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Oxidative degradation of lurgi coal gasification wastewater: Optimization using response surface methodology
Author(s) -
Wang Yuzhen,
Wang Shuzhong,
Guo Yang,
Xu Donghai,
Gong Yanmeng,
Tang Xingying,
Zhang Jie
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.11927
Subject(s) - effluent , wastewater , response surface methodology , chemistry , degradation (telecommunications) , pollutant , coal , central composite design , chemical oxygen demand , environmental chemistry , total organic carbon , nitrogen , pulp and paper industry , environmental science , environmental engineering , chromatography , organic chemistry , telecommunications , computer science , engineering
Lurgi coal‐gasification wastewater with an initial total organic carbon (TOC) of 5000 mg/L and ammonia nitrogen (NH 3 N) of 1500 mg/L was treated by supercritical water oxidation technology to make the effluent reach the national wastewater discharge standard I in China (TOC < 20 mg/L, NH 3 N < 15 mg/L). Response surface methodology method combined with central composite design and regression analysis were used to statistically analyze and optimize the operating parameters. The effect degree of the parameters on TOC and NH 3 N decreasing were in the following order: temperature (440–600°C) > oxygen ratio (OR) (1–5) > reaction time (20–300 s) > pressure (22.2–30.2 MPa). The interactive effects of temperature and OR were significant on both COD and NH 3 N decreasing. The optimum conditions within experimental ranges were: 540°C, 27 MPa, OR of 3, and reaction time of 219 s. Under these conditions, the experimental TOC and NH 3 N decreasing efficiencies were 99.69 and 99.07%, respectively. The effluent can reach the wastewater discharge standard I. The main intermediate products of the pollutants during the oxidation process were detected and possible degradation pathways were also proposed. © 2014 American Institute of Chemical Engineers Environ Prog, 33: 1258–1265, 2014