Performance of laboratory-scale wetlands planted with tropical ornamental plants to treat domestic wastewater

This work proposes an innovative wastewater treatment system that consists of a constructed subsurface flow wetland planted with ornamental flowers of high market value. in addition to the benefit of the water treatment, this cash crop provides a profitable business-by producing commercial flowers that can meet all biological and safety requirements in order to be commercialized. This characteristic of the treatment system makes it very valuable for application in developing countries. Five different species of ornamental plants were studied from September 2004 to January 2005. Several water quality parameters were evaluated at the inlet and outlet of a laboratory-scale system. COD was reduced by more than 75% in all cases; BOD and nitrogen were removed by more than 70%, except in one cell; phosphorus was reduced by more than 66% and the dissolved oxygen increased from 0.175 to 5.8 mg L-1. Total and fecal. coliforms were removed in the wetland by more than 99.3%. According to these results, it is feasible to couple ornamental flower production with wastewater treatment. A pilot-scale study is recommended in order to validate the preliminary results under more realistic conditions.