Treatment of municipal landfill leachate by catalytic wet air oxidation: Assessment of the role of operating parameters by factorial design

Journal Article · Mon Aug 15 00:00:00 EDT 2011 · Waste Management

DOI:https://doi.org/10.1016/j.wasman.2011.03.023· OSTI ID:21578454

Anglada, Angela; Urtiaga, Ane; Ortiz, Inmaculada ^[1]; Mantzavinos, Dionissios ^[2]; Diamadopoulos, Evan ^[2]

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1. Department of Chemical Engineering, University of Cantabria, Avenida de los Castros s/n, 39005 Santander, Cantabria (Spain)
2. Department of Environmental Engineering, Technical University of Crete, Polytechneioupolis, GR-73100 Chania (Greece)

Highlights: > Landfill leachates can be treated effectively by catalytic wet oxidation. > Addition of H{sub 2}O{sub 2} in the presence of transition metals promotes degradation. > Factorial design evaluates the statistically significant operating conditions. > H{sub 2}O{sub 2}, reaction time and temperature are critical in determining performance. - Abstract: The wet air oxidation (WAO) of municipal landfill leachate catalyzed by cupric ions and promoted by hydrogen peroxide was investigated. The effect of operating conditions such as WAO treatment time (15-30 min), temperature (160-200 deg. C), Cu{sup 2+} concentration (250-750 mg L{sup -1}) and H{sub 2}O{sub 2} concentration (0-1500 mg L{sup -1}) on chemical oxygen demand (COD) removal was investigated by factorial design considering a two-stage, sequential process comprising the heating-up of the reactor and the actual WAO. The leachate, at an initial COD of 4920 mg L{sup -1}, was acidified to pH 3 leading to 31% COD decrease presumably due to the coagulation/precipitation of colloidal and other organic matter. During the 45 min long heating-up period of the WAO reactor under an inert atmosphere, COD removal values up to 35% (based on the initial COD value) were recorded as a result of the catalytic decomposition of H{sub 2}O{sub 2} to reactive hydroxyl radicals. WAO at 2.5 MPa oxygen partial pressure advanced treatment further; for example, 22 min of oxidation at 200 deg. C, 250 mg L{sup -1} Cu{sup 2+} and 0-1500 mg L{sup -1} H{sub 2}O{sub 2} resulted in an overall (i.e. including acidification and heating-up) COD reduction of 78%. Amongst the operating variables in question, temperature had the strongest influence on both the heating-up and WAO stages, while H{sub 2}O{sub 2} concentration strongly affected the former and reaction time the latter. Nonetheless, the effects of temperature and H{sub 2}O{sub 2} concentration were found to depend on the concentration levels of catalyst as suggested by the significance of their 3rd order interaction term.

• OSTI ID: 21578454
• Journal Information: Waste Management, Vol. 31, Issue 8; Other Information: DOI: 10.1016/j.wasman.2011.03.023; PII: S0956-053X(11)00168-1; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0956-053X
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ACIDIFICATION
AIR
CATALYSTS
CHEMICAL OXYGEN DEMAND
COPPER
COPPER IONS
DECOMPOSITION
DESIGN
HEATING
HYDROGEN PEROXIDE
HYDROXYL RADICALS
INERT ATMOSPHERE
INTERACTIONS
LEACHATES
ORGANIC MATTER
OXIDATION
PARTIAL PRESSURE
PH VALUE
SANITARY LANDFILLS
ATMOSPHERES
CHARGED PARTICLES
CHEMICAL REACTIONS
CONTROLLED ATMOSPHERES
DISPERSIONS
ELEMENTS
FLUIDS
GASES
HOMOGENEOUS MIXTURES
HYDROGEN COMPOUNDS
IONS
MANAGEMENT
MATTER
METALS
MIXTURES
OXYGEN COMPOUNDS
PEROXIDES
PHYSICAL PROPERTIES
RADICALS
SOLUTIONS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS
WASTE DISPOSAL
WASTE MANAGEMENT