Optimum dilution for Phytoremediation of distillery effluent in constructed wet lands

Effluent ‘Coda’ originating from palmyrah toddy distillery units is the major source of environmental pollution in the Jaffna district of Sri Lanka. Spent wash produced from distilleries is rich in organic material and characteristically less toxic. A research was carried out to find the optimal dilution factor of the effluent before discharge through construction of wet lands which is a new, ecofriendly, economically viable and environmentally safe strategy to manage the distillery effluent. The effluent was diluted as 5, 4, 3, 2, and 1 times with ground water. Complete failures of first series of dilution, treatments were discarded and new effluent was further diluted 5, 10 and 20 times to facilitate the optimum plant growth. The results revealed that aquatic plants, Eichhormia sp, Lemna sp, Pistia sp and Lemna minor were used successfully to treat the spent wash, after aeration, pH adjustment, and dilution. It was found that dilution factor 5. The water samples were collected from inlets and outlets of constructed and analyzed for EC, PO43-, and NO3-. The removal rates of PO43in constructed wetland were 48.24%, 25.88%, and 51.76%,, Eichhormia sp, Lemna and Lemna minor respectively. It was found constructed wetland shows higher removal efficiency of NO3-. The 35.63%, 42.53%,55.17% removal rates of NO3were obtained by Eichhormia sp, Lemna sp, Pistia sp and Lemna minor. It could be use the spent wash as a liquid fertilizer for cultivating field through, construction of wetlands.