Feasibility of using divergent plantation to aggrandize the pollutants abatement from sewage and biomass production in treatment wetlands

Constructed wetlands are one of the most viable wastewater treatment technologies, with an additional aspect of biomass production that could be utilized in the manufacturing of valuable products. With this objective, four species of divergent commercial plants were grown individually and polyculture in horizontal subsurface flow constructed wetlands (HSFCW). Rural sewage was supplied from a storage tank to each CW through the inlet chamber. The experiment was continued for 12 weeks (July to October). Collectively, the HSFCW having polyculture of plants was more effective in the removal of all pollutants. While monoculture of Ipomoea aquatica exhibited better performance for the reduction of chemical oxygen demand (COD) and nutrients, viz., total nitrogen (TN), total phosphorus (TP), ammonium nitrogen (NH4+–N), and nitrate-nitrogen (NO3–N) with a removal efficiency of 69, 77, 96, 90 and 80%, respectively. Whereas, Iris pseudacorus and Canna indica showed significantly better results for fecal coliform and total suspended solids reduction. At the last stage of the experiment, all plant species achieved the maximum growth rate; particularly, Ipomoea aquatica and polyculture or mixed planting (MP) had the highest growth rate and larger above-ground biomass. Thus, current findings reflect that MP wetland in wastewater treatment coupled with biomass production renders environmental and economic benefits.