Premium
Supercritical water oxidation of MSW leachate: Factor analysis and behavior of heavy metals
Author(s) -
Zou Daoan,
Chi Yong,
Dong Jun,
Fu Chao,
Ni Mingjiang
Publication year - 2014
Publication title -
environmental progress and sustainable energy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.495
H-Index - 66
eISSN - 1944-7450
pISSN - 1944-7442
DOI - 10.1002/ep.11891
Subject(s) - leachate , supercritical water oxidation , chemical oxygen demand , supercritical fluid , chemistry , incineration , municipal solid waste , environmental chemistry , metal , waste management , environmental engineering , wastewater , environmental science , organic chemistry , engineering
Generated from municipal solid waste (MSW) landfill sites and incineration plants, leachate may contain various contaminants such as ammonia, organic pollutants and heavy metals; thus it is difficult to be treated by conventional methods. In this work, supercritical water oxidation (SCWO) of leachate was conducted in a batch reactor based on orthogonal test. The effect of operation parameters on the destruction of organics and the removal of heavy metals was examined. Range and variance analysis revealed that, factors that affected chemical oxygen demand (COD) destruction, in descending order, are oxygen, temperature, reaction time and pressure; for ammonia nitrogen (NH 4 ‐N), the order was temperature, oxygen, reaction time and pressure. It was proven that pressure at supercritical region had limited influence on oxidation reaction. Destruction efficiencies of COD and NH 4 ‐N increased significantly with rising temperature and oxidant amount, with a maximum value of 98.5 and 76.2% for COD and NH 4 ‐N, respectively. Besides, a large proportion of heavy metals in original leachate precipitated into solid ash. Energy dispersive spectroscopy analysis indicated that the main component of solid product was calcium carbonate; metal elements accounted for 35 wt % of the ash. Furthermore, submicron crystalline hydroxyl‐Fe oxide detected by X‐ray diffraction spectra was considered to be formed through complicated process including decomposition and oxidation. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 1117–1124, 2014