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Degradation of 2,4‐Dichlorophenol by Combining Photo‐Assisted Fenton Reaction and Biological Treatment
Author(s) -
Momani F. Al,
Sans C.,
Contreras S.,
Esplugas S.
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 - 10.2175/106143006x111664
Subject(s) - chemistry , biodegradation , biochemical oxygen demand , activated sludge , 2,4 dichlorophenol , chemical oxygen demand , wastewater , hydrogen peroxide , total organic carbon , bioreactor , batch reactor , phenol , activated carbon , volatile suspended solids , pulp and paper industry , nuclear chemistry , environmental chemistry , catalysis , environmental engineering , organic chemistry , adsorption , environmental science , biology , bacteria , engineering , genetics
The photo‐Fenton reaction effect on the biodegradability improvement of 100 mg/L solution of 2,4‐dichlorophenol (DCP) has been investigated. Biochemical oxygen demand (BOD) at 5 and 21 days, BOD n /chemical oxygen demand (COD) and BOD n /total organic carbon (TOC) ratios, average oxidation state, and inhibition on activated sludge were monitored. For 50 mg/L hydrogen peroxide and 10 mg/L iron(II) initial concentrations and 40 minutes of reaction time in the photo‐Fenton process, the biodegradability of the pretreated solution, measured as BOD 5 /COD ratio, was improved from 0 for the original DCP solution up to 0.18 (BOD 21 /COD = 0.24). At that point, all DCP was eliminated from the solution. To study the effect of the pretreatment step, the biological oxidation of pretreated solutions was tested in two semicontinuous stirred tank reactors, one operated with activated sludge and one with biomass acclimated to phenol. Results showed that more than 80% TOC removal could be obtained by codigestion of the pretreated solution with municipal wastewater. Total organic carbon removals of approximately 60% were also obtained when the sole carbon source for the aerobic reactors was the pretreated solution. The hydraulic retention times used in the bioreactors were of the same order of magnitude as those used at domestic wastewater treatment plants (i.e., between 12 and 24 hours). Kinetic studies based on pseudo‐first‐order kinetics have also been carried out. Constants were found to be in range 0.67 to 1.7 L·g total volatiles suspended solids −1 ·h −1 .