Australian Journal of Basic and Applied Sciences, 3(2): 1087-1095, 2009 ISSN 1991-8178 Corresponding Author: Khadega I.A. Soil, Water and Environment Research Institute, Agricultural Research Center, Giza, Egypt.Phone: 202 33887729. E-Mail: Gabbrykhadega@yahoo.com 1087 Phenolic Compounds and COD Removal from Olive Mill Wastewater by Chemical and Biological Procedures Afify, A.S, Mahmoud, M.A., Emara, H.A. and Abdelkreem, Khadega I. 1 1 2 2 Department Biochemistry, Faculty of Agriculture, Cairo University, Egypt. 1 Soil, Water and Environment Research Institute, Agricultural Research Center, Giza, Egypt. 2 Abstract: In this study biological and chemical treatments were applied to olive mill wastewater (OMW) to reduce its phenolic compounds and chemical oxygen demand (COD) contents in order to reduce its toxicity. The biological treatment was carried out by using two fungal isolates ( Aspergillus wentii and Aspergillus niger) isolated from the OMW and compared with Pleurotus ostreatus. A. wentii was more efficient than A. niger and Pleurotus ostreatus in removing of COD and phenolic compounds from OMW. The optimum OMW dilution was 10%, in which the maximum COD removal (62.2%) and maximum phenolic compounds reduction (80.9%) were obtained by A. wentii. This was followed by 59.3% removal of COD and 79.6% reduction of phenolic compounds obtained by P. ostreatus at the same OMW dilution (10%). Lower biodegradation percentages of COD (28% at 40% OMW dilution) and phenolic compounds reduction (72.9% at 30% OMW dilution) were obtained by A. niger. Different chemical treatments were applied primary on tannic acid solution to select the best 2 2 of them for OMW application. These treatments were UV alone and combined with H O , Diefferent Fenton systyems and photocatalysis by titanium dioxide. The maximum degradation of tannic acid 2 2 obtained in the first treatment was 47% at H O concentration 0.11M at pH 9 under UV radiation. The maximum tannic acid degradation obtained by Fenton system was 70%. It was obtained at both Fe 2+ 2 2 concentrations (0.0024M and 0.0048M) and 0.11M H O in dark and UV radiation at pH 9. While 2 the maximum degradation obtained by photocatalysis by titanium dioxide was 35% at TiO 50mg/l and pH 5. The maximum degradation of phenolic compounds (74.4%) was obtained when OMW 2 2 treated with 0.55M of H O in dark after 40 min . 2 Key word: Olive mill wastewater; Fenton; Photo-Fenton; UV plus hydrogen peroxide and TiO INTRODUCTION Olive mill wastewater (OMW) composed of many complex substances that are not easily degradable. The acid pH and the high amounts of organic matter and phenols make it very difficult to be purified. Deterioration of natural water bodies due to olive mil wastes is a serious problem as indicated by coloring, appearance of an oily shine, and increased oxygen demand. It affects the soil quality, toxic to plants and soil micro flora when disposed into the soil. Therefore, direct discharge of olive mill wastewater into receiving media is not permissible and certain measures must be taken before disposal of the OMW into the environment (Azbar et al., 2004 and Ergu et al., 2008). Several studies carried out to reduce the phenolic compounds and COD content of this waste by using different treatment methods. Biological treatments by different microorganisms may be fungi such as Aspergillus niger (Hamdi et al., 1991) and Borja et al. (1995); Phanerochaete chrysosporium (Ahmadi et al., 2006), Pleurotus ostreatus (Fountoulakis et al., 2002 and Aggelisa et al., 2003); Lentinula edodes (Annibale et al., 2004); yeasts such as Yarrowia lipolytica and Candida tropicalis (Ettayebi et al., 2003), bacteria such 2 as Azotobacter vinelandii (Piperidou, et al., 2000). Chemical treatments such as photocatal ysis using TiO (Oppenländer, 2003; Konstantinou and Albanis, 2004 and Parsons, 2004); by Fenton system (Benitez et al., 2001; Gernjak et al., 2004 and Dincer et al., 2008). Other treatments were also used such as ultrafiltration (Akdemir and Adem, 2008); electrochemical oxidation (Longhi et al., 2001 and Gotisia et al., 2005).The present study was aimed to reduce the phenolic compounds and COD contents of olive mill wastewater (OMW) by using biological and chemical treatment methods.