Performance of constructed wetland technology in removal of conventional pollutants from wastewater contaminated with ibuprofen
Teo, Malcolm Eng Hui.
Date of Issue2013
School of Civil and Environmental Engineering
Maritime Research Centre
Constructed Wetland (CW) technology has been proven to be very useful for the removal of conventional pollutant in, such as Chemical Oxygen Demands (COD), Ammonium (NH4+), and Total Phosphate (TP) from various kinds of wastewaters, and has been an up and rising topic in recent times. However, a rising concern in the treatment of wastewater using constructed wetlands is the occurrence of pharmaceutical product, which are regarded as emerging pollutants in wastewater treatment, posing potential threats to water environment, human health and also possibly bringing adverse effects on the performance of CWs due to its bioremediation characteristic. In this study, the pharmaceutical contaminant of concern is the common anti-inflammatory drug, Ibuprofen (IBP). The performance of a mesocosm-scale horizontal subsurface flow constructed wetland (HSSF-CW) in the treatment of conventional pollutants from the synthesised domestic wastewater is studied to evaluate the influences of IBP at 100µg/l injection into the influent wastewater. Typha spp. is used as the wetland plant of choice to study its influences on the wetland performance and survivability. A control wetland without vegetation is constructed for comparison, treating the same influent wastewater. It is found that the CW performance in treating COD is similar with plants or without, with a removal efficiency of approximately 85%. Significant disparity is observed in the removal efficiencies of ammonium and TP. The planted CW has an average efficiency of 82.8% for NH4+-N and 69.4% for TP, whereas the bare CW has an average efficiency of 45.4% and 12.6% for NH4+-N and TP respectively. The increased efficiency in the planted CW could be attributed to the active influences of Typha spp. which can decrease the negative effects IBP on the microbial communities in the wetland. Typha spp. has exhibited strong adaptability under the local tropical climate and even under the presence of significant level of pharmaceutical pollutant (IBP) in influent wastewater. In fact, it has been shown that the HSSF-CW system has a good performance to treat wastewater contaminated by IBP with the drastic increase in dosage as compared to other reports using 25µg/l of IBP. Further analysis of the results also suggests that the CW of such scale would require an adaptation of approximately 28 days under such tropical and influent wastewater conditions before achieving a stable and desirable performance.
Final Year Project (FYP)
Nanyang Technological University