LANDFILL LEACHATE DEGRADATION USING ZINC OXIDE UNDER DIRECT SUNLIGHT

There has been a significant increase in the generation of MSW (Municipal Solid Waste) in India over the last few decades. The degradation of persistent organic pollutant using advanced oxidation processes with sunlight as energy source have a great advantage at lower costs. Pallikaranai wetland is a freshwater marsh in the city of Chennai, India. Pallikaranai marshland is the only surviving wetland ecosystem of the city and is among the few and last remaining natural wetlands of South India. MSW generated in Pallikaranai, Chennai includes 80% of residential waste, 17% of commercial waste, 3% of institutional waste and 2% of industrial waste. The physical and chemical properties of the MSW generated in Chennai, showed that majority of waste composed of green waste (32.3%) and inert materials (34.7%) i.e. stones and glass. The overall aim of the work was to apply an innovative clean technology, namely photocatalytic oxidation, and demonstrate its efficiency in leachate treatment by using solar energy. The study of photo catalytic process was conducted for the removal of parameters like Colour, COD, BOD, alkalinity, turbidity, TDS, conductivity, hardness in leachate. To determine the optimum dosage of ZnO, effect of pH and contact time and to determine the removal efficiency of the pollutant. The solar photocatalytic treatment of leachate with zinc oxide (ZnO) as catalyst dosage of 0.2, 0.4, 0.6, 0.8, 1.0 and 1.2 g/500ml was conducted by maintaining pH 4, 5 and 6 of the leachate sample with exposure to sunlight in 5 h of time. The characteristics of leachate sample were monitored for every one hour of time period. It was observed that the maximum pollutant removal was occurred at the pH 5 of the leachate sample than in pH 4 and 6.