Abstrait

Wastewater Treatment: An Ecological Sanitation Approach in a Constructed Wetland

Jaya S.Pillai, Vijayan N.

This study investigates the potential of constructed wetlands to function as Ecological Sanitation systems, achieving water reuse, nutrient reuse and biomass production. Vertical flow constructed wetland systems planted with indigenous species such as Napier Bajra Hybrid grass (Pennisetum purpureum x Pennisetum typhoides) and Guinea grass (Panicum maximum) were developed for the treatment and utilization of Greywater for non-potable purposes. The performance of the control and experimental systems were analysed and compared based on water quality parameters such as Turbidity, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Nitrates, Phosphates, and Total Nitrogen (TN). The study also estimated and compared the above ground biomass yield from the constructed wetland systems. For all the water quality parameters analysed during the study period, the vertical flow constructed wetland system planted with Napier Bajra Hybrid grass achieved high removal efficiency. Best removal efficiencies observed were: Turbidity (99%), TSS (93%), BOD (94%), COD (82%), Nitrates (88%), Phosphates (63%) and TN (60%). The final effluent concentration of the parameters tested reached the standards required for non-potable purposes as per the USEPA guidelines for water reuse. The annual above ground biomass yield (from 6-8 harvests) of Napier Bajra Hybrid grass was found to be higher (200 -250 t/ha) when compared to Guinea grass (60-72 t/ha). Based on the results, the constructed wetland system planted with Napier Bajra Hybrid grass proved to be a reliable, onsite and decentralised Ecological Sanitation system.