Use of sawdust as pretreatment of photo-Fenton process in the depuration of landfill leachate

Abstract

A research of the depuration of landfill leachate using sawdust as activated carbon material to be applied in adsorption process as pretreatment of solar photo-Fenton and solar photo-Fenton + O₃, was carried out. The activated sawdust shows very irregular shapes and pores, and a high capacity to remove ammonium (87.0%), iron (70.2%) and copper (61.1%). As well, it has the capacity to remove humic acid (18.3%), COD (33.7%) and colour (19.5%). Also, a removal of organic matter was obtained in terms of COD (76.4%), colour (74.9%), nitrate (50.0%), ammonium (12.8%) and humic acid (73.3%) due to the joint action of ozone and solar photo-Fenton process. The overall treatment (filtration, adsorption, photo-Fenton and photo-Fenton + ozone) carried out showed a very high removal of pollutants, with a reduction of COD, colour, ammonium and humic acid of 95.1%, 95.0%, 94.5% and 97.9%, respectively. With this enhancement in the landfill leachate (LL) quality, there is a reduction of toxicity, obtaining with the LL 50% diluted, a germination index for Lactuca sativa of 20% GI. This shows that the incorporation of sawdust is a useful pretreatment of photo-Fenton in the treatment of landfill leachate.

Keywords: Landfill leachate; Photo-Fenton; Sawdust.