Simultaneous removal of ibuprofen, organic material, and nutrients from domestic wastewater through a pilot-scale vertical sub-surface flow constructed wetland with aeration system

Abstract

Pharmaceutical compounds in wastewater are currently becoming emerging concern as the utilization of drugs in anthropogenic activities. This research analyzed the effectiveness of pilot-scale vertical subsurface flow constructed wetland (VSSFCW) planted with Scirpus grossus using an aeration system for simultaneous removal of ibuprofen, chemical oxygen demand (COD) and nutrients (NH3-N, NO3-N, and PO4-P) from domestic wastewater. The constructed wetland (CW) platforms (500 L capacity) filled with gravel and sand and planted with native species of S. grossus were used to treat pharmaceutical content in domestic wastewater continuously for 21 days. Three experiments were performed with hydraulic retention time (HRT) of 3, 4 and 5 days. Aeration rates of 0, 1, and 2 L/min were employed for each HRT. The combined effect of HRT, exposure period, and aeration to simultaneously remove ibuprofen, organic materials, and nutrients were examined statistically using Two-way ANOVA and Tukey HSD test. Filtration and adsorption mechanisms of ibuprofen compound by sand medium matrix were proven to occur using solid phase extraction method. The removal efficiency of ibuprofen and COD were dependent on the applied aeration and HRT (p < 0.05). A longer HRT increased the removal efficiency of ibuprofen, while it did not significantly affect the nutrient removal (p ≥ 0.05). The VSSFCW under 2 L/min aeration and HRT of 5 days has removed 99.3% of ibuprofen, 88.2% of COD, 99.1% of ammonia, 72.9% of nitrate-nitrogen, and 83.2% of orthophosphate with effluent successfully met the effluent Standard B set by Malaysian Government. Therefore, the VSSFCW planted with S. grossus becomes a technically feasible method for treating sewage containing pharmaceutical compounds.