Optimization of photocatalytic post-treatment of composting leachate using UV/TiO2

In this study, optimization of photocatalytic process via UV light and TiO2 nanoparticles immobilized on concrete surface in post-treatment of composting leachate was investigated. This investigation was conducted in laboratory scale and batch mode. Biological pretreated leachate samples were collected from the effluent of Gorgan composting leachate treatment facility in the north of Iran. Optimization of the simultaneous COD and color removal were carried out through experiments designed by response surface method and central composite design with six replications in central point. Based on the results of experiments, after 21.5 h of radiation with 7.5mWCm(-2) light intensity in pH 5.7 and in the presence of 48.8gm(-2) immobilized TiO2, maximum simultaneous COD and color removal were achieved to be 58 and 36%, respectively. GC/MS analysis revealed that the composting leachate contained various groups of refractory organic compounds, most of which could be degraded into simpler and more biodegradable by products, using photocatalytic process.