WASTEWATER TREATMENT USING CONSTRUCTED WETLAND WITH WATER LETTUCE (EICHORNIA CRASIPIES)

A wetland was constructed in a laboratory-scale at the Department of Civil Engineering; Sree Chitra Tirunal College of Engineering which was established in April 1969 to demonstrate the gravel- based constructed wetland, using Water Lettuce. The experiment was carried out to demonstrate the enhanced removal efficiency for Water lettuce with constructed wetland in treating kitchen wastewater, from a nearby Campus restaurant. A retention period of ten days was chosen for the performance evaluation of the constructed wetland. Water Lettuce had improved the wastewater quality significantly as it had reduced 85.66% of Turbidity, BOD5 by 83.43%, No-3 by over 50%, 90% of SO-4, 46.2% of Cl- and Conductivity by 46.2% and Dissolve Oxygen by 58%. The pH increased by 23%, while the initial offensive odour of the raw water was reduced considerably. The effluent from the wet land was found useful in irrigation and keeping aquatic animals. However, it was noted that a 6- day detention time was found optimized for the treatment kitchen waste water. The the construction and maintenance cost involved was very minimal an so the treatment system was found to be more economical, as. The effluent was free from offensive odour and insect invasion.