Landfill leachate treatment using combined fish scales based activated carbon and solar advanced oxidation processes

The depuration of landfill leachate (LL) was evaluated by solar advanced oxidation processes (AOPs) (photo-Fenton + O-3 and photo-Fenton +O-2) and adsorption processes, using activated carbon made from fish scales, as either post-treatment or pre-treatment of advanced oxidation process. Also, the effect in the reduction of toxicity of LL depurated under these methods was evaluated. The activated carbon Brunauer-Emmett-Teller (BET) surface area is 1.8329 m(2)/g and the adsorption average pore width is 12.79833 nm, considered as a mesoporous material. When AOPs were used as treatment and adsorption was used as post-treatment of the LL, a removal of 67%, 98%, 98.9%, 83.3% and 99.6% of chemical oxygen demand (COD), colour, copper, iron and ABS(254), respectively, was obtained. When the adsorption process was applied as AOP pre-treatment, the removal of organic matter was better in comparison to the results of the adsorption process as AOPs post-treatment. This resulted in a removal of COD, colour, copper, iron and ABS(254) of 75.4%, 99.4%, 94.4%, 68.3% and 98.1%, respectively. When the AOPs were followed the adsorption process, a germination index (GI) of 126%, 122% and 116% was obtained. This was higher than the results obtained by LL treated with PF+ O-2 in a solution concentration of 1%, 3% and 10%, respectively. When PF + 03 was used at a concentration solution of 1%, 3% and 10%, similar GI values were obtained (122%, 113% and 114%, respectively). The EC50 is very low for raw LL, but this value increases as the LL is treated. A very high EC50 is obtained for the adsorption process and for AOPs following the adsorption process, going from 1.8 to 21.0 V/V. Adsorption as pre-treatment helps removing colour and metals from LL, thus enhancing the performance of solar AOPs. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.