Phytoremediation of domestic sewage using a floating wetland and assessing the pollutant removal effectiveness of four terrestrial plant species

Abstract

Several developing countries have limited infrastructure and finance to treat domestic and industrial wastewater. Discharging untreated sewage pollutes the surface and groundwater. Floating wetlands are an alternate method for treating polluted surface water bodies. This study's objective is to investigate the remediation of domestic wastewater using natural buoyant bamboo as a floating raft and terrestrial plants such as Ocimum tenuiflorum, Hibiscus, Chrysopogon zizanioides, and Canna in the floating wetland treatment (FWT) system. Floating rafts with a healthy terrestrial plant were planted and made to float in four plastic tanks with domestic wastewater. The water quality analysis was carried out periodically after 0, 3, 5, 10, 15, 20, and 25 days intervals. The experimental results of FWT using C. indica showed the highest removal efficiency of the pollutants such as TSS (96%), TP (98%), ammonia (95%), and DO (45%). In contrast, Ch. zizanioides showed its maximum removal efficiencies for turbidity (90%), TDS (48%), TN (85%), sodium (53%), potassium (74%), TP (92%), EC (27%), COD (93%), BOD (95%), and E. coli (47%). This study finding showed that the best terrestrial plants for removing various nutrients and other contaminants from municipal sewage were C. indica and Ch. zizanioides. However, further research is required to utilize these terrestrial plants with substrates under long-term study.