title: An innovative multistage treatment system for sanitary landfill leachate depuration: Studies at pilot-scale.
abstract: In this work, an innovative methodology for the treatment of landfill leachates, after aerobic lagooning, is proposed and adjusted at pilot-scale. This methodology involves an aerobic activated sludge biological pre-oxidation (ASBO), a coagulation/sedimentation step (240mgFe3+/L, at pH4.2) and a photo-oxidation through a photo-Fenton (PF) reaction (60mg Fe2+, at pH2.8) combining solar and artificial light. The ASBO process applied to a leachate after aerobic lagooning, with high organic and nitrogen content (1.1-1.5gC/L; 0.8-3.0gN/L) and low biodegradability (BOD5/COD =0.07-0.13), is capable to oxidise 62-99% of the ammonium nitrogen, consuming only the affluent alkalinity (70-100%). The coagulation/sedimentation stage led to the humic acids precipitation, promoting a marked change in leachate colour, from dark-brown to yellowish-brown (related to fulvic acids), accompanied by a reduction of 60%, 58% and 88% on DOC, COD and TSS, respectively. The PF system promoted the degradation of the recalcitrant organic molecules into more easily biodegradable ones. According to Zahn-Wellens biodegradability test, a leachate with 419mg DOC/L after coagulation, would have to be photo-oxidized until DOC <256mg/L, consuming 117mM of H2O2and 10.4kJ/L of accumulated UV energy, to achieve an effluent that can be biologically treated in compliance with the COD discharge limit (150mg O2/L) into water bodies. The biological process downstream from the photocatalytic system would promote a mineralization >60%. The PF step cost to treat 100m3/day of leachate was 6.41€/m3, combining 1339m2of CPCs with 31 lamps.
authors: Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. Electronic address: tania.silva@fe.up.pt.
authors: Tânia F C V
authors: TFCV
authors: Silva
authors: Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
authors: Petrick A
authors: PA
authors: Soares
authors: Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
authors: Diego R
authors: DR
authors: Manenti
authors: Efacec Engenharia e Sistemas S.A. (Unidade de Negócios Ambiente), SA, Rua Eng. Frederico Ulrich - Guardeiras, Apartado 3003, 4471-907 Moreira da Maia, Portugal.
authors: Amélia
authors: A
authors: Fonseca
authors: Efacec Engenharia e Sistemas S.A. (Unidade de Negócios Ambiente), SA, Rua Eng. Frederico Ulrich - Guardeiras, Apartado 3003, 4471-907 Moreira da Maia, Portugal.
authors: Isabel
authors: I
authors: Saraiva
authors: Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
authors: Rui A R
authors: RAR
authors: Boaventura
authors: Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. Electronic address: vilar@fe.up.pt.
authors: Vítor J P
authors: VJP
authors: Vilar
keywords: Biological nitrification; Coagulation/sedimentation; Mature sanitary landfill leachate; Photo-Fenton; Solar/artificial light