title: Hybrid zero valent iron (ZVI)/H2O2oxidation process for landfill leachate treatment with novel nanosize metallic calcium/iron composite.
abstract: A novel nanosize metallic calcium/iron dispersed reagent was synthesized and tested as coagulant/catalyst in a hybrid zero valent iron (ZVI)/H2O2oxidation process to treat leachate. Two different types of leachates, one from municipal solid waste (MSW) tipping hall (MSWIL) and second from an MSW landfill site (MSWLL), were collected and characterized. The morphology, elemental composition, and mineral phases of the nano-Ca/CaO and nano-Fe/Ca/CaO were characterized by scanning electron microscopy-electron dispersive spectroscopy (SEM-EDS) and x-ray powder diffraction (XRD) analysis. The coagulation process with 2.5 g L-1nano-Ca/CaO attained 64.0, 56.0, and 20.7% removal of color, chemical oxygen demand (COD), and total suspended solids (TSS) in MSWLL. With only 1.0 g L-1of nano-Fe/Ca/CaO, relatively high color, COD and TSS removal was achieved in MSWLL at 67.5, 60.2, and 37.7%, respectively. The heavy metal removal efficiency reached 91-99% after treatment with nano-Fe/Ca/CaO in both leachate samples. The coupling process, using 1.0 g L-1of nano-Fe/Ca/CaO and 20 mM H2O2doses, achieved enhancement removal of color, COD, and TSS, up to 95%, 96%, and 66%, respectively, without initial pH control. After this treatment, the color, COD, TSS, and heavy metals were significantly decreased, fitting the Korean discharge regulation limit. A hybrid coupled zero valent iron (ZVI)/H2O2oxidation process with novel nanosized metallic calcium/iron dispersed reagent proved to be a suitable treatment for dealing with leachate samples.
  
  
  
  Conventional treatments (biological or physicochemical) are not sufficient anymore to reach the level of purification needed to fully reduce the negative impact of landfill leachates on the environment. This implies that new treatment alternatives species must be proposed. A coupled zero valent iron (ZVI)/H2O2oxidation process proved to be a suitable treatment for dealing with leachate samples. Coagulation with nFe/Ca/CaO allows 91-99% of heavy metals removal. The coupled coagulation-oxidation process by nFe/Ca/CaO reveals excellent ability to treat leachate. After coupled treatment the color, COD, and TSS were also much lower than the discharge regulation limit.
authors: a Department of Civil and Environmental Engineering , University of Ulsan , Ulsan , Republic of Korea.
authors: Son Dong
authors: SD
authors: Lee
authors: a Department of Civil and Environmental Engineering , University of Ulsan , Ulsan , Republic of Korea.
authors: Srinivasa Reddy
authors: SR
authors: Mallampati
authors: a Department of Civil and Environmental Engineering , University of Ulsan , Ulsan , Republic of Korea.
authors: Byoung Ho
authors: BH
authors: Lee
mesh_terms: D057919:Biological Oxygen Demand Analysis; D002118:Calcium / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D019216:Metals, Heavy / Q000032:analysis; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry; D062611:Solid Waste; D018505:Waste Management / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry; D014877:Water Pollution, Chemical / Q000517:prevention & control*
chemical_list: D017610:Calcium Compounds; D019216:Metals, Heavy; D010087:Oxides; D062611:Solid Waste; D014874:Water Pollutants, Chemical; D006861:Hydrogen Peroxide; C016538:lime; D007501:Iron; D002118:Calcium