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Enhanced Biodegradation of Azo Dyes Using an Integrated Elemental Iron‐Activated Sludge System: II. Effects of Physical–Chemical Parameters
Author(s) -
Saxe Jennie Perey,
Lubenow Brian L.,
Chiu Pei C.,
Huang ChinPao,
Cha Daniel K.
Publication year - 2006
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143005x84486
Subject(s) - chemistry , phosphate , biodegradation , sulfate , zerovalent iron , activated sludge , chloride , wastewater , orange (colour) , nuclear chemistry , reaction rate constant , chromatography , inorganic chemistry , kinetics , adsorption , environmental engineering , organic chemistry , engineering , food science , physics , quantum mechanics
As part of a study to evaluate an integrated zero‐valent iron (Fe 0 )‐biological oxidation process for treating azo dye wastewaters, we conducted batch and column experiments with the azo dye orange G to assess the effects of solution conditions on the performance of iron pretreatment. The influence of iron type and surface area, solution pH, dissolved inorganic salts, and phosphate ion on the reduction (decolorization) of orange G solution were examined. In batch experiments, increased iron surface area, decreased pH, and chloride and sulfate salts enhanced dye decolorization, whereas high pH (9.9) and phosphate concentrations (>3 mg/L PO 4 ‐P) inhibited dye reduction. Results from batch experiments were confirmed in column experiments. An increase in temperature from 22 to 35°C resulted in a near doubling of the reduction rate constant in a column study. The abiotic reduction results illustrate the feasibility and potential limitations of an integrated iron column, activated sludge treatment process for wastewaters containing azo dyes.