Use of vinasse and coffee waste as chelating agent of photo-Fenton landfill leachate treatment

Use of copper sheet in a solar photo-Fenton-like process applied in the treatment of landfill leachate

It is known that copper can be used as catalyst in photo-Fenton-like process; however, there is a lack of information related with its use in the treatment of landfill leachate (LL) in solar photo-Fenton-like processes. Here, we studied the effect of the mass of a copper sheet, the pH of the solution, and the concentration of LL in the removal of the organic matter present in this water. Before the reaction with landfill leachate, the copper sheet used in the reaction was constituted by Cu⁺ and Cu₂O, respectively. The results showed that in a volume of 0.5 L of a pretreated LL, the higher removal of organic matter resulted using a mass of 2.7 g of the copper sheet, a pH of solution of 5, and a concentration of LL of a 10%, obtaining a final value of C/C₀ of chemical oxygen demand (COD) of 0.34, 0.54, 0.66, and 0.84 for concentrations of 25%, 50%, 75%, and 100%, respectively, and 0.0041, 0.0042, 0.0043, and 0.016 for concentration of 25%, 50%, 75%, and 100%, respectively, of C/C₀ of humic acids. The photolysis on LL at its natural pH using solar UV removes very little humic acid and COD, going from 9.4 to 8.5 and 7.7 Abs₂₅₄ for photolysis and UV + H₂O₂, obtaining 8.6 and 17.6% of removal, respectively, and 2.01 and 13.04% removal of COD, respectively. Copper sheet applied under Fenton-like conditions results in 65.9% removal and an increase of 0.2% for humic acid and COD, respectively. Removal using only H₂O₂ for Abs₂₅₄ and COD was 11.95 and 4.3%, respectively. Raw LL produced a 29.1% inhibition of the biological activated sludge rate after the adjustment to pH 7 and the final process of inhibition was 0.23%.