Effectiveness of Scirpus grossus in Treatment of Domestic Wastes in a Constructed Wetland

ABSTRACT

We examined the ability of Scirpus grossus planted in a constructed wetland to treat domestic wastewater. One unit was planted with S. grossus, and another unit was used as a control. Influent wastewater and effluent from each wetland were tested monthly for 10 physical, chemical, and biological parameters from May 2004 to July 2005. Better performance was obtained by the vegetated unit than by the control unit. Mean removal efficiencies observed with S. grossus were total suspended solids, 61%; NH₄ ⁺-N, 71%; NO₃ ⁻-N, 31%; total phosphorus 18%; fecal coliforms, 90%; and five-day biochemical oxygen demand, 69%. Plant growth was continuously monitored, and the above-ground biomass of S. grossus was harvested after eight months, 11 months, and 14 months, when plants reached their maximum shoot height and inflorescence formation started. S. grossus has great potential to remove pollutants in constructed wetlands in tropical regions, especially because above-ground harvesting would be a feasible plant management option by which nutrients could be subsequently removed.