application rate was 120\u202fg COD.m−2.d−1 and 70\u202fg BOD.m−2.d−1 to obtain maximum removal efficiency. TP varied independent of the applied load, while TN and NH4+ showed removals (99%) close to the applied rates (9\u202fg TN.m−2.d−1 and 7\u202fg NH4+.m−2.d−1 for the VF-CW and 8.5\u202fg TN.m−2.d−1 and 5\u202fg NH4+.m−2.d−1 for the FFM-CW). The emerging contaminants removal efficiency in the VF-CW was 97 and 89% for caffeine and ibuprofen, respectively. Inserting earthworms did not show a significant variation in relation to compound removal. The FFM-CW system removed 94 and 89% of the caffeine and ibuprofen, respectively. The VF-CW system with filter media presented better removal for caffeine and ibuprofen when compared to the FFM-CW. The performance between the macrophyte E. crassipes systems in the mesocosm units showed potential to remove emerging compounds even though clean water was used, with a 70% removal efficiency for caffeine and ibuprofen.