The meat processing industry generates a large amount of wastewater which represents a serious problem due to their high levels of organic matter which demands effective and high cost treatments. In the present study the effectiveness of the wastewater treatment by dissolved air flotation (DAF) followed by advanced oxidation processes (AOPs) using photo-peroxidation (H2O2/UV) and photo-Fenton reactions were evaluated in laboratory scale. The primary treatment was carried out in a DAF system, using optimal dosages of ferric sulfate and coagulation aids. The efficiency of these processes was evaluated through the following parameters: COD, BOD5, color, turbidity, total solids, fixed solids and volatile solids, both before and after the DAF and AOP treatments. The elimination efficiency of pollutants was monitored by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) analysis. The results had shown that the DAF treatment efficiently reduced the COD, color, turbidity and total solids contents. in addition, the advanced oxidation process increased the organic matter removal of the treated samples. Among the AOPs, the photo-Fenton reaction reached the best over-all results. These results show that the DAF process followed by an ACIP process might be efficient for meat wastewater treatment, intended or not to water reuse purposes. (C) 2009 Elsevier B.V. All rights reserved.