An aquatic macrophyte-based wastewater treatment study was carried out to investigate
the nutrient removal efficiency of Colocasia esculenta, a common semi-aquatic macrophyte.
Domestic sewage was used as the wastewater in this study. Apart from the removal of
nutrients, the stabilisation of the organic matter present in thewastewaterwas also assessed
in terms ofCODremoval. The plantswere cultured in shallowraceways supported by a gravel
bed substratum and thewastewaterwas allowed to flowthrough the raceways continuously
in subsurface flow (SSF) mode. This experiment was conducted for 20 days with a change
of wastewater every 20th day initially and every 5th day at a later stage of the experiment.
Control raceways without plants were also operated.
The results of the study revealed that the subsurface flowsystems planted with C. esculenta
could decrease the nitrate and phosphate content of thewastewater, besides organic matter.
The quality of treated water from the raceways with plants was better than those without
plants. Also C. esculenta was found to resist COD concentration as high as 1650mgl−1.